Single Photon Emission Computed Tomography Scans Research Articles

Changes in Regional Cerebral Blood Flow of A Depressed Patient Before and During Musical Hallucinations: A Case Report

Musical hallucinations (MHs) are a type of auditory hallucination in which music is perceived despite a lack of actual sound. Few reports have described longitudinal neuroimaging findings in different conditions before and during MHs. This report describes a depressed patient whose regional cerebral blood flow (rCBF) was assessed using single-photon emission computed tomography (SPECT) before and during MHs. A 72-year-old depressed woman was admitted to our hospital. During the treatment period, she experienced MHs. Then MHs disappeared with treatment of depression or following improvement in the mood. SPECT scans were performed to assess the levels of rCBF in several brain areas before and during MHs. During MHs, rCBF was increased in the basal ganglia, thalamus, amygdala, and parietal lobes. This report suggests that increased rCBF in multiple brain areas, especially in the basal ganglia and thalamus, might be related to the pathophysiology of MHs in depressed patients.

Precision radiotherapy by SPECT lung functional imaging in NSCLC

Background: Single Photon Emission Computed Tomography (SPECT) could be used to avoid the non-affected perfusion areas in patients with non-small-cell lung cancer (NSCLC) and to potentially reduce lung toxicity. The aim of this study is to compare dosimetric differences between two different 3D-conformal treatment plans, with and without CT/SPECT contribution. Methods: Simulation Computed tomography (CT) scans were accurately co-registered with SPECT scans and three different areas, based on SPECT intensity perfusion, were contoured: low perfusion (LP), medium perfusion (MP) and high perfusion (HP). Two different 3D-conformal plans, with co-planar and nonco-planar fields, were generated; one without SPECT information (anatomic plan), and one using the perfusion area identified with functional imaging (functional plan). Results: 9 patients were planned and a total of 18 plans were available for analysis. Anatomical and functional plans resulted in comparable planning target volume (PTV) coverage. In the functional plans, a significant reduction of dose in high perfusion areas was reported. The reduction of HP-V20 Gy values ranged from 15% to 8% (p = 0.046), the ipsiHP-V20 Gy from 38% to 22% (p = 0.028) and ipsiHP-Dmean reduction from 16 Gy to 12 Gy (p = 0.039). No significant differences in other organs at risk (OARs) metrics were reported between anatomical and functional plans. Conclusions: Despite the few cases reported, the strength of our study lies in the reported benefit of functional lung information in 3D conformal radiation planning, without compromising target coverage or worsening dose distribution to the OARs. There is an urgent need for prospective clinical and randomized trials in order to define the role of lung functional imaging in reducing toxicity in clinical practice.

Performance Evaluation of a Preclinical SPECT Scanner with a Collimator Designed for Medium-Sized Animals.

Background Equipped with two stationary detectors, a large bore collimator for medium-sized animals has been recently introduced for dedicated preclinical single-photon emission computed tomography (SPECT) imaging. We aimed to evaluate the basic performance of the system using phantoms and healthy rabbits. Methods A general-purpose medium-sized animal (GP-MSA) collimator with 135 mm bore diameter and thirty-three holes of 2.5 mm diameter was installed on an ultrahigh-resolution scanner equipped with two large stationary detectors (U-SPECT5-E/CT). The sensitivity and uniformity were investigated using a point source and a cylinder phantom containing 99mTc-pertechnetate, respectively. Uniformity (in %) was derived using volumes of interest (VOIs) on images of the cylinder phantom and calculated as [(maximum count − minimum count)/(maximum count + minimum count) × 100], with lower values of % indicating superior performance. The spatial resolution and contrast-to-noise ratios (CNRs) were evaluated with images of a hot-rod Derenzo phantom using different activity concentrations. Feasibility of in vivo SPECT imaging was finally confirmed by rabbit imaging with the most commonly used clinical myocardial perfusion SPECT agent [99mTc]Tc-sestamibi (dynamic acquisition with a scan time of 5 min). Results In the performance evaluation, a sensitivity of 790 cps/MBq, a spatial resolution with the hot-rod phantom of 2.5 mm, and a uniformity of 39.2% were achieved. The CNRs of the rod size 2.5 mm were 1.37, 1.24, 1.20, and 0.85 for activity concentration of 29.2, 1.0, 0.5, and 0.1 MBq/mL, respectively. Dynamic SPECT imaging in rabbits allowed to visualize most of the thorax and to generate time-activity curves of the left myocardial wall and ventricular cavity. Conclusion Preclinical U-SPECT5-E/CT equipped with a large bore collimator demonstrated adequate sensitivity and resolution for in vivo rabbit imaging. Along with its unique features of SPECT molecular functional imaging is a superior collimator technology that is applicable to medium-sized animal models and thus may promote translational research for diagnostic purposes and development of novel therapeutics.

