Toshio Kaminou

Diagnostic accuracy of diffusion-weighted imaging in differentiating benign from malignant ovarian lesions.

To clarify the diagnostic accuracy of diffusion‐weighted imaging (DWI) in differentiating benign from malignant ovarian lesions.

Significance of apparent diffusion coefficient measurement for the differential diagnosis of multiple system atrophy, progressive supranuclear palsy, and Parkinson's disease: evaluation by 3.0-T MR imaging

IntroductionThe clinical differentiation of Parkinson’s disease (PD) from multiple system atrophy (MSA) and progressive supranuclear palsy (PSP) may be challenging, especially in their early stages. The aim of this study was to evaluate the utility of apparent diffusion coefficient (ADC) measurement to distinguish among these degenerative disorders.MethodsTwenty-five MSA, 20 PSP, and 17 PD patients and 18 healthy controls were retrospectively studied. Axial diffusion-weighted and T2-weighted images were obtained using a 3-T MR system. Regions of interest (ROIs) were precisely placed in the midbrain, pons, putamen, globus pallidus, caudate nucleus, thalamus, superior cerebellar peduncle, middle cerebellar peduncle, cerebellar white matter, and cerebellar dentate nucleus, and the regional ADC (rADC) value was calculated in each ROI.ResultsIn MSA, rADC values in the pons, middle cerebellar peduncle, cerebellar white matter, and cerebellar dentate nucleus were significantly higher than in PSP, PD, and controls. Furthermore, rADC values in the posterior putamen were significantly higher in MSA than in PSP and controls. In PSP, rADC values were significantly higher in the globus pallidus and midbrain than in MSA, PD, and controls. Furthermore, rADC values in the caudate nucleus and superior cerebellar peduncle were significantly higher in PSP than in MSA and controls. In PD, there were no significant differences in the rADC values compared to in MSA, PSP, and controls in all regions.ConclusionEvaluation of rADC values in characteristic lesions in MSA, PSP, and PD by placing ROIs using 3-T systems can provide useful additional information for differentiating these disorders.

Transcatheter Arterial Embolization of Acute Arterial Bleeding in the Upper and Lower Gastrointestinal Tract with N-Butyl-2-Cyanoacrylate

PURPOSE To assess the clinical utility and safety of transcatheter arterial embolization with N-butyl-2-cyanoacrylate (NBCA) for urgent control of acute arterial bleeding in the upper and lower gastrointestinal tract. MATERIALS AND METHODS Therapeutic NBCA embolization was performed in 37 patients (39 cases; mean age, 67.8 years) with acute upper (n = 16) or lower (n = 23) gastrointestinal tract bleeding after endoscopic management had failed. Transcatheter arterial embolization was performed using 1:1 to 1:5 mixtures of NBCA and iodized oil. The most common etiologies of bleeding were colonic diverticulosis (n = 13), malignancy (n = 11), and benign ulcer (n = 7). Coagulopathy was present in 11 patients, and 23 patients were hemodynamically unstable before NBCA embolization. Histologic examination for bowel ischemia was also performed in five patients who underwent excision of the lesion after NBCA embolization. RESULTS The technical success rate was 100%. Recurrent bleeding occurred in two patients. Complete hemostasis was achieved in all 11 patients with coagulopathy. Ulcers induced by transcatheter arterial embolization were noted in 6 of 20 patients who underwent endoscopic examination; the ulcers were successfully treated with conservative measures. Histologic examination revealed that despite inflammatory reactions in and around the vessels, no intestinal necrosis secondary to NBCA embolization was found. Hepatic abscess occurred in two cases, and ischemia of the lower limb occurred in one case; these complications were managed by percutaneous drainage and bypass surgery. CONCLUSIONS Transcatheter arterial embolization with NBCA is a good treatment option with a high rate of complete hemostasis and a low recurrent bleeding rate, even in patients with coagulopathy.

