14. Mesenteric ischemia is condition
characterized by inadequate blood flow to
or from the involved mesenteric vessels
supplying a particular segment of bowel
15. PATHOPHYSIOLOGY :
ISCHEMIC INJURY DEPRIVES O2 AND NUTRITION TO
CELLULAR METABOLISM AND ITS INTACTNESS
↓
DUE TO DECREASED ARTERIAL PRESSURE DISTAL
OBSTUCTION COLLATERALS FORMED
↓
AFTER CRITICAL PERIOD,PERSISTANCE OF ISCHEMIA
VASOCONSTRICTION ↓
INCREASED ARTERIAL PRESSURE WHICH HAMPERS
COLLATERALS
16. ARTERIAL OCLUSION VENOUS OCLUSION
VASOSPASM AND SUBSEQUENT STASIS AND EDEMA
LOSS OF CELLULAR INTEGRITY
↓ ↓
INTESTINAL NECROSIS AND PERITONITIS
17. ACUTE BOWEL ISCHEMIA STAGES
STAGE I – REVERSIBLE
LIMITED TO MUCOSA ONLY
STAGE II – EXTENDS SUBMUCOSA AND
MUSCULARIS MUCOSA
STAGE III – TRANSMURAL (HIGH MORTALITY)
24. ABDOMINAL PLAIN
RADIOGRAPH
Gas filled, dilated small bowel loops with air fluid
levels.
Thumb printing sign (thickening of bowel wall +
valvulae (edema)
Pneumatosis intestinalis.
Mesenteric + portal vein gas
25.
26.
27.
28. Ultrasound and Doppler
In patients suspected of acute mesenteric
ischemia do not typically present to vascular
ultrasound due to severity of their symptoms
and urgency of condition.
It has important role in chronic mesenteric
ischemia
29. Indirect evidence
Rarely identification of occlusion of SMA / SMV.
Dilated bowel loops and bowel wall thickening
Pneumatosis intestinalis
Air in portal venous system
34. It is a noninvasive means with proven value in
detecting mesenteric artery stenosis and
occlusion.
35. USG & Doppler Findings
Grey scale evaluation :
- atherosclerotic plaque or thrombus at the site of stenosis /
occlusion.
Color Doppler :
Luminal narrowing
Color flow aliasing
Reversal of flow
Collateral vessels
36. Normal wave form patterns
High resistance flow with low diastolic velocities
in fasting state characterize SMA & IMA.
Low resistance flow with high end diastolic
velocities characterize celiac artery.
37.
38. Normal velocities
Range of normal blood flow velocities in
Celiac artery : 98 – 105 cm/sec
SMA : 97 – 142 cm/sec
IMA : 93 -189 cm/sec
Widely accepted criteria are based on the
PSV measurements of mesenteric arteries
39. Pulsed Doppler :
Elevated velocities
PSV of > 200 cm/sec in celiac artery
PSV of > 275 cm/sec in SMA are predictive of
stenosis of 70% or more.
Mesenteric : Aortic ratio greater than 3 is
associated with hemodynamically significant
stenosis .
43. CT is the primary imaging modality, and it
has been proven to be highly accurate in
the diagnosis of mesenteric ischemia
Sometimes depict the underlying etiology
44. MDCT is useful in patients with suspected ischemia
because it can :-
help detect ischemic changes in the affected small
bowel loops and mesentery and
help determine the cause of the ischemia by allowing
evaluation of the mesenteric vasculature.
45. • MPR
• CT angiograms
• MIP
• VR
• TTP
• Arterial: 35-40 s
• Venous:60 s
46. CT Scan Findings In Mesenteric
Ischemia
Specific CT signs
Thromboembolism in the mesenteric
vessels
Lack of bowel enhancement
48. Signs of bowel gangrene:
Large amount of intraperitoneal fluid
Gas in the mesenteric / portal vessels
Intramural gas
Thinned bowel wall with poor or absent
enhancement
75. COLONIC ISCHEMIA:
MOST COMMON FORM OF INTESTINAL
ISCHEMIA
COMMON IN 7TH DECADE
MOST COMMON NONOCLUSIVE
CAUSES LIKE HYPOTENSION STATUS
,VASCULITIS AND OTHER
VASCULOPATHIES
CLINICAL FEATURE:
ABDOMINAL PAIN ,BLOODY DIARRHOEA,
76.
77.
78.
79. Chronic M I
Etiology
Atherosclerosis
Extrinsic compression
Vasculitis
Fibromuscular dysplasia
80. Abdominal Angina
Intermittent mesenteric ischemia in severe arterial
stenosis with inadequate collateralization
provoked by food ingestion.
Postprandial abdominal pain (due to "gastric steal"
diverting blood flow away from intestine) .
Fear of eating large meals .
Weight loss.
Malabsorption
81. Diagnosis of intestinal angina is justified
only if …
At least two of the major mesenteric arteries
are shown to be occluded
and
Third artery is narrowed by atheroma.
CMI-Diagnosis by exclusion
82.
83. Computed tomography
Used to for
-screening the patients with suspected
chronic mesenteric ischemia
-Calcified plaque.
-collateral vessels.
87. It is the gold standard for
diagnosis of mesenteric vascular
occlusion.
88.
89.
90. 63-year-old woman status post aortic valve replacement who presents with a one
week history of abdominal pain becoming quite severe over the last 24 hours.
91.
92. Role of interventional radiology
NOMI-
selective catheter-directed administration of
vasodilating agents
Catheter directed thrombolysis
Percutaneous transluminal angioplasty
Fenestration of the aortic dissection.
93. Post OP - Diffuse vasospasm
without occlusions.
Post Papaverine infusion
Arteriogram 24 hr later.
Reversal of vasospasm.
99. Current role of MRI is yet to be defined.
True FISP images is used to assess large
mesenteric vessel occlusion
MRI has significant problem in detecting
small thromboemboli in peripheral vessels
Routine use of MRI patients with suspected
mesenteric arterial occlusion may not be
justified
100. Sagittal subvolume and coronal subvolume MIP images show severe stenosis of
the celiac, superior mesenteric and inferior mesenteric arteries.