Using quadratic discriminant analysis, they determined if a window contained a true positive or false positive in a data set of ten patients. Lesion size mm 0—10 10—20 20—30 30—40 40—50 50—60 60—70 Training set Once Th C is determined, the contrast material is eliminated from within the C region by setting the gray level to 0 for all pixels whose gray level is greater than Th C. Lesions frequently demonstrate enhancement in the nephrographic phase and appear as filling defects Figure 9 or as an irregular luminal contour in the excretory phase. Conditions commonly referred for CTU include urinary calculus disease, hematuria, flank and abdominal pain, suspected renal or urothelial neoplasm, a variety of inflammatory conditions, and congenital anomalies of the kidneys and ureters. They used a rule-based system based on shape measures and uniformity measures to identify lesion candidates.

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The six features selected were normalized radial length area, rectangularity, area, average gray level, and two contrast features.

Detection of urinary bladder mass in CT urography with SPAN

Papillary necrosis is associated with analgesic overuse, sickle cell anemia, diabetes, pyelonephritis, renal obstruction, and renal vein thrombosis. Congenital anomalies of the kidneys and ureters Congenital anomalies of the kidneys, including horseshoe kidney, renal ectopia with or without crossed-fusion,hypertrophied column of Bertin, and renal agenesis sometimes with a genesis or cystic dilatation of the ipsilateral seminal vesicleare all well depicted by CT urography.

While diagnostic unenhanced and atlss acquisitions are relatively easy to obtain, optimal opacification and distention of the ureters during the excretory phase can be more problematic. As the contrast between the lesion and its surroundings is ct urography atlas smaller in the noncontrast region, a different method atls have to be developed for detection in the noncontrast region.


A variety of techniques have been proposed to improve visualization, including oral and Ct urography atlas hydration, diuretic administration, use of a compression belt, prone positioning, and a log-rolling prior to the excretory acquisition.

CT Urography: An Atlas – Google Books

The bladder wall of the C region was transformed into a wall thickness profile that was analyzed to determine lesion candidates. Assuming a Gaussian mixture distribution, multiple Gaussians were fit to the histogram for the training set [Fig.

The origin of this new coordinate system is defined at the top left of the profile, with Y -values increasing in the downward direction. We urograpuy maximum intensity projection MIP along uroggraphy slices of ct urography atlas bladder to estimate the upper boundary of the contrast-enhanced region.

CT urography: Review of technique and spectrum of diseases

The talas of the image was adjusted to better visualize the bladder wall. An Atlas Stuart G. It is important to correctly identify the type of bladder injury.

The average gray level, GL Avgis arlas into four different groups which are ct urography atlas to determine the initial threshold, Th initusing the following decision rules: The imaged bladders, along with their lesions, can assume a variety of shapes and sizes. With few exceptions, most notably that of the unenhanced CT performed for acute flank pain and stone disease, many urological symptoms and conditions are now investigated with CTU.

Multi-slice CT urography after cct injection: The lesion candidate voxels are then grouped into regions. Alderson is a Fellow in the Department of Radiology; Dr. The radiologist must pay close attention throughout the entire urinary tract as multiple lesions may be present.

The sensitivity of each ROI box change was estimated at the operating points used for the original box for the training 2. Chapters on abnormalities follow a case-based teaching file format.


My library Help Advanced Book Search. Detection of urothelial carcinoma is arguably ct urography atlas primary role of CT urography, be it in patients with hematuria or those with a history of urothelial tumors of the bladder requiring surveillance of the upper tracts. If the tumor obstructs a calyx, the calyx may appear irregular or amputated. The definitions of these features can be found in the literature.

As 3 CT scans of the abdomen and pelvis are performed in the examination, radiation dose to the patient is of concern. Clinical Departments CT urorgaphy The prescreening stage detected most of the true lesions, but also many false positive lesions.

State of the art.

CT urography: Review of technique and spectrum of diseases

The cases were split evenly into independent training and test sets. The arrow indicates the average GL of the first row that has value above the threshold and therefore identified as R 1. In these situations, talas patient can be placed in the prone position and ufography through the pelvis can be repeated. On the profile, pixels with heights larger than H are considered to be lesion candidate pixels [Figs.

Late complications include ureteral reflux with hydronephrosis, ureteral stricture, stone formation, pouch necrosis, and ct urography atlas recurrence.