Single Photon Emission Computed Tomography Findings Research Articles

Identifying and troubleshooting the pitfalls of ictal/interictal brain perfusion SPECT studies.

Epilepsy is a prevalent condition, and surgical intervention can benefit patients with refractory seizures. Single photon emission computed tomography (SPECT) using 99mTc-HMPAO or 99mTc-ECD provides assessment of regional cerebral blood flow and is the primary non-invasive approach for imaging brain perfusion in ictal and interictal states. Ictal/interictal SPECT is valuable in localising epileptogenic foci, particularly when MRI and electroencephalography are negative. However, to obtain accurate images reflecting brain perfusion in both states, meticulous preparation of the patient, timely radiotracer injection and close coordination between neurology and nuclear medicine teams are essential. Tracers also have inherent limitations, and patients may present with coexisting brain pathologies for which coregistration of SPECT images with MRI is recommended to improve diagnostic accuracy. Inconclusive SPECT findings may require repeating the exam or considering additional investigations. A comprehensive approach, considering various factors, is crucial for accurate interpretation of SPECT studies in presurgical epilepsy evaluations. This article provides a summary of the organisation and key challenges involved in conducting ictal/interictal SPECT studies, covering the entire process from a patient's hospital arrival to the integration of results within their presurgical pathway and using our experience of 182 patients over 10 years.

Hyperbaric Oxygen Therapy for the Management of Mild and Moderate Traumatic Brain Injury: A Single-Center Experience

Hyperbaric oxygen therapy (HBOT) has been shown to be an effective modality in the management of a variety of conditions. However, its role in the treatment of traumatic brain injury (TBI) remains an area of controversy. This study aims to evaluate the safety and outcomes of HBOT in managing the long-term sequelae of TBI. The records of TBI patients who underwent increments of 40 sessions of HBOT at 1.5 atmosphere absolute at a single medical center were reviewed. The outcome measures included physical, cognitive (i.e., Trail Making Test, parts A and B; U.S. Department of Veterans Affairs' Evaluation of Cognitive Impairment and Subjective Symptoms tool), and single-photon emission computed tomography findings. The complications and withdrawals were recorded. During the study period, 17 patients underwent HBOT to manage the long-term sequelae of their TBI. Of the 17 patients, 12 (70.6%) completed 120 HBOT sessions and were evaluated 3 months after treatment. All 12 patients had statistically significant improvements in their Trail Making Test, parts A and B, and U.S. Department of Veterans Affairs' Evaluation of Cognitive Impairment and Subjective Symptoms scores (P < 0.05). Additionally, single-photon emission computed tomography depicted increased cerebral blood flow and oxygen metabolism among studied subjects compared with the baseline values. A total of 5 patients withdrew from the study, which was related to new-onset headaches associated with HBOT for 1 patient. HBOT using 1.5 atmosphere absolute in increments of 40 sessions was found to be a safe and effective modality in the management of the long-term sequelae of TBI. HBOT should be considered in the management of this patient population.

A Pilot Study on Cerebral Blood Flow and Mini-Mental State Examination to Predict Amyloid Deposition in Preclinical Alzheimer's Disease.

Earlier differential diagnosis of dementia remains a major challenge. Although amyloid deposition by positron emission tomography is an emerging standard for the diagnosis of Alzheimer's disease, it is too expensive for routine use in clinical settings. We conducted a pilot study on the potential usefulness of single-photon emission computed tomography and the Mini-Mental State Examination to predict amyloid positron emission tomography positivity in preclinical Alzheimer's disease. Eighteen subjects, including 11 with mild cognitive impairment and 7 with subjective cognitive decline, underwent 18F-florbetapir positron emission tomography, 99mTc-ethylcysteinate dimer cerebral perfusion single-photon emission computed tomography, and the Mini-Mental State Examination. For the assessment of amyloid deposition, visual judgment as a qualitative method and a semiautomatic software analysis as a quantitative method were used. Six subjects were judged as amyloid positive, including 4 mild cognitive impairment and 2 subjective cognitive decline subjects. Compared to the amyloid positron emission tomography-negative group, this group showed a statistically significant difference in the Mini-Mental State Examination recall score [2 (1 : 3) vs. 3 (2 : 3), P = .041] and single-photon emission computed tomography findings from the amyloid-negative group. In the mild cognitive impairment subgroup, correlations were found between amyloid deposition and single-photon emission computed tomography indicators, while in the subjective cognitive decline subgroup, only the Mini-Mental State Examination recall score correlated with amyloid deposition. The Mini-Mental State Examination recall score and single-photon emission computed tomography indicators may be worthwhile for further evaluation as predictors of amyloid deposition in the preclinical stage.

