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Background: Preoperative prediction of postoperative pulmonary function after anatomical resection for lung cancer is essential to prevent long-term morbidity and mortality. Here, we compared the accuracy of hybrid single-photon emission computed tomography/computed tomography (SPECT/CT) with traditional anatomical and planar scintigraphy approaches in predicting postoperative pulmonary function in patients with impaired lung function. Methods: We analyzed the predicted postoperative pulmonary function in patients undergoing major anatomical lung resection, applying a segment counting approach, planar perfusion scintigraphy (PPS), and SPECT/CT-based lung function quantification. Results: In total, 120 patients were evaluated, of whom 82 were included in the study. Postoperative lung function tests were obtained in 21 of 82 patients. The preoperative SPECT/CT-based quantification yielded very accurate results compared to the actual postoperative FEV1 and DLCO values. The linear regression analysis showed that the SPECT/CT-based analysis predicted postoperative FEV1 (%) and DLCO values more accurately than the segment counting approach or PPS. Accordingly, 58/82 patients would qualify for anatomical lung resection according to the SPECT-based quantification, 56/82 qualified according to the PPS (Mende), and only 47/82 qualified according to the segment counting method. Moreover, we noted that the SPECT-predicted FEV1 values were very close to the actual postoperative values in emphysema patients, and selected patients even showed improved lung function after surgery. Conclusions: Anatomically driven methods such as SPECT/CT yielded a very accurate prediction of the postoperative pulmonary function. Accordingly, applying SPECT/CT revealed more patients who would formally qualify for lung resection. We suggest SPECT/CT as the preferred method to evaluate eligibility for lung surgery in selected patients with impaired pulmonary reserve. [ABSTRACT FROM AUTHOR]

IntroductionAlthough most cases of myocardial bridge (MB) are clinically benign, sometimes it can be one of potential threats of myocardial infarction (MI) and life-threatening arrhythmia. In the present study, we present a case of ST-segment elevation MI caused by MB and concomitant vasospasm.Case PresentationA 52-year-old woman was brought to our tertiary hospital due to resuscitated cardiac arrest. Because the 12-lead electrocardiogram indicated ST-segment elevation MI, coronary angiogram was promptly commenced, which showed near-total occlusion at the middle portion of left anterior descending coronary artery (LAD). After intracoronary nitroglycerin administration, this occlusion was dramatically relieved, however, systolic compression at this site remained, indicative of myocardial bridge (MB). Intravascular ultrasound also showed eccentric compression with a “half-moon” sign, which is consistent with MB. Coronary computed tomography also showed a bridged coronary segment surrounded by myocardium at the middle portion of LAD. To assess the severity and extent of myocardial damages and ischemia, myocardial single photon emission computed tomography (SPECT) was additionally conducted, showing a moderate fixed perfusion defect around the cardiac apex, suggesting MI. After receiving optimal medical therapy, the patient's clinical symptoms and signs were improved then the patient was discharged from the hospital successfully and uneventfully.ConclusionWe demonstrated a case of MB-induced ST-segment elevation MI which was confirmed with its perfusion defects via myocardial perfusion SPECT. There have been proposed a number of diagnostic modalities to examine its anatomic and physiologic significance. Among them, myocardial perfusion SPECT can be available as one of useful modalities to evaluate the severity and extent of myocardial ischemia in patients with MB.

Nuclear imaging plays an important role in the diagnostic path of patients with unilateral condylar hyperplasia (UCH). The purpose of this study was to determine the performance of single-photon emission computed tomography–computed tomography (SPECT–CT) in a large group of patients with suspected UCH. This study prospectively included 156 patients with a clinical presentation of progressive mandibular asymmetry. All patients underwent 99 mTc-HDP SPECT–CT and extensive baseline and follow-up documentation. The relative activity of the ipsilateral condyle in relation to the contralateral condyle was calculated for both the mean and maximum count, and the diagnostic accuracy of different cut-off values was determined. The area under the receiver operating characteristic curve of the SPECT–CT scan was 0.892 for the mean count and 0.873 for the maximum count. The optimal cut-off of> 8% (SPECT–CT mean count) resulted in a sensitivity of 87.0% and a specificity of 88.6%. SPECT–CT showed good diagnostic performance in UCH; however the benefit of the CT scan is questionable and the potential disadvantages have to be weighed against the benefits when compared to standard SPECT scanning. When using SPECT–CT in the diagnostic path in UCH, a mean value cut-off of>8% for the relative activity between the condyles is most accurate. [ABSTRACT FROM AUTHOR]

