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The effects of pharmacological interventions, exercise, and dietary supplements on extra-cardiac radioactivity in myocardial perfusion single-photon emission computed tomography imaging.
Molavipordanjani, S, Abedi, SM, Hosseinimehr, SJ, Fatahian, A, Mardanshahi, A
Nuclear medicine communications. 2020;(9):841-847
Abstract
Myocardial perfusion imaging (MPI) as an imaging modality plays a key role in the monitoring of patients with cardiovascular disease. MPI enables the assessment of cardiovascular disease, the effectiveness of therapy, and viable myocardial tissue. However, MPI suffers from some downfalls and limitations, which can influence its clinical applications. These limitations can arise from the patient's condition, equipment, or the actions of the technologist. In this review, we mainly focused on the different effective parameters on radioactivity uptake of organs including liver, intestines, stomach, and gall bladder and how they affect the quality of the acquired images in nuclear medicine. More importantly, we cover how different suggested medicines, foods and exercise alleviative this problem.
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Pulmonary perfusion by iodine subtraction maps CT angiography in acute pulmonary embolism: comparison with pulmonary perfusion SPECT (PASEP trial).
Dissaux, B, Le Floch, PY, Robin, P, Bourhis, D, Couturaud, F, Salaun, PY, Nonent, M, Le Roux, PY
European radiology. 2020;(9):4857-4864
Abstract
OBJECTIVE To assess the diagnostic accuracy of iodine map computed tomography pulmonary angiography (CTPA), for segment-based evaluation of lung perfusion in patients with acute pulmonary embolism (PE), using perfusion single-photon emission CT (SPECT) imaging as a reference standard. METHODS Thirty participants who have been diagnosed with acute pulmonary embolism on CTPA underwent perfusion SPECT/CT within 24 h. Perfusion SPECT and iodine map were independently interpreted by 2 nuclear medicine physicians and 2 radiologists. For both modalities, each segment was classified as normoperfused or hypoperfused, as defined by a perfusion defect of more than 25% of a segment. The primary end point was the diagnostic accuracy (sensitivity and specificity) of iodine map for segment-based evaluation of lung perfusion, using perfusion SPECT imaging as a reference standard. Following blinded interpretation, a retrospective explanatory analysis was performed to determine potential causes of misinterpretation. RESULTS The median time between CTPA with iodine maps and perfusion SPECT was 14 h (range 2-23 h). A total of 597 segments were analyzed. Sensitivity and specificity of iodine maps with CTPA for the detection of segmental perfusion defects were 231/284 = 81.3% (95% CI 76.4 to 85.4%) and 247/313 = 78.9% (95% CI 74.1 to 83.1%), respectively. In retrospect, false results were explained in 48.7%. CONCLUSION Iodine map CTPA showed promising results for the assessment of pulmonary perfusion in patients with acute PE, with sensitivity of 81.3% and specificity of 78.9%, respectively. Recognition of typical pitfalls such as atelectasis, fissures, or beam-hardening artifacts may further improve the accuracy of the test. KEY POINTS • Sensitivity and specificity of iodine subtraction maps for the detection of segmental perfusion defects were 81.3% (95% CI 76.4 to 85.4%) and 78.9% (95% CI 74.1 to 83.1%), respectively. • Recognition of typical pitfalls such as atelectasis, fissures, or beam-hardening artifacts may further improve the diagnostic accuracy of the test.
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3.
Intelligent Imaging: Radiomics and Artificial Neural Networks in Heart Failure.