The diagnostic value of ictal SPECT-A retrospective, semiquantitative monocenter study.

Ictal single photon emission computed tomography (SPECT) can be used as an advanced diagnostic modality to detect the seizure onset zone in the presurgical evaluation of people with epilepsy. In addition to visual assessment (VSA) of ictal and interictal SPECT images, postprocessing methods such as ictal-interictal SPECT analysis using SPM (ISAS) can visualize regional ictal blood flow differences. We aimed to evaluate and differentiate the diagnostic value of VSA and ISAS in the Bonn cohort. We included 161 people with epilepsy who underwent presurgical evaluation at the University Hospital Bonn between 2008 and 2020 and received ictal and interictal SPECT and ISAS. We retrospectively assigned SPECT findings to one of five categories according to their degree of concordance with the clinical focus hypothesis. Seizure onset zones could be identified more likely on a sublobar concordance level by ISAS than by VSA (31% vs. 19% of cases; OR=1.88; 95% Cl [1.04, 3.42]; P=0.03). Both VSA and ISAS more often localized a temporal seizure onset zone than an extratemporal one. Neither VSA nor ISAS findings were predicted by the latency between seizure onset and tracer injection (P=0.75). In people who underwent successful epilepsy surgery, VSA and ISAS indicated the correct resection site in 54% of individuals, while MRI and EEG showed the correct resection localization in 96% and 33% of individuals, respectively. It was more likely to become seizure-free after epilepsy surgery if ISAS or VSA had been successful. There was no MR-negative case with successful surgery, indicating that ictal SPECT is more useful for confirmation than for localization. The results of the most extensive clinical study of ictal SPECT to date allow an assessment of the diagnostic value of this elaborate examination and emphasize the importance of postprocessing routines.

The Emerging Role of SPECT Functional Neuroimaging in Schizophrenia and Depression.

Over the last three decades, the brain's functional and structural imaging has become more prevalent in psychiatric research and clinical application. A substantial amount of psychiatric research is based on neuroimaging studies that aim to illuminate neural mechanisms underlying psychiatric disorders. Single-photon emission computed tomography (SPECT) is one of those developing brain imaging techniques among various neuroimaging technologies. Compared to PET, SPECT imaging is easy, less expensive, and practical for radioligand use. Current technologies increased the spatial accuracy of SPECT findings by combining the functional SPECT images with CT images. The radioligands bind to receptors such as 5-hydroxytryptamine 2A, and dopamine transporters can help us comprehend neural mechanisms of psychiatric disorders based on neurochemicals. This mini-review focuses on the SPECT-based neuroimaging approach to psychiatric disorders such as schizophrenia and major depressive disorder (MDD). Research-based SPECT findings of psychiatric disorders indicate that there are notable changes in biochemical components in certain disorders. Even though many studies support that SPECT can be used in psychiatric clinical practice, we still only use subjective diagnostic criteria such as the Diagnostic Statistical Manual of Mental Disorders (DSM-5). Glimpsing into the brain's biochemical world via SPECT in psychiatric disorders provides more information about the pathophysiology and future implication of neuroimaging techniques.

Discrepancy Between the Degree of Cognitive Impairment and Brain Imaging Abnormalities in Alzheimer's Disease Patients Is Associated with Cognitive Reserve.

