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Comprehension of the typical distribution pattern of 99mTc‑methylenediphosphonate (MDP) is crucial for precise interpretation of bone scintigraphy. The presence of nonskeletal activity is predominantly confined to the kidneys and bladder, attributed to the standard renal excretion of 99mTc‑MDP. We discuss a 70‑year‑old woman with a known case of brucellosis using rifampin, doxycycline, trimethoprim/sulfamethoxazole (co‑trimoxazole), and ciprofloxacin for the past 8 months. Anterior and posterior aspects of the whole‑body bone scan showed diffuse increased uptake in the bodies of L2 and L3 vertebrae and related intervertebral disks. However, unexpected uptake is noted in the right upper quadrant in the region of the gallbladder. Radiochemical impurities did not show during radiopharmaceutical (MDP) quality control, and the other patients showed normal distribution. This gallbladder uptake may be attributed to the altered distribution of the radiotracer and/or gallbladder injury caused by the administration of antibiotic therapy. [ABSTRACT FROM AUTHOR]

Purpose: This study aimed to assess the agreement between the Thai cardiovascular (CV) risk score or pretest probability (PTP), and myocardial perfusion imaging (MPI), and to explore the association between abnormal MPI results and higher Thai CV risk scores or PTP risk. Materials and Methods: The study was conducted between March 2017 and December 2021, and included 128 patients. Myocardial perfusion gated single photon emission computed tomography imaging was performed on all patients, and agreement between the Thai CV risk score, PTP, and MPI was measured using weighted Cohen's kappa statistic. Logistic regression was used to calculate odds ratios (OR) and explore the association. Results: Fair agreement was observed between MPI and the Thai CV risk score (κ =0.269, P = 0.010), including patients with clinical chest pain (κ =0.367, P < 0.001). Subgroup analysis of patients with intermediate PTP revealed moderate agreement between MPI and the Thai CV risk score (κ =0.428, P = 0.002). Patients with intermediate (OR = 3.25, P = 0.010) or high (OR = 4.78, P = 0.001) Thai CV risk scores had significantly higher odds of having intermediate or high MPI results compared to those with low Thai CV risk scores. Conclusion: This study highlights the agreement between MPI and the Thai CV risk score and PTP. Higher Thai CV risk scores are associated with increased odds of abnormal MPI results. These findings provide valuable insights for clinical decision-making and patient management. [ABSTRACT FROM AUTHOR]

Malignant otitis externa (MOE) with skull base osteomyelitis (SBO) is an aggressive infection that predominantly affects elderly, diabetic, or immunocompromised patients, and is associated with high disease-specific mortality. Pseudomonas aeruginosa is the most isolated microorganism. External otitis associated with granulation tissue and pain is the most common presenting feature; a biopsy is obtained to rule out malignancy. A proper consensus is lacking regarding the best imaging modality for early initial diagnosis and follow-up. 99mTechnetium (99mTc)-labeled ubiquicidin (UBI) 29-41 is a bacterial attaching peptide that does not bind to activated leukocytes. We report a case of SBO initially misdiagnosed as a chronic otitis media, but later proved to be a case of MOE. 99mTc methylene diphosphonate bone scan and 99mTc-UBI 29-41 scan with single-photon emission computed tomography/computed tomography scans were performed to corroborate the clinical diagnosis. SBO remains a great challenge due to its increasing prevalence and high morbidity are difficult to diagnose and are often confused with cholesteatoma and neoplastic process. The UBI scan could be an auxiliary noninvasive diagnostic alternative in early diagnosis. [ABSTRACT FROM AUTHOR]

Introduction: Successful surgical treatment for primary hyperparathyroidism requires accurate localization of abnormal parathyroid tissue in terms of location and number. Imaging is important for localizing the parathyroid adenoma, and there has been significant interest in 18F-fluorocholine (FCH) positron emission tomography/computed tomography (PET/CT) for this purpose. Aim: This study attempted to ascertain the utility of 18F-FCH PET/CT as a first-line investigation in preoperative localization of abnormal parathyroid tissue in primary hyperparathyroidism, in comparison with 99mTc-sestamibi dual-phase scintigraphy with early single-photon emission computed tomography (SPECT)/CT and neck ultrasonography. Materials and Methods: Fifty-five patients with biochemical features of primary hyperparathyroidism were enrolled in this study. They underwent neck ultrasonography, 99mTc-sestamibi dual-phase scintigraphy with early SPECT/CT, and 18F-FCH PET/CT for localization of parathyroid lesions. Thirty-three patients underwent surgical resection of the detected lesions. For two patients, clinical and biochemical follow-up was used as a gold standard. Results: A total of 40 lesions were resected in the 33 patients who underwent surgery. A further two lesions were localized in two patients with clinical and biochemical follow-up as the gold standard. Of these 42 lesions, 41 were detected in preoperative imaging and 1 lesion was noted intraoperatively and resected. 41/42 lesions were detected by 18F-FCH PET/CT (detection rate: 97.6%), 33/42 by 99mTc-sestamibi dual-phase scintigraphy with early SPECT/CT (detection rate: 78.5%), and 30/42 by neck ultrasonography (detection rate: 71.4%). Conclusion: Detection rates on 18F-FCH PET/CT were superior to both 99mTc-sestamibi dual-phase scintigraphy with early SPECT/CT and neck ultrasonography in preoperative localization of parathyroid lesions in patients with primary hyperparathyroidism. [ABSTRACT FROM AUTHOR]

Introduction: The objective of this study was to compare 99mTc MIBI myocardial perfusion SPECT and Dobutamine Stress Echocardiography (DSE) in detecting viable myocardium in patients with Coronary Artery Disease. Materials and Methods: Total of 50 patients who with CAD and poor LV function were idenitifed on 2D Echo using 16 segment cardiac model. These patients underwent 99mTc MIBI myocardial perfusion SPECT and Dobutamine Stress Echocardiography and the results were compared with the gold standard 18F-FDG PET-CT findings. Results: A Total of 550 dysfunctional segments were identified in datasets of 50 patients on 2D echo. No significant difference was noted between the pairwise positive outcome of viable segment between MIBI SPECT and DSE (p=0.875). MIBI SPECT showed a sensitivity of 86.5% and specificity of 90.0% when compared with 18F-FDG PET-CT which was comparable with DSE having a sensitivity of 87.6% and specificity of 90.7%. Conclusion: 99mTc MIBI SPECT is an effective good alternative for evaluation of viable myocardial segments in patients with dysfunctional myocardium and can be considered especially in elderly or obese patients and patients with lung disease having poor echocardiographic imaging window due to lack of an optimal acoustic window. [ABSTRACT FROM AUTHOR]

