MRI Without Contrast for Mild Neurocognitive Disorder
No, IV contrast is not indicated for initial imaging of patients with mild neurocognitive disorder (MCI). MRI brain without IV contrast is the recommended imaging study. 1
Primary Recommendation
The American College of Radiology 2024 guidelines explicitly state that IV contrast material is not generally necessary for the initial imaging of patients with MCI not meeting criteria for dementia. 1 The recommended approach is:
- MRI brain without IV contrast as the preferred initial imaging modality 1, 2
- CT head without IV contrast as an acceptable alternative when MRI is unavailable or contraindicated 1, 2
Rationale for Non-Contrast Imaging
The goals of imaging in MCI are fully achieved without contrast administration:
- Exclude treatable structural abnormalities that could mimic MCI (tumors, subdural hematomas, normal pressure hydrocephalus) 1, 2
- Demonstrate atrophy patterns in medial temporal lobes, lateral temporal and parietal cortices that increase likelihood of progression to dementia 1, 2
- Assess vascular burden using white matter hyperintensity evaluation (Fazekas scale) 2
- Detect microhemorrhages critical for patient selection if antiamyloid therapy is later considered 2
When Contrast May Be Appropriate
The only scenario where contrast-enhanced MRI is recommended in the dementia evaluation pathway is for rapidly progressive dementia (RPD), where MRI brain without and with IV contrast is indicated to evaluate for infectious, inflammatory, or neoplastic causes. 1 This is distinctly different from the MCI population.
Advanced Imaging Considerations
For MCI patients, if additional diagnostic information is needed beyond structural imaging:
- Brain amyloid PET/CT and brain FDG-PET/CT are complementary modalities with greater accuracy at predicting conversion to Alzheimer's disease 1
- These functional imaging studies are more appropriate than adding contrast to MRI 1
Important Clinical Caveats
- MR spectroscopy and functional MRI are not recommended for initial imaging in MCI patients 1
- Most patients over age 80 with cognitive impairment have mixed pathology, making single-modality diagnosis challenging 2
- Specific molecular biomarkers remain necessary to confirm Alzheimer's disease diagnosis despite supportive MRI findings 2