Comparison of cardio-focal and chest reconstruction of technetium-99m pyrophosphate scintigraphy for diagnosis of transthyretin cardiac amyloidosis: a quality assurance study.

BACKGROUND: SPECT improves diagnostic specificity of Technetium-99m pyrophosphate (PYP) scintigraphy. Diagnostic performance of PYP data, reconstructed as either chest or cardio-focal SPECT is not known. METHODS: In this quality assurance study, blinded evaluation of PYP SPECT/CT data from 102 Caucasian patients (mean age 76 ± 11 years, 67% men) was performed by two readers. Reader 1 reviewed planar and PYP chest SPECT, while reader 2 reviewed planar and cardio-focal PYP SPECT. Demographic, clinical, and other testing data were obtained from the electronic medical records. RESULTS: A total of 41 patients (40%) were considered positive based on myocardial uptake on chest PYP SPECT. Of these, 98% of the patients had a Perugini score ≥ 2 on planar imaging. There was good agreement between the two readers for visual score ≥ 2 (k = .88, P < .001) and excellent agreement for myocardial uptake on tomographic imaging (98%, P < .001). Only one study was categorized as false negative by cardio-focal SPECT reconstruction. Non-diffuse myocardial uptake was identified in 22% of those with a positive PYP SPECT. CONCLUSION: When read by experienced readers, chest and cardio-focal reconstruction of PYP SPECT have comparable diagnostic performance. A substantial proportion of patients with a positive PYP SPECT have a non-diffuse distribution of PYP. Given the possibility of misclassification of non-diffuse myocardial uptake on cardio-focal reconstruction alone, chest reconstruction of PYP scintigraphy should be strongly considered.

Very high coronary artery calcium score with normal myocardial perfusion SPECT imaging is associated with a moderate incidence of severe coronary artery disease.

PURPOSE: Myocardial perfusion imaging (MPI) has limitations in the presence of balanced multivessel disease (MVD) and left main (LM) coronary artery disease, occasionally resulting in false-normal results despite the high cardiovascular risk associated with this condition. The purpose of this study was to assess the incidence of severe coronary artery disease (CAD) in the presence of a very high Agatston coronary artery calcium (CAC) score (>1,000) in stable symptomatic patients without known CAD but with normal MPI results. METHODS: A total of 2,659 prospectively acquired consecutive patients were referred for MPI and evaluation of CAC score by CT. Of this patient population, 8 % (222/2,659) had ischemia without myocardial infarction (MI) on MPIand 11 % (298/2,659) had abnormal MPI (MI and/or ischemia). On presentation 1 % of the patients (26/2,659) were symptomatic, had a CAC score >1,000 and normal MPI results. The definition of normal MPI was strict and included a normal hemodynamic response without ischemic ECG changes and normal imaging, particularly absence of transient ischemic dilation. All of these 26 patients with a CAC score >1,000 and normal MPI findings underwent cardiac catheterization. RESULTS: Of these 26 patients, 58 % (15/26) had severe disease (≥70 % stenosis) leading to revascularization. Of this group, 47 % (7/15) underwent percutaneous intervention, and 53 % (8/15) underwent coronary artery bypass grafting. All of these 15 patients had either MVD (14/15) or LM coronary artery disease (1/15), and represented 0.6 % (15/2,659) of all referred patients (95 % CI 0.3 - 0.9 %). The majority, 90 % (8/9), had severe CAD with typical chest pain. CONCLUSION: A very high CAC score (>1,000) with normal MPI in a small subset of symptomatically stable patients was associated with a moderate incidence of severe CAD (95 % CI 37 - 77 %). Larger studies and/or a meta-analysis of small studies are needed to more precisely estimate the incidence of CAD in this population. This study also supports the concept that a normal MPI result in patients with severe CAD may be due to balanced MVD.

One-year outcome of the sevoflurane in acute myocardial infarction randomized trial.