Parkinson's disease (PD) is a progressive neurodegenerative disorder caused by the loss of dopamine, an important neurotransmitter involved in regulating movement. Nuclear medicine imaging methods such as single‐photon emission computed tomography (SPECT) combined with radiotracers can obtain the density of this neurotransmitter. This reduced density leads to classic PD symptoms, such as bradykinesia, tremor and stiffness, consequently affecting walking and postural control. The aim of this study was to verify the correlation between disorders of gait kinematics and postural instability with dopamine depletion in individuals with mild to moderate PD. This is a descriptive, observational cross‐sectional study. Subjects were assessed for spatiotemporal gait parameters by a three‐dimensional motion capture system, for postural control by stabilometry on a force plate. Dopamine depletion was verified through 99mTc‐TRODAT‐1 (SPECT‐CT) examination. The subjects were in the off‐stage of levodopa in all analysis. We evaluated 71 individuals, 32 with mild to moderate PD (HY 2 and 2.5) and 39 healthy individuals matched for gender, age, and height. There was a significant difference between the groups regarding the spatiotemporal variables of gait, as well as in the stabilometric variables. However, there was no correlation between these disturbances and the uptake values of 99mTc‐TRODAT‐1. The results indicate that there is no correlation between gait impairments and postural instability of individuals with mild to moderate PD and the dopaminergic depletion measured through the 99mTc‐TRODAT‐1 (SPECT‐CT). [ABSTRACT FROM AUTHOR]

Background: Iterative computed tomography (CT) image reconstruction shows high potential for the preservation of image quality in diagnostic CT while reducing patients' exposure; it has become available for low-dose CT (LD-CT) in high-end hybrid imaging systems (e.g. single-photon emission computed tomography [SPECT]-CT). Purpose: To examine the effect of an iterative CTreconstruction algorithm on image quality, image noise, detectability, and the reader's confidence for LD-CT data by a subjective assessment. Material and Methods: The LD-CT data were validated for 40 patients examined by an abdominal hybrid SPECT-CT (U=120 kV, I=40 mA, pitch=1.375). LD-CT was reconstructed using either filtered back projection (FBP) or an iterative image reconstruction algorithm (Adaptive Statistical Iterative Reconstruction [ASIR]VR) with different parameters (ASIR levels 50% and 100%). The data were validated by two independent blinded readers using a scoring system for image quality, image noise, detectability, and reader confidence, for a predefined set of 16 anatomic substructures. Results: The image quality was significantly improved by iterative reconstruction of the LD-CT data compared with FBP (P≥0.0001). While detectability increased in only 2/16 structures (P≥0.03), the reader's confidence increased significantly due to iterative reconstruction (P≥0.002). Meanwhile, at the ASIR level of 100%, the detectability in bone structure was highly reduced (P=0.003). Conclusion: An ASIR level of 50% represents a good compromise in abdominal LD-CT image reconstruction. The specific ASIR level improved image quality (reduced image noise) and reader confidence, while preserving detectability of bone structure. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the differences of bone tracer uptake (BTU) in symptomatic and asymptomatic contralateral knees in patients after reconstruction of the anterior cruciate ligament (ACL-R) and to identify typical BTU patterns and threshold values to differentiate pathological from physiological BTU.Methods: 53 patients after unilateral ACL-R were retrospectively included in the study. The population was subdivided into a group of symptomatic operated knees and a group of contralateral asymptomatic non-operated knees. BTU was measured in SPECT/CT using a validated anatomical localization-scheme and normalized mean BTU values were calculated in both knees. Wilcoxon signed rank-test and Pearson's rank-correlation coefficient were used (p < 0.05).Results: Symptomatic knees after ACL-R showed significantly more BTU than asymptomatic ones (p < 0.01).Based on the measured BTU activity in SPECT/CT in symptomatic operated and asymptomatic non-operated knees, intensity thresholds of pathological BTU were established. A BTU threshold of greater than the Median + 1 SD of the asymptomatic non-operated knee was defined as pathological. In both groups the highest mean BTU was found on the femoral, tibial and patellar articular surfaces, the lowest BTU in femoral and tibial regions far from the joint.Conclusions: The established BTU thresholds for SPECT/CT in knees after ACL-R help to differentiate disease-specific from patient-specific BTU. It could be speculated that BTU in asymptomatic knees equates to the preoperative condition of the knee joint before ACL-R. Therefore, the results of this study help to understand in-vivo loading of the knee and ultimately lead to prediction of development of osteoarthritis in an early stage. [ABSTRACT FROM AUTHOR]

