MRI Protocol for Multiple Sclerosis Diagnosis and Monitoring

Standard MRI Protocol Components for MS

T2-weighted sequences should be acquired in at least two planes, with axial T2 and proton-density (and/or T2-FLAIR) scans combined with sagittal T2-FLAIR being the optimal strategy 1, 2
Single-slab isotropic 3D T2-FLAIR (voxel size = 1 mm³) could replace 2D T2-FLAIR sequences for better spatial resolution 2
T2-weighted sequences are more sensitive than T1-weighted ones for demonstrating MS lesions 3
Gadolinium-enhanced (single dose, 0.1 mmol/kg body weight) T1-weighted spin-echo sequences are mandatory in the initial study when lesions are seen on T2-weighted sequences 1, 2
A minimum delay time of 5 minutes is recommended between gadolinium injection and T1-weighted sequence acquisition 1, 2, 3

Contrast enhancement allows acute lesions to be distinguished from chronic ones, demonstrating dissemination in time (DIT) 1, 2, 4
The pattern of enhancement helps in differential diagnosis from other conditions that can mimic MS 1, 4
Enhancement occurs in almost all new lesions which appear during serial monthly scans of patients with relapsing-remitting or secondary progressive MS 3
In follow-up studies, a postcontrast T1-weighted sequence, though not strictly mandatory, is highly recommended as it facilitates visual detection of new active lesions 1
Contrast enhancement is a short-lived feature (typically 2-8 weeks) in most MS lesions, thus helping differentiate recent from older lesions 4, 5

An enhancing MS lesion is defined as an area of at least 3 mm with clear hyperintensity on T1-weighted images obtained at least 5 minutes after contrast agent administration 4, 5
Enhancing MS lesions are often nodular, though larger ones can evolve into ring-enhancing lesions 5, 6
Larger lesions may show "open-ring" enhancement (open towards ventricles or gray matter), which helps differentiate from neoplastic lesions or abscesses 5, 6

Safety concerns regarding gadolinium administration and its tendency to accumulate in the brain can be mitigated by using macrocyclic rather than linear agents 4, 5
Controlling the frequency of gadolinium administration at follow-up is recommended 4, 5
Lesions that enhance for longer than 3 months are exceptional and should raise suspicion of alternative pathology 4, 5

For spinal cord imaging, contrast-enhanced T1-weighted spin-echo is recommended if T2 lesions are present 7
Mandatory sequences include dual-echo (proton-density and T2-weighted) conventional and/or fast spin-echo, STIR, and contrast-enhanced T1-weighted spin-echo (if T2 lesions present) 7

The American College of Radiology recommends using FLAIR with contrast to detect leptomeningeal enhancement, active inflammatory lesions, and disruptions of the blood-brain barrier, especially when administered with a delay of at least 5 minutes after gadolinium injection 8

The European Society of Radiology notes that FLAIR with contrast detects edema, demyelination, and ischemic lesions without the need for contrast, and is superior to conventional T2 sequences for detecting juxtacortical and periventricular lesions 9, 10

The National Institute of Neurological Disorders and Stroke guidelines suggest that FLAIR with contrast has a sensitivity of 96% and specificity of 85.71% for diagnosing meningitis, compared to 68% sensitivity of T1 with contrast 8
The American Academy of Neurology recommends using FLAIR with contrast to distinguish acute active lesions from chronic lesions in multiple sclerosis, demonstrating dissemination in time 9

The International Society for Magnetic Resonance in Medicine recommends acquiring FLAIR pre-contrast first, followed by T1 pre-contrast, then administering gadolinium and waiting a minimum of 5 minutes before acquiring T1 post-contrast, and finally FLAIR post-contrast 9, 10

The European Society of Radiology guidelines recommend evaluating renal function before administering gadolinium 8