Aberrant gastric venous inflow to the left lobe of the liver parenchyma adjacent to the falciform ligament

Direct inflow of the aberrant right gastric vein independent of the portal venous system to the liver parenchyma is a well known cause of non-tumorous abnormalities on CT angiography. However, there have been no previous reports of aberrant gastric venous drainage as the cause of non-tumorous abnormalities in the left lobe of the liver parenchyma adjacent to the falciform ligament on CT angiography. We present a case of direct inflow of an aberrant gastric vein to this region of the liver, which influenced the non-tumorous enhancement shown by CT hepatic arteriography.     

Diagnosis of hepatic neoplasms using CT arterial portography and CT hepatic arteriography

Both computed tomography arterial portography (CTAP) and CT hepatic arteriography (CTHA) are CT techniques with angiographic assistance. The detection sensitivity of these techniques is high because marked lesion contrast can be obtained using direct delivery of contrast materials to the liver parenchyma or the tumors. The use of CTAP and CTHA may improve therapeutic results after transarterial embolization therapy for hepatocellular carcinomas because of their high diagnostic accuracy. Findings on CTAP or CTHA can sometimes help characterize the hepatic focal lesions. Thus, CTAP and CTHA are frequently performed as pretreatment examinations, although they are invasive compared to intravenous (IV) contrast-enhanced CT or magnetic resonance imaging. However, there are some potential pitfalls, such as nontumorous perfusion abnormalities. CTAP and CTHA are less effective for evaluation of patients with cirrhosis and portal hypertension. This article presents a current overview of CTAP and CTHA technique for diagnosis of hepatic neoplasms.     

Non-tumorous enhancement caused by cholecystic venous inflow shown on biphasic CT hepatic arteriography: comparison with hepatocellular carcinoma

The haemodynamics in non-tumorous abnormalities on CT arterial portography (CTAP) owing to cholecystic venous direct inflow to the liver were compared with the haemodynamics in hepatocellular carcinoma. 53 patients who simultaneously underwent CTAP and CT during hepatic arteriography (CTHA) to detect hepatocellular carcinoma had the late phase added to CTHA. Changes in size, shape and pattern of 47 non-tumorous enhancement abnormalities on the liver around the gall bladder or in the dorsum of segment IV between the early and late phases on biphasic CTHA as well as of 60 tumorous lesions were determined. Enhancement on biphasic CTHA was seen in all 47 lesions with a non-tumorous portal defect (early phase alone, n=8; late phase alone, n = 3; both, n = 36). In these 47 lesions, the size and the shape of enhancement changed in 63.8% and 51.1%, respectively, between the early and late phases on CTHA; the pattern of enhancement did not change in 72.3%. On the other hand, the size of enhancement on biphasic CTHA changed in only 16.7% of 60 tumours, and the shape in only 5%, although the enhancement pattern changed in a large proportion (80%). In conclusion, owing to the difference in haemodynamics, non-tumorous abnormalities caused by cholecystic venous inflow and tumours are clearly delineated on biphasic CTHA. Thus, adding the late phase to previous single phase CTHA (i.e. performing biphasic CTHA) is useful in differentiating the two entities.     

Diffuse perfusion abnormality of the liver parenchyma on angiography-assisted helical CT in relation to cirrhosis and previous treatments: a potential diagnostic pitfall for detecting hepatocellular carcinoma

We evaluated diffuse perfusion abnormality of the liver parenchyma in relation to cirrhosis and previous treatments and estimated its potential limitation in detecting hepatocellular carcinomas (HCCs) on CT arterial portography (CTAP) and CT hepatic arteriography (CTHA). Sixty-one patients of liver cirrhosis with or without HCC received both CTAP and CTHA. Irregular defects of enhancement of the liver parenchyma on CTAP were noted in 37 of 61 patients (60.7%) and compensatory arterial perfusion in these defects on CTHA was noted in 30 of 37 patients (81.1%). Most patients had segmental or mixed patterns of enhancement. In patients with severe cirrhosis, irregular enhancement was often noted. The irregularity was also more often in patients who had had previous treatments. Four of 40 HCC nodules in 18 patients with severe irregular perfusion were not detected on CTAP and CTHA. Diffuse perfusion abnormalities of the liver parenchyma on CTAP and CTHA would decrease the accuracy of tumor detection in HCC patients.     