In Alzheimer's disease (AD) patients, the severity of cognitive impairment is thought to correlate with the degree of brain imaging abnormalities. However, some patients show only mild cognitive deficit, despite severe brain atrophy on magnetic resonance imaging (MRI) or marked hypoperfusion in the cerebral cortices on single-photon emission computed tomography (SPECT). This suggests that cognitive reserve (CR) can compensate for the clinical manifestations of AD in patients with extensive brain pathology. We aimed to determine whether this discrepancy between cognitive and imaging findings is associated with CR. Factors associated with the discrepancy between the degree of cognitive impairment and MRI (medial temporal lobe atrophy) and SPECT (posterior cerebral hypoperfusion) findings were analyzed in 135 patients with probable AD. Factors as proxies for CR included education, occupation, leisure activity, comorbidities, frailty, and other demographics. The discrepancy index (DI) was calculated as the difference between the degree of imaging abnormalities and the degree of cognitive dysfunction. Multiple regression analysis showed that leisure activity and education were significantly associated with the discrepancy between cognitive and imaging findings. When the level of CR was determined based on leisure activity and education, the high-CR group showed a significantly larger DI than the moderate- and low-CR groups. The discrepancy between cognitive and imaging findings in patients with AD is associated with CR, measured using a combination of two indicators, i.e., leisure activity and education. Therefore, lifestyle interventions may delay the appearance of clinical symptoms resulting from underlying AD pathology, by increasing CR.

Effect of different parietal hypoperfusion on neuropsychological characteristics in mild cognitive impairment.

In early-stage amnestic mild cognitive impairment (aMCI), differences in the neuropsychological characteristics of each individual are subtle. We investigated differences in neuropsychological performance between aMCI patients with and without hypoperfusion in the medial parietal regions (MP). We further compared patients with hypoperfusion in the left and right lateral parietal regions. We examined 165 aMCI patients (mean age: 76.8 ± 5.5 years; 87 women) who had undergone neuropsychological measurement and single-photon emission computed tomography. We classified participants into two subgroups with and without hypoperfusion: MP hypoperfusion (+) and MP hypoperfusion (-); classification was based on Z-scores (calculated by three-dimensional stereotactic surface projection technique) of three regions of interest in the parietal lobes (i.e. MP regions including posterior cingulate cortex and precuneus and left and right inferior parietal lobules (lateral parietal regions)). The MP hypoperfusion (-) group was classified into left lateral parietal hypoperfusion (+) and right lateral parietal hypoperfusion (+) subgroups. We performed either univariate or multivariate ancova to compare neuropsychological scores for continuous variables between groups and examined dichotomous variables using χ2 tests. In the overall aMCI sample, scores on logical memory delayed recall in the MP hypoperfusion (+) group were significantly lower than those in the MP hypoperfusion (-) group. Total scores on Rey-Osterrieth Complex Figure Test delayed recall were also marginally lower in the MP hypoperfusion (+) group than in the MP hypoperfusion (-) group. Comparisons of neuropsychological test scores between the left and right lateral parietal hypoperfusion (+) groups revealed no significant differences. The present findings suggest that MP hypoperfusion (+) is associated with more robust memory deficits than MP hypoperfusion (-). Combining neuropsychological tests and single-photon emission computed tomography findings may be useful for early detection of cognitive decline in aMCI.

Quantitative evaluation of single-photon emission computed tomography findings in lower extremity possible without computed tomography-based attenuation correction.

For performing accurate quantitative analysis of single-photon emission computed tomography (SPECT)/computed tomography (CT) images, CT-based attenuation correction (CTAC) is considered to be necessary. However, the effect on quantitative values for an examined area close to the body surface, such as in the lower extremity, has yet to be elucidated. We performed the present investigation to determine the possibility of quantitative evaluation using a SPECT standalone device without CT. Validation was performed using clinical data of patients who underwent a lower extremity SPECT/CT examination, with grouping based on presence or absence of CTAC, scatter correction and resolution recovery. Using a reference group in which all types of correction were applied, standardized uptake values (SUVs), including maximum (SUVmax) and peak (SUVpeak), were examined in each group and compared. As compared to the reference group, the difference in quantitative values became smaller in the order of the applied scatter correction and resolution recovery, applied resolution recovery, applied scatter correction, and neither scatter correction or resolution recovery applied groups, with no significant difference between the reference group and that with neither scatter correction or resolution recovery applied. A similar tendency was seen for both SUVmax and SUVpeak. In bone SPECT quantitative examinations of the lower extremity, quantitative evaluation without CTAC is possible without the use of scatter correction or resolution recovery. Thus, quantitative evaluation can be performed with use of a standalone SPECT device without CT.

