Biomedical subjects
Publications and source records attributed to R O Bude.
Milk of calcium in the kidney is usually found in association with hydronephrosis or caliceal diverticula. A case of milk of calcium in a renal cyst is presented. Contiguity with an adjacent rib can make it difficult to detect the dependent layered milk of calcium.
It has recently been suggested that the resistive index (RI) in native kidneys of healthy children is age dependent; however, this relationship has not been completely defined or explained. In 110 kidneys in 71 healthy children aged newborn to 11 years, RIs were determined from peripheral sites (presumed to be arcuate, cortical, or distal interlobar arteries). The authors found the normal renal RI (the mean RI in each kidney) to be age dependent. The renal RI in children is commonly elevated above the upper normal limit in adults (0.70) in the 1st year of life, and the overall trend shows a decrease with age. From 4 years on, the likelihood is low (2% probability) that the RI is above 0.70. Variability of the renal RI from individual to individual was most marked in the first 6 months of life, with 51% (19 of 37) of these kidneys having an RI that would be considered abnormal by adult standards. It is concluded that the normal renal RI is age dependent, with an overall decreasing trend with increasing age. This age dependency of the renal RI and, hence, of the renal vascular resistance might be dependent on levels of active renin, as the maturational profile of the renal RI more closely parallels that of active renin than those of other renal functional parameters.
OBJECTIVE: We evaluated the location of the umbilicus relative to the aortic bifurcation and the left common iliac vein where it crosses the midline. METHODS: Abdominal computed tomography images from 35 reproductive-age women were retrospectively reviewed to determine the location of the umbilicus. The results were correlated with body mass index using Pearson correlation coefficient and a two-tailed paired t test. RESULTS: The location of the umbilicus, but not the aortic bifurcation, was more caudal in heavier women and negatively correlated with body mass index. In nonobese women, the mean location of the umbilicus was 0.4 cm caudal to the aortic bifurcation, and was at or cephalad to the bifurcation in eight of 15 (53%). In overweight women, the mean umbilical location was 2.4 cm caudal to the bifurcation, and in obese women, 2.9 cm caudal to the bifurcation. In the last two groups of subjects, the umbilicus was located at the level of the bifurcation in six of 20 (30%). In every case, the umbilicus was located cephalad to where the common iliac vein crossed the midline. CONCLUSIONS: The umbilicus is often located at or cephalad to the aortic bifurcation, and consistently located cephalad to where the left common iliac vein crosses the midline. The laparoscopic approach should take these relationships into account to minimize injuries to major retroperitoneal vessels.
Two patients with ileal loop urinary diversions, studied with real-time and Doppler sonography ("duplex sonography") of the kidneys, were shown to have dilated intrarenal collecting systems. Resistive index measurements calculated from the Doppler signal correctly identified obstructive dilatation in 1 case and nonobstructive dilatation in the other.
Clean and dirty shadowing are common phenomena in ultrasound (US) imaging. Clean shadowing is thought to be produced by sound-absorbing materials (ie, stones), and dirty shadowing is thought to be produced by sound-reflecting materials (ie, abdominal gas), but these properties are not consistent. To evaluate the characteristics of shadows behind different objects at US, the authors scanned two renal stones and a bovine femur (each of which had part of its surface artificially smoothed or roughened) and a tissue-mimicking phantom comprising air-containing cylinders of different radii of curvature. The rougher and/or smaller the radius of curvature of the surface insonified by the sound beam, the cleaner was the shadow, independent of the composition of the underlying reflecting medium. Clean and dirty shadowing were primarily related to the properties of the surface of the shadowing object and provided little information about the structural nature of the object.
Laparoscopic complications are most often related to insertion of the Veress cannula or primary trocar. We evaluated the midline abdominal walls of 33 women using magnetic resonance imaging (MRI) or computed tomography to determine if the location and angle of placement of the Veress cannula and primary trocar should be chosen according to the patient's weight to minimize the risk of both preperitoneal placement and retroperitoneal vessel injury. The anterior abdominal wall thickness was measured for three standard approaches used for placement of laparoscopic instruments through the umbilicus at both 45 degrees and 90 degrees from the horizontal. In addition, the distance from the base of the umbilicus to the retroperitoneal vessels was measured. We found that in the nonobese patient, both the Veress cannula and primary trocar can be inserted at 45 degrees, at either the lower margin or base of the umbilicus, with little risk of preperitoneal placement or major vessel injury. In the overweight patient the cannula and trocar can still be inserted at 45 degrees, but placement through the base of the umbilicus rather than the lower margin will minimize the chance of preperitoneal placement. In the majority of obese patients it is only by placing both the Veress cannula and sharp trocar through the base of the umbilicus at or near 90 degrees that preperitoneal placement can be avoided. Alternatively, an open laparoscopic technique can be considered in such high-risk patients to decrease the risk of major vessel injury.