Diffusion–Weighted Imaging and Apparent Diffusion Coefficient Values Versus Contrast–Enhanced MR Imaging in the Identification and Characterisation of Acute Pyelonephritis
To compare contrast-enhanced (CEMR) and diffusion-weighted (DWI) magnetic resonance imaging in diagnosing acute pyelonephritis (APN) and to assess ADC measurement reliability in differentiating among normal renal parenchyma, APN and abscesses.
Eighty-eight patients (80 women, mean age 36.5 years) with clinical suspicion of APN were retrospectively reviewed. An experienced observer quantified lesions with a score ranging from 0 to 3. DWI and CEMR were compared on the basis of the assigned score, total examination number (88) and on presence (36)/absence (52) of abscesses. ADC values, calculated at the healthy parenchyma, APN and abscessed were compared to each other.
Agreement between CEMR and DWI was 94.3 % (83/88 patients; P < 0.05). In the APN group, DWI was awarded the highest visibility score compared to CEMR (P = 0.05), while in the abscess group CEMR had the highest score (P = 0.04). The difference between ADC values of the APN-healthy parenchyma and abscess-APN groups was significant (P < 0.05). The area under the ROC curve of ADC values of the APN-healthy and abscess-APN groups were found to be 0.94 (95 % CI; cutoff value = 2) and 0.78 (95 % CI; cutoff value = 1.2) respectively.
Diffusion-weighted imaging appears reliable in the diagnosis and follow-up of acute pyelonephritis and could provide a reasonable alternative to contrast-enhanced magnetic resonance imaging.
• Acute pyelonephritis (APN) is an inflammatory process that preferentially affects young women
• Contrast-enhanced MRI is the reference investigation for the diagnosis and follow-up of APN
• Diffusion-weighted imaging can help differentiate between APN and abscesses
• This is especially useful when administration of contrast agent is contraindicated.
Keywords:Acute pyelonephritis Dynamic contrast-enhanced magnetic resonance diffusion-weighted imaging apparent diffusion coefficient DWI ADC DCEMR
- 28.De Keyzer F, Thoeny HC (2011) Diffusion-weighted imaging of diffuse renal disease and kidney transplant. In: Taouli B (ed) Extracranial applications of diffusion-weighted MRI. Cambridge University Press, Cambridge, pp 32–45Google Scholar