Pre-operative detection of malignant hepatic tumours: value of combined helical CT during arterial portography and biphasic CT during hepatic arteriography

AIMS: The purpose of our study was to evaluate the observer performance with combined helical CT during arterial portography (CTAP) and biphasic CT hepatic arteriography (CTHA) in the pre-operative detection of malignant hepatic tumours. METHODS: Computed tomography images obtained in 41 patients with suspected hepatic tumours were retrospectively reviewed. In a blind fashion, three off-site, independent radiologists reviewed CTAP and early-phase CTHA combined for the first review, then late-phase CTHA was added for the second review. Statistical analysis was conducted on lesion-by-lesion and segment-by-segment bases; a total of 328 liver segments including 65 segments with 74 malignant hepatic tumours ranging in size from 5 to 100 mm (mean, 21.4 mm) were analysed. RESULTS: Sensitivity for detection of liver segments harbouring tumours of CTAP and biphasic CTHA combined (82%) was identical to that of CTAP and early-phase CTHA combined (82%). Specificity of CTAP and biphasic CTHA combined (93%) was greater than that of CTAP and early-phase CTHA combined (90%, P < 0.005). The mean confidence level for the 74 tumours significantly increased by adding late-phase CTHA (P < 0.0005). The mean confidence level for 100-142 benign perfusion abnormalities detected with CTAP and early-phase CTHA combined significantly decreased by adding late-phase CTHA (P < 0.0005). CONCLUSION: By combining late-phase CTHA with CTAP and early-phase CTHA information, the specificity for the detection of malignant hepatic tumours rises significantly, allowing more accurate preoperative tumour detection.     

CT during hepatic arteriography and portography: an illustrative review.

The combination of computed tomography (CT) during arterial portography (CTAP) and CT during hepatic arteriography (CTHA) has been used for evaluation of hepatic neoplasms before partial hepatic resection. Focal hepatic lesions that can be demonstrated with CTAP and CTHA include regenerative nodules, dysplastic nodules, dysplastic nodules with malignant foci, hepatocellular carcinoma, cholangiocarcinoma, hemangioma, and metastases. CTAP is considered the most sensitive modality for detection of small hepatic lesions, particularly small hepatic tumors such as hepatocellular carcinoma and metastatic tumors. CTHA can demonstrate not only hypervascular tumors but also hypovascular tumors and can help differentiate malignant from benign lesions. However, various types of nontumorous hemodynamic changes are frequently encountered at CTAP or CTHA and appear as focal lesions that mimic true hepatic lesions. Such hemodynamic changes include several types of arterioportal shunts, liver cirrhosis, Budd-Chiari syndrome, inflammatory changes, pseudolesions due to an aberrant blood supply, and laminar flow in the portal vein. Familiarity with the CTAP and CTHA appearances of various hepatic lesions and nontumorous hemodynamic changes allows the radiologist to improve the diagnostic accuracy.     

Diagnostic accuracy of helical CT arterial portography and CT hepatic arteriography for hypervascular hepatocellular carcinoma in chronic liver damage. An ROC analysis

