Evaluation of the Liver for Metastatic Disease

• ABSTRACT
• BLOOD SUPPLY
• DETECTION BY IMAGING
• ULTRASOUND
• COMPUTED TOMOGRAPHY
• MAGNETIC RESONANCE IMAGING
• IMAGING IN ANTICIPATION OF HEPATIC RESECTION
• IMAGE FINDINGS IN METASTATIC DISEASE
• ULTRASOUND
• COMPUTED TOMOGRAPHY
• MAGNETIC RESONANCE IMAGING
• ABBREVIATIONS
• REFERENCES

ABSTRACT

Metastatic disease of the liver accounts for the vast majority of detected liver masses. In patients with suspected metastatic disease, cross-sectional imaging with ultrasound (US), computed tomography (CT), or magnetic resonance imaging (MRI) is critical. In the group of patients undergoing evaluation for hepatic surgery, it is even more important to optimize techniques to detect and localize metastatic disease. With improvements in technology and contrast agents, there are several approaches to imaging the liver for metastatic disease. The approach will vary by institution. This article will attempt to provide an overview of the general issues relevant to imaging metastatic disease, highlight the advantages and disadvantages of one modality compared to another, and illustrate the appearance of metastases using US, CT, and MRI.

In most institutions metastatic disease accounts for the vast majority of liver masses, far outnumbering primary liver tumors. The true prevalence of hepatic metastatic disease is unknown.[1] Published reports are biased and reflect sampling time relative to the course of the disease. Furthermore, prevalence estimates based on cross-sectional imaging are biased by limitations in detection.[2] However, autopsy series of patients with primary tumors indicate that at the time of death, approximately 50% of patients have metastatic disease of the liver.[3]

The liver is the most common site for metastatic spread of colorectal cancer, which accounts for well over 50,000 deaths per year in the United States alone.[4] The presence of metastatic disease to the liver is a prime determinate of survival. Prognosis is inversely proportional to not only the presence of metastases but also the number and volume of metastases.[5] For example, in patients with metastatic colon cancer, Wagner et al[6] found a 3-year survival rate of 21% in patients with solitary lesions, 6% in those with multiple lesions affecting only one lobe, and 4% in those patients with widespread disease.

Over the last decade, there have been tremendous advances in the treatment of metastatic disease of the liver.[7] Liver resection or liver-directed therapy is justified for select patients when extrahepatic malignancy is not present and the patient can tolerate therapy. With improvements in surgical therapy, most institutions are encountering an increasing number of referrals for liver-directed therapy.

In patients with suspected metastatic disease, cross-sectional imaging is critical. Specific approaches will vary among institutions. This article will provide an overview of cross-sectional imaging of metastatic disease.

BLOOD SUPPLY

The liver is unique because of its dual blood supply from the portal vein and hepatic artery. Approximately 20% of the blood supply is from the hepatic artery and 80% from the portal vein.[8] [9] For most abdominal primary tumors the liver represents the first site to be involved in hematogeneous metastatic spread.[10] [11] It is hypothesized that once tumor cells invade the portal venous system, they seed the hepatic parenchyma, which may represent a favorable environment for tumor growth. The blood supply to tiny or microscopic metastases is primarily from the portal venous system.[1] However, by the time metastases are large enough to be detected by imaging, they receive the majority of their blood from the hepatic artery. It is interesting to note that a significant number of liver metastases up to 1.5 cm in size have a distinct residual portal venous blood supply to the tumor periphery.[12] [13] [14] [15] Such dual vascularity in the smallest of lesions may partly explain some of the difficulty in detecting such lesions with imaging techniques.[1]

Metastases are nearly always multiple. As a general rule, they are more frequently encountered in the right lobe than the left. This is likely due to the large mass of the right lobe and, accordingly, its greater blood flow. Furthermore, laminar flow in the portal vein plays a role because metastases from the gastrointestinal tract spread to the liver via the superior mesenteric vein, which preferentially flows into the right lobe.

DETECTION BY IMAGING

Detection of metastatic disease by imaging is based on lesion size, lesion-to-liver contrast difference, and lesion-to-liver edge definition.[1] [16] To maximize the detection of lesions, it is critical to perform imaging techniques with high spatial resolution. High-spatial resolution imaging can be maximized with thin collimation computed tomography (CT), magnetic resonance imaging (MRI), or ultrasound (US). Thin collimation imaging also results in improved lesion-to-liver edge definition because partial volume artifacts will be reduced.

Because the composition of metastatic deposits differs from the background liver (metastases usually contain more water), they may be detected on CT on MRI studies performed without the administration of contrast material. However, the lesion-to-liver contrast difference will be maximized by selectively enhancing the background liver parenchyma by the administration of contrast material. With CT and MRI, the most common approach to enhance the parenchyma is to inject iodine-containing contrast or gadolinium-containing contrast material, respectively.

There are several methods available to screen the liver for metastatic disease. Choice of modality will be based on clinical scenario and institutional preference. Table [1] lists the sensitivity of a variety of cross-sectional imaging techniques for the detection of individual metastases. Know that lesions less than 1 cm in size are difficult to detect by any modality.[1] Furthermore, be aware that the detection of each and every lesion-critical to the liver surgeon-is far more difficult than detecting patients with metastatic disease, in whom lesion-by-lesion analysis may be less critical.

Hundreds of articles have been written regarding metastatic detection using cross-sectional imaging techniques. Rather than attempt to provide an exhaustive review of the efficacy of each imaging technique, fundamental advantages and disadvantages of each technique will be discussed.

ULTRASOUND

Because of its low capital equipment cost and lack of ionizing radiation, transabdominal US is used frequently to screen the liver for metastatic disease.[1] In most patients, the majority of the liver is well visualized using either the subcostal or intercostal approach. The disadvantages of US are its dependency on operator skill and relative lack of reproducibility from one scan to the next. In many patients the dome of the liver is difficult to evaluate with ultrasound. In obese patients or those with fatty infiltration, it may be difficult or impossible to penetrate the liver with sound. Similarly, overlying ribs or gas-filled loops of bowel limit sound penetration. Despite the potential advantages of ultrasound, many surgeons and oncologists trained in the United States choose to rely on CT or MRI rather than US for screening and/or following patients with metastatic disease.[1] The sensitivity of ultrasound for detecting metastases is similar to that of noncontrast-enhanced CT.

