Single-photon Emission Computed Tomography Uptake Research Articles

Analysis of small abdominal aortic aneurysms with the radiotracer technetium-99m- 6-hydrazinylnicotinoyl-C-C-chemokine receptor-2 ligand (99mTc-HYNIC-CCR2-L) with single-photon emission computed tomography.

Monocyte chemoattractant protein-1 (MCP-1/CCL2) plays a key role for infiltration of monocytes/macrophages and studies have demonstrated that the MCP-1/C-C chemokine receptor 2 (CCR2) axis might be involved in the pathogenesis and progression of abdominal aortic aneurysms (AAA). Molecular imaging has shown potential for human clinical research studies. We evaluated the expression of CCR2 in patients with small AAA using single-photon emission computed tomography (SPECT) with the technetium-99m-6-hydrazinylnicotinoyl-C-C-chemokine receptor-2 ligand (99mTc-HYNIC-CCR2-L). A pilot study was performed to evaluate patients with small asymptomatic AAA. The equipment used was a Symbia T2 (Siemens, Germany), with radiolabeled 99mTc-HYNIC-CCR2-L. The SPECT uptake and activity were assessed and counted based on the region of interest (ROI), with nonparametric statistics being employed to compare the aneurysms site, left ventricle (Control 1) and regions with a nondiseased aorta (Control 2). The three patients were male (100%) (mean age 81 years, and mean AAA maximum diameter of 40 mm, SD 3 mm). All patients tolerated the studies well. Images were obtained at one, two and four hours. The ROI mean value of the aneurysm site was 37,783 (SD 11,890), compared to the left ventricle (Control 1) 16,779 (SD 4397) (p-value = 0.0001); ROI for the nondiseased aortic region (Control 2) was significantly lower, 12,520 (SD 2141) (p-value = 0.0001). Significant differences of CCR2 expression SPECT were found in the AAA site compared to the left ventricle and nondiseased aortic segments. The introduction of well-designed longitudinal studies with nuclear imaging modalities may assist in the molecular characterization of aneurysmal and rupture prediction.

Evaluation of optimal single-photon emission computed tomography reference value and three-dimensional mandibular growth pattern in 54 Chinese unilateral condylar hyperplasia patients

BackgroundThe research aimed to evaluate the optimal Single-Photon Emission Computed Tomography (SPECT) cut-off value in differentiating condylar growth activeness, to observe 3-dimensional (3D) mandibular growth pattern, and to explore the potential correlation between 3D measurement parameters and SPECT uptake ratios in Chinese unilateral condylar hyperplasia (UCH) patients.Methods Data of fifty-four Chinese UCH patients were analyzed retrospectively. All patients underwent SPECT within 1 month before or after the first CT examination (CT1); and received a second CT examination at least 12 months later (CT2). Data from CT scans were analyzed by comparing bilateral differences between CT1 and CT2. The sensitivity and specificity of SPECT were calculated by the receiver operating characteristic (ROC) curve. Pearson’s correlation analysis was performed to investigate whether the mandibular growth was correlated with SPECT value.ResultsSPECT had a sensitivity of 68.00% and a specificity of 72.41%, with an area under the ROC curve being 0.709. The optimal SPECT cut-off value for evaluating condylar activity has been determined to be 13%. In patients with an active growing condyle, there was a significant increase in Co-Gn and Co-Go, but not in Go-Gn, Go-MF, or MF-Gn. Pearson’s correlation analysis revealed no correlation between 3D measurement parameters and differences in relative condylar uptake ratios.ConclusionSPECT showed good diagnostic performance in UCH with the cut-off value of 13%. For those with an active growing condyle, the mandible grows diagonally and vertically, while the relative condylar uptake ratio was not directly related to mandibular growth.

SPECT imaging of lung ischemia-reperfusion injury using [99mTc]cFLFLF for molecular targeting of formyl peptide receptor 1.