Comparative contribution of magnetoencephalography (MEG) and single-photon emission computed tomography (SPECT) in pre-operative localization for epilepsy surgery: A prospective blinded study

PurposeThe aim of this study was to compare the diagnostic value and accuracy of ictal SPECT and inter-ictal magnetoencephalography (MEG) in localizing the site for surgery in persons with drug resistant epilepsy. MethodThis was a prospective observational study. Patients expected to undergo epilepsy surgery were enrolled consecutively and the localization results from different imaging modalities were discussed in an epilepsy surgery meet. Odds ratio of good outcome (Engel I) were calculated in patients who underwent surgery in concordance with MEG and SPECT findings. Post-surgical seizure freedom lasting at least 36 months or more was considered the gold standard for determining the diagnostic output of SPECT and MEG. ResultsMEG and SPECT were performed in 101 and 57 patients respectively. In 45 patients SPECT could not be done due to delay in injection or technical factors. The accuracy of MEG and SPECT in localizing the epileptogenic zone was found to be 74.26 % and 78.57 % respectively. The diagnostic odds ratio for Engel I surgical outcome was reported as 2.43 and 5.0 for MEG and SPECT respectively. The diagnostic odds ratio for MEG in whom SPECT was non-informative was found to be 6.57 [95 % CI 1.1, 39.24], although it was not significantly associated with good surgical outcome. MEG was useful in indicating sites for SEEG implantation. ConclusionSPECT was found to be non-informative for most patients, but reported better diagnostic output than MEG. MEG may be a useful alternative for patients in whom SPECT cannot be done or was non-localizing.

Molecular imaging of schizophrenia: Neurochemical findings in a heterogeneous and evolving disorder

The past four decades have seen enormous efforts placed on a search for molecular markers of schizophrenia using positron emission tomography (PET) and single photon emission computed tomography (SPECT). In this narrative review, we cast a broad net to define and summarize what researchers have learned about schizophrenia from molecular imaging studies. Some PET studies of brain energy metabolism with the glucose analogue FDGhave have shown a hypofrontality defect in patients with schizophrenia, but more generally indicate a loss of metabolic coherence between different brain regions. An early finding of significantly increased striatal trapping of the dopamine synthesis tracer FDOPA has survived a meta-analysis of many replications, but the increase is not pathognomonic of the disorder, since one half of patients have entirely normal dopamine synthesis capacity. Similarly, competition SPECT studies show greater basal and amphetamine-evoked dopamine occupancy at post-synaptic dopamine D2/3 receptors in patients with schizophrenia, but the difference is likewise not pathognomonic. We thus propose that molecular imaging studies of brain dopamine indicate neurochemical heterogeneity within the diagnostic entity of schizophrenia. Occupancy studies have established the relevant target engagement by antipsychotic medications at dopamine D2/3 receptors in living brain. There is evidence for elevated frontal cortical dopamine D1 receptors, especially in relation to cognitive deficits in schizophrenia. There is a general lack of consistent findings of abnormalities in serotonin markers, but some evidence for decreased levels of nicotinic receptors in patients. There are sparse and somewhat inconsistent findings of reduced binding of muscarinic, glutamate, and opioid receptors ligands, inconsistent findings of microglial activation, and very recently, evidence of globally reduced levels of synaptic proteins in brain of patients. One study reports a decline in histone acetylase binding that is confined to the dorsolateral prefrontal cortex. In most contexts, the phase of the disease and effects of past or present medication can obscure or confound PET and SPECT findings in schizophrenia.

