Hsing-Yang Tu

Blood perfusion of vertebral lesions evaluated with gadolinium-enhanced dynamic MRI: In comparison with compression fracture and metastasis

To investigate blood perfusion of vertebral lesions using dynamic Gd‐DTPA‐enhanced MRI.

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.

The value of ultrasound measurement of gallbladder wall thickness in predicting laparoscopic operability prior to cholecystectomy

We prospectively analysed 51 consecutive cases who underwent laparoscopic cholecystectomy from June 1992 to February 1993. There were 35 cases of chronic cholecystitis and 16 cases of acute cholecystitis. All underwent pre-operative ultrasonography, complete blood cell count, liver function test and endoscopic retrograde cholangiopancreatography. Of those 44 had post-operative ultrasound within the first 2 d and again on the seventh day. In 35 cases of chronic cholecystitis, 31 of 32 cases with a pre-operative gallbladder (GB) wall thickness of less than 6 mm were successfully resected laparoscopically. All three cases with a GB wall thicker than 6 mm were converted to open cholecystectomy. In acute cholecystitis, the wall thickness of the laparoscopic cholecystectomy group ranged from 2 to 9 mm (average 4 mm) and the wall thickness of the conversion group was 4-7 mm (average 6 mm). Post-operative fluid accumulation was noted in 28 (63.6%) cases. There was no correlation between post-operative pyrexia, duration of post-operative pain, clinical complications and the presence of fluid accumulation in the GB fossa. However, of four cases with increasing fluid on the seventh day, three developed complications. We conclude that ultrasonography is valuable in chronic cholecystitis for selecting cases for laparoscopic cholecystectomy.

Intra-arterial carbon dioxide-enhanced ultrasonogram of hepatocellular carcinoma treated by transcatheter arterial embolization and percutaneous ethanol injection therapy

The purpose of this study was to investigate the value of carbon dioxide‐enhanced ultrasonography (CO2‐US) in the evaluation of viable hepatocellular carcinomas (HCC) which were treated by transcatheter arterial embolization (TAE), percutaneous ethanol injection (PEI), or a combination treatment (TAE and PEI). Forty‐one patients with 66 HCC were included in the study. They underwent CO2‐US and angiography were performed in all tumours after they were treated by TAE, PEI or a combination treatment. Forty‐six tumours were positively enhanced by CO2‐US and 40 of them were positive by angiography. These 46 tumours were proved to be viable tumours either by biopsy or by follow‐up studies. The positive predictive value was 100% for CO2‐US and 87.8% in angiography. Twenty tumours were negative by CO2‐US and these were also negative by angiography. Carbon dioxide‐enhanced ultrasonography is a more reliable method for detecting the viable portion of the treated HCC compared with conventional angiography.

Carbon dioxide-enhanced ultrasonography of liver tumors

CO2 gas‐enhanced ultrasonography was performed in 37 patients (47 studies) for the purpose of detecting small tumors and evaluating differential diagnosis. With conventional ultrasonography, 62 lesions were identified in 25 patients with HCC, 13 tumors were identified in eight patients with hemangioma, and multiple tumors were found in four patients with metastatic adenocarcinoma. CO2‐enhanced ultrasonography detected five additional hemangiomas, 12 additional nodules in HCC, and the same number of metastatic nodules. The patterns of CO2 enhancement were characterized as homogeneous, heterogeneous, rim, internal spotted, negative, and mixed (more than one pattern in one lesion). The rim enhancement pattern was found to be specific for hemangioma. The internal spotted enhancement pattern was found exclusively in HCC. All the lesions that demonstrated negative enhancement were treated HCC. All the metastatic tumors demonstrated the mixed rim and internal spotted enhancement pattern. We suggest that CO2‐enhanced ultrasonography is a useful tool in detecting small liver tumors. It can also help in the differentiation among various hepatic tumors.

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.

Contrast-enhanced ultrasonography of hepatic metastasis of hemangiopericytoma.

Hemangiopericytoma (HPC) was first described by Stout and Murray 1 in 1942. The cellular origin of HPC was thought to come from the pericytes, which are contractile cells surrounding the capillaries and post-capillary venules. 2-4 The tumor was rare and was reported to most frequently affect patients in their fifth and sixth decades of life, with an almost equal distribution in both sexes. 3,4 Because HPC has a high rate of local recurrence and has a potential for metastasis that cannot be predicted by its histopathologic characteristics, the treatment of choice has been wide surgical excision as the initial therapy. 5,6 However, even surgical resection cannot guarantee complete cure of the disease. Metastases were eventually observed in 64.5% of patients considered to have malignant or potentially malignant tumors. Most of the metastases occurred within 3 years after initial treatment but have been reported to occur after as long as 16 years. 4 The lung, skeleton, and liver were the most common metastatic sites. 3,4,6,7 Contrast-enhanced ultrasonography (CEUS) has allowed excellent depiction of lesional vascularity within focal liver masses. Here we report CEUS of metastatic HPC of the liver. To our knowledge, this is the second case of HPC studied with CEUS reported in the literature.

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.