Primary graft dysfunction after lung transplantation, a consequence of ischemia-reperfusion injury (IRI), is a major cause of morbidity and mortality. IRI involves acute inflammation and innate immune cell activation, leading to rapid infiltration of neutrophils. Formyl peptide receptor 1 (FPR1) expressed by phagocytic leukocytes plays an important role in neutrophil function. The cell surface expression of FPR1 is rapidly and robustly upregulated on neutrophils in response to inflammatory stimuli. Thus, we hypothesized that use of [99mTc]cFLFLF, a selective FPR1 peptide ligand, would permit in vivo neutrophil labeling and noninvasive imaging of IRI using single-photon emission computed tomography (SPECT). A murine model of left lung IRI was utilized. Lung function, neutrophil infiltration, and SPECT imaging were assessed after 1 h of ischemia and 2, 12, or 24 h of reperfusion. [99mTc]cFLFLF was injected 2 h before SPECT. Signal intensity by SPECT and total probe uptake by gamma counts were 3.9- and 2.3-fold higher, respectively, in left lungs after ischemia and 2 h of reperfusion versus sham. These values significantly decreased with longer reperfusion times, correlating with resolution of IRI as shown by improved lung function and decreased neutrophil infiltration. SPECT results were confirmed using Cy7-cFLFLF-based fluorescence imaging of lungs. Immunofluorescence microscopy confirmed cFLFLF binding primarily to activated neutrophils. These results demonstrate that [99mTc]cFLFLF SPECT enables noninvasive detection of lung IRI and permits monitoring of resolution of injury over time. Clinical application of [99mTc]cFLFLF SPECT may permit diagnosis of lung IRI for timely intervention to improve outcomes after transplantation.

Regional Radiation Dose-Response Modeling of Functional Liver in Hepatocellular Carcinoma Patients With Longitudinal Sulfur Colloid SPECT/CT: A Proof of Concept

Hepatotoxicity risk in patients with hepatocellular carcinoma (HCC) is modulated by radiation dose delivered to normal liver tissue, but reported dose-response data are limited. Our prior work established baseline [99mTc]sulfur colloid (SC) single-photon emission computed tomography (SPECT)/computed tomography (CT) liver function imaging biomarkers that predict clinical outcomes. We conducted a proof-of-concept investigation with longitudinal SC SPECT/CT to characterize patient-specific radiation dose-response relationships as surrogates for liver radiosensitivity. SC SPECT/CT images of 15 patients with HCC with variable Child-Pugh (CP) status (8 CP-A, 7 CP-B/C) were acquired in treatment position before and 1month (nominal) after stereotactic body radiation therapy (n=6) or proton therapy (n=9). Localized rigid registrations between pre/posttreatment CT to planning CT scans were performed, and transformations were applied to pre/posttreatment SC SPECT images. Radiation therapy doses were converted to EQD2 and Gy RBE (relative biological effectiveness) and binned in 5 GyEQD2 increments within tumor-subtracted livers. Mean dose and percent change (%ΔSC) between pre- and posttreatment SPECT uptake, normalized to regions receiving <5 GyEQD2, were calculated in each binned dose region. Dose-response data were parameterized by sigmoid functions (double exponential) consisting of maximum reduction (%ΔSCmax), dose midpoint (Dmid), and dose-response slope (αmid) parameters. Individual patient sigmoid dose-response curves had high goodness-of-fit (median R2=0.96, range 0.76-0.99). Large interpatient variability was observed, with median (range) in %ΔSCmax of 44% (20%-75%), Dmid of 13Gy (4-27 GyEQD2), and αmid of 0.11 GyEQD2-1 (0.04-0.29 GyEQD2-1), respectively. Eight of 15 patients had %ΔSCmax of 20% to 45%, whereas 7 of 15 had %ΔSCmax of 60% to 75%, with subgroups made up of variable baseline liver function status and radiation treatment modality. Fatal hepatotoxicity occurred in patients (2 of 15) with low total liver funcation (<0.12) and low Dmid (<7 GyEQD2). Longitudinal SC SPECT/CT imaging revealed patient-specific variations in dose-response and may identify patients with poor baseline liver function and increased sensitivity to radiation therapy. Validation of this regional liver dose-response modeling concept as a surrogate for patient-specific radiosensitivity has potential to guide HCC therapy regimen selection and planning constraints.

Development of an 123I-metaiodobenzylguanidine Myocardial Three-Dimensional Quantification Method for the Diagnosis of Lewy Body Disease.