METABOLIC SINGLE-PHOTON EMISSION COMPUTED TOMOGRAPHY WITH THE NEW RADIOPHARMACEUTICAL ⁹⁹ᵐTc-1-thio-D-glucose IN THE DIAGNOSIS AND MONITORING OF THE PRIMARY BREAST LYMPHOMA (CASE REPORT)

The article shows the feasibility of detecting and monitoring primary breast diffuse large B-cell lymphoma using single-photon emission computed tomography (SPECT) with 99mTc-1-thio-D-glucose (99mТс-TG), a new radiopharmaceutical. The innovative radiopharmaceutical makes it possible to evaluate the metabolism of tumor tissue without using positron emission tomography. The findings of 99mTc-TG SPECT obtained during diagnosis and monitoring of the patient were confirmed by the results of computed tomography. A comprehensive examination of the patient, including 99mTc-TG SPECT, made it possible to diagnose a rare case of primary breast lymphoma. Primary breast lymphoma accounts for 1.7–2.2 % of all extranodal nonHodgkin lymphomas. Diffuse large B-cell lymphoma is the most common histological type occurring usually as a unilateral palpable tumor in middle-aged women. Extranodal lymphomas account for less than 0.5 % of all malignant neoplasms of the breast. After 6 courses of immunochemotherapy, the patient underwent 99mTc-TG SPECT, which demonstrated persistent hypermetabolic activity in the breast. The patient received radiation therapy to the remaining tumor of the left breast. The patient is in remission and followed up at the Cancer Research Institute of Tomsk National Research Medical Center. Thus, 99mTc-TG SPECT is believed to be a promising method for visualizing primary breast lymphomas and assessing their treatment outcomes. It is an alternative to the standard approach using 18F-FDG positron emission tomography. The method compares favorably with positron emission tomography with its wide availability and low cost of study.

Does Tc-99m ECD ictal brain SPECT have incremental value in localization of epileptogenic zone and predicting postoperative seizure freedom in cases with discordant video electroencephalogram and MRI findings?

Localization of epileptogenic focus in drug-refractory epilepsy using Tc-99m ethylene cystine dimer (ECD) brain single photon emission computed tomography (SPECT) is less studied in patients with discordant findings on video electroencephalogram (VEEG) and MRI. The study was done to evaluate brain SPECT for epileptogenic focus localization and postoperative seizure freedom. Epilepsy patients with discordant VEEG and MRI findings underwent brain SPECT at ictal and interictal phases. Various groups unilateral/bilateral mesial temporal sclerosis (MTS), solitary and multifocal lesional, nonlesional epilepsy were studied for localization of epileptogenic focus and postoperative seizure freedom (>2 years) using Engels classification. Reasons for nonoperability was evaluated in nonoperated group. SPECT could localize epileptogenic focus in 49/67 (73.13%) and guided surgery in 19/33 (57.57%) patients in operated group. SPECT was useful in 12 (46.12%) of unilateral (2)/bilateral (10) MTS. Postoperative seizure freedom of Engels Class I and II in 22 (66.67%), III in six (18.2%) and IV in one patient based on SPECT findings (P = 0.0086). Overall sensitivity and specificity were 79.3% and 85.7%, respectively. SPECT could localize epileptogenic focus in 23/34 (67.64%) patients in nonoperated group; 10 (29.41%) patients refused for surgery and no epileptogenic focus was localized in the rest of 14 (41.2%). Ictal SPECT showed incremental value and was found necessary for epileptogenic focus localization and subsequent surgery in unilateral/bilateral MTS in this study. Seizure freedom in patients undergoing epilepsy surgery based on ictal SPECT assistance was comparable to the surgical group not requiring ictal SPECT.

The value of myocardial perfusion imaging in screening coronary artery disease before kidney transplantation.

