Unexpected (123I)FP-CIT SPECT findings: SWIDD, SWEDD and all DAT

AbstractAlthough the diagnosis of Parkinson ’s disease (PD) is essentially clinical, the implementation of imaging techniques can improve diagnostic accuracy. While some techniques (e.g. magnetic resonance imaging—MRI, computerized tomography—CT) are used to exclude secondary syndromes, presynaptic dopaminergic imaging including imaging of dopamine transporter (DAT)—can help the Neurologist in the differential diagnosis between neurodegenerative parkinsonian syndromes and parkinsonism without dopamine deficiency. DAT imaging can be useful in cases in which the clinical picture is not univocal, as in case of overlapping clinical features in patients with early disease, atypical syndromes or unsatisfying response to therapy. Currently, (123I)FP-CIT ([123I]N-ω-fluoropropyl-2β-carbomethoxy-3β-(4-iodophenyl)nortropane) (trade name DaTSCAN) is the only agent approved by international regulatory agencies for this purpose. With the increasing use of this technique, some unexpected findings have been reported, including patients clinically diagnosed with PD with a normal SPECT scan [e.g. Scans Without Evidence of Dopaminergic Deficit (SWEDD)]; PD patients with a greater dopaminergic deficit in the striatum ipsilateral to the clinically  more affected side [e.g. Scans With Ipsilateral Dopaminergic Deficit (SWIDD)]; as well as some artifacts. Moreover, the neurologist must remember that structural lesions and administration of some drugs might alter the result of DAT imaging...
Source: Journal of Neurology - Category: Neurology Source Type: research