PURPOSE: To evaluate the detectability of hypervascular hepatocellular carcinomas (HCCs) in chronic liver damage with helical CT arterial portography (CTAP) and CT hepatic arteriography (CTHA). MATERIAL AND METHODS: Thirty-nine HCC patients who underwent CTAP and CTHA were studied. Diagnostic abilities of CTAP alone, CTHA alone, or combined CTAP and CTHA were evaluated by receiver operating characteristic (ROC) analysis. Fifty-three images with 53 HCC nodules were evaluated. Tumor size ranged from 5 to 90 mm (mean 22.8 mm). Sensitivities and specificities for all techniques were calculated. RESULTS: ROC analysis showed the diagnostic ability significantly better with combined CTAP and CTHA (mean area under the ROC curve (Az)=0.95), or CTHA alone (Az=0.93) than CTAP alone (Az=0.87) (p<0.01). Combined CTAP and CTHA showed the best sensitivity (95.0%), followed by CTHA alone (88.1%) and CTAP alone (85.5%). The specificities of all three imaging techniques were relatively low (54.1% for combined CTAP and CTHA, 71.1% for CTHA alone, and 54.1% for CTAP alone) because of perfusion abnormalities of the liver parenchyma. CONCLUSION: The combination of CTAP and CTHA is superior to CTAP alone for detection of hypervascular HCCs. However, its specificity was relatively low in chronic liver damage.     

Pseudolesions of left liver lobe during helical CT examinations: prevalence and comparison between unenhanced and biphasic CT findings

OBJECTIVE: Localized low attenuated areas (pseudolesions) in the medial segment of left liver lobe are not rarely seen in the screening of abdomen using helical CT. The purpose of this study was to determine the prevalence of pseudolesions in the routine helical CT of abdomen and to evaluate the morphologic and enhancement features of pseudolesions in the unenhanced and enhanced CT examinations. MATERIALS AND METHODS: We retrospectively evaluated 333 contrast enhanced abdominal CT examination of 328 patients with no known liver disease, to detect the presence of pseudolesion of liver. In the presence of unenhanced and arterial phase examinations, these images were also analyzed. The imaging criteria for pseudolesion of liver was localized low attenuated area with geometric, ovoid or nodular shaped and with no mass effect adjacent to the falciform ligament, gallbladder, or porta hepatis. Previous CT, CTAP and MR examinations were also reviewed to understand the evolution of pseudolesion in patients in whom a pseudolesion was detected in the portal phase of helical CT examination. RESULTS: We identified a pseudolesion in the 65 (19.8%) of 328 patients in portal phase of helical CT examinations. Pseudolesions were identified in the medial segment of left liver lobe adjacent to falciform ligament in the 92.8% of patients, both sides of falciform ligament in the 1.5% of patients, adjacent to porta hepatis in the 3% of patients and adjacent to gallbladder 3% of patients. These lesions had triangular shape in the 66.1% of patients, ovoid shape in the 18.6% of patients, and nodular shape in the 15.3% of patients. Unenhanced, arterial and portal phase images were exist in the 50.7% of 65 patients. The pseudolesions were not identified on the unenhanced images in the 75.7% of patients and on the arterial phase images in the 55.6% of patients. CONCLUSION: Pseudolesions around the falciform ligament are not rarely seen in the routine helical CT examination of liver and abdomen. The pseudolesions are more encountered in the portal phase of helical CT examination. These lesions seem to be likely focal fatty infiltration or perfusion defect due to venous supply variation or both. Nodular shaped pseudolesions may be interpreted as true tumors and further study may require for differential diagnosis.     

Hepatic arterioportal shunts not directly related to hepatocellular carcinoma: findings on CT during hepatic arteriography, CT arterial portography and dual phase spiral CT

AIM: To evaluate findings of arterioportal shunts not directly related to hepatocellular carcinoma (HCC) which were seen within third-order portal branches on computed tomography (CT) during hepatic arteriography (CTHA), arterial portography (CTAP), and dual phase spiral CT.MATERIALS AND METHODS: At CTHA in 112 patients, we examined third-order portal vein branches to find arterioportal shunts not directly related to HCC. Six cases were found. We evaluated the findings of these shunts on CTHA and investigated whether CTAP (n = 6) and dual phase spiral CT (n = 5) showed perfusion defects in the corresponding areas on arterioportal shunts. RESULTS: Five of six cases showed abrupt visualization of portal branches without visualization of the proximal portion of CTHA. Five of six cases showed no perfusion defect on CTAP and no hyperattenuating area on CTHA. Four of five cases showed no hyperattenuating area on hepatic arterial phase spiral CT. CONCLUSION: Arterioportal shunts not directly related to HCC and occuring within third-order portal branches mainly showed abrupt visualization of portal branches on CTHA. These occurred frequently without perfusion defects on CTAP and without a hyperattenuating area on CTHA and hepatic arterial phase spiral CT.Park, C. M. (2000). Clinical Radiology55, 465-470.     

