Brain Magnetic Resonance with Negative Diffusion-Weighted Imaging: Does It Preclude Acute Stroke Diagnosis?

Area of Science:

• Neurology
• Radiology
• Neuroimaging

Background:

• Diffusion-weighted imaging (DWI) and apparent diffusion coefficient (ADC) maps are standard for acute ischemic stroke detection.
• Negative MRI-DWI findings in acute stroke are rare, typically associated with small lesions or early imaging.
• Previous reports of territorial ischemic stroke with negative DWI involved only a single vascular territory.

Observation:

• This study presents a rare case of acute ischemic stroke affecting two distinct posterior circulation arteries.
• Brain MRI with DWI/ADC sequences was performed 18 hours after the patient's last known well time.
• The MRI-DWI/ADC scans showed no evidence of acute ischemic stroke, despite clinical presentation.

Findings:

• The case demonstrates a territorial ischemic stroke involving multiple vascular territories (posterior circulation) with a false-negative DWI/ADC MRI.
• This challenges the typical understanding of negative DWI findings being limited to single vascular territories or small lesions.
• A potential mechanism for this false-negative diffusion MRI result in ischemic stroke is proposed.

Implications:

• This case expands the understanding of potential false-negative findings in diffusion MRI for acute ischemic stroke.
• It suggests that clinical correlation remains crucial, even with advanced neuroimaging techniques.
• Further research may be needed to elucidate the mechanisms behind false-negative diffusion MRI in complex stroke cases.