Color Doppler US or power Doppler US has been used to characterize the blood flow within and around hepatic metastases, although the addition of these modalities to conventional gray-scale scanning offers little in terms of detection.[17] [18] [19] [20] [21] [22] [23] Interestingly, recent work suggests that hepatic arterial blood flow is increased in patients with metastatic disease.[24] [25] [26] [27] [28] Leen et al[25] [26] report that the ratio of hepatic artery to portal flow (called the Doppler perfusion index, or DPI) is sensitive for determining the presence of metastatic disease. Even more promising is work that suggests this ratio may be used to identify patients with primary tumors who are at risk for developing metastatic disease on follow-up scans. These promising early results await the result of further scientific inquiry before they can be incorporated into routine clinical practice.

Several injectable US agents have been developed and hold promise for increasing the sensitivity of ultrasound for detecting metastatic disease.[29] [30] [31] [32] [33] [34] [35] [36] [37] [38] The agents either enhance blood flow visualization within or around lesions or enhance the visualization of normal parenchyma. Although US contrast agents show promise in regard to the detection and characterization of metastatic disease, their role in the evaluation of patients with metastases awaits the results of scientific investigation. It is doubtful that contrast-enhanced US will replace well-performed CT and MRI for detecting patients with metastatic disease of the liver.

COMPUTED TOMOGRAPHY

In our practice, contrast-enhanced CT is the mainstay for detecting patients with metastatic disease. Advantages of CT include reasonable capital equipment cost, wide availability, exam-to-exam reproducibility, and extremely short acquisition times.[1] Importantly, CT scans are well accepted by referring surgeons and oncologists. Disadvantages of CT include the use of intravenous contrast material (cost, allergic reactions, nephrotoxicity) and ionizing radiation. With spiral CT scanners, including multidetector scanners, it is now possible to acquire two or even three acquisitions through the liver during a single intravenous (IV) bolus of contrast.[39] [40] This allows imaging to be performed during the so-called hepatic arterial dominant phase of enhancement, which has been shown to be sensitive for detecting hypervascular tumors and allows characterization of both benign and malignant tumors.[41] [42] [43] [44] Although there is a temptation to perform multiple acquisitions during an injection of contrast, each acquisition is associated with increasing radiation and cost. Furthermore, CT is an excellent method to detect extrahepatic disease.

Invasive catheter-assisted CT has been shown to be extremely sensitive for detecting metastatic disease and for many years was routine in patients anticipating liver resection.[45] [46] [47] [48] [49] However, in most institutions invasive catheter-assisted CT (CT angiography or CT arterial portography) has been replaced by well-performed spiral CT using a simple intravenous injection[50] and MRI following IV administration of a liver-specific contrast agent. The main drawback of invasive CT techniques is the requirement for selective placement of a catheter into the hepatic or splenic artery. In addition, the images are often degraded by perfusion defects and areas of hyperenhancement that could easily be mistaken for lesions.[51] [52]

With spiral CT scanners it is now possible to address the imaging issues relevant to liver surgery with a straightforward intravenous injection of contrast that usually obviates the need for catheter-assisted CT. With a single contrast bolus, one may acquire CT images suitable for reconstruction into an excellent-quality CT angiogram, followed by a diagnostic acquisition of the liver to detect and characterize metastatic deposits.[53] [54] [55] [56] [57] The CT angiograms are of sufficient quality to delineate variants of hepatic anatomy, which can aid the liver surgeon in planning resection and placement of hepatic artery pumps for selective perfusion of chemotherapeutic agents (Fig. [1]). The diagnostic scans are sufficiently sensitive for the detection of metastatic disease.[58]

MAGNETIC RESONANCE IMAGING

MRI is well suited for metastatic disease detection because this modality provides high lesion-to-liver contrast and does not use ionizing radiation. Specifically, metastases have long T2 values because they contain abundant water, rendering them particularly bright on T2-weighted sequences. Metastases may also be detected on T1-weighted scans, which may be acquired with or without the injection of intravenous gadolinium contrast agents. When gadolinium contrast agents are injected, the lesion-to-liver conspicuity is increased. Indeed, most studies show that MRI with or without intravenous contrast is slightly more sensitive than CT for the detection of metastatic disease,[46] [47] [48] [49] With current MRI scanners, it is now possible to acquire excellent-quality images of the entire liver within a single breath hold.[59] [60] Such rapid scanning allows dynamic imaging of the liver during a bolus injection of contrast, analogous to dual-phase imaging with CT (Fig. [2]).

In addition to gadolinium, several liver-specific MRI contrast agents have been developed.[60] Supraparamagnetic iron oxide particles (Feridex, Berlex Laboratories, Wayne, NJ) are phagocytized by the reticuloendothelial system of the liver, resulting in decreased signal on T2-weighted images. Because metastases are free of the reticuloendothelial system, they maintain bright signal intensity on T2-weighted scans and become conspicuous compared with the background liver. Another agent is manganese dipyridoxal diphosphate (Mn-DPDP) (Teslascan, Nycomed Laboratories, Princeton, NJ), which is taken up by hepatocytes and excreted in bile.[60] On T1-weighted scans manganese increases signal intensity of the normal liver. Metastases appear relatively dark compared with the enhanced liver. Interestingly this agent allows discrimination of hepatocyte-containing lesions such as hepatic adenomas from metastatic deposits because hepatocyte-containing lesions take up the agent.

Disadvantages of MRI include high capital equipment costs, high maintenance costs, complex imaging protocols, and susceptibility to motion artifacts from cardiac pulsation, respiration, and bowel peristalsis.[1] Exam times are considerably longer with MRI than with CT, which further drives up the cost of MRI. Finally, because of the superiority of MRI in the central nervous system and musculoskeletal system, most clinical MRI centers have a substantial backlog of cases. Despite these disadvantages, MRI has replaced CT for the evaluation of metastatic disease in some centers.

Our approach to most patients with metastatic disease is to perform a precontrast CT of the liver followed by a contrast-enhanced spiral CT scan of the liver and the remainder of the abdomen and pelvis. In patients with suspected hypervascular metastatic disease, a dual-phase acquisition is performed. These CT examinations are reliable, reproducible, and readily available and provide an excellent screen of the liver as well as the extrahepatic tissues. If a patient cannot receive intravenous contrast due to renal insufficiency or history of allergic reaction, we perform MRI instead.

IMAGING IN ANTICIPATION OF HEPATIC RESECTION

In patients undergoing evaluation for hepatic resection, it is important to define not only the number of lesions but also their specific anatomic location.[61] [62] [63] [64] Whether using MRI or CT, prehepatic resection imaging implies maximizing scan quality. Lesions should be measured and counted. Those lesions that are indeterminate should be characterized and described. Not only should lesions be localized to the Couinaud segments, but the relationship of lesions to major anatomic structures (portal and hepatic artery bifurcation, inferior vena cava, and hepatic veins) should be detailed.