New Radionuclides and Technological Advances in SPECT and PET Scanners.

Simple SummaryAdvances in nuclear medicine are made by technological and radionuclide improvements. Throughout nuclear medicine’s history, these advances were often intertwined and complementary based on different clinical questions, availability and need. This paper covers some of these developments in radionuclides and instrumentation.Developments throughout the history of nuclear medicine have involved improvements in both instrumentation and radionuclides, which have been intertwined. Instrumentation developments always occurred during the search to improving devices’ sensitivity and included advances in detector technology (with the introduction of cadmium zinc telluride and digital Positron Emission Tomography—PET-devices with silicon photomultipliers), design (total body PET) and configuration (ring-shaped, Single-Photon Emission Computed Tomography (SPECT), Compton camera). In the field of radionuclide development, we observed the continual changing of clinically used radionuclides, which is sometimes influenced by instrumentation technology but also driven by availability, patient safety and clinical questions. Some areas, such as tumour imaging, have faced challenges when changing radionuclides based on availability, when this produced undesirable clinical findings with the introduction of unclear focal uptakes and unspecific uptakes. On the other end of spectrum, further developments of PET technology have seen a resurgence in its use in nuclear cardiology, with rubidium-82 from strontium-82/rubidium-82 generators being the radionuclide of choice, moving away from SPECT nuclides thallium-201 and technetium-99m. These continuing improvements in both instrumentation and radionuclide development have helped the growth of nuclear medicine and its importance in the ever-evolving range of patient care options.

Non‐fluent/agrammatic variant of primary progressive aphasia with progressive supranuclear palsy

AbstractBackgroundNon‐fluent/agrammatic variante of primary progressive aphasia (nfvPPA) is a neurodegenerative disorder characterized by speech production impairment (1). The overlap of nfvPPA and progressive supranuclear palsy (PSP) and corticobasal syndrome cases have been reported (2). As nfvPPA progresses, a parkinsonian disorder often co‐occurs (3). There are different kinds of language impairment including articulatory deficits, agrammatism, reduced speech rate, and anomia (1). Here we present a Peruvian woman with nfvPPA with single‐photon emission computed tomography (SPECT) and parkinsonian syndrome.MethodWe describe a 73‐year‐old woman with progressive speech production impairment and parkinsonian syndrome. She completed standard neurological, neuropsychological, and speech‐language evaluations, as well as brain MRI and SPECT scan.ResultThe patient is a right‐handed woman with 16 years of education. No family history of dementia, parkinsonism or motor neuron disease was reported. At age 71, she presented progressive difficulty in speaking, anomia and verbal hesitancy; but she can understand conversations, send and read text messages. She also had depressive symptoms. MRI showed mild left frontal and perisylvian > right atrophy (fig 1).By age 73, she developed a prominent reduction in spontaneous speech, mild difficulties in reading and writing, occasional paraphasia, less empathy, dietary change, moria and, mild parkinsonism (she expresses less emotion, tremor, slowly walk and falls). Her episodic memory starts to decline thereafter.On examination, she had mild‐moderate telegraphic speech, imitation behavior, mild facial masking, bradykinesia and mild postural instability but no abnormal extraocular movement. Speech‐language assessment showed non‐fluent aphasia and apraxia of speech. Impaired comprehension of syntactically complex sentences. Naming was mildly impaired. Syntactic errors were present. Executive function was also impaired, but visuoperceptual skills were preserved.Serological analyses were unrevealing. Brain SPECT scan showed left frontal and perisylvian > right cortical hypoperfusion (fig 2).ConclusionWe report a Peruvian case of an elderly woman presenting with a 3‐year history of nfvPPA features and PSP. Her SPECT scan showed left frontal and perisylvian > right cortical hypoperfusion. Consider early evaluating motor function in nfvPPA patients in light of the possibility of CBS or PSP overlap.

SPECT Functional Neuroimaging Distinguishes Adult Attention Deficit Hyperactivity Disorder From Healthy Controls in Big Data Imaging Cohorts.

