Sho Kudo

Evaluation of acoustic radiation force impulse elastography for fibrosis staging of chronic liver disease: a pilot study

Background: Acoustic radiation force impulse (ARFI) is a new technology integrated into conventional B‐mode ultrasonography. ARFI is used to evaluate tissue stiffness in several organs, but this method has not been applied for liver fibrosis.

Bronchial Artery Embolization for Hemoptysis Due to Benign Diseases: Immediate and Long-Term Results

AbstractPurpose: To clarify the immediate effect and long-term results of bronchial artery embolization (BAE) for hemoptysis due to benign diseases and the factors influencing the outcomes. Methods: One hundred and one patients (aged 34–89 years) received bronchial artery embolization with polyvinyl alcohol particles and gelatin sponge for massive or continuing moderate hemoptysis caused by benign pulmonary diseases and resistant to medical treatment. Results: After BAE, bleeding stopped in 94 patients (94%). The immediate effect was unfavorable in cases where feeder vessels were overlooked or the embolization of the intercostal arteries was insufficient. Long-term cumulative hemoptysis nonrecurrence rates after the initial embolization were 77.7% for 1 year and 62.5% for 5 years. In bronchitis (n = 9) and active tuberculosis (n = 4) groups, an excellent (100%) 5-year cumulative nonrecurrence rate was obtained. The rate was lower in groups with pneumonia/abscess/pyothorax (n = 8) or with pulmonary aspergillosis (n = 9) (53.3%, 1-year cumulative nonrecurrence). There were higher incidences of early recurrence among patients with massive hemorrhage or more marked vascularity and systemic artery–pulmonary artery shunt in angiography: however, these trends were not statistically significant Conclusions: BAE can yield long-term benefit in patients with hemoptysis due to benign diseases. Technical problems in the procedure had an impact on the short-term effect. The degree of hemorrhage or the severity of angiographical findings were not significant factors affecting the outcome. The most significant factor affecting long-term results was whether the inflammation caused by the underlying disease was medically well controlled.

Acquired lesions of the corpus callosum: MR imaging

In this pictorial review, we illustrate acquired diseases or conditions of the corpus callosum that may be found by magnetic resonance (MR) imaging of the brain, including infarction, bleeding, diffuse axonal injury, multiple sclerosis, acute disseminated encephalomyelitis, Marchiafava-Bignami disease, glioblastoma, gliomatosis cerebri, lymphoma, metastasis, germinoma, infections, metabolic diseases, transient splenial lesion, dilated Virchow-Robin spaces, wallerian degeneration after hemispheric damage and focal splenial gliosis. MR imaging is useful for the detection and differential diagnosis of corpus callosal lesions. Due to the anatomical shape and location of the corpus callosum, both coronal and sagittal fluid-attenuated inversion recovery images are most useful for visualizing lesions of this structure.

Spinal cord herniation: report of two cases and review of the literature

Abstract Idiopathic herniation of the spinal cord is an extremely rare disorder which may cause progressive myelopathy. Two cases of this entity reported herein were both examined using MRI and CT myelography. The typical appearance of this disease with or without a dorsal intradural arachnoid cyst is focal ventral displacement of the mid-thoracic spinal cord, mimicking an isolated intradural spinal arachnoid cyst on MRI. CT myelography using thin slice sections is useful in the diagnosis of this disease.

Anterior cerebral artery variations detected by MR angiography.

