Use Of Single-photon Emission Computed Tomography Research Articles

The Legacy of the TTASAAN Report - Premature Conclusions and Forgotten Promises About SPECT Neuroimaging: A Review of Policy and Practice Part II.

Brain perfusion single photon emission computed tomography (SPECT) scans were initially developed in 1970s. A key radiopharmaceutical, hexamethylpropyleneamine oxime (HMPAO), was not stabilized until 1993 and most early SPECT scans were performed on single-head gamma cameras. These early scans were of inferior quality. In 1996, the Therapeutics and Technology Assessment Subcommittee of the American Academy of Neurology (TTASAAN) issued a report regarding the use of SPECT in the evaluation of neurological disorders. This two-part series explores the policies and procedures related to perfusion SPECT functional neuroimaging. In Part I, the comparison between the quality of the SPECT scans and the depth of the data for key neurological and psychiatric indications at the time of the TTASAAN report vs. the intervening 25 years were presented. In Part II, the technical aspects of perfusion SPECT neuroimaging and image processing will be explored. The role of color scales will be reviewed and the process of interpreting a SPECT scan will be presented. Interpretation of a functional brain scans requires not only anatomical knowledge, but also technical understanding on correctly performing a scan, regardless of the scanning modality. Awareness of technical limitations allows the clinician to properly interpret a functional brain scan. With this foundation, four scenarios in which perfusion SPECT neuroimaging, together with other imaging modalities and testing, lead to a narrowing of the differential diagnoses and better treatment. Lastly, recommendations for the revision of current policies and practices are made.

The Legacy of the TTASAAN Report-Premature Conclusions and Forgotten Promises: A Review of Policy and Practice Part I.

Brain perfusion single photon emission computed tomography (SPECT) scans were initially developed in 1970's. A key radiopharmaceutical, hexamethylpropyleneamine oxime (HMPAO), was originally approved in 1988, but was unstable. As a result, the quality of SPECT images varied greatly based on technique until 1993, when a method of stabilizing HMPAO was developed. In addition, most SPECT perfusion studies pre-1996 were performed on single-head gamma cameras. In 1996, the Therapeutics and Technology Assessment Subcommittee of the American Academy of Neurology (TTASAAN) issued a report regarding the use of SPECT in the evaluation of neurological disorders. Although the TTASAAN report was published in January 1996, it was approved for publication in October 1994. Consequently, the reported brain SPECT studies relied upon to derive the conclusions of the TTASAAN report largely pre-date the introduction of stabilized HMPAO. While only 12% of the studies on traumatic brain injury (TBI) in the TTASAAN report utilized stable tracers and multi-head cameras, 69 subsequent studies with more than 23,000 subjects describe the utility of perfusion SPECT scans in the evaluation of TBI. Similarly, dementia SPECT imaging has improved. Modern SPECT utilizing multi-headed gamma cameras and quantitative analysis has a sensitivity of 86% and a specificity of 89% for the diagnosis of mild to moderate Alzheimer's disease—comparable to fluorodeoxyglucose positron emission tomography. Advances also have occurred in seizure neuroimaging. Lastly, developments in SPECT imaging of neurotoxicity and neuropsychiatric disorders have been striking. At the 25-year anniversary of the publication of the TTASAAN report, it is time to re-examine the utility of perfusion SPECT brain imaging. Herein, we review studies cited by the TTASAAN report vs. current brain SPECT imaging research literature for the major indications addressed in the report, as well as for emerging indications. In Part II, we elaborate technical aspects of SPECT neuroimaging and discuss scan interpretation for the clinician.

Clinical Utility of SPECT in the Heart Transplant Population: Analysis From a Single Large-volume Center.