Planar whole-body bone scanning (WBS) is widely used to evaluate skeletal lesions seen in cancer and noncancer cases. Frequently, degenerative, or other benign bony changes may give rise to indeterminate lesions that mimic bone metastases. In the post-COVID-19 era, there is an evolutionary phase that puts importance on global development and adaptability, which encompasses to include nuclear medicine practices worldwide. Single-photon emission computed tomography/computed tomography (SPECT/CT) can be used to improve the characterization of these lesions and help to resolve the diagnostic conundrum while reducing the need for patients to undergo multiple different examinations at various imaging departments. The fusion of SPECT and CT allows morphological characterization of functional abnormality detected by focal tracer uptake on planar scintigraphy, which provides a one-stop center imaging in nuclear medicine departments. The objective of this study was to review the diagnostic accuracy of SPECT/CT in diagnosing bone metastases in a variety of oncology and nononcology cases and to determine the feasibility of performing bone SPECT/CT in all suspected cancer cases, including cases of bone infection instead of planar imaging alone. The utilization of hybrid SPECT/CT in indeterminate bone lesions detected on planar WBS can significantly increase the diagnostic confidence and accuracy of image interpretation. Recognition of patterns of disease identified using hybrid imaging can improve the management of patients with potentially lower costs in the long term. Currently, hybrid SPECT/CT machines are becoming a norm in nuclear medicine departments, thus potentially making single planar application machines obsolete in the near future. We hypothesize that in the interest of providing a meaningful interpretation of isotope bone scans, the default protocol should involve the option of acquiring SPECT/CT images rather than relying on whole-body scans only. Departments choosing to upgrade existing equipment or those choosing to invest in only one gamma camera should proactively opt for hybrid SPECT/CT systems. [ABSTRACT FROM AUTHOR]

Seminomas are common germ cell tumors (GCT) that may arise in the testes as well as in extra testicular locations such as mediastinum with/without testicular tumor. Testicular tumors are usually detected early due to their location and presentation as testicular mass. The overall prognosis of the seminomatous GCTs is good with surgery as the mainstay of treatment in localized disease. Bone metastases, especially when present in isolation are exceedingly rare in seminoma. Here, we present a rare case of skull bone metastasis in a case of testicular seminoma which was detected on technetium-99m labeled methylene diphosphonate bone scintigraphy with single-photon emission computed tomography with computed tomography. [ABSTRACT FROM AUTHOR]

Purpose of the Study: The purpose of the study is to evaluate 99mTc-labeled ethambutol (99mTc-EMB) as a potential diagnostic agent in lymph node tuberculosis (LNTB). Materials and Methods: A prospective pilot study was done at All India Institute of Medical Sciences, New Delhi. We included adult consenting patients who were diagnosed with LNTB and were either treatment naïve or had just started treatment. Patients were injected with 10-15 mCi of 99mTc-EMB. Whole-body anteroposterior planar imaging was done from 15 min after injection at serial intervals till 4-6 h along with one single-photon emission computed tomography--computed tomography (SPECT-CT) imaging with the help of a dual-head SPECT-CT gamma camera. The uptake of 99mTc-EMB was analyzed and corroborated with clinicoradiological findings. Results: Between January 2019 and November 2020, we recruited 23 patients who underwent 99mTc-EMB, and 19 scans were interpretable and considered for analysis. Cervical lymphadenopathy was the most common presentation (13, 68.42%), followed by mediastinal (9, 47.36%) and abdominal (4, 21.05%) nodes. Other involvement included pulmonary (8, 42.1%), gastrointestinal (3, 15.78%), and chest wall abscess and bone marrow deposits in 1 patient each. A positive scan was noted in 7 (53.84%) patients with cervical lymphadenopathy, whereas uptake in abdominal and mediastinal lymph nodes was seen in 1 (25%) and 2 (22.22%) cases, respectively. Uptake in pulmonary lesions was noted in 3 (37.5%), but uptake in hepatic and splenic lesions was not seen. Conclusion: 99mTc-EMB scan can demonstrate drug penetrance in vivo in some patients with LNTB and should be explored further with a larger sample size. [ABSTRACT FROM AUTHOR]

We present a case of an 18-year-old male athlete who presented with complaints of right lower leg pain for 10 days following intense exercise. The most likely diagnosis was a possible tibial stress fracture or a "shin splint" syndrome. The radiograph did not reveal any significant abnormality in the form of any fracture or a cortical break. We performed planar bone scintigraphy including single-photon emission computed tomography (CT)/CT that revealed the presence of the two concomitant pathologies in the form of a hot spot which corresponded with a bone lesion in the tibial stress fracture and subtle remodeling activity without evidence of significant cortical lesion in the shin splints in bilateral lower limbs (R>L). [ABSTRACT FROM AUTHOR]

