Small nodule detection in cirrhotic livers: evaluation with US, spiral CT, and MRI and correlation with pathologic examination of explanted liver

Ultrasonographic detection of hepatocellular carcinoma: correlation of preoperative ultrasonography and resected liver pathology

AIM

The aim of this study was to determine the sensitivity of ultrasonography for detecting hepatocellular carcinoma in patients who underwent surgical liver resection.

MATERIALS AND METHODS

The preoperative ultrasonography reports of 103 patients who underwent hepatic resection surgery were retrospectively reviewed. The patients had chronic liver disease with good liver function and a relatively normal liver echo-texture. The presence of a mass or masses in the resected part of the liver segments on preoperative ultrasonography was regarded as possible hepatocellular carcinoma, and these results were compared with the surgically resected hepatic lobes or segments. Accuracy for detection was assessed on a lesion-by-lesion basis, on a segment-by-segment basis, and on a patient basis.

RESULTS

One hundred and fifty-seven hepatocellular carcinomas were found in 244 hepatic segments of 103 patients. One hundred and one of 157 hepatocellular carcinomas were detected using ultrasonography in 97 patients resulting in a sensitivity of 64%. In six patients, a solitary hepatocellular carcinoma was missed in each patient, a patient sensitivity being 94%. Using ultrasonography, 87 of 100 (87%) hepatocellular carcinomas larger than 2 cm in diameter, and 14 of 57 (25%) hepatocellular carcinomas 2 cm or smaller in diameter were revealed. On the basis of segment-by-segment analysis, the sensitivity was 78% (99 of 127 segments), specificity was 97% (114 of 117 segments), accuracy was 87% (213 of 244 segments), positive predictive value was 97% (99 of 102 segments), and negative predictive value was 80% (114 of 142 segments).

CONCLUSION

In patients with chronic liver disease and good hepatic function, ultrasonography has a sensitivity of 94% in the identification of affected patients, but for individual lesions, the sensitivity is only 64%.

The diagnosis and management of benign hepatic tumors

Benign hepatic tumors include a broad spectrum of regenerative and true neoplastic processes. Because of advances in imaging studies such as computed tomography (CT) and magnetic resonance imaging (MRI) as well as progress in immunohistochemistry, accurate diagnosis can now be made in a large percentage of patients without surgical laparotomy or resection. This article will focus on the pathogenesis, diagnosis, and management of focal benign lesions of the liver. Many of these tumors present with typical features in various imaging studies. On occasions, biopsies are required and/or surgical removal is needed. The most common benign hepatic tumors include cavernous hemangioma, focal nodular hyperplasia, hepatic adenoma, and nodular regenerative hyperplasia. In the majority of cases of benign hepatic tumors, patients are asymptomatic, and no treatment is indicated. The main indication for treatment is the presence of significant clinical symptoms or suspicion of malignancy or fear of malignant transformation.

MRI in detection of hepatocellular carcinoma (HCC)

Hepatocellular carcinoma (HCC) is the commonest malignancy of the liver and is usually due to cirrhosis. Early detection of HCC and the premalignant dysplastic nodules has implications on the management options of tumor ablation, liver resection and transplantation. Magnetic resonance imaging is useful for the detection and characterization of lesions, in the identification of dysplastic nodules and their malignant transformation into HCC.

Perfusion imaging of the liver: current challenges and future goals

Improved therapeutic options for hepatocellular carcinoma and metastatic disease place greater demands on diagnostic and surveillance tests for liver disease. Existing diagnostic imaging techniques provide limited evaluation of tissue characteristics beyond morphology; perfusion imaging of the liver has potential to improve this shortcoming. The ability to resolve hepatic arterial and portal venous components of blood flow on a global and regional basis constitutes the primary goal of liver perfusion imaging. Earlier detection of primary and metastatic hepatic malignancies and cirrhosis may be possible on the basis of relative increases in hepatic arterial blood flow associated with these diseases. To date, liver flow scintigraphy and flow quantification at Doppler ultrasonography have focused on characterization of global abnormalities. Computed tomography (CT) and magnetic resonance (MR) imaging can provide regional and global parameters, a critical goal for tumor surveillance. Several challenges remain: reduced radiation doses associated with CT perfusion imaging, improved spatial and temporal resolution at MR imaging, accurate quantification of tissue contrast material at MR imaging, and validation of parameters obtained from fitting enhancement curves to biokinetic models, applicable to all perfusion methods. Continued progress in this new field of liver imaging may have profound implications for large patient groups at risk for liver disease.

Detection of hepatocellular carcinoma: comparison of Gd-DTPA- and ferumoxides-enhanced MR imaging

The aim was to compare the diagnostic performance of dynamic Gd-DTPA- and ferumoxides-enhanced MRI for hepatocellular carcinoma (HCC). Twenty-five patients with chronic hepatitis or liver cirrhosis underwent both dynamic gadopentetate- and ferumoxides-enhanced MRI studies of the liver for HCC detection on the same day. MR data of both studies were retrospectively and independently analyzed. Two observers determined in consensus the grade of diffuse fibrotic liver changes (mild, moderate or severe) and the number of focal lesions. HCCs were confirmed by histology (n=22) and/or follow-up studies for at least six months (n=64). Differences in results obtained from both MR data sets were tested for significance with the McNemar's test (p<0.05). Ferumoxides-enhanced MR images detected 84 of 99 hepatic lesions, including 82 of 86 HCCs and 2 false positive, nonmalignant lesions, while Gd-DTPA-enhanced MR images detected 92 of 99 hepatic lesions, including 81 of 86 HCCs and 11 false positive, nonmalignant lesions. Sensitivity of MRI for detection of HCCs was not significantly different between ferumoxides-enhanced (95.3%; p>0.05) and Gd-DTPA-enhanced scans (94.2%). Gd-DTPA- and ferumoxides-enhanced MRI perform equally well for HCC detection. The majority of small hypervascular hepatic lesions, detected on dynamic Gd-DTPA-enhanced MRI but not on ferumoxides-enhanced MRI, represent no HCCs.

Liver transplantation for hepatocellular carcinoma in cirrhosis: is clinical tumor classification before transplantation realistic?

BACKGROUND

The decision of whether to proceed with transplantation in patients with hepatocellular carcinoma (HCC) in cirrhosis is based on clinical and imaging findings. The purpose of our study was to evaluate the accuracy of the current system.

MATERIALS AND METHODS

We evaluated data of 70 patients with HCC who underwent liver transplantation (LTx) at our center. We specifically analyzed the correlation between preoperative imaging studies and postoperative anatomopathologic findings. Tumor-node-metastasis, Milan, and University of California San Francisco (UCSF) classifications were used. Patients were divided in 2 groups: (1) Patients undergoing live-donor LTx (LDLTx, n=35) and (2) patients undergoing cadaveric LTx (CLTx, n=35).