Objective(s):We recently developed a new uptake index method for 123I-metaiodobenzylguanidine (123I-MIBG) heart uptake measurements by using planar images (radioisotope angiography and planar image) for the diagnosis of Lewy body disease (LBD), including Parkinson’s disease (PD) and dementia with Lewy bodies (DLB). However, the diagnostic accuracy of the uptake index was approximately equal to that of the heart-to-mediastinum ratio (H/M) for the discrimination of the LBD and non-LBD patients. A simple and pain-free uptake index method using 123I-MIBG SPECT images by modifying the uptake index method may show better diagnostic accuracy than the planar uptake index method. We hypothesized that the development of a new uptake index method for the determination of 123I-MIBG using single-photon emission computed tomography (SPECT) imaging would provide a reliable and reproducible diagnostic tool for clinical application. Regarding this, the purpose of this study was to develop a new uptake index method with a simple protocol to determine 123I-MIBG uptake on SPECT.Methods:The 123I-MIBG input function was determined from the input counts of the pulmonary artery, assessed by analyzing the pulmonary artery time-activity curves. The 123I-MIBG output function was obtained from 123I-MIBG SPECT counts on the polar map. The uptake index was calculated through dividing the output function by the input function (SPECT uptake method). For the purpose of the study, 77 patients underwent 123I-MIBG SPECT, with an average of 31.5 min after clinical assessment and injection of the tracer. The H/M values, as well as planar and SPECT uptake indices were calculated, and then correlated with clinical features. Results:According to the results, values obtained for LBD were significantly lower than those for non-LBD in all analyses (P<0.01). The overlap of the H/M values between the LBD and non-LBD cases ranged from 2.06 to 2.50. Furthermore, the overlap in uptake index values between LBD and non-LBD cases in planar image analysis was 1.05-1.29. The SPECT uptake index method showed the least overlap of 1.23-1.25, with the highest value for LBD patients clearly distinguished from the lowest value for the non-LBD patients.Conclusion:The new 123I-MIBG SPECT quantification method, developed by the input counts of the pulmonary artery, clearly distinguished LBD from non-LBD. Therefore, this method may be appropriate for routine clinical study.

Regional Variation in Technetium Pyrophosphate Uptake in Transthyretin Cardiac Amyloidosis and Impact on Mortality

ObjectivesThis study sought to investigate the regional uptake of technetium 99m-pyrophosphate (TcPYP) in transthyretin cardiac amyloidosis (ATTR) and its association with mortality. BackgroundTcPYP nuclear scintigraphy is a diagnostic and prognostic tool in ATTR. Echocardiography has identified a pattern of regional variation in longitudinal strain (LS) with a gradient of improved strain from base to apex in ATTR. MethodsConsecutive patients with ATTR were evaluated who underwent TcPYP nuclear scintigraphy with planar and attenuation corrected single-photon emission computed tomography (SPECT). Heart-to-contralateral lung (H/CL) ratio was calculated on planar images, and left ventricular (LV) uptake was determined in each of the 17 segments using SPECT. A measure of apical-sparing of myocardial TcPYP uptake, termed the apical-sparing ratio (ASR), was calculated as basal + mid / apical counts. ResultsOverall, 54 patients with ATTR (age 78 ± 9 years, 76% male, 31% hereditary ATTR) were analyzed. There was increased TcPYP uptake in basal and mid relative to apical LV segments, and an apical-sparing LS pattern on echocardiography. The right ventricle similarly showed greater uptake in basal segments. There were 26 deaths over 1.8 years median follow-up. The ASR of TcPYP uptake was associated with age-adjusted all-cause mortality (p = 0.013) with worse prognosis seen at levels <2.75. Global LS was also prognostic (p = 0.01), whereas H/CL ratio and total LV uptake indexed to blood pool were not (p = 0.772 and p = 0.850, respectively). The prognostic utility of the ASR persisted in multivariable modeling (p = 0.003), whereas global LS did not. ConclusionsThere is decreased TcPYP uptake in apical as compared to mid and basal segments in the LV, mimicking apical-sparing LS seen on echocardiography. Regional distribution of LV TcPYP uptake is associated with mortality, whereas overall amount of uptake as measured by H/CL ratio and indexed LV SPECT uptake is not.

Can DCE-MRI Explain the Heterogeneity in Radiopeptide Uptake Imaged by SPECT in a Pancreatic Neuroendocrine Tumor Model?

