Takeshi Kamura

Detection and characterization of focal liver lesions: a Japanese phase III, multicenter comparison between gadoxetic acid disodium-enhanced magnetic resonance imaging and contrast-enhanced computed tomography predominantly in patients with hepatocellular carcinoma and chronic liver disease.

Objectives:To prospectively evaluate the safety and efficacy of combined unenhanced and gadoxetic acid disodium (Gd-EOB-DTPA)-enhanced magnetic resonance (MR) imaging compared with unenhanced MR imaging and triphasic contrast-enhanced spiral computed tomography (CT) for the detection and characterization of focal liver lesions. Materials and Methods:The study was reviewed and approved by the institutional review board at each of the 15 centers involved in the study, and informed written consent was given by all patients. In total, 178 patients with suspected focal hepatic lesions (based, in most patients, on CT, tumor marker and ultrasound examinations) underwent combined MR imaging with a single, rapid injection of Gd-EOB-DTPA 0.025 mmol/kg, including T1-weighted dynamic and delayed MR images 20 to 40 minutes postinjection. Triphasic contrast-enhanced CT, the comparator examination, was performed within 4 weeks of MR imaging. Standard of references (SOR) were resection histopathology and intraoperative ultrasonography, or combined CT during arterial portography and CT hepatic arteriography; in cases where, although the major lesions were treated, some lesion(s) were not treated, follow-up superparamagnetic iron oxide-enhanced MR imaging was additionally performed. All images were assessed for differences in lesion detection and characterization (specific lesion type) by on-site readers and 3, blinded (off-site) reviewers. All adverse events (AEs) occurring within 72 hours after Gd-EOB-DTPA administration were reported. Results:Overall, 9.6% of patients who received Gd-EOB-DTPA reported 21 drug-related AEs. A total of 151 patients were included in the efficacy analysis. Combined MR imaging showed statistically higher sensitivity in lesion detection (67.5%–79.5%) than unenhanced MR imaging (46.5%–59.1%; P < 0.05 for all). Combined MR imaging also showed higher sensitivity in lesion detection than CT (61.1%–73.0%), with the results being statistically significant (P < 0.05) for on-site readers and 2 of 3 blinded readers. Higher sensitivity in lesion detection with combined MR imaging compared with CT was also clearly demonstrated in the following subgroups: lesions with a diameter ≤20 mm (lesions ≤10 mm: 38.0%–55.4% vs. 26.1%–47.3%, respectively; lesions 10–20 mm: 71.1%–87.3% vs. 65.7%–78.4%, respectively); in cirrhotic patients (64.5%–75.4% vs. 54.5%–70.3%, respectively); and in patients with hepatocellular carcinoma (66.6%–78.6% vs. 59.1%–71.6%, respectively). Combined MR imaging demonstrated a higher proportion of correctly characterized lesions (50.5%–72.1%) than unenhanced MR imaging (30.2%–50.0%; P < 0.05 for all), whereas there were no significant differences compared with CT (49.0%–68.1%), except for one blinded reader (P < 0.05). Conclusion:In this study, hepatocyte-specific Gd-EOB-DTPA was shown to be safe and to improve the detection and characterization of focal hepatic lesions compared with unenhanced MR imaging. When compared with spiral CT, Gd-EOB-DTPA enhanced MRI seems to be beneficial especially for the detection for smaller lesions or hepatocellular carcinoma underlying cirrhotic liver.

Clinical and imaging features of distended scapulothoracic bursitis: spontaneously regressed pseudotumoral lesion.

Objective: To describe clinical and imaging findings of distended scapulothoracic bursitis without scapular snapping, which is often confused with a soft tissue tumor. Methods: Nine patients (6 male, 3 female; age range: 50–73 years; mean age = 67 years) with distended scapulothoracic bursitis diagnosed by clinical and magnetic resonance (MR) imaging findings were studied. The results of a histologic examination were available in 1 case. Results: All patients presented with painless palpable masses below the scapula, and the initial diagnoses were soft tissue tumors. On MR images, the lesions were 5.5 to 12 cm in maximum diameter (mean = 7.7 cm) and well-demarcated cystic masses situated in the subscapular region between the serratus anterior and the chest wall. There was no solid portion on the cyst walls. The findings of hemorrhage within the bursae were present in all cases. Every mass regressed in size spontaneously after a few to several weeks, and no lesions revealed any malignant findings of sarcomas. Conclusions: Distended scapulothoracic bursae without scapular snapping resemble soft tissue tumors. They have some specific MR findings; therefore, precise recognition of these findings is important to avoid misdiagnoses and unnecessary treatments.

