Technetium-99m Methoxyisobutyl Isonitrile Stress MPI in Suspected Coronary Artery Disease Patients: A Prospective Study to Evaluate Clinical Significance of Adenosine-induced ECG Changes.

Purpose: The purpose of this study is to evaluate the adenosine pharmacological stress-induced electrocardiogram (ECG) changes and their association with stress-induced ischemic defects on myocardial perfusion scintigraphy (MPS) in the evaluation of coronary artery disease (CAD) and to evaluate event-free survival among patients with positive and negative ECG/MPS image findings. Methods: A total of 100 patients were examined using stress MPS from March 2020 to August 2021. Stress-induced ECG changes during adenosine infusion were evaluated. The summed stress score (SSS) was evaluated to identify ischemic defects in myocardium. Association of stress ECG changes and scintigraphic results was evaluated. Results: Out of 100 patients, stress ECG changes during adenosine infusion were seen among 34 patients, whereas 66 patients had normal ECG findings. Positive stress MPS findings with SSS >3 were seen in 22 patients, whereas 78 patients had SSS ≤3. There was no agreement between stress ECG changes and MPS findings with Cohen's kappa coefficient (κ) = -0.023, whereas there was mild agreement between stress ECG changes and SSS >7 with κ = 0.105. Median follow-up of 11 months showed more events among patients with positive ECG changes than negative ECG changes. Conclusion: Adenosine, pharmacological stress is safe to use, but few patients might experience some minor and transient symptoms. Adenosine may induce ECG changes in patients with or without positive MPS findings. Patients with concordant positive findings need aggressive cardiac care, whereas patients with small or no defects on MPS need close monitoring.

Metachronous Second Primary Malignancies in Known Breast Cancer Patients on 18F-Fluoro-2-Deoxyglucose Positron Emission Tomography-Computerized Tomography in a Tertiary Care Center.

INTRODUCTION: Breast cancer is the most common malignancy among women all over the world, which accounts to 25% of all cancers. In known cases of breast cancer, the risk of developing another denovo malignancy is more when compared to low risk groups, which might be due to common environmental risk factors, treatment induced risk factors, Genetic susceptibility for mutations, presence of cancer syndromes or better detection due to close surveillance. OBJECTIVE: To study the profile of Metachronous 2nd primary malignancies suspected on 18F-FDG PET CT in known Breast cancer patients. In this Retrospective study from January 2014 to April 2018, all the consecutive patients with known Breast cancer, who were referred to Nuclear Medicine department for 18F- FDG PET CT for follow up evaluation were included. Suspected 2nd primary malignancies were correlated with Histopathological examination (HPE). RESULTS: During the study period, a total of 233 Breast cancer patients (all are females), with a mean age of 54.2+13.4 years were studied. On 18F-FDG PET CT scan, suspicion for 2nd primary malignancy was observed in 37 patients. HPE was done in 28/37 patients at the site of suspected lesions. 15/28 were positive for second malignancy, and remaining 13/28 were either a benign pathology or a part of metastatic disease from the primary breast cancer. The sites of 2nd primary malignancies included Contralateral breast in 8/15 (53.3%), Ovary in 2/15 (13.3%), Endometrium in 2/15 (13.3%), Lung in 1/15 (6.6%), Stomach in 1/15 (6.6%) and Urinary bladder in 1/15 (6.6%) patients respectively. The incidence of metachronous 2nd primaries in breast cancer is 67.3 per 1000 breast cancer patients. CONCLUSION: Metachronous second primary cancers in breast cancer patients are not very rare. A high imaging suspicion on 18F