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.     

Ultrasound versus excretory urography in evaluating acute flank pain

To determine the role of ultrasound (US) in patients with acute flank pain and suspected acute urinary tract obstruction, a prospective study was performed on 20 patients comparing US with emergency excretory urography. US was not as sensitive as excretory urography for diagnosing hydronephrosis, for detecting ureteral or renal calcification, or for diagnosing forniceal rupture. Although US is an effective screening modality for hydronephrosis in patients with chronic renal obstruction, it is not useful for evaluating patients with acute flank pain in whom acute obstruction may be present. In this group of patients, excretory urography remains the examination of choice.     

Digital radiography versus conventional radiography during excretory urography: our experience

The authors describe a computed radiographic system employed to generate and archive digital images in intravenous urography. For each exposure the system produces two digital images: the first (left image) simulates a conventional screen-film radiograph, the second (right image); enhances some spatial frequencies and emphasizes the margins of the structures. These images can be modified in their chief parameters and then printed by a laser-printer and archived on optical disks. Four experienced radiologists evaluated digital images with regard to some chief diagnostic parameters and, in 50 patients, they compared digital images with conventional screen-film radiographs and submitted the results to statistical analysis. For some of the chosen parameters, particularly for the evaluation of renal margins before and after contrast medium injection, digital images gave statistically better results than conventional films, while, no statistically significant different was observed for the other parameters. From the results of this preliminary study digital radiography was found to be useful in intravenous urography by reducing the patient's exposition dose, by always obtaining images of good quality, and by enhancing some particular features of the standard image; on the other hand there were many unsolved problems regarding the communicating and archiving system (PACS), because of the slowness of the image transfer procedure, difficulties in data transmission and complexity of referential procedures.     

Diagnostic value of diuretic-enhanced excretory MR urography in patients with obstructive uropathy

PURPOSE: Ultrasonography and conventional intravenous urography are most common methods in diagnosis of obstructive uropathies. The disadvantage of ultrasonography is inability of visualizing middle and lower one thirds of ureter, while intravenous urography is using radiation, also functionally extra loading effect on kidneys. In this study, the diagnostic value of MR urography on obstructive uropathy were investigated. MATERIALS AND METHODS: Forty five patients who were suffered from obstructive uropathy examined by ultrasonography, intravenous urography and diuretic-enhanced excretory MR urography by using MR-contrast-agent. RESULTS: MR urography established accuracy rate of 92.8% for stone diseases which formed the largest group in this study, however, in other causes of obstructive uropathy, MR urography provide 100% correct diagnosis. CONCLUSION: MR urography provide high quality images for diagnosing and determining causes of urinary obstruction defining position and severity of dilatations as well as showing localization of the pathology. We think that MR urography should be a primary investigation in patients with obstructive uropathy who have contrast agent and X-ray contrindication.     

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.     

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.     

Reducing the radiation dose during excretory urography: flat-panel silicon x-ray detector versus computed radiography

OBJECTIVE: The purpose of the study was to examine the possibilities for reducing radiation exposure in uroradiology using digital flat-panel silicon X-ray detector radiography. We compared the subjectively determined image quality of abdominal radiographs and urograms obtained on a digital flat-panel detector radiography system with those obtained on a computed radiography system. SUBJECTS AND METHODS. Fifty patients who had a clinical indication for urography underwent unenhanced abdominal imaging that was alternately performed using flat-panel silicon X-ray detector radiography or computed radiography. For patients who required a second radiograph with contrast medium, the examination modality was changed to avoid exposing the patients to excess radiation. The images obtained on flat-panel X-ray detector radiography were obtained at half the radiation dose of the images obtained on computed radiography (800 speed vs 400 speed). The resulting 50 pairs of images were interpreted by four independent observers who rated the detectability of structures of bone and the efferent urinary tract relevant to diagnosis and compared the image quality. RESULTS: At half the radiation dose, digital flat-panel X-ray detector radiography provided equivalent image quality of the liver and spleen, lumbar vertebrae 2 and 5, pelvis, and psoas margin on abdominal radiographs. The image quality obtained with digital flat-panel X-ray detector radiography of the kidneys, the hollow cavities of the upper efferent urinary tract, and the urinary bladder was judged to be statistically better than those obtained with computed radiography. CONCLUSION: With half the exposure dose of computed radiography, the flat-panel X-ray detector produced urograms with an image quality equivalent to or better than computed radiography.     

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.     

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.     

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.