Hepatic perfusion abnormalities during treatment with hepatic arterial infusion chemotherapy: Value of CT arteriography using an implantable port system

PURPOSE The purpose of this study was to evaluate CT arteriography (CTA) using an implantable port system in the detection of perfusion abnormalities occurring during hepatic arterial infusion chemotherapy (HAIC). METHOD In 51 patients with unresectable primary and metastatic liver tumors, who had implanted port systems for HAIC, CTA examinations through the infusion pump were performed. When perfusion abnormalities were found, selective angiography and/or digital subtraction angiography using the implantable port system were performed to determine the etiology. RESULTS Forty-nine perfusion abnormalities were detected in 32 patients. Intrahepatic hypoperfusion was found in 24 cases. Of 11 patients in whom correction of the hypoperfusion was attempted, it was successful in 10. Of 13 patients in whom correction was not attempted, 6 patients showed progressive disease in nonperfused areas. Intrahepatic hyperperfusion was found in 14 cases, which showed no subsequent complication. Extrahepatic perfusion was found in 11 cases. CONCLUSION We consider CTA to be useful in detecting perfusion abnormalities that may compromise HAIC.

Imaging of benign hypervascular hepatocellular nodules in alcoholic liver cirrhosis: differentiation from hypervascular hepatocellular carcinoma.

Objectives: To retrospectively describe imaging analyses of benign hypervascular hyperplastic liver nodules (HHN) that resulted from alcoholic liver cirrhosis and to examine the possibility of imaging differentiation between these nodules and hypervascular hepatocellular carcinoma (HCC). Methods: Ten histopathologically confirmed HHN arise in alcoholic liver cirrhosis, and 9 HCC were examined. Magnetic resonance imaging (MRI) (10 HHN and 9 HCC), superparamagnetic iron oxide-enhanced T2-weighted MRI (6 HHN and 4 HCC), and dual-phase computed tomography hepatic arteriography (5 HHN and 6 HCC) were performed, respectively. Results: On T1-weighted magnetic resonance images, 7 HHNs showed hyperintensity and 3 showed iso- to hypointensity, and allHCCs showed hypointensity compared with surrounding liver. On T2-weighted magnetic resonance images, 2 HHNs showed hyperintensity and 8 showed iso- to hypointensity. In contrast, 1 HCC showed hypointensity and 8 showed hyperintensity. On superparamagnetic iron oxide-enhanced T2 MRI, all HHNs showed iso- to hypointensity, and all HCCs showed hyperintensity. All HHN and HCCs subjected to dual-phase computed tomography hepatic arteriography showed enhancement on early-phase images and coronalike enhancement on late-phase images. Conclusions: Imaging findings of highly-well differentiated HCCs possibly overlap with HHN. So, for correct diagnosis of HHN, at first, we should suspect HHN based on clinical findings and MRI findings, and then perform core needle biopsy to verify the radiological diagnosis.

Small hypervascular hepatocellular carcinoma versus hypervascular pseudolesions: differential diagnosis on MRI

AbstractBackground: We wanted to differentiate small hypervascular hepatocellular carcinoma (HCC) from hypervascular pseudolesion (HPL) on magnetic resonance imaging (MRI). Methods: We reviewed small hypervascular foci (≤2 cm in diameter) on dynamic MRI in patients with chronic liver disease, which were followed-up with serial MRI examinations. Results: Twenty of 34 hypervascular foci were larger at follow-up; 19 of 20 foci had characteristics suggesting HCC; and 14 foci did not grow or disappeared and were judged to be HPLs. There were no differences in the initial sizes and follow-up periods between HCCs and HPLs. On initial MRI, nine of 19 HCCs (47%) and one of 14 HPLs (7%) appeared hyperintense on T2-weighted images. The difference between HCCs and HPLs on T2-weighted images was statistically significant (p= 0.039). Conclusion: HPLs are seen frequently as small hypervascular foci on dynamic MRI in patients with chronic liver disease. Hyperintensity of the foci on T2-weighted images differentiates HCCs from HPLs.