CT during arterial portography: effects of precontrast injection of prostaglandin E1 into the superior mesenteric artery

Prostaglandin E1 (PGE1) is a vasodilator that increases portal venous flow. Hepatic CT during arterial portography (CTAP) was performed in 42 patients with and without PGE1 to compare peak hepatic enhancement and nontumorous abnormalities. Although no significant differences in peak hepatic enhancement were observed (71 +/- 12 HU for CTAP with PGE1; 74 +/- 34 HU for CTAP without PGE1), the number of nontumorous abnormalities for CTAP with PGE1 (n = 11) was significantly lower than that for CTAP without PGE1 (n = 24) (p < 0.01, Wilcoxon signed rank test). CTAP combined with PGE1 therefore represents a useful method to study lesions of the liver, as the number of nontumorous abnormalities observed is significantly reduced and liver parenchyma can be scanned more evenly.     

The aetiology of non-tumorous enhancement in the hepatic hilum shown on CT hepatic arteriography

The causes of non-tumorous abnormalities in the hepatic hilum seen on CT hepatic arteriography were investigated. 13 patients with non-tumorous defects of portal perfusion in the hepatic hilum on CT arterial portography underwent both CT hepatic arteriography from the common hepatic artery and CT obtained during proper hepatic arteriography. The findings of non-tumorous portal defects on these two angiographic studies using helical CT were compared. In the 13 patients, 14 non-tumorous defects of portal perfusion in the hepatic hilum on CT arterial portography were detected as enhanced areas in 10 regions (dorsum of segment IV, 7/10; dorsum of the lateral segment, 3/4) on CT hepatic arteriography via the common hepatic artery, but none were enhanced on CT obtained during proper hepatic arteriography. In conclusion, the main cause of non-tumorous enhancement in the hepatic hilum seen on CT hepatic arteriography is non-portal direct inflow via the parabiliary venous system.     

Correlation of a defect of portal perfusion in the dorsal part of segment IV of the liver on CT arterial portography with inflow of the aberrant pancreaticoduodenal vein

The correlation between an aberrant pancreaticoduodenal vein and a portal perfusion defect in the dorsal part of segment IV as demonstrated on CT arterial portography (CTAP) was investigated. 14 patients with non-tumorous defects of portal perfusion in the dorsal part of segment IV of the liver parenchyma, shown on CTAP underwent CT during pancreaticoduodenal arteriography. The defect on CTAP was shown as an enhanced area resulting from non-portal venous inflow in eight (57%) of 14 patients on CT during pancreaticoduodenal arteriography. In conclusion, the non-portal venous supply via an aberrant pancreaticoduodenal vein occasionally causes a defect of portal perfusion in the dorsal part of segment IV on CT arterial portography.     

肝动脉和经动脉门脉造影螺旋CT联合应用对肝癌的诊断价值

目的　探讨螺旋CT扫描在肝动脉造影CT(CTHA)和经动脉门脉造影CT(CTAP)对肝癌的诊断价值。方法　分析 2 1例肝癌病人CTAP和CTHA图像 ,并与螺旋CT三期增强扫描进行对照。结果　三期增强扫描病灶检出率为 72 .4% (5 5 /76) ;CTAP病灶检出率为 96.1% (73 /76) ;CTHA病灶检出率为 88.2 % (67/76) ;CTAP和CTHA联合应用病灶检出率为 98.7% (75 /76) ,可检出 0 .5cm的微小癌灶。CTAP和CTHA均可出现非病理性表现 ,CTAP灌注异常出现率为 2 2 .3 % ,CTHA非病理性强化灶出现率为 3 0 .2 %。结论　螺旋CT动脉造影能显著减少造影剂用量 ,提高图像质量 ,CTAP和CTHA联合应用肝癌病灶检出率明显高于CT三期增强扫描。CTAP和CTHA结合分析可减少假阳性率。     

