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Diagnosis of acute brain-stem infarcts using diffusion-weighed MRI
1Department of Neurosurgery, School of Medicine, The University of Tokushima, 3-18-15 Kuramotocho, Tokushima, Japan 770-8503.
Abstract:
There are many reports on acute cerebral infarcts diagnosed by diffusion-weighted MRI (DWI), but few describe brain-stem infarcts diagnosed by this method. Using the apparent diffusion coefficient (ADC), we studied 18 consecutive patients with brain-stem infarcts who underwent DWI during the acute phase. We calculated and compared the ADC ratio (lesion ADC/contralateral ADC) in 10 patients with brain-stem and 23 with supratentorial cortical infarcts examined within 24 h of the onset of stroke. Ischaemic brain-stem lesions were detected in all 15 patients who underwent DWI more than 3 h after the onset, but not in two who had DWI within 3 h of the onset; their ADC ratio was more than 0.95. ADC ratios in patients with brain-stem infarcts decreased as the interval between onset and DWI increased; the decrease was slower than in patients with supratentorial cortical infarcts.
Insights
Diffusion-weighted MRI (DWI) can detect acute brain-stem infarcts, but detection depends on the time since stroke onset. Apparent diffusion coefficient (ADC) ratios decrease over time, aiding diagnosis.
Area of Science:
- Neurology
- Radiology
- Medical Imaging
Background:
- Diffusion-weighted MRI (DWI) is widely used for acute cerebral infarcts.
- Few studies have focused on diagnosing acute brain-stem infarcts using DWI.
Observation:
- This study examined 18 patients with acute brain-stem infarcts using DWI.
- The apparent diffusion coefficient (ADC) ratio was calculated and compared between brain-stem and supratentorial cortical infarcts.
Findings:
- Ischaemic brain-stem lesions were detected in 15/17 patients undergoing DWI >3 hours post-onset.
- Two patients with DWI <3 hours post-onset showed no lesion detection (ADC ratio >0.95).
- Brain-stem infarct ADC ratios decreased over time, but at a slower rate than supratentorial infarcts.
Implications:
- DWI is effective for diagnosing acute brain-stem infarcts, particularly when performed >3 hours after stroke onset.
- ADC ratio changes over time can aid in the diagnosis and timing of brain-stem infarcts.
- Findings may improve the diagnostic accuracy and clinical management of brain-stem strokes.