Background: The diagnosis of attention deficit hyperactivity disorder (ADHD) relies on history and observation, as no reliable biomarkers have been identified. In this study, we compared a large single diagnosis group of patients with ADHD (combined, inattentive, and hyperactive) to healthy controls using brain perfusion single-photon emission computed tomography (SPECT) imaging to determine specific brain regions which could serve as potential biomarkers to reliably distinguish ADHD.Methods: In a retrospective analysis, subjects (n = 1,135) were obtained from a large multisite psychiatric database, where resting state (baseline) and on-task SPECT scans were obtained. Only baseline scans were analyzed in the present study. Subjects were separated into two groups – Group 1 (n = 1,006) was composed of patients who only met criteria for ADHD with no comorbid diagnoses, while a control group (n = 129) composed of individuals who did not meet criteria for any psychiatric diagnosis, brain injury, or substance use served as a non-matched control. SPECT regions of interests (ROIs) and visual readings were analyzed using binary logistic regression. Predicted probabilities from this analysis were inputted into a Receiver Operating Characteristic analysis to identify sensitivity, specificity, and accuracy.Results: The baseline ROIs and visual readings show significant separations from healthy controls. Sensitivity of the visual reads was 100% while specificity was >97%. The sensitivity and specificity of the post-hoc ROI analysis were both 100%. Decreased perfusion was primarily seen in the orbitofrontal cortices, anterior cingulate gyri, areas of the prefrontal cortices, basal ganglia, and temporal lobes. In addition, ROI analysis revealed some unexpected areas with predictive value in distinguishing ADHD, such as cerebellar subregions and portions of the temporal lobes.Conclusions: Brain perfusion SPECT distinguishes adult ADHD patients without comorbidities from healthy controls. Areas which were highly significantly different from control and thus may serve as biomarkers in baseline SPECT scans included: medial anterior prefrontal cortex, left anterior temporal lobe, and right insular cortex. Future studies of these potential biomarkers in ADHD patients with comorbidities are warranted.

EEG Driven Autonomous Injection System For An Epileptic Neuroimaging Application.

Seizure episodes are frequently observed for adults and children suffering from medically refractory epilepsy and the events remain debilitating unless treated with a more comprehensive approach. Ictal perfusion studies with single-photon emission computed tomography (SPECT) is one of the non invasive imaging modality that has been extensively used to adequately localize the seizure focus. Current practices include the tracer injection within a short time interval at the onset of seizure to generate desirable SPECT scan quality with accurate information on foci region. However, the onset of a seizure is a highly unpredictable event and also with added subclinical events, the overall procedure makes it difficult to administer the tracer manually within the ideal time frame.Hence a complete autonomous injection of radioactive tracer element without manual intervention is expected to offer a highly accurate epileptical focus region and aids in further management of the patient. Electroencephalogram (EEG) physiological signals in the preictal phase contain sufficient indicators to predict the seizure event. The proposed injection system works on the seizure prediction model from the EEG signals to release the dosage, making the system completely autonomous in action. The accuracy of the prediction model based on the publicly available seizure embedded EEG datasets was designed to achieve 94% accuracy, and the model was deployed on an edge system. The syringe based injection system was characterized to emulate dosage release action with minimum volumetric error, and low injection time, on predicting seizure Ictal event from the EEG signal. The proposed system is a step towards developing an autonomous injection system for epileptic neuroimaging applications in hospital settings.Clinical relevance- Autonomous injection of tracer dosage for obtaining accurate and high quality Ictal SPECT scan results is preferred over the manual operation in clinical and hospital residential settings as a part of pre-surgical evaluations. The EEG signal based early prediction of seizure ensures adequate time for radioactive tracer element to reach the brain cells and eventually helps to accurately localize the onset region of seizure in the brain. The EEG driven automated injection system for the noninvasive Ictal SPECT method is clinically important as a pre-surgical evaluation in MRI negative or discordant cases for further surgical actions.

Diagnostic performance of CMR, SPECT, and PET imaging for the detection of cardiac amyloidosis: a meta-analysis

