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Skeletal scintigraphy is one of the most widely performed investigations in any nuclear medicine department. However, there has been a paradigm shift in the indications for which bone scan was performed in the past 3 decades, mainly due to advancement in other imaging modalities, better disease understanding, and the development of newer disease-specific guidelines. The metastatic indications for bone scans accounted for 60.3% of cases in 1998 which reduced to 15.5% in 2021 and nonmetastatic indications rose from 39.7% in 1998 to 84.5% in 2021. Fewer bone scans are being performed for the metastatic survey, and more scans are being performed for nononcological orthopedic and rheumatological indications. This article captures the journey of skeletal scintigraphy in the past three decades.
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Objective: Low back pain (LBP) is a major cause of pain and disability. Identification of the pathology accurately or the pain generators is sometimes difficult with the conventional modalities such as magnetic resonance imaging (MRI), computed tomography (CT), or X-ray. Nuclear medicine investigations such as single-photon emission CT (SPECT/CT) or 18-fluorodeoxyglucose positron emission tomography-CT (18-FDG PET-CT) have emerged as an adjuvant tool in these cases. In this study, we evaluated and analyzed the role of 18-FDG PET-CT in identifying active pain generators and the outcomes of interventions based on that compared to MRI. Methodology: This study included all patients who fell under inclusion criteria presented with chronic LBP with or without radiculopathy. History and clinical examination were done as well as Visual Analog Scale (VAS) and Oswestry Disability Index (ODI) scores were calculated. All the patients underwent MRI lumbosacral spine with sacroiliac (SI) joint and 18-FDG PET-CT whole spine. Patients in whom PET-CT was positive and active pain generator was identified were managed for the specific level or pain generator responsible by appropriate modalities, i.e. surgery, interfacetal injections, transforaminal epidural injections, and SI joint injections. Patients in whom PET-CT was negative were managed according to the pain generator identified on the basis of MRI and clinical correlation. Patients were told to follow-up after 1 week and 1 month, and subsequent improvement was evaluated on the basis of VAS after 1 week and 1 month and ODI score after 1 month. Results: A total of 20 patients were included in the study, with a mean age of 41.9 ± 13.53 years. Twelve patients had multiple level pathology without the indication of significant pain generator and eight patients' symptoms did not correlate with the MRI findings. 18-FDG PET-CT was done in all patients. 10% (2/20) patients were identified with active pain generators on PET-CT which were not identified on MRI. Eleven out of twenty patients underwent intervention in the form of surgery or pain injections. The mean VAS and ODI score in the patients intervened on the basis of 18-FDG PET-CT improved by 70.59% and 50%, respectively, whereas in patients who underwent intervention on the basis of MRI had improvement in mean VAS and ODI score by 58.57% and 30.81%, respectively after 1 month. Conclusion: Inflammation and associated degenerative process in the spine is a continuous process and affects multiple levels and might not be easily picked up on MRI or other conventional modalities. Thus, 18-FDG PET-CT is useful in identifying these active inflammatory processes and thereby helping in the localization of active pain generators. Treating these active pain generators has a better outcome in patients after intervention in terms of better pain relief and quality of life and also reduces the levels being treated.
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Myocardial perfusion imaging (MPI) is an important investigative tool in the diagnosis and management of coronary artery disease. This investigation has seen a manifold increase in number in past decades as compared to other investigations such as cardiac magnetic resonance imaging/positron emission tomography or computed tomography. In 2005, "Appropriate use criteria (AUC) in cardiac radionuclide imaging" was formulated by the American College of Cardiology Foundation and the American Society of Nuclear Cardiology for effective use of this investigation, later revised in 2009. We assessed the appropriateness of indications for MPI in patients presenting to the nuclear medicine department of a tertiary care hospital according to the latest AUC for cardiac radionuclide imaging. This is a retrospective analysis of all cardiac perfusion scans performed from June 2019 to January 2020 in a tertiary care teaching hospital in South India. All patients' indications for MPI were assessed for appropriateness using AUC 2009 as appropriate, inappropriate, and uncertain indications by two experienced nuclear medicine physicians blinded for results of the test and hospital stay of the patients. A total of 1015 cardiac scans were performed in the given period, which were analyzed. This included 613 males and 402 females, with most of the patients aged above 60 years (n = 640; males = 385, females = 255). Most of the patients had diabetes mellitus or hypertension or both except in 161 patients (15.8%) which did not have either of the comorbidities. Chest pain and/or shortness of breath were the most common presenting complaints. The appropriate indication for imaging was found in 784 patients (77.2%), inappropriate in 121 patients (12%), and uncertain in 110 patients (10.8%). Our results showed appropriate indication to be 77.2% and inappropriate indications as 12% for MPI referrals in a tertiary care teaching hospital, similar to Western literature but can be improved further by continued teaching and awareness campaigns.