RESULTS

Only 10 (14.3%) of the 70 patients considered had tumor diameter that was correctly identified by pretransplant radiologic examinations. Twenty-four (34.2%) patients had correct identification of the number of tumors present. Fifty (71.4%) patients had incorrect measurements of tumor diameter of more than 1 cm. Sensitivity of radiologic imaging was especially poor for tumors between 1 and 2 cm and less than 1 cm (21% and 0%, respectively). Best accuracy of 60% was found for both the Milan and UCSF criteria. No significant difference was found between the two patient groups concerning the accuracy of the various systems/criteria of classification.

CONCLUSIONS

Current imaging techniques have a high incidence of false-negative and false-positive results when evaluating HCC in cirrhosis. A critical appraisal of patient characteristics together with great caution when interpreting imaging studies is recommended to determine candidacy for transplantation.

Characterization of Hepatocellular Tumors

PURPOSE

To assess the value of mangafodipir trisodium-enhanced MR imaging for characterization of hepatocellular lesions.

MATERIALS AND METHODS

Magnetic resonance images of 41 patients with 48 histopathologically proven hepatocellular lesions (20 cases of focal nodular hyperplasia [FNH], 4 adenomas, 15 hepatocellular carcinomas [HCCs], 7 regenerative nodules, and 2 others) were retrospectively studied. Magnetic resonance imaging was performed on a 1.5-T unit (Vision, Siemens, Erlangen, Germany; ACS-NT, Philips, Best, The Netherlands) using T2-weighted, fat-saturation, turbo spin echo imaging and T1-weighted gradient echo imaging before and 20 minutes after infusion of 5 micromol/kg mangafodipir (Amersham Health, Oslo, Norway). Qualitative analysis by 4 blinded independent readers included assessment of unenhanced images and, in a second step, assessment of unenhanced and contrast-enhanced images together. Lesions were classified as benign or malignant using a 5-point scale, and readers made a specific diagnosis.

RESULTS

For characterization of hepatocellular lesions, mangafodipir-enhanced imaging was significantly superior to unenhanced imaging (P < 0.05). On receiver operating characteristic analysis, the area under the curve was 0.768 (95% confidence interval: 0.633-0.903) for unenhanced images and 0.866 (95% confidence interval: 0.767-0.966) for evaluation of unenhanced and contrast-enhanced images together (P < 0.05). Analysis of enhancement patterns aided in characterization and classification of tumors.

CONCLUSION

Administration of mangafodipir improves the differentiation between adenoma or HCC and "nonsurgical" lesions (FNH or regenerative nodules). The accuracy for arriving at a specific diagnosis is higher when unenhanced and mangafodipir-enhanced images are considered together than for unenhanced MR images alone.

Risk of hepatocellular carcinoma in liver mitochondrial respiratory chain disorders

Mitochondrial respiratory chain disorders (MRCD) are a large group of disorders that can affect any organ besides muscles or the central nervous system. We report two children who presented with neonatal cholestasis and progressive cirrhosis, who subsequently developed hepatocellular carcinoma (HCC). This suggests a particular risk of degeneration in these patients and the importance of a regular screening for secondary liver cancer. Suggestion of HCC should lead to early liver transplantation, which was successful without tumor recurrence in the two patients.

Improving the prediction of hepatocellular carcinoma in cirrhotic patients with an arterially-enhancing liver mass

In the United States, cirrhotic patients with known or suspected hepatocellular carcinoma (HCC) are prioritized for liver transplantation. Noninvasive criteria for the diagnosis of HCC rely on arterial enhancement of a mass. The aim of this study was to determine whether clinical, laboratory, and / or radiologic data can improve the prediction of HCC in cirrhotic patients with an arterially-enhancing mass. Between May 2002 and June 2003, dynamic gadolinium-enhanced magnetic resonance imaging (MRI) of consecutive patients with liver cirrhosis and a solid mass were reviewed by 2 radiologists blinded to the clinical diagnosis. Clinical, laboratory, and radiologic data were recorded for all patients. A total of 94 patients with cirrhosis and an arterially-enhancing liver mass were studied, 66 (70%) of whom had HCC. Alpha-fetoprotein (AFP) >20 ng/mL (P = .029), tumor size >2 cm (P = .0018), and delayed hypointensity (P = .0001) were independent predictors of HCC. Delayed hypointensity of an arterially-enhancing mass had a sensitivity of 89% and a specificity of 96% for HCC. The presence of delayed hypointensity was the only independent predictor of HCC among patients with arterially-enhancing lesions <2 cm (odds ratio, 6.3; 95% confidence interval [CI], 1.8-13), with a sensitivity of 80% and a specificity of 95%. In conclusion, delayed hypointensity of an arterially-enhancing mass was the strongest independent predictor of HCC, regardless of the size of the lesion. If additional studies confirm our results, the noninvasive criteria utilized to make a diagnosis of HCC should be revised.

Triple Arterial Phase Dynamic MRI with Sensitivity Encoding for Hypervascular Hepatocellular Carcinoma: Comparison of the Diagnostic Accuracy Among the Early, Middle, Late, and Whole Triple Arterial Phase Imaging

OBJECTIVE

We assessed and compared the diagnostic accuracy of the early, middle, late, and whole triple arterial phase MRI with sensitivity encoding (SENSE) for the detection of hypervascular hepatocellular carcinoma (HCC).

MATERIALS AND METHODS

Thirty-one patients with 102 HCCs underwent dynamic MRI with SENSE. The findings of CT examinations, combined with those of visceral angiography or histopathologic examination, were used as the gold standard. After acquisition of T1- and T2-weighted images, gadolinium-enhanced triple arterial, portal, and delayed phase images were obtained. Acquisition of the triple arterial phase imaging was started at the timing of peak aortic enhancement and completed within a single breath-hold. Acquisition time for each phase was 8.4 sec. Four image sets including the early, middle, late, and whole triple arterial phase imaging were interpreted separately by four observers. The mean values of area under alternative-free-response receiver operating characteristic (AFROC) curve and of sensitivity were compared among the four image sets.

RESULTS

The mean values of area under AFROC curve were 0.52, 0.66, 0.53, and 0.68 and of sensitivity were 45%, 64%, 48%, and 65% for the image sets with the early, middle, late, and whole triple arterial phase imaging, respectively. Both mean values were significantly higher for the image sets with the middle and whole triple arterial phase imaging than for those with the early and late arterial phase imaging.

CONCLUSION

The middle arterial phase imaging with k-space centered at 12.6 sec after the peak aortic enhancement was optimal for detecting HCC and showed diagnostic accuracy equivalent to that of the whole triple arterial phase imaging.

