The feasibility of anterior 180° 99m Tc-sestamibi parathyroid SPECT/CT.

OBJECTIVE: For 99mTc-sestamibi parathyroid single photon emission computed tomography/computed tomography (SPECT/CT), the traditional full-arc 360° acquisition technique has been suggested but not the theoretically low tissue-attenuated anterior 180° method. We aimed to compare the diagnostic performances and target-to-background ratios of anterior 180° and 360° SPECT/CT imaging. METHODS: Ninety-nine patients who underwent 99mTc-sestamibi scintigraphy and received a surgical-pathological diagnosis of parathyroid adenoma or hyperplasia were enrolled. The SPECT/CT reconstructed images with anterior 180° and full-arc 360° data were interpreted by two physicians using a scoring scale, and the lesions were semi-quantified using target-to-background ratios for both image sets. RESULTS: In total, 113 abnormal parathyroid lesions were identified on the SPECT/CT images. The agreements of interpretation between the two image sets and readers were very good (κ value: 0.83-1.00). The accuracies of summative interpretation for the anterior 180° and full-arc 360° SPECT/CT were 83.04% and 82.46%, respectively. The target-to-background ratios were significantly higher for the anterior 180° than the full-arc 360° images (P < 0.01). CONCLUSIONS: The anterior 180° SPECT/CT technique, a time-saving method, can provide satisfactory diagnostic performance and superior lesion contrast compared with the full-arc 360° SPECT/CT technique in 99mTc-sestamibi parathyroid imaging.

Neurotoxicity of carbon monoxide targets caudate-mediated dopaminergic system.

The clinical features of parkinsonism in carbon monoxide (CO) intoxication have been associated with striatal-related neuronal networks. As parkinsonian and neuropsychiatric features are both related to presynaptic dopaminergic integrity, the aim of this study was to explore the clinical significance of 99mTcTRODAT-1 in grading neurobehavioral scores and parkinsonian severity in CO intoxication. We enrolled 64 patients with CO intoxication, including 29 with parkinsonism (parkinsonism[+] group) and 35 without (parkinsonism[-] group). All of the patients received 99mTcTRODAT-1 neuroimaging evaluations, comprehensive neurobehavioral tests and assessments of the severity of parkinsonism using Unified Parkinson's Disease Rating Scale (UPDRS)-part III motor score. Univariate and multivariate regression analyses were used to test the predictive factors and scores for a diagnosis of parkinsonism and its severity. The parkinsonism(+) group had significantly lower cognitive scores and higher neuropsychiatric total scores compared with the parkinsonism(-) group, both of which were independently related to the severity of parkinsonism. 99mTcTRODAT-1 regional caudate signals were correlated with tremors at rest, action or postural tremors of the hands, bradykinesia and hypokinesia, and visuospatial, verbal fluency, abstract thinking and digit backwards scores. Scores of the neurobehavioral tests and UPDRS items were highly correlated (p<0.01). Our results validated the initial hypothesis in that neurobehavioral deficits and parkinsonian symptoms were highly related. This association was independent of demographic factors and initial carboxyhemoglobin level. Within the presynaptic dopaminergic circuit, the clinical role of the caudate in mediating the clinical symptoms in CO intoxication may outweigh the putamen.