Diagnostic Efficacy of Magnetic Resonance Imaging versus Computed Tomography in Characterisation of Renal Infections

Abstract

Introduction: Urinary Tract Infections (UTI) are one of the most frequently diagnosed infections worldwide, accounting for patient morbidity at any age group. It can affect both the upper and lower urinary tract. Over the past decade, a variety of Magnetic Resonance Imaging (MRI) methods have been developed and applied to many renal diseases. Current advances in MRI techniques have enabled the non-invasive investigation of renal disease. Aim: To evaluate the efficacy of MRI in diagnosing renal infections and compare the diagnostic performance and accuracy of MRI with Contrast Enhanced Computed Tomography (CECT) in characterising renal infections. Materials and Methods: It was a hospital based crosssectional study, conducted on total 30 patients (age group 20- 70 years, 6 males and 24 females) who came to the Department of Radiology of the institute from January 2019 to October 2019, with clinical suspicion of renal infections and showed positive radiological findings in CECT that were suggestive of renal infections. Magnetic Resonance- Kidney Urinary Bladder (MR-KUB) region was performed for all the patients by 128 slice CT scanner and 1.5 Tesla MRI scanners. Special sequences like Diffusion Weighted Imaging (DWI) MRI were employed and images acquired were analysed radiographically and were reviewed to compare their ability to find various UTIs. The collected data were analysed using Statistical Package for Social Sciences (SPSS) version 23.0. Descriptive statistics frequency and percentage and mean±SD was used for analysis of the collected data. Sensitivity, specificity, Positive Predictive Value (PPV) and Negative Predictive Value (NPV) were calculated to compare the tools. Results: The current study comprised of 30 patients with male to female ratio 1:4 and 46.66% patients from 41-50 years age group. MRI along with DWI showed sensitivity of 88.46% in detecting intrinsic parenchymal signal changes, and sensitivity of 100% in detecting abscess formation, intra/extra parenchymal, perinephric fluid collections, micro-abscesses, large foci of air and obstructive calculi, whereas it was less sensitive in detecting non-obstructive calculi and tiny air foci. Non-Contrast CT (NCCT) was able to diagnose renal infection in 12 out of 30 patients with sensitivity of 40%. Conventional MRI diagnosed renal infection in 21 of these 30 patients with sensitivity of 70%, DWI was able to show the changes in 27 patients with sensitivity of 90% in comparison to the cases prediagnosed with CECT. Conclusion: MRI has higher sensitivity than non-contrast enhanced CT for detection of renal infections. DW MRI is equally sensitive in detecting renal infections, compared to contrast enhanced CT, and is more sensitive compared to conventional MR imaging. DWI can also be used to differentiate pyonephrosis from hydronephrosis and in early detection of micro-abscesses.

Keywords

• contrast enhanced computed tomography
• diffusion weighted imaging
• radiological findings
• urinary tract infections.