Currie, G, Iqbal, B, Kiat, H
Journal of medical imaging and radiation sciences. 2019;(4):571-574
Abstract
BACKGROUND Our previous work with 123iodine meta-iodobenzylguanidine (123I-mIBG) radionuclide imaging among patients with cardiomyopathy reported limitations associated with the prognostic power of global parameters derived from planar imaging [1]. Employing multivariate analysis, we further showed the regional washout associated with territories adjacent to infarcted myocardium obtained from single-photon emission computed tomography imaging (SPECT) yielded superior prognostic power over the other planar and SPECT indices in predicting future cardiac events [1]. The aim of this study was to apply an artificial neural network (Neural Analyser version 2.9.5) to the original data from the same patient cohort to evaluate the most potent prognostic index for future cardiac events among patient with cardiomyopathy. METHODS The original data were reevaluated using an artificial neural network (Neural Analyser version 2.9.5). There were 84 input variables in the original 22 patients from clinical data, electrocardiogram (rest, stress, and continuous ambulatory electrocardiogram recording), transthoracic echocardiography, coronary angiogram, sestamibi myocardial perfusion SPECT, planar and SPECT 123I-mIBG, and genetic and biomarkers, detailed in the previous work. A single binary output was a cardiac event or no cardiac event in the follow-up period. RESULTS Following training and validation phases, the optimal number of inputs was determined to be two with a training loss of 0.025 and selection loss <0.001. The final architecture had inputs of a change in left ventricular ejection fraction (Δ > -10%) and 123I-mIBG planar global washout (>30%), two hidden layers of 6 and 1 node, respectively, and a binary output. Using receiver operator characteristics analysis demonstrated an area under the curve of 0.75 correlating to a sensitivity of 100% and specificity of 50%. CONCLUSION The premise that regional washout of 123I-mIBG SPECT from noninfarcted tissue is the best predictor of cardiac events was built on has a sound and logical foundation. By artificial neural network analysis; however, 123I-mIBG planar global washout of >30% was shown to be the best indicator for risk of cardiac event when accompanied by a decline in left ventricular ejection fraction of >10%. Further investigation should be undertaken assessing assimilation into big data and the potential for automated feature extraction from raw image datasets with convolutional neural networks.
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Assessment of Myocardial CZT SPECT Recording in a Forward-Leaning Bikerlike Position.
Perrin, M, Roch, V, Claudin, M, Verger, A, Boutley, H, Karcher, G, Baumann, C, Veran, N, Marie, PY, Imbert, L
Journal of nuclear medicine : official publication, Society of Nuclear Medicine. 2019;(6):824-829
Abstract
This prospective randomized study assessed myocardial perfusion imaging with the high-sensitivity D.SPECT cadmium-zinc-telluride camera in a forward-leaning bikerlike position, which may potentially lower diaphragmatic attenuation and reduce breathing-related cardiac motion, in a manner comparable to the prone position proposed with other SPECT cameras. Methods: Patients referred for a stress-rest 99mTc-sestamibi protocol and positioned in the biker position, with the chest leaning forward on the D.SPECT camera-head at 35° from vertical, had an additional resting D.SPECT recording in the supine position (n = 40) or in the sitting position with the back rearward at 30° from vertical (n = 40). Segments with attenuation artifacts were defined as those with less than 65% uptake but with strictly normal contractility at gated SPECT and no defect reversibility from stress images. Results: The biker position was associated with lower heart-to-detector distances than the supine or sitting positions (both P < 0.001); lower cardiac motion amplitudes, assessed on panograms, than the supine position (P < 0.001); and fewer segments with attenuation artifacts than the supine position (on average, 1.10 ± 1.01 vs. 1.90 ± 1.74, P = 0.010) or the sitting position (0.75 ± 0.93 vs. 1.38 ± 1.60, P = 0.011). Conclusion: Myocardial perfusion images from D.SPECT are enhanced for patients positioned in a forward-leaning bikerlike position comparatively to sitting or supine positions, with a notably lower rate of attenuation artifacts.
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Optimizing the Diagnosis of Parkinsonian Syndromes With 123I-Ioflupane Brain SPECT.
