A critical appraisal of the radiological evaluation of nephrocalcinosis.
OBJECTIVE
The level of agreement concerning the diagnosis of nephrocalcinosis (NC) based on ultrasonography (US), computed tomography (CT) or kidney/ureter/bladder (KUB) X-ray was assessed.


METHODS
Sequences of KUB+US+CT from 62 patients, 48 with at least one exam suggesting NC and 14 with pelvicalyceal calcifications (nephrolithiasis) were reviewed twice by 3 radiologists (firstly randomized and secondly presenting KUB+US+CT of each patient together).


RESULTS
The intraobserver concordance varied from 76 to 90% for KUB, 77 to 85% for US and 82 to 89% for CT. There was a significant change in diagnosis between the 1st and 2nd reviews for observer 1 in KUB and CT, for observer 2 in US, but not for observer 3. Evaluating patients' exams together did not provide a better agreement. The highest sensitivity and specificity (92 and 89%, respectively) were only attained when 2 exams suggested NC diagnosis, being CT one of them. These enabled us to suggest that 33 out of 48 (62.5%) patients had NC (evidenced in US+CT+KUB (81.8%), US+CT (12.1%) or KUB+CT (6.1%).


CONCLUSIONS
The low level of concordance renders the radiological diagnosis of NC difficult. Nephrocalcinosis should be confirmed by CT combined with either US or KUB.
Cheidde
Lara
L
Nephrology Division, Universidade Federal de São Paulo (UNIFESP), São Paulo, Brazil.
Ajzen
Sérgio Aron
SA
Tamer Langen
Cecilia Helena
CH
Christophalo
Dejaldo
D
Heilberg
Ita Pfeferman
IP
D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D008297:Male; D008659:Metabolic Diseases / Q000175:diagnosis / Q000209:etiology; D008875:Middle Aged; D009397:Nephrocalcinosis / Q000150:complications / Q000000981:diagnostic imaging*; D015588:Observer Variation; D011859:Radiography; D012680:Sensitivity and Specificity; D014463:Ultrasonography