Excretory urography in current practice: evidence against overutilization.

Excretory urography could be performed less frequently if some combinations of genitourinary signs and symptoms were found to be predictive of either a specific disease or normality. To explore this possibility, the authors conducted a prospective study involving more than 3,000 patients at three institutions (a teaching hospital, a community hospital, and a health maintenance organization). Predictive algorithms were obtained by application of a polychotomous logistic regression model but did poorly at differentiating normal from abnormal patients or arriving at a specific diagnosis. Selection of patients on the basis of the logistic model would have required testing 90% of all patients in order to detect 95% of those with abnormal urograms. These results suggest that current clinical selection criteria for excretory urography are effective, and that present frequency of utilization is appropriate.

Cystic dilatations of the upper urinary tract: a radiologist's developmental model.

The ureteral bud in the embryonic kidney grows and branches dichotomously for 15 generations. This branching tree is modified by a series of narrowings and expansions and becomes the ureter, the renal pelvis, the calyces, and the collecting tubules. Simultaneously, the ureteral bud induces the formation of nephrons. If many of the renal cystic diseases and congenital dilatations of the renal pelvis and ureter are viewed as a series of growth disturbances along the branching ureteral bud, their morphology and pathophysiology become clarified even though their etiology is often not known.

Intravenous urography: important adjunct for diagnosis of bladder tumours.

The intravenous urogram (IVU) has long been considered important for the evaluation of haematuria. A retrospective review of 64 patients with haematuria and subsequent histologically proven carcinoma of the bladder revealed that bladder tumours could be diagnosed pre-operatively in 34 of 46 (76%) of patients with gross haematuria and 12 of of 18 (67%) of those with microhaematuria. Fifteen of 20 IVUs available for review disclosed filling defects on the post-void view in 15/15 (100%), the anteroposterior view in 13/15 (87%), and the oblique view in 7/14 (50%). The IVU, especially the post-void view, permits pre-operative detection of bladder tumours in a majority of patients and can alert the clinician to the need for urgent cystoscopy.

Internal derangements of the temporomandibular joint: diagnosis by direct sagittal computed tomography.

The authors performed direct sagittal computed tomography (CT) on 4 cadaver temporomandibular joints (TMJ) and examined 51 TMJs in 47 patients clinically. The results were correlated with cadaver anatomical sections and clinical arthrographic findings. A fat plane between the bellies of the lateral pterygoid muscles, termed the "lateral pterygoid fat pad," served as the anatomical basis for detection of internal derangements by CT. CT was 94% accurate in detecting meniscal derangements and 96% accurate in detecting degenerative arthritis. The authors suggest that CT rather than arthrography be employed as the primary TMJ imaging modality when internal derangement or arthritis is suspected.

Recognition of bladder tumors by excretory urography.

Bladder tumors initially may be diagnosed by excretory urography in patients undergoing the examination because of specific symptoms or unrelated complaints. Among seven strategies tested by six experienced readers, the combination of early, full-bladder, and postvoiding anteroposterior radiographs was most successful in identifying bladder tumors in a series including 20 cases of biopsy-proved bladder tumor and 19 cases of cystoscopically normal bladders. The postvoiding radiograph, when viewed alone, was the single most valuable projection, and resulted in the correct diagnosis of 14 cancers that were not appreciated on any other single radiograph for a given case. The addition of oblique projections to the other three views did not significantly increase diagnostic sensitivity.

Absence of a persistent nephrogram in experimental acute renal failure.

Studies showing diminished cortical perfusion and reduced glomerular filtration in acute renal failure are apparently at odds with reports of a persistent nephrogram during urography in this disease. We followed the progression of nephrograms in eight dehydrated normal rats, in seven dehydrated rats treated with 12 mg/kg of mercuric chloride (nephrotoxic acute renal failure), and in nine dehydrated rats receiving 5 g/kg of IM-glycerol (myoglobinuric acute renal failure). To assess the capacity of our technique to identify a persistent, dense nephrogram, hemorrhagic hypotension (mean arterial pressure, 55-70 mm Hg) was induced in three rats. All rats showed nephrograms on magnification radiographs 1 minute following the injection of 1 cc/lb of sodium diatrizoate. Duplicate coded readings showed no prolongation of nephrograms in ARF-affected animals. Only the hypotensive rats manifested nephrograms on 2-hour radiographs. Some differing characteristics of nephrograms among the groups are explainable on the basis of differences in renal blood flow, as determined in separate experiments. Our findings would favor a preglomerular mechanism as the cause of oliguria in acute renal failure.

The selection of patients for excretory urography.

Symptoms, signs, and laboratory findings that indicated excretory urography in 1,622 patients, were compared with the radiographs. The chance that an indication would be associated with demonstrable disease was calculated. No "low-likelihood" indications could be identified. Elimination of the urograms obtained for any of the indications would not have been possible without simultaneously precluding detection of many diseased patients. The monetary cost of case-finding was low, and the efficacy of patient referral high.

Criteria for examination of the urethra during excretory urography.

Of 2,234 patients, 97 (4.3%) had symptoms suggesting of urethral diseases, and underwent excretory voiding urethrography (EVU) as part of their excretory urographic examination. Successful EVU examinations were obtained in 84 (87%); 43 (51%) had abnormal findings; 29 (34%) were normal; and 12 (12%) were considered probably normal, with no further study required. The additional portion of the study can be accomplished without a significant increase in examination time and without excessive additional imaging; it avoids the risks of catheterization.