Correlation between pathology and neuromelanin MR imaging in Parkinson's disease and dementia with Lewy bodies

IntroductionDirect correlation between neuropathological findings and postmortem neuromelanin MR imaging (NmMRI) was performed in the substantia nigra pars compacta (SNc) to clarify the pathological background of the signal changes in normal, Parkinson’s disease (PD), and dementia with Lewy bodies (DLB) cases.MethodsNmMRI of 10 % formalin-fixed autopsied midbrains was performed in three cases (normal control, DLB, and PD) with a 3T imaging system, using a 3D gradient echo T1-weighted sequence with a magnetization transfer contrast pulse. Neuropathological examinations of the midbrains were performed, and the density of neuromelanin-positive neurons (number per square millimeter) was determined. The extent of iron deposition in the midbrain was also evaluated using ferritin immunohistochemistry. Furthermore, we directly correlated the contrast signal ratio in the SNc and the density of neuromelanin-containing neurons.ResultsDiffuse hyperintense areas in the SNc reflected well-preserved neuromelanin-containing neurons in the normal control case, whereas an iso-intense area in the SNc showed severe loss of neuromelanin-containing neurons in the DLB and PD cases. Increased signal intensity in the SNc was apparently not influenced by iron deposition. Furthermore, a significant positive correlation between signal intensity and the density of neuromelanin-containing neurons was seen in the SNc.ConclusionBased on the direct correlation between postportem NmMRI and neuropathological findings, signal intensity in the SNc is closely related to the quantity of neuromelanin-containing neurons but is not influenced by iron deposition.

Usefulness of monochromatic imaging with metal artifact reduction software for computed tomography angiography after intracranial aneurysm coil embolization

Background Recently, a newly developed fast-kV switching dual energy CT scanner with a gemstone detector generates virtual high keV images as monochromatic imaging (MI). Each MI can be reconstructed by metal artifact reduction software (MARS) to reduce metal artifact. Purpose To evaluate the degree of metal artifacts reduction and vessel visualization around the platinum coils using dual energy CT with MARS. Material and Methods Dual energy CT was performed using a Discovery CT750 HD scanner (GE Healthcare, Milwaukee, WI, USA). In a phantom study, we measured the mean standard deviation within regions of interest around a 10-mm-diameter platinum coil mass on MI with and without MARS. Thirteen patients who underwent CTA after endovascular embolization for cerebral aneurysm with platinum coils were included in a clinical study. We visually assessed the arteries around the platinum coil mass on MI with and without MARS. Results Each standard deviation near the coil mass on MI with MARS was significantly lower than that without MARS in a phantom study. On CTA of a clinical study, better visibility of neighboring arteries was obtained in 11 of 13 patients on MI with MARS compared to without MARS due to metal artifact reduction. Conclusion: Dual energy CT with MARS reduces metal artifact of platinum coils, resulting in favorable vessel visualization around the coil mass on CTA after embolization.

Radiofrequency Ablation for the Treatment of Bone Metastases From Hepatocellular Carcinoma

OBJECTIVE The objective of our study was to retrospectively evaluate the clinical utility of bone radiofrequency ablation in patients with bone metastases from hepatocellular carcinoma (HCC). MATERIALS AND METHODS At three institutions, 40 consecutive HCC patients with 54 bone metastases received radiofrequency ablation. The mean maximum diameter of the bone metastases was 4.8 +/- 2.3 (SD) cm (range, 1.0-12.0 cm). The feasibility and safety of the procedure and the pain relief achieved from the procedure were reviewed. Technical success was defined as correct placement of the radiofrequency electrode into the tumor target and completion of the planned ablation protocol. Survival and prognostic factors were evaluated. RESULTS Technical success was 100%. No major complication occurred aside from transient nerve injury in one patient (2.5%, 1/40). Pain relief was achieved in all patients with painful bone metastases except one (96.6%, 28/29). The respective 1-, 2-, and 3-year survival rates were 34.2% (95% CI, 19.2-49.1), 19.9% (95% CI, 7.0-32.8), and 10.0% (95% CI, 0-20.2), with a median survival time of 7.1 months. Complete ablation of bone metastases, a single bone lesion, negative alpha-fetoprotein levels, and the absence of viable intrahepatic lesions were significant factors for a better prognosis. The median survival time was, respectively, 12.5 months in 16 patients with negative alpha-fetoprotein levels, 16.8 months in 12 patients with complete tumor ablation, 16.8 months in 16 patients with a single bone metastasis, and 21.9 months in 17 patients with no viable intrahepatic HCCs. CONCLUSION Bone radiofrequency ablation is a safe, useful, and feasible therapeutic option for relieving pain in patients with HCC bone metastases. Prognostic factors reported herein can facilitate stratification of patients with HCC bone metastases.