BackgroundNoninvasive myocardial imaging modalities, such as cardiac magnetic resonance (CMR), single photon emission computed tomography (SPECT), and Positron emission tomography (PET), are well-established and extensively used to detect cardiac amyloid (CA). The purpose of this study is to directly compare CMR, SPECT, and PET scans in the diagnosis of CA, and to provide evidence for further scientific research and clinical decision-making.MethodsPubMed, Embase, and Cochrane Library were searched. Studies used CMR, SPECT and/or PET for the diagnosis of CA were included. Pooled sensitivity, specificity, positive and negative likelihood ratio (LR), diagnostic odds ratio (DOR), their respective 95% confidence intervals (CIs) and the area under the summary receiver operating characteristic (SROC) curve (AUC) were calculated. Quality assessment of included studies was conducted.ResultsA total of 31 articles were identified for inclusion in this meta-analysis. The pooled sensitivities of CMR, SPECT and PET were 0.84, 0.98 and 0.78, respectively. Their respective overall specificities were 0.87, 0.92 and 0.95. Subgroup analysis demonstrated that 99mTc-HMDP manifested the highest sensitivity (0.99). 99mTc-PYP had the highest specificity (0.95). The AUC values of 99mTc-DPD, 99mTc-PYP, 99mTc-HMDP were 0.89, 0.99, and 0.99, respectively. PET scan with 11C-PIB demonstrated a pooled sensitivity of 0.91 and specificity of 0.97 with an AUC value of 0.98.ConclusionOur meta-analysis reveals that SEPCT scans present better diagnostic performance for the identification of CA as compared with other two modalities.

Quantification of SPECT with <sup>99m</sup>Tc-technetryl and of contrast-enhanced MRI scans in survival prognosis of patients with glial brain tumors after combined chemo – radiation treatment

Purpose of study. The possibility of simultaneous and combined use of magnetic resonance imaging (MRI) with paramagnetic contrast enhancement (CE-MRI) and single-photon emission computed tomography (SPECT) with 99mTc-MIBI in assessing the prognosis in patients with glial brain tumors after complex chemo – and radiotherapy treatment was studied.Material and methods. Contrast-enhanced MRI of the brain and SPECT with 99mTc-Technetril were performed in 19 patients who were observed after complex chemoradiotherapy of brain tumors (gliomas of grade 3 and 4). The treatment included remote gamma irradiation and chemotherapy with temozolomide. The radiation dose was 60 Gy (30 fractions of 2 Gy × 1 once a day). The drug Temodal was prescribed in a single dose of 75 mg/sq. m. (120–140 mg) an hour before gamma therapy for up to 40 days (in a total dose of 5000–5900 mg) and in the post – radiation period according to the scheme – 6 courses of the drug for 5 days every 23 days in a single dose of 200 mg/sq.m. (280–400 mg). The total dose of Temodal for 1 course was 1400–2000 mg. In everybody, after the study, the time period of subsequent survival of patients was registered from to the primary health care data.Results. The survival time was over 20 months in case of patients after surgical removal of glial tumor and with subsequent adjuvant chemotherapy if simultaneous low values of “Tumor-to Normal Tissue” index for both 99mTc-Technetryl SPECT and CE-MRI were met, i.e. if < 1,15 for 99mTc-Technetryl SPECT and < 1,19 for CE-MRI. If index “Tumor-to Normal Tissue” was over > 1,25 99mTc-Technetryl SPECT and > 1,35 for CE-MRI then the survival time was below one year. If the “Tumor-to Normal Tissue”ratio on 99mTc-Technetryl SPECT scan was in benefit ranges whereas the on CE-MRI kept itself in high pathologic ranges the survival time was also over 19 months.Conclusion. Thus, the concomitant quantification and fusion of uptake of 99mTc-Technetryl and paramagnetic contrast agents on SPECT and MRI scans provides prognostic data on survival of patients and is worth routine use for therapy control.

Image-Guided Right T10 Costotransverse Joint Resection for Costotransversitis: Operative Technique and Nuances: 2-Dimensional Operative Video

We describe the operative approach and management for costotransverse joint inflammation in a 49-yr-old man with worsening midthoracic pain radiating to the right paraspinal area. He underwent physical therapy with no relief of his symptoms. Thoracic spine magnetic resonance imaging (MRI) revealed severe arthritic changes involving the right T10 costotransverse joint. Scoliosis X-rays showed a dextroconvex curvature in the midthoracic spine, without any significant imbalance. Single-photon emission computed tomography (SPECT) scan revealed focal increased uptake of the right T10 costotransverse joint. T10 costotransverse joint lidocaine injection did not provide any relief. We performed a computed tomography (CT)-guided biopsy, which was negative for malignancy and also cultures were negative. MRI revealed a significant enhancement in this area and the patient's C-reactive Protein was elevated. Decision was made to perform open biopsy and costotransverse joint resection. We present a case of minimally invasive, image-guided costotransverse joint resection, which has not been described in the literature. The right T10 costotransverse joint was dissected out with the image-guided dilator, and tubular retractors were inserted. Under the microscope, using the image-guided drill, the right T10 costotransverse joint was drilled out. The lateral aspect of the right T10 process was drilled out as well as the medial-dorsal aspect of the right T10 rib. The patient recovered from surgery well with abatement of his preoperative thoracic pain, which remained abated at 6-mo follow-up. This case highlights the complex technical nuances of this procedure, and the importance of a thorough preoperative evaluation with a bone SPECT scan to help localize the pain generator. Patient consented for the procedures and for the publication of the video.

