Abstract:
Background. Urinary infections are common, especially in women (50–60% will have at
least one episode in life). Acute pyelonephritis is severe and can cause abscess, infarction, or
sepsis, with significant risks for kidney health. Interstitial nephritis causes 15–20% of AKI
cases. Early diagnosis is essential.
Objective(s). The study compares the effectiveness of ultrasound, CT, and MRI in diagnosing
pyelonephritis and interstitial nephritis, highlighting the sensitivity and clinical applicability
of each method.
Materials and methods. This paper analyzes 7 clinical studies from 2009–2023, including
814 patients with acute and chronic pyelonephritis, and interstitial nephritis. Imaging
methods evaluated were ultrasound, CEUS, CT, and MRI, focusing on their sensitivity,
specificity, and applicability in detecting complex and significant renal inflammatory lesions.
Results. Acute pyelonephritis: B-mode ultrasound has modest sensitivity (50–75%) and
moderate specificity. Doppler increases sensitivity up to ~89%, but specificity is low. CEUS
offers 95–98% sensitivity and 100% specificity. Contrast-enhanced CT is the gold standard
for complicated APN (80–90%), detecting complications. MRI has similar sensitivities to CT
(~89%) but is clinically limited. Chronic pyelonephritis: CT reveals scars and atrophy; MRI
shows lesions without radiation. Ultrasound shows small, irregular kidneys but not scars.
Acute interstitial nephritis: Imaging diagnosis is difficult. Biopsy remains the gold standard.
Conclusion(s). Each imaging method has advantages and limitations in assessing renal
inflammation. Ultrasound is accessible and radiation-free, recommended first, but has
limited detection of subtle lesions. CT and MRI are sensitive, but CT involves radiation. CEUS
is accurate for focal lesions.
