Renal Ultrasound Studies Research Articles

Extracorporeal shock wave lithotripsy: impact on the radiology department of a stone treatment center.

Extracorporeal shock wave lithotripsy (ESWL) was performed on 925 patients (1,222 treatments) for 446 calyceal, 345 pelvic, 172 ureteral, and 108 staghorn calculi. ESWL necessitated 6.3 KUB and 1.2 renal ultrasound studies per treatment session. Intravenous urography was required in 6% of patients after ESWL. Percutaneous nephrostomy tube placement was performed by the radiologists in 10% of patients. Procedures related to nephrostomy tube placement included percutaneous nephrolithotripsy, tube changes, nephrostography, and stone fragment irrigations and retrievals. Staghorn calculi treatment with ESWL required the most procedures by radiologists (34% for partial staghorn and 56% for complete staghorn) compared with 3%, 8%, and 11% for calyceal, pelvic, and ureteral stones, respectively. In all, 8,478 radiologic examinations and procedures were performed pertaining to ESWL. This is approximately 35 studies per day. While this number may be high because it represents the early experience of the authors with ESWL, the impact on the radiology department can be substantial.

Factors associated with renal parenchymal echogenicity in the newborn.

A prospective renal ultrasound study of 134 newborns (49 prematures weighing less than 2500 g and 85 more mature babies) was undertaken to investigate factors associated with increased renal cortical echogenicity (RCE). Increased RCE was seen in 39 (29 per cent) babies. It was significantly related to body weight, age, medical status, blood urea nitrogen, and serum creatinine. In view of the interdependence of these factors, however, multivariate analysis was performed, which revealed that age was the most important factor associated with increased echogenicity (r = -0.46), and the other factors had only small independent effects, increasing the multiple r to 0.56. The authors conclude that an infant's immaturity is the most important determinant of increased RCE.

Family studies in tuberous sclerosis. evaluation of apparently unaffected parents

A family study was conducted to evaluate the apparently unaffected parents of 13 patients with tuberous sclerosis. None of the parents had a personal or family history suggesting the diagnosis of tuberous sclerosis. All 26 parents were examined according to a protocol that entailed medical history, physical examination (including Wood's lamp examination of the skin), funduscopic examination through a dilated pupil, roentgenograms of the hands, feet, and skull, renal ultrasound studies, and cranial computed tomography (CT). In these 13 families, three fathers and one mother had previously undiagnosed tuberous sclerosis. Three of the four had skin changes, three had calcifications shown by CT, and one had renal cysts. These data demonstrate the importance of detailed examination of all parents of patients with tuberous sclerosis before recurrence-risk counseling is given. (<i>JAMA</i>1983;249:1302-1304)

Family Studies in Tuberous Sclerosis

A family study was conducted to evaluate the apparently unaffected parents of 13 patients with tuberous sclerosis. None of the parents had a personal or family history suggesting the diagnosis of tuberous sclerosis. All 26 parents were examined according to a protocol that entailed medical history, physical examination (including Wood's lamp examination of the skin), funduscopic examination through a dilated pupil, roentgenograms of the hands, feet, and skull, renal ultrasound studies, and cranial computed tomography (CT). In these 13 families, three fathers and one mother had previously undiagnosed tuberous sclerosis. Three of the four had skin changes, three had calcifications shown by CT, and one had renal cysts. These data demonstrate the importance of detailed examination of all parents of patients with tuberous sclerosis before recurrence-risk counseling is given.

Pre- and Postoperative Renal Failure

The acute onset of oliguria and azotemia in the postoperative setting may be caused by pre-renal causes or intrinsic renal damage. The first step in arriving at a diagnosis is to review the history as noted above for clues regarding fluid balance, treatment with nephrotoxins, etc. The typical patient with prerenal azotemia will present with evidence of the recent onset of worsening of pre-existing cardiac disease, renal or gastrointestinal fluid loss, or the accumulation of acites, edema, or retroperitoneal fluid. In the absence of very recent diuretic therapy, he will be excreting a scant amount of concentrated (greater than 400 mOsm per L) sodium free (less than 10 to 20 mEq per L) urine. The serumBUN/Cr ratio is often greater than 15 to 20:1, and their urinary sediment will be bland. In an occasional patient in whom these studies give equivocal results, additional help may be obtained with measurements of central venous pressure (CVP) or pulmonary wedge pressure (PWP) and by noting their response to intravenous fluid loading. A rising CVP or PWP in the face of salt loading is, of course, evidence against prerenal azotemia. Patients with obstructive uropathies may be oligoanuric or polyuric-occasionally a characteristic alternating polyuria and oliguria is found (due to displacement of a stone or relief of edema). When oliguric their urine typically contains substantial amounts of sodium (greater than 20 mEq per L), is isotonic, and their OsmU:OsmP is les s than or equal to 1.2. Their urinary sediment will reflect the cause of their obstruction as noted above. A renal scan, ultrasound study, or infusion IVP are mandatory to rule out the possibility of obstructive uropathy. If these nonivasive studies are equivocal, one must consider doing a unilateral retrograde. The development of ATN usually occurs in the setting of hypotension, sepsis, dehydration, and with exposure to nephrotoxins. Most patients with be excreting scant amounts of isotonic urine containing more than 20 to 30 mEq per L of sodium. Their CrU:CrP is less than or equal to 20:1 and their urinary sediment reveals many epithelial cells and casts. Those patients with nonoliguric ATN have urine outputs which may exceed 2 liters per day. Despite this output they demonstrate a stepwise increase in serum urea and creatinine. Urine sodium and osmolality are not very helpful in this setting. Many such patients do have low (less than 20 mEg per L) urine sodium concentration and excrete isotonic urine.