Idiopathic Moyamoya Disease Presenting as Isolated Hemichorea

AbstractThe study aimed to describe a case of a 7-year-old Caucasian girl who developed isolated chorea in her right upper and lower extremities progressively increasing over 2 years. This study is a case report and conducted at tertiary care center. A 7-year-old Caucasian girl who gradually developed worsening choreiform movements in her right upper and lower extremities over the course of 2 years until medical attention was sought. Literature review of children presenting with chorea as the only manifestation in moyamoya disease. A 7-year-old right-handed Caucasian girl presented with progressively worsening choreiform movements in her right upper and lower extremities affecting her fine motor skills and gait impairment There was no weakness, hyperreflexia, or spasticity on her neurological exam. Neuroimaging studies showed “ivy sign,” asymmetric prominence of vessels within the subarachnoid spaces overlying the left cerebral hemisphere with corresponding serpiginous T2 fluid-attenuated inversion recovery abnormality, but no parenchymal volume loss or diffusion restriction. Magnetic resonance angiography showed focal moderate-to-severe stenosis at the junction of the paraophthalmic and supraclinoid segments of the left internal carotid artery, with poststenotic dilatation. Angiography demonstrated focal stenosis involving the ophthalmic segment of the left internal carotid artery with 50% stenosis. There was compensation through a medium sized left posterior communicating artery as well as posterior cerebral artery to middle cerebral artery and anterior cerebral artery collateralization. Brain single-photon emission computerized tomography scan showed no evidence of perfusion defects in the cerebral hemispheres, basal ganglia, or thalami. She underwent successful revascularization procedure (left pial synangiosis) with resolution of her choreiform movements and normalization of her gait. Our case demonstrates that moyamoya disease should be suspected when evaluating a child with hemichorea and describes resolution of symptoms after revascularization surgery. Neuroimaging and vascular studies should be obtained in children with unilateral movement disorder.

Adaptation of Melodic Intonation Therapy to Greek: A Clinical Study in Broca's Aphasia With Brain Perfusion SPECT Validation.

Melodic intonation therapy (MIT) is one of the most well-known treatment methods which is based on pitch and rhythm and was developed to increase verbal output in adults with non-fluent aphasia. Although MIT has been adapted to several languages, in Greece it is almost unknown. The aim of the proposed study is twofold: (1) to translate and adapt the MIT to the Greek language, and (2) to conduct an experimental study in order to examine the effect of MIT on Greek patients with Broca’s aphasia. To this aim, a 64-year-old, right-handed male who had a 6-year primary school education level, no musical abilities and poor performance on the recognition of prosody attended the MIT intervention program almost two and a half years after the event of suffering an ischemic stroke. The MIT intervention was administered three times per week for a 12-week period, in which each session lasted from 30 to 40 min. The patient underwent three assessments all using both the Boston Diagnostic Aphasia Examination–Short Form (BDAE-SF) and brain perfusion single-photon emission computed tomography (SPECT); (1) before the MIT, (2) immediately after, and (3) 3 months after the completion of MIT. The results from the BDAE-SF revealed an impressive improvement on both trained and prepositional speech production, immediately after the completion of the MIT, and a stable improved performance 3 months after MIT. The SPECT scan revealed reactivation of the perilesional areas of the left hemisphere, and considerably improved perfusion of the frontal lobe, the anterior temporal lobe, and the upper part of the parietal lobe of the right hemisphere. The improvement persisted and even expanded 3 months after MIT. Therefore, MIT is a promising intervention program and its positive effects last for at least 3 months after the completion of the intervention.

