Obstructive vs nonobstructive dilatation of the renal collecting system in children: distinction with duplex sonography.

OBJECTIVE: The resistive index in cortical or arcuate renal arteries of children was calculated to determine whether obstructive uropathy could be differentiated from nonobstructive dilatation. SUBJECTS AND METHODS: Kidneys (n = 176) were prospectively evaluated by using duplex Doppler sonography in patients 3 days to 20 years old. Obstruction was confirmed by renography with furosemide and/or by surgery. RESULTS: The normal resistive index was 0.57 +/- 0.06 and the normal difference in resistive indexes between kidneys was 0.03 +/- 0.02 (n = 15). Abnormal values indicative of ureteropelvic junction obstruction were defined as the normal mean +/- 2 SD (i.e., a resistive index of > or = 0.70 plus a difference in resistive indexes between kidneys of > or = 0.08). Patients with unilateral dilatation and obstruction at the ureteropelvic junction (n = 20) had a mean resistive index of 0.77 +/- 0.05 and a difference in resistive indexes between kidneys of 0.16 +/- 0.05 (p < .001 compared with patients with normal kidneys and p < .001 compared with patients with unilateral dilatation without obstruction). Patients with unilateral dilatation but without obstruction (n = 16) had a mean resistive index of 0.63 +/- 0.06 and a difference between kidneys of 0.06 +/- 0.04 (values within normal limits). The positive and negative predictive values of the obstruction criteria for unilateral collecting system dilatation were 95% and 100%, respectively. After successful surgical correction of ureteropelvic junction obstruction (n = 29), patients had a normal mean resistive index of 0.61 +/- 0.05 and a normal difference between kidneys of 0.03 +/- 0.03. Five patients examined both before and after surgery showed a statistically significant drop in the resistive index of the obstructed kidney (0.75 +/- 0.03 to 0.65 +/- 0.05, p < .05) after surgery and a small rise in the resistive index of the contralateral kidney (0.56 +/- 0.04 to 0.63 +/- 0.04, p < .02). CONCLUSION: The resistive index appears to be an effective parameter for the evaluation and follow-up of unilateral obstructive or nonobstructive ureteropelvic junction dilatation in children.

MR imaging of spinal dysraphism.

Spinal dysraphism includes anomalies of midline fusion involving bony, mesenchymal, and neural elements. MR imaging of the spine was performed as the initial imaging technique to determine its role in the evaluation of 31 children when spinal dysraphism was clinically suspected or when radiographs revealed errors of ossification of the posterior elements (spina bifida). Correlation of surgical findings in 17 of 18 abnormal examinations and metrizamide myelography with CT in six of these cases indicated that accurate diagnosis was provided by MR in all instances. Examples of spina bifida aperta (spina bifida cystica)--including myelomeningocele, myelocystocele, and lipomyelomeningocele--and those of occult spinal dysraphism--such as dorsal dermal sinus, spinal lipoma, and tight filum terminale (thickened filum)--are presented. These cases show MR to be a reliable technique in the initial evaluation of these disorders.

Three-dimensional CT reformation in children.

Three-dimensional computed tomographic (CT) reformation has proven useful in the evaluation of congenital malformations of the brain as well as in the surgical approach and postoperative assessment of craniofacial anomalies in children. This technique was performed on 41 patients, of whom eight are presented. The congenital anomalies of semilobar holoprosencephaly and colpocephaly are described. Six representative cases of craniofacial anomalies with pre- and postoperative examinations include Crouzon syndrome, orbital fibrous dysplasia, frontonasal encephalocele, cranial involvement from neurofibromatosis, Treacher-Collins syndrome, and a Tessier III facial cleft. Addition of the dimension of depth provides a view heretofore not obtainable by standard imaging techniques and allows more accurate diagnosis as well as a more specific approach to surgical planning and follow-up.

Holoprosencephaly classified by computed tomography.

Five cases are presented to demonstrate the computed tomographic (CT) spectrum of holoprosencephaly. The classifications of alobar, semilobar, and lobar types A and B holoprosencephaly are each represented, with an additional case of semilobar holoprosencephaly complicated by a subdural effusion.

Real-time sonographic detection of vesicoureteral reflux in children.

Real-time sonography and the principle of contrast sonography were used for evaluation of vesicoureteral reflux in children. Fifty-five kidneys were examined during the filling phase of cystourethrography. Of 15 positive cystograms, with grade II or greater reflux, 13 sonograms were positive. A positive sonogram was defined as visualization of moving microbubbles within the renal collecting system and/or dilatation of the collecting system during the course of bladder filling. This method may prove to be of value in the management of children with vesicoureteral reflux, particularly because sonography provides good visualization of renal size and parenchymal scarring while simultaneously demonstrating reflux.