The value of myocardial single-photon emission computed tomography (SPECT) in pre-transplant evaluation of kidney transplant recipients is controversial. We assessed whether myocardial SPECT predicts major adverse cardiac events (MACE) and determined whether SPECT findings affected transplant recipients' medical and invasive treatment. We analyzed 301 patients referred for myocardial SPECT before kidney transplantation and combined the results with information from patient files and the Transplantation Registry. During the median follow-up time of 96months (IQR 70.75-118.25months), the incidence of MACE was higher in patients (n=37) with severely abnormal SPECT (>10% reversible perfusion defect) than in patients (n=35) with mildly abnormal or normal SPECT (51.4%, 29.4%, and 27.0%, respectively, P=.011). Severely abnormal SPECT findings predicted long-term MACE in a univariable analysis but not after adjusting for other risk factors. Following SPECT, 29 patients (9.6%) underwent coronary angiography and 14 (4.6%) were revascularized. New antithrombotic or statin medication was prescribed to 7.3% of patients with ischemia in SPECT. Kidney transplantation patients are at high long-term risk of MACE even with normal preoperative myocardial SPECT. Abnormal SPECT did not predict MACE when adjusted for other risk factors. Minority of the patients underwent coronary revascularization or had changes in preventive medication before transplantation.

123I-FP-CIT SPECT validation of nigro-putaminal MRI tractography in dementia with Lewy bodies

BackgroundAssessment of nigrostriatal degeneration is a key element to discriminate between dementia with Lewy bodies (DLB) and Alzheimer disease (AD), and it is often evaluated using ioflupane (123I-FP-CIT) single-photon emission computed tomography (SPECT). Given the limited availability of 123I-FP-CIT SPECT, we evaluated if a mask-based approach to nigroputaminal magnetic resonance imaging (MRI) diffusion-weighted tractography could be able to capture microstructural changes reflecting nigroputaminal degeneration in DLB.MethodsA nigroputaminal bundle mask was delineated on 12 healthy volunteers (HV) and applied to MRI diffusion-weighted data of 18 subjects with DLB, 21 subjects with AD and another group of 12 HV. The correlation between nigroputaminal fractional anisotropy (FA) values and 123I-FP-CIT SPECT findings was investigated. Shapiro-Wilk, ANOVA, ANCOVA, and parametric correlation statistics as well as receiver operating characteristic (ROC) analysis were used.ResultsDLB patients showed a higher nigroputaminal FA values compared with both AD and HV-controls groups (p = 0.001 for both comparisons), while no difference was observed between HV-controls and AD groups (p = 0.450); at ROC analysis, the area under the curve for the discriminating DLB and AD subjects was 0.820; FA values correlated with 123I-FP-CIT values (on the left, r = -0.670; on the right, r = -720). No significant differences were observed for the FA of the corticospinal tract across the three groups (p = 0.740).ConclusionsIn DLB, nigroputaminal degeneration could be reliably assessed on MRI diffusion scans using a mask of nigroputaminal bundle trajectory. Nigroputaminal FA in DLB patients correlated with 123I-FP-CIT values data may allow to differentiate these patients from AD patients and HV-controls.

Crossed cerebellar diaschisis as an indicator of severe cerebral hyperperfusion after direct bypass for moyamoya disease.

Cerebral hyperperfusion (HP) complicates the postoperative course of patients with moyamoya disease (MMD) after direct revascularization surgery. Crossed cerebellar diaschisis (CCD) has been considered to be rarely associated with HP after revascularization surgery. This study aimed to describe the clinical features and factors associated with CCD secondary to cerebral HP after revascularization surgery for MMD. We analyzed 150 consecutive hemispheres including 101 in adults and 49 in pediatric patients who underwent combined direct and indirect bypass for MMD. Using single-photon emission computed tomography (SPECT), serial cerebral blood flow (CBF) was measured immediately after the surgery and on postoperative days 2 and 7. Pre- and postoperative voxel-based analysis of SPECT findings was performed to compare the changes in regional CBF. Multivariate logistic regression analysis was performed to test the effect of multiple variables on CCD. Asymptomatic and symptomatic HP was observed in 41.3% (62/150) and 16.7% (25/150) of the operated hemispheres, respectively. CCD was observed in 18.4% (16/87) of these hemispheres with radiological HP. Multivariate analysis revealed that the occurrence of CCD was significantly associated with symptomatic HP (p = 0.0015). Voxel-based analysis showed that the CBF increase in the operated frontal cortex, and the CBF reduction in the contralateral cerebellar hemisphere on day 7 were significantly larger in symptomatic HP than in asymptomatic HP (median 11.3% vs 7.5%; - 6.0% vs - 1.7%, respectively). CCD secondary to postoperative HP is more common than anticipated in MMD. CCD could potentially be used as an indicator of severe postoperative HP in patients with MMD.