Survival after heart transplant has greatly improved, with median survival now over 12 years. Cardiac allograft vasculopathy (CAV) has become a major source of long-term morbidity and mortality. Single-photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) is used for CAV surveillance, but there is limited data on its prognostic utility. We retrospectively identified patients undergoing SPECT MPI for CAV surveillance at a single, large-volume center. Images were assessed with semiquantitative visual scoring (summed stress score [SSS] and summed rest score) and quantitatively with total perfusion defect (TPD). We studied 503 patients (mean age 62.5, 69.3% male) at a median of 9.0 years post-transplant. During mean follow-up of 5.1 ± 2.5 years, 114 (22.6%) patients died. The diagnostic accuracy for significant CAV (ISHLT grade 2 or 3) was highest for SSS with an area under the curve of 0.650 and stress TPD (area under the curve, 0.648), with no significant difference between SSS and stress TPD (P = 0.061). Stress TPD (adjusted hazard ratio, 1.07; P = 0.018) was independently associated with all-cause mortality, while SSS was not (P = 0.064). The prognostic accuracy of quantitative assessment of perfusion tended to be higher compared with semiquantitative assessment, with the highest accuracy for stress TPD (area under the receiver operating curve 0.584). While SPECT MPI identified a cohort of higher risk patients, with quantitative analysis of perfusion demonstrating higher prognostic accuracy. However, the overall prognostic accuracy was modest and alternative noninvasive modalities may be more suitable for CAV surveillance.

A New Way Forward: How Brain SPECT Imaging Can Improve Outcomes and Transform Mental Health Care Into Brain Health Care.

In the past three decades, brain single-photon-emission-computed-tomography (SPECT) imaging has garnered a significant, evidence-based foundation for a wide array of indications relevant to the field of clinical psychiatry, including dementia, traumatic brain injuries, seizures, cerebrovascular disease, complex neuropsychiatric presentations, and treatment-resistant disorders. In clinical psychiatric practice, however, SPECT remains underutilized. Only a small percentage of psychiatric clinicians use brain imaging technology. In this article, the authors provide a rationale for shifting the paradigm to one that includes broader use of SPECT in the clinical psychiatric setting, primarily for patients with complex conditions. This paper will outline seven specific clinical applications. Adding neuroimaging tools like SPECT to day-to-day clinical practice can help move psychiatry forward by transforming mental health care, which can be stigmatizing and often shunned by the general public, to brain health care, which the authors argue will be more likely to be embraced by a larger group of people in need.

Single‐photon emission computed tomography of the pelvis and lumbar spine contributes to the diagnosis of injury in two horses

SummaryLameness originating from injury to the pelvis and lumbar spine remains a diagnostic challenge for equine veterinarians. Nuclear scintigraphy is frequently used to aid in the localisation of injuries to this region; however, the lack of image contrast due to anatomical superimposition in the pelvis and lumbar spine complicates image interpretation. To the authors’ knowledge, the use of single‐photon emission computed tomography (SPECT) has not been previously reported in the horse. This article describes the clinical use of SPECT in the horse to aid the diagnosis of injury to the region of the sacroiliac joint and lumbar vertebrae which was not identified on planar imaging.

The Use of Single-Photon-Emission Computed Tomography (SPECT) for the Evaluation of Painful Ankle Arthroplasties

