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Magnetic resonance imaging findings and histopathological observations after percutaneous renal cryoablation in the
Qiang Zhu1, Tadashi Shimizu, Daisuke Abo
1Departments of Radiology and Pathology, Hokkaido University Graduate School of Medicine, Sapporo, Japan.
Purpose:
We investigated sequential changes in MRI and relevant histopathological findings after PRC.
Materials And Methods:
A total of 15 rabbits were examined with MRI and sacrificed immediately (3), and 7 (4), 45 (4) and 90 (4) days after PRC. MRI studies were reviewed for the signal intensity of cryolesions and correlated with pathological findings. MRI and pathological measurements of cryolesion sizes were compared using the paired t test.
Results:
CCN was produced in central areas of cryolesions and associated with hemorrhage, hemolysis, fibrous granulation and fibrosis that was orderly through days 1 to 90. Signal intensity was slightly hyperintense on T1-weighted spin-echo images immediately after PRC, and hyperintense on T1 and T2-weighted fast spin-echo images at 7 days. On T2-weighted fast spin-echo images there was a hypointense zone in peripheral areas between the central area and renal parenchyma at the prior 2 stages, which was consistent with PCN histologically. It was enhanced at 7 days. At 45 and 90 days the signal intensity of cryolesions was isointense or hypointense on the 2 sequences. Parenchymal injury adjacent to cryolesions was histologically recognized and visible as a hyperintense zone in 2 lesions at 45 days. This zone was enhanced in 2 lesions at 45 and 90 days. No statistical significance was apparent between the 2 measurements of cryolesions and CCN sizes (p <0.05).
Conclusions:
The MRI appearance of cryolesions reflects orderly histopathological findings. MRI distinguishes CCN from PCN, reveals injury to the renal parenchyma outside of cryolesions and accurately estimates the size of cryolesions and CCN.
Insights
Magnetic resonance imaging (MRI) of renal cryolesions in rabbits showed sequential changes that correlated with histopathology. MRI accurately assessed cryolesion size and distinguished central necrosis from peripheral injury.
Area of Science:
- Nephrology
- Radiology
- Pathology
Background:
- Percutaneous renal cryoablation (PRC) is a therapeutic procedure.
- Understanding the post-procedural changes is crucial for patient management.
- Sequential imaging and histopathological correlation is needed.
Purpose of the Study:
- To investigate sequential changes in MRI findings and histopathology after PRC in rabbits.
- To correlate MRI signal intensity and lesion size with pathological findings.
Main Methods:
- 15 rabbits underwent MRI at 0, 7, 45, and 90 days post-PRC.
- MRI signal intensity of cryolesions was analyzed.
- Histopathological examination was performed immediately and at 7, 45, and 90 days.
- MRI and pathological measurements were compared.
Main Results:
- Central coagulation necrosis (CCN) developed with orderly changes over 90 days.
- MRI signal intensity varied over time, reflecting hemorrhage, granulation, and fibrosis.
- Peripheral non-perfused zones (consistent with PCN) were identified and enhanced.
- Adjacent parenchymal injury was detected by MRI and confirmed histologically.
- No significant difference was found between MRI and pathological measurements of lesion size.
Conclusions:
- MRI findings of renal cryolesions correlate with sequential histopathological changes.
- MRI can differentiate central necrosis from peripheral injury.
- MRI accurately assesses cryolesion size and adjacent renal parenchyma injury.
