Answer for CoW 20 November 2016
ACUTE LT ACA INFARCT AND RT MCA OCCLUSION
Findings
Acute left anterior cerebral artery territory infarcts noted in the left parasagittal frontal region and involving the genu of corpus callosum (left side). Few adjoining acute lacunar infarcts also noted. Chronic infarcts noted in the right ganglio-capsular and the left periventricular occipital regions. 3D ASL perfusion imaging revealed relatively decreased cerebral blood flow in the above region. Decreased cerebral blood flow also noted in right fronto-temporal regions . MR Angiogram The left A2 segment is not visualised – consistent with occlusion. The right middle cerebral artery is occluded.
Discussion
ASL (Arterial Spin Labelling ) is a NON INASIVE MR perfusion method for quantitatively measuring cerebral blood flow (CBF) There are three types of ASL 1.PULSED ASL - SINGLE SHOT DURATION PULSE (PASL) - higher and stable tagging efficiency with respect to flow velocity magnetization of blood is labeled (inverted) in large volume(slab) with short RF pulse 2.EXTENDED ASL - CONTINUOUS ASL (CASL) - CASL provides the largest ASL signal change , greatest SNR and can be advantageous . continuous labelling of the blood water during its passage through a label plane Labeling is typically performed continuously for 1 to 2 seconds, after which a postlabeling delay is inserted before imaging. This delay allows the labeled blood to reach the region of interest in the brain and lets it clear from the feeding arteries. 3.PULSED CONTINUOUS OR PSEUDO CONTINUOUS ASL p CASL uses a longer tagging bolus. many shortduration RF pulses can be used to effectively labeL Arterial water over a longer duration. ASL Perfusion detects decreased CBF in infarcted regions . This case is to highlight the value of ASL to show decreased CBF even in regions , even before infarct is evident in DWI . Decreased CBF is noted in the right middle cerebral artery territory , with MCA occlusion even before abnormality is picked up in DWI.
Findings
Acute left anterior cerebral artery territory infarcts noted in the left parasagittal frontal region and involving the genu of corpus callosum (left side). Few adjoining acute lacunar infarcts also noted. Chronic infarcts noted in the right ganglio-capsular and the left periventricular occipital regions. 3D ASL perfusion imaging revealed relatively decreased cerebral blood flow in the above region. Decreased cerebral blood flow also noted in right fronto-temporal regions . MR Angiogram The left A2 segment is not visualised – consistent with occlusion. The right middle cerebral artery is occluded.
Discussion
ASL (Arterial Spin Labelling ) is a NON INASIVE MR perfusion method for quantitatively measuring cerebral blood flow (CBF) There are three types of ASL 1.PULSED ASL - SINGLE SHOT DURATION PULSE (PASL) - higher and stable tagging efficiency with respect to flow velocity magnetization of blood is labeled (inverted) in large volume(slab) with short RF pulse 2.EXTENDED ASL - CONTINUOUS ASL (CASL) - CASL provides the largest ASL signal change , greatest SNR and can be advantageous . continuous labelling of the blood water during its passage through a label plane Labeling is typically performed continuously for 1 to 2 seconds, after which a postlabeling delay is inserted before imaging. This delay allows the labeled blood to reach the region of interest in the brain and lets it clear from the feeding arteries. 3.PULSED CONTINUOUS OR PSEUDO CONTINUOUS ASL p CASL uses a longer tagging bolus. many shortduration RF pulses can be used to effectively labeL Arterial water over a longer duration. ASL Perfusion detects decreased CBF in infarcted regions . This case is to highlight the value of ASL to show decreased CBF even in regions , even before infarct is evident in DWI . Decreased CBF is noted in the right middle cerebral artery territory , with MCA occlusion even before abnormality is picked up in DWI.
Note:
We do not discourage differential diagnosis. But all the differentials must satisfy the findings noted in the case.
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Did you Know?
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We do not discourage differential diagnosis. But all the differentials must satisfy the findings noted in the case.
If you feel you have answered rightly but cannot find your name in the above list, please call 09551942599.
Did you Know?
The order in which the names appear in this winner's list is based on the time of submission. The first person to send the correct answer gets his/her name on top of the list!