Category:Ankle; Ankle ArthritisIntroduction/Purpose:The evaluation of the painful ankle arthroplasty remains challenging. Clinical and radiographic examination are the mainstay of surveillance. The use of CT is also widespread. In our series using CT we were however unable to reliably differentiate between prosthetic and other causes of pain. We do not therefore recommend the use of CT in evaluating this patient group. Since 2017 we have evaluated all cases of painful ankle replacement with single-photon-emission computed tomography (SPECT). The aim of this study was to review the use of SPECT in our patient cohort.Methods:A retrospective analysis of all ankle arthroplasties evaluated by SPECT was performed. Case notes, plain radiographic imaging and SPECT imaging were reviewed and tabulated for analysis.Results:29 painful ankle arthroplasties were identified and included in this study. Implants included 14 BOX, 11 Mobility, 3 Salto xt and 1 Zenith. The mean time from index surgery was 5 years (1 -11 years). Plain radiographs demonstrated no obvious abnormality in 18 out of 29 patients. Of these SPECT demonstrated abnormal periprosthetic uptake suggestive of loosening in 12 out of 18, in the remaining 6 no loosening / ankle pathology was identified. Of these 6 patients SPECT identified an area of extra- articular high uptake suggestive of a pain source in 3 cases (1 talonavicular joint, 1 subtalar joint and 1 syndesmosis). In the 11 patients with a demonstrable abnormality suggestive of loosening on plain imaging, SPECT confirmed the diagnosis in all 11 cases.Conclusion:SPECT is a useful tool in the evaluation of the painful ankle arthroplasty. SPECT provided confirmatory information where plain radiographs were positive but also helped elucidate potential causes of pain where plain radiographs were negative. We would no longer recommend the routine use of CT but rather would recommend the use of SPECT in the evaluation of all painful ankle arthroplasties.

264. Assessment of impact of single photon emission computed tomography (SPECT) on management of degenerative cervical and lumbar disease: a multi-institution survey of spine surgeons

BACKGROUND CONTEXT Use of SPECT for evaluation of the spine has been postulated to provide diagnostic information through localization of metabolic bone activity leading to clinically relevant pain and dysfunction. No study has prospectively assessed the impact of SPECT on clinical decision making in degenerative spinal disease. PURPOSE To evaluate whether the addition of SPECT in the multi-level degenerative spine results in changes to management plans compared to standard imaging in a multi-institutional survey of spine surgeons. STUDY DESIGN/SETTING Surgeon survey. PATIENT SAMPLE Twenty-seven spine surgeons participated in an online survey of 10 patient cases. OUTCOME MEASURES Change in treatment decision and invasiveness. METHODS Ten cases of degenerative spinal disease (7 lumbar and 3 cervical) were presented online with vignettes and relevant imaging. Surgeons selected a treatment category for each patient (pain management procedure (PM), surgery (S), or nonoperative (NO)). Based on answer choice they then selected a specific treatment plan (NO v PM v S), with surgical options ranging from least to most invasive. Cases were then reordered and presented with SPECT included. Percentage of treatment changes across cases was calculated. Management changes by surgeons were analyzed across decision categories: NO to S, NO to PM, PM to NO, PM to S, S to NO, and S to PM. RESULTS Twenty-seven spine surgeons completed both surveys totaling 540 responses. Respondents self-classified their practices as academic, private, or mixed (33.3% each). A total of 60.7% of surgeons stated they do not regularly use SPECT and of those 41.2% stated the primary reason was that they were unaware of its diagnostic utility in spine. Management decisions were changed 48% of the time with addition of SPECT to the work up with changes in overall treatment category 34% of the time. The number of treatment changes across decision categories was significant (p CONCLUSIONS In evaluating patients with degenerative spinal disease, the use of SPECT may provide valuable additional information to guide decision making. In this survey the addition of SPECT resulted in surgeons changing their treatment to a less invasive intervention 42% of the time. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

Utility of single-photon emission computed tomography (SPECT) in presurgical evaluation of children: A single-center experience