A novel supervised machine learning algorithm to detect Parkinson’s disease on its early stages

Early and accurate Parkinson’s disease (PD) diagnosis are usually complex as clinical symptoms often onset only when there is extensive loss of dopaminergic neurons in substantia-nigra and symptoms are atypical at an early stages of the disease. Recent brain imaging modality such as single photon emission computed tomography (SPECT) with 123I- Ioflupane (DaTSCAN) have shown to be a better diagnostic tool for PD even in its initial stages. Presently machine learning algorithms have become trendier and play important role to automate PD diagnosis and predict its progression. In machine learning community, support vector regression (SVR) has recently received much attention due to its ability to negotiate between fitting accuracy and model complexity in training prediction models. This work presents an optimized SVR with weights associated to each of the sample data to automate PD diagnosis and predict its progression at primary stages. The proposed algorithm (W-SVR) is trained with motor and cognitive symptom scores in addition to striatal binding ratio (SBR) values calculated from the 123I-Ioflupane SPECT scans (taken from the Parkinson’s progression markers initiative (PPMI) database) for early PD prognosis accurately. In model building, different kernels are used to check the accuracy and goodness of fit. We observed promising results obtained by W-SVR in comparison with classic Support vector regression.

Self-Collimating SPECT With Multi-Layer Interspaced Mosaic Detectors.

Conventional single photon emission computed tomography (SPECT) relies on mechanical collimation whose resolution and sensitivity are interdependent, the best performance a SPECT system can attain is only a compromise of these two equally desired properties. To simultaneously achieve high resolution and sensitivity, we propose to use sensitive detectors constructed in a multi-layer in ter spaced mosaicdetectors (MATRICES) architecture to accomplish part of the collimation needed. We name this new approach self-collimation. We evaluate three self-collimating SPECT systems and report their imaging performance: 1) A simulated human brain SPECT achieves 3.88% sensitivity, it clearly resolves 0.5-mm and 1.0-mm hot-rod patterns at noise-free and realistic count-levels, respectively; 2) a simulated mouse SPECT achieves 1.25% sensitivity, it clearly resolves 50- [Formula: see text] and 100- [Formula: see text] hot-rod patterns at noise-free and realistic count-levels, respectively; 3) a SPECT prototype achieves 0.14% sensitivity and clearly separates 0.3-mm-diameter point sources of which the center-to-center neighbor distance is also 0.3 mm. Simulated contrast phantom studies show excellent resolution and signal-to-noise performance. The unprecedented system performance demonstrated by these 3 SPECT scanners is a clear manifestation of the superiority of the self-collimating approach over conventional mechanical collimation. It represents a potential paradigm shift in SPECT technology development.

The effect of injection time on rates of epileptogenic zone localization using SISCOM and STATISCOM

BackgroundThe identification of hyperperfusion on ictal single-photon emission computed tomography (SPECT) scan is a technique for the localization of the epileptogenic zone (EZ) in patients with focal epilepsy undergoing presurgical evaluation. The accuracy of this technique has been improved by subtraction from an interictal image and coregistration with magnetic resonance imaging (MRI) (subtraction ictal SPECT coregistered to MRI (SISCOM)), and subsequently by the development of Statistical Ictal SPECT Co-registered to MRI (STATISCOM) which is reported to further improve localization accuracy by statistically accounting for random variation between images. However, the use of ictal SPECT is limited by the necessity for rapid injection of the radiotracer. The purpose of this study was to investigate the effect of tracer injection time on EZ localization rates using both STATISCOM and SISCOM. MethodsConsecutive patients with drug-resistant focal epilepsy who had an ictal SPECT scan while admitted to the video-electroencephalography (EEG) monitoring unit at the Royal Melbourne Hospital, Victoria, Australia, and a subsequent interictal scan, between 2009 and 2017 were included. The information collected included age, sex, seizure type, epilepsy diagnosis, and injection time. Statistical Ictal SPECT Co-registered to MRI and SISCOM images were generated and reviewed by two blinded reviewers. The rates of potential localization of the EZ, and the agreement with the EEG, were determined for each scan. Localization rates were compared between ictal scans with different radiotracer injection time windows (<30 s, 30–45 s, 45–60 s, 60–90 s, 90–120 s, >120 s). ResultsSeventy patients (male = 32, 16–67 years) were included in the study. Overall agreement between the primary raters was moderate for STATISCOM (k = 0.44) and SISCOM (k = 0.57). The ability of SPECT to localize the potential EZ was 69% (48/70) for STATISCOM and 59% (41/70) for SISCOM. Injection time was not associated with the rate of localizing the potential EZ for STATISCOM (p = 0.64), whereas for SISCOM there was a trend that shorter injection times were associated with better ability to localize the potential EZ (p = 0.06).Agreement between SPECT and video-EEG data was 54% (38/70) for STATISCOM and 39% (27/70) for SISCOM. Statistical Ictal SPECT Co-registered to MRI did not show any difference of agreement across injection time groups (p = 0.42) whereas SISCOM showed better agreement with video-EEG data in the earlier injection time groups (p = 0.02). No differences in agreement between SPECT and video-EEG data were seen between patients with and without MRI lesions for either STATISCOM or SISCOM. Statistical Ictal SPECT Co-registered to MRI showed significantly better agreement for temporal than extratemporal seizures, with no difference of agreement between early (<45 s) and late (>45 s) injections. ConclusionStatistical Ictal SPECT Co-registered to MRI showed overall higher agreement rates with EZ localization by video-EEG than SISCOM, which was not affected by the injection times. Statistical Ictal SPECT Co-registered to MRI may provide localizing information for “late” injections where visual reads and SISCOM are inconclusive.