Background: The aim of this study was to determine the advantages of preoperative sentinel lymph node mapping (SLNM) by single photon emission computed tomography/computed tomography (SPECT / CT) in patients with early-stage cutaneous head-and-neck malignancies. Materials and Methods: We conduct a 7-year and 6 months retrospective, cross-sectional study. Patients with early-stage malignant head-and-neck skin tumors and cutaneous adnexa who underwent SLNM by SPECT/CT from March 2012 and December 2019, were included in the study. Results: We retrospectively analyzed 28 patients: Melanoma was the most frequent tumor (64.2%), followed by squamous cell carcinoma (25%). The anterior cheek was the most common functional subsite (25%). Twenty-seven patients (96.4%) had a successful SLN detection with SPECT/CT. Neck lymph node dissection was performed in 23 patients (82.1%). According to the pathological specimen, lymph nodes were found in all of them; hence, the efficacy of the SPECT/CT for SLNM was 100%. At 7-year follow-up, systemic recurrence was found in one patient (3.6%), another had locoregional recurrence (3.6%), and the mortality rate was 3.6%. Conclusions: In early-stage malignant head-and-neck skin tumors, there is a high concordance between SLN found by SPECT/CT and the histopathological results. Preoperative SPECT/CT accurately detects the SLN, assesses unexpected lymph nodes and their drainage pathways, and facilitates their location by reliably showing the relationships between sentinel nodes and important anatomic structures. This allows to perform a clear preoperative evaluation, an accurate staging for all patients and to avoid excessive dissections that could result in cosmetic and functional deformities. [ABSTRACT FROM AUTHOR]

Allogenic bone is the most commonly grafted tissue which provides only osteoconductive property, in which it acts as a scaffold to facilitate the ingrowth of the vessels and migration of host cells capable of osteogenesis. It can be used as a substitute for autografts as the latter is associated with morbidity and limited donor site availability. Its applications are expanding in all aspects of orthopedic surgery, notably in revision hip replacement or surgical treatment for bone tumors or benign conditions. The balance between osteolysis and osteogenesis must be maintained for graft incorporation to occur and thus postoperative imaging is essential for differentiation between grafts and recurrent disease or viability/nonviability. Here, we present three cases, in which bone allografting was done who underwent serial 99 mTc-methylene diphosphonate three-phase bone scintigraphy with single-photon emission computed tomography/computed tomography to assess the viability, integrity, and the incorporation of the graft. [ABSTRACT FROM AUTHOR]

Aim: To estimate the standard uptake values (SUVs) of Tc-99m methylene-diphosphonate (Tc-99m MDP) from normal skeletal sites in breast cancer patients using quantitative single-photon emission computed tomography (SPECT). Materials and Methods: A total of 60 breast cancer patients who underwent Tc-99m MDP SPECT/CT study at different postinjection acquisition times were included in this study. Based on postinjection acquisition time, patients were divided into four study groups (n_15 each), i.e. Ist (2 h), IInd (3 h), IIIrd (4 h), and IVth (5 h). Image quantification (SUVmax and SUVmean) was performed using Q.Metrix software. Delineation of volume of interest was shaped around different bones of the skeletal system. Results: The highest normal SUVmax and SUVmean values were observed in lumber and thoracic vertebra (8.89 ± 2.26 and 2.89 ± 0.58) for Group I and in pelvis and thoracic (9.6 ± 1.32 and 3.04 ± 0.64), (10.93 ± 3.91 and 3.65 ± 0.97), (11.33 ± 2.67 and 3.65 ± 0.22) for Group II, III and IV, respectively. Lowest normal SUVmax and SUVmean values were observed in humerus and ribs (3.22 ± 0.67 and 0.97 ± 0.18), (5.16 ± 1.82 and 1.18 ± 0.16) for Group I, IV, and in humerus (3.17 ± 0.58 and 0.85 ± 0.26), (3.98 ± 1.12 and 1.04 ± 0.28) for Group II and III, respectively. Significant difference (P < 0.05) noted in SUVmax for sternum, cervical, humerus, ribs, and pelvis with respect to time. However, significant difference (P < 0.05) noted in SUVmean for all skeletal sites with respect to time. Conclusions: Our study shows variability in normal SUV values for different skeletal sites in breast cancer patients. Vertebral bodies and pelvis contribute highest SUV values. Time dependency of SUVs emphasizes the usefulness of routinely acquired images at the same time after Tc-99m MDP injection, especially in follow-up studies. [ABSTRACT FROM AUTHOR]

In this case, we demonstrated a ureteric stone that resembled bone metastasis. Because bone-seeking radiopharmaceuticals are excreted into the urine by the kidneys, normal kidneys and bladder are well visualized on skeletal scintigraphs leading to incidental detection of urinary tract abnormalities. Bone tracer uptake related to ureteral stones has been reported [Figure 1] several times before. We present a right ureteral stone mimicking abnormal focal sacral uptake on planar scan in a patient with rectal cancer. This case emphasizes the importance of using single-photon emission computed tomography/computed tomography to determine the cause of abnormal uptake on a planar scan.{Figure 1} [ABSTRACT FROM AUTHOR]

Very few imaging techniques can demonstrate the presence of Mycobacterium tuberculosis in vivo. Technitium-99m Ethambutol scintigraphy is one of them, although literature on the utility of this technique is scarce. We describe a patient with iliopsoas abscess showing increased uptake on Tc-99 m ethambutol scintigraphy which was later confirmed to be tubercular by the microbiological analysis of pus. [ABSTRACT FROM AUTHOR]

We report a patient with multiple myeloma (MM) and polyarthritis of large joints. During the staging of the disease, bone marrow diffusely involved by MM was clearly demonstrated by 99mTc-2-methoxy-isobutyl-isonitrile (MIBI) single-photon emission computed tomography/computed tomography (SPECT/CT) but not by 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography/CT images. On the other hand, a very intense uptake of 18F-FDG was detected in periarticular tissues of multiple joints, with nonabnormal 99mTc-MIBI accumulation. Rheumatology tests were negative. A subsequent bone scintigraphy demonstrated radiolabeled bisphosphonate accumulation in periarticular tissues, suggesting amyloid arthropathy. [ABSTRACT FROM AUTHOR]