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Insufficiency fractures (IFs) can be challenging to diagnose due to varied presentations, and sometimes, it changes the course of treatment, as in cancer patients in whom it has to be differentiated with metastatic disease. We present the role of Technetium 99m methylene diphosphonate (99mTc-MDP) bone scan, which is a low-cost, simple to perform, whole body diagnostic investigation in the diagnosis of IFs. This is a retrospective analysis of all patients who underwent a 99mTc-MDP bone scan in a tertiary care teaching hospital during 2013-2017 and were diagnosed as having an IF on bone scan. The bone scans were performed on a dual-head gamma camera using low-energy high-resolution collimators. Of all the bone scan performed during 2013-2017, a total of 138 patients with a mean age of 57.5 ± 14.7 years were diagnosed as having IFs based on bone scan and final clinical diagnosis. Among them, the most common complaint was regional bony pain in 62% of patients, while the most common cause was osteoporosis in 47% of patients, both postmenopausal and senile osteoporosis. In all, 265 sites of fractures were identified with a fracture average of 1.9/patient, the most common site being dorsolumbar vertebrae, followed by ribs and lower limb bones. Many unusual sites were also identified such as talus, sternum, clavicle, and scapula. 99mTc-MDP bone scan, being noninvasive whole-body imaging, is a useful investigation for evaluation of IFs and in correlation with biochemical analysis and other imaging can be used to determine the etiology of IF.
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Pelvic insufficiency fractures (IFs) are frequently diagnosed on technetium-99m methylene diphosphonate bone scan (BS), where it remains an important diagnostic imaging modality. Involvement of iliac bone in pelvic IFs is very rare. Differentiation from metastases is crucial where BS shows characteristic appearance obviating the need for further investigations for confirmation. There are many diagnostic appearances reported on BS for the diagnosis of IFs at various sites. We present a patient with cervical carcinoma who was previously treated with external beam radiotherapy to pelvis and now presented with pelvic pain. BS was performed to rule out skeletal metastases, however, the findings were diagnostic for iliac IF.
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BACKGROUND: Accumulated evidence indicates that exposure to trauma is associated with the development of cognitive impairments and psychiatric symptoms in children and adolescents. OBJECTIVE: In this case study of a female adolescent of 17 years, we aimed to evaluate how cortical positron emission tomography (PET) abnormalities relate to psychogenic non-epileptic seizure (PNES) dissociative state, post-traumatic stress disorder (PTSD), attention-deficit/hyperactivity disorder (ADHD), and domestic violence exposure. METHODS: Detailed psychiatric and neuropsychological assessment was performed initially, followed by a PET study. The PET imaging was carried out in the resting-state and in the dissociative-state. RESULTS: The adolescent was suffering from multiple episodes of unconsciousness, all found to be psychogenic; thus, PNES was diagnosed. However, at the psychopathology symptom level, the adolescent had heightened impulsivity, hyperactivity, hyperarousal, anxiety, somatic, and dissociative/ functional neurological symptoms present separately or concurrently at some point during her life; thus, the criteria for PTSD and ADHD were also fulfilled. In the resting state, significant hypometabolism was observed in the occipital, occipitotemporal, polar, and mesial parts of the temporal regions bilaterally, fronto-parietal medial and lateral pericental regions, and fronto-temporal and insular region on the left. The most intense metabolism was observed in the posterior cingulate gyrus and the medial parts of the posterior parietal lobe. In the dissociative state, there was a slight increase in the metabolism of the brain globally compared with the resting state, but with identical distribution of the regional changes observed. CONCLUSIONS: Widespread cortical PET abnormalities were found, possibly indicating alterations in large-scale brain networks, in a patient with PNES and a dissociative state, PTSD, and ADHD, who was exposed to chronic domestic violence.
