Shinji Hirohashi

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.

Displacement of the facial nerve course by vestibular schwannoma: Preoperative visualization using diffusion tensor tractography

To preoperatively visualize the course of the facial nerve, which is displaced by vestibular schwannoma, using diffusion tensor (DT) tractography, and to evaluate the agreement with surgical findings.

Comparison of gadobenate dimeglumine with gadopentetate dimeglumine for magnetic resonance imaging of liver tumors

Kuwatsuru R, Kadoya M, Ohtomo K, et al. Comparison of gadobenate dimeglumine with gadopentetate dimeglumine for magnetic resonance imaging of liver tumors. Invest Radiol 2001;36:632–641. rationale and objectives. To compare gadobenate dimeglumine (Gd-BOPTA) with gadopentetate dimeglumine (Gd-DTPA) for magnetic resonance imaging of the liver. methods.The contrast agent Gd-BOPTA or Gd-DTPA was administered at a dose of 0.1 mmol/kg to 257 patients suspected of having malignant liver tumors. Dynamic phase images, spin-echo images obtained within 10 minutes of injection, and delayed images obtained 40 to 120 minutes after injection were acquired. All postcontrast images were compared with unenhanced T1-weighted and T2-weighted images obtained immediately before injection. A full safety assessment was performed. results.The contrast efficacy for dynamic phase imaging was moderately or markedly improved in 90.9% (110/121) and 87.9% (109/124) of patients for Gd-BOPTA and Gd-DTPA, respectively. At 40 to 120 minutes after injection, the cor- responding improvements were 21.7% (26/120) and 11.6% (14/121) for spin-echo sequences and 44.5% (53/119) and 19.0% (23/121) for breath-hold gradient-echo sequences, respectively. The differences at 40 to 120 minutes after injection were statistically significant (P < 0.02). Increased information at 40 to 120 minutes after injection compared with information acquired within 10 minutes of injection was available for 24.0% (29/121) of patients with Gd-BOPTA and for 14.5% (18/124) of patients with Gd-DTPA (P < 0.03). Adverse events were seen in 4.7% (6/128) and 1.6% (2/127) of patients receiving Gd-BOPTA and Gd-DTPA, respectively. The difference was not statistically significant. conclusions.The efficacy of Gd-BOPTA is equivalent to that of Gd-DTPA for liver imaging during the dynamic phase and superior during the delayed (40–120 minutes) phase of contrast enhancement. Both agents are safe for use in magnetic resonance imaging of the liver.

Segmental transarterial chemoembolization with lipiodol mixed with anticancer drugs for nonresectable hepatocellular carcinoma: follow-up CT and therapeutic results

We developed segmental Lp-TAE, which is transcatheter hepatic sub-subsegmental, subsegmental, or segmental chemoembolization using Lipiodol introduced into the tumor-bearing hepatic sub-subsegment, subsegment, or segment as the target area. A total of 98 patients with nonresectable hepatocellular carcinoma (HCC) undergoing segmental Lp-TAE (Seg-Lp-TAE) were studied, and the relationship between the CT pattern observed after Seg-Lp-TAE (Seg-Lp-CT) and the therapeutic results obtained in those patients was evaluated. Seg-Lp-CT was classified into four types (type I, homogeneous; type II, defective; type III, inhomogeneous; and type IV, only slight accumulation, if any) according to the Lipiodol accumulation pattern observed after Seg-Lp-TAE. The cumulative nonrecurrence rates of type I were higher than those of types II–IV. The cumulative survival rates of type Ia, in which Lp accumulation is also seen around the main tumor, were the highest (93.8% at 1 year, 85.9% at 2 years, 85.9% at 3 years, and 57.3% at 4 years). The cumulative survival rates achieved with Seg-Lp-TAE were 89.2% at 1 year, 69.4% at 2 years, 58.9% at 3 years, 44.0% at 4 years, and 30.2% at 5 years, which were higher than those achieved with conventional Lp-TAE. Seg-Lp-TAE is very useful in the treatment of HCC limited to one sub-subsegment, subsegment, or segment, and it is important to choose subsubsegmental, subsegmental, subsegmental, or segmental Lp-TAE on the basis of the size and site of the tumor as well as the type and the number of feeding arteries.

