MR Diffusion
Claim CME CreditPOINT OF CARE INFORMATION
This CME activity consists of the student reviewing the video of the professor reviewing the case as well as the associated DICOM image set related to the case in question.
Learning Objectives
As a result of participation in this activity, participants should be able to:
- Provide improved patient care.
- Greater knowledge of the imaging characteristics of the patient's disease.
- Understand a better approach to interpretation of studies.
Faculty Disclosure
Mehmet Albayram, MD, Ivan Davis, MD, Mariam Hanna, MD, Anthony Mancuso, MD, Ronald Quisling, MD, Dhanashree Rajderkar, MD, Priya Sharma, MD, Roberta Slater, MD and Joann Stamm, MBA have disclosed that they have no relevant financial relationships. No one else is a position to control content have any financial relationship to disclose.
CME Advisory Committee Disclosure:
Conflict of interest information for the CME Advisory Committee members can be found on the following website: https://cme.ufl.edu/disclosure/.
Continuing Medical Education Credit
Accreditation: The University of Florida College of Medicine is accredited by the Accreditation Council for Continuing Medical Education (ACCME) to provide continuing medical education for physicians.
Credit: The University of Florida College of Medicine designates this enduring material for a maximum of 0.5 AMA PRA Category 1 Credits. Physicians should claim only the credit commensurate with the extent of their participation in the activity.
CA0378-MR Diffusion
View Images
CA0378-MR Diffusion
Case ReportHistory
Exam
Prior Study
There is focal hyperdensity in the distal basilar apex consistent with acute thrombus.
There is no discernable cytogenic edema, and certainly no obvious edema to confirm stroke outside the treatment window.
CT Perfusion
CT perfusion demonstrates minimal prolonged TTP in all structures in the posterior fossa and in the occipital polar areas compared to the cerebrum. MTT is prolonged in same areas. There is focal prolonged TTP in the caudal Rt. cerebellum with diminished CBF & CBV consistent with more chronic ischemic change (likely prior ischemic event).
Included post contrast head CT does demonstrate opacification of the proximal afferent arteries and all but the apex of the basilar artery. PCA’s fill retrograde from circle of Willis accounting for the delayed TTP and prolonged MTT in both occipital poles.
CTA of the Neck
There is a focal stenosis of the left vertebral artery origin. The stenosis measures >60%, however, there is no post stenotic dilatation nor distal vessel collapse. There is no apparent ulceration. But with evidence of multicentric embolic type strokes, this stenosis is likely source.
CTA of the Head
As observed on the CT perfusion included post contrast head CT, the proximal posterior fossa afferent circulation is patent. However, there is thrombus in the distal basilar artery segment including its’apex. Retrograde collateral is derived from the circle of Willis although through small P-com’s. This accounts for the delayed PCA filling on CT perfusion. The thrombus measure approximately 3-4 mm’s in length; both PICA & AICA vessels are patent. The SCA arteries & branches demonstrate only trace filling.
There is a wide zone of limited artery opacification between the inferior vermian artery and the unoppacified super vermian artery (‘wide collateral gap). However, this is only based on the initial contrast injection.
Inferior vermian veins are evident but not the superior cerebellar or superior vermian venous system.
Post contrast head CT for Venocapillary Pool analysis
At least some of the superior vermic vessel appear on the delayed scan. These vessels plus the relatively normal parenchymal density are consistent with reasonable collateral to the SCA and superior vermic arterial territories.
No apparent CT density drop out is evident on the initial or delayed post contrast CT head.
All veins are NL for cerebrum, thalamus and cerebellum.
Findings
MR diffusion
Multicentric, small, areas of post ischemic diffusion restriction (positive on DWI & ADC) within both cerebellar hemispheres (distal PICA branches) within the Rt. occipital polar regions (distal P4 branches), and within the Rt. mesial thalamus. The Rt. thalamus has two separate infarcts; one is from involvement of Rt. basilar tip perforators to the mesial ventral thalamus and the second is from the dorsal thalamic perforators arising from the Rt. posterior mesial choroidal artery (which itself arises off the Rt. P2 PCA segment).
There is a more subtle ischemic event in the right cerebral peduncle likely from a distal segment basilar perforator.
These embolic infarcts are not likely of the same age based on the ADC maps. The most acute are those involving the mesial Rt. thalamus and the Rt.occipital polar area. The pattern of multicentric relatively small infarcts in distal arterial perfusion indicates a thromboembolic process. The source of the emboli is indeterminate.
