Related Experiment Videos
A comprehensive approach using MR imaging to diagnose acute segmental mesenteric ischemia in a porcine model
1Department of Radiology, Stanford University Medical Center, CA 94305-5105, USA.
Objective:
Acute mesenteric ischemia is a lethal disease that lacks a noninvasive diagnostic test. We evaluated the abilities of contrast-enhanced MR angiography, MR oximetry, and real-time interactive MR imaging to diagnose segmental mesenteric ischemia in a porcine model.
Materials And Methods:
Segmental mesenteric ischemia was created by subselective Gelfoam embolization of the mesenteric circulation in eight pigs. Conventional digital subtraction angiography (DSA), MR oximetry, and real-time interactive MR imaging of the small bowel were performed before and after embolization. Changes in the perfusion pattern seen on DSA established the regions of true ischemia. Postembolization DSA and MR angiography were compared with this gold standard.
Results:
Both MR angiography and DSA had high sensitivity (91% and 100%, respectively) for detecting ischemic regions. The difference was not statistically significant (p > .2). MR angiography yielded lower specificity than DSA (80% and 90%, respectively; p < .01). After embolization, the oxygen saturation in the superior mesenteric vein (SMV) dropped significantly (p < .005). After embolization, the SMV also showed oxygen saturation significantly lower than that in the inferior vena cava (p < .005). In two of the animals, segmental hypomotility of the small bowel was observed.
Conclusion:
MR oximetry is capable of detecting oxygen desaturation caused by segmental ischemia. A loss of oxygen saturation in the SMV relative to that in the inferior vena cava provides a convenient marker of mesenteric ischemia. Contrast-enhanced MR angiography has sensitivity and specificity approaching those of DSA. Both MR techniques hold promise for the detection of acute mesenteric ischemia.
Insights
Magnetic resonance (MR) oximetry and MR angiography show promise for diagnosing acute mesenteric ischemia, a condition lacking noninvasive tests. MR oximetry detects oxygen desaturation, while MR angiography approaches digital subtraction angiography in accuracy.
Area of Science:
- Medical imaging
- Gastroenterology
- Vascular surgery
Background:
- Acute mesenteric ischemia is a critical condition with high mortality.
- Current diagnostic methods for mesenteric ischemia are invasive or lack sufficient accuracy.
- Noninvasive diagnostic tools are urgently needed for early detection and intervention.
Purpose of the Study:
- To evaluate the diagnostic capabilities of contrast-enhanced MR angiography, MR oximetry, and real-time interactive MR imaging for segmental mesenteric ischemia.
- To compare the efficacy of these MR techniques against conventional digital subtraction angiography (DSA) in a porcine model.
Main Methods:
- Segmental mesenteric ischemia was induced in pigs via embolization.
- MR angiography, MR oximetry, and real-time interactive MR imaging were performed before and after ischemia induction.
- DSA was used to establish the gold standard for ischemic regions, with subsequent comparison to MR techniques.
Main Results:
- MR angiography demonstrated high sensitivity (91%) for detecting ischemia, comparable to DSA (100%).
- MR angiography showed lower specificity (80%) than DSA (90%).
- MR oximetry revealed significant oxygen desaturation in the superior mesenteric vein (SMV) post-embolization, serving as a key indicator.
Conclusions:
- MR oximetry effectively detects oxygen desaturation indicative of mesenteric ischemia.
- A drop in SMV oxygen saturation relative to the inferior vena cava is a reliable marker for mesenteric ischemia.
- Contrast-enhanced MR angiography offers diagnostic performance close to DSA, highlighting the potential of MR techniques for acute mesenteric ischemia detection.