Electron microscopy of antibody-conjugated, lutetium-177 lanthanide gold-coated nanoparticles: Proof of concept of targeted loci—A potential theranostic agent

Following murine injection, the ultrastructural loci of nanoparticles (NPs) containing lutetium-177 (Lu-177) conjugated to an anti-thrombomodulin antibody (mAb-201b) were determined. The results confirmed prior work localizing NPs using Single Photon Emission Computed Tomography (SPECT) scans. The in vivo pharmacokinetics of these NPs were also identified. mAb-201b antibodies are primarily attracted to the thrombomodulin, a membrane protein in the endothelium of the lung vasculature. SPECT images demonstrated NPs in the lungs, liver, spleen, and proximal small bowel. Prior injection of clodronate liposomes reduced the number of circulating macrophages, which, in turn, reduced NP phagocytosis. At 24 h after injection of NPs and after final SPECT imaging, the lungs, liver, spleen, and kidneys were harvested for transmission electron microscopy. Although some NPs were found in all four organs, 85% of the injected dose was localized in type I and type II pneumocytes. Small concentrations were found in secondary lysosomes in hepatocytes, in splenic macrophages, and in an intravascular macrophage in a kidney. Importantly, there was no apoptosis or necrosis in any of the tissues, highlighting the relative safety of the radionuclide NP, whose primary interaction with non-targeted organs/tissues is in the filtration process. In addition to validating the biodistribution results of the SPECT scans carried out in our prior work, this study is proof of principle that NPs conjugated with appropriate antibodies can target specific antigens in vivo. From a theranostic perspective, these results suggest that radioactive nanoconjugates labeled with proper antigens should be able to target and destroy a variety of cancers with minimal harm to the surrounding healthy cells.

Added diagnostic value of SPECT to evaluate bone metastases inbreast cancer patients with normal whole body bone scan.

Background:In this research, we aimed to survey the added value of single photon emission computed tomography (SPECT) in comparison with planar whole body bone scan to visualize bone metastatic lesions in patients with breast cancer.Methods:A total of 80 patients with breast cancer (invasive ductal carcinoma) were examined with planar whole body bone scan and SPECT imaging using 99mTc-labelled methylene diphosphonate (99mTc-MDP). The patients with abnormal uptakes in SPECT imaging were also investigated with magnetic resonance imaging (MRI).Results:Among these 80 patients with normal whole body bone SPECT scan, 19 (23.25%) of them revealed abnormal 99mTc-MDP uptake in skeleton. Furthermore, these 19 patients were subjected to MRI and 3 (3.75%) of them were confirmed with metastatic bone lesion.Conclusion:The obtained data suggest that SPECT possess the added diagnostic over planar whole body bone scan.

Evaluation of a variable-aperture full-ring SPECT system using large-area pixelated CZT modules: A simulation study for brain SPECT applications.