Banks, KP, Peacock, JG, Clemenshaw, MN, Kuo, PH
AJR. American journal of roentgenology. 2019;(2):243-253
Abstract
OBJECTIVE. The purpose of this article is to provide a review of 123I-ioflupane SPECT in the evaluation of suspected parkinsonian syndromes (PSs). This collection of diseases presents frequent diagnostic challenges, even by movement disorder and dementia specialists. CONCLUSION. The 123I-ioflupane scan serves as an imaging biomarker of the status of presynaptic dopamine transporters (DATs) in the striatum. As a result of neuronal death, DATs are greatly reduced in patients with PS neurodegenerative disorders, whereas clinical mimics generally do not show striatal DAT loss. This provides a tremendous opportunity for 123I-ioflupane to aid in the accurate and timely diagnosis of these patients and optimize their management.
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Neuroimaging Applications in Restless Legs Syndrome.
Rizzo, G, Plazzi, G
International review of neurobiology. 2018;:31-64
Abstract
Neuroimaging studies provide information useful to understand the pathophysiology of restless legs syndrome. Molecular PET and SPECT imaging findings mainly supported dysfunction of dopaminergic pathways involving not only the nigrostriatal but also mesolimbic pathways. Magnetic resonance imaging (MRI) studies have used different techniques. Studies using iron-sensitive sequences supported the presence of a regionally variable low brain iron content, mainly at the level of substantia nigra and thalamus. The search for brain structural or microstructural abnormalities by voxel-based morphometry, diffusion tensor imaging or cortical thickness analysis has reported none or variable findings in restless legs syndrome patients, most of them in regions belonging to sensorimotor and limbic/nociceptive networks. Functional MRI studies have substantially demonstrated activation or connectivity changes in the same networks. Magnetic resonance spectroscopy studies showed metabolic changes in the thalamus, which is a hub of these networks. In summary, neuroimaging findings in restless legs syndrome support the presence of reduction of brain iron content, of dysfunction of mesolimbic and nigrostriatal dopaminergic pathways, and of abnormalities at level of limbic/nociceptive and sensorimotor networks.
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Clinical imaging in dementia with Lewy bodies.
Surendranathan, A, O'Brien, JT
Evidence-based mental health. 2018;(2):61-65
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Abstract
Dementia with Lewy bodies (DLB) is a common neurodegenerative dementia in older people; however, the clinical features, particularly cognitive fluctuations and rapid eye movement sleep disorder, are often hard to elicit, leading to difficulty in making the diagnosis clinically. Here we examine the literature for the evidence behind imaging modalities that could assist in making the diagnosis. Dopamine transporter (DAT) imaging remains the best modality for differentiation from dementia of Alzheimer's type with high sensitivity and specificity reported based on pathological diagnoses. 123Iodine-metaiodobenzylguanidine myocardial scintigraphy (MIBG) however is rapidly becoming an alternative imaging modality for the diagnosis of DLB, though studies assessing its accuracy with postmortem verification are still awaited. However, there are suggestions that MIBG may be better in the differentiation of vascular parkinsonism from DLB than DAT scans but may have lower sensitivity for detecting DLB compared with the 80% sensitivity seen in DAT imaging. Structural MRI scans have long been used for the diagnosis of dementia; however, their utility in DLB is limited to revealing the presence of coexisting Alzheimer's disease. Fluorodeoxyglucose (FDG) PET is an alternative biomarker that can also differentiate Alzheimer's disease and DLB but lacks the evidence base of both DAT and MIBG scans.
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123I-ioflupane SPET and 123I-MIBG in the diagnosis of Parkinson's disease and parkinsonian disorders and in the differential diagnosis between Alzheimer's and Lewy's bodies dementias.