Although efficient delivery and distribution of treatment agents over the whole tumor is essential for successful tumor treatment, the distribution of most of these agents cannot be visualized. However, with single-photon emission computed tomography (SPECT), both delivery and uptake of radiolabeled peptides can be visualized in a neuroendocrine tumor model overexpressing somatostatin receptors. A heterogeneous peptide uptake is often observed in these tumors. We hypothesized that peptide distribution in the tumor is spatially related to tumor perfusion, vessel density and permeability, as imaged and quantified by DCE-MRI in a neuroendocrine tumor model. Four subcutaneous CA20948 tumor-bearing Lewis rats were injected with the somatostatin-analog 111In-DTPA-Octreotide (50 MBq). SPECT-CT and MRI scans were acquired and MRI was spatially registered to SPECT-CT. DCE-MRI was analyzed using semi-quantitative and quantitative methods. Correlation between SPECT and DCE-MRI was investigated with 1) Spearman’s rank correlation coefficient; 2) SPECT uptake values grouped into deciles with corresponding median DCE-MRI parametric values and vice versa; and 3) linear regression analysis for median parameter values in combined datasets. In all tumors, areas with low peptide uptake correlated with low perfusion/density/ /permeability for all DCE-MRI-derived parameters. Combining all datasets, highest linear regression was found between peptide uptake and semi-quantitative parameters (R2>0.7). The average correlation coefficient between SPECT and DCE-MRI-derived parameters ranged from 0.52-0.56 (p<0.05) for parameters primarily associated with exchange between blood and extracellular extravascular space. For these parameters a linear relation with peptide uptake was observed. In conclusion, the ‘exchange-related’ DCE-MRI-derived parameters seemed to predict peptide uptake better than the ‘contrast amount- related’ parameters. Consequently, fast and efficient diffusion through the vessel wall into tissue is an important factor for peptide delivery. DCE-MRI helps to elucidate the relation between vascular characteristics, peptide delivery and treatment efficacy, and may form a basis to predict targeting efficiency.

123I-FP-Cit and 123I-IBZM SPECT uptake in a prospective normal material analysed with two different semiquantitative image evaluation tools

The need for age-adjusted and/or sex-adjusted reference values in dopamine transporter (DAT) and dopamine D2 receptor (D2R) imaging with single-photon emission computed tomography (SPECT) in a longitudinal study of parkinsonian diseases was investigated. We used two different image evaluation tools with a cross-sectional and longitudinal statistical approach. Baseline DAT and/or D2R SPECT were performed in 51 healthy controls (HC), age-matched to patients in an ongoing prospective study on idiopathic parkinsonism. Twenty-four HC were re-examined after 3 years and 21 HC were examined again after 5 years. SPECT was performed with I-FP-Cit and I-IBZM on a two-headed hybrid gamma camera. Regions of interest and volumes of interest (VOIs) were used for image evaluation. A cross-sectional and longitudinal statistical analysis was carried out. Fewer sex-based differences and less age dependency were seen in DAT SPECT uptake ratios compared with D2R SPECT uptake ratios and when comparing uptake ratios obtained with regions of interest against those with VOIs. In the cross-sectional analysis, a significant age-dependent decline was seen in women in both DAT and D2R uptakes with the VOI method but not in men with either evaluation method. In the longitudinal dataset, both a slight decline and increase over time were seen in DAT uptake; however, a general pattern of decrease was seen in both men and women in D2R uptake. The choice of the image evaluation method can influence the pattern of sex-based and age-related differences. The results speak for the use of age-stratified reference values for women, in particular when using a VOI method.

Periprosthetic Bone Turnover after Primary Total Hip Arthroplasty Measured by Single-Photon Emission Computed Tomography