IntroductionFrom anatomical and angiographic studies, it is well known that there are several variations of the anterior cerebral artery (ACA). However, ACA variations have rarely been studied by magnetic resonance (MR) angiography. The purpose of this study was to investigate not only the type, location, configuration, and incidence of ACA variations, but also coexisting arterial pathology such as aneurysms detected by cranial MR angiography.MethodsWe retrospectively reviewed cranial MR angiography images of 891 patients at our institution. All images were obtained with one of two 1.5-T scanners using the three-dimensional time-of-flight technique. Maximum intensity projection (MIP) images in the horizontal rotation view were displayed stereoscopically. We reviewed these horizontal MIP images, inferosuperior MIP images, and source images, and identified variations of the ACA.ResultsWe found 50 instances (5.6%) of unilateral A1 segment aplasia, 27 (3.0%) of three A2 segments, 18 (2.0%) of an unpaired A2 segment, and 11 (1.2%) fenestrations of the A1 and/or A2 segment. Seven anterior communicating artery (ACoA) aneurysms and one ACA territory embolic infarction were found among the 50 patients with unilateral A1 segment aplasia. One ACoA aneurysm and one pericallosal infarction were found in the 27 patients with three A2 segments. Two distal ACA aneurysms were detected among the 18 patients with an unpaired A2 segment. No associated aneurysm was seen at the fenestrations.ConclusionAlthough the clinical significance of ACA variations is usually minor, an associated aneurysm is found relatively frequently. Thus, recognizing ACA variations during the interpretation of cranial MR angiograms is important.

Manganese accumulation in the brain: MR imaging

Manganese (Mn) accumulation in the brain is detected as symmetrical high signal intensity in the globus pallidi on T1-weighted MR images without an abnormal signal on T2-weighted images. In this review, we present several cases of Mn accumulation in the brain due to acquired or congenital diseases of the abdomen including hepatic cirrhosis with a portosystemic shunt, congenital biliary atresia, primary biliary cirrhosis, congenital intrahepatic portosystemic shunt without liver dysfunction, Rendu-Osler-Weber syndrome with a diffuse intrahepatic portosystemic shunt, and patent ductus venosus. Other causes of Mn accumulation in the brain are Mn overload from total parenteral nutrition and welding-related Mn intoxication.

Sclerosing stromal tumor of the ovary: radiologic findings.

Abstract. Sclerosing stromal tumor is a rare ovarian neoplasm. We describe the radiologic findings of sclerosing stromal tumor in two patients. In both patients, MR and CT images showed a large mass in the left adnexal region. On dynamic contrast-enhanced images, the tumors showed early peripheral enhancement with centripetal progression.

Arterial spin-labeling MR imaging in moyamoya disease compared with SPECT imaging.

OBJECTIVE Arterial spin-labeling (ASL) is a noninvasive magnetic resonance (MR) imaging method used to obtain brain perfusion information on various cerebrovascular diseases. We retrospectively compared the use of ASL-MRI and single-photon emission CT (SPECT) imaging to determine absolute cerebral blood flow (CBF) in moyamoya disease. MATERIALS AND METHODS CBF examinations using ASL-MRI on 3-T MRI and SPECT imagings with iodine-123-N-isopropyl-p-iodoamphetamine at resting (rest-IMP) and after acetazolamide challenge (ACZ-IMP) were performed on 12 patients with moyamoya disease (men, 5; women, 7; age range/average (year), 7-66/35.0). The CBF values determined by ASL-MRI (ASL-value), rest-IMP (rest-IMP-value), and ACZ-IMP (ACZ-IMP-value) of cerebral hemispheres (24 sides) were measured with normalized CBF maps created from data of those 3 perfusion imaging methods. Cerebrovascular reactivity (CVR) was calculated as follows: {(ACZ-IMP-value)-(rest-IMP-value)}/(rest-IMP-value)×100 (%). The ASL-value was compared with the rest-IMP-value, ACZ-IMP-value, and CVR. RESULTS The ASL-value, rest-IMP-value, ACZ-IMP-value, and CVR (average±standard deviation) were 26.6±14.8 (mL/100 g/min), 27.5±6.4 (mL/100 g/min), 37.1±13.2 (mL/100 g/min), and 35.9±44.3 (%), respectively. Significant relationships between the ASL-value versus (vs.) the rest-IMP-value (rs=0.500, p<0.05), the ASL-value vs. the ACZ-IMP-value (rs=0.863, p<0.01), and the ASL-value vs. the CVR (rs=0.699, p<0.01) were observed. CONCLUSION Although the ASL-value was lower than the rest-IMP-value, the significant relationship between the ASL-value and the rest-IMP-value may suggest that perfusion imaging by ASL-MRI could be used to recognize the condition of brain perfusion. In particular, the stronger correlation coefficient between the ASL-value and ACZ-IMP-value might suggest that perfusion imaging by ASL-MRI could show the potentially dangerous zone for ischemia.