BACKGROUND: Sevoflurane is an inhalation anesthetic that has cardioprotective effects. There is limited information regarding its use outside of the operating room and its potential protective effect for patients presenting with myocardial infarction. METHODS: In the Sevoflurane In Acute Myocardial Infarction trial, patients with a first acute ST-elevation myocardial infarction (STEMI) who were treated by primary percutaneous coronary intervention were randomized to inhalation of sevoflurane or oxygen (control). From the time of the patient's arrival for cardiac catheterization, the anesthesia team administered sevoflurane or oxygen for 30 min using a tight-fitting mask. In this substudy, we report the one-year outcomes. Patients were followed clinically for one year; they underwent a thallium cardiac viability study at six months and an echocardiogram at one year. RESULTS: Forty-six patients completed follow-up. One patient in the sevoflurane group died. The mean [standard deviation (SD)] ejection fraction by single-photon emission computed tomography at six months was 51.7 (7.7)% in the sevoflurane group and 51 (9.1)% in the control group (mean difference, 0.7%; 95% confidence interval [CI], -5.9 to 7.3; P = 0.831). The median [interquartile range] amount of scarring at six months was 0% [0 - 8] in the sevoflurane group and 2.5% [0 - 7.1] in control group (mean difference, -0.1%; 95% CI, -4.6 to 4.4; P = 0.700). The mean (SD) percentage of hibernating myocardium was similar in both groups 0% [0, 5] (mean difference, -1.3%; 95% CI, -3.4 to 0.9; P = 0.259). The mean (SD) ejection fraction at one year increased compared with baseline by 8.0 (9.1)% (P < 0.001). CONCLUSIONS: In this study, we did not find an effect of sevoflurane on left ventricular function or myocardial injury at one year post STEMI. This trial was registered at www.clinicaltrials.gov ; identifier: NCT00971607.

Prognostic value of coronary computed tomography angiography compared to radionuclide myocardial perfusion imaging in patients With coronary stents.

Objectives: The aim of this study is to compare the prognostic value of coronary computed tomography angiography (CCTA) with single-photon emission computed tomography (SPECT) in predicting cardiovascular events in patients with stents. Design: Retrospective analysis. Setting: University Hospital, London, Ontario Canada. Participants: Between January 2007 and December 2018, 119 patients post-percutaneous coronary intervention (PCI) who were referred for hybrid imaging with CTA and 2-day rest/stress SPECT were enrolled. Primary and secondary outcome measures: Patients were followed for any major adverse cardiovascular event (MACE) including: All-cause mortality, Non-fatal myocardial infarction (MI), Unplanned revascularization, Cerebrovascular accident and hospitalization for arrhythmia or heart failure. We define hard cardiac events (HCE) as: cardiac death, non-fatal MI or unplanned revascularization. We used two cut-off values to define obstructive lesions with CCTA ≥50% and ≥70% in any coronary segment. SPECT scan defined as abnormal in the presence of >5% reversible myocardial perfusion defect. Results: During the follow-up period of 7.2 ± 3.4 years. 45/119 (37.8%) patients experienced 57 MACE: Ten deaths (2 cardiac deaths and 8 of non-cardiac deaths), 29 acute coronary syndrome including non-fatal MI (25 required revascularization), 7 hospitalizations for heart failure, 6 cerebrovascular accidents and 5 new atrial fibrillation. 31 HCEs were reported. Cox regression analysis showed that obstructive coronary stenosis (≥50% and ≥70%) and abnormal SPECT were associated of MACE (p = 0.037, 0.018 and 0.026), respectively. In contrast, HCEs were significantly associated with obstructive coronary stenosis of ≥50% and ≥70% with p = 0.004 and p = 0.007, respectively. In contrast, abnormal SPECT was a nonsignificant predictor of HCEs (p = 0.062). Conclusion: Obstructive coronary artery stenosis on CCTA can predict MACE and HCE. However, abnormal SPECT can only predict MACE but not HCE in patients post-PCI with a follow-up period of approximately 7 years.

Complementary role of computed tomography angiography with fixed perfusion defects on SPECT myocardial perfusion imaging.

PURPOSE: We present this case series exploring the complementary role of coronary computed tomography angiography (CCTA) to SPECT myocardial perfusion imaging (MPI) in the detection of myocardial necrosis. METHODS: A cardiac hybrid imaging database search identified 144 patients with a previous history of ST-segment elevation myocardial infarction treated with coronary revascularization. CCTA and MPI scans were evaluated to determine whether CCTA had an added value to MPI in detecting myocardial necrosis. RESULTS: Five patients with patent stents and/or bypass grafts and both fixed perfusion defects on MPI and sub-endocardial hypo-perfusion on CCTA were identified. The extent and location of the perfusion defects were closely correlated between the CCTA and SPECT MPI images. CONCLUSION: In this series, CCTA and SPECT MPI were found to play a complementary role in the assessment of fixed perfusion defect, with CCTA adding specificity to the diagnosis of myocardial necrosis.