ObjectiveSingle-photon emission computed tomography (SPECT) is an ancillary noninvasive test commonly used to identify the epileptogenic zone. However, its proper utilization may be limited depending on the resources available at each center. This study aimed to investigate the utility of SPECT in presurgical evaluation of children at our center. MethodsThis was an observational retrospective study in 150 children who were admitted to the Epilepsy Monitoring Unit for presurgical evaluation between 2012 and 2019. The utility of interictal and ictal SPECT in different clinical cohorts was analyzed. ResultsOnly interictal SPECT was performed on 87 patients (58 %), while ictal SPECT was performed on 62 (41.3 %), and interictal SPECT alone was considered of low diagnostic value. Ictal SPECT was unremarkable in 27 of 62 patients and abnormal in 35. Ictal SPECT was localized to the temporal lobe in 62.8 % and to the extratemporal lobe in 25.7 % of the patients and lateralized to one hemisphere in 11.4 % of the patients. In the abnormal SPECT group, ictal SPECT was considered unnecessary in 7/35 (20 %) patients with a single lesion and 3/35 (8.5 %) patients with a hemispheric lesion. In the remaining 25 patients, surgery was recommended more frequently than invasive EEG monitoring (IEM) for diffuse lesion cases (P = 0.03), while IEM was recommended more frequently than surgery for MRI-negative cases (P = 0.03), and in this group none of the MRI-negative patients underwent surgery. In our entire cohort, epilepsy surgery was performed on 24.4 % of the patients, 64 % with a single lesion, 7.6 % with a hemispheric lesion, 25.6 % with a diffuse lesion, and only one MRI-negative patient (2.5 %). Surgery was performed in 48.7 % of single lesion cases and 20.5 % of diffuse lesion cases with either unremarkable or no ictal SPECT. Engel class I outcome was achieved in 62 % and class II outcome in 33 % of the patients. In the single lesion etiology, 72 % (18/25) patients achieved excellent outcome and within this group, 22 % (4/18) patients had a positive ictal SPECT whereas 78 % (14/18) patients either did not get an ictal SPECT or it was unremarkable. SignificanceBased on our findings, we suggest carefully selecting patients for SPECT imaging to improve its utility and prevent overutilization and potential harm to children.

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.

Quantitative SPECT: a survey of current practice in the UK Nuclear Medicine Community.

Nuclear Medicine is a quantitative imaging modality. However, until recently, quantitative single photon emission computed tomography (SPECT) has been limited to ratios or comparisons to databases, or indeed volume measurements, and therefore has not truly quantified uptake in areas of interest. Following the growth of dosimetry associated with nuclear medicine therapies, tools to perform quantitative SPECT in terms of kBq/cc or standardised uptake value (SUV) have become more readily available, although its use does not appear to be widespread. The aim of this study was to get a snapshot of quantitative SPECT use, and to determine where the future of this technology may lie. The data for this survey were collected through a web-based form made available at a national quantitative SPECT meeting, and later distributed to the UK nuclear medicine community. A series of questions looking at current practice, technique and future thoughts were presented to respondents in the form of multiple-choice questions where single and multiple selections could be made. The responses showed significant use of quantitative SPECT for established techniques, in alignment with the prevalence of the relevant imaging studies. There was a significant minority of respondents performing kBq/cc and SUV SPECT, and SPECT for radionuclide therapy dosimetry. Technique for quantitative SPECT varied significantly typically but nevertheless the predicted future for quantitative SPECT was positive: particularly for kBq/cc and SUV SPECT. Impediments to the success of the technology were mostly around software availability and uncertainties around usefulness. The results of this survey suggest that the future of truly quantitative SPECT looks promising.

Wartość prognostyczna scyntygrafii perfuzyjnej mięśnia sercowego metodą SPECT z użyciem 99mTc-MIBI w grupie pacjentów po przebytym w przeszłości zawale serca

