Observer variation in assessing renal scarring

Radiologic evaluation of urolithiasis

Interobserver variations between three radiologists with different backgrounds (duration of practice, and departments) were studied in connection with the diagnosing of urolithiasis. Films from 152 consecutive patients (examined with conventional abdominal films, urography/tomography) were analyzed independently. With respect to the number of patients with or without calculi there was agreement between the three observers in 129 of the 152 cases, which was taken to represent very good agreement beyond chance. The total number of stones was interpreted as 832, 460 and 570 respectively, and the median stone size as 6, 9 and 11 mm2. There was a fair interobserver agreement rate regarding whether stones were localized to the renal parenchyma or calyces, and whether stenosis/stricture or hydronephrosis was present. Tomography appeared to reduce the interobserver variability significantly. Adequate bowel cleaning, oblique projections, and lack of clinical information apparently did not influence the agreement rate. It was concluded that such interobserver variations are factors of importance in the reliability of the radiologic evaluation of urolithiasis.

Urographic findings in adults with chronic pyelonephritis

The radiological findings in a cohort of 138 adults with chronic pyelonephritis are presented and the following conclusions made. Scarring is commoner in the right kidney than the left and is found in the upper, middle and lower poles with decreasing frequency from above down. Agreement between observers in the grading of scarring in urograms taken without standardisation or routine tomography, is sufficiently high to justify the continued use of the intravenous urogram as a screening test but is not high enough to detect any progression of scars in the group over a 6.5-year period. Repetition of urograms seldom reveals the development of calculi or other new abnormalities and is not justified as a clinical routine. The combination of extensive bilateral renal scarring and proteinuria is associated with the worst renal function.

Upper urinary tract changes in patients with spinal cord injury

Two hundred and six intravenous urograms on 119 patients with spinal cord injury were reviewed and the findings correlated with the clinical data. Fifty (42%) of 119 patients had pathological changes in their upper urinary tracts. The most common feature was impaired renal emptying. Patients with normal and pathological upper tracts had similar findings according to the number of positive urine cultures during the first post-injury year, but in the follow-up those with pathological urograms showed bacteriuria significantly more often. Febrile urinary tract infections at least once a year were encountered in the follow-up of 40% of the patients with pathological urograms, as compared with 8% with normal urograms. All patients with severe renal changes had impaired emptying from the kidneys. This supports the view that the basic patho-physiological mechanism leading to upper tract deterioration in patients with spinal cord injury is a functional or mechanical obstruction of the lower urinary tract. This should be treated actively before irreversible renal changes develop.