Contrast-enhanced sonographic appearance of hepatocellular carcinoma in patients with cirrhosis: comparison with contrast-enhanced helical CT appearance

OBJECTIVE

We sought to investigate the efficacy of contrast-enhanced sonography using a second-generation contrast agent for the evaluation of hepatocellular carcinoma in patients with cirrhosis by comparing the results to those obtained with contrast-enhanced helical CT.

SUBJECTS AND METHODS

Between October 2002 and March 2003, 74 patients with cirrhosis (60 men and 14 women; age range, 47-80 years; mean age, 67 years) who had a single nodule of hepatocellular carcinoma were selected to be studied from a cohort of 437 patients with cirrhosis. The size range of the 74 nodules was 9-65 mm (mean, 28.2 mm). Twenty-eight (38%) were 20 mm smaller (range, 9-20 mm; mean, 16.6 mm), and 46 (62%) were larger than 20 mm (range, 21-65 mm; mean, 35.2 mm). Contrast-enhanced sonography was performed at a low mechanical index after IV administration of the contrast agent SonoVue. CT scans were obtained in all patients. The enhancement pattern related to tumor hypervascularity was analyzed. The chi-square test was used for statistical analysis.

RESULTS

For the 28 hepatocellular carcinomas 20 mm or smaller, contrast-enhanced sonography showed 15 (53.6%) as hypervascular and 10 (35.7%) as avascular; three (10.7%) carcinomas were missed. On CT, 12 (42.9%) of the 28 hepatocellular carcinomas appeared hypervascular, 13 (46.4%) appeared hypovascular, and three (10.7%) were missed. For the 46 hepatocellular carcinomas larger than 20 mm, contrast-enhanced sonography showed 42 (91.3%) as hypervascular and four (8.7%) as avascular. On CT, 35 (76.1%) hepatocellular carcinomas appeared hypervascular, eight (17.4%) appeared hypovascular, and three (6.5%) were missed. Differences between CT appearance of hepatocellular carcinomas and contrast-enhanced sonographic appearance of the carcinomas were not statistically significant. Concordance between contrast-enhanced sonographic and CT appearances was observed in 61 (82.4%) of 74 cases.

CONCLUSION

Contrast-enhanced sonography is similar to CT for detecting hepatocellular carcinoma hypervascularity. It could be complementary to conventional unenhanced sonography for evaluation of liver nodules.

Magnetic resonance imaging of hepatocellular carcinoma

Hepatocellular carcinoma (HCC), the most common primary hepatic malignancy, usually develops in patients with cirrhosis, growing sequentially from low-grade dysplastic nodules to frank malignant HCC. Its recognition is critical because curative treatment and prognosis require early diagnosis. Survival in patients with HCC relates directly to the number, size, and extent of lesions at diagnosis. Imaging of HCC is complicated because the tumor has a varied imaging appearance and frequently coexists with other cirrhotic nodules. Magnetic resonance imaging (MRI), the best available diagnostic technique, offers good contrast resolution and diagnostic sensitivity ranging from 33% to 77%. The main difficulty is not in diagnosing large tumors, but rather small tumors (<2 cm), because of considerable overlap on imaging between benign (regenerative), borderline (dysplastic), and malignant nodules. Increasing degrees of histological malignancy are associated with increasing arterialization and loss of portal blood supply; therefore, recognition of HCC requires dynamic imaging with gadolinium-enhanced T1-weighted sequence. Typically, HCC is a focal lesion with high signal intensity on T2-weighted images, variable signal intensity on T1-weighted images, intense arterial phase enhancement after gadolinium injection, and isointensity or hypointensity at the portal venous phase. The sensitivity of MRI for detecting small lesions is low, and improvement is still needed. Newer contrast agents, higher field strength (3 Tesla) imaging, and perfusion and diffusion MRI techniques possibly will provide greater sensitivity and specificity for detecting small HCCs in the future.

Hepatocellular carcinoma - issues in imaging

The imaging diagnosis of hepatocellular carcinoma is challenging as benign hypervascular lesions and arterioportal shunts (pseudolesions) often mimic it. There is also overlap in the imaging appearance from dysplastic and regenerating nodules. This article addresses the above imaging problems, examines proposed non-invasive imaging criteria for the diagnosis of hepatoma and discusses the optimal imaging modality.

Treatment of hepatocellular carcinoma with percutaneous radiofrequency ablation: usefulness of contrast harmonic sonography for lesions poorly defined with B-mode sonography

OBJECTIVE

The purpose of this study was to assess the usefulness of contrast harmonic sonography guidance in percutaneous radiofrequency ablation of hepatocellular carcinomas that could not be adequately depicted by B-mode sonography. SUBJECTS AND METHODS. Twenty-one patients with 21 hepatocellular carcinomas prospectively underwent radiofrequency ablation treatment with contrast harmonic sonography as guidance. Twenty-five patients with 25 hepatocellular carcinomas were retrospectively selected as the historical control group under the same conditions as the study group; the control group patients were treated under B-mode sonography guidance.

RESULTS

Twenty (95.2%) of the 21 patients were successfully treated during a single treatment session, and the remaining patient (4.8%) required two treatment sessions with contrast harmonic guidance. On the other hand, only eight (32%) of the 25 control subjects were successfully treated during a single treatment session using B-mode sonographic guidance without contrast imaging. The difference between these two groups was statistically significant (p = 0.002).

CONCLUSION

Contrast harmonic sonography helps in the placement of radiofrequency ablation electrodes in hypervascular hepatocellular carcinomas that cannot be adequately depicted by B-mode sonography.

Systematic review of radiological imaging for hepatocellular carcinoma in cirrhotic patients

We systematically reviewed the evidence for determining the best radiological imaging for characterizing hepatocellular carcinoma (HCC) in cirrhotic patients in 997 articles between 1995 and 2001. We selected only prospective and retrospective cohorts of patients, excluding both case reports and studies without separate data on HCC. Only 29 studies, comprising 918 patients, fulfilled the inclusion criteria: 10 used the explanted liver as the reference standard of diagnosis. All except one, either found no statistically significant difference between imaging modalities or had no direct comparison of sensitivity between different modalities of imaging; 16 studies evaluated HCC among cirrhotic patients and had biopsy or imaging as the reference standard for diagnosis. However, no one imaging technique was shown to be superior. In two studies, data of a HCC subgroup was derived from the studies evaluating different kinds of focal hepatic lesions. No conclusion could be drawn because of the small sample size. One study addressed the issue of therapeutic impact. The evidence for choosing the best modality of imaging for characterizing HCC in cirrhotic patients is inadequate. Large multicentre studies with defined reference standards for diagnosis, and studies evaluating therapeutic impact are needed.