Introduction. Data describing prognostic utility of SPECT (single-photon emission computed tomography) among patients with history of myocardial infarction (MI) is scarce. We aimed to compare prognostic value of SPECT scans in patients with vs. without history of myocardial infarction (MI) prior to perfusion imaging. Material and methods. 151 consecutive patients with history of myocardial infarction, who underwent exercise 99mTc-MIBI SPECT examination were enrolled in the study (group 1). Next, based on clinical and demographic baseline characteristics, SPECT result and duration of follow-up period, a matching control subgroup (group 2) of 151 patients without history of MI was formed. During a mean follow-up of 60 ± 15 months in group 1 and a mean follow-up of 60 ± 13.5 months in group 2, we analyzed prevalence of cardiovascular events rates (cardiac deaths, myocardial infarctions and cardiac revascularizations). Results. We observed the following rates of cardiac deaths, myocardial infarctions and cardiac revascularizations: 4%, 15% and 26%, respectively in group 1 and 1%, 13% and 17%, respectively in group 2. In patients without history of MI (group 2) presence of mixed perfusion defects on SPECT was associated with significantly higher rate of myocardial infarctions (p = 0.05), hospitalizatons (p = 0.0001) and revascularizations (p = 0.0002). Fixed perfusion defects were associated with significantly higher occurrence of deaths (p = 0.012) and hospitalizations (p = 0.02), but not myocardial infarctions (p = 0.52) or cardiac revascularizations (p = 0.10). In contrast, among patients with history of MI (group 1) there was no statistically significant relationship between any type of perfusion defects and cardiovascular events. Conclusions. Long term follow-up demonstrates that prognostic value of 99mTc-MIBI SPECT is different in patients with and without history of MI.

Combining SPECT and Quantitative EEG Analysis for the Automated Differential Diagnosis of Disorders with Amnestic Symptoms.

Single photon emission computed tomography (SPECT) and Electroencephalography (EEG) have become established tools in routine diagnostics of dementia. We aimed to increase the diagnostic power by combining quantitative markers from SPECT and EEG for differential diagnosis of disorders with amnestic symptoms. We hypothesize that the combination of SPECT with measures of interaction (connectivity) in the EEG yields higher diagnostic accuracy than the single modalities. We examined 39 patients with Alzheimer's dementia (AD), 69 patients with depressive cognitive impairment (DCI), 71 patients with amnestic mild cognitive impairment (aMCI), and 41 patients with amnestic subjective cognitive complaints (aSCC). We calculated 14 measures of interaction from a standard clinical EEG-recording and derived graph-theoretic network measures. From regional brain perfusion measured by 99mTc-hexamethyl-propylene-aminoxime (HMPAO)-SPECT in 46 regions, we calculated relative cerebral perfusion in these patients. Patient groups were classified pairwise with a linear support vector machine. Classification was conducted separately for each biomarker, and then again for each EEG- biomarker combined with SPECT. Combination of SPECT with EEG-biomarkers outperformed single use of SPECT or EEG when classifying aSCC vs. AD (90%), aMCI vs. AD (70%), and AD vs. DCI (100%), while a selection of EEG measures performed best when classifying aSCC vs. aMCI (82%) and aMCI vs. DCI (90%). Only the contrast between aSCC and DCI did not result in above-chance classification accuracy (60%). In general, accuracies were higher when measures of interaction (i.e., connectivity measures) were applied directly than when graph-theoretical measures were derived. We suggest that quantitative analysis of EEG and machine-learning techniques can support differentiating AD, aMCI, aSCC, and DCC, especially when being combined with imaging methods such as SPECT. Quantitative analysis of EEG connectivity could become an integral part for early differential diagnosis of cognitive impairment.

Perfusion SPECT in the differential diagnosis of dementia

Dementia is a syndrome–usually of a chronic or progressive nature–in which there is deterioration in cognitive function beyond what might be expected from normal ageing (WHO). As the world population ages, the number of people afflicted with dementing illnesses will increase. This neurodegenerative disease is one of the major causes of disability and dependency among older people worldwide. Brain single-photon emission computed tomography (SPECT) allows the study of regional cerebral blood flow, providing functional information. Each of the different types of dementia has a distinct blood flow pattern that is revealed with SPECT imaging and which can be used for differential diagnoses. This imaging technique can also be used to differentiate dementia from pseudodementia. The use of SPECT has been recommended in various guidelines to help in differential diagnosis of dementia. The National Institute for Health and Clinical Excellence in the UK recommend the use of SPECT or positron emission tomography (PET) to help differentiate Alzheimer's disease (AD) from frontotemporal dementia and vascular dementia when there is diagnostic doubt (NICE, 2006). The European Federation of the Neurological Societies guidelines for diagnosis also supports the use of FDG-PET (18F fluorodeoxyglucose positron emission tomography) or perfusion SPECT when clarifying a diagnosis of AD. This review describes the utility of perfusion SPECT in differential diagnosis of neurodegenerative dementias.Disclosure of interestThe authors have not supplied their declaration of competing interest.