Alterations in periprosthetic bone are common sequlae of prosthetic implants.This prospective 3-year study was performed to follow regional periprosthetic bone turnover after uncomplicated total hip arthroplasty (THA) using single-photon emission computed tomography (SPECT). Eighteen patients (nine men, nine women: mean age 61 years, range from 50 to 73 years) with primary hip osteoarthritis underwent either uncemented or cemented THA. The SPECT measurements were taken 6, 12, and 36 months after THA. Bone mineral density (BMD) measurements were performed on the patients during follow-up. The mean SPECT uptake ratios decreased significantly in the regions of interest (ROIs) during follow-up compared to baseline value, in the trochanter major (p = 0.006), the trochanter minor (p = 0.009) and the total area (p = 0.018). Despite these decreases the uptake ratios in the medial cortex (p = 0.014), tip (p = 0.002) and total area (p = 0.016) remained significantly higher in the operated side than in the contralateral side (non-operated) 3 years after THA. Changes in bone turnover in the vicinity of the implant did not correlate with changes in periprosthetic BMD. Local periprosthetic bone turnover decreased slowly after THA and did not recover to the level typical of non-operated hips. This led us to suggest that bone turnover around the femoral implants remains increased more than 3 years after THA even if there are no signs of failure of the prosthesis.

Correlation of glioma proliferation assessed by flow cytometry with 99mTc-Tetrofosmin SPECT uptake

Objectives Brain single-photon emission computed tomography (SPECT) has been proposed as a potentially useful modality for the metabolic assessment of various brain tumors. Material and methods In a 10-patient prospective pilot study we evaluated whether 99mTc-Tetrofosmin ( 99mTc-TF) uptake correlates with glioma proliferative activity assessed by flow cytometric analysis. 99mTc-TF brain SPECT was performed shortly before surgical tumor excision. Results Eight patients were diagnosed with glioblastoma multiform and 2 with anaplastic astrocytoma. All tumors were aneuploid. We found a significant positive linear correlation between 99mTc-TF uptake and percentage of tumor cells on the S-phase of the cell cycle ( r = 0.92, P = 0.001). Conclusion Initial evidence suggests that 99mTc-TF could provide a non-invasive indicator of glioma proliferative activity.

SU-FF-J-136: The Impact of Attenuation and Scatter Correction On the SPECT Guided Radiation Therapy for Lung Cancer Patients: Comparison of SPECT Weighted Mean Dose and Functional Lung Segmentation

Purpose: To investigate the impact of different types of image reconstruction and attenuation/scatter (A/S) correction on the calculation of dosimetric indices proposed to be used for Single Photon Emission Computed Tomography (SPECT) guided dose escalation in lung cancer patients. Methods and Materials: SPECT lung perfusion scans were obtained for nine lung cancer patients using 99mTc-macroaggregated albumin. Four image sets were reconstructed from each scan: one using a vendor provided ordered subsets expectation maximization (OSEM) algorithm, two quantitative SPECT reconstructions using OSEM methods with different types of A/S corrections and the fourth an OSEM reconstruction without any A/S correction. SPECT weighted mean dose (SWMD), dose function histogram, and functional lung volume have been calculated from dose distributions and regional perfusion maps. To investigate the dependence of SWMDs on gantry angle, twelve equally spaced co-planar open field radiation beams delivering the same MU were centered on the PTV. Three field sizes, 5×5, 7.5×7.5 and 10×10cm2 were considered. SWMDs were calculated for each field and reconstruction. Functional lung volumes were segmented in each reconstruction using 10, 20, …, 90% of maximum SPECT uptake as a threshold. Results: SWMDs calculated from reconstructions without A/S correction showed more than 5% average difference compared to those with corrections. With A/S corrections, more consistent SWMDs were found in all the three OSEM reconstructions (average difference ∼2%). However, a large variation was observed between segmented functional lung volumes and the V20 of these volumes in all four reconstructions. The difference between the volumes reached over 50% regardless of whether A/S correction was applied in the reconstruction. Conclusion: Functional volume segmentation is sensitive to the type of A/S correction. In contrast, SPECT weighted mean dose calculation produces more consistent results and appears to be a more robust choice for clinical outcome analysis and SPECT guided treatment planning.

