Effective and efficient diagnosis of parkinsonism: the role of dopamine transporter SPECT imaging with ioflupane I-123 injection (DaTscan™)

Abstract

Parkinson's disease (PD), the second-most common neurodegenerative disease, is characterized by motor and nonmotor symptoms. PD is often misdiagnosed; inappropriate treatment due to misdiagnosis has undesired consequences, as does delayed diagnosis. Unfortunately, most people with PD receive a diagnosis only after motor symptoms have emerged, by which time 40% to 60% of dopamine neurons have already been lost. Advances in imaging techniques have provided clinicians with increasingly sophisticated tools. In 2011, the US Food and Drug Administration approved ioflupane I-123 injection (DaTscanTM) for striatal dopamine transporter visualization using single-photon emission computed tomography (SPECT) imaging, which provides an effective tool for assessing striatal dopaminergic deficiency. Among patients with suspected parkinsonian syndromes, of which PD is one, the diagnostic sensitivity and specificity of DaTscan SPECT imaging are high. In clinical studies that were part of the DaTscan new drug application, no serious drug-related adverse events reported by the 1236 participants were attributed to DaTscan. The introduction of DaTscan imaging and its utility necessitate the development of clinical recommendations for appropriate use; thus, a multidisciplinary panel of experts was convened to develop clinical criteria and algorithms to help guide clinicians and managed care organizations in the application of DaTscan SPECT imaging. Based on the consensus of this expert panel, appropriate use of DaTscan SPECT imaging includes cases where: (1) PD diagnosis is uncertain; (2) tremor of uncertain etiology is present; and (3) nonmotor and/ or supportive symptoms and features associated with PD are present but the classical motor syndrome is absent or atypical.