MULTIDETECOR CT AND EMBOLIC MESENTERIC ISCHEMIA: TAKE A LOOK AT THE HEART!

1. MULTIDETECOR CT AND EMBOLIC MESENTERIC ISCHEMIA: TAKE A LOOK AT THE HEART! I BEN YAACOUB, F SNENE, R KHARRAT, R BENNACEUR, H RAJHI, N MNIF Radiology department, Charles Nicolle hospital

2. Introduction • Mesentericischemia (MI) is a frequentclinical condition characterized by its clinical polymorphism. • It has an increasing prevalence because of eldering of the population. • 1% of emergency admission for acute abdomen . • It isassociatedwith a highmortality rate due to diagnosisdelay.

3. Introduction • MI isconsidered as a diagnosis and therapeuticemergengy. • The prognosisiscloselyrelated to the delaybetween the symptomsonset and the preoperative correct diagnosis. • Rapiddiagnosis the original cause and mechanism of MI is of greatconcern for the therapeutic issues.

4. Material & Methods • 10 patients • Meanage: 50 ans, sex ratio: 3/7. • History: • Cardiacrythmabnormalities (n=4) • Coagulopathy (n=3) • Atherosclerosis (n=6) • Clinicalfeatures: • Abdominal pain (n=10) withrapid (n=7) or progressive onset (n=3). • No relevant abnormalities on abdominal examination or blood tests (n=10).

5. Material & Methods • Abdominal CT wasperformed in all patients(MDCT GE 16) with: • Unenhanced CT • Enhanced CT (2ml/kg of iodinatecontrast media, 350mgI/ml, rate: 4ml/sec) • Arterial phase: performedwith bolus detection technique (smart prep) • Portal phase: 70 – 80 sec • 3D and Multiplanar reformations (MPR) wereperformed

6. Results VASCULAR SIGNS • Ostialfillingdefect of the superiormesentericartery (SMA) (n=2). • Fillingdefect of the main branch of the SMA (n=2). • No vascularfillingdefect (n=6)

7. Analyzing the filling of mesenteric vessels on transversal images demonstrated abrupt defect of SMA while superior vein is well enhanced

8. MPR allow better spatial assessment of vascular abnormalities. Thrombosis of the SMA without underlying vascular lesions (no evidence of atherosclerosis) is very suggestive of embolic MI.

9. Subocclusion of SMA 3D vascular reformation showedclearly the atherothrombosis of the SMA withheavy calcifications distally

10. On upper CT images involving the lower thoracic region, we saw an apical thrombus of the left ventricle. This finding was diagnostic for embolic MI Cardiac MRI performed in this 25-year-old women showed a transmural infarction in the LAD territory. CARDIAC EMBOLISM

11. SMA thrombosis associated with renal infarct PARADOXICAL EMBOLISM The upper thoracic images showed bilateral pulmonary embolism

12. Results DIGESTIVE SIGNS • Bowelinfarct (n=10) • Unehancement of bowelwall (n=8) • Thickening of bowelwall (n=2) • Pneumatosis (n=3) • Aeroportie (n=0)

13. Defect of enhancement of bowelwall Bowelwallthickening

14. Aeromesenterie: air withinarterialbranchs of SMA Pneumatosis Aeroportie

15. Discussion • Small bowel has terminalarterial vascularisation configuration • Obstruction of a branch or the main SMA resulats in arterial MI • Extension of bowelinfarctiscorrelated to situation of arterial occlusion: • Occlusion of the main SMA results in extensive MI withpoorprognosis • Occlusion of a distal branchresults in segmental MI thatcanbemanagedsurgically.

16. Discussion • Mortality and morbidity of arterial MI are veryhighalthoughprogress in diagnostic and therapeutic issues. • Earlydiagnosis of arterial MI iscritical and remain the unique chance to improve the prognosis • MDCT isnowrecognized to be an important tool for the diagnosis and must beperformedwithadapted technique for every MI clinical suspicion. • MDCT reliabilty has grown in the last few yearreaching 95% in 2009 ( 75% in 1996)

17. Discussion • Surgical management consist of resection of infarctedbowelthatshouldbeperformed as soon as possible in order to reducenecrosis extension. • Etiologic investigation of arterial MI is of greatconcernbecauseitmay change management of patients

18. Discussion • Mecanisms of arterial MI: • Arterialthrombosis: • Arterialembolism: • ATHEROSCLEROSIS +++ • Aged patients • Cardiovascular risk factors • (Hypertension, Diabetes, obesity…) • Evidence of multivascularinvolvment • (carotid, renalartery, coronaropathy,…) • EXTRA INTESTINAL THROMBOSIS MIGRATION • Younger patients • Cardiovascular risk factors =0 • Cardiacrythmdisorders • Atrial fibrillation +++ • Evidence of multivascularinvolvment • (carotid, renalartery, coronaropathy,…)

19. Discussion Besides the MI diagnosis MDCT mayofferprecious arguments for the etiologic investigation especially in differenciatingembolicversus thromboticmechanism.

20. Discussion

21. Discussion Origin of arterial MI embolism: • Cardiac thrombus • Paradoxicalembolism • Aorticthombus: due to • Aorticathrothrombosis • Chronic/acute aortic dissection

22. Discussion • Cardiac source of embolism • Myocardialinfarction (leftventricle+++) • Atrial fibrillation (left atrium+++) • Valvulardisease (Aorticstenosis) • Endocarditis(septicembolism) • Cardiactumors (myxoma +++)

23. Discussion • Paradoxicalembolism: • Definition: systemic arterial embolism requiring the passage of a venous thrombus into the arterial circulatory system through a right-to-left shunt. • Cause: intra cardiac communication: • Inter auricular communication • Aneurysm of the interauricularseptum • Patent foramen ovale (PFO)+++

24. Discussion • Paradoxicalembolism:can be presumed in the following criteria: • Deep venous thrombosis with or without pulmonary embolism. • Abnormal communication between right (venous) and left (systemic) circulation. • Clinical, angiographic, or pathologic evidence for systemic embolism. • Presence of a favourable pressure gradient, promoting right-to-left shunting.

25. Discussion • Aortic source of embolism: Are at higher risk of embolism: • Atherosclerotic aortic plaques > 4 mm • ulcerated plaques • plaques with mobile intra aortic components • hypodense and noncalcifiedplaques

26. Discussion • In ourseries, the cardiac source of MI embolismwasdetectedthanks to MDCT whileanalyzing the upper images of the abdominal acquisition. • One of thesetwo patient was a youngwomenwith no cardiovascularhistory. Further investigation were diagnostic for myocardialinfarction due to coronary malformation

27. Conclusion • Determination of MI mechanismis of greatconcern for therapeutic issues and patients outcome. • MDCT is the keyimaging technique for the diagnosis and prognosis of MI • Moreover, MDCT may help considering the mechanism of MI (embolism vs thrombosis) • Systematicanalysis of a technicallyreliable MDCT mayevenbe diagnostic for the origin of embolic MI.

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