Heat Distribution in the Spinal Canal during Radiofrequency Ablation for Vertebral Lesions : Study in Swine

PURPOSE To prospectively evaluate the safety of radiofrequency (RF) ablation for vertebral lesions by monitoring the temperature in swine vertebral models with and without a cortical bone defect. MATERIALS AND METHODS The institutional animal care and use committee approved the animal studies. In vivo and ex vivo studies were performed. In the in vivo study, 20 lumbar vertebrae from six swine were locally heated by using 1- or 2-cm active-tip internally cooled electrodes. In the ex vivo study, 12 fresh pig cadaver lumbar vertebrae were extracted from four swine, and spinal tumor models with or without cortical bone defect were created by stuffing a cavity with muscle tissue and locally heated by using a 1-cm active-tip internally cooled electrode. The temperature was monitored in the spinal canal and around the vertebral body during ablation. Mann-Whitney U test was used to indicate a significant difference between groups by using 1- and 2-cm active tip in the in vivo study and between groups with and without cortical defect in the ex vivo study. RESULTS In the in vivo study in which 1- and 2-cm active-tip needles were used, the temperature in the spinal canal rose to 38.2 degrees C +/- 2.7 (standard deviation) and 45.5 degrees C +/- 6.2, respectively. The latter was significantly higher than the former (P < .001). In the ex vivo study in which tumor models with or without a cortical bone defect were used, the temperature in the spinal canal rose to 48.4 degrees C +/- 6.2 and 31.3 degrees C +/- 3.4, respectively. The former was significantly higher than the latter (P < .001). CONCLUSION For in vivo cases with a 2-cm active tip and ex vivo cases with a vertebral posterior bone defect, the temperature rose to over 45 degrees C, potentially injuring the spinal cord and peripheral nerves.

Apparent diffusion coefficient (ADC) measurement in endometrial carcinoma: Effect of region of interest methods on ADC values

To investigate the influence of different‐shaped regions of interest (ROIs) on tumor apparent diffusion coefficient (ADC) measurements and interobserver variability in endometrial carcinoma.

Percutaneous radiofrequency ablation for pulmonary metastases from hepatocellular carcinoma: Results of a multicenter study in Japan

PURPOSE To retrospectively evaluate technical success, effectiveness, complications, patient survival, and prognostic factors with percutaneous radiofrequency (RF) ablation for pulmonary metastases resulting from hepatocellular carcinoma (HCC). MATERIALS AND METHODS Thirty-two patients from six institutions were included, with a total of 83 pulmonary metastases treated in 65 sessions. RF ablation was always performed percutaneously with computed tomography (CT) guidance. Primary endpoints were technical success and technique effectiveness. Technique effectiveness was evaluated based on sequential follow-up CT images. Secondary study endpoints were complications, patient survival, and determination of prognostic factors. Complications were classified as major or minor. Prognostic factors were determined by analyzing multiple variables with the log-rank test. RESULTS Technical success rate was 100%. Primary technique effectiveness rates were 92% each at 1, 2, and 3 years. Major and minor complications occurred after 16 (25%) and 23 (35%) of the 65 sessions, respectively. The median follow-up period was 20.5 months. Overall survival rates were 87% at 1 year and 57% each at 2 and 3 years (median and mean survival times, 37.7 mo and 43.2 mo, respectively). Significantly better survival rates were obtained in cases of (i) no viable intrahepatic recurrence (P < .001), (ii) Child-Pugh class A disease (P < .001), (iii) absence of liver cirrhosis (P < .001), (iv) absence of hepatitis C virus infection (P = .006), and (v) α-fetoprotein level of 10 ng/mL or lower (P = .007) at the time of RF ablation. CONCLUSIONS RF ablation appears effective, with an acceptable safety profile, in selected patients with pulmonary metastases resulting from HCC.

Diffusion-weighted imaging findings of adnexal torsion: Initial results

Our purpose is to clarify the diffusion-weighted (DW) imaging findings of adnexal torsion. We retrospectively analyzed the DW imaging findings in 11 consecutive patients with surgical confirmation of adnexal torsion. We assessed signal intensity of the adnexal mass and fallopian tube thickening, and the location of abnormal signal intensity within the adnexal mass. On DW imaging, thickening of the fallopian tube was apparent as abnormal signal intensity in 8 of 11 patients. Abnormal signal intensity was inhomogeneous in 7 of 8 patients. Abnormal signal intensity on DW imaging was observed in 10 of 11 adnexal masses, and in the walls of 7 out of 8 adnexal cystic lesions. In adnexal torsion, DW imaging showed abnormal signal intensity in the thickened fallopian tube and in the wall of cystic ovarian lesions. These findings would be feasible to diagnose adnexal torsion.