Neuroblastoma is the most common pediatric extracranial solid tumor. High-risk neuroblastoma is the most frequent presentation with an overall survival of approximately 50%. 123I-meta-iodobenzylguanidine (123I-mIBG) scintigraphy in the assessment of the primary tumor and its metastases at diagnosis and after chemotherapy is a cornerstone imaging modality. In particular, the bulk of skeletal metastatic disease evaluated with 123I-mIBG at diagnosis and the following chemotherapy has a prognostic value. Currently, single-photon emission computerized tomography/computerised tomography (SPECT/CT) is considered a fundamental part of 123I-mIBG scintigraphy. 123I-mIBG SPECT/CT is a highly specific and sensitive imaging biomarker and it has been the basis of all existing neuroblastoma trials requiring molecular imaging. The introduction of SPECT/CT has shown not only the heterogeneity of the mIBG uptake within the primary tumor but also the presence of completely mIBG nonavid metastatic lesions with mIBG-avid primary neuroblastomas. It is currently possible to semi-quantitatively assess tracer uptake with standardized uptake value, which allows a more precise evaluation of the tracer avidity and can help monitor chemotherapy response. The patchy mIBG uptake has consequences from a theranostic perspective and may partly explain the failure of some neuroblastomas to respond to 131I-mIBG molecular radiotherapy. Various positron emission tomography tracers, targeting different aspects of neuroblastoma cell biology, are being tested as possible alternatives to 123I-mIBG. [ABSTRACT FROM AUTHOR]

Vertebral tuberculosis (TB) is a common form of extrapulmonary TB. Here, the slow-growing Mycobacterium bacillus reaches the disc space through the hematogenous route and leads to various complications. Radiological imaging and histopathology have been the mainstay of diagnosis, but radionuclide imaging techniques using radiolabeled antitubercular drugs have rarely found space in the clinical domain. Here, we present a case of vertebral TB, where a technetium-labeled antitubercular drug, ethambutol, was synthesized and used for imaging the bacteria in vivo. Thus, we demonstrate a rarely used potentially specific agent for tuberculous-infection imaging, which can be produced in-house, and provides rapid results. [ABSTRACT FROM AUTHOR]

Following a moving hot spot in the projections of raw images and profound perfusion defects in myocardial perfusion single-photon emission computed tomography (SPECT) imaging of a patient, a hypothesis was postulated that the perfusion defects were artifactual, and the high activity concentration of the gallbladder may be a culprit for this phenomenon, owing to flawed event positioning function of the gamma camera due to a malfunctioning digital event processor electronics board. To depict the characteristics of this artifact, a point source containing an activity of 3 mCi of pertechnetate is placed on the scanning table with the detector facing the table (at a distance of 30 cm), and then, in other detector positions and 1-min static images are acquired accordingly. The ratio is calculated as follows: count of the artifactual focus: 1860, count of the index focus: 705,727, and artifactual-to-index focus ratio: 0.003. In testing the uniformity of gamma camera based on the National Electrical Manufacturers Association protocol, a nonuniform response was detected, seemingly, a smaller field of view (FOV) is reproduced in the main FOV causing nonuniformity more than the acceptable level. The smaller flood image lies in the upper right corner of the main flood image. In essence, the extremely bright gallbladder was the source of error, and its image was reproduced in the FOV, which was superimposed on the left ventricular myocardium in some of the projections and was propagated to SPECT images. [ABSTRACT FROM AUTHOR]

Postpartum methicillin-resistant Staphylococcus aureus (MRSA) infection occurs in patients with complicated vaginal delivery or cesarean section. The infection can manifest as mastitis, endometritis, and if untreated may lead to toxic shock syndrome. We report a case of postpartum MRSA osteomyelitis diagnosed by 99mtechnetium-methylene diphosphonate skeletal scintigraphy and single-photon emission computed tomography-computed tomography (CT) that was further confirmed by magnetic resonance imaging and CT-guided biopsy. This multimodal imaging approach helped reach the diagnosis and in further management of the patient [ABSTRACT FROM AUTHOR]

Purpose of the Study: To establish the most appropriate ordered subset expectation maximization (OSEM) parameters for image reconstruction in Tc-99m methoxyisobutylisonitrile (MIBI) myocardial perfusion SPECT (MPS) and comparison with corresponding filtered back projection (FBP)-reconstructed images. Methods: A total of 99 stress-rest MPS studies (47 normal and 52 abnormal) were retrospectively analyzed using 16 different combinations of iterations and subsets. Images were reconstructed both with and without postreconstruction Butterworth filter (cutoff frequency and order for stress: 0.4 and 10 and for rest: 0.52 and 5, respectively) for each combination. A total of 3168 images were evaluated qualitatively by two nuclear medicine physicians on a scoring scale of 1-4. Best visual quality image iteration-subset combination was determined for each patient both with and without Butterworth filter and was further compared with FBP-reconstructed image. The interobserver agreement was obtained using kappa statistics. Results: The best quality images were obtained using a combination of four iterations and six subsets for both with and without Butterworth filter. The value of kappa for interobserver agreement for OSEM images with Butterworth filter was 0.570 and for OSEM images without Butterworth filter was 0.857. On comparison, FBP images were better than OSEM-reconstructed images without Butterworth filter (P < 0.0001 calculated using Fisher's exact test) with substantial agreement (kappa = 0.628). However, OSEM-reconstructed images with Butterworth filter were better than FBP images and showed moderate agreement (kappa = 0.486). Conclusion: The most appropriate OSEM reconstruction parameter in Tc-99m MIBI MPS is 4-iteration and 6-subset combination. FBP-reconstructed images were better than the images reconstructed with OSEM without postreconstruction Butterworth filter. However, OSEM-reconstructed image with Butterworth filter was better than FBP images. [ABSTRACT FROM AUTHOR]

Purpose of the Study: Our study purpose was to compare the epicardial fat volume (EFV) in myocardial perfusion imaging single photon emission computed tomography/computed tomography (MPI SPECT/CT) with normal and abnormal perfusion in patients with known or suspected coronary artery disease (CAD). Materials and Methods: one hundred and seventy-six patients (88 records with normal and 88 with reversible perfusion defects) underwent physical or adenosine stress with Tc-99m MIBI followed by SPECT and low-dose CT for attenuation correction. Rest MPI was done in patients showing perfusion defects on stress imaging. Software-based quantification of EFV was done by manually delineating pericardial contours with epicardial fat threshold set between -30 HU and -190 HU. Results: Median EFV in scans with normal perfusion was found to be 74.46 ml (32.92-211.51), and with reversible ischemia was 92.94 ml (43.70-207.53) with a median-summed difference score (SDS) of 5.00 (1.0-27). In 15 scans with reversible perfusion defects associated with infarcts in other segments, median EFV was 101.71 ml (63.03-156.46) with mean - SDS of 7.50 (standard deviation = 6.20). Scans with reversible perfusion defects demonstrated an increased EFV (median - 92.94 ml) when compared to scans with a normal perfusion (median = 74.64 ml) (P < 0.001). Conclusion: Our results demonstrated an increased EFV in scans with presence of active reversible ischemia compared to that of normal perfusion on MPI (P < 0.001) suggesting potential role of cardiac SPECT/CT to evaluate EFV for risk stratification of suspected CAD. [ABSTRACT FROM AUTHOR]