Is there Still Enough Diagnostic Confidence with Bone Spect Scintigraphy Alone: A Retrospective Evaluation and Extended Review of the Literature

Aim: Single photon emission computed tomography (SPECT) dramatically increases the sensitivity of bone scanning for detection of spinal abnormalities. However, the level of specificity obtained by SPECT remains controversial and increased diagnostic confidence can be obtained with new imaging modalities such as fused PET/CT and SPECT/CT. Patients and Methods: Between 7/2005 and 7/2007 ninety one patients with different malignant primary tumors were in- vestigated. Following injection of 555 MBq 99m Tc - MDP planar and SPECT images were performed in all patients. Re- sults: Out of a total of 145 spinal lesions was confirmed by radiography, SPECT detected 133 (91%). In contrast, planar scintigraphy detected only 99/145 (68%) lesions. SPECT uptake pattern including the vertebral body and an adjacent pedicle was seen in 9/28 (32%) of metastatic lesions and in 1/2 (50%) cases of spondylitis. SPECT uptake pattern includ- ing the pedicle alone was seen in 45/115 (39%) of degenerative alterations. Focal lesions limited to the lateral part of the vertebral body, especially to the pars interarticularis (n=8), facet joints (n=14) and costotransversal joints (n=6), were cor- rectly diagnosed as spondylarthrosis and costotransversalarthrosis in all cases. Furthermore, SPECT uptake pattern of spondylitis was biconcave, whereas metastatic lesions showed focal or linear uptakes. Conclusion: SPECT without image fusion still gives sufficient diagnostic confidence for the differentiation of benign and malignant spine lesions. Uptake pat- terns localized at the facet joints or localized at the pedicles are indicative for benign lesions, whereas continuous uptake patterns of the vertebral body and adjacent pedicle remain suspicious for malignancy.

Bone mineral density and single photon emission computed tomography changes after total knee arthroplasty: a 2‐year follow‐up study

Dual X-ray absorptionmetry (DXA) provides a highly reproducible method for quantitative analysis and monitoring periprosthetic bone mineral density (BMD) after total knee arthroplasty (TKA). Single photon emission computed tomography (SPECT) with bone avid radiopharmaceuticals reflects bone metabolic activity and circulation. We combined information from DXA and SPECT to assess the evaluation of the dynamic balance between BMD and bone turnover. Sixteen patients underwent serial DXA (Lunar Expert XL) and 99mTc-methylene diphosphonate SPECT measurements until 2 years after TKA. A rapid bone loss, up to 25.5%, was detected in femur during the first six postoperative months. However, tibial periprosthetic BMD remained close to baseline. There was a significant correlation between 12-month SPECT uptake and preceding BMD change in medial tibia (r = 0.5, P = 0.044). At 12 months, SPECT uptakes in the operated knee were notably higher compared with those of the control knee. SPECT uptakes showed statistically significant decreases from 12 months to 24 months, while SPECT uptake in the control knee remained stable. In tibia, the results are more complex; referring that increased bone remodelling is continuing below the tibial tray. Furthermore, femoral diaphyseal uptake remained elevated, while corresponding tibial uptake had levelled off at 2 years. Increased SPECT uptake during the first 2 years after uncomplicated TKA results most likely from normal postoperative bone remodelling. Levelling of SPECT uptake may indicate a new balance between bone loss and regain.

Low Back Pain in Pediatric Athletes With Unilateral Tracer Uptake at the Pars Interarticularis on Single Photon Emission Computed Tomography

Retrospective clinical study with radiographic and medical chart review. To study the clinical characteristics and outcome of pediatric athletes with low back pain and unilateral tracer uptake on single photon emission computed tomography (SPECT) at the pars interarticularis but no defect on radiographs. Some pediatric athletes with low back pain have no findings on plain radiographs but a unilateral SPECT uptake at the pars interarticularis. However, little is known about these patients. Twenty-two pediatric athletes who had low back pain with increased tracer uptake on SPECT unilaterally at the pars interarticularis but no defect on plain radiograph were evaluated. The following criteria were used for evaluation: age, male-to-female ratio, duration of symptoms, vertebral level, and presence of spina bifida occulta or scoliosis. The average age was 12.3 +/- 2.5 years. The male-to-female ratio was 1.2:1. The average duration of symptoms was 21 +/- 23 weeks. Nineteen (86%) had increased uptake at L5. Six (27%) had spina bifida occulta and 8 (36%) had scoliosis. Eighteen (82%) patients showed an excellent outcome. The patients who presented with a longer history of symptoms or a concomitant spina bifida occulta had an increased risk of having occasional aching with vigorous activity when compared with the patients who did not (P < 0.05). Athletes who have low back pain and increased tracer uptake unilaterally at the pars interarticularis on SPECT are younger than those previously reported patients with spondylolysis proven by a defect on radiographs. Some of these lesions do progress to "frank" spondylolysis seen on radiographs, but favorable clinical outcomes from nonoperative treatment can be expected. Patients with a longer pain history or concomitant spina bifida occulta may need careful follow-up because they are at increased risk of having occasional low back pain.

