Jiunn-Ming Lii

Magnetic resonance imaging appearance of well-differentiated hepatocellular carcinoma

Objective: To investigate the magnetic resonance imaging (MRI) features of well-differentiated hepatocellular carcinoma (HCC). Methods: We reviewed the MRI of 32 patients with 33 pathologically confirmed well-differentiated HCC. The MRI protocol included T2-weighted imaging with and without fat saturation, dual-phase T1-weighted imaging, and gadolinium-enhanced dynamic study. The signal intensity of each lesion was categorized as hyperintense, isointense, and hypointense with reference to the surrounding liver parenchyma. Results: Thirty-one (93.9%) of 33 well-differentiated HCC were demonstrated on the MRI. The remaining 2 were isointense in all magnetic resonance sequences and, therefore, could not be identified. Most of them were hyperintense (n = 15 [45.4%]) or isointense (n = 16 [48.5%]) on T1-weighted imaging, and hyperintense (n = 12 [36.4%]) or isointense (n = 17 [51.5%]) on T2-weighted imaging. On the dynamic study, 17 lesions (51.5%) were enhanced. Conclusions: MRI may identify most well-differentiated HCC; however, the imaging appearance is diverse. Biopsy should be performed if magnetic resonance study is inconclusive.

Peritumoral fat-spared area is well correlated with the presence of temporal peritumoral enhancement in hepatic hemangioma in fatty liver.

To assess the relationship between temporal peritumoral enhancement and peritumoral focal fat sparing adjacent to hepatic hemangiomas.

T2-weighted and T1-weighted dynamic superparamagnetic iron oxide (ferucarbotran) enhanced MRI of hepatocellular carcinoma and hyperplastic nodules.

BACKGROUND/PURPOSE Iron oxide contrast medium (ferucarbotran) shortens both T1 and T2 relaxation time. We used the T2- and the T1-weighted dynamic ferucarbotran-enhanced magnetic resonance (MR) imaging to predict the histologic grade of hepatocellular carcinoma (HCC) and to distinguish HCC from hyperplastic nodules. METHODS Forty-three patients with 48 representative hepatic lesions (13 well differentiated HCC, 19 moderately differentiated HCC, 4 poorly differentiated HCC, 12 hyperplastic nodules) were included in the study. T1-weighted image, T2-weighted turbo spin echo, and T2*EPI (echo-planar) images were obtained before and after ferucarbotran injection. The percentage T2 signal intensity loss (T2 PSIL) of the tumors was calculated at 5 minutes and 25 minutes after contrast injection. The enhancement in dynamic T1 images was interpreted by two independent radiologists. RESULTS The T2 PSIL of well differentiated HCC was 39.5 +/- 8.23%, moderately differentiated HCC was 26.4 +/- 13.78%, poorly differentiated HCC was 4.4 +/- 9.42%, and hyperplastic nodules was 44.3 +/- 11.04%. Comparison of T2 PSIL showed significant differences in the three histologically graded HCCs (p < 0.001), but not between the well differentiated HCCs and hyperplastic nodules (p > 0.05). Delayed post-contrast (25 minutes) T2-weighted images were not necessary and shortened the examination time. In the post contrast dynamic T1 study, no significant differences between all the groups was seen. CONCLUSION Ferucarbotran MR images help in differentiating the different histologic grades of HCC but T2 PSIL could not differentiate hyperplastic nodules from well differentiated HCC. Dynamic post contrast T1-weighted images provide no additional information.

Temporal peritumoral enhancement of hepatic cavernous hemangioma: findings at multiphase dynamic magnetic resonance imaging.

ObjectiveTo evaluate the occurrence rate of temporal peritumoral enhancement associated with hepatic cavernous hemangiomas and to correlate that with the speed of intratumoral contrast enhancement and tumor volume. MethodsDynamic magnetic resonance imaging (MRI) of 69 consecutive patients with 136 hemangiomas was reviewed for peritumoral enhancement. Tumor volume was estimated by the largest diameter on T2-weighted images. Speed of intratumoral contrast enhancement was determined by portal phase image and was categorized as rapid (>75% of tumor volume), intermediate (25%–75% of tumor volume), or slow (<25% of tumor volume). ResultsTemporal peritumoral enhancement was found in 37 (26.6%) of 136 hemangiomas. It was more common in hemangiomas with rapid enhancement (30 of 67 cases [44.8%]) than in those with intermediate (3 of 22 cases [13.6%]) and slow (4 of 47 cases [8.5%]) enhancement (P < 0.05). There was no statistically significant relation between lesion size and presence of temporal peritumoral enhancement (P > 0.05). ConclusionsTemporal peritumoral enhancement is not uncommonly seen in hepatic cavernous hemangiomas at dynamic MRI. It is most commonly encountered in rapidly enhancing small lesions. There is no statistically significant relation between temporal peritumoral enhancement and tumor volume, however.