Single photon emission computed tomography (SPECT) scanners using cadmium zinc telluride (CZT) offer compact, lightweight, and improved imaging capability over conventional NaI(Tl)-based SPECT scanners. The main purpose in this study is to propose a full-ring SPECT system design with eight large-area CZT detectors that can be used for a broad spectrum of SPECT radiopharmaceuticals and demonstrate the performance of our system in comparison to the reference conventional NaI(Tl)-based two-head Anger cameras. A newly designed full-ring SPECT system is composed of eight large-area CZT cameras (128mm×179.2mm effective area) that can be independently swiveled around their own axes of rotation independently and can have radial motion for varying aperture sizes that can be adapted to different sizes of imaging volume. Extended projection data were generated by conjoining projections of two adjacent detectors to overcome the limited field-of-view (FOV) by each CZT camera. Using Monte Carlo simulations, we evaluated this new system design with digital phantoms including a Derenzo hot rod phantom and a Zubal brain phantom. Comparison of performance metrics such as spatial resolution, sensitivity, contrast-to-noise ratio (CNR), and contrast-recovery ratio was made between our design and conventional SPECT scanners having different pixel sizes and radii of rotation (one clinically well-known type and two arbitrary types matched to our proposed CZT-SPECT geometries). The proposed scanner could result in up to about three times faster in acquisition time over conventional scan time at same acquisition time per step. The spatial resolution improvement, or deterioration, of our proposed scanner compared to the clinical-type scanner was dependent upon the location of the point source. However, there were overall performance improvements over the three different setups of the conventional scanner particularly in volume sensitivity (approximately up to 1.7 times). Overall, we successfully reconstructed the phantom image for both 99m Tc-based perfusion and 123 I-based dopamine transporter (DaT) brain studies simulated for our new design. In particular, the striatal/background contrast-recovery ratio in 3-to-1 reference ratio was over 0.8 for the 123 I-based DaT study. We proposed a variable-aperture full-ring SPECT system using combined pixelated CZT and energy-optimized parallel-hole collimator modules and evaluated the performance of this scanner using relevant digital phantoms and MC simulations. Our studies demonstrated the potential of our new full-ring CZT-SPECT design, showing reduced acquisition time and improved sensitivity with acceptable CNR and spatial resolution.

A Novel Hyperspectral Imaging System for Intraoperative Prediction of Cerebral Hyperperfusion Syndrome after Superficial Temporal Artery-Middle Cerebral Artery Anastomosis in Patients with Moyamoya Disease

Background: Postoperative cerebral hyperperfusion syndrome (CHS) may occur after superficial temporal artery (STA)-middle cerebral artery (MCA) bypass for moyamoya disease (MMD). Predicting postoperative CHS is challenging; however, we previously reported the feasibility of using a hyperspectral camera (HSC) for monitoring intraoperative changes in brain surface hemodynamics during STA-MCA bypass. Objective: To investigate the utility of HSC to predict postoperative CHS during STA-MCA bypass for patients with MMD. Methods: Hyperspectral images of the cerebral cortex of 29 patients with MMD who underwent STA-MCA bypass were acquired by using an HSC before and after anastomosis. We then analyzed the changes in oxygen saturation after anastomosis and assessed its correlation with CHS. Results: Five patients experienced transient neurological deterioration several days after surgery. ¹²³I-N-Isopropyl-iodoamphetamine single-photon emission computed tomography scan results revealed an intense, focal increase in cerebral blood flow at the site of anastomosis without any cerebral infarction. Patients with CHS showed significantly increased oxygen saturation (SO₂) in the cerebral cortex after anastomosis relative to those without CHS (33 ± 28 vs. 8 ± 14%, p < 0.0001). Receiver operating characteristic analysis results show that postoperative CHS likely occurs when the increase rate of cortical SO₂ value is >15% (sensitivity, 85.0%; specificity, 81.3%; area under curve, 0.871). Conclusions: This study indicates that hyperspectral imaging of the cerebral cortex may be used to predict postoperative CHS in patients with MMD undergoing STA-MCA bypass.

A physics and learning-based transmission-less attenuation compensation method for SPECT.

Attenuation compensation (AC) is a pre-requisite for reliable quantification and beneficial for visual interpretation tasks in single-photon emission computed tomography (SPECT). Typical AC methods require the availability of an attenuation map, which is obtained using a transmission scan, such as a CT scan. This has several disadvantages such as increased radiation dose, higher costs, and possible misalignment between SPECT and CT scans. Also, often a CT scan is unavailable. In this context, we and others are showing that scattered photons in SPECT contain information to estimate the attenuation distribution. To exploit this observation, we propose a physics and learning-based method that uses the SPECT emission data in the photopeak and scatter windows to perform transmission-less AC in SPECT. The proposed method uses data acquired in the scatter window to reconstruct an initial estimate of the attenuation map using a physics-based approach. A convolutional neural network is then trained to segment this initial estimate into different regions. Pre-defined attenuation coefficients are assigned to these regions, yielding the reconstructed attenuation map, which is then used to reconstruct the activity distribution using an ordered subsets expectation maximization (OSEM)-based reconstruction approach. We objectively evaluated the performance of this method using highly realistic simulation studies conducted on the clinically relevant task of detecting perfusion defects in myocardial perfusion SPECT. Our results showed no statistically significant differences between the performance achieved using the proposed method and that with the true attenuation maps. Visually, the images reconstructed using the proposed method looked similar to those with the true attenuation map. Overall, these results provide evidence of the capability of the proposed method to perform transmission-less AC and motivate further evaluation.