Regenerative nodules in liver cirrhosis: findings at CT during arterial portography and CT hepatic arteriography with histopathologic correlation

PURPOSE: To determine the appearance of regenerative nodules in patients with liver cirrhosis at computed tomography (CT) during arterial portography (CTAP) and CT hepatic arteriography (CTHA). MATERIALS AND METHODS: CTAP and CTHA of the liver were performed in 28 consecutive patients with hepatocellular carcinoma (HCC) who were scheduled to undergo partial resection of the liver. Helical CTAP was performed after contrast material injection into the superior mesenteric artery followed by helical CTHA after contrast material injection into the hepatic artery. CT scans were analyzed for the presence of identifiable nodules and their size; results were correlated with gross and microscopic findings. RESULTS: Resected livers showed cirrhosis in 20 patients, chronic hepatitis in four, and normal liver in four. Among the 20 patients with cirrhosis, regenerative nodules were demonstrated as enhancing 3-10 mm nodules surrounded by lower attenuation fibrous septa 0.8-1.5 mm thick at CTAP in seven patients and nonenhancing nodules of the same size surrounded by enhancing fibrous septa at CTHA in 15 patients. The degree of fibrosis determined the conspicuity of nodules. CONCLUSION: Regenerative nodules in cirrhotic liver are visualized as enhancing nodules surrounded by lower attenuation thin septa at CTAP and nonenhancing nodules surrounded by enhancing fibrous septa at CTHA. CTHA is more sensitive than CTAP in depicting regenerative nodules (P < .005).     

Preoperative detection of malignant hepatic tumors: comparison of combined methods of MR imaging with combined methods of CT

OBJECTIVE: We compared radiologists' performance on combined unenhanced, gadolinium-enhanced, and ferumoxides-enhanced MR imaging with their performance on helical CT during arterial portography (CTAP) and biphasic CT during hepatic arteriography (CTHA) for the preoperative detection of malignant hepatic tumors. SUBJECTS AND METHODS: MR images and CT scans obtained in 33 patients were retrospectively analyzed. Images of the liver were reviewed on a segment-by-segment basis; a total of 261 segments with 39 hepatocellular carcinomas and 21 metastases were independently reviewed by three radiologists who were invited from outside institutions. Unenhanced and gadolinium-enhanced MR images were reviewed first, then ferumoxides-enhanced MR images were added for combined review. CTAP images and biphasic CTHA images were reviewed together. RESULTS: Sensitivity for the detection of hepatic tumors was analogous for combined unenhanced, gadolinium-enhanced, and ferumoxides-enhanced MR images (86%) and for combined CTAP images and biphasic CTHA images (87%). Specificity was higher with MR images (95%, p < 0.01) than with CT images (91%). Radiologists' performances were improved (Az = 0.962, p = 0.0502) by combining ferumoxides-enhanced MR images with unenhanced and gadolinium-enhanced MR images (Az = 0.950), and were analogous for combined unenhanced, gadolinium-enhanced, and ferumoxides-enhanced MR images and for combined CTAP images and biphasic CTHA images (Az = 0.959). CONCLUSION: Radiologists' performances on combined unenhanced, gadolinium-enhanced, and ferumoxides-enhanced MR imaging compared with their performances on combined helical CTAP and biphasic CTHA are analogous for the preoperative detection of malignant hepatic tumors. Such a dedicated combination of MR imaging may obviate the need for more invasive angiographically assisted helical CT for the preoperative detection of malignant hepatic tumors.     