MR cholangiopancreatography: prospective comparison of 3-dimensional turbo spin echo and single-shot turbo spin echo with ERCP.

BACKGROUND AND PURPOSE Magnetic resonance cholangiopancreatography (MRCP) is a non-invasive technique for examination of the biliopancreatic tract. Respiratory-triggered 3-dimensional turbo spin echo (3DTSE RT) and breath-hold thick slab single-shot turbo spin echo (ssTSE BH) are both useful MRCP techniques. The purpose of this study was to compare these 2 sequences with endoscopic retrograde cholangiopancreatography (ERCP) in patients with biliary tract disease. METHODS Forty four patients with suspected biliary obstruction were recruited to receive MRCP within 3 days before ERCP. MRCP was performed using both 3DTSE RT with maximum intensity projection images and ssTSE BH. ERCP was performed and assessed by 2 endoscopists. RESULTS MRCP was successfully performed in all patients, whereas ERCP failed in 6 patients (13.6%). MRCP was effective in detecting the presence of choledocholithiasis in 13 of 14 patients, ERCP in 12 of 12, and 2 failed ERCP. MRCP was effective in detecting benign biliary obstruction in 18 of 19 patients, and ERCP in 15 of 15, but 4 patients failed ERCP and choledocholithiasis was misdiagnosed by MRCP in 1 patient. Both MRCP and ERCP correctly diagnosed malignant bile duct obstruction in 10 of 11 patients, and both misdiagnosed that condition as benign obstruction in 1 patient. There was no significant difference between MRCP and successful ERCP in detecting lesions. MRCP was significantly better than ERCP when both successful and failed ERCP were encountered (p = 0.0498). Both 3DTSE RT and ssTSE BH produced the same results in depicting the biliary ducts and lesions in 37 patients (84.1%). Four patients (9.1%) showed better images on 3DTSE RT, whereas 3 patients (6.8%) showed better images on ssTSE BH. CONCLUSIONS 3DTSE RT and the ssTSE BH were complementary to each other in MRCP studies. Using these 2 techniques, MRCP has a high successful rate and diagnostic accuracy when compared with ERCP in detecting bile duct disease.

Delineation of the Watershed between Right and Left Hepatic Arterial Territories with Carbon Dioxide–enhanced Ultrasonography

PURPOSE To delineate the watersheds between hepatic arterial territories and their variations with the use of CO(2)-enhanced ultrasonography (US) and to compare the results with segmental anatomy as described by Couinaud. MATERIALS AND METHODS From March 2004 to January 2005, this study recruited 31 patients (18 men and 13 women; mean age, 63 years; range, 47-77 y) with hepatocellular carcinoma (HCC) who were scheduled to receive transarterial chemoembolization. After serial angiography, CO(2)-enhanced US was performed with catheters superselectively inserted into the hepatic arteries. The territorial divisions between hepatic arteries were compared with the anatomic courses of the middle and left hepatic veins. Data from 17 patients were used to assess the vascular territories of the right and left lobe and data from the remaining 14 patients were used to assess those of the left medial and left lateral segments. RESULTS Mapped arterial territories exactly matched Couinaud segments in 17 of 31 patients (54.8%). They did not coincide with Couinaud segments in 45.2% of patients with HCC. Crossover enhancement was noted over the right and left lobes and over the left medial and lateral segments in seven patients each. Two tumors located exactly in watershed areas showed CO(2) enhancement across the hepatic vein. CONCLUSIONS CO(2)-enhanced US is useful to delineate arterial territories of hepatic segments and show crossover arterial supply compared with Couinaud segments. Awareness of crossover arterial supply is important for chemoembolization, segmental chemoembolization, hepatic arterial infusion, sonography, and surgery.

Characterization of hyperintense nodules on T1-weighted liver magnetic resonance imaging: Comparison of Ferucarbotran-enhanced MRI with accumulation-phase FS-T1WI and gadolinium-enhanced MRI