Does SPECT Provide Incremental Value to CT or MRI in Assessing Mandibular Invasion by Oral Squamous Cell Carcinoma?

Single photon emission computed tomography (SPECT) has been commonly used as an additional method to assess mandibular bone invasion in patients with oral squamous cell carcinoma (OSCC). In the present study, we measured the diagnostic validity of SPECT findings compared with the histologic findings. We implemented a retrospective cross-sectional study and enrolled a sample of patients with OSCC adjacent to the mandible. The staging examinations included magnetic resonance imaging (MRI) and/or computed tomography (CT) and additional SPECT. The patients' medical records and imaging data were reviewed by 2 readers, and bone invasion was classified as positive or negative for each diagnostic method. The predictor was bone invasion found on CT and/or MRI compared with the combination of CT and/or MRI with either positive or negative SPECT results. The primary outcome variable was histologic bone invasion. Other variables of interest were clinicopathologic data, type of mandibular resection, and resection margin status. Bivariate tests were used to compare the diagnostic specificity, sensitivity, and accuracy of each imaging modality. The study enrolled 122 patients, with a mean age of 67years (55% male; study period, January 2010 to December 2017). In 60 patients (49%), segmental mandibular resection was performed. The sensitivity and specificity for bone invasion were 100% and 39% for SPECT and 84% and 75% for CT and/or MRI. The negative results for bone invasion using SPECT did not match the false-positive CT and/or MRI results in 5% (n=6 of 122). Positive SPECT findings, in addition to positive CT and/or MRI findings increased the sensitivity to 100% but decreased the specificity to 29% (P<.001). Considering only negative SPECT findings increased the specificity to 85% (P=.03), sensitivity remaining unaffected. The accuracy of CT and/or MRI alone was 80% and was 84% when combining CT and/or MRI and negative SPECT findings (P=.03). In oncologic staging with CT and/or MRI, the addition of SPECT provided only small benefits. Only negative SPECT results allowed for greater specificity and accuracy. The use of SPECT could be considered to rule out bone invasion in cases of radiologic uncertainty of positive CT or MRI findings.

Assessing cardiovascular risk in the prerenal transplant population: Comparison of myocardial perfusion imaging and coronary angiography with risk factor stratification.

Patients with end-stage renal disease (ESRD) have a higher incidence of coronary artery disease (CAD). Hence, it is crucial to evaluate CAD before renal transplantation. This study compares the utility of pharmacologic single-photon emission computed-tomography (SPECT) imaging directly to coronary angiography for diagnosis of CAD with correlation to cardiovascular risk factors. Retrospective review of asymptomatic renal failure patients who underwent both SPECT and coronary angiography to identify obstructive CAD between the years 2008-2016. Ninety-four ESRD subjects were evaluated. Myocardial perfusion SPECT study found, when compared to coronary angiography demonstrated for CAD, the sensitivity of 93.3% with a specificity of 73.4%. Importantly, the negative predictive value for coronary artery disease was 96%. With seven or more cardiac risk factors, 66.7% of patients had obstructive coronary artery disease. Among all the risk factors examined, patients with a previous history of coronary artery disease had a 68% risk of obstructive coronary artery disease. Comparing myocardial perfusion imaging SPECT findings with coronary angiography in patients with ESRD, a sensitivity of 93.3% and a specificity of 73% were observed. Of all the risk factors examined, patient with the previous history of CAD was the single most significant risk factor for CAD in 68% of cases.

Reversal of the reversed ‘Robin Hood syndrome’ after superficial temporal-Middle cerebral artery bypass for severe intracranial stenosis

Background: Intracranial arterial stenosis is a common cause of ischemic stroke. Recent attempts with intracranial stenting and superficial temporal-middle cerebral artery (STA-MCA) bypass failed to show benefit. Perhaps, better strategies are needed for selecting suitable patients. Acetazolamide-challenged single photon emission computed tomography (SPECT) can demonstrate reversed Robin Hood syndrome (RRHS) due to intracranial steal phenomenon and identify high-risk patients.Methods: We describe the clinical and SPECT findings of RRHS.Results: In our patient with severe and symptomatic severe stenosis of the right MCA, STA-MCA bypass resulted in complete resolution of RRHS.Conclusion: STA-MCA bypass surgery should be considered a possible option in patients with severe stenosis of intracranial internal carotid artery or MCA in carefully selected patients.