Injuries of the lumbar neural arch, in particular the pars interarticularis, are widely considered to be due to abnormal bone stress secondary to repetitive loading/shearing, and are a common pathology and a main cause of lower back pain in elite athletes across a range of sports. Medical imaging plays a pivotal role in the diagnosis, monitoring and prognostication of neural arch injury. Early detection is highly desirable in the young elite athlete, as early injuries have been shown to require shorter recovery time and have a higher potential of full healing, whilst accurate grading of injury allows appropriate rehabilitation planning. Various imaging modalities are used in the diagnosis and management of pars stress injury, each with their strengths and weaknesses. There is currently a lack of general consensus over the most appropriate imaging pathway for neural arch injury in this specific group of patients. In this review article, we present an overview of neural arch injury, the various imaging modalities used and their imaging appearances with a brief pictorial review, and a proposed imaging algorithm with special considerations in the young elite athletes. [ABSTRACT FROM AUTHOR]

Objective(s): The objective of this study was to evaluate the performance and utility of 99mTc HYNIC-TOC planar scintigraphy and SPECT/CT in the diagnosis, staging and management of gastroenteropancreatic neuroendocrine tumors (GPNETs). Methods: 22 patients (median age, 46 years) with histologically proven gastroentero-pancreatic NETs underwent 99mTc HYNIC-TOC whole body scintigraphy and regional SPECT/CT as indicated. Scanning was performed after injection of 370-550 MBq (10-15 mCi) of 99mTc HYNIC-TOC intravenously. Images were evaluated by two experienced nuclear medicine physicians both qualitatively as well as semi quantitatively (tumor to background and tumor to normal liver ratios on SPECT -CT images). Results of SPECT/CT were compared with the results of conventional imaging. Histopathology results and follow-up somatostatin receptor scintigraphy with 99mTc HYNIC TOC or conventional imaging with biochemical markers were considered to be the reference standards. Results: 99mTc HYNIC TOC showed sensitivity and specificity of 87.5% and 85.7%, respectively, for primary tumor and 100% and 86% for metastases. It was better than conventional imaging modalities for the detection of both primary tumor (P

Nuclear medicine imaging is widely used in pain medicine. Low back pain is commonly encountered by physicians, with its prevalence from 49% to 70%. Computed tomography (CT) or magnetic resonance imaging (MRI) are usually used to evaluate the cause of low back pain, however, these findings from these scans could also be observed in asymptomatic patients. Bone scintigraphy has an additional value in patients with low back pain. Complex regional pain syndrome (CRPS) is defined as a painful disorder of the extremities, which is characterized by sensory, autonomic, vasomotor, and trophic disturbances. To assist the diagnosis of CRPS, three-phase bone scintigraphy is thought to be superior compared to other modalities, and could be used to rule out CRPS due to its high specificity. Studies regarding the effect of bone scintigraphy in patients with extremity pain have not been widely conducted. Ultrasound, CT and MRI are widely used imaging modalities for evaluating extremity pain. However, SPECT/CT has an additional role in assessing pain in the extremities. [ABSTRACT FROM AUTHOR]

Carcinoid tumors are relatively rare and can occur in the thorax, abdomen, or pelvis. Functional imaging in the form of Indium-111 pentetreotide scanning is widely used for identification of these tumors and it exploits the fact that the vast majority of these tumors express somatostatin receptors on their cell membrane. In this report, we present a case of a 76-year-old man who was diagnosed with peritoneal carcinomatosis. The findings of the initial imaging made by planar and single photon emission computed tomography were misleading and the actual diagnosis was only made by single photon emission computed tomography/computed tomography.

The Cardiac syndrome X includes patients, mainly women, with the triad of angina pectoris, a positive exercise electrocardiogram for myocardial ischemia and angiographically smooth coronary arteries. The most common manifested clinical symptom in those patients is chest pain. In most cases, the syndrome is associated with debilitating symptomology, increased psychological morbidity and a poor quality of life. All the heterogeneity of the syndrome makes the treatment approaches to those patients unclear and uncertain.

