MR imaging of renal cell carcinoma: associations among signal intensity, tumor enhancement, and pathologic findings.

The purpose of this study was to compare the MR characteristics of renal cell carcinomas against histologic findings and to assess the correlations among signal intensity, tumor enhancement, and pathologic findings. Fifty-four patients (56 lesions) were examined by MR imaging and then underwent partial or radical nephrectomy. The pathologic diagnosis of all lesions was renal cell carcinoma. All MR examinations were performed as dynamic studies using the same 1.5-T scanner. MR characteristics were compared against pathologic findings after resection, and the correlations among signal intensity, tumor enhancement, and pathologic findings were then assessed. A significant correlation was observed between tumor grade and tumor enhancement, with G3 lesions tending to show little enhancement. Regardless of the histologic classification, G3 tumors were found to contain highly heterotypic cancer cells and very few vessels by histopathologic examination. No significant correlations were noted between the other MR characteristics and pathologic findings. Renal cell carcinomas showing little enhancement tend to be highly malignant lesions based on the pathologic findings. Special consideration is required for these tumors with regard to the selection of surgical intervention and follow-up observation.</p

Serial MRI Features of Canine GM1 Gangliosidosis: A Possible Imaging Biomarker for Diagnosis and Progression of the Disease

GM1 gangliosidosis is a fatal neurodegenerative lysosomal storage disease caused by an autosomal recessively inherited deficiency of β-galactosidase activity. Effective therapies need to be developed to treat the disease. In Shiba Inu dogs, one of the canine GM1 gangliosidosis models, neurological signs of the disease, including ataxia, start at approximately 5 months of age and progress until the terminal stage at 12 to 15 months of age. In the present study, serial MR images were taken of an affected dog from a model colony of GM1 gangliosidosis and 4 sporadic clinical cases demonstrating the same mutation in order to characterize the MRI features of this canine GM1 gangliosidosis. By 2 months of age at the latest and persisting until the terminal stage of the disease, the MR findings consistently displayed diffuse hyperintensity in the white matter of the entire cerebrum on T2-weighted images. In addition, brain atrophy manifested at 9 months of age and progressed thereafter. Although a definitive diagnosis depends on biochemical and genetic analyses, these MR characteristics could serve as a diagnostic marker in suspect animals with or without neurological signs. Furthermore, serial changes in MR images could be used as a biomarker to noninvasively monitor the efficacy of newly developed therapeutic strategies

The Late Phase/Early Phase Ratio of Pancreatic CT Values as a Novel Predictor of Pancreatic Fistula after Distal Pancreatectomy

Post-operative pancreatic fistula (POPF) remains the most common complication after distal pancreatectomy (DP). In this retrospective study, we reviewed the data from patients who underwent DP between 2008 and 2019 in our institute to determine whether the late phase/early phase ratio (L/E ratio) by preoperative computed tomography (CT) scan in the pancreas could predict POPF occurrence after DP. We examined the relationship between preoperative or intraoperative factors and the occurrence of POPF after DP using statistical methods in 23 males and 21 females with a mean age of 73. The mean L/E ratio was significantly lower in the POPF group than the non-POPF group (p=0.035). The L/E ratio had moderate diagnostic accuracy, with a calculated optimal cutoff value of 0.77. In univariate analysis, a significant association was noted between POPF and stump thickness ≥ 16.9, body mass index ≥ 27.5, and L/E ratio ≤ 0.77. In the multivariate analysis, the L/E ratio (odds ratio, 5.96; p=0.036) was an independent risk factor for POPF. Our findings suggest that the pancreatic L/E ratio may predict the occurrence of POPF after DP. This measure may be useful in preoperative risk stratification, patient counseling, and perioperative patient management, improving clinical outcomes after DP

Kinematic magnetic resonance imaging (MRI) of the normal shoulder: assessment of the shapes and signals of the superior and inferior labra with abductive movement using an open-type imager.

A preliminary study was conducted to evaluate the superior and inferior glenoid labra with abductive movement using an open-type MR unit in asymptomatic healthy volunteers. Both fast low angle shot (FLASH) and turbo spin echo (TSE) images were obtained to evaluate the shapes of both the superior and inferior labra, as well as to assess changes in signal at these sites. As the abduction angle was increased, the shape of the superior labrum changed from round or triangular to crescentic and a higher signal was frequently seen. At an abduction angle of 150 degrees, an increase in signal was seen in one-half of the superior labra; this increase was noted more frequently in volunteers over 40 years of age. In some of the superior labra, the increase in signal seen at 150 degrees abduction disappeared on subsequent images obtained at 0 degrees abduction. Hence, the increase in signal was considered to be a reversible change. The shape of the inferior labrum tended to change from crescentic to triangular or round. An increase in signal in the inferior labrum was unrelated to the abduction angle. Abductive kinematic studies using an open-type MR unit provides information about the morphology of the superior and inferior labra, as well as information about signal changes occurring at these sites.</p

Development of a novel artificial intelligence algorithm to detect pulmonary nodules on chest radiography

Background: In this study, we aimed to develop a novel artificial intelligence (AI) algorithm to support pulmonary nodule detection, which will enable physicians to efficiently interpret chest radiographs for lung cancer diagnosis. Methods: We analyzed chest X-ray images obtained from a health examination center in Fukushima and the National Institutes of Health (NIH) Chest X-ray 14 dataset. We categorized these data into two types: type A included both Fukushima and NIH datasets, and type B included only the Fukushima dataset. We also demonstrated pulmonary nodules in the form of a heatmap display on each chest radiograph and calculated the positive probability score as an index value. Results: Our novel AI algorithms had a receiver operating characteristic (ROC) area under the curve (AUC) of 0.74, a sensitivity of 0.75, and a specificity of 0.60 for the type A dataset. For the type B dataset, the respective values were 0.79, 0.72, and 0.74. The algorithms in both the type A and B datasets were superior to the accuracy of radiologists and similar to previous studies. Conclusions: The proprietary AI algorithms had a similar accuracy for interpreting chest radiographs when compared with previous studies and radiologists. Especially, we could train a high quality AI algorithm, even with our small type B data set. However, further studies are needed to improve and further validate the accuracy of our AI algorithm

Successful transcatheter arterial embolization of asymptomatic aneurysm associated with left inferior phrenic artery-to-left pulmonary artery fistula: A case report

Cases of inferior phrenic artery-to-pulmonary artery fistulas and those complicated by massive hemoptysis have been rarely reported. A 38-year-old man presented to our hospital with a chief complaint of coughing. Computed tomography (CT) revealed a nodule in the left lower lobe, and contrast-enhanced CT showed inflow of contrast medium into the nodule. CT angiography detected an aneurysm associated with a left inferior phrenic artery-to-left pulmonary artery fistula. Transcatheter arterial embolization (TAE) was performed to prevent hemoptysis. Hemoptysis did not occur during the 2-year follow-up. We report a rare case of asymptomatic aneurysm associated with a left inferior phrenic artery-to-left pulmonary artery fistula, which was successfully treated using TAE to prevent hemoptysis