We present a case of Anti-IgLON 5 encephalitis with Lewy body dementia. 18F fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) scan and 99 mTc-TRODAT-1 SPECT/CT scan were done. 99 mTc-TRODAT-1 scan findings revealed severely reduced concentration of dopamine transporter in bilateral basal ganglia, suggestive of a degenerative parkinsonian disorder. 18F-FDG PET scan findings were suggestive of moderate-to-severe hypometabolism in the bilateral parieto-temporal and bilateral occipital cortices including the primary visual cortices, supporting Lewy body spectrum disease with associated hypermetabolism in the bilateral sensorimotor cortices, bilateral basal ganglia, thalami, brain stem, and bilateral cerebellar hemispheres suggestive of inflammatory pathology. [ABSTRACT FROM AUTHOR]

Background: Traumatic brain injury (TBI) is a critical health problem with various comorbidities and socioeconomic consequences. Tending to increase in recent decades, TBI results in more cases of consciousness disorders including vegetative state (VS)/minimally conscious state (MCS). However, no definite or effective treatment still exists for these conditions. The aim of this article is to study the effects of zolpidem in patients with VS caused by TBI by using brain perfusion single-photon emission computed tomography (SPECT). Materials and Methods: This was a prospective clinical trial on a cohort of patients with VS. We evaluated the TBI database to find VS/MCS patients, between the ages of 20 and 65 years. We received written consent from their family members prior to enrollment and compared their clinical status and brain perfusion SPECT prior and after 2 weeks of zolpidem therapy. Results: Among the 12 patients included in this study, six patients changed to MCS after 2 weeks. Comparison of their motor score, revealed a statistically significant difference (2.08 vs. 3.75, P = 0.007, respectively). None of the quantitative or qualitative brain perfusion parameters showed any differences after zolpidem therapy. However, the perfusion pattern, with focal or multifocal cortical defects, was significantly more prevalent in the responder group (five patients vs. one patient, P = 0.015). Conclusion: Zolpidem therapy may improve consciousness levels and motor function in a considerable portion of VS patients with TBI. This study showed that the presence of focal brain perfusion defect can predict response to zolpidem. [ABSTRACT FROM AUTHOR]

Purpose: In single-photon emission computed tomography imaging, the presence of scatter degrades image quality. The goal of this study is to optimize the main-?and sub-energy windows for triple-energy window (TEW) method using Monte Carlo SImulating Medical Imaging Nuclear Detectors (SIMIND) code for samarium-153 (Sm-153) imaging. Materials and Methods: The comparison is based on the Monte Carlo simulation data with the results estimated using TEW method. Siemens Symbia gamma-camera equipped with low-energy high-resolution collimator was simulated for Sm-153 point source located in seven positions in water cylindrical phantom. Three different main-energy window widths (10%, 15%, and 20%) and three different sub-energy window widths (2, 4, and 6 keV) were evaluated. We compared the true scatter fraction determined by SIMIND and scatter fraction estimated using TEW scatter correction method at each position. In order to evaluate the image quality, we used the full width at half maximum (FWHM) computed on the PSF and image contrast using Jaszczak phantom. Results: The scatter fraction using TEW method is similar to the true scatter fraction for 20% of the main-energy window and 6 keV sub-energy windows. For these windows, the results show that the resolution and contrast were improved. Conclusion: TEW method could be a useful scatter correction method to remove the scatter event in the image for Sm-153 imaging. [ABSTRACT FROM AUTHOR]

Many surgical procedures may injure lymphatic channels unexpectedly, such as lymph node dissections, transplantations, and vessel reconstructions, and will lead to iatrogenic lymphatic leakage. We hereby present a case of postoperative lymphocele diagnosed more precisely by single-photon emission computed tomography (SPECT)/CT fusion imaging. [ABSTRACT FROM AUTHOR]

Gated imaging, as a technically demanding procedure, requires special attention and effort to fulfill the technical adequacy and accuracy of the study, based on the available standard guidelines. One of the essential requirements to be met by both technologists and physicians, in nuclear cardiology, is triggering and synchronization as a fundamental subject of gating. There are many sources of gating errors that produce imaging artifacts and, in some occasions, render the images uninterpretable or the quantitative analyses less accurate. Sufficient knowledge of recognition of these artifacts and understanding of their related mechanisms (from physical and technical perspectives) enable the technologists and physicians to promote their performance in daily practice. In this article, intended as a readily practical technical review for nuclear medicine practitioners, it is aimed to present the technical and computer aspects of triggering and synchronization as well as the related errors during imaging. [ABSTRACT FROM AUTHOR]

Myocardial perfusion single-photon emission computed tomography (SPECT) as a common imaging procedure in nuclear medicine laboratories may encompass findings in the heart or beyond it, in the thorax or abdomen, which may be related or unrelated to the symptoms of the patients. Sometimes, these findings may be discovered incidentally. In the present article, it is aimed to present some less frequent cardiac and extracardiac findings including radiolabeled emboli, transposition of great arteries, breast prosthesis, breast tissue uptake, pericardial effusion, hiatal hernia, hepatocellular carcinoma, ascites, aortic aneurysm, splenomegaly, and polycystic kidney disease during 99mTc-methoxyisobutylisonitrile myocardial perfusion SPECT with their radiological correlates. [ABSTRACT FROM AUTHOR]