Nuvoli, S, Palumbo, B, Malaspina, S, Madeddu, G, Spanu, A
Hellenic journal of nuclear medicine. 2018;(1):60-68
Abstract
Nuclear medicine procedures are widely used as "in vivo" biomarkers in a large number of brain diseases, especially in the diagnosis of Parkinson's disease (PD) and of parkinsonian disorders (pD). Furthermore, nuclear medicine is used in the differential diagnosis of dementias especially Alzheimer's disease (AD) and dementia with Lewy's bodies (LBD) which share many clinical symptoms and often LBD is misdiagnosed as AD. The differential diagnosis between these clinical entities is crucial for treatment since LBD also shares some clinical symptoms with parkinsonian disorders. We reviewed the most relevant papers that study the usefulness of both iodine-123-ioflupane studied by single photon emission tomography (123I-ioflupane SPET) and of 123I-metaiodobenzylguanidine (123I-MIBG) cardiac scintigraphy in the diagnosis of PD and pD and in the differential diagnosis between AD and LBD in order to contribute to the clinical practice of the diseases.
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Hybrid SPECT/CT Imaging in the Management of Differentiated Thyroid Carcinoma.
Ahmed, N, Niyaz, K, Borakati, A, Marafi, F, Birk, R, Usmani, S
Asian Pacific journal of cancer prevention : APJCP. 2018;(2):303-308
Abstract
Differentiated thyroid cancer (DTC) has a good prognosis overall; however, lifelong follow-up is required for many cases. Radioiodine planar imaging with iodine-123 (I-123) or radioiodine-131 (I-131) remains the standard in the follow-up after initial surgery and ablation of residual thyroid tissue using I-131 therapy. Radioiodine imaging is also used in risk-stratifying and for staging of thyroid cancer, and in long-term follow-up. Unfortunately, the lack of anatomical detail on planar gamma camera imaging and superimposition of areas presenting with increased radioiodine uptake can make accurate diagnosis and localization of radioiodine-avid metastatic disease challenging, leading to false positive results and potentially to over-treatment of patients. Hybrid SPECT/CT allows precise anatomical localization and superior characterization of foci of increased tracer uptake when compared to planar imaging. This, in turn, allows the differentiation of pathological and physiological uptake, increasing the accuracy of image interpretation and ultimately improving the accuracy of DTC staging and subsequent patient management. In this review, we look at the unique and emerging role that SPECT/CT plays in the management of DTC, illustrated by examples from our own clinical practice.
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Low-dose dual-isotope procedure planed for myocardial perfusion CZT-SPECT and assessed through a head-to-head comparison with a conventional single-isotope protocol.
Imbert, L, Roch, V, Merlin, C, Djaballah, W, Cachin, F, Perrin, M, Claudin, M, Verger, A, Boutley, H, Karcher, G, et al
Journal of nuclear cardiology : official publication of the American Society of Nuclear Cardiology. 2018;(6):2016-2023
Abstract
PURPOSE OF THE REPORT This study aimed at assessing an original low-dose dual-isotope procedure in which the abnormal stress Tc-99m Sestamibi SPECT is followed by rest Tl-201 SPECT, along with a head-to-head comparison with a single-isotope procedure. METHODS AND RESULTS One hundred two patients, referred for a low-dose stress-SPECT with Sestamibi (123 ± 20 MBq) on a CZT camera and for whom a rest Sestamibi SPECT was warranted, had an additional Tl-201 rest-SPECT (52 ± 5 MBq) between stress and rest Sestamibi SPECT recordings. Tl-201 images were processed for spill-over and scatter corrections, and uptake differences with stress Sestamibi SPECT were analyzed: (1) for rest acquisitions from Tl-201 (dual-isotope procedure) and from Sestamibi (single-isotope procedure) and (2) in segments for which a diagnosis of ischemia, infarct, or normal perfusion was achieved. Mean effective dose was 8.3 mSv for dual-isotope but would decrease to 5.7 mSv for an expected rate of 37% of patients for whom rest-SPECT is not warranted. After a further background correction of Tl-201 images, the rest-stress difference in myocardial uptake was equivalent between dual- and single-procedures for identifying ischemic segments (respective areas-under-curves: 0.83 ± 0.03 and 0.81 ± 0.03). CONCLUSION This original dual-isotope procedure provides acceptable radiation doses and consistent results, as compared with conventional single-isotope.