Human brain infarcts: Gd-DTPA-enhanced MR imaging

Area of Science:

• Neuroradiology
• Medical Imaging
• Neurology

Background:

• Gadolinium-based contrast agents are utilized in Magnetic Resonance (MR) imaging to improve visualization of various pathologies.
• Cerebral infarcts, particularly subacute and chronic stages, present diagnostic challenges with conventional MR imaging techniques.

Purpose of the Study:

• To evaluate the efficacy of gadolinium-DTPA enhanced MR imaging in detecting and characterizing subacute and chronic cerebral infarcts.
• To compare the enhancement patterns of gadolinium-DTPA with computed tomography (CT) contrast enhancement.

Main Methods:

• Phase II and III clinical trials involving 11 patients with 20 cerebral infarcts (subacute and chronic).
• MR imaging (spin-echo sequences) performed 4-30 days post-ictus, with and without gadolinium-DTPA contrast administration.
• Comparison of MR imaging findings with concurrent CT scans, where available.

Main Results:

• Non-enhanced MR images often failed to demonstrate infarcts.
• Gadolinium-enhanced MR images generally matched contrast-enhanced CT findings.
• Chronic, asymptomatic periventricular and deep white-matter lesions showed no enhancement.
• Three small, symptomatic lacunar infarcts (capsular and brain-stem) demonstrated clear enhancement.
• Enhancement peaked around 30 minutes, with variations based on infarct age (8-30 days).
• T2-weighted sequences were sensitive but lacked specificity without contrast.

Conclusions:

• Gadolinium-DTPA enhanced MR imaging is valuable for detecting symptomatic acute and subacute cerebral infarcts.
• This contrast agent is less effective for visualizing chronic, asymptomatic white-matter lesions.
• Timing of imaging post-contrast administration influences the visibility of enhancement in infarcts of different ages.