Voxel-wise analysis of [123I]β-CIT SPECT differentiates the Parkinson variant of multiple system atrophy from idiopathic Parkinson's disease

To investigate the cerebral dopamine transporter status in the early stages of the parkinson-variant of multiple system atrophy (MSA-P), 15 patients with MSA-P and a disease duration up to 3 years were studied with [123I]beta-CIT single photon emission computed tomography (SPECT). Data were compared with 13 age-matched healthy control subjects and 15 patients with idiopathic Parkinson's disease (IPD), matched for age and disease duration. Parametric SPECT images of the specific-to-nondisplaceable equilibrium partition coefficient (V3''), which is proportional to the receptor density (Bmax) have been generated. To objectively localize focal changes in dopaminergic function throughout the entire brain volume without having to make an a priori hypothesis as to their location, statistical parametric mapping (SPM) was applied to our [123I]beta-CIT SPECT study. Both MSA-P and IPD patients showed significant decreases in striatal [123I]beta-CIT SPECT uptake. However, in MSA-P patients an additional reduction in midbrain [123I]beta-CIT signal was localized with SPM compared with control subjects (MSA-P, V3'': 0.89 +/- 0.37 versus controls V3'': 1.81 +/- 0.38; P < 0.001) and patients with IPD (V3'': 1.84 +/- 0.26; P < 0.001). Stepwise linear discriminant analysis of mean [123I]beta-CIT uptake in the putamen, caudate and midbrain identified the caudate and midbrain as indices to classify correctly 95.2% of subjects as either normal, patients with MSA-P or IPD. Voxel-wise analysis of [123I]beta-CIT SPECT revealed more widespread decline of monoaminergic transporter availability in MSA-P compared with IPD, matching the underlying pathological features. We suggest that the quantification of midbrain DAT signal should be included in the routine clinical analysis of [123I]beta-CIT SPECT in patients with uncertain parkinsonism.

123I]AM281 single-photon emission computed tomography imaging of central cannabinoid CB 1 receptors before and after Δ 9-tetrahydrocannabinol therapy and whole-body scanning for assessment of radiation dose in tourette patients

Background The cannabinoid CB 1 receptor agonist Δ 9-THC has been suggested for treatment of Tourette syndrome (TS). Based on animal studies, the CB 1 antagonist [ 123I]AM281 (N-(Morpholin-4-yl)-1-(2,4-dichlorophenyl)-5-(4-[ 123I]iodophenyl)-4-methyl-1H-pyrazole-3-carboxamide) has been proposed for single photon emission computed tomography (SPECT) in humans. Our aims were to 1) evaluate specific binding of [ 123I]AM281 to CB 1 receptors in TS patients and 2) assess radiation exposure associated with the use of AM281 labeled with 123I for SPECT and 124I for positron emission tomography. Methods We employed [ 123I]AM281 in six TS patients before and after Δ 9-THC treatment. Dynamic SPECT, plasma measurements (including metabolite analysis with thin layer chromatography), and whole-body imaging were performed. Regions of interest derived from magnetic resonance images were used to extract from SPECT uptake in an area with high CB 1 density (lentiform nuclei) and reference regions. Specific over nonspecific partition coefficients V 3′′ were calculated. Whole-body images were carried out for dosimetric analysis. Data obtained with [ 123I]AM281 were used to predict doses from [ 124I]AM281. Results Mean V 3′′ ranged from .19 to .31 and did not change significantly after Δ 9-THC treatment. Nevertheless, in the only patient with a marked clinical response, V 3′′ clearly declined. Thin layer chromatography revealed biexponential kinetics of tracer metabolism; about 60% remained nonmetabolized after 3 hours. Effective doses of .011 mSv/MBq for [ 123I]AM281 and .34 for [ 124I]AM281 were computed. Conclusions This study suggests that specific binding of [ 123I]AM281 to CB 1 receptors can be detected in patients using SPECT. Radiation exposure with [ 123I]AM281 is low; that with [ 124I]AM281 is higher but acceptable for single investigations.

