Ioflupane 123I (DAT scan) SPECT identifies dopamine receptor dysfunction early in the disease course in progressive apraxia of speech.

OBJECTIVE: To describe 123I-FP-CIT (DAT scan) SPECT findings in progressive apraxia of speech (PAOS) patients and to compare those findings with progressive supranuclear palsy (PSP) and corticobasal syndrome (CBS). BACKGROUND: PAOS is a neurodegenerative syndrome in which patients present with apraxia of speech, a motor speech disorder affecting programming and planning of speech. Patients with PAOS predictably develop Parkinsonism. DAT scan is a neuroimaging tool that assesses the integrity of presynaptic dopamine transporters in striatum and is usually abnormal in PSP and CBS. METHODS: As part of an NIH-funded grant, we performed a DAT scan on 17 PAOS patients early in the disease course. DaTQUANT software was used to quantify uptake in the left and right caudate and anterior/posterior putamen, with striatum to background ratios (SBRs). The PAOS cohort was compared to 15 PSP and 8 CBS patients. RESULTS: Five PAOS patients (29%) showed abnormalities in at least one striatal region on DAT scan. When the five PAOS patients with abnormal DAT were compared to the PSP and CBS patients, the only difference observed was lower uptake in the posterior putamen in PSP (p = 0.03). There were no differences is putamen/caudate ratio or in symmetry of uptake, across all groups. There was also no difference in MDS-UPDRS-III scores between PAOS patients with and without abnormal DAT scans (p = 0.56). CONCLUSIONS: Abnormal DAT scan is observed early in the disease course in approximately 30% of PAOS patients, with striatal abnormalities similar to those in PSP and CBS.

Confirmation of 123I-FP-CIT SPECT Quantification Methods in Dementia with Lewy Bodies and Other Neurodegenerative Disorders.

Our rationale was to conduct a retrospective study comparing 3 123I-N-ω-fluoropropyl-2ß-carbomethoxy-3ß-(4-iodophenyl)nortropane (123I-FP-CIT) SPECT quantitative methods in patients with neurodegenerative syndromes as referenced to neuropathologic findings. Methods:123I-FP-CIT-SPECT and neuropathologic findings among patients with neurodegenerative syndromes from the Mayo Alzheimer Disease Research Center and Mayo Clinic Study of Aging were examined. Three 123I-FP-CIT SPECT quantitative assessment methods-MIMneuro, DaTQUANT, and manual region-of-interest creation on a workstation-were compared with neuropathologic findings describing the presence or absence of Lewy body disease (LBD). Striatum-to-background ratios (SBRs) generated by DaTQUANT were compared with the calculated SBRs of the manual method and MIMneuro. The left and right SBRs for caudate, putamen, and striatum were evaluated with the manual method. For DaTQUANT and MIMneuro, the left, right, total, and average SBRs and z scores for whole striatum, caudate, putamen, anterior putamen, and posterior putamen were calculated. Results: The cohort included 24 patients (20 [83%] male, mean age for all patients at death, 75.4 ± 10.0 y). The antemortem clinical diagnoses were Alzheimer disease dementia (n = 6), probable dementia with Lewy bodies (n = 12), mixed Alzheimer disease dementia and probable dementia with Lewy bodies (n = 1), Parkinson disease with mild cognitive impairment (n = 2), corticobasal syndrome (n = 1), idiopathic rapid-eye-movement sleep behavior disorder (n = 1), and behavioral-variant frontotemporal dementia (n = 1). Seventeen (71%) had LBD. All 3 123I-FP-CIT SPECT quantitative methods had an area under the receiver-operating-characteristics curve ranging from more than 0.93 to up to 1.000 (P < 0.001) and showed excellent discrimination between LBD and non-LBD patients in each region assessed (P < 0.001). There was no significant difference between the accuracy of the regions in discriminating the 2 groups, with good discrimination for both caudate and putamen. Conclusion: All 3 123I-FP-CIT SPECT quantitative methods showed excellent discrimination between LBD and non-LBD patients in each region assessed, using both SBRs and z scores.

Clinicopathological and 123I-FP-CIT SPECT correlations in patients with dementia.

The relationship between clinicopathologic diagnosis and 123I-FP-CIT SPECT in 18 patients with dementia (12 with Lewy body disease) from one center in the United States was assessed. The sensitivity and specificity of abnormal 123I-FP-CIT SPECT with reduced striatal uptake on visual inspection for predicting Lewy body disease were 91.7% and 83.3%, respectively. The mean calculated putamen to occipital ratio (mPOR) based on regions of interest was significantly reduced in Lewy body disease compared to non-Lewy body disease cases (P = 0.002). In this study, abnormal 123I-FP-CIT SPECT was strongly associated with underlying Lewy body disease pathology, supporting the utility of 123I-FP-CIT SPECT in the clinical diagnosis of dementia with Lewy bodies.

Early image acquisition using a solid-state cardiac camera for fast myocardial perfusion imaging.

BACKGROUND: A novel ultra-fast solid-state cardiac camera (Discovery NM 530c, General Electric) allows much shorter acquisition times compared to standard dual-detector SPECT cameras. This design enables investigation of the potential for early myocardial perfusion imaging (MPI) following a rest injection of technetium-99m (Tc-99m) rather than the conventional 45-60 minute delay in image acquisition. METHODS: A total of 30 patients underwent MPI at rest using Tc-99m sestamibi (n = 9) or tetrofosmin (n = 21). A 12 minute image acquisition in list mode was performed immediately following isotope injection. Patients also underwent a conventional delayed image acquisition 60 minutes following the rest isotope injection (image acquisition over 4 minutes). The immediate 12 minute acquisition was divided into three 4-minute intervals for image reconstruction (0-4, 4-8, and 8-12 minutes). The perfusion images were interpreted by two experienced physicians who evaluated each study for overall image quality (good, acceptable, or unacceptable) and graded each image using the summed rest score (SRS) and the standard 17-segment, 5-point scale model. RESULTS: The images acquired in the 0-8 minute time interval were predominantly uninterpretable due to excessive blood pool uptake. The images acquired in the 8-12 minute time interval were interpretable and compared to the conventional images obtained at 60 minutes. Overall image quality was better on the 60 minute image (17 good, 13 acceptable) compared with 8-12 minute image (3 good, 25 acceptable, 2 unacceptable). Sixteen of the 30 patients had an improvement in overall image quality by at least one category using the 60 minute delayed image. Nine of the 30 patients (2 Tc-99m sestamibi; 7 Tc-99m tetrofosmin) had at least one uninterpretable myocardial segment due to liver and/or bowel overlapping the myocardium on the 8-12 minute images vs 1 patient (1 myocardial segment) with this problem on the 60 minute delayed images (P = .005). Uninterpretable segments (total of 16) on the 8-12 minute images were confined to the apex and inferior wall. The mean SRS of the interpretable 8-12 minute images (n = 21) was 3.2 (95% confidence intervals; 1.0, 5.4) compared to 1.6 (95% confidence intervals; 0, 3.3) on the 60 minute delayed images in those patients (P = .005). CONCLUSIONS: Overall image quality was better with fewer uninterpretable studies and a lower SRS on the rest images obtained at 60 minutes compared to early image acquisition (8-12 minutes following isotope injection). These findings do not support the routine use of early image acquisition with this new solid-state ultra-fast camera system.