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Renal masses account for 55% of cases presenting as palpable abdominal mass in children.[1] An eight year male presented with palpable abdominal mass and pain. The patient underwent renal dynamic scan, which raised possibility of left duplex kidney with non-functioning moiety, as the size of left kidney was smaller than seen on Ultrasonography (USG). Magnetic resonance (MR)urography confirmed the findings with patient undergoing left hemi-nephrectomy and is doing well. In case of discrepancy in size of kidney on USG and renal scan, duplex kidney should be considered as differential, other causes being, renal cyst, benign/malignant mass and renal calculi. Gross hydro-ureter presenting as palpable abdominal mass is very rare with few reported cases.[234].
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BACKGROUND: To evaluate the advantages of contrast enhanced F-18-fluorodeoxyglucose (FDG) positron emission tomography-computed tomography (PET-contrast enhanced CT [CECT]) when used as an initial imaging modality in patients presenting with metastatic malignancy of undefined primary origin (MUO). MATERIALS AND METHODS: A total of 243 patients with fine needle aspiration cytology/biopsy proven MUO were included in this prospective study. Patients who were thoroughly evaluated for primary or primary tumor was detected by any other investigation were excluded from the analysis. Totally, 163 patients with pathological diagnosis of malignancy but no apparent sites of the primary tumor were finally selected for analysis. The site of probable primary malignancy suggested by PET-CECT was confirmed by biopsy/follow-up. RESULTS: PET-CECT suggested probable site of primary in 128/163 (78.52%) patients. In 30/35 remaining patients, primary tumor was not detected even after extensive work-up. In 5 patients, where PET-CECT was negative, primary was found on further extensive investigations or follow-up. The sensitivity, specificity, positive predictive value and negative predictive value of the study were 95.76%, 66.67%, 88.28% and 85.71% respectively. CONCLUSIONS: F-18 FDG PET-CECT aptly serves the purpose of initial imaging modality owing to high sensitivity, negative and positive predictive value. PET-CECT not only surveys the whole body for the primary malignancy but also stages the disease accurately. Use of contrast improves the diagnostic utility of modality as well as help in staging of the primary tumor. Although benefits of using PET-CECT as initial diagnostic modality are obvious from this study, there is a need for a larger study comparing conventional methods for diagnosing primary in patients with MUO versus PET-CECT.
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Osteo-cutaneous flap are commonly used for reconstruction of bone defect after oncology surgery. The success of surgery depends on the viability of the bone flap. Bone scan is a known, but less performed method, to look for viability of bone flaps. We describe a case of 50-year-old lady, presenting with squamous cell carcinoma of left buccal mucosa (cT4N1M0) involving the skin and mandible. She underwent left segmental mandibulectomy and upper alveolectomy with neck dissection, followed by reconstruction using a fibular osteo-cutaneous flap and anterolateral thigh free flap. On postoperative day 10, the intraoral flap showed signs of nonviability. The patient was sent to nuclear medicine for assessment of viability of the free fibula flap. The patient underwent three phase (99m)Tc-methylene diphosphonate (MDP) bone scan and single-photon emission computerized tomography. Computerized tomography showing good tracer uptake in fibula confirming viability. The case reflects the use of (99m)Tc-MDP in viability assessment of the bone flap.
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When it comes to cancer, one can expect the unexpected. The clinical presentations can be very bizarre. One of these uncommon presentations is monoarticular arthritis. The age group affected by cancer and arthritis are similar. However, the possibility of joint pain being secondary to metastatic involvement does not come to mind easily. In this report, a 65-year-old postmenopausal woman presented with complaint of pain and restricted movement of the right knee joint, in whom the clinical and magnetic resonance imaging features were suggestive of infective monoarthritis. However, synovial fluid aspirate showed presence of malignant cells. Hence, patient was evaluated with whole-body (18)F-fluorodeoxyglucose positron emission tomography computed tomography which detected primary malignancy of the cervix with regional nodal and right knee joint metastasis. To our knowledge, this is the first reported case of cervical malignancy with solitary skeletal metastasis involving the knee joint. The report also discusses overall incidence of malignant arthritis.