Imaging of Dysplastic Nodules and Small Hepatocellular Carcinomas: Experience with Explanted Livers

Differentiation of benign from malignant nodules in the end-stage cirrhotic liver can be challenging, due to the presence of fibrosis, necrosis and altered blood supply. Whole liver explant pathologic correlation provides a unique opportunity to evaluate the sensitivity and specificity of current imaging modalities for the diagnosis of HCC and dysplastic nodules in the cirrhotic liver. This chapter will explore and critique the imaging literature with an emphasis on studies performed with timely explanted liver correlation.

Liver transplantation for hepatocellular carcinoma validation of present selection criteria in predicting outcome

Appropriate patient selection is crucial in ensuring acceptable outcomes from orthotopic liver transplantation (OLT) for hepatocellular carcinoma (HCC). The United Network for Organ Sharing (UNOS) has elected to prioritize HCC patients for OLT based on criteria of tumor burden. However, it is unclear whether these criteria correlate with outcome, or with the pathobiological features associated with tumor recurrence. Therefore, we analyzed 109 consecutive patients undergoing OLT for HCC at our center, to determine the utility of present selection criteria in predicting outcome. Pathologic tumor staging of the explanted liver was based on the American Tumor Study Group modified tumor node metastases (pTNM) classification system. Multifocality was defined as >4 tumor nodules on explant. Survival analysis was performed using Kaplan-Meier and Cox proportional hazards regression methods. At a median follow-up of 18.9 months, the overall mortality was 19% with 15 patients (14%) dying of recurrent HCC. Kaplan-Meier 1, 3 and 5-year survival rates were 89.5%, 68%, and 65%, respectively. Recurrence-free rates of 1, 3, and 5 years were 89%, 75%, and 65%, respectively. On univariate analysis, the factors found to be significantly associated with recurrence of HCC were explant features of macrovascular invasion, tumor size (per centimeter increase), pTNM stage (per 1-stage increase), and pre-transplant serum alphafetoprotein (AFP) >300 ng/mL. In defining a threshold level, we found that explant tumor diameter > or =3 cm, and those tumors classified as at least pT3 on pathological examination, were significantly associated with recurrence (P =.01 and.03, respectively). Tumor size on explant was found to be strongly correlated with multifocality (P =.017) and vascular invasion (P =.02). Patients exceeding pathological UNOS criteria were 3.1 times more likely to have recurrence of HCC (P =.03). In conclusion, we found that tumor size appears to be a surrogate marker for negative pathobiological predictors of outcome, i.e., vascular invasion and multifocality. Present UNOS selection criteria for HCC based on tumor burden appear to provide adequate discriminatory power in predicting outcome of OLT.

Modern hepatic imaging

This article provides a brief overview of the current status of commonly employed diagnostic techniques--US, CT, MR, and PET--for the evaluation of liver metastases and HCC as well as a description of imaging in RF ablation and liver transplantation. The various advantages and limitations of the techniques have been outlined. At the present time, at our center, MRI is used most often to evaluate these liver pathologies, due to its high accuracy for lesion detection and characterization.

[Ultrasound imaging of focal liver lesions with contrast agents: which clinical applications?]

The contrast-enhanced ultrasonography is a promising technique for the diagnosis of focal liver lesion with an increased sensitivity for the tumour detection and a direct visualization of the tumour vascularity. The future applications of this technique will probably depend on the clinical context: in case of suspicion of benign tumour, contrast injection should be able to facilitate the characterization of hemangiomas and focal nodular hyperplasia, when hepatic metastases are researched, it may improve the detection of small lesions in cirrhotic patients, it may facilitate the detection of small hepatocellular carcinomas and find a place in the systematic screening for these tumours. The recently published data are encouraging, but a confirmation of the clinical interest of this technique, and its place within the imaging diagnostic strategies still have to be performed.

MRI features of regenerative and dysplastic nodules in cirrhotic liver

AIM: To study MR features of the regenerative nodule (RN) and dysplastic nodule (DN) in the cirrhotic liver.

METHODS: MRI was performed in 26 cases of suspected cirrhotic liver with RN and DN. Additional enhanced MRI with administration of Gd-DTPA on T1WI was performed in 18 of 26 cases. Meanwhile in 10 of 18 both Gd-DTPA and SPIO (Feridex) enhancement were underwent one day apart. All patients were confirmed by aspiration biopsy or histopathology. MRI was compared to the pathological findings.

RESULTS: In 26 cases, there were 12 cases of regenerative nodules measuring 0.3-1cm in size, and 14 dysplastic nodules including 8 nodules measuring ≥1 cm and <3 cm in size, and 6 nodules measuring ≥3 cm. Their MR appearances were as followings: nodules with <1 cm in size showed isointensity on T₁WI and hypointensity on T₂WI, of which the intensity was as isointense as the surrounding hepatic parenchyma on enhanced MRI with administration of Gd-DTPA or SPIO. In 8 cases with nodules measuring 1-3 cm in size, 5 cases appeared hyperintense on T1WI and hypointense on T₂WI as well as the enhancement as that of nodules with <1 cm in size; the other 3 cases appeared hypointense on T₁WI and hyperintense on T₂WI, and were enhanced after administration of Gd-DTPA but hyperintense on SPIO enhancing MRI, which indicated malignant transformation of dysplastic nodule into hepatocellular carcinoma (HCC) arising from hepatic nodule on histopathology. In 6 cases of nodules measuring >3 cm in size, 2 cases appeared hyperintense compared to the surrounding hepatic parenchyma on T₁, T₂WI and enhanced MRI, one of which was documented "nodule within a nodule" on T₂WI. The 2 cases were demonstrated well-differentiated HCC. The other 4 cases showed hyperintense on T1WI, and hypointense on T₂WI and enhanced MRI. Sometimes, normal vessels were seen to pass through the surface of macroregenerative nodule. Additionally, RN and DN had the same pattern of the time-signal intensity course as the normal surrounding hepatic parenchyma, but malignant transformation of DN appeared fast wash-in and wash-out.

CONCLUSION: RN of cirrhosis has features on MRI that usually allow distinction from HCC but not always from DN. A helpful distinction between HCC and DN is that the latter is almost never hyperintense on T₂WI. Additionally, the followings indicate malignant transformation of DN when DN appears a ring like enhancement after injection of Gd-DTPA, and fast wash-in and wash-out as well as hyperintensity on SPIO enhanced MRI.

Hepatocellular nodules in cirrhosis: focus on diagnostic criteria on liver biopsy. A Western experience

The spectrum of so-called space-occupying small (0.5-2.5 cm) sizable nodules arising in the cirrhotic liver includes a series of hyperplastic (large regenerative), dysplastic (low- and high-grade dysplastic), and malignant hepatocellular (well-differentiated hepatocellular carcinoma, HCC) nodules. Major progress in their classification and understanding was achieved through image analysis techniques and careful histological dissection of explanted native livers. Needless to say, the actual understanding of their natural history is crucial to a proper histological classification. The differential diagnosis of these hepatocellular nodules is difficult, particularly on biopsy specimens of focal liver lesions revealed by ultrasound (US), taken during the follow-up of cirrhotic patients. In this study we attempted to summarize, on the basis of our experience, essential clinicopathological features useful to distinguish the different nodules on needle biopsy. Synoptic tables of differential diagnosis and figures of elementar lesions, which have to be looked for, are provided. Only the continuous integration of clinical features, image analysis information of pathological findings, and follow-up data allows establishing the autonomy of these polymorphic and controversial entities and the boundaries between them.