The value of compression during excretion voiding urethrography.

Voiding urethrography with compression of the urethral meatus was evaluated as part of excretory urography in patients with symptoms involving the lower urinary tract. Meatal compression permits distension of the urethra distal to any area of increased resistance to flow, obviating the need for retrograde urethrography. The examination can be performed as part of routine excretory urography and avoids the hazards of urethral catheterization. In selected patients, excretion voiding urethrography with compression has given as much information as the combination of noncompression voiding urethrography and retrograde urethrography.

Renal microvasculature following papillary resection.

Surgical papillectomy was performed on 39 rabbits. Microvasculature initially remained normal. After cortical fibrosis occurred, a diversion of the blood flow from the cortex to the medulla was noted. Cortical atrophy following papillary loss is not secondary to microvasculature insufficiency, but is a consequence of obstruction of the collecting ducts. The physiologic changes which follow papillectomy are due to interruption of the loops of Henle and cortical scarring.

The renal collecting system after medullary damage.

The micromorphology of the renal collecting system after unilateral papillectomy in rabbits was investigated. Two weeks to six months after papillectomy, tubular micropuncture studies were performed. Cleared specimens were studied by light microscopy and microradiography. Histologic and physiologic correlations were made. At two to four weeks, the papillectomized kidneys were smaller and had smooth, mottled surfaces. At one to six months, there was cortical scarring with decreased concentrating ability. Ductal micropuncture revealed dilated collecting tubules and ducts which were obstructed at the papillectomy site. It is concluded that obstructed collecting ducts may be responsible for the cortical atrophy and are the primary cause of renal cortical damage after papillectomy in our model.

Microcirculation of the lymph node with metastases.

Microangiographic and histologic examination of the popliteal lymph node was performed on 49 rabbits 3 to 55 days after V2 tumor implantation into the hind paw. Control animals received subcutaneous tissue extract from normal rabbit donors. During the first 10 days after the tumor implant from an allogeneic animal donor, the draining lymph node exhibited a hypervascular response which after 2 weeks gradually subsided. Subsequently, during the early stages of lymph node metastasis there was still hypervascularity adjacent to the metastatic deposit. In about 4 weeks the metastases became more established and surrounded by layers of plasma cells. The hypervascular changes of the surrounding lymph node subsided by this time. In lymph node metastases the microvasculature could be an indicator of the immunologic activity of the host.

The lymph node in experimental xanthomatosis.

There is significant, progressive replacement of the lymphoid elements of the lymph node by foam cells in experimental xanthomatosis. These cells first form islands in the subcortical area. Subsequently they involve the medullary cords and finally, they replace the cortex. The xanthomata are higly vascular, consisting of a dense capillary network of samall and short capillaries. These newly visualized capillaries are fully integrated and incorporated in the normal blood supply of the lymph node. No significant distortion of the larger venules and arterioles were observed. It is noteworthy to observe the great capacity of the vascular supply of the lymph node in reacting to situations of significant enlargment and replacement of the lymphoid elements.

Blood microcirculation in the lymph node in xanthomatosis.

Twenty-five New Zealand white rabbits were placed on an atherogenic diet for 7 to 160 days to induce xanthomatosis. The microvascular morphology of the popliteal lymph node was studied throughout the development of xanthomatous replacement. The lymph nodes were serially sectioned and studied histologically and by microangiography. In animals which were on the atherogenic diet for over 90 days, foam cells replaced almost all of the lymphoid elements. Xanthomata appeared first as islands in the subcortical area and later spread to the medullary cords and the cortex. The xanthomata were highly vascular and contained a rich and dense capillary network of 5 to 7 mu vessels which were incorporated in the normal blood supply of the lymph node. The richness of capillary supply exceeds the hypervascularity observed during the immune response. The morphology of the capillaries raises the possibility of angiogenesis.

Blood microcirculation in the lymph node during the primary immune response.

Microangiography performed after total blood replacement with contrast material provided complete visualization of the vascular structures of the lymph node. Starting of the 2nd day, there is capillary redistribution throughout the cortex of the lymph node. The previously rather avascular nodules dissolve, and the cortical lymphoid tissue becomes uniformly vascular. Beginning on the 2nd day and reaching its peak on the 5th day, there is a significant increase in diameter and density of the subcapsular and medullary cord capillaries. 15 days after the antigenic stimulus, the appearance of the microvasculature returns to normal. The postcapillary venules (the microvascular structures which follow the capillaries) are widely distributed throughout. Histologically, only a fraction of these venules have a high endothelial lining (HE venules). Therefore, it is suggested that among the postcapillary venules, those with high endothelial lining should be specifically denoted. Great individual variation in the number of HE venules was observed, and no correlation with the timing of the immune response could be established. Whether the microvascular changes described lead to cellular change or are mere expressions of it cannot definitely be stated. However, the significant hypervascularity along the intranodal lymph pathways and the diffuse, even redistribution of the capillaries and postcapillary structures could greatly facilitate the humoral and cellular exchange between the circulating blood, the circulating lymph, and the tissues of the lymph node.