Would an mri of the brain for ms lesions be acceptable without contrast? no were lesions found, however, no contrast was used.

It depends.: In the initial evaluation of suspected MRI, contrast is recommended for several reasons, such as the detection of potentially confounding diagnoses(e.g. leptomeningeal processes) that may be invisible on noncontrast MRI, and also for classification/prognostic information if MS is present. For follow up of known MS, contrast may or may not be necessary depending on the clinical situation.