Fine needle biopsy of focal liver lesions: the hepatologist's point of view

Guided biopsy of hepatocellular carcinoma has been recently discussed again due to the progress of imaging techniques and the risk of malignant seeding after the procedure. Ultrasound is probably still the most accurate imaging modality for early detection of nodules arising on cirrhosis, even when compared with more advanced imaging techniques. It can be easily employed in the surveillance of high-risk cirrhotic patients. Ultrasound-guided biopsy has very high sensitivity and almost absolute specificity, which allows the appropriate treatment to start after a positive diagnosis. It also allows correct diagnosis of lymphomatous nodules, the incidence of which is increased in hepatitis C virus-related cirrhosis. The risk of seeding appears limited according to the currently available epidemiological data; this should be considered against the risk of false-positive diagnosis of malignancy based on imaging studies alone. Ultrasound-guided biopsy is a valuable tool also for the diagnosis of small nodules (less than 10 mm in diameter). The best accuracy in the sampling of hepatocellular carcinoma nodules is obtained by combining smear cytology and microhistology. This can be achieved by a single biopsy with a fine cutting needle that furnishes pathologic material suitable for both examinations, reducing risks and costs.

Pseudohypocalcemia after magnetic resonance imaging with gadolinium in patients with cirrhosis

Hypocalcemia in patients with cirrhosis may be due to a number of causes. We noted a relationship between injection with gadodiamide, a particular gadolinium chelate, during magnetic resonance imaging of the liver and the development of a falsely low serum total calcium level in a patient with cirrhosis. A cross-reference and retrospective chart review identified 10 additional patients in whom this phenomenon was noted. We describe the temporal relationship and clinical characteristics of these patients. Pseudohypocalcemia following magnetic resonance imaging with gadodiamide contrast should be considered in the differential diagnosis of hypocalcemia in patients with cirrhosis.

MRI angiography is superior to helical CT for detection of HCC prior to liver transplantation: an explant correlation

Helical computerized tomography (CT) and magnetic resonance imaging (MRI) are used for staging of hepatocellular carcinoma (HCC) prior to curative treatments but underestimate tumor extension in 30% to 50% of cases when compared with pathologic explants. This study compares a new technology, MRI angiography (MRA), with triphasic helical CT in detection of HCC. Fifty cirrhotic patients, 29 with HCC, undergoing liver transplantation were analyzed. MRA was performed with a 3-D breath-hold fast spoiled gradient-echo sequence by using an effective section thickness of 2 to 2.5 mm. The gold standard was the pathologic examination (liver cut into 5-mm slices). One hundred twenty-seven lesions were identified at the explant: 76 HCC, 13 high-grade dysplastic nodules, 31 macroregenerative nodules, 7 hemangiomas. Diameter of the main HCC nodules was 29 +/- 14 mm and 11 +/- 7 mm for the 47 additional nodules. On a per nodule basis, sensitivity of MRA was superior to CT (58/76 [76%] vs. 43/70 [61%], respectively, P =.001). Sensitivity of MRA for detection of additional nodules decreased with size (>20 mm: 6/6 [100%]; 10-20 mm: 16/19 [84%]; <10 mm: 7/22 [32%]) and was superior to CT for nodules 10 to 20 mm (84% vs. 47%, P =.016). Nonspecific hypervascular nodules >5 mm at MRA were HCC in two thirds of the cases. In conclusion, MRA has a high diagnostic accuracy for HCC > or =10 mm and is more sensitive than triphasic helical CT in nodules sized 10 to 20 mm. MRA is the optimal technique for HCC staging prior to curative therapies.

Small hepatocellular carcinomas in patients with liver cirrhosis: potentials and limitations of contrast-enhanced power Doppler sonography

Detection and characterization of focal liver lesions are critical for patients with liver cirrhosis. The potential of contrast-enhanced sonography in the characterization of focal liver lesions is well established in the literature. However, prospective studies in the assessment of patients with suspected hepatocellular carcinoma (HCC) in liver cirrhosis are rare. B-mode imaging often cannot differentiate small focal lesions in cirrhotic livers. Also, power Doppler is not capable of characterizing small focal lesions in cirrhosis. Contrast-enhanced sonography with a first-generation enhancer seems to improve the accuracy of diagnosis of small HCC. The differentiation of HCC and dysplastic nodules is notoriously difficult. In addition, other arterial hypervascularized liver lesions should be considered, depending on the clinical background. The limitations and drawbacks of contrast-enhanced sonography should be considered. All imaging methods are of limited value in the detection of solid liver lesions smaller than 1 cm.

Individualizing therapy in gastric cancer

Although its incidence in developed countries has declined, gastric cancer remains one of the most common human malignancies. In western countries a shift from distal to proximal tumors has been noted during the past 15 years. Today, surgery is no longer the only treatment modality of gastric cancer, with the help of modern and sophisticated staging procedures it becomes increasingly possible to individually tailor therapy. Operative morbidity and mortality has markedly decreased. The importance of surgical expertise for short- as well as long-term outcome is emphasized. The knowledge of adequate surgery together with the use of combined modalities opens the door to the amelioration of the still dismal prognosis for patients with gastric cancer. This paper reviews the modern approach to gastric cancer using an individualized treatment concept.

Pretransplantation evaluation of the cirrhotic liver with explantation correlation: accuracy of CT arterioportography and digital subtraction hepatic angiography in revealing hepatocellular carcinoma

OBJECTIVE

The aim of this study was to determine the accuracy of CT arterioportography and hepatic digital subtraction angiography, separately and combined, for the detection of hepatocellular carcinoma in the cirrhotic liver by using thin-section liver explant histopathologic findings.

