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Published on: October 20, 2013
Experimental pyelonephritis in piglets: diagnosis with MR imaging
D J Pennington1, G J Lonergan, C E Flack
1Department of Radiology, PSRD, Wilford Hall U.S. Air Force Medical Center, Lackland Air Force Base, TX 78236-5300, USA.
Purpose:
To compare findings at magnetic resonance (MR) imaging with those at histopathologic examination in the detection of experimentally induced pyelonephritis in piglets.
Materials And Methods:
MR imaging was performed in 23 piglets with and nine piglets without experimentally induced pyelonephritis. Escherichia coli were injected into the bladder of the 23 piglets with surgically created vesicoureteral reflux. Imaging was performed with unenhanced and contrast material-enhanced T1-weighted and fast multiplanar inversion-recovery (IR) and fast spinecho T2-weighted sequences. MR images and pathologic findings were reviewed independently by two pediatric radiologists and a pathologist, respectively, in a blinded fashion.
Results:
Sixty-four kidneys and 192 renal zones were evaluated. Coronal gadolinium-enhanced fast multiplanar IR imaging was the only sequence that was sensitive and specific for the diagnosis of pyelonephritis. For the two reviewers, respectively, sensitivity was 85% (n = 75) and 92% (n = 81) of 88 histopathologically positive zones and specificity was 95% (n = 99) and 94% (n = 98) of 104 pathologically negative zones. Findings at gadolinium-enhanced fast multiplanar IR imaging were not statistically different from findings at histopathologic examination in the detection of pyelonephritis. Interobserver reproducibility for the contrast-enhanced fast multiplanar IR sequence was excellent (kappa statistic = 0.82 and 0.90, respectively, for interpretation of a renal zone and of a kidney).
Conclusion:
Contrast-enhanced fast multiplanar IR imaging is a sensitive and specific test for detection of experimental pyelonephritis in this piglet model.
Insights
Contrast-enhanced fast multiplanar inversion-recovery (IR) magnetic resonance (MR) imaging accurately detects experimental pyelonephritis in piglets. This sensitive and specific MR technique shows findings comparable to histopathologic examination.
Area of Science:
- Veterinary Radiology
- Medical Imaging
- Nephrology
Background:
- Pyelonephritis, a kidney infection, is challenging to diagnose non-invasively.
- Experimental models are crucial for evaluating diagnostic techniques.
Purpose of the Study:
- To compare magnetic resonance (MR) imaging findings with histopathologic examination for detecting experimentally induced pyelonephritis in piglets.
- To assess the diagnostic accuracy of various MR imaging sequences.
Main Methods:
- MR imaging was performed on piglets with and without experimentally induced pyelonephritis.
- Contrast-enhanced T1-weighted and fast multiplanar inversion-recovery (IR) sequences were utilized.
- MR images were independently reviewed by pediatric radiologists and compared with histopathologic findings.
Main Results:
- Coronal gadolinium-enhanced fast multiplanar IR imaging demonstrated high sensitivity (85-92%) and specificity (94-95%) for pyelonephritis detection.
- MR imaging findings were not statistically different from histopathologic results.
- Excellent interobserver reproducibility was achieved for the contrast-enhanced IR sequence.
Conclusions:
- Contrast-enhanced fast multiplanar IR imaging is a sensitive and specific diagnostic tool for experimental pyelonephritis in piglets.
- This MR technique shows promise for non-invasive diagnosis of kidney infections.
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