Background: Coronary artery calcification (CAC) can be visually estimated on computed tomography (CT) attenuation correction (CTAC) of positron emission tomography (PET). The visual estimation of CAC from CTAC scans performed for PET/CT is comparable to the standard CAC score scan. Myocardial perfusion imaging (MPI) with single-photon emission CT (SPECT) is commonly performed for risk stratification before oncologic surgery. Objective: We investigated the value of visual estimation of CAC from CTAC of PET/CT as well as other factors such as coronary artery disease (CAD) risk factors and type of cancer as predictors of MPI ischemia. Methods: Retrospectively, we identified 268 patients who underwent PET/CT and MPI for preoperative cardiac evaluation. Visual estimation of CAC was performed and classified into four categories. Results: The results of visual CAC were as follows: 47.8% - zero CAC, 32.8% - mild CAC, 14.2% - moderate CAC, and 5.2% - severe CAC. The majority of patients (85.8%) had normal MPI, whereas 14.2% were abnormal. There was a strong association between ischemia on MPI and CAC seen on CTAC (P < 0.01), dyslipidemia (P < 0.01), family history of CAD (P < 0.05), smoking (P < 0.01), and type of malignancy (P < 0.01). Conclusion: A strong association exists between visual estimation of CAC on CTAC and MPI. Zero is highly associated with normal MPI, but moderate-to-severe CAC is associated with abnormal MPI, in addition smoking, dyslipidemia, and certain cancer are associated with ischemic MPI; subsequently, preoperative cardiac testing is warranted in these subsets of patients. [ABSTRACT FROM AUTHOR]

Introduction: In lutetium-177 (Lu-177) single-photon emission computed tomography (SPECT) imaging, the accuracy of activity quantification is degraded by penetrated and scattered photons. We assessed the scattered photon fractions in order to determine the optimal situation and development of correction method. This study proposes to compare the image quality that can be achieved by three collimators. Materials and Methods: Siemens Medical System Symbia fitted with high-energy (HE), medium-energy (ME), and low-energy high-resolution collimators was simulated using the SIMIND Monte Carlo code simulation code. Counts were collected in three different main-energy window widths (20%, 15%, and 10%) for Lu-177 point source. Primary and scattered point spread functions and also geometric, penetration, scattering were drawn and analyzed. Results: In Lu-177 imaging, a 20% of main-energy window and ME collimator were found to be optimal. HE collimator can be used when the resolution is not required. Conclusion: These results provide the optimal energy window and collimator in Lu-177 SPECT imaging and will help the quantification of Lu-177. [ABSTRACT FROM AUTHOR]

Coronary artery disease (CAD) is the leading cause of morbidity and mortality worldwide. Invasive coronary angiography (ICA) is the gold standard for the evaluation of epicardial CAD. In the pathogenesis of the CAD, myocardial perfusion abnormalities are the first changes that appear followed by wall motion abnormalities, electrocardiogram changes, and angina. Myocardial perfusion imaging (MPI) demonstrates the cumulative effect of pathology at epicardial coronary arteries, small vessels, and endothelium. Thus, it evaluates the overall burden of ischemic heart disease (IHD). MPI is used noninvasively to diagnose early asymptomatic CAD or to know the functional significance of known CAD. There are evidence that early detection of myocardial perfusion abnormalities followed by aggressive intervention against cardiovascular risk factors may restore myocardial perfusion. This may lead to reduce morbidity and mortality. Various MPI modalities have been used to diagnose and define the severity of CAD. Cardiac myocardial perfusion single-photon emission computed tomography (myocardial perfusion scintigraphy [MPS]) has been in use since decades. Several newer modalities such as positron emission tomography, cardiac magnetic resonance imaging, computed tomography perfusion, and myocardial contrast echocardiography are developing utilizing the similar principle of MPS. We shall be reviewing briefly these modalities, their performance, comparison to each other, and with ICA. [ABSTRACT FROM AUTHOR]

A 45-year-old male with a history of trauma was referred to the department of nuclear medicine to identify site of a biliary leak, which could not be identified in ultrasound and exploratory laparotomy. Contrast-enhanced computed tomography (CT) was able to identify lacerations in the right lobe of the liver, but the extent of injury to the biliary pathways and vessels was unclear. 99mTc-HIDA scintigraphy with single-photon emission CT/CT was not only able to identify the site of leak but also the extent of infarcted area. [ABSTRACT FROM AUTHOR]

A 7-year-old male with a history of blunt trauma to the abdomen and diagnosis of perinephric hematoma in contrast-enhanced computed tomography (CT) presented with increasing peri-nephric collection (after ~1.5 months) in the serial ultrasound examinations. The patient was referred to the department of nuclear medicine for the assessment of this collection as well as renal function. In 99mTc-diethylenetriamine pentaacetate renal scintigraphy, progressively increasing radiotracer activity was noted inferolaterally to the left kidney, separated from the same by a photopenic area. Single-photon emission computed tomography/CT revealed a peri-nephric urinoma in relation to the previously diagnosed hematoma at the lower pole; which was communicating with the pelvi-calyceal system (PCS). Not only did the renal scintigraphy aid in the diagnosis of urinoma but it was also able to show that it was communicating freely with the PCS and that the rest of the renal parenchyma was functioning adequately. This multi-faceted assessment in a single investigation allowed clinicians to opt for the conservative management despite the increasing size of urinoma in the early follow-up. [ABSTRACT FROM AUTHOR]

