Vascular Changes Seen on Brain MRIs of Lyme Patients
The findings on a Lyme disease MRI vary amongst individuals but may show evidence of cerebral atrophy, including abnormal signalling within the white matter of the brain and in the brain stem. This loss of signalling function may be due to demyelination, or alterations in vascularity in the brain. Some patients may have calcification of areas of the brain which compromise cognitive function. The alterations in brain structure, lesion development, demyelination, and abnormalities in brain signals may cause some physicians to consider Multiple Sclerosis as a differential diagnosis, or even stroke in patients at risk of such an event. The similarities between Lyme disease and MS, as well as with other illnesses makes diagnosis very complex, particularly where no initial symptoms, such as erythema migrans or flu-like illness are recalled by the patient.
Lyme Disease MRIs Look Similar to MS, CFS, and Fibromyalgia ScansMRI scans of the brain tissue of Lyme disease patients share such similarities with patients with MS, chronic fatigue syndrome, and even fibromyalgia, that it may be the resolution of these lesions following antibiotic treatment that actually confirms that they were caused by an infection rather than some other pathology. Lesions in the white matter of the brain can disrupt gray matter connections and may be at the root of some Lyme disease symptoms such as mood irregularities, memory problems, cognitive difficulties, and attention deficit. Neuronal loss is thought less common in white matter disease which would make for a better recovery following antibiotic treatment for Lyme disease patients with hyperintensive foci on a Lyme disease MRI. Changes on a Lyme disease MRI scan may be slow to occur however, and the reversal of damage caused by neuroborreliosis can take a year or more to show up as brain tissue heals.
What Can Lyme Disease MRI Scans Tell Us?
Lyme disease MRI scans showing hyperintensive signal areas in the white matter and/or the brain stem, on T2-weighted images, should prompt a physician to consider neuroborreliosis as the diagnosis. Each tissue in the human body has its own T1 and T2 value. When an image shows most contrast between tissues in terms of their T1 value it is deemed to be T1-weighted, a T2-weighted image is where most differences occur in the T2 values of tissues. There are concerns however that these terms may be misleading and contingent upon the parameters of the MRI machine used for testing. Different types of lesions that may show brightly on T1-weighted MRI scans include those caused by fat (lipoma, dermoid), sub-acute haemorrhage (metHb), paramagnetic agent (Gd, pituitary), protein-containing fluid (colloid cyst), and metastatic melanoma (melanotic). Understanding such markers is essential for applying the correct diagnosis of a condition and administering prompt and appropriate treatment.
Identifying Lyme Disease Markers on MRI Scans
Identifying MRI markers of MS has relied largely on spotting hyperintensive lesions on T2-weighted MRIs in recent years, despite their weak clinical correlation. Researchers have begun to use an alternative protocol whereby bright spots on T1-weighted MRI scans of MS patients appear to correlate significantly with the physical debility of patients and brain atrophy. Having a relevant biomarker for detecting MS in patients makes it less likely that they will be misdiagnosed with the disease when they are actually suffering from infection with Lyme disease, or that treatment for MS will be delayed as other conditions remain a possible differential diagnosis.
MRI Scans for Patients with CFS and Depression
Some patients suffering from depression and chronic fatigue may undergo MRI scans or CT scans if they have a history suggestive of Lyme disease, or the findings may be coincidental if an alternative cerebral issue is being investigated. CT scans are not considered adequate in testing for Lyme disease encephalitis however, and the use of SPECT scans for Lyme disease are highly questionable. Where an area of hyperintensive signal is apparent on a Lyme disease MRI, the patient may then undergo serological testing for Lyme titers using either blood or cerebrospinal fluid (CSF). Antibiotic treatment for Lyme disease may then begin to resolve the symptoms of depression and chronic fatigue that a patient may have begun to consider permanent and incurable.
A review of MRI scans and clinical outcome, carried out by Agarwal and Sze (2009), of nearly 400 patients with suspected neuro-Lyme disease found 66 patients proved to have the condition on the basis of Lyme disease tests (serological), clinical features, and response to antibiotics. Of these 66 patients, seven showed evidence of lesions in the cerebral white matter, with one patient found to have an enhancing lesion with oedema, and three with nerve-root or meningeal enhancement on the MRI scan. The authors of the paper suggest that Lyme disease should be considered a differential diagnosis when nerve-root or meningeal enhancement is evident on MRI.
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