Perinatal magnetic resonance fetal lung volumetry and fetal lung‐to‐liver signal intensity ratio for predicting short outcome in isolated congenital diaphragmatic hernia and cystic adenomatoid malformation of the lung

Aim:  To evaluate the usefulness of magnetic resonance imaging (MRI) in predicting the risk of lethal pulmonary hypoplasia in fetuses.

Magnetic resonance T1 gradient-echo imaging in hepatolithiasis

BackgroundWe examined the role of magnetic resonance T1-weighted gradient-echo (MRT1-GE) imaging in hepatolithiasis.MethodsMRT1-GE, precontrast computed tomography (CT), and magnetic resonance cholangiopancreatography (MRCP) of 10 patients with hepatolithiasis were compared for their diagnostic accuracies in the detection and localization of intrahepatic calculi. The diagnosis of hepatolithiasis was confirmed by surgery. For localization of the stone, we divided the bile ducts into six areas: right and left hepatic ducts and bile ducts of the lateral, medial, right anterior, and right posterior segments of the liver. Chemical analysis of the stones was performed in eight patients.ResultsThe total number of segments proved by surgery to contain stones was 18. Although not significantly different, the sensitivity of MRT1-GE was 77.8% (14 of 18 segments), higher than that of MRCP (66.7%, 12 of 18 segments) and that of CT (50%, nine of 18 segments). The sensitivity of magnetic resonance imaging (MRCP + MRT1) was significantly higher than that of CT (p < 0.01). Multiple logistic regression analysis showed that the result of surgery was significantly affected only by the result of magnetic resonance imaging. On MRT1-GE, all the depicted stones appeared as high-intensity signal areas within the low-intensity bile duct irrespective of their chemical composition.ConclusionMRT1-GE imaging provides complementary information concerning hepatolithiasis.

Quantitative MRI of hepatocellular carcinoma in cirrhotic and noncirrhotic livers.

Magnetic resonance imaging (MRI) of hepatocellular carcinoma (HCC) in cirrhotic and noncirrhotic livers was reviewed in 26 Japanese patients. Thirteen of the 15 HCC from noncirrhotic livers were iso- to low intense to surrounding parenchyma on T1-weighted spin-echo (SE) images. In contrast, seven of the 11 HCC in cirrhotic livers were high intense (p < 0.05). Signal intensity ratio and contrast-to-noise ratios of HCC in cirrhotic livers on T1-weighted images were higher (p < 0.05 and p < 0.01, respectively) than those of HCC in noncirrhotic livers.

SPECT imaging in a case of primary respiratory tract amyloidosis.

SPECT findings in a very rare case of primary amyloidosis localized in the laryngotracheobronchial area are reported. SPECT using Tc-99m PYP revealed widespread uptake in the larynx and the entire tracheobronchial tree up to the subsegmental divisions; the areas corresponded to diffuse thickening and calcification of the walls on CT. SPECT using Ga-67 citrate also showed marked uptake in the same area, consistent with the findings shown by SPECT using Tc-99m PYP.

Dynamic computed tomography findings of malignant intraductal papillary mucinous tumor compared with invasive ductal adenocarcinoma

PurposeWe evaluated the effectiveness of dynamic computed tomography (CT) imaging in differentiating malignant intraductal papillary mucinous tumor (IPMT) with a large mural nodule from invasive ductal adenocarcinoma (IDAC).Materials and methodsDynamic CT was done in six IPMT and nine IDAC cases. In the IPMT cases, we made a histological map of the tumor. A region of interest (ROI) was established in the mural nodule of the IPMT, in the IDAC, and in the noncancerous portion of the pancreas. The change of density was analyzed statistically during preenhancement and the early and late phases. These results were compared between the IPMT and IDAC cases.ResultsHistologically, most of the mural nodule was papillary adenocarcinoma. In the IPMT cases, the postenhancement density of the mural nodule was significantly higher during the early phase than during the late phase. In IDAC cases, the postenhancement density was significantly higher in the late phase than in the early phase. In the early phase, tumor–pancreas density was significantly higher in the IPMT than in the IDAC. In the late phase, tumor–pancreas density was significantly higher in the IDAC than in the IPMT.ConclusionDynamic CT is useful for differentiating malignant IPMT with a large mural nodule from IDAC.