SUBJECTS AND METHODS

Fifty-nine patients with liver cirrhosis were examined with CT arterioportography and digital subtraction angiography as a part of preoperative diagnostic workup for liver transplantation. Before liver explantation, CT arterioportograms and digital subtraction angiograms were prospectively evaluated in a blinded manner, separately by two CT radiologists and two angiographers, respectively, and combined by two reviewer teams, each including a CT radiologist and an angiographer. In addition, each examination was retrospectively evaluated using direct comparison with the corresponding thin-section liver explant specimens

RESULTS

There were 39 histologically confirmed hepatocellular carcinomas. In both prospective and retrospective assessments, the reviewers achieved the best performance with CT arterioportography and digital subtraction angiography combined (area under the curve [A(z)] 0.82). The diagnostic confidence in the detection of hepatocellular carcinoma was higher with digital subtraction angiography (A(z), 0.81) than that with CT arterioportography (A(z), 0.68). Prospectively, sensitivity and specificity were 75% and 60% for CT arterioportography, 77% and 80% for digital subtraction angiography, and 84% and 81% for CT arterioportography and digital subtraction angiography combined, respectively. Retrospectively, sensitivity and specificity were 80% and 62% for CT arterioportography; 82% and 79% for digital subtraction angiography; 87% and 81% for CT arterioportography and digital subtraction angiography combined, respectively. Five hepatocellular carcinomas, one poorly and four well differentiated, with a mean size of 1.4 cm were not detectable on the CT arterioportography and digital subtraction angiography combination. False-positive findings were 20, 11, and 10 on CT arterioportography, digital subtraction angiography, and the CT arterioportography and digital subtraction angiography combination.

CONCLUSION

Combining CT arterioportography with digital subtraction angiography enabled reliable detectability of moderately and poorly differentiated hepatocellular carcinomas in cirrhotic livers but was less sensitive for the detection of well-differentiated hepatocellular carcinomas and resulted in a relatively high rate of false-positive findings.

Poor sensitivity of sonography in detection of hepatocellular carcinoma in advanced liver cirrhosis: accuracy of pretransplantation sonography in 118 patients

The objective of this study was to assess the detectability of hepatocellular carcinoma by sonography in advanced cirrhotic patients undergoing liver transplantation. We retrospectively reviewed pretransplantation sonography in 118 consecutive patients with advanced liver cirrhosis. We assessed the detectability of hepatocellular carcinoma in relation to tumor size, location, total liver volume, and degree of sonographic heterogeneity of the liver parenchyma. On pathologic examination, 51 hepatocellular carcinomas were identified in 31 patients. Pretransplantation sonography depicted 14 of 51 (27%) hepatocellular carcinomas. Detectability was significantly affected according to tumor size ( p=0.0099), but there was no significant difference according to tumor location, liver volume, or degree of sonographic heterogeneity of the liver parenchyma. Our study suggests that sonography is not sufficiently sensitive to detect hepatocellular carcinoma in patients with advanced liver cirrhosis. Tumor size is the only factor influencing the detectability of hepatocellular carcinoma.

Nondysplastic nodules that are hyperintense on T1-weighted gradient-echo MR imaging: frequency in cirrhotic patients undergoing transplantation

OBJECTIVE

Our objective was to determine the frequency and MR imaging findings of nondysplastic nodules that are hyperintense on T1-weighted gradient-echo imaging in patients with cirrhosis who undergo liver transplantation.

MATERIALS AND METHODS

Two observers retrospectively evaluated in-phase (4-5 msec), opposed-phase gradient-echo (2.0-2.4 msec), and turbo short tau inversion recovery (STIR) MR images in 68 patients with cirrhosis--but without dysplastic nodules or hepatocellular carcinoma--who underwent MR imaging at 1.5 T within 150 days before liver transplantation. The size, number, signal characteristics, and arterial enhancement pattern of nodules that appear hyperintense on T1-weighted gradient-echo images were evaluated as well as the presence or absence of signal loss on opposed-phase imaging. These imaging findings were correlated with pathologic findings of whole explanted livers.

RESULTS

Eleven (16%) of 68 patients had at least one nondysplastic nodule that was hyperintense on T1-weighted MR imaging. Three patients had diffuse nondysplastic hyperintense nodules (>10 nodules) measuring less than 0.5 cm, and the remaining eight patients had 22 nondysplastic hyperintense nodules ranging in size from 0.5 to 2.5 cm (mean, 1.2 cm), of which 13 were isointense and nine were hypointense on turbo STIR images. No lesion lost signal on opposed-phase imaging or enhanced during the hepatic arterial phase.

CONCLUSION

In cirrhotic patients undergoing liver transplantation, nondysplastic nodules that are hyperintense are common findings on T1-weighted gradient-echo MR imaging and do not lose signal intensity on opposed-phase imaging or enhance during the hepatic arterial phase. These nodules may be indistinguishable from dysplastic nodules.

Hepatocellular carcinoma in cirrhotic livers: double-contrast thin-section MR imaging with pathologic correlation of explanted tissue

OBJECTIVE

The aim of our study was to determine the sensitivity of double-contrast MR imaging in the detection of hepatocellular carcinomas in patients with a cirrhotic liver.

SUBJECTS AND METHODS

Thirty-one patients underwent double-contrast MR imaging and subsequent liver transplantation. Breath-hold T1- and T2-weighted MR images were obtained before and after administration of superparamagnetic iron oxide, and three-dimensional T1-weighted gradient-recalled echo MR images were obtained 10, 40, and 120 sec after a bolus injection of gadolinium. Hypervascular lesions that failed to take up superparamagnetic iron oxide were regarded as showing typical characteristics of hepatocellular carcinoma; lesions that had only one of these two characteristics (either hypervascularity or failure to take up superparamagnetic iron oxide) were regarded as highly suspicious for hepatocellular carcinoma. Radiology reports were correlated with pathology reports for the explanted livers.

RESULTS

Thirty-two hepatocellular carcinomas were found in 14 of the 31 patients. Combining the number of MR imaging reports citing lesions that were "typical of hepatocellular carcinoma" with the number of those citing lesions that were "highly suspicious," we found that for 25 of 32 lesions, an accurate MR imaging diagnosis of hepatocellular carcinoma was made (overall sensitivity, 78%). These lesions included 10 of the 11 lesions that were larger than 20 mm (sensitivity, 91%), 12 of the 13 lesions that were 11-20 mm (sensitivity, 92%), and three of the eight lesions that were 10 mm or less (sensitivity, 38%). Nineteen (76%) of 25 lesions had characteristics considered typical of hepatocellular carcinoma; the remaining six lesions either failed to take up superparamagnetic iron oxide and were hypovascular or were hypervascular but showed some uptake of superparamagnetic iron oxide.

CONCLUSION

In patients with a cirrhotic liver, double-contrast MR imaging is highly sensitive in the diagnosis of hepatocellular carcinomas of 10 mm or larger, but success in the identification of tumors smaller than 10 mm is still limited.

Screening for hepatocellular carcinoma: why, when, how?

Hepatocellular carcinoma (HCC) is a major public health concern in many areas of the world, and its incidence is increasing in the United States and other countries. Screening for HCC in patients with cirrhosis has been advocated to identify those with small lesions who would benefit from transplantation or surgical resection. Despite these recommendations, several issues regarding screening remain controversial. No randomized, controlled trials have confirmed that surveillance for HCC reduces disease-specific mortality. In addition, the most appropriate screening test and optimal screening interval have not yet been defined. Clearly, these unresolved questions have a major impact on the cost-effectiveness of a screening program either at the population or the clinic level. A few studies, however, have suggested that screening may be cost-effective because a minor survival benefit could result in a cost that is acceptable to decision makers.

