Results: Stone size greater than 0.67 centimeters and location in the proximal ureter were found to be statistically significant in predicting complications. When individualizing operative complications with stone characteristics, a stone density of 817 Hounsfield units (HU) or greater, stone size of 0.79 centimeters or greater, and operative time greater than 53 minutes all showed statistical ...

A major problem in magnetic resonance imaging (MRI) is the lack of a pulse sequence dependent standardized intensity scale like the Hounsfield units in computed tomography. This affects the post processing of the acquired images as, in general, segmentation and registration methods depend on the observed image intensities. Different approaches dealing with this problem were proposed recently. I...

False-negative results of coronary artery calcium score (CACS) are common due to small calcified lesions being missed using a 3-mm slice thickness, a threshold of 130 Hounsfield units (HU) and a minimum area of 1 mm(2) for defining a calcified plaque. In contrast, false-positive results of CACS, as verified by a lack of coronary artery calcifications in computed tomography coronary angiogram (C...

Seven patients are reported with calcification in brain metastases. The calcification was punctate, curvilinear, or amorphous and sometimes closely simulated a hemorrhage. The attenuation values were 50-105 Hounsfield units before administration of contrast material. Although various degrees of contrast enhancement were noted in the noncalcified parts of the metastases, slight or no enhancement...

A 45-yr-old woman was admitted to excise a solid hepatic tumor which was incidentally detected at ultrasound examination for an unrelated reason. Preoperative differential diagnoses included primary or secondary malignant hepatic tumors or adrenal cortical carcinoma due to aggressive imaging features. The patient underwent adrenalectomy and partial hepatectomy. The tumor proved to be an adrenal...

The aim of this study is to examine the influence threshold-based segmentation on mean error automatic landmark detection in 3D CBCT images. A GUI was developed for radiologists, allowing manual identification and visualization After a segmentation, semi-automatic algorithm designed using anatomic definition each landmark. step 50 Hounsfield units used threshold variation assess error. 5 images...