Objectives: To evaluate the incremental diagnostic value of iodine-131 single-photon emission computed tomography/computed tomography (131I SPECT-CT) compared to planar scintigraphy in patients with differentiated thyroid carcinoma (DTC). Materials and Methods: The study group consisted of 117 patients (Age group = 7-81 yrs; 70 females, 47 males) with DTC; post total thyroidectomy. A diagnostic dose of 111 Mbq (3 mCi) 131I was administered and planar scan obtained after 48 hrs. Foci of uptake in planar scan were classified as thyroid remnants, lymph nodes, lung metastases, skeletal metastases, distant metastases or of indeterminate etiology. Single-photon emission computed tomography/computed tomography (SPECT-CT) of these areas was then acquired on a dual head gamma camera and reclassification was done. Results: Planar scans depicted 218 foci of 131I activity classified as 194 neck foci and 24 distant foci. Incremental value of SPECT/CT compared with planar imaging was found for 72 of 194 neck lesions (37.1%) and 24 of 24 distant foci (100%) for a total of 95 of 218 iodine avid foci (44%). SPECT/CT findings led to down staging of 44 of the 72 foci from equivocal or lymph nodes to thyroid remnant and upstaging of 18 of the 72 foci from equivocal or thyroid remnant to lymph node involvement. An additional 8 of the 72 foci were reclassified as physiologic dental or salivary gland activity. The remaining 2 of the 72 foci was found out to be contamination on patient's skin. Conclusion: 131I SPECT-CT provides increased diagnostic information compared with planar imaging alone, which may alter the patient management. [ABSTRACT FROM AUTHOR]

Bone scintigraphy is widely used for the detection of skeletal metastases, particularly in prostate and breast cancer. Although planar imaging is widely used, single-photon emission computed tomography (SPECT) imaging has demonstrated higher sensitivity. SPECT/CT imaging with the integration of CT and SPECT gantries has enhanced bone scintigraphy by providing accurate lesion localization and characterization of equivocal and solitary bone lesions. The key impact has been enhanced diagnostic confidence in the differentiation of benign from malignant skeletal lesions made possible by accurate localization of lesions to facet joints, vertebral bodies, or pedicles due to the exact coregistration of CT and SPECT as well as consideration of sclerosis or lysis within the lesion seen on CT. Several studies comparing planar, SPECT, and SPECT/CT in equivocal lesions have demonstrated a substantial improvement in specificity with SPECT/CT. This review highlights the key studies demonstrating the value of SPECT/CT in the evaluation of skeletalmalignancies and shows clinical examples illustrating the impact of SPECT/CT in improved localization and characterization of skeletal lesions. [ABSTRACT FROM AUTHOR]

The article discusses a study which aims to evaluate the utility of hydrazinonicotinyl- Tyr3-octreotide (HYNIC-TOC) planar scintigraphy in the diagnosis and management of gastroenteropancreatic neuroendocrine tumors (GPNETs). The study involves 22 patients who were given injection of HYNIC-TOC intravenously and their computed tomography (CT) results were compared with the results of conventional imaging. Further the study reveals that HYNIC-TOC scintigraphy is better for GPNETs detection.

The aging population highlights the importance of early diagnosis of neurodegenerative diseases in the elderly. Current diagnoses of such diseases rely on visual assessment of the neuron activity of the specific regions in the brain revealed by SPECT imaging with a specific tracer, 99mTc-TRODAT-1. However, due to the difficulties in defining the regions of interest (ROI) in SPECT images, efficient indices are lacking for quantitative analysis. In this study, we performed simultaneous CT and SPECT scans and used the CT images as the medium to register the MR and SPECT images, such that the ROI delineated in the MR image can be mapped onto the SPECT image in the corresponding area. A robust registration scheme is proposed, including coarse registration using principal axes alignment and then fine-tuning the registration using a combination of maximal cross-section area detection and the general Hough transform. The results from three clinical datasets all show improved accuracy of registration as compared with the results obtained using conventional principal axes alignment alone. Based on these registration results, a correct ROI can be defined in the SPECT images and ROI-based quantitative indices can be further derived. [ABSTRACT FROM AUTHOR]