Introduction: The choice of the radionuclide has a key role in nuclear medicine which appearing the lowest scatter fraction. In addition, the presence of penetrated and scattered photons from collimator in single-photon emission computed tomography images degrades resolution and contrast. Thus, image quality depends on sensitivity and resolution of the collimator-detector system. The goal of this study was to compare the image quality that can be achieved by three radionuclides: technetium-99 m (Tc-99 m), iodine-123 (I-123), and samarium-153 (Sm-153). Materials and Methods: Tc-99 m and Sm-153 were imaged with low-energy high resolution (LEHR) collimator, while I-123 was imaged with medium-energy (ME) collimator. We modeled the Siemens Symbia Medical system using Monte Carlo simulation code SIMIND. The imaging characteristics of each radionuclide were investigated by simulated data: point spread function, sensitivity (Cps/MBq) and geometric, penetration and scattering distribution. Results: Tc-99 m and Sm-153 give best and results with LEHR collimator for spatial resolution (full width at half maximum [FWHM] = 3.19 mm; full width at tenth maximum [FWTM] = 6.73 mm) and (FWHM = 3.22 mm; FWTM = 7.39 mm), respectively. Whereas, I-123 provided with ME collimator a lower resolution (FWHM = 4.89 mm; FWTM = 9.89 mm). The sensitivity recorded by Tc-99 m, Sm-153, and I-153 were (31.21 Cps/MBq), (10.16 Cps/MBq), and (51.22 Cps/MBq), respectively. Conclusion: Tc-99 m and Sm-153 give the best and generally similar imaging properties with LEHR. For I-123, the ME collimator helps lowering the influence of high-energy gamma rays. [ABSTRACT FROM AUTHOR]

Fibrodysplasia ossificans progressiva is a rare genetic disease believed to occur in approximately 1 in 2 million people worldwide and is characterized by progressive extraosseous ossification over the course of a lifetime in an inevitable and unpredictable episodic manner, with most patients being confined to a wheelchair by the third decade of life and requiring life-long care. The extraosseous calcification involves ligaments, tendons, muscles, and connective tissue leading to severe restriction of movements. Another hallmark of this condition is abnormal great toes. The diagnosis is often made on clinical and radiological examination, but Technetium-99m methylene diphosphonate (Tc-99m MDP) bone scan is usually indicated to determine the extent of the disease. We hereby present a case series comprising of four patients suffering from this debilitating illness who underwent Tc99m MDP bone scan for initial diagnosis and localizing sites of heterotopic ossification. [ABSTRACT FROM AUTHOR]

Background: The association between myocardial ischemia in high-risk patients with coronary calcium score (CCS) and high-sensitivity C-reactive protein (hs-CRP) is not well established. Aims: We evaluated the correlation between hs-CRP, CCS, and myocardial ischemia in asymptomatic high-risk patients without known coronary artery disease (CAD). Materials and Methods: We prospectively assessed 68 asymptomatic high-risk outpatients without known CAD. One-day rest-stress Tc-99m single-photon emission computed tomography (SPECT) myocardial perfusion imaging and multislice computed tomography were performed. Multivariate regression analysis was performed for the assessment of predictors of myocardial ischemia. Standard risk factors and hs-CRP values were analyzed. Results: CCS >0 Agatston score was observed in 26 patients (46.4%). Seven patients had CCS between 10 and 99 AU, 8 patients between 100 and 400 AU, and 11 patients had CCS >400 AU. Mild ischemia was noted in 11 patients, moderate ischemia in 10 patients, and severe ischemia in 6 patients. Hs-CRP was >1 mg/L in 39 patients, of whom 8 patients had CCS >0, 13 patients had normal SPECT results, 6 patients had mild ischemia, and 12 patients had moderate and severe ischemia. Multivariate regression analysis showed independent predictors for increased CCS: low-density lipoprotein cholesterol (odds ratio [OR]: 2.891; P = 0.001); age >70 years (OR: 2.568; P = 0.001); and smoking (OR: 1.931; P = 0.001). We found hs-CRP to be an independent predictor of myocardial ischemia (OR: 4.145; 95% confidence interval: 1.398–7.471, P = 0.001). Conclusion: hs-CRP was an independent predictor of myocardial ischemia. hs-CRP might improve the selection of high-risk asymptomatic patients for myocardial SPECT imaging. [ABSTRACT FROM AUTHOR]

Purpose: In yttrium-90 (Y-90) single-photon emission computed tomography (SPECT) imaging, the choice of the acquisition energy window is not trivial, due to the continuous and broad energy distribution of the bremsstrahlung photons. In this work, we investigate the effects of the energy windows on the image contrast to noise ratio (CNR), in order to select the optimal energy window for Y-90 imaging. Materials and Methods: We used the Monte Carlo SIMIND code to simulate the Jaszczak phantom which consists of the six hot spheres filled with Y-90 and ranging from 9.5 to 31.8 mm in diameter. Siemens Symbia gamma camera fitted with a high-energy collimator was simulated. To evaluate the effect of the energy windows on the image contrast, five narrow and large energy windows were assessed. Results: The optimal energy window obtained for Y-90 bremsstrahlung SPECT imaging was 120–150 keV. Furthermore, the results obtained for CNR indicate that the high detection is only for the three large spheres. Conclusion: The optimization of energy window in Y-90 bremsstrahlung has the potential to improve the image quality. [ABSTRACT FROM AUTHOR]

Cherubism, a rare hereditary fibro-osseous lesion characterized by painless expansion of jaws, starts early in life manifesting itself fully in the second decade of life and is almost regressed in the third decade. Here, we report a sporadic case of Cherubism with clinico-radiological and scintigraphic presentation of its classical features for its disease rarity and single-photon emission computed tomography/computed tomography findings with review the literature. [ABSTRACT FROM AUTHOR]

Here, we report a case of a 54-year-old woman affected by thyrotoxicosis, with scintigraphic evidence of a diffuse hyperfunctioning goiter and a large ectopic thyroid tissue in the thyroglossal duct remnant. The latter was apparently more active than the two lobes at 99mTc-pertechnetate scintigraphy, mimicking a condition of preexisting increased sensitivity to thyroid-stimulating hormone stimulation. On the other hand, single-photon emission computed tomography/computed tomography has proven to be a very useful tool in demonstrating this activity to be similar to the thyroid lobes and in defining extension and anatomical relationships of the mass. [ABSTRACT FROM AUTHOR]

Detection of recurrence of a brain tumor after treatment is one of the most important and challenging diagnostic problems in neuro-oncological practice. In spite of technical advances in imaging modalities, sometimes, certain clinical presentations and manifestations can lead to a diagnostic dilemma even with the best of the technical know-how. We present a case of recurrence of anaplastic oligoastrocytoma (World Health Organization Grade III), where the patient's initial clinical presentation and the F-18 flourodeoxyglucose positron emission tomography (PET) magnetic resonance imaging findings were suggestive of stroke-like migraine attacks after radiation therapy syndrome. Due to a seizure episode before PET image acquisition, intense gyral uptake was noted in the left parietal lobe which made it difficult to ascertain the presence of a tumor recurrence. However, Tc-99m glucohepatonate single-photon emission computed tomography done after 1 week revealed radiotracer uptake within the site corresponding to the primary tumor, and a diagnosis of recurrence was made. [ABSTRACT FROM AUTHOR]