EEG Analysis and Spect Imaging in Alzheimer's Disease, Vascular Dementia and Mild Cognitive Impairment.

Alzheimer's disease (AD) and vascular dementia (VaD) represent a leading public-health problem given the rising age of the population. Early diagnosis of dementia, especially at the stage of mild cognitive impairment (MCI) has become an important goal of the modern patient work-up. Brain perfusion single-photon emission computed tomography (SPECT) has become a mainstay of diagnostic algorithms in patients with dementia showing specific patterns of hypoperfusion in temporal and parietal lobes. Clinical electroencephalography (EEG) is a relatively simple and inexpensive diagnostic tool showing potential in assessing cortical thinning and lower perfusion in temporoparoetal regions. Our study was a cross sectional and included retrospective analysis of the group of patients diagnosed with AD, VaD and MCI. The study group consisted of 50 patients - 29 females and 21 males. All patients underwent EEG and SPECT analysis as part of regular work-up. Patients with AD exhibit EEG changes mostly in the form of theta waves, focal abnormalities and spike-and-wave complexes in frontotemporal regions with the reduction in the amplitude of alpha waves. SPECT in most patients exhibited hypoperfusion in temporoparietal regions with occasional unilateral abnormalities in frontotemporal region. EEG changes in patients with VaD are predominantly in the form of theta waves while SPECT findings show mostly "patchy" abnormalities. EEG readings are normal or exhibit minimal changes in the group of patients with MCI, while SPECT imaging exhibits mostly normal CBF. EEG and SPECT are diagnostic methods which show specific changes, especially in AD. EEG can be used to monitor the therapeutic effect and progression of AD as well as the possible transition from MCI to early stage AD. SPECT on the other hand, being a more expensive and less available method, can be utilized as an add-on method to increase the specificity and sensitivity of the diagnostic algorithm.

Clinical Characteristics and Neuroimaging Findings in Internal Jugular Venous Outflow Disturbance.

Recently, internal jugular vein stenosis (IJVS) is gaining increasing attention from clinical researchers due to a series of confounding symptoms that impair the quality of life in affected individuals but cannot be explained by other well-established causes. In this study, we aimed to elucidate the clinical features, neuroimaging characteristics and pathogenesis of IJVS, and explore their possible correlations, in attempt to provide useful clues for clinical diagnosis and treatment. Forty-three eligible patients with unilateral or bilateral IJVS confirmed by contrast-enhanced magnetic resonance venography of the brain and neck were enrolled in this study. Magnetic resonance imaging along with magnetic resonance angiography or computed tomography angiography was applied to identify the radiological pattern of parenchymal or arterial lesions. Cerebral perfusion and metabolism were evaluated by single-photon emission computed tomography (SPECT). Of the 43 patients (46.0 ± 16.0 years old; 30 female), 14 (32.6%) had bilateral and 29 had unilateral IJVS. The common clinical symptoms at admission were tinnitus (60.5%), tinnitus cerebri (67.6%), headache (48.8%), dizziness (32.6%), visual disorders (39.5%), hearing impairment (39.5%), neck discomfort (39.5%), sleep disturbance (60.5%), anxiety or depression (37.5%) and subjective memory decline (30.2%). The presence of bilateral demyelination changes with cloudy-like appearance in the periventricular area and/or centrum semiovale was found in 95.3% (41/43) patients. SPECT findings showed that 92.3% (24/26) patients displayed cerebral perfusion and metabolism mismatch, depicted by bilaterally and symmetrically reduced cerebral perfusion and increased cerebral glucose consumption. IJVS may contribute to alterations in cerebral blood flow and metabolism, as well as white matter lesion formation, all of which may account for its clinical manifestations.