Should non-movement specialists refer patients for SPECT-DaTSCAN?

Abstract

Background. SPECT with radioligand DaTSCAN (SPECT-DaTSCAN) is a sensitive tool used for assessing the functional integrity of the presynaptic part of the nigrostriatal dopaminergic system. The procedure is useful whenever there is a need to distinguish between neurodegenerative parkinsonism and other parkinsonian syndromes in subjects with equivocal signs and symptoms. It can be assumed that the neurologist's decision to perform SPECT-DaTSCAN depends on his or her experience and skill in the diagnosis of parkinsonian and tremor syndromes. Aims. To assess the accuracy of referrals to SPECT-DATSCAN made by non-movement disorders specialists. Material and methods. Sixty seven patients referred for SPECT-DaTSCAN by a general neurologist were studied. In all subjects, a movement disorder specialist performed the neurological examination, collected medical history, and analysed previous treatments and the results of diagnostic tests. Results. Evaluation carried out by a movement disorder specialist did not confirm an indication for SPECT-DaTSCAN in 31 patients (46.3%). General neurologists needed support for clinical diagnosis with SPECT-DaTSCAN most frequently in subjects with parkinsonism even though they were presenting a full-blown disease manifestation and even though the patients met the diagnostic criteria for Parkinson's disease or one of the atypical parkinsonian syndromes. Conclusions. Our presented results probably reflect the limited experience of general neurologists in the evaluation of parkinsonian syndromes and tremor. The use of SPECT-DaTSCAN by non-movement disorders specialists is associated with a significant risk of overuse of this tool. To minimise this risk, the skills of general neurologists in diagnosing parkinsonian and tremor syndromes should be improved. Moreover, patients should be provided with access to movement disorders specialists.

Neuroimaging in Parkinson’s Disease: necessity or exaggeration?

“…Most importantly, patients should be primarily examined by specialists experienced in movement disorders, which should result in a significant reduction in the number of performed scans. As we mentioned, up to half of patients referred for this examination by GNs, and further re-examined by movement disorder specialists, did not need any scanning because their clinical histories and symptoms were sufficient to make a proper diagnosis [3].…”

“…Magnetic resonance imaging (MRI) is not recommended criteria in the routine diagnosis of typical levodopa (LD)-responsive PD [1]. Similarly, the widely available dopamine transporter single-photon emission computed tomography (SPECT) using [ 123 I]-FP-CIT (ioflupane), trade name: DaTSCAN should not be used routinely to confirm the diagnosis of PD, and officially is licensed only for the differential diagnosis of PD and Essential Tremor (ET) [1][2][3]. Nevertheless, there is a substantial number of studies looking for specific MRI signs that may be helpful in a diagnosis of PD and differentiate PD from atypical parkinsonian syndromes (APS) such as progressive supranuclear palsy (PSP), multiple system atrophy (MSA), cortico-basal syndrome (CBS) or dementia with Lewy bodies (DLB) and symptomatic parkinsonism.…”

I123‐FP‐CIT (DaTSCAN) SPECT beyond the Most Common Causes of Parkinsonism: A Systematic Review

“…67 Different committees of experts in movement disorders recommend that these kinds of tests be requested only by specialists in these syndromes, particularly in patients with uncertain diagnoses after several evaluations. 67,68 This includes patients showing subtle early symptoms, sub-optimal response to levodopa, a prominent action tremor, pharmacological parkinsonism, and other patients presenting parkinsonism with lower limb predominance or other less frequent clinical manifestations. 69…”

Dissecting parkinsonism: cognitive and gait disturbances

“…Drug-induced parkinsonism can be difficult to distinguish from idiopathic PD, although clues such as a temporal relationship to starting dopamine blocking medications, poor levodopa response, and symmetric parkinsonism should increase the index of suspicion. DaTScan typically shows normal radioisotope uptake, consistent with preserved presynaptic dopaminergic function, in drug-induced parkinsonism and can be helpful in ruling out concurrent neurodegenerative parkinsonism, especially if symptoms are asymmetric [51][52][53]. Cognitively, patients may have comorbid psychiatric disease (those on antipsychotics) or gastrointestinal dysfunction (those on dopamine blocking antiemetics) and demonstrate a variety of medication-related side effects beyond parkinsonism, e.g.…”