Comparison of real-time coherent contrast imaging to dipyridamole thallium-201 single-photon emission computed tomography for assessment of myocardial perfusion and left ventricular wall motion

Real-time coherent contrast imaging (CCI) echocardiography has the ability to evaluate wall motion and myocardial perfusion simultaneously, but its clinical applicability in the diagnosis of coronary artery disease (CAD) remains to be determined. This study examines the level of agreement between real-time CCI echocardiography and thallium-201 single-photon emission computed tomography (SPECT) following stress vasodilation. Forty-two patients with known or suspected CAD underwent real-time CCI using octafluoropropane-filled microspheres infusion before and after dipyridamole and thallium-201 injections. The apical 4- and 2-chamber views were each divided into 6 segments to assess wall motion and perfusion. Real-time CCI and SPECT were interpreted independently. Thirty-eight patients successfully completed tests, and 4 had suboptimal contrast images. Each vascular territory was classified as normal or abnormal by CCI perfusion, wall motion, and SPECT at baseline and at stress. Of the 114 territories (3 in each of the 38 patients), 3 (3.5%) were not analyzed; however, all territories corresponding to the left anterior descending artery were suitable for analysis. Concordance between CCI echocardiography and thallium-201 SPECT perfusion for left anterior descending, left circumflex, and right coronary artery territories were 91%, 86%, and 69%, respectively; between CCI perfusion and wall motion, the correlations were 93%, 93%, and 91%, respectively. When CCI perfusion and wall motion analysis were combined, their concordance to thallium-201 SPECT uptake improved to 94%, 89%, and 79%, respectively. In conclusion, real-time CCI echocardiography agrees very closely with thallium-201 SPECT in assessing myocardial perfusion following vasodilatory stress. Assessment of myocardial perfusion, in addition to segmental wall motion analysis, during stress echocardiography may be a significant contribution to the noninvasive evaluation of patients with ischemic heart disease.

Errata

In vivo imaging of the dopamine transporter (DAT) with single photon emission computed tomography (SPECT) is a quantitative biomarker for Parkinson's disease (PD) onset and severity. This study has examined and compared the loss of striatal DAT in PD and multiple system atrophy (MSA) using [123I]β-CIT SPECT imaging. One hundred and eighty-three patients (157 PD and 26 MSA) were studied. Clinical rating scales (Hoehn and Yahr stage and Unified Parkinson's Disease Rating Scale [UPDRS] scores) demonstrated that the MSA patients were more severely impaired than the PD patients. The striatal [123I]β-CIT SPECT uptake was markedly reduced in both the PD and MSA groups. In addition, MSA patients showed more symmetric DAT loss compared with the PD patients, consistent with the more symmetric clinical motor dysfunction observed in MSA. While the loss of DAT was significantly reduced in all regions in both MSA and PD, comparison of the relative loss of the DAT did not significantly improve diagnostic accuracy in distinguishing between PD and MSA. © 2001 Movement Disorder Society.

Single‐Photon Emission Computed Tomography of the Brain in Acute Mania and Schizophrenia

Single-photon emission computed tomography (SPECT) imaging with n-isopropyliodoamphetamine (IMP) was performed on 11 patients with bipolar mania, 21 acute schizophrenics, and 15 healthy control subjects. Subjects were evaluated with neuropsychological tests and psychiatric rating scales. SPECT brain studies were blindly evaluated to assess the degree of radiopharmaceutical uptake in three neuroanatomical regions of interest in each hemisphere. All the control subjects, 1 manic patient, and 1 schizophrenic patient had normal brain SPECT uptake patterns. The scans of all others were read as abnormal. Hypofrontality was noted in some schizophrenics and maniacs. A significant increase in tracer uptake in temporal lobes was observed in both patient groups, more prominently in the manic patients. Increased and decreased basal ganglia uptake was also observed in patients. Both manic and schizophrenic patients showed cortical tracer heterogeneity of varying degree. The patterns of cerebral SPECT uptake seen in these acute psychoses were not specific for a diagnosis, but may be associated with dimensions of psychopathology. Because the patterns are different from those seen in cerebrovascular disease and the dementias, they may prove to be helpful in differential diagnosis.