Hepatic falciform artery. Angiographic findings in 25 patients

Purpose: To determine the frequency of hepatic falciform artery (HFA) occurrence on celiac or hepatic angiograms and elucidate the anatomy and clinical importance.Material and Methods: Among 1,250 patients who underwent celiac or hepatic arteriography, we encountered 25 patients (2%) with a HFA. Prospectively, CT hepatic falciform arteriography (CTHA) was performed in 4 patients. Indigocarmine dye was injected into the HFA in 6 patients to evaluate whether the abdominal skin was stained. Embolization of the HFA before chemoembolization for hepatocellular carcinoma was performed in 4 patients to prevent abdominal wall injury.Results: Among 25 patients, the HFA arose as a terminal branch of the middle hepatic artery in 14 patients (56%) and of the left hepatic artery in 11 patients (44%). The vessel was single in 18 patients (72%) and double in 7 patients (28%). Two vessels ran side by side along the hepatic falciform ligament. On CTHA, the HFA ran within the hepatic falciform ligament and the branches were connected with the liver around the hepatic falciform ligament. After indigocarmine dye injection, the stain of abdominal skin was recognized in all 6 patients. No abdominal wall injury occurred in any of the 4 patients who were subjected to hepatic chemoembolization.Conclusion: HFA is an extrahepatic pathway which runs to the abdominal wall. Before chemoembolization of the middle or left hepatic artery for hepatic malignancy, the HFA should be recognized.     

Change in Imaging Findings on Angiography-Assisted CT During Balloon-Occluded Transcatheter Arterial Chemoembolization for Hepatocellular Carcinoma

Purpose

To evaluate changes in imaging findings on CT during hepatic arteriography (CTHA) and CT during arterial portography (CTAP) by balloon occlusion of the treated artery and their relationship with iodized oil accumulation in the tumor during balloon-occluded transcatheter arterial chemoembolization (B-TACE).

Methods

Both B-TACE and angiography-assisted CT were performed for 27 hepatocellular carcinomas. Tumor enhancement on selective CTHA with/without balloon occlusion and iodized oil accumulation after B-TACE were evaluated. Tumorous portal perfusion defect size on CTAP was compared with/without balloon occlusion. Factors influencing discrepancies between selective CTHA with/without balloon occlusion and the degree of iodized oil accumulation were investigated.

Results

Among 27 tumors, tumor enhancement on selective CTHA changed after balloon occlusion in 14 (decreased, 11; increased, 3). In 18 tumors, there was a discrepancy between tumor enhancement on selective CTHA with balloon occlusion and the degree of accumulated iodized oil, which was higher than the tumor enhancement grade in all 18. The tumorous portal perfusion defect on CTAP significantly decreased after balloon occlusion in 18 of 20 tumors (mean decrease from 21.9 to 19.1 mm in diameter; p = 0.0001). No significant factors influenced discrepancies between selective CTHA with/without balloon occlusion. Central area tumor location, poor tumor enhancement on selective CTHA with balloon occlusion, and no decrease in the tumorous portal perfusion defect area on CTAP after balloon occlusion significantly influenced poor iodized oil accumulation in the tumor.

Conclusions

Tumor enhancement on selective CTHA frequently changed after balloon occlusion, which did not correspond to accumulated iodized oil in most cases.