Knowledge of the number and specific location of lesions will allow the surgeon to plan an operative approach and to counsel the patient appropriately. Be aware that, with recent advances in hepatic surgery, many patients will not require formal segmental resection. Rather, local therapies including wedge resection, ablative therapy (radio-frequency ablation or cryoablation), or a combination of these techniques with or without segmental resection may be used.[65] Note that with many patients it is difficult to delineate precisely the specific segmental location of a tumor. The more important issue is the relationship of lesions to the major portal, venous, or arterial branches. Knowledge of these relationships allows anticipation of the width of a disease-free surgical margin.[66] Most surgeons will now use open or laparoscopic intraoperative US to detect additional lesions and to localize the disease. Indeed, with the increasing utilization of intraoperative US and the increased number of tools and techniques available to the surgeon, the need to detect all lesions preoperatively is less critical than it was previously.[1] We believe patient care is enhanced by interactively reviewing each case with the surgeon preoperatively.

IMAGE FINDINGS IN METASTATIC DISEASE

The imaging appearance of metastatic disease is nonspecific and varies among primary tumors. Metastases may be solid, cystic, calcified, homogeneous, heterogeneous, hypovascular, hypervascular, diffuse, poorly marginated, and miliary. It is rarely possible to determine the site of a primary tumor based on the appearance of its metastases. Virtually any imaging appearance may appear with any tumor. Biopsy is often required to confirm the suspicion of metastatic disease.

ULTRASOUND

By ultrasound metastases to the liver usually take on one of the following appearances: (1) hypoechoic mass, (2) mixed echogenicity mass, (3) mass with target appearance, (4) uniformly echogenic mass, (5) cystic mass, or (6) heterogeneous or ``coarse'' echo texture without focal mass (Fig. [3]).[1] [67]

Most metastatic deposits are solid and mainly hypoechoic relative to the background liver (Fig. [4]). Many will exhibit a hypoechoic ``halo'' (Fig. [5]). There is some controversy as to whether the halo is composed of compressed normal liver parenchyma, new proliferating tumor, edema, a rim of hypervascularity around a metastasis, or some combination of these etiologies. Suffice it to say, a solid mass in the liver ringed by a halo is most likely a metastatic deposit.

In addition to a halo, metastases may take on a ``target'' or ``bull's-eye'' appearance due to alternating layers of hyper- and hypoechoic tissue. Like a halo, such patterns are also highly suggestive of malignancy.

A uniformly hyperechoic solid mass is usually a benign hemangioma.[67] However, occasionally metastases will be uniformly hyperechoic and may masquerade as hemangiomas. In this scenario, further imaging or biopsy is indicated. Often, hyperechoic metastases correspond to hypervascular lesions, including metastases from renal cell carcinoma, breast carcinoma, and islet cell tumors (Fig. [6]). Hypoechoic masses tend to be hypovascular.

Similarly, simple cysts of the liver usually are not confused with cystic metastases, which nearly always contain septations, debris, mural nodules, or thick walls (Fig. [7]). Metastases that tend to be cystic include those from sarcomas and squamous cell carcinomas, but any primary tumor may present with cystic metastases, particularly following treatment.

A promise of color flow and power Doppler imaging was to differentiate metastases from benign tumors or those of hepatocyte origin. Unfortunately, even with the use of US contrast agents, there is considerable overlap in the appearance of metastases and hepatocellular carcinoma (HCC).[21] On a case-by-case basis, clinical and historical factors influence the determination of tumor type more than the sonographic appearance per se.

Calcifications suggest a mucinous adenocarcinoma, which implies a primary site from the colon, pancreas, or ovary (Fig. [8]). Thyroid carcinoma metastases may also calcify.

One of the strengths of US is to facilitate liver lesion biopsy.[68] With needle tip visualization and the real-time capability afforded by US, the viable nonnecrotic portions of the tumor may be sampled (Fig. [9]). Furthermore, portions of the adjacent normal liver may be avoided, which increases the yield of the specimen. With traditional CT guidance, or even with CT fluoroscopy, such precise needle placement is often not possible.

COMPUTED TOMOGRAPHY

As with ultrasound, the CT manifestations of metastatic disease are varied.[1] On precontrast scans, metastases are nearly always of decreased attenuation compared with the background liver, which is usually of relatively high attenuation due in part to the presence of glycogen within hepatocytes.

Precontrast CT is more sensitive than US for the detection of calcium within a tumor (Fig. [10]). Calcifications may be psammomatous, which creates a stippled appearance or macroscopic dystrophic calcium, which in turn creates chunks of high attenuation. The identification of calcification may aid in the differential diagnosis for the patient who presents with a large heterogeneous hepatic mass. When calcification is present, the most likely diagnosis is a colon cancer metastasis. Treated metastases may also develop calcifications. Occasionally, the use of IV contrast will obscure the presence of calcifications.

After IV contrast has been injected, the appearance of metastases will vary based on vascularity of the lesion and timing of the acquisition (Fig. [11]). Most metastases are relatively hypovascular compared with the background liver and will be of decreased attenuation on pre-contrast, arterial predominant phase, and portal venous predominant phase scans. Metastases that tend to be hypovascular include those from the colon, lung, prostate, and gynecological primaries.

Metastases with abundant arterial blood flow may enhance vividly during the arterial- predominant phase of enhancement (Fig. [12]).[41] [42] [43] [44] These include metastases from neuroendocrine tumors, phenochromocytoma, carcinoid, breast, renal cell carcinoma, and thyroid. In fact, these tumors are often most conspicuous during the hepatic arterial-predominant phase of enhancement, reflecting their increased arterial supply. During the portal venous predominant phase of enhancement, the lesions may be isodense to liver and difficult to detect. Indeed, there is the occasional patient with a hypervascular primary tumor in whom metastases will be entirely missed unless arterial predominant-phase imaging is performed. There is some debate as to which tumors are best imaged with the addition of arterial-phase imaging. Research suggests that metastases from neuroendocrine tumors, including carcinoid and thyroid, are extremely hypervascular and are best seen during the hepatic arterial phase of enhancement.[42] [43] Other so-called hypervascular tumors may be less vascular, including metastases from renal cell carcinoma, breast carcinoma, and melanoma. In these tumors, the added value of the arterial phase is controversial, at least in terms of detection per se.

There is emerging data to indicate that in some metastases, the degree of vascularity may correlate with biological activity. If so, it may be necessary to report not only the size and number of lesions but also the presence of and changes in the degree of enhancement. This speculation awaits the results of scientific inquiry.