Internal Jugular Vein and Cerebral Venous Sinus Infective Thrombophlebitis Detected With 99mTc-HMPAO White Blood Cell Scintigraphy.

ABSTRACT: A 35-year-old man with a history of renal transplant, congenital cystinosis, and diabetes was admitted to the hospital with fever, bilateral parotid gland swelling, and acute renal failure. He had 99mTc-HMPAO-WBC (99mTc-hexamethylpropyleneamineoxime white blood cell) imaging for the evaluation of possible parotitis. There was intense radiopharmaceutical uptake along the right internal jugular vein extending to the right sigmoid and transverse and superior sagittal sinuses, suggestive of infective thrombophlebitis or Lemierre syndrome. This study illustrates the value of 99mTc-HMPAO-WBC imaging as a tool for evaluating thrombophlebitis, particularly in patients with renal failure in whom contrast-enhanced CT may not be possible.

Coronary artery calcium progression after coronary artery bypass grafting surgery.

OBJECTIVES: Accelerated atherosclerosis is a well-established phenomenon after coronary artery bypass grafting surgery (CABG). In this study, we analysed coronary artery calcium (CCS) progression after CABG. METHODS: We retrospectively measured the CCS Agatston score (AS), volume score (VS) and mass score (MS) of 39 patients before and after CABG. The annualised CCS change and annualised CCS percent change of each coronary artery, coronary artery segments proximal and distal to anastomosis were analysed. RESULTS: Mean age at the time of the surgery was 59.8±8.5 years. Follow-up period between the first and second CT scans was 6.7±2.8 (range, 1.1-12.8) years. Annualised CCS percent change (AS, VS and MS) of the coronary segments proximal-to-anastomosis did not differ from that of the non-grafted coronary arteries as follow: segments proximal-to-anastomosis: median (Q1-Q3) 12.8 (5.0-37.4), 13.7 (6.1-41.1) and 14.9 (5.4-53.7), left main coronary artery 12.6 (7.4-43.8), 22.0 (8.1-44.4) and 18.2 (7.3-57.4), non-grafted left circumflex artery: 13.5 (4.4-38.1), 10.5 (2.9-45.2) and 11.5 (7.1-47.9) and non-grafted right coronary artery: 31.4 (14.4-74.5), 25.2 (16.7-62.0) and 31.3 (23.8-85.6), respectively. Likewise, annualised percent change (AS, VS and MS) was similar between the native coronary arteries. Multivariate regression analysis showed that diabetes mellitus was the only predictor of annualised percent progression of the total CCS of >15% (HR, 8.12; 95% CI, 1.05 to 26.6; p=0.04). CONCLUSION: The CCS post-CABG did not follow an accelerated progression process. Among coronary artery disease risk factors, diabetes mellitus is the only predictor of annualised CCS percent progression of >15% post-CABG.

Hiatal hernia after robotic-assisted coronary artery bypass graft surgery.

BACKGROUND: The aim of the present study is to determine the incidence/progression of hiatal hernia (HH) after robotic-assisted coronary artery bypass grafting (RA-CABG) surgery. METHODS: We reviewed the pre- and post-operative computed tomography (CT) of 491 patients who underwent RA-CABG between 2000 and 2017. Post-operative CT was acquired prospectively in a research protocol. CT was reviewed to assess the presence and the size of HH. RESULTS: We found 444/491 (90.4%) had pre-operative CT, while 201/491 (40.9%) had post-operative CT. In total, 155/491 (31.6%) had both pre- and long-term post-operative CT with a mean follow-up of 6.2 (±3.5) years. HH was more prevalent on post-operative CT, 64/155 (41.3%) compared to pre-operative CT, 44/155 (28.4%), P<0.0001. The diameter of pre-existing HH 2.8 (±1.8) cm was significantly greater after surgery 3.9 (±2.5) cm, P<0.0001. As well the volume of the pre-existing HH 5.8 (4.4-9.2) mL (quartile) was significantly greater after surgery 14.1 (7.2-64.9) mL, P<0.0001. 20/155 (12.9%) had a newly developed HH after RA-CABG. A binary multivariate regression including HH risk factors showed that male gender is a predictor of developing a HH after RA-CABG with Hazard Ratio of 3.038, confidence interval (1.10-8.43), P=0.033. CONCLUSIONS: RA-CABG is associated with an increased risk of developing HH and increases the size of pre-existing HH.