Evidence on Use of Neuroimaging for Surgical Treatment of Temporal Lobe Epilepsy: A Systematic Review.

Surgery is an effective treatment for drug-resistant focal epilepsy. Neuroimaging studies are considered essential in the diagnostic evaluation of individuals with medically refractory focal seizures being considered for surgical treatment. To review the evidence for the use of neuroimaging studies in the selection of patients with drug-resistant temporal lobe epilepsy for focal cortical resection and discuss the prognostic importance of selected techniques. Randomized clinical trials, meta-analyses, and clinical retrospective case studies (≥20 patients with ≥1 year of follow-up) were identified using Medical Subject Headings and indexed text terms in EMBASE (1988-November 29, 2014); MEDLINE (1946-December 2, 2014), Cochrane Central Register of Controlled Trials (1991-October 31, 2014), and Cochrane Database of Systematic Reviews (2005-October 31, 2014). Twenty-seven articles describing 3163 patients were included. Neuroimaging techniques analyzed included magnetic resonance imaging (MRI), positron emission tomography (PET), and single-photon emission computed tomography (SPECT). Subpopulations and prognostic factors were identified. Of the 27 studies evaluated (3163 patients), 7 showed the outcome was more favorable in patients with MRI-identified hippocampal atrophy indicating mesial temporal sclerosis. Five additional studies indicated that the outcome was less favorable in patients with unremarkable MRI studies. There are conflicting findings regarding the prognostic importance of PET-identified focal hypometabolism; however, 2 investigations indicated that the presence of a PET imaging study demonstrating abnormalities in individuals with unremarkable MRI results showed an operative outcome similar to that in patients with mesial temporal sclerosis. The studies assessing SPECT use in temporal lobe epilepsy did not reveal a correlation with outcome. There is strong evidence that preoperative MRI-identified hippocampal atrophy consistent with mesial temporal sclerosis concordant with the seizure origin in the temporal lobe is a significant factor associated with a favorable outcome. PET studies may be valuable in individuals with unremarkable MRI findings. The current evidence does not support the prognostic importance of SPECT in patients undergoing temporal lobe surgery.

Old wine in new bottles: Validating the clinical utility of SPECT in predicting cognitive performance in mild traumatic brain injury

The neural underpinnings of cognitive dysfunction in mild traumatic brain injury (TBI) are not fully understood. Consequently, patient prognosis using existing clinical imaging is somewhat imprecise. Single photon emission computed tomography (SPECT) is a frequently employed investigation in this population, notwithstanding uncertainty over the clinical utility of the data obtained. In this study, subjects with mild TBI underwent 99mTc-ECD SPECT scanning, and were administered a brief battery of cognitive tests and self-report symptom scales of concussion and emotional distress. Testing took place 2 weeks (n=84) and 1 year (n=49) post-injury. Multivariate analysis (i.e., partial least squares analysis) revealed that frontal perfusion in right superior frontal and middle frontal gyri predicted poorer performance on the Stroop test, an index of executive function, both at initial and follow-up testing. Conversely, SPECT scans categorized as normal or abnormal by radiologists did not differentiate cognitively impaired from intact subjects. These results demonstrate the clinical utility of SPECT in mild TBI, but only when data are subjected to blood flow quantification analysis.