Transplantation for hepatocellular carcinoma and cirrhosis: sensitivity of magnetic resonance imaging

The sensitivity of magnetic resonance imaging (MRI) in patients who undergo transplantation for hepatocellular carcinoma (HCC) and cirrhosis is not known. We prospectively evaluated 24 patients with known HCC who underwent MRI and subsequent transplantation within 60 days (mean, 20 days). Using a phased-array coil at 1.5T, breath-hold turbo STIR and T2-weighted MR images were performed. Dynamic gadolinium-enhanced MRI was performed using a two- or three-dimensional gradient echo pulse sequence with images obtained in the hepatic arterial, portal venous, and equilibrium phases. The prospective interpretation of the MR study was directly compared with thin-section pathology evaluation of the explanted livers. All 24 patients had at least one HCC, and MR diagnosed tumor in 21 (88%) of these patients. On a lesion-by-lesion basis, MRI depicted 39 of 118 HCC for an overall sensitivity of 33%. MRI detected five (100%) of five lesions >5 cm, 20 (100%) of 20 lesions >2 cm but not exceeding 5 cm, 11 (52%) of 21 lesions between 1 and 2 cm, and three (4%) of 72 lesions <1 cm. Of the nine patients with carcinomatosis (innumerable lesions less than 1 cm), MR detected three lesions in one patient. Of the 15 dysplastic nodules found at pathology, MRI depicted a single 1.8-cm high-grade lesion, for a sensitivity of 7%. In conclusion, MRI is sensitive for the detection of HCC measuring at least 2 cm in diameter but is insensitive for the diagnosis of small HCC (<2 cm) and carcinomatosis.

Preoperative evaluation of patients awaiting liver transplantation: comparison of multiphasic contrast-enhanced 3D magnetic resonance to helical computed tomography examinations

PURPOSE

To determine the feasibility of using a multiphasic magnetic resonance (MR) examination to evaluate the hepatic arterial anatomy and parenchyma in patients awaiting orthotopic liver transplantation (OLT).

MATERIALS AND METHODS

Twenty consecutive patients awaiting OLT underwent multiphasic MR (using a T1-weighted 3D gadolinium-enhanced gradient-echo (GRE) sequence and two separate injections of contrast material) and computed tomography (CT) imaging; both imaging studies were performed within a 1-week period for each patient. Quantitative and qualitative assessment of the hepatic arterial system on MR data was performed. Two independent observers classified the hepatic arterial anatomy and evaluated the hepatic parenchyma from the MR data. The prospective CT interpretation was used as the gold standard.

RESULTS

Overall qualitative rating of hepatic arterial system-to-background contrast on MR data was good to excellent (average pooled score of 2.00 +/- 0.27), with no significant difference between the two observers after the first or second injections of contrast material. Classification of hepatic arterial anatomy by MR angiography (MRA) and CT angiography (CTA) was concordant in 85% (17/20) of patients and discordant in 15% (3/20) of patients. Focal parenchymal lesions were detected in 25% (5/20) of patients by MR and CT; however, two lesions in one patient with multiple lesions were detected only with MR.

CONCLUSION

Multiphasic T1-weighted 3D gadolinium-enhanced MR examination can provide comprehensive evaluation of the hepatic arterial anatomy and parenchyma in patients awaiting OLT. MR may offer an advantage over CT in the detection of focal parenchymal lesions.

Focal lesions in cirrhotic explant livers: pathological evaluation and accuracy of pretransplantation imaging examinations

Imaging detection and diagnosis of hepatocellular carcinomas (HCCs) and dysplastic nodules (DNs) in cirrhotic patients is important because the number, size, and type of focal lesions strongly influence patient management. Focal lesions detected by imaging examinations during pretransplantation evaluation were correlated with focal lesions detected during detailed pathological examination of 49 cirrhotic explant livers. Within 6 months before transplantation, color Doppler ultrasonography (US), contrast-enhanced computed tomography (CT), and magnetic resonance (MR) imaging were performed in 94%, 33%, and 55% of patients, respectively. In 2% to 8% of patients, different types of benign focal lesions were present, and a considerable proportion was interpreted as (pre)malignant on imaging examination. US detected only the largest HCCs (patient sensitivity, 40%; specificity, 100%) and no DNs. On a per-patient basis, contrast-enhanced CT and MR imaging had poor sensitivity (20% and 27%, respectively) and good specificity (100% and 94%, respectively) for DNs. Patient sensitivity and specificity of both techniques for HCC were reasonable (50% for CT, 70% for MR imaging) and good (79% for CT, 82% for MR imaging), respectively. Neither technique was able to detect smaller (pre)malignant lesions. As a consequence, 10% of patients underwent transplantation, although they exceeded the tumor number limit. Currently used imaging techniques cannot correctly determine the exact tumor burden in some cirrhotic patients. Regular contrast-enhanced MR examination of cirrhotic patients waiting for liver transplantation is the best tool for the early detection of (pre)malignant lesions.

Double arterial phase dynamic MRI with sensitivity encoding (SENSE) for hypervascular hepatocellular carcinomas

PURPOSE

To investigate the efficacy of SENSE MRI, including the double arterial phase dynamic study, to detect hypervascular hepatocellular carcinomas (HCCs).

MATERIALS AND METHODS

MRI of the liver was performed in 40 consecutive patients (20 by conventional MRI and 20 by SENSE MRI). The SENSE technique was used to obtain breath-hold T1-weighted FSE images (TR/TE = 556/12 msec), respiratory-triggered T2-weighted FSE images (TR/TE = 1800/90 msec) with and without fat suppression, and dynamic MR images (TR/TE/FA = 160-168/4.6 msec/70 degrees ). In each arterial dominant phase and portal dominant phase, two scans were consecutively performed with one breath-hold, leading to the double arterial phase and double portal phase images with SENSE.

RESULTS

The sensitivity of SENSE MRI for HCCs diagnosed from all MR images, including dynamic study, T1-weighted images, and T2-weighted images, was 91.7%, while that of conventional MRI was 76.3%. The positive predictive value of SENSE MRI for HCCs was 91.7%, while that of conventional MRI was 87.9%. In terms of HCCs < or = 10 mm, the sensitivity and positive predictive values of SENSE MRI were 78.6% and 78.6%, respectively, while those of conventional MRI were 27.3% and 60.0%, respectively. The number of detected HCCs < or = 10 mm was significantly larger in SENSE MRI than in conventional MRI (P < 0.05). The cause of false-positive lesions on SENSE MR images was an arterioportal shunt.

