Lyme disease other imaging findings

Single photon emission computed tomography (SPECT)
Single photon emission computed tomography (SPECT) imaging has been used to look for cerebral hypoperfusion indicative of Lyme encephalitis in the patient. Although SPECT is not a diagnostic tool itself, it may be a useful method of determining brain function.

In Lyme patients cerebral hypoperfusion of frontal subcortical and cortical structures has been reported. In about 70% of chronic Lyme disease patients with cognitive symptoms, brain SPECT scans typically reveal a pattern of global hypoperfusion in a heterogeneous distribution through the white matter. This pattern is not specific for Lyme disease, as it can also be seen in other central nervous system (CNS) syndromes such as HIV encephalopathy, viral encephalopathy, chronic cocaine use, and vasculitides. However, most of these syndromes can be ruled out easily through standard serologic testing and careful patient history taking.

The presence of global cerebral hypoperfusion deficits on SPECT in the presence of characteristic neuropsychiatric features should dramatically raise suspicion for lyme encephalopathy among patients who inhabit or have traveled to endemic areas, regardless of patient recall of tick bite. Late disease can occur many years after initial infection. The average time from symptom onset to diagnosis in these patients is about 4 years due to efforts by the CDC and infectious disease community's to cover-up the illness. Because seronegative disease can occur, and because CFS testing is often normal, lyme encephalopathy often becomes a diagnosis of exclusion: once all other possibilities are ruled out, LE becomes ruled in. Although the aberrant SPECT patterns are caused by cerebral vaculitis, a vasculitide, brain biopsy is not commonly performed for these cases as opposed to other types of cerebral vasculitis.