SPECT Nuclear Imaging: Improved Diagnostic Tool in Infants With Biliary Atresia

Introduction: Biliary atresia is an idiopathic disorder characterized by progressive obliteration of the biliary system in infancy and is the most common indication for liver transplant in children. Conventional nuclear hepatobiliary scanning (CN) is used in the evaluation of infants with neonatal cholestasis to identify biliary atresia and to proceed with more invasive diagnostic testing. Three-dimensional singlephoton emission computed tomography (SPECT) nuclear scan removes out of plane information using a gamma camera that rotates around the patient and may increase diagnostic accuracy when augmented to CN imaging. Limited data is known pertaining to the utility of SPECT as a single diagnostic modality in neonatal cholestasis. The study objective was to compare SPECT with CN imaging in the investigative work-up of infants with neonatal cholestasis to identify biliary atresia. Methods: Infants with unexplained neonatal cholestasis were included. All were pretreated with phenobarbital for 5 days prior to nuclear hepatobiliary imaging technique. Clinical and biochemical parameters analyzed were: age at time of scan, gender, anthropometric data, standard liver function tests, coagulation tests, nuclear medicine scan modality and study time. Nuclear imaging techniques were compared. A Student t test was used to compare groups. Results: The study group consisted of 17 patients (9 females). Demographic, clinical and biochemical parameters including weight, age, AST, ALT, GGT, total bilirubin, direct bilirubin and prothrombin time were statistically similar between the CN and SPECT groups. All patients underwent CN; 8 had both CN and SPECT performed (Table 1). Biliary atresia was diagnosed in 10 patients; idiopathic neonatal cholestasis in 4 patients; Alagille syndrome in 1 patient; delta-F508 cystic fibrosis in 1 patient; and TPN cholestasis in 1 patient.Table 1: Study ResultsConclusion: Three-dimensional SPECT nuclear hepatobiliary imaging demonstrates significantly reduced study time and exhibits comparable diagnostic accuracy as conventional nuclear hepatobiliary imaging in the work-up of cholestatic infants with suspected biliary atresia. These results suggest that SPECT may be used alone in identifying infants with biliary atresia with significant reduction in study time. Further studies are warranted to confirm these findings.

Incremental prognostic value of sequential imaging of single-photon emission computed tomography and coronary computed tomography angiography in patients with suspected coronary artery disease

This study was conducted to investigate the incremental prognostic value of sequential use of single-photon emission computed tomography (SPECT) and coronary computed tomography angiography (CCTA) in patients with suspected coronary artery disease (CAD). A total of 1295 patients with suspected CAD who underwent both CCTA and SPECT within 90 days was retrospectively reviewed in three cardiac centres. Cardiovascular events including cardiac death, non-fatal myocardial infarction, unstable angina, and late (> 90 days of imaging tests) revascularization were assessed. During the mean follow-up period of 795 ± 566 days (median, 735 days), there were 109 events (8.4%). Perfusion defect on SPECT and significant stenosis (≥ 50%) on CCTA were independent predictors for events. Sequential use of both imaging tests significantly improved prediction of the cardiovascular events. The incremental prognostic value of SPECT was significant in patients with stenosis of <90% but not in patients with stenosis of ≥ 90% on CCTA. Similarly, the incremental prognostic value of CCTA was significant in patients with the summed stress score (SSS) <4 but not in patients with SSS ≥ 4 on SPECT. Sequential use of SPECT and CCTA showed an incremental prognostic value in patients with suspected CAD. However, additional benefits were not significant when CCTA revealed stenosis of ≥ 90% or SPECT revealed SSS ≥ 4. These results suggest an effective risk stratification strategy for sequential use of SPECT and CCTA, and maximizing the benefits in these patients.