Using simultaneous PET/MRI to compare the accuracy of diagnosing frontotemporal dementia by arterial spin labelling MRI and FDG-PET.

PURPOSE: The clinical utility of FDG-PET in diagnosing frontotemporal dementia (FTD) has been well demonstrated over the past decades. On the contrary, the diagnostic value of arterial spin labelling (ASL) MRI - a relatively new technique - in clinical diagnosis of FTD has yet to be confirmed. Using simultaneous PET/MRI, we evaluated the diagnostic performance of ASL in identifying pathological abnormalities in FTD (FTD) to determine whether ASL can provide similar diagnostic value as FDG-PET. METHODS: ASL and FDG-PET images were compared in 10 patients with FTD and 10 healthy older adults. Qualitative and quantitative measures of diagnostic equivalency were used to determine the diagnostic utility of ASL compared to FDG-PET. Sensitivity, specificity, and inter-rater reliability were calculated for each modality from scores of subjective visual ratings and from analysis of regional mean values in thirteen a priori regions of interest (ROI). To determine the extent of concordance between modalities in each patient, individual statistical maps generated from comparison of each patient to controls were compared between modalities using the Jaccard similarity index (JI). RESULTS: Visual assessments revealed lower sensitivity, specificity and inter-rater reliability for ASL (66.67%/62.12%/0.2) compared to FDG-PET (88.43%/90.91%/0.61). Across all regions, ASL performed lower than FDG-PET in discriminating patients from controls (areas under the receiver operating curve: ASL = 0.75 and FDG-PET = 0.87). In all patients, ASL identified patterns of reduced perfusion consistent with FTD, but areas of hypometabolism exceeded hypoperfused areas (group-mean JI = 0.30 ± 0.22). CONCLUSION: This pilot study demonstrated that ASL can detect similar spatial patterns of abnormalities in individual FTD patients compared to FDG-PET, but its sensitivity and specificity for discriminant diagnosis of a patient from healthy individuals remained unmatched to FDG-PET. Further studies at the individual level are required to confirm the clinical role of ASL in FTD management.

Pediatric gastrointestinal nuclear medicine.

General localization of gastrointestinal bleeding through the use of labeled red blood cells may be performed in children, or (99m)Tc-pertechnetate may be used if a Meckel's diverticulum is suspected. As in adults, cholecystitis and biliary leak may be assessed in children via (99m)Tc-IDA derivatives. Gastroesophageal reflux can be evaluated by oral consumption of the child's usual diet labeled with (99m)Tc sulfur colloid. For the scintigraphic determination of pulmonary aspiration, a relatively high concentration of tracer within a drop of liquid is placed beneath the child's tongue followed by dynamic imaging of the respiratory tract. Colonic transit scintigraphy can aid in the identification and therapeutic decision-making in patients with functional fecal retention, the most common cause of chronic constipation in children. (18)F-DOPA positron emission tomography is useful for classifying pancreatic involvement in infantile hyperinsulinism as focal or diffuse, thereby differentiating between patients who should receive curative focal pancreatic resection versus those who should receive medical management. Assessment of protein-losing enteropathy can be conducted scintigraphically and, compared with fecal alpha-1 antitrypsin collection, the scintigraphic method can detect esophageal and gastric protein loss. Also, scintigraphic quantification of protein loss can be performed without the requirement for fecal collection. Intestinal inflammation in children with inflammatory bowel disease can be evaluated using (99m)Tc white blood cells. The scintigraphic method is safe, accurate, well-tolerated by children and complementary to endoscopy in most patients.

Unsupervised boundary delineation of spinal neural foramina using a multi-feature and adaptive spectral segmentation.