As with US, cystic metastases are uncommon by CT. Usually the presence of debris, thick septations, walls, or nodules will allow differentiation from simple benign cysts (Fig. [13]).

A relative pitfall of CT is in the setting of diffuse disease, where CT may underestimate the extent of involvement. Clues to the presence of diffuse replacement of parenchyma by metastatic disease include hepatomegaly, a nodular capsular surface, and indistinct vascular margins.[1] Often, precontrast or arterial-phase imaging demonstrates diffuse disease better than portal venous-phase imaging alone (Fig. [14]). If in doubt, MRI or biopsy will prove helpful.

MAGNETIC RESONANCE IMAGING

By MRI, the appearance of metastases varies based on the imaging sequence performed.[1] [59] [60] Typically, on T1-weighted scans, metastases are of low signal intensity relative to the background liver. On T2-weighted scans, metastases are of high signal intensity relative to the background liver (Fig. [15]). However, the signal intensity of metastases on T2-weighted images is less than that of hemangiomas or cysts, which typically have an intensity similar to fluid in the thecal space or gallbladder. As with CT and US, metastases are usually multiple, round, and heterogeneous. Enhancement characteristics of metastases with gadolinium parallel that of CT. As with US, metastases by MRI may be rimmed by a halo of high signal intensity or appear as a target lesion.

MRI is particularly helpful in the patient with suspected diffuse metastatic disease in whom CT or US might underestimate tumor burden (Fig. [16]).

An additional scenario where MRI is useful is in the patient with fatty infiltration in whom by CT or US it may be difficult to differentiate metastatic deposits from regions of liver that are spared fatty infiltration (Fig. [17]). In this scenario, chemical shift imaging is useful.

On T1-weighted images, some metastases will appear as high signal intensity lesions. This may occur in melanoma deposits due to the paramagnetic effect of melanin, lesions that are hemorrhagic, and necrotic lesions that contain fluid with a high protein concentration.