CT and MRI findings of human herpesvirus 6-associated encephalopathy: comparison with findings of herpes simplex virus encephalitis.

OBJECTIVE It is important to differentiate human herpesvirus 6 (HHV-6)-associated encephalopathy from herpes simplex encephalitis (HSE). Although these conditions are similar with regard to involvement of the mesial temporal lobe, HSE is sensitive to acyclovir but HHV-6 encephalopathy is not. We compared the imaging findings of the two conditions. MATERIALS AND METHODS We encountered eight cases of HHV-6 encephalopathy and nine cases of HSE. We divided an observation time into early, middle, and late periods defined as 0-2, 3-30, and more than 30 days from the onset of neurologic symptoms. Differences between HHV-6 encephalopathy and HSE on CT scans in the early period and in distribution and temporal changes in the affected regions on MR images in the three periods were analyzed. RESULTS At MRI in the early and middle periods, all eight patients with HHV-6 encephalopathy had exclusive involvement of the mesial temporal lobes, and all nine patients with HSE had involvement of both the mesial temporal lobes and the extratemporal regions (p < 0.01). Among patients who underwent head MRI, six of six with HHV-6 encephalopathy but none of six with HSE had resolution of high signal intensity on T2-weighted and FLAIR images (p < 0.01). Among patients who underwent head CT in the early period, none of the four with HHV-6 encephalopathy and six of the seven with HSE had abnormal findings, including parenchymal swelling, decreased attenuation of affected regions, and abnormal gyral enhancement (p < 0.05). CONCLUSION Serial MRI showed transient abnormal signal intensity in the mesial temporal lobes in patients with HHV-6 encephalopathy but persistent abnormal signal intensity in both the mesial temporal lobes and the extratemporal regions in patients with HSE. CT in the early period showed no abnormality in patients with HHV-6 encephalopathy but definite abnormal findings in patients with HSE. These differences may be useful in the differential diagnosis of the two conditions.

High b-value diffusion-weighted MRI in differentiation between benign and malignant polypoid gallbladder lesions.

Background Several studies have reported the effectiveness of high b-value diffusion-weighted MR imaging (DWI) in the abdominal region, and have found that various malignant tumors may show high signal intensity on DWI, reflecting their high cellularity and/or their long relaxation time. The value of ADC measurement has also been documented for the diagnosis of several abdominal malignancies. Purpose To retrospectively evaluate the usefulness of high b-value DWI in differentiating between benign and malignant polypoid gallbladder lesions. Material and Methods The study population consisted of 10 benign (three hyperplastic polyps and seven adenomas) and 13 malignant (all adenocarcinomas) polypoid gallbladder lesions. DWI was evaluated by two observers. Qualitatively, the signal intensity of the lesions on DWI was visually evaluated and categorized as iso, high, or very high. Quantitatively, the ADC values of the lesions were measured from ADC maps. Statistical analysis was performed using a two-tailed Fishers exact test and the Mann-Whitney test, respectively. Results Qualitative analysis revealed a statistical difference (P = 0.0041). Six of 10 benign lesions were categorized as iso, and the remaining four were categorized as high. In the 13 malignant lesions, one was categorized as iso, five as high, and seven as very high. The ADC values of the malignant lesions (1.34 ± 0.50 × 10–3 mm2/sec) were significantly lower than those of the benign lesions (2.26 ± 0.44 × 10–3 mm2/sec) (P = 0.00016). Conclusion High b-value DWI may be useful for differentiating between benign and malignant polypoid gallbladder lesions by the visual assessment of DWI and ADC measurement.