Fluid restriction before excretory urography.

Despite a lack of hard evidence, many radiologists continue to support the use of fluid restriction before urography. Based on increasing the urinary contrast medium concentration, this has been shown to be a poor index for renal opacification. The usual overnight restriction produces no significant change in urine osmolality or opacification. Effective fluid restriction may produce a just detectable increase in pyelographic density but the nephrogram in unaffected, even by active hydration. Fluid restriction may occasionally result in inadvertent dehydration with serious or fatal reactions. Since it is ineffectual in improving the urogram and potentially hazardous, it should be abandoned.     

Modified excretory urography in prehysterectomy patients

A retrospective (520 patients) and prospective study (100 patients) of prehysterectomy patients was done to determine the role of preoperative excretory urography. Potentially useful information was provided by the urogram in only a small number of patients (7.4%). It is arguable whether or not preoperative intravenous urography should be done in these patients. However, since most of these patients routinely undergo this study, we suggest that a curtailed urogram consisting of a KUB film, a postinjection 15-minute prone film, and a supine film of the contrast-filled urinary bladder is adequate for preoperative screening, thereby minimizing cost and radiation to the patient.     

Limited use of hypertensive excretory urography

Clinical experience indicates that hypertensive excretory urography is not a satisfactory screening examination to detect patients having hypertension due to renal artery stenosis. Review of the Cooperative Study data indicates the false negative rate for screening was 21.8%. In addition, the prevalence of hypertension caused by renal artery stenosis appears quite low, in the range of 1–3%. Since the objective is to identify patients who will benefit from surgery, clinical sorting strategy should focus on evaluating patients as surgical candidates, not as having the disease. Once that is done, pharmacodynamic renal arteriography is recommended as the first imaging examination to find the renal artery lesion and determine its hemodynamic significance.     

Emergency excretory urography in blunt abdominal trauma

In a prospective study the authors correlated the degree of hematuria and of blunt abdominal trauma with the results of emergency excretory urography. Urograms were obtained for 37 patients who presented with blunt abdominal trauma, no gross hematuria and at least five erythrocytes per high-power field (hpf) on microscopic urinalysis. Microscopic hematuria was defined as an erythrocyte count of more than 5 and fewer than 50 per hpf. Major trauma was defined as shock (systolic blood pressure of less than 90 mm Hg), fracture of the lumbar spine, the pelvis or the lower ribs, ecchymosis in the flank or acute abdominal injury. Contusions and small subcapsular hematomas were defined as nonsignificant renal injuries; all other renal injuries were defined as significant. Of 17 patients with minor blunt abdominal trauma 14 had fewer than 50 erythrocytes per hpf; none of these had a significant renal injury, whereas 1 of the 3 with more than 50 erythrocytes per hpf did have a significant injury. Of 20 patients with major trauma 5 had a significant renal injury. The authors conclude that microscopic hematuria associated with blunt abdominal trauma but without shock or major nongenitourinary injury does not warrant routine excretory urography.     

Liver metastases discovered during high-dose excretory urography

Liver metastases were discovered in 4 adults during high-dose excretory urography with upper abdominal tomograms. Previous reports in the English literature have noted incidental discovery of hepatic cysts or abscesses during urography, but no documented cases of liver metastases were found. All metastases were visualized as round, lucent, hepatic filling defects during total body opacification. Radiologists performing high dose excretory urography with tomography should routinely scrutinize the hepatogram, because metastases, cysts, or abscesses may be visualized. Final diagnosis of these masses usually depends on additional diagnostic modalities.     

Significance of paravertebral venous collaterals on excretory urography

The visualization of paravertebral venous collateral vessels during excretory urography may be normal when a foot vein has been injected. This finding reflects the abundant intercommunications between the caval, vertebral, and azygos venous systems and should not be mistaken for vena caval occlusion unless strong clinical suspicion of deep venous thrombosis exists.     

Medullary rays. Visualization during excretory urography.

The medullary rays are well-defined anatomic structures consisting of bundles of renal tubules which form in the renal cortex and continue through the renal medulla as the medullary striations. These structures are occasionally visualized during excretory urography in abnormal physiologic states characterized by tubular stasis and hyperconcentration of contrast material. Under these conditions, fine striations are visualized which correspond in position and orientation to these structures. The work of others has shown that in tubular stasis, contrast material is hyperconcentrated in the tubules. On microradiography in normal and obstructed kidneys, the highest concentrations of contrast material are seen in the lumen of collecting ducts. Lastly, retrograde injection of contrast material into the medullary rays produces a roentgen image similar to our illustrated cases.     

Iohexol for excretory urography: a comparative study

A new iodinated nonionic contrast agent (Iohexol) was compared to an ionic contrast agent (renografin 60) in a double-blind study. Fifty-five patients with normal renal function were studied for incidence of undesirable side-effects and quality of the resultant excretory urogram. No major adverse reactions occurred. Minor side-effects due to the contrast occurred more than two times as often with Renografin than when Iohexol was used. The quality of visualization of the collecting system on urography was considered excellent in 44% of the patients receiving Iohexol as compared to a 17% frequency when Renografin was used.     

Radiographic findings and hypotensive reactions in excretory urography

The radiographic findings and the hypotension patterns were reviewed in 19 patients having hypotensive reactions in routine excretory urography using ionic contrast medium. The lowest systolic blood pressure was above 80 mmHg in 10 patients while below 80 mmHg in remaining 9 patients. The urogram was unremarkable as long as the systolic blood pressure was preserved above 80 mmHg. In 2 patients, whose systolic blood pressure decreased quickly beyond 80 mmHg immediately after injection of contrast medium, the pyelogram was faint or non-visualized. On the other hand, in 4 patients, whose systolic blood pressure decreased beyond 80 mmHg in several minutes after injection of contrast medium and remained under 80 mmHg for more than 20 minutes, the nephrogram was dense and the pyelogram was faint or non-visualized. Although systolic blood pressure decreased beyond 80 mmHg, the urogram was unremarkable in 3 patients. This was due to the delayed hypotension or the short duration of hypotension.     

The value of post-void radiographs in excretory urography

For years, urologists and radiologists have had differing opinions on the value of post-void radiographs in excretory urography. This report is based on a questionnaire sent to the members of the Association of University Urologists and the Society of Uroradiologists. Satisfactory evaluation of bladder function by the use of post-void radiographs is not always possible. Nevertheless, such radiographs have value in selected cases and often play a major role in determining future therapy.