CONCLUSION

SENSE MRI with double arterial phase dynamic study showed higher sensitivity compared to the conventional technique. Therefore, SENSE MRI is a promising method for the detection of HCC.

Sonographic detection of hepatocellular carcinoma and dysplastic nodules in cirrhosis: correlation of pretransplantation sonography and liver explant pathology in 200 patients

OBJECTIVE

The objective of this study was to determine the sensitivity and specificity of sonography as an aid in detecting hepatocellular carcinomas and dysplastic nodules using explantation correlation in patients with cirrhosis and no known hepatocellular carcinomas.

MATERIALS AND METHODS

The sonography reports of 200 patients with cirrhosis who underwent sonography and then underwent liver transplantation within 90 days were retrospectively reviewed for focal solid liver lesions. All focal solid masses detected on sonography were considered possible hepatocellular carcinomas. The sonographic findings were compared with thin-section explanted liver pathologic results.

RESULTS

Twenty-seven patients (13.5%) had hepatocellular carcinoma at explantation, including four patients with diffuse, multifocal tumors. Eight of the 39 lesions were detected on sonography for a patient sensitivity of 29.6% and a lesion sensitivity of 20.5%. Sonography revealed three (75%) of four hepatocellular carcinomas larger than 5 cm in diameter, one (50%) of two hepatocellular carcinomas with diameters of 3.1-5.0 cm, one (20%) of five hepatocellular carcinomas with diameters of 2.1-3.0 cm, three (13.6%) of 22 hepatocellular carcinomas with diameters of 1-2 cm, and no lesions with diameters smaller than 1 cm. Forty-two patients (21%) had a total of 126 dysplastic nodules including two patients with innumerable lesions. Sonography depicted only two dysplastic nodules, for a patient sensitivity of 4.8% and a lesion sensitivity of 1.6%. The overall specificity of sonography for either hepatocellular carcinomas or dysplastic nodules was 96%.

CONCLUSION

Sonography has low sensitivity but high specificity in revealing hepatocellular carcinomas and dysplastic nodules in patients with a cirrhotic liver requiring liver transplantation. In these patients, sonography should not be the sole imaging modality used for lesion detection before transplantation.

Hepatocellular carcinoma: predisposing conditions and precursor lesions

The global incidence of HCC is rising; in the United States, its rise is in parallel to that of cirrhosis due to the HCV and obesity epidemics. The lack of adequate treatment for advanced HCC mandates both prevention and early detection of these lesions. The limitations of currently available histopathologic evaluations, serologic markers, and radiographic imaging modalities in detecting HCC and its precursors have been outlined in this review. Refinements of all of these may lead to better HCC detection, earlier intervention, and successful treatment. Randomized controlled trials are necessary to evaluate the most efficacious and cost-effective approach to screening.

MR contrast agents in hepatic cirrhosis and chronic hepatitis

Chronic liver disease alters the gross architecture of the liver and its arterial and portal blood supply. The relative proportion of regenerative hepatocytes, necrosis, extracellular interstitial space, and fibrosis is responsible for liver enhancement after the administration of a contrast agent. Because contrast agents can be directed toward either the extracellular or the intracellular spaces, knowledge of the different parenchymal enhancement alterations seen after the administration of these agents is necessary to understand how chronic liver disease pathologic changes influence contrast-enhanced magnetic resonance (MR) images. This article reviews the effect of chronic liver disease on MR contrast enhancement, as well as the effect of altered enhancement on lesion detection and characterization. Both extracellular and intracellular contrast agents are considered.

Fluorine-18 FDG imaging in hepatocellular carcinoma using positron coincidence detection and single photon emission computed tomography

BACKGROUND/AIMS

We prospectively evaluated whether fluorine-18 deoxyglucose (FDG) positron coincidence detection (PCD) or FDG single-photon emission computed tomography (SPECT) provides additional benefits to our conventional preoperative evaluation of lesion detection in patients suspected to have hepatocellular carcinoma (HCC).

METHODS

Thirteen consecutive patients with a suspected HCC underwent conventional preoperative evaluation with ultrasonography (US), triple-phase helical computed tomography (CT), superparamagnetic iron oxides (SPIO) enhanced magnetic resonance imaging (MRI) and serum alpha-fetoprotein (AFP) level. All 13 patients had an FDG-PCD and SPECT. These results were evaluated to assess the value of FDG-PCD and SPECT in addition to US, SPIO-enhanced MRI and triple-phase helical CT.

RESULTS

Ten of the 13 (77%) patients had at least one histologically confirmed HCC without extrahepatic abdominal spread. The tumors ranged in size from 1 to 8 cm and the serum AFP ranged from 3 to 30 000 microg/l. Of these 10 patients, two patients had an increased tumor F-FDG uptake (sensitivity of 20%); one patient with an AFP of 5 microg/l and a tumor size of maximum 4.5 cm and one patient with an AFP of 249 microg/l and a tumor size of maximum 2 cm. In three patients with a benign liver mass, FDG imaging with either PCD or SPECT was negative. There was no false positive finding.

CONCLUSIONS

We found poor sensitivity of FDG-PCD and FDG-SPECT for the detection of HCC. There were no clear relations between AFP or tumor size and FDG uptake. Therefore, we conclude that FDG imaging with PCD or SPECT has no value in the preoperative work-up for HCC in patients with cirrhosis.

Impact of multidetector CT hepatic arteriography on the planning of chemoembolization treatment of hepatocellular carcinoma

OBJECTIVES

We examined the impact of the increased sensitivity for hypervascular masses of multidetector CT hepatic arteriography on treatment decisions involving selective chemoembolization of hepatocellular carcinomas.

SUBJECTS AND METHODS

Thirty patients were referred for chemoembolization of unresectable hepatocellular carcinoma. Initial selective chemoembolization plans were formulated on the basis of diagnostic biphasic CT or MR imaging. Ultrafast CT hepatic arteriography was performed using a multidetector CT scanner and selective contrast material injection into the hepatic artery. The entire liver was scanned in a single breath-hold of approximately 20 sec with a slice thickness of 1 mm. Lesions and their arterial supplies were identified, and these data were immediately used to formulate a final plan for chemoembolization.

RESULTS

Hypervascular masses were detected in 29 patients. In 16 (53%) of the patients, preprocedural CT or MR imaging underestimated the number of lesions. In nine (30%) of these 16 patients, the additional lesions were detected only on CT hepatic arteriography, not on conventional angiography. CT hepatic arteriography findings had a major impact on planning the way in which chemoembolization treatment was performed. In three of the nine patients, the previously undetected lesions were treated with additional superselective chemoembolization. In the other six patients, chemoembolization was performed less selectively than originally planned.

CONCLUSION

Primarily because of the high sensitivity of multidetector CT hepatic arteriography in revealing small and multifocal hepatomas, findings of this modality frequently alter treatment plans involving selective administration of chemoembolic material.