Abstract: Functional imaging techniques in nuclear medicine provide crucial diagnostic information in a variety of clinical settings that are encountered regularly in orthopaedic practice. It is important that the orthopaedic surgeon is aware of the modalities on offer and appreciates the relative strengths and limitations of these techniques. This article will describe the physical principles underlying nuclear medicine imaging with single-photon and positron-emitting radiotracers. It will then go on to illustrate the clinical applications of these techniques as applied to pathological conditions of the bone, with particular emphasis on bone scintigraphy and hybrid imaging techniques, such as single-photon emission computed tomography/computed tomography (SPECT/CT) and positron emission tomography/computed tomography (PET/CT). [Copyright &y& Elsevier]

Carcinoid tumors are relatively rare and can occur in the thorax, abdomen, or pelvis. Functional imaging in the form of Indium-111 pentetreotide scanning is widely used for identification of these tumors and it exploits the fact that the vast majority of these tumors express somatostatin receptors on their cell membrane. In this report, we present a case of a 76-year-old man who was diagnosed with peritoneal carcinomatosis. The findings of the initial imaging made by planar and single proton emission computed tomography were misleading and the actual diagnosis was only made by single proton emission computed tomography/computed tomography. [ABSTRACT FROM AUTHOR]

Purpose: To compare the reliability and accuracy of the pre-treatment dosimetry predictions using cone-beam computed tomography (CBCT) versus 99m Tc-labeled macroaggregated albumin (MAA) SPECT/CT for perfused volume segmentation in patients with hepatocellular carcinoma treated by selective internal radiation therapy (SIRT) using 90 Y-glass microspheres., Materials and Methods: Fifteen patients (8 men, 7 women) with a mean age of 68.3±10.5 (SD) years (range: 47-82 years) who underwent a total of 17 SIRT procedures using 90 Y-glass microspheres for unresectable hepatocellular carcinoma were retrospectively included. Pre-treatment dosimetry data were calculated from 99m Tc-MAA SPECT/CT using either CBCT or 99m Tc-MAA SPECT/CT to segment the perfused volumes. Post-treatment dosimetry data were calculated using 90 Y imaging (SPECT/CT or PET/CT). The whole liver, non-tumoral liver, and tumor volumes were segmented on CT or MRI data. The mean absorbed doses of the tumor (D T ), non-tumoral liver, perfused liver (D PL ) and perfused non-tumoral liver were calculated. Intra- and interobserver reliabilities were investigated by calculating Lin's concordant correlation coefficients (ρ c values). The differences (biases) between pre- and post-treatment dosimetry data were assessed using the modified Bland-Altman method (for non-normally distributed variables), and systematic bias was evaluated using Passing-Bablok regression., Results: The intra- and interobserver reliabilities were good-to-excellent (ρ c : 0.80-0.99) for all measures using both methods. Compared with 90Y imaging, the median differences were 5.8Gy (IQR: -12.7; 16.1) and 5.6Gy (IQR: -13.6; 10.2) for D PL -CBCT and D PL - 99m Tc-MAA SPECT/CT, respectively. The median differences were 1.6Gy (IQR: -29; 7.53) and 9.8Gy (IQR: -28.4; 19.9) for D T -CBCT and D T - 99m Tc-MAA SPECT/CT respectively. Passing-Bablok regression analysis showed that both CBCT and 99m Tc-MAA SPECT/CT had proportional biases and thus tendencies to overestimate D T and D PL at higher post-treatment doses., Conclusion: CBCT may be a reliable segmentation method, but it does not significantly increase the accuracy of dose prediction compared with that of 99m Tc-MAA SPECT/CT. At higher doses both methods tend to overestimate the doses to tumors and perfused livers., (Copyright © 2020 Soci showét showé françaises de radiologie. Published by Elsevier Masson SAS. All rights reserved.)