As a common disease in the elderly, neural foramina stenosis (NFS) brings a significantly negative impact on the quality of life due to its symptoms including pain, disability, fall risk and depression. Accurate boundary delineation is essential to the clinical diagnosis and treatment of NFS. However, existing clinical routine is extremely tedious and inefficient due to the requirement of physicians' intensively manual delineation. Automated delineation is highly needed but faces big challenges from the complexity and variability in neural foramina images. In this paper, we propose a pure image-driven unsupervised boundary delineation framework for the automated neural foramina boundary delineation. This framework is based on a novel multi-feature and adaptive spectral segmentation (MFASS) algorithm. MFASS firstly utilizes the combination of region and edge features to generate reliable spectral features with a good separation between neural foramina and its surroundings, then estimates an optimal separation threshold for each individual image to separate neural foramina from its surroundings. This self-adjusted optimal separation threshold, estimated from spectral features, successfully overcome the diverse appearance and shape variations. With the robustness from the multi-feature fusion and the flexibility from the adaptively optimal separation threshold estimation, the proposed framework, based on MFASS, provides an automated and accurate boundary delineation. Validation was performed in 280 neural foramina MR images from 56 clinical subjects. Our method was benchmarked with manual boundary obtained by experienced physicians. Results demonstrate that the proposed method enjoys a high and stable consistency with experienced physicians (Dice: 90.58% ± 2.79%; SMAD: 0.5657 ± 0.1544 mm). Therefore, the proposed framework enables an efficient and accurate clinical tool in the diagnosis of neural foramina stenosis.

Long-term patency of endoscopically harvested radial arteries: from a randomized controlled trial.

OBJECTIVE: From 2005 to 2007, 119 patients were enrolled in a prospective randomized controlled trial comparing open and endoscopically harvested radial arteries for coronary artery bypass grafting. The objective of the current study was to compare graft patency between intervention groups at more than 5 years from the initial trial. We hypothesized that endoscopically harvested radial arteries would show equivalent patency to those conventionally harvested. METHODS: At 5 years or greater from their operation, all consenting patients underwent a single-day anatomic and functional cardiac assessment with coronary computed tomography angiography and sestamibi myocardial perfusion scanning. Medical Outcomes Study 36-Item Short-Form Health Surveys and Seattle Angina Questionnaires were completed to assess the overall quality of life. All patients had received calcium channel blocker therapy for at least 6 months postoperatively. RESULTS: The mean (SD) duration of follow-up was 79.2 (8.6) months for all patients. One death occurred within 30 days of coronary artery bypass grafting in each treatment group, and eight additional noncardiac deaths occurred during the study time frame. Of 119 patients, 66 consented to follow-up. Thirty-two had open radial artery harvest, and 34 had endoscopic radial artery harvest. At more than 5 years, there were 28 patent conventionally harvested radial arteries (87.5%) and 31 patent endoscopically harvested radial arteries (91.2%) (P = 0.705). Measured quality of life was comparable between groups. CONCLUSIONS: Endoscopic radial artery harvest is safe and effective when compared with open radial artery harvest, with excellent graft patency demonstrated at more than 5 years. Patency results are noninferior in endoscopic radial artery harvest.

Long-term angiographic follow-up of robotic-assisted coronary artery revascularization.

BACKGROUND: Robotic-assisted coronary artery bypass grafting (CABG) has been shown in short-term studies to increase patient satisfaction and to reduce surgical morbidity and recovery times. However, the long-term patency rate of robotic-assisted CABG is unknown. Therefore, the objective of this study was to assess the long-term patency rate of robotic-assisted coronary artery bypass grafts. METHODS: The study cohort included all patients who underwent robotic-assisted conduit dissection for CABG at London Health Sciences Centre between September 1999 and December 2003. These patients had selective graft patency assessment using cardiac catheterization or computed tomography angiography (CTA), or both, and stress myocardial perfusion scintigraphy (MPS) 5 to 10 years after surgery to evaluate graft patency and to give functional information on the hemodynamic significance of any graft stenosis. Patients also completed quality of life questionnaires. RESULTS: From a total of 160 patients who underwent robotic-assisted CABG, 82 eligible patients were followed with graft patency assessments for a mean period of 8 years±16.3 months. The patency rate of all robotic-assisted CABG grafts in this patient cohort was 92.7%. The patency rate of left internal thoracic artery grafts to the left anterior descending artery after robotic-assisted CABG in this patient cohort was 93.4%. Patients consistently attained high scores on quality of life questionnaires after surgery. CONCLUSIONS: The long-term patency rate of grafts after robotic-assisted CABG was 92.7% at a mean follow-up period of 95.8±16.3 months. Specifically, the patency rate of left internal thoracic artery grafts to the left anterior descending artery after robotic-assisted CABG was 93.4%.