CASE 651 Published on 22.03.2001

Evaluation of acute infarct and leukoariosis with diffusion MRI

Section

Neuroradiology

Case Type

Clinical Cases

Authors

R. N. Sener

Patient

72 years, male

Categories
No Area of Interest ; Imaging Technique MR-Functional imaging
Clinical History
Right-sided weakness, hemisensory loss, and homonymous hemianopia
Imaging Findings
The patient presented with a transient ischemic attack. Six days later he developed right-sided weakness, hemisensory loss, and homonymous hemianopia. Echo-planar diffusion MRI was performed using the 'trace' technique (TR=5700, TE=139 msec), providing images with diffusion sensitivity values (b values) of 0.50 sec/mm2, 500 sec/mm2, and 1000 sec/mm2. Also, automated apparent diffusion coefficient (ADC) maps were provided by this sequence.
Discussion
In ischemia cytotoxic edema develops in the involved region. Cytotoxic edema is associated with restriction of the mobility of water molecules, therefore high signal is observed on true diffusion images (i.e. b=1000 sec/mm2 images), and low signal is seen on corresponding ADC maps with low ADC values. On the other hand, leukoariasis (white matter hyperintensities) is commonly seen in the periventricular regions of elderly, and on ADC maps of diffusion MRI these have high signal, while they may not be apparent on true diffusion (b=1000 sec/mm2) images. Both, acute infarction and leukoariasis have high signal on T2-weighted images, however, their discrimination is possible using the b=500 sec/mm2 , and b=1000 sec/mm2 images, and ADC maps.
Differential Diagnosis List
Acute infarct and leukoariasis
Final Diagnosis
Acute infarct and leukoariasis
Case information
URL: https://eurorad.org/case/651
DOI: 10.1594/EURORAD/CASE.651
ISSN: 1563-4086