Introduction: We recently reported six cases of pulmonary/hilar malignancies as the result of incidental findings (IF) on CT attenuation correction (CTAC) during Single Photon Emission Computed Tomography Myocardial Perfusion Imaging (SPECT-CT MPI). In this study, clinical features, diagnostic procedures, and clinical outcomes were examined on all patients who had malignancies or significant IF that required further follow-up., Methods: Of 1,098 consecutive patients who underwent cardiac SPECT-CT MPI from September 1, 2017 to August 31, 2018, their MPI and CTAC were reviewed contemporaneously. Patients with known history of prior pulmonary or chest malignancy were excluded., Results: A total of 79 (7.2%) patients were identified to have significant IF on CTAC. After diagnostic CT, 47 patients had significant findings that warranted further follow-up and included in this study. Eight of 1,098 patients (0.73%) and 8/79 patients (10.1%) were found to have malignancy of the chest because of IF on the CTAC. There were no statistically significant differences in baseline characteristics and cancer risk factors among patients who had cancer versus those without. At the time of diagnosis, four patients had cancer at an advanced stage, resulting in death within 12 months. Three others had early stage lung cancer and one had mantle cell lymphoma; they were alive at a mean follow-up of 17.5+/-2.1 months. Biopsy for tissue diagnosis was performed safely with needle biopsy. Major complication occurred in one patient (1/9 or 11.1%) with needle biopsy; none with surgical biopsy., Conclusion: This study underscored the importance of reviewing CTAC images obtained during cardiac SPECT-CT MPI to detect clinically important IF., (© 2020 The University of Kansas Medical Center.)

Aims and Objectives: Currently the triple technique (including preoperative SLN imaging using SPECT CT after radioactive colloid injection; intraoperative injection of blue dye; and intraoperative usage of hand held gamma probe) has been demonstrated to be most accurate for the identification of Sentinel lymph node (SLN). However the availability of nuclear medicine department for SLN imaging is one of the major barriers in the diffusion of SLNB technology. The purpose of this study was to investigate whether the SLN detection rate using the intraoperative dual mapping (radioactive colloid + methylene blue dye) technique is comparable to the triple technique in a prospective trial. Methods: This prospective trial was started in the department of breast and gynecology oncology in collaboration with department of nuclear medicine at Amrita Institute of Medical Sciences, Kochi, Kerala in May 2017. Intraoperative dual SLN mapping technique consisted of subareolar injection of technetium 99m- labelled filtered sulphur colloid (15-37 MBq) and 3ml of 1% isosulphan blue dye just after anaesthetic induction followed by locating and dissecting the SLN using hand held gamma probe and blue dye. Triple technique consisted of subareolar injection of radioactive colloid followed by SPECT CT preoperatively; subareolar injection of blue dye intraoperatively; locating and dissection of SLN using gamma probe and blue dye. SLN biopsies (SLNBs) or complete axillary dissections were carried out, and SLNs identified during these procedures were classified as containing both blue dye and radioactivity ("blue-hot" nodes), radioactivity alone ("hot-only" nodes), or blue dye alone ("blue-only" nodes). Cases were categorized and tabulated based on the presence or absence of these three types of SLNs. Endpoint measured was the overall SLN detection rates and were compared between the two techniques. Results: Out of total 375 SLNBs done, 203 were done using triple technique and 41 using dual technique. SLN detection rates with intraoperative dual mapping technique was 100%, while that of triple technique of SLN identification was 97.6% (p = 0.216). We looked into the SLN detection rate of the individual procedures of the two techniques (triple versus dual technique): SLN detection rate of preoperative imaging using SPECT CT after radioactive dye injection was 100% in triple technique (procedure not performed in dual technique); SLN detection rate of intraoperative injection of blue dye ("blue" node) was 76% in both the techniques; SLN detection rate of "hot" nodes with the gamma probe was 94.5% in triple and 99% in dual technique; and the SLN detection rate of "hot and blue" nodes was 96.7% in triple and 100% in dual technique. Using either technique the SLN location was in axilla in 100% of cases. In 100% cases the surgical approach for SLN biopsy remained same. Conclusion: SLN detection rate of intraoperative dual technique was equivalent to the SLN detection rate of triple technique. Thereby in low resource settings where SPECT CT imaging is not possible in vicinity, the sentinel lymph node biopsy can still be performed by procuring the radioactive colloid (from outside centre) and blue dye and the hand held gamma probe. [ABSTRACT FROM AUTHOR]

Nuclear medicine imaging is widely used in pain medicine. Low back pain is commonly encountered by physicians, with its prevalence from 49% to 70%. Computed tomography (CT) or magnetic resonance imaging (MRI) are usually used to evaluate the cause of low back pain, however, these findings from these scans could also be observed in asymptomatic patients. Bone scintigraphy has an additional value in patients with low back pain. Complex regional pain syndrome (CRPS) is defined as a painful disorder of the extremities, which is characterized by sensory, autonomic, vasomotor, and trophic disturbances. To assist the diagnosis of CRPS, three-phase bone scintigraphy is thought to be superior compared to other modalities, and could be used to rule out CRPS due to its high specificity. Studies regarding the effect of bone scintigraphy in patients with extremity pain have not been widely conducted. Ultrasound, CT and MRI are widely used imaging modalities for evaluating extremity pain. However, SPECT/CT has an additional role in assessing pain in the extremities.