ABBREVIATIONS

CT computed tomography

DPI Doppler perfusion index

HCC hepatocellar carcinoma

IV intravenous

Mn-DPDP manganese dipyridoxal diphosphate

MRI magnetic resonance imaging

US ultrasound

REFERENCES

• 1 Baker M E, Paulson E K. Hepatic metastatic disease. In: Meyers MA, ed. Neoplasms of the Digestive Tract: Imaging, Staging, and Management Philadelphia: Lippincott-Raven 1998: 361-395
  Search in Google Scholar
• 2 Black W C, Welch H G. Screening for disease.  AJR . 1997;  168 3-11
  PubMedSearch in Google Scholar
• 3 Abrams H L, Spiro R, Goldstein N. Metastases in carcinoma.  Cancer . 1950;  3 74-85
  CrossrefPubMedSearch in Google Scholar
• 4 Parker S L, Tong T, Bolden S. Cancer statistics, 1997.  CA Cancer J Clin . 1997;  47 5-13
  CrossrefPubMedSearch in Google Scholar
• 5 Porte R J, Clavien P-A. Epidemiology and natural history of liver tumors. In: Clavien P-A, ed. Malignant Liver Tumors: Current and Emerging Therapies Malden, MA: Blackwell Science 1999: 27-36
  Search in Google Scholar
• 6 Wagner J S, Atson M A, Van Heerden A J. The natural history of hepatic metastases from colorectal cancer: a comparison with resective treatment.  Ann Surg . 1984;  199 502-508
  CrossrefPubMedSearch in Google Scholar
• 7 Helton W S. The diagnostic and therapeutic approaches to the patient with liver malignancy. In: Clavien P-A, ed. Malignant Liver Tumors: Current and Emerging Therapies Malden, MA: Blackwell Science 1999: 62-85
  Search in Google Scholar
• 8 Fink S, Chaudhuri K. Physiological considerations in imaging liver metastases from colorectal carcinoma.  Am J Physiol Imag . 1991;  6 150-160
  PubMedSearch in Google Scholar
• 9 McCuskey R S. The hepatic microvascular system. In: Arias IM, Boyer JL, Fausto JL, et al, eds. The Liver: Biology and Pathobiology, 4th ed New York: Lippincott-Raven 1994: 1089-1106
  Search in Google Scholar
• 10 Baker M E, Pelley R. Hepatic metastases: basic principles and implication for radiologists.  Radiology . 1995;  197 329-337
  PubMedSearch in Google Scholar
• 11 Morgan-Parkes J H. Metastases: mechanisms, pathways and cascades.  AJR . 1995;  164 1075-1082
  PubMedSearch in Google Scholar
• 12 Lin G, Lunderquist A, Hagerstran I. Postmortem examination of the blood supply and vascular pattern of small liver metastases in man.  Surgery . 1984;  96 517-526
  PubMedSearch in Google Scholar
• 13 Lin G, Hagerstrand I, Lunderquist A. Portal blood supply of liver metastases.  AJR . 1984;  143 53-55
  PubMedSearch in Google Scholar
• 14 Kan Z, Ivancev K, Lunderquist A. In vivo microscopy of hepatic tumors in animal models: a dynamic investigation of blood supply to hepatic metastases.  Radiology . 1993;  187 621-626
  PubMedSearch in Google Scholar
• 15 Haugeberg G, Strohmeyer T, Lierse W. The vascularization of liver metastases.  J Cancer Res Clin Oncol . 1988;  114 415-419
  PubMedSearch in Google Scholar
• 16 Mahfouz A E, Hamm B, Mathieu D. Imaging of metastases to the liver.  Eur Radiol . 1996;  6 607-614
  PubMedSearch in Google Scholar
• 17 Rubin J M, Bude R O, Carson P L. Power Doppler US: a potentially useful alternative to mean frequency-based color Doppler ultrasound.  Radiology . 1994;  190 853-856
  CrossrefPubMedSearch in Google Scholar
• 18 Bude R O, Rubin J M. Power Doppler sonography.  Radiology . 1996;  200 21-23
  PubMedSearch in Google Scholar
• 19 Tanaka S, Kitamura T, Fujita M. Color Doppler imaging of liver tumors.  AJR . 1990;  154 509-514
  PubMedSearch in Google Scholar
• 20 Ralls P W, Johnson M B, Lee K P. Color Doppler sonography in hepatocellular carcinoma.  Am J Physiol Imaging . 1991;  6 57-61
  PubMedSearch in Google Scholar
• 21 Nino-Murcia M, Ralls P W, Jeffrey Jr B R. Color Doppler characterization of focal hepatic lesions.  AJR . 1992;  159 1195-1197
  PubMedSearch in Google Scholar
• 22 Taylor K JW, Ramon I, Morse S S. Focal liver masses: differential diagnosis with pulsed Doppler US.  Radiology . 1987;  164 643-647
  PubMedSearch in Google Scholar
• 23 Ohnishi K, Nomura F. Ultrasonic Doppler studies of hepatocellular carcinoma and comparison with other hepatic focal lesions.  Gastroenterology . 1989;  97 1489-1497
  PubMedSearch in Google Scholar
• 24 Sheafor D H, Killius J S, Paulson E K. Hepatic parenchymal enhancement during triple phase helical CT: can it be used to predict which patients with breast cancer will develop hepatic metastases?.  Radiology . 2000;  214 875-880
  PubMedSearch in Google Scholar
• 25 Leen E, Angerson W J, Wotherspoon H. Detection of colorectal liver metastases: comparison of laparotomy, CT, US, Doppler perfusion index and evaluation of postoperative follow-up results.  Radiology . 1995;  195 113-116
  PubMedSearch in Google Scholar
• 26 Leen E, Goldberg J A, Robertson J. Detection of hepatic metastases using duplex/color Doppler sonography.  Ann Surg . 1991;  214 599-604
  PubMedSearch in Google Scholar
• 27 Platt J F, Francis I R, Ellis J H, Reige K A. Liver metastases: early detection based on abnormal contrast material enhancement at dual-phase helical CT.  Radiology . 1997;  205 49-53
  PubMedSearch in Google Scholar
• 28 Miles K A, Dugdale P E, Leggett D A. CT measurements of hepatic perfusion in colorectal cancer: correlation with outcome at one year.  Radiology (Abstr). 1998;  209 485
  PubMedSearch in Google Scholar
• 29 Remer E M, Gore R M. Liver: normal anatomy in examination techniques. In: Gore RM, Levine MS, ed. Textbook of Gastrointestinal Radiology, 2nd ed Philadelphia: Lippincott-Raven; 2000: 1416-1441
  Search in Google Scholar
• 30 Goldberg B B, Liu J-B, Forsberg F. Ultrasound contrast agents: a review.  Ultrasound Med Biol . 1994;  20 319-333
  CrossrefPubMedSearch in Google Scholar
• 31 Tanaka S, Kitamra T, Yoshioka F. Effectiveness of galactose-based intravenous contrast medium on color Doppler sonography of deeply located hepatocellular carcinoma.  Ultrasound Med Biol . 1993;  21 157-160
  PubMedSearch in Google Scholar
• 32 Tano S, Ueno N, Tomiyama T. Possibility of differentiating small hyperechoic liver tumours using contrast-enhanced color Doppler ultrasonography: a preliminary study.  Clin Radiol . 1997;  52 41-45
  CrossrefPubMedSearch in Google Scholar
• 33 Leen E, McArdle C S. Ultrasound contrast agents in liver imaging.  Clin Radiol . 1996;  51(S1) 35-39
  CrossrefPubMedSearch in Google Scholar
• 34 Forsberg F, Liu J-B, Merton D A. Parenchymal enhancement and tumor visualization using a new sonographic contrast agent.  J Ultrasound Med . 1995;  14 949-957
  PubMedSearch in Google Scholar
