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Biomedical subjects

M Kunin

Publications and source records attributed to M Kunin.

6 recordsLinked to original sources

The encased ureter: bullet and bodkin pattern, a reliable radiographic sign.

Among the causes of constricted ureter is benign or malignant encasement. The diagnosis of ureteric encasement is frequently overlooked, even by well informed clinicians and radiologists. The most common benign cause is retroperitoneal fibrosis and the most frequent malignant causes are extension from an adjacent primary tumour, true metastases to the ureter and lymphoma. Lack of recognition of the process may lead to mistaken diagnosis of an inflammatory stricture or infiltrating transitional cell tumour, with resultant inappropriate management. A sign which appears to be almost specific for encasement, the bullet and bodkin configuration, is described here. Newer imaging modalities such as computed tomography and ultrasound, while helpful, are probably less sensitive and less specific than the retrograde ureterogram because a detectable mass is not always present.

Humans

Visual contrast enhancement with a patterned overlay.

A dot-screen pattern was devised and superimposed on computed tomography images to improve contrast at a viewbox. The phenomenon is believed to be probably related to lateral inhibition. To evaluate its usefulness, the device was used on 12 images (eight showed metastatic liver lesions, and four were normal); each image was viewed without the device by ten observers. Three control images were viewed a second time without the device. The remaining nine images were viewed a second time with the device. The overlay improved diagnostic performance in nine observers. Sensitivity improved by 12%, and confidence in true-positive findings increased by 41.6%. Forty-five percent of false-negative findings were converted to true positive with the use of the overlay.

Humans

Bridging septa of the perinephric space: anatomic, pathologic, and diagnostic considerations.

The perinephric space is not a simple fat-filled chamber through which fluid may be distributed unhindered. It is divided into multiple compartments by fibrous lamellae, the bridging septa. Some of these structures arise from the renal capsule and extend to the perinephric fascia; others are attached only to the renal capsule and are arranged more or less parallel to the renal surface. Still others connect the anterior to the posterior leaves of the perinephric fascia. The resulting compartments exert an important influence on pathologic processes, resulting, for example, in limitation of the spread of pus and tamponade of bleeding points. The configuration of many perinephric collections can only be understood by knowledge of the existence and arrangement of these lamellae. The current criteria for differentiation of subcapsular from perinephric hematomas are shown to be in error, and a new sign for such differentiation is described. There are also implications regarding therapeutic drainage of perinephric abscesses, particularly by the percutaneous route. A new classification of the perinephric fascia is proposed.

Abscess

Concentric folds in the bladder: a new sign of chronic outlet obstruction and neurogenic bladder.

The finding of concentric folds in the bladder on excretory urography is a hitherto unreported but reliable sign of chronic urinary retention, usually due to outlet obstruction or neurogenic bladder. In a study of 152 consecutive patients with urinary retention, the presence of typical concentric folds alone was found to be as common and, therefore, as sensitive an indicator as trabeculation. The sign is useful in evaluating the significance of the incompletely emptied bladder on the post-void film, and in detecting unsuspected disease. A false-positive rate of 1.5% was found in a control series of 190 women, and no false-positive findings were seen in 214 men concurrently studied. A hypothesis concerning the mechanism of concentric fold formation is advanced.

Chronic Disease