Purpose: Authors' goal is to evaluate the performance of simultaneous 99mTc-MDP/123I-MIBG tumor imaging with fast Monte-Carlo (MC) based joint iterative reconstruction as compared to sequential 99mTc-MDP and 123I-MIBG tumor imaging. Methods: Noise-free 99mTc and 123I SPECT projections were acquired separately using an anthropomorphic torso phantom modified to include a fillable tube around the lungs to mimic ribs. Additionally, 99mTc and 123I projections were acquired separately using a 1-cm spherical 'tumor' placed at various distances from one detector. Tumor-present data were generated by adding tumor projections to the torso phantom data, which were scaled to the total counts in typical clinical studies. Twenty-five noise realizations were generated by adding Poisson noise to the projection data for each radionuclide. Dual-radionuclide data were synthesized by summing the 99mTc and 123I projections. Image reconstruction was performed using: (1) SR-OSEM, ordered subset expectation maximization (OSEM) without scatter correction (SC) using single-radionuclide (SR) data; (2) SR-MC-OSEM, OSEM with a fast MC-based SC using SR data; (3) DR-OSEM, OSEM without SC using dual-radionuclide (DR) data; and (4) DR-MC-JOSEM, joint OSEM with a fast MC-based SC using DR data. Ten 99mTc-MDP and ten 123I-MIBG data sets, which had tumors mathematically inserted, were also used to evaluate the performance of authors' approach. For the phantom study, relative bias and relative standard deviation of tumor uptake were computed for each tumor using the tumor uptake in the noise-free single-radionuclide images, which were reconstructed by SR-MC-OSEM, as the gold standard. For both the phantom and constructed patient studies, mean contrast and standard deviation of contrast were computed for each tumor for both the single- and dual-radionuclide images. Additionally, contrast recovery was computed as the ratio between mean contrast and the mean contrast for SR-MC-OSEM. Results: For the phantom study, DR-MC-JOSEM yielded 2.7% on average relative bias of tumor uptake using the images, which were reconstructed from the noise-free SR data with SR-MC-OSEM, as the gold-standard. For both the phantom and constructed patient studies, DR-MC-JOSEM yielded 94.7% and 95.2% tumor contrast recovery on average using SR-MC-OSEM as the reference, in the phantom and constructed patient studies, respectively. DR-MC-JOSEM yielded comparable relative standard deviation of bias and standard deviation of contrast to SR-MC-OSEM. Conclusions: Simultaneous 99mTc-MDP/123I-MIBG tumor imaging using authors' dual-radionuclide reconstruction approach yielded comparable image quality to sequential 99mTc-MDP and 123I-MIBG imaging. For patients who need to undergo both scans, authors' approach offers perfectly registered dual-tracer images under identical conditions without compromising image quality, and reduces the imaging cost while increasing patient throughput. [ABSTRACT FROM AUTHOR]

Objectives: To study the vascularity and bone metabolism of the femoral head/neck following hip resurfacing arthroplasty, and to use these results to compare the posterior and the trochanteric-flip approaches., Methods: In our previous work, we reported changes to intra-operative blood flow during hip resurfacing arthroplasty comparing two surgical approaches. In this study, we report the vascularity and the metabolic bone function in the proximal femur in these same patients at one year after the surgery. Vascularity and bone function was assessed using scintigraphic techniques. Of the 13 patients who agreed to take part, eight had their arthroplasty through a posterior approach and five through a trochanteric-flip approach., Results: One year after surgery, we found no difference in the vascularity (vascular phase) and metabolic bone function (delayed phase) at the junction of the femoral head/neck between the two groups of patients. Higher radiopharmaceutical uptake was found in the region of the greater trochanter in the trochanteric-flip group, related to the healing osteotomy., Conclusions: Our findings using scintigraphic techniques suggest that the greater intra-operative reduction in blood flow to the junction of the femoral head/neck, which is seen with the posterior approach compared with trochanteric flip, does not result in any difference in vascularity or metabolic bone function one year after surgery.