• 35 Mattrey R F, Wrigley R, Steinbach G C. Gas emulsions as ultrasound contrast agents: preliminary results in rabbits and dogs.  Inv Radiol . 1994;  29(S2) 139-141
  PubMedSearch in Google Scholar
• 36 Blomley M J, Albrecht T, Cosgrove D O. Improved imaging of liver metastases with stimulated acoustic emission in the late phase of enhancement with US contrast agent SHU508A: early experience.  Radiology . 1999;  210 409-416
  CrossrefPubMedSearch in Google Scholar
• 37 Parker K J, Baggs R B, Lerner R M. Ultrasound contrast for hepatic tumors using IDE particles.  Invest Radiol . 1990;  25 1135-1139
  PubMedSearch in Google Scholar
• 38 Rawool N M, Forsberg F, Liu J. US contrast enhancement in conventional and harmonic imaging modes.  Radiology . 1996;  201(P) 514
  PubMedSearch in Google Scholar
• 39 Heiken J P, Brink J A, Vannier W. Spiral (helical) CT.  Radiology . 1993;  189 647-656
  PubMedSearch in Google Scholar
• 40 Heiken J P, Brink J A, Sagel S S. Helical CT: abdominal applications.  Radiology . 1994;  14 919-924
  PubMedSearch in Google Scholar
• 41 Oliver III H J, Baron R L. Helical biphasic contrast-enhanced CT of the liver: technique, indications, interpretation, and pitfalls.  Radiology . 1996;  201 1-14
  PubMedSearch in Google Scholar
• 42 Hollett M D, Jeffrey Jr B R, Nino-Murcia M. Dual-phase helical CT of the liver: value of arterial phase scans in the detection of small (≤1.5 cm) malignant hepatic neoplasms.  AJR . 1995;  164 879-884
  PubMedSearch in Google Scholar
• 43 Paulson E K, McDermott V G, Keogan M T. Carcinoid metastases to the liver: the role of triple phase helical CT.  Radiology . 1998;  206 143-150
  PubMedSearch in Google Scholar
• 44 Sheafor D H, Frederick M G, Paulson E K. Comparison of unenhanced, hepatic arterial-dominant, and portal venous-dominant phases helical CT for the detection of liver metastases in women with breast carcinoma.  AJR . 1999;  172 961-968
  PubMedSearch in Google Scholar
• 45 Matsui O, Takashima T, Kadoya M. Liver metastases from colorectal cancers: detection with CT during arterial portography.  Radiology . 1987;  165 65-69
  PubMedSearch in Google Scholar
• 46 Nelson R C, Chezmar J L, Sugarbaker P H, Bernardino M E. Hepatic tumors: comparison of CT during arterial portography, delayed CT, and MR imaging for preoperative evaluation.  Radiology . 1989;  172 27-34
  PubMedSearch in Google Scholar
• 47 Heiken J P, Weyman P J, Lee J K. Detection of focal hepatic masses; prospective evaluation with CT, delayed CT, CT during arterial portography, and MR imaging.  Radiology . 1989;  171 47-51
  PubMedSearch in Google Scholar
• 48 Soyer P, Laissy J-P, Sibert A. Focal hepatic masses: comparison of detection during arterial portography with MR imaging and CT.  Radiology . 1994;  190 737-740
  PubMedSearch in Google Scholar
• 49 Paulson E K, Baker M E, Payne S S. Detection of focal hepatic masses: STIR MR versus CT during arterial portography.  JCAT . 1994;  18 581-587
  PubMedSearch in Google Scholar
• 50 Bluemke D A, Paulson E K, Choti M A. Detection of hepatic lesions in candidates for surgery: comparison of ferumoxides enhanced MR imaging and dual phase helical CT.  AJR . 2000;  175 1653-1658
  PubMedSearch in Google Scholar
• 51 Paulson E K, Baker M E, Hilleren D J. CT arterial portography: causes of technical failure and variable liver enhancement.  AJR . 1992;  159 745-749
  PubMedSearch in Google Scholar
• 52 Paulson E K, Baker M E, Spritzer C E. Focal fatty infiltration: a cause of nontumorous defects in the left hepatic lobe during CT arterial portography.  JCAT . 1993;  17 590-595
  PubMedSearch in Google Scholar
• 53 Gao L, Heath D G, Kuszyk B S, Fishman E K. Automatic liver segmentation technique for three-dimensional visualization of CT data.  Radiology . 1996;  201 359-364
  CrossrefPubMedSearch in Google Scholar
• 54 Johnson P T, Heath D G, Kuszyk B S, Fishman E K. CT angiography with volume rendering: advantages and applications in splanchnic vascular imaging.  Radiology . 1996;  200 564-568
  PubMedSearch in Google Scholar
• 55 Rubin G D, Dake M D, Napel S A. Three-dimensional spiral CT angiography of the abdomen: initial clinical experience.  Radiology . 1993;  186 147-152
  PubMedSearch in Google Scholar
• 56 Foley W D, Mallisee T A, Wilson C R. Multiphase hepatic CT with a multislice scanner.  Radiology . 1999;  213(P) 124
  PubMedSearch in Google Scholar
• 57 Wong K, Paulson E K, Nelson R C. Breath-held 3D CT imaging of the liver using multidetector row helical CT.  Radiology . 2001;  219 75-79
  PubMedSearch in Google Scholar
• 58 Valls C, Andia E, Sanchez A. Hepatic metastases from colorectal cancer: preoperative detection and assessment of resectability with helical CT.  Radiology . 2001;  218 55-61
  CrossrefPubMedSearch in Google Scholar
• 59 Semelka R C, Mitchell D G, Reinhold C. The liver and biliary system. In: Higgins CB, Ricak H, Helms CA, eds. Magnetic Resonance Imaging of the Body, 3rd ed. Philadelphia:: Lippincott-Raven 1997: 591-639
  Search in Google Scholar
• 60 Semelka R C, Helmberger T KG. State of the art colon contrast agents for MR imaging of the liver.  Radiology . 2001;  218 27-39
  Search in Google Scholar
• 61 Heiken J P. Liver. In: Lee JKT, Sagel SS, Stanley RJ, Heiken JP, eds. Computed Body Tomography with MRI Correlation Philadelphia: Lippincott-Raven 1998: 701-779
  Search in Google Scholar
• 62 Harned R K, Chezmar J L, Nelson R C. Imaging of patients with potentially resectable hepatic neoplasms.  AJR . 1992;  159 1191-1194
  PubMedSearch in Google Scholar
• 63 Small W C, Mehard W B, Langmo L S. Preoperative determination of the resectability of hepatic tumors: efficacy of CT during arterial portography.  AJR . 1993;  161 319-322
  PubMedSearch in Google Scholar
• 64 Heyneman L E, Nelson R C. Modality for imaging liver tumors. In: Clavien P-A, ed. Malignant Liver Tumors: Current and Emerging Therapies Malden, MA: Blackwell Science 1999: 46-62
  Search in Google Scholar
• 65 Gazelle G S, Goldberg S N, Solbiati L, Livraghi T. State of the art colon tumor ablation with radiofrequency energy.  Radiology . 2000;  217 633-647
  CrossrefPubMedSearch in Google Scholar
• 66 Lee F T. Preoperative imaging of hepatic cancer: what the surgeon needs to know. Presented at the Abdominal Radiology Postgraduate Course; Kaui, Hawaii; March 2000
• 67 Ralls P W, Jeffrey R B. The liver. In: Jeffrey RB, Ralls PW, eds. Sonography of the Abdomen New York: Raven 1995: 71-179
  Search in Google Scholar
• 68 Dodd III D G, Esola C C, Memel D S. Sonography: the undiscovered jewel of interventional radiology.  Radio Graphics . 1996;  16 1271-1288
  PubMedSearch in Google Scholar