Skeletal muscle satellite cell migration to injured tissue measured with111In-oxine and high-resolution SPECT imaging

The delivery of adult skeletal muscle stem cells, called satellite cells, to several injured muscles via the circulation would be useful, however, an improved understanding of cell fate and biodistribution following their delivery is important for this goal to be achieved. The objective of this study was to evaluate the ability of systemically delivered satellite cells to home to injured skeletal muscle using single-photon emission computed tomography (SPECT) imaging of (111)In-labeled satellite cells. Satellite cells labeled with (111)In-oxine and green fluorescent protein (GFP) were injected intravenously after bupivicaine-induced injury to the tibialis anterior muscle. Animals were imaged with a high-resolution SPECT system called FastSPECT II for up to 7 days after transplantation. In vivo FastSPECT II imaging demonstrated a three to five-fold greater number of transplanted satellite cells in bupivicaine-injured muscle as compared to un-injured muscle after transplantation; a finding that was verified through autoradiograph analysis and quantification of GFP expression. Satellite cells also accumulated in other organs including the lung, liver, and spleen, as determined by biodistribution measurements. These data support the ability of satellite cells to home to injured muscle and support the use of SPECT and autoradiograph imaging techniques to track systemically transplanted (111)In labeled satellite cells in vivo, and suggest their homing may be improved by reducing their entrapment in filter organs.

Systematic review of the diagnostic utility of SPECT imaging in dementia

Single-photon emission-computed tomography (SPECT) may potentially contribute to the diagnostic work up of patients with neurodegenerative dementia. This systematic review aims to establish the diagnostic utility of 99mTc-hexamethylpropyleneamine (99mTc-HMPAO) and 99mTc-ethylcysteine dimer SPECT in distinguishing between Alzheimer's disease (AD) and frontotemporal dementia (FTD), AD and vascular dementia (VD), AD and dementia with Lewy bodies (DLB), and AD and normal controls (NC). We searched MEDLINE and Embase databases via OVID for articles from January 1985 to May 2012 and identified additional studies from reviews and references. Of 755 studies, 49 studies met the inclusion and exclusion criteria for this systematic review; AD versus FTD (n=13), AD versus VD (n=18), AD versus DLB (n=5), and AD versus NC (n=18). We compiled relevant data and graded the studies with an internal and external validity criteria checklist. We pooled the studies with a clinical diagnosis and those using 99mTc-HMPAO SPECT in a meta-analysis, calculating the pooled weighted sensitivity, specificity, likelihood ratios, and diagnostic odds ratios using DerSimonian-Laird random-effects model. The pooled weighted sensitivity and specificity of 99mTc-HMPAO-SPECT in distinguishing clinically diagnosed AD from FTD are 79.7 and 79.9%, respectively, AD from VD are 74.5 and 72.4%, AD from DLB are 70.2 and 76.2%, and AD from NC are 76.1 and 85.4%. SPECT does have diagnostic value, particularly in differentiating Alzheimer's disease from frontotemporal dementia and normal controls; however, it should not be used in isolation, rather as an adjunct, and interpreted in the context of clinical information and paraclinical test results.

Long-term follow-up study of gastroduodenal lesions after radioembolization of hepatic tumors

To evaluate the long-term natural history of the gastroduodenal lesions secondary to extrahepatic embolization with Ytrium 90 (⁹⁰Y) spheres. From September 2003 to January 2012, 379 procedures of liver radioembolization (RE) using resin microspheres loaded with ⁹⁰Y were performed in our center. We have retrospectively compiled the data from 379 RE procedures performed in our center. We report a comprehensive clinical, analytical, endoscopic and histologic long-term follow-up of a series of patients who developed gastroduodenal lesions after the treatment. Six patients (1.5%) developed gastrointestinal symptoms and had gastrointestinal lesions as shown by upper endoscopy in the next 12 wk after RE. The mean time between RE and the appearance of symptoms was 5 wk. Only one patient required endoscopic and surgical treatment. The incidence of gastrointestinal ulcerations was 3.75% (3/80) when only planar images were used for the pre-treatment evaluation. It was reduced to 1% (3/299) when single-photon emission computed tomography (SPECT) images were also performed. The symptoms that lasted for a longer time were nausea and vomiting, until 25 mo after the treatment. All patients were free from severe symptoms at the end of follow-up. The routine use of SPECT has decreased the incidence of gastrointestinal lesions due to unintended deployment of ⁹⁰Y particles.