A 9-year-old male patient, with an ultrasonography diagnosis of horseshoe kidney condition, was referred to our hospital for recurrent urinary tract infection. He was submitted to 99mTc-diethylenetriamine pentaacetic acid sequential scintigraphy that demonstrated urine stasis in the calyces of both kidneys and was also suggestive for 8-shaped right-to-left crossed-fused renal ectopia. A subsequently performed 99mTc-dimercaptosuccinic acid scan confirmed the diagnosis of crossed renal ectopia, also disclosing, through single-photon emission computed tomography (SPECT) acquisition, cortical uptake defects in both kidneys, and indicative of renal scarring due to recurrent pyelonephritis. Combined scintigraphy and appropriate technological approaches (SPECT/3D volume rendering) may be useful in selected patients with congenital anomalies. [ABSTRACT FROM AUTHOR]

A 13-year-old adolescent male presented with an episode of rectal bleed. He has had five such episodes in the past year where he witnessed black tarry stools mixed with fresh blood, painless, not associated with fever or hematemesis. Clinical examination revealed pallor and a soft, non-tender abdomen. Vitals were stable. Blood investigations revealed haemoglobin of 102g/L, WBC count of 10 X 109/L and platelet count of 165 x 109/L. The clotting screen was normal. Upper GI endoscopy and colonoscopy revealed no abnormality. The patient underwent Tc-99m pertechnetate scintigraphy to look for Meckel's Diverticulum in view of painless lower GI bleed. [ABSTRACT FROM AUTHOR]

Ebstein's anomaly is a rare congenital heart disease. We present the case of a 47-year-old woman with history of Ebstein's anomaly who was referred to nuclear medicine department for a myocardial perfusion single-photon emission computed tomography (SPECT) imaging during pre-anesthetic check-up. Myocardial SPECT perfusion images with (99mTc)-Sestamibi demonstrated medium sizes fixed perfusion defect in the mid and proximal infero-septal wall adjacent inferior wall. This is a cause of potential misinterpretation on myocardial SPECT perfusion imaging as this perfusion defect was due to fibrosis rather than scarred myocardium. [ABSTRACT FROM AUTHOR]

The dissemination and autotransplantation of viable splenic tissue in different anatomic compartments of the body can present a diagnostic dilemma, especially when metastatic disease is suspected. We report a case of a 30-year-old male with well-differentiated gastric neuroendocrine tumor (Grade II) treated with surgery. Follow-up 68Ga-DOTA-NOC demonstrated a suspicious peritoneal soft-tissue nodule in the right paracolic gutter with increased tracer uptake. In view of splenectomy 10 years ago, the patient underwent 99mTc heat-denatured erythrocyte study which showed a very unusual pattern of multiple tracer-avid foci of splenic tissue in both intraperitoneal and extraperitoneal distributions. The integration of the patient's history and complementary nuclear imaging results led to the correct diagnosis of splenosis. [ABSTRACT FROM AUTHOR]

Somatostatin receptor-targeted alpha radionuclide therapies have been introduced including actinium-225 labeled tetraazacyclododecanetetraacetic acid-octreotide (Ac-225 DOTATATE) for advanced metastatic neuroendocrine tumors (NET). Very limited data are available on the posttherapy imaging using Ac-225 DOTATATE therapy in metastatic NET. We present Ac-225 single-photon emission computed tomography/computed tomography images of a 72-year-old patient diagnosed as a case of advanced rectal NET treated primarily with Ac-225 DOTATATE. [ABSTRACT FROM AUTHOR]

Situs ambiguous or heterotaxy syndrome is defined as the abnormal arrangement of organs and vessels within the body. Herein, we present an 8-year-old girl with growing right-sided suprarenal masses mimicking adrenal tumors. Technetium-99-m-radiolabeled red blood cells' planar images were inconclusive for the diagnosis of splenic tissue in the right side. Single-photon emission computed tomography/computed tomography imaging clearly identified right-sided functioning spleens and confirmed the diagnosis of situs ambiguous with polysplenia. [ABSTRACT FROM AUTHOR]

99mTc diethylenetriaminepentaacetic acid (DTPA) renogram is a commonly performed evaluation postrenal transplant to assess graft function and for early detection of suspected immediate and late transplant-associated complications. Although several modalities can be utilized to detect perinephric collection in posttransplant period, the utility of 99mTc DTPA single-photon emission-computed tomography (SPECT-CT) is not recognized. Herein, we discuss the incremental role of seldom considered SPECT-CT in early detection, leading to timely appropriate management and graft salvage in a case of posttransplant deteriorating renal allograft as a result of subcapsular hematoma. [ABSTRACT FROM AUTHOR]

We report a 47-year-old woman who developed an ischemic stroke with diplopia and dysarthria. Emergency computed tomography (CT) showed no pathological findings, and magnetic resonance (MR) showed mild ischemic-degenerative lesions. MR angiography and angiogram showed severe stenosis of both internal carotid and main intracranial arteries with plenty collateral vessels with "puff of smoke" suggesting a moyamoya disease (MMD). Brain perfusion single-photon emission CT showed global diminished perfusion in the brain lobes and a marked relative hyperperfusion in the cerebellum. However, brain 18F-fluorodeoxyglucose-positron emission tomography showed physiological metabolism in the brain cortex with only slightly relative cerebellar hypermetabolism. MMD is a well-known arterial pathology that frequently develops with only mild symptoms until the middle age. Functional neuroimaging findings indicate a mismatch between brain glucose metabolism and brain perfusion, probably due to neuronal subclinical chronic ischemia in the brain cortex with preserved viability of neurons. [ABSTRACT FROM AUTHOR]