REFERENCES

• 1 Baker M E, Paulson E K. Hepatic metastatic disease. In: Meyers MA, ed. Neoplasms of the Digestive Tract: Imaging, Staging, and Management Philadelphia: Lippincott-Raven 1998: 361-395
  Search in Google Scholar
• 2 Black W C, Welch H G. Screening for disease.  AJR . 1997;  168 3-11
  PubMedSearch in Google Scholar
• 3 Abrams H L, Spiro R, Goldstein N. Metastases in carcinoma.  Cancer . 1950;  3 74-85
  CrossrefPubMedSearch in Google Scholar
• 4 Parker S L, Tong T, Bolden S. Cancer statistics, 1997.  CA Cancer J Clin . 1997;  47 5-13
  CrossrefPubMedSearch in Google Scholar
• 5 Porte R J, Clavien P-A. Epidemiology and natural history of liver tumors. In: Clavien P-A, ed. Malignant Liver Tumors: Current and Emerging Therapies Malden, MA: Blackwell Science 1999: 27-36
  Search in Google Scholar
• 6 Wagner J S, Atson M A, Van Heerden A J. The natural history of hepatic metastases from colorectal cancer: a comparison with resective treatment.  Ann Surg . 1984;  199 502-508
  CrossrefPubMedSearch in Google Scholar
• 7 Helton W S. The diagnostic and therapeutic approaches to the patient with liver malignancy. In: Clavien P-A, ed. Malignant Liver Tumors: Current and Emerging Therapies Malden, MA: Blackwell Science 1999: 62-85
  Search in Google Scholar
• 8 Fink S, Chaudhuri K. Physiological considerations in imaging liver metastases from colorectal carcinoma.  Am J Physiol Imag . 1991;  6 150-160
  PubMedSearch in Google Scholar
• 9 McCuskey R S. The hepatic microvascular system. In: Arias IM, Boyer JL, Fausto JL, et al, eds. The Liver: Biology and Pathobiology, 4th ed New York: Lippincott-Raven 1994: 1089-1106
  Search in Google Scholar
• 10 Baker M E, Pelley R. Hepatic metastases: basic principles and implication for radiologists.  Radiology . 1995;  197 329-337
  PubMedSearch in Google Scholar
• 11 Morgan-Parkes J H. Metastases: mechanisms, pathways and cascades.  AJR . 1995;  164 1075-1082
  PubMedSearch in Google Scholar
• 12 Lin G, Lunderquist A, Hagerstran I. Postmortem examination of the blood supply and vascular pattern of small liver metastases in man.  Surgery . 1984;  96 517-526
  PubMedSearch in Google Scholar
• 13 Lin G, Hagerstrand I, Lunderquist A. Portal blood supply of liver metastases.  AJR . 1984;  143 53-55
  PubMedSearch in Google Scholar
• 14 Kan Z, Ivancev K, Lunderquist A. In vivo microscopy of hepatic tumors in animal models: a dynamic investigation of blood supply to hepatic metastases.  Radiology . 1993;  187 621-626
  PubMedSearch in Google Scholar
• 15 Haugeberg G, Strohmeyer T, Lierse W. The vascularization of liver metastases.  J Cancer Res Clin Oncol . 1988;  114 415-419
  PubMedSearch in Google Scholar
• 16 Mahfouz A E, Hamm B, Mathieu D. Imaging of metastases to the liver.  Eur Radiol . 1996;  6 607-614
  PubMedSearch in Google Scholar
• 17 Rubin J M, Bude R O, Carson P L. Power Doppler US: a potentially useful alternative to mean frequency-based color Doppler ultrasound.  Radiology . 1994;  190 853-856
  CrossrefPubMedSearch in Google Scholar
• 18 Bude R O, Rubin J M. Power Doppler sonography.  Radiology . 1996;  200 21-23
  PubMedSearch in Google Scholar
• 19 Tanaka S, Kitamura T, Fujita M. Color Doppler imaging of liver tumors.  AJR . 1990;  154 509-514
  PubMedSearch in Google Scholar
• 20 Ralls P W, Johnson M B, Lee K P. Color Doppler sonography in hepatocellular carcinoma.  Am J Physiol Imaging . 1991;  6 57-61
  PubMedSearch in Google Scholar
• 21 Nino-Murcia M, Ralls P W, Jeffrey Jr B R. Color Doppler characterization of focal hepatic lesions.  AJR . 1992;  159 1195-1197
  PubMedSearch in Google Scholar
• 22 Taylor K JW, Ramon I, Morse S S. Focal liver masses: differential diagnosis with pulsed Doppler US.  Radiology . 1987;  164 643-647
  PubMedSearch in Google Scholar
• 23 Ohnishi K, Nomura F. Ultrasonic Doppler studies of hepatocellular carcinoma and comparison with other hepatic focal lesions.  Gastroenterology . 1989;  97 1489-1497
  PubMedSearch in Google Scholar
• 24 Sheafor D H, Killius J S, Paulson E K. Hepatic parenchymal enhancement during triple phase helical CT: can it be used to predict which patients with breast cancer will develop hepatic metastases?.  Radiology . 2000;  214 875-880
  PubMedSearch in Google Scholar
• 25 Leen E, Angerson W J, Wotherspoon H. Detection of colorectal liver metastases: comparison of laparotomy, CT, US, Doppler perfusion index and evaluation of postoperative follow-up results.  Radiology . 1995;  195 113-116
  PubMedSearch in Google Scholar
• 26 Leen E, Goldberg J A, Robertson J. Detection of hepatic metastases using duplex/color Doppler sonography.  Ann Surg . 1991;  214 599-604
  PubMedSearch in Google Scholar
• 27 Platt J F, Francis I R, Ellis J H, Reige K A. Liver metastases: early detection based on abnormal contrast material enhancement at dual-phase helical CT.  Radiology . 1997;  205 49-53
  PubMedSearch in Google Scholar
• 28 Miles K A, Dugdale P E, Leggett D A. CT measurements of hepatic perfusion in colorectal cancer: correlation with outcome at one year.  Radiology (Abstr). 1998;  209 485
  PubMedSearch in Google Scholar
• 29 Remer E M, Gore R M. Liver: normal anatomy in examination techniques. In: Gore RM, Levine MS, ed. Textbook of Gastrointestinal Radiology, 2nd ed Philadelphia: Lippincott-Raven; 2000: 1416-1441
  Search in Google Scholar
• 30 Goldberg B B, Liu J-B, Forsberg F. Ultrasound contrast agents: a review.  Ultrasound Med Biol . 1994;  20 319-333
  CrossrefPubMedSearch in Google Scholar
• 31 Tanaka S, Kitamra T, Yoshioka F. Effectiveness of galactose-based intravenous contrast medium on color Doppler sonography of deeply located hepatocellular carcinoma.  Ultrasound Med Biol . 1993;  21 157-160
  PubMedSearch in Google Scholar
• 32 Tano S, Ueno N, Tomiyama T. Possibility of differentiating small hyperechoic liver tumours using contrast-enhanced color Doppler ultrasonography: a preliminary study.  Clin Radiol . 1997;  52 41-45
  CrossrefPubMedSearch in Google Scholar
• 33 Leen E, McArdle C S. Ultrasound contrast agents in liver imaging.  Clin Radiol . 1996;  51(S1) 35-39
  CrossrefPubMedSearch in Google Scholar
• 34 Forsberg F, Liu J-B, Merton D A. Parenchymal enhancement and tumor visualization using a new sonographic contrast agent.  J Ultrasound Med . 1995;  14 949-957
  PubMedSearch in Google Scholar
• 35 Mattrey R F, Wrigley R, Steinbach G C. Gas emulsions as ultrasound contrast agents: preliminary results in rabbits and dogs.  Inv Radiol . 1994;  29(S2) 139-141
