The Diagnostic Value of Magnetic Resonance Urography Using A Balanced Turbo Field Echo Sequence

Abstract

The aim of the study was to compare the inter-observer variability and the accuracy of magnetic resonance urography (MRU) using a thin sectional balanced-turbo field echo (B-TFE) sequence for detecting ureteral calculi and to determine the effect of additional factors (size, density and location of the calculus) on the sensitivity and specificity of the MRU.

MRU and CT images were evaluated independently by two radiologists according to presence, density and localization of calculi. The degrees of inter-rater agreement for categorical items were evaluated by the Kappa coefficient.

According to the 1st and 2nd observers, the sensitivity of MRU was 65.9 %, 71.8 % and the specificity of MRU was 95.9 %, 100 %, respectively. Inter-observer agreement was 84.6 % for stone detection. The larger size had a better effect on detectability (p < 0.05). Also, the higher density had a better impact on detectability (p < 0.05).

Our study has shown that B-TFE MRU was useful to detect ureteral calculi. However, B-TFE MRU has low sensitivity and high specificity in comparison with CT images. MRU is a reasonable alternative imaging technique for follow-up periods of selective groups like patients with large urinary stones, children or pregnant patients when ionizing radiation is undesirable.

aEuro cent According to 1st and 2nd observers, sensitivity of MRU was 65.9 %, 71.8 %, respectively.

aEuro cent According to 1st and 2nd observers, MRU specificity was 95.9 %, 100 %, respectively.

aEuro cent Interobserver agreement was found to be over 84 % for stone detection.

aEuro cent B-TFE sequence provides calculus follow-up without radiation.

aEuro cent Larger calculi and more dense calculi individually have the better effect on detectability.