Case of Isolated Absence of the Azygos Vein: Evaluation Using Photon-counting Detector CT.

The isolated absence of the azygos vein was incidentally found on computed tomography (CT) examination in a 60-year-old female. The exact anomaly can be evaluated on high-resolution images of 0.4-mm slice thickness with low keV using photon-counting detector CT. The azygos vein, including the azygos arch, was absent, and a mildly dilated hemiazygos vein flowed to the left brachiocephalic vein through the left superior intercostal vein. A hemiazygos vein connected the left renal vein at the level of the first lumbar vertebra. This patient was the second patient to undergo evaluation using volume rendering images. High-resolution maximum-intensity projection images were useful for assessing the anatomy. Radiation dose was decreased compared with that in conventional CT.

Simultaneous Visualization of the Thoracic Duct and Blood Vessels Using MRI: A Comparison Between Balanced Turbo-field-echo and Spin-echo.

OBJECTIVE: Magnetic resonance thoracic ductography (MRTD), concomitant with blood vessel imaging, provides useful anatomical information. The purpose of this study was to assess the visibility of the thoracic duct and blood vessels simultaneously by MRTD using balanced turbo-field-echo (bTFE) and turbo spin-echo (TSE). METHODS: MRTDs concomitant with blood vessel imaging on bTFE and TSE were obtained for 10 healthy volunteers with a 1.5T-magnetic resonance unit. Visibility of the thoracic duct, blood vessels in the thoracic region; motion artifacts; and overall image quality were scored by two radiologists using three-to-five-point scales; those were compared between bTFE and TSE. RESULTS: The thoracic duct was generally well-visualized on MRTD sequences. The upper part of the thoracic duct was better visualized on TSE than on bTFE (p < 0.05). The blood vessels were well visualized on bTFE and TSE; the bilateral subclavian arteries and the right subclavian veins were better visualized on TSE than on bTFE (all p < 0.05). Motion artifacts and overall image quality were better on TSE than on bTFE (p = 0.0039 and 0.0020, respectively). CONCLUSION: MRTD concomitant with blood vessel imaging on TSE has better visibility of the thoracic duct and blood vessels than bTFE.

Automatic detection of punctate white matter lesions in infants using deep learning of composite images from two cases.

Punctate white matter lesions (PWMLs) in infants may be related to neurodevelopmental outcomes based on the location or number of lesions. This study aimed to assess the automatic detectability of PWMLs in infants on deep learning using composite images created from several cases. To create the initial composite images, magnetic resonance (MR) images of two infants with the most PWMLs were used; their PWMLs were extracted and pasted onto MR images of infants without abnormality, creating many composite PWML images. Deep learning models based on a convolutional neural network, You Only Look Once v3 (YOLOv3), were constructed using the training set of 600, 1200, 2400, and 3600 composite images. As a result, a threshold of detection probability of 20% and 30% for all deep learning model sets yielded a relatively high sensitivity for automatic PWML detection (0.908-0.957). Although relatively high false-positive detections occurred with the lower threshold of detection probability, primarily, in the partial volume of the cerebral cortex (≥ 85.8%), those can be easily distinguished from the white matter lesions. Relatively highly sensitive automatic detection of PWMLs was achieved by creating composite images from two cases using deep learning.

Delayed Enhancement of Ascites after Iodine Contrast Administration Assessed with Dual-energy Computed Tomography: A Case Report.

We report a case of 71-year-old woman with lung cancer and high-attenuation ascites (HAA) due to iodine contrast material (ICM). The patient underwent two sequential CT scans at interval of 4 h between examinations by using ICM. The second scan was obtained by dual-energy CT (DE-CT), yielding the virtual non-contrast (VNC) image and iodine map, which were used to evaluate HAA. The VNC image revealed ascites with water density, and HAA was thought to contain iodine because the attenuation of ascites around the liver was similar to that of the spleen on the iodine map. The VNC image and iodine map using DE-CT were useful in differentiating HAA due to iodine (delayed enhancement of ascites) from hemorrhagic ascites in this patient.