Keywords:
Kidney, Abdomen, Contrast agents, CT, Contrast agent-intravenous, Calcifications / Calculi
Authors:
A. M. C. Odenrick, N. Kartalis, N. Voulgarakis, F. Morsbach, L. Loizou; Stockholm/SE
DOI:
10.1594/ecr2018/C-1535
Methods and materials
For this retrospective study institutional review board approval was obtained.
Study population:
Fifty consecutive patients undergoing MDCT of the kidneys according to our department’s fourth-phase standard protocol and having in the non-contrast phase (NCP) at least one kidney stone were included in the study.
We excluded cases: (1) where the calculus was located in the wall of a vessel or a cyst,
(2) where,
due to technical reasons,
the contrast enhancement of the renal cortex was poor,
(3) where the dose of intravenous injected contrast media was lower than the standard dose (<0,5g I per kilo body-weight) due to renal dysfunction,
(4) where medullary nephrocalcinosis was suspected and (5) where the stones were located in the ureter.
Image acquisition:
All examinations were performed in the radiology department at Karolinska University Hospital on a 64-MDCT scanner. All the patients had been examined according to our department’s four-phase protocol with a NCP,
a CMP,
a NGP and excretory phase (EP).
Imaging assessment:
Two radiologists in consensus evaluated the NCP from each examination and reported the number,
location and size of stones.
Three abdominal radiologists,
blinded to the findings of the NCP,
reviewed independently the contrast-enhanced phases (CEP) on two occasions with a minimum time interval of one week.
They scored the number of stones in each kidney and reported the location.
The reviewers had access to axial,
coronal and sagittal 5mm thick reformations for each case.
For the inter-observer agreement,
the intraclass correlation coefficient (ICC) was calculated [11].
The detection rate of renal stones was calculated for each radiologist and compared between the two CEP´s and the results were analysed with regard to the size of the stones.
The correlation between the detection rate and the size of the stones divided into three different subgroups,
namely,
less than or equal to 2mm,
3-5mm and larger than or equal to 6mm was analysed.