A new evaluation of pancreatic function after pancreatoduodenectomy using secretin magnetic resonance cholangiopancreatography

BACKGROUND The remnant pancreatic function after pancreatoduodenectomy influences greatly postoperative quality of life. However, it has been difficult to evaluate the exocrine remnant pancreatic function postoperatively. The aim of this study was to assess the usefulness of secretin-stimulated magnetic resonance cholangiopancreatography (secretin MRCP) in evaluating the remnant pancreatic function and ascertaining the anastomotic patency after pancreatoduodenectomy. METHODS Thirty-four patients who underwent pancreatoduodenectomy were evaluated with secretin MRCP. The results of MRCP were determined by the amount of exocrine pancreatic secretion, and were graded as follows: grade I (poor secretion), grade II (moderate secretion), and grade III (good secretion). RESULTS Secretin MRCP could visualize the pancreatic secretion dynamically. MRCP grades were grade I in 11 patients, grade II in 12, and grade III in 11. There was a significant correlation between MRCP grade and glucose tolerance. We confirmed visually the patency of the anastomotic site in 24 patients (71%). MRCP grades correlated significantly with clinical symptoms. CONCLUSION Our results demonstrated secretin MRCP was feasible for evaluating the remnant pancreatic function after pancreatoduodenectomy.

Large scale clinical evaluation of bowel contrast agent containing ferric ammonium citrate in MRI

Clear identification of bowel has been thought to be essential in diagnosis by abdominal MRI. We have completed the clinical phase III trial of a new oral contrast agent (FerriSeltz) which is a ferric ammonium citrate based bowel contrast agent. FerriSeltz is a powder that is dissolved in 300 ml water to create a grape-flavored effervescent drink. We have evaluated the usefulness of FerriSeltz, and compared groups receiving 600 mg and 1200 mg of ferric ammonium citrate, the use and nonuse of parasympathetic blockers, and patients with and without fasting in 174 patients who underwent abdominal MRI using this agent. FerriSeltz was found to brighten the stomach and duodenum, contribute to the improvement in diagnostic efficacy, be safe as a bowel contrast agent in abdominal MRI, and be associated with an extremely low incidence of side effects (only mild diarrhea in one of 169 patients). No significant differences were found in the contribution to the improvement in diagnostic efficacy between the two dosage groups, the use and nonuse of parasympathetic blockers, or patients with and without fasting. We concluded that ferric ammonium citrate based compound (FerriSeltz) is a promising bowel contrast agent in abdominal MRI.

Evaluation of gadobenate dimeglumine in hepatocellular carcinoma: results from phase II and phase III clinical trials in Japan.

To evaluate the clinical efficacy of gadobenate dimeglumine (Gd‐BOPTA)‐enhanced magnetic resonance imaging for hepatocellular carcinoma (HCC), we reviewed the results of clinical phase II and III trials in Japan. Gd‐BOPTA was administered at a dose of 0.1 mmol/kg to 139 patients who were suspected to have HCC. Dynamic phase images [breath‐hold T1‐weighted gradient echo (GRE)], spin‐echo (SE) images obtained within 10 minutes of injection, and delayed breath‐hold GRE images obtained 40–120 minutes after injection were evaluated. All post‐contrast images were compared with T1‐ and T2‐weighted pre‐contrast images.

Three-dimensional power Doppler sonography of tumor vascularity.

The purpose of this study was to assess the value of routine clinical examination using three‐dimensional power Doppler sonography of intratumoral blood flow. Twenty‐two hepatocellular carcinomas, seven cases of hepatic metastasis, four hepatic hemangiomas, six renal cell carcinomas, two cases of hepatic focal nodular hyperplasia, and one case of splenic metastasis were included in the study. Three‐dimensional images were reconstructed by maximum intensity projection method using cine‐loop data on a built‐in computer in a LOGIQ 500 and a LOGIQ 700 from GE Yokogawa Medical Systems. The three‐dimensional images obtained were viewed multidirectionally on a monitor screen. Three‐dimensional representations of intratumoral blood flow became available for all tumors approximately 5 s to 30 s after scanning. In every case, the entire vasculature of the tumor was appreciated more easily from three‐dimensional images than from cross‐sectional two‐dimensional images. These three‐dimensional images of intratumoral blood flows corresponded to the tumor vessels that could be visualized by angiography at the early arterial phase. Differential diagnosis of hepatic tumors based on distinct difference in their intratumoral vascular structures was performed. Our results suggest that three‐dimensional power Doppler sonography can be used for routine clinical examination of tumor vascularity and may provide improved diagnostic information.

Annular pancreas diagnosed by single-shot MR cholangiopancreatography

Magnetic resonance cholangiopancreatography (MRCP) has become widely used due to the rapid advances made as a non-invasive diagnostic method for the pancreatobiliary ducts. We report a case with annular pancreas in an adult in whom the pancreatic duct in the annular portion could be clearly visualized by magnetic resonance cholangiopancreatography, which was very useful for the definite diagnosis as annular pancreas.

Borderline Brenner tumor of the ovary: MRI findings.

Ovarian Brenner tumor is an uncommon epithelial tumor that accounts for 1.5% to 2.5% of all ovarian neoplasms. These tumors are usually benign. Whereas the magnetic resonance imaging features of benign Brenner tumors have been described, reports of malignant findings are limited. We report a case of borderline malignant Brenner tumor that imaged as a cystic lesion with papillary projections and solid elements.