     

CTHA和CTAP在肝癌介入治疗中的应用

目的:研究肝动脉造影CT和经动脉门脉造影CT在肝癌介入治疗中的应用价值和意义。方法:10例原发性肝癌介入治疗前行肝动脉造影CT(CTHA)和经动脉门脉造影CT(CTAP)检查;术中行数字减影肝动脉造影(DSA)。结果:CTHA、CTAP联合检查与常规CT、DSA比较,分别多发现新癌灶11个(26/37)和12个(25/37)。准确判断非复发癌灶2个和1个坏死灶。结论:CTHA、CTAP是肝癌介入治疗前准确判断肿瘤数量和存活度最敏感和准确的方法,对于介入治疗方案的实施、疗效评价有很重要的作用。     

Progression to hypervascular hepatocellular carcinoma: correlation with intranodular blood supply evaluated with CT during intraarterial injection of contrast material

PURPOSE: To analyze the correlation between intranodular blood supply of borderline lesions (ie, dysplastic nodules or hypovascular well-differentiated hepatocellular carcinoma [HCC] nodules) and their progression to hypervascular classic HCC in cirrhotic livers. MATERIALS AND METHODS: One hundred seventy-six borderline lesions seen at computed tomography (CT) during arterial portography (CTAP) and CT during hepatic arteriography (CTHA) were evaluated in 49 patients with cirrhosis who underwent repeated CTAP and/or CTHA but no therapy. On the basis of CTAP findings, nodules were categorized as group A (showing almost the same portal venous supply as the surrounding liver), group B (showing decreased portal venous supply) or group C (showing partially absent portal venous supply); on the basis of CTHA findings, nodules were categorized as group I (showing almost the same arterial supply as the liver), group II (showing decreased arterial supply), or group III (showing partially increased arterial supply). RESULTS: Progression to classic HCC was observed in 29.4% of group A nodules, 53.9% of group B nodules, and 87.9% of group C nodules within 1,000 days; in 58.6% of group I nodules, 12.9% of group II nodules, and 92.2% of group III nodules within 730 days; and in 0% of nodules in group A and I, 28% of nodules in group B and/or II, and 88.7% of nodules in group C and/or III within 730 days. CONCLUSION: Evaluation of intranodular blood supply was valuable in predicting the prognosis in borderline lesions, except when only arterial blood supply was evaluated.     

Ferumoxide-enhanced MR imaging of hepatocellular carcinoma: correlation with histologic tumor grade and tumor vascularity

PURPOSE: To evaluate ferumoxide-enhanced MR imaging findings of hepatocellular carcinomas (HCCs) in correlation with the histologic tumor grades and the tumor vascularity evaluated by CT hepatic arteriography (CTHA) and CT during arterial portography (CTAP) combined. MATERIALS AND METHODS: By searching the radiologic, surgical, and pathologic reports of our institution between January 1999 and February 2001, we identified 43 patients with 51 pathologically confirmed HCCs who underwent ferumoxide-enhanced MR imaging and combination CTHA and CTAP within two weeks. The HCCs consisted of 17 well-differentiated, 28 moderately differentiated, and six poorly differentiated tumors. The MR and CT were retrospectively reviewed by two radiologists in consensus for signal intensity on MR images and vascularity on CT. The Spearman's rank correlation coefficient was calculated to correlate the frequency of tumors with ferumoxide uptake with the histologic tumor grades and the tumor vascularity on CTHA and CTAP. RESULTS: A total of 45 tumors (88%) did not take up ferumoxide, and thus showed distinct, homogeneous hyperintensity. Six tumors (12%) ranging 5-16 mm in size (mean, 11 mm) took up ferumoxide, and thus showed isointensity, mixed intensity, or hypointensity, including five of 17 (29%) well-differentiated tumors and one of 28 (4%) moderately differentiated tumors. Five of the six tumors (83%) showed hyper- or hypovascularity on CTHA or hypovascularity on CTAP. The frequency of tumors with ferumoxide uptake showed weak correlation with tumor grades (coefficient = 0.26, P < 0.01) and vascularity on CTHA (-0.35, P < 0.05) and CTAP (0.39, P < 0.01). CONCLUSION: Although a small number of well-differentiated HCC take up ferumoxide and show iso-, mixed, or hypointensity, most such tumors show increased hepatic arterial or decreased portal venous perfusion. The present results suggest the limitation of reticuloendothelial contrast imaging, particularly in the diagnosis of small, well-differentiated HCC.