Background: T1‐weighted (T1W) hyperintense nodules against a background of cirrhosis are diagnostically challenging in daily practice. All regenerative nodules, dysplastic nodules and hepatocellular carcinoma (HCC) might present hyperintense on T1W imaging (T1WI), so T1W hyperintense nodules cannot be definitively characterized as dysplastic nodules or HCC before biopsy, resection or transplantation. The purpose of our study was to evaluate Ferucarbotran‐enhanced Magnetic Resonance Imaging (MRI) with accumulation‐phase fat suppression T1‐weighted imaging (FS‐T1WI) in comparison with gadolinium‐enhanced MRI for characterization of hyperintense nodules on unenhanced T1WI within cirrhotic liver. Methods: Two separate groups of patients with histologically‐proven T1W hyperintense nodule on MRI were retrospectively identified. The Ferucarbotran group consisted of 17 T1W hyperintense nodules in 12 patients. The gadolinium group consisted of 22 T1W hyperintense nodules in 21 patients. All of the patients had liver cirrhosis. Finally, 11 HCC nodules, and six benign nodules were included in the Ferucarbotran group; 15 HCC nodules and seven benign nodules were included in the gadolinium group. Results: With the conventional criteria, in the gadolinium‐enhanced group, the sensitivity, specificity, and accuracy were 53%, 100%, and 73%, respectively. Using the conventional criteria in the Ferucarbotran group, the sensitivity, specificity, and accuracy were 73%, 100%, 82%, respectively. Using the conventional criteria plus hyperintense on the accumulation‐phase FS‐T1WI in the Ferucarbotran group for characterization of the T1W hyperintense nodules, the sensitivity, specificity, and accuracy were 100%, 83%, 94%, respectively. The sensitivity of Ferucarbotran‐enhanced MR with accumulation‐phase FS‐T1WI was better than that of gadolinium‐enhanced MRI (p = 0.01). Conclusion: Ferucarbotran‐enhanced MRI with accumulation‐phase FS‐T1WI is superior to gadolinium‐enhanced MRI in characterization of T1W hyperintense nodules within cirrhotic liver. T1W hyperintense nodule within cirrhotic liver depicting hyperintense on Ferucarbotran‐enhanced accumulation‐phase FS‐T1WI should be investigated aggressively.

The diameter of the common bile duct in an asymptomatic Taiwanese population: Measurement by magnetic resonance cholangiopancreatography

Background: Magnetic resonance cholangiopancreatography (MRCP) is a popular modality for evaluation of the biliary tract, yet there is no data on the normal common bile duct (CBD) size of the average Taiwanese adult. This study attempts to establish a reference range for CBD diameter for the Taiwanese population. Methods: Over a 2‐year period, all adults who underwent abdominal magnetic resonance imaging for health screening were recruited into the study. Patients with a prior history of hepatobiliary surgery and other significant morbidity were not included. Patients who were found to have abnormal liver function test results or abnormal imaging findings were also excluded from the study. After the patients fasted for a minimum of 8 hours, MR imaging was performed with a 1.5 T MR imager using a phased‐array coil. Breath‐hold thick slab single‐shot turbo spin echo (ssTSE BH) projections were obtained, and these were used for CBD and portal vein diameter (PVD) measurement by workstation software. Initial recruitment included 265 patients, of which 66 were excluded due to abnormal liver function tests, seven more were excluded due to excess imaging artifacts or incomplete CBD visualization, and five were excluded due to other abnormal blood tests. This yielded a final study group of 187 patients between the ages of 21 and 78 years, which comprised 69 women and 118 men. Results: The mean CBD diameter is 4.6 mm, with a range from 1.76 to 10.49 mm. CBD diameters are significantly different in patients both younger and older than 65 years of age (p < 0.05), and are not significantly related to gender, serum glucose level, cholesterol level, hepatitis status and PVD. Conclusion: Our study showed that the average CBD diameter for an asymptomatic Taiwanese adult is 4.6 mm, with an upper limit of 10.49 mm. CBD diameter is only significantly correlated with age. This is a useful reference in todays clinical setting where MRCP are commonly performed for evaluation of suspected biliary tract disease.

Use of Two-dimensional Multiple-slice Magnetic Resonance Hydrography for Diagnosis of Hepatic Hemangiomas and Cysts

BACKGROUND/PURPOSE Although hepatic hemangiomas and cysts display very high signal intensities on conventional T2 images, their appearances are quite distinct using magnetic resonance hydrography (MRH). We examined the feasibility of using MRH in distinguishing hepatic cysts from hemangiomas. METHODS We recruited 97 patients with hepatic hemangiomas and 65 with hepatic cysts. All patients underwent magnetic resonance imaging (including two-dimensional multiple slice MRH, TR/TE: 8000/800) and the results were reviewed independently by two radiologists. The signal intensities of the lesions were measured. For each lesion, the variation in signal to noise ratio between MRH and the fat-saturated T2-weighted images was calculated, and the results were validated using a receiver operating characteristic curve. RESULTS There was a significant difference between the signal to noise ratio of hepatic hemangiomas and cysts using MRH (p < 0.001). This difference could be identified by visual inspection. The receiver operating characteristic curve revealed that the ideal cut-off value for the signal intensity reduction ratio between hepatic cysts and hemangiomas was -0.1. Using this ratio, the derived sensitivity was 95.4%, specificity 99.0%, and accuracy 99.7%. CONCLUSION Hepatic hemangiomas and cysts have significantly different signal intensities on non-contrast two-dimensional multiple-slice MRH. This approach uses a non-invasive, reliable, and accurate imaging technique to differentiate the two diagnoses.