  PubMedSearch in Google Scholar
• 36 Blomley M J, Albrecht T, Cosgrove D O. Improved imaging of liver metastases with stimulated acoustic emission in the late phase of enhancement with US contrast agent SHU508A: early experience.  Radiology . 1999;  210 409-416
  CrossrefPubMedSearch in Google Scholar
• 37 Parker K J, Baggs R B, Lerner R M. Ultrasound contrast for hepatic tumors using IDE particles.  Invest Radiol . 1990;  25 1135-1139
  PubMedSearch in Google Scholar
• 38 Rawool N M, Forsberg F, Liu J. US contrast enhancement in conventional and harmonic imaging modes.  Radiology . 1996;  201(P) 514
  PubMedSearch in Google Scholar
• 39 Heiken J P, Brink J A, Vannier W. Spiral (helical) CT.  Radiology . 1993;  189 647-656
  PubMedSearch in Google Scholar
• 40 Heiken J P, Brink J A, Sagel S S. Helical CT: abdominal applications.  Radiology . 1994;  14 919-924
  PubMedSearch in Google Scholar
• 41 Oliver III H J, Baron R L. Helical biphasic contrast-enhanced CT of the liver: technique, indications, interpretation, and pitfalls.  Radiology . 1996;  201 1-14
  PubMedSearch in Google Scholar
• 42 Hollett M D, Jeffrey Jr B R, Nino-Murcia M. Dual-phase helical CT of the liver: value of arterial phase scans in the detection of small (≤1.5 cm) malignant hepatic neoplasms.  AJR . 1995;  164 879-884
  PubMedSearch in Google Scholar
• 43 Paulson E K, McDermott V G, Keogan M T. Carcinoid metastases to the liver: the role of triple phase helical CT.  Radiology . 1998;  206 143-150
  PubMedSearch in Google Scholar
• 44 Sheafor D H, Frederick M G, Paulson E K. Comparison of unenhanced, hepatic arterial-dominant, and portal venous-dominant phases helical CT for the detection of liver metastases in women with breast carcinoma.  AJR . 1999;  172 961-968
  PubMedSearch in Google Scholar
• 45 Matsui O, Takashima T, Kadoya M. Liver metastases from colorectal cancers: detection with CT during arterial portography.  Radiology . 1987;  165 65-69
  PubMedSearch in Google Scholar
• 46 Nelson R C, Chezmar J L, Sugarbaker P H, Bernardino M E. Hepatic tumors: comparison of CT during arterial portography, delayed CT, and MR imaging for preoperative evaluation.  Radiology . 1989;  172 27-34
  PubMedSearch in Google Scholar
• 47 Heiken J P, Weyman P J, Lee J K. Detection of focal hepatic masses; prospective evaluation with CT, delayed CT, CT during arterial portography, and MR imaging.  Radiology . 1989;  171 47-51
  PubMedSearch in Google Scholar
• 48 Soyer P, Laissy J-P, Sibert A. Focal hepatic masses: comparison of detection during arterial portography with MR imaging and CT.  Radiology . 1994;  190 737-740
  PubMedSearch in Google Scholar
• 49 Paulson E K, Baker M E, Payne S S. Detection of focal hepatic masses: STIR MR versus CT during arterial portography.  JCAT . 1994;  18 581-587
  PubMedSearch in Google Scholar
• 50 Bluemke D A, Paulson E K, Choti M A. Detection of hepatic lesions in candidates for surgery: comparison of ferumoxides enhanced MR imaging and dual phase helical CT.  AJR . 2000;  175 1653-1658
  PubMedSearch in Google Scholar
• 51 Paulson E K, Baker M E, Hilleren D J. CT arterial portography: causes of technical failure and variable liver enhancement.  AJR . 1992;  159 745-749
  PubMedSearch in Google Scholar
• 52 Paulson E K, Baker M E, Spritzer C E. Focal fatty infiltration: a cause of nontumorous defects in the left hepatic lobe during CT arterial portography.  JCAT . 1993;  17 590-595
  PubMedSearch in Google Scholar
• 53 Gao L, Heath D G, Kuszyk B S, Fishman E K. Automatic liver segmentation technique for three-dimensional visualization of CT data.  Radiology . 1996;  201 359-364
  CrossrefPubMedSearch in Google Scholar
• 54 Johnson P T, Heath D G, Kuszyk B S, Fishman E K. CT angiography with volume rendering: advantages and applications in splanchnic vascular imaging.  Radiology . 1996;  200 564-568
  PubMedSearch in Google Scholar
• 55 Rubin G D, Dake M D, Napel S A. Three-dimensional spiral CT angiography of the abdomen: initial clinical experience.  Radiology . 1993;  186 147-152
  PubMedSearch in Google Scholar
• 56 Foley W D, Mallisee T A, Wilson C R. Multiphase hepatic CT with a multislice scanner.  Radiology . 1999;  213(P) 124
  PubMedSearch in Google Scholar
• 57 Wong K, Paulson E K, Nelson R C. Breath-held 3D CT imaging of the liver using multidetector row helical CT.  Radiology . 2001;  219 75-79
  PubMedSearch in Google Scholar
• 58 Valls C, Andia E, Sanchez A. Hepatic metastases from colorectal cancer: preoperative detection and assessment of resectability with helical CT.  Radiology . 2001;  218 55-61
  CrossrefPubMedSearch in Google Scholar
• 59 Semelka R C, Mitchell D G, Reinhold C. The liver and biliary system. In: Higgins CB, Ricak H, Helms CA, eds. Magnetic Resonance Imaging of the Body, 3rd ed. Philadelphia:: Lippincott-Raven 1997: 591-639
  Search in Google Scholar
• 60 Semelka R C, Helmberger T KG. State of the art colon contrast agents for MR imaging of the liver.  Radiology . 2001;  218 27-39
  Search in Google Scholar
• 61 Heiken J P. Liver. In: Lee JKT, Sagel SS, Stanley RJ, Heiken JP, eds. Computed Body Tomography with MRI Correlation Philadelphia: Lippincott-Raven 1998: 701-779
  Search in Google Scholar
• 62 Harned R K, Chezmar J L, Nelson R C. Imaging of patients with potentially resectable hepatic neoplasms.  AJR . 1992;  159 1191-1194
  PubMedSearch in Google Scholar
• 63 Small W C, Mehard W B, Langmo L S. Preoperative determination of the resectability of hepatic tumors: efficacy of CT during arterial portography.  AJR . 1993;  161 319-322
  PubMedSearch in Google Scholar
• 64 Heyneman L E, Nelson R C. Modality for imaging liver tumors. In: Clavien P-A, ed. Malignant Liver Tumors: Current and Emerging Therapies Malden, MA: Blackwell Science 1999: 46-62
  Search in Google Scholar
• 65 Gazelle G S, Goldberg S N, Solbiati L, Livraghi T. State of the art colon tumor ablation with radiofrequency energy.  Radiology . 2000;  217 633-647
  CrossrefPubMedSearch in Google Scholar
• 66 Lee F T. Preoperative imaging of hepatic cancer: what the surgeon needs to know. Presented at the Abdominal Radiology Postgraduate Course; Kaui, Hawaii; March 2000
• 67 Ralls P W, Jeffrey R B. The liver. In: Jeffrey RB, Ralls PW, eds. Sonography of the Abdomen New York: Raven 1995: 71-179
  Search in Google Scholar
• 68 Dodd III D G, Esola C C, Memel D S. Sonography: the undiscovered jewel of interventional radiology.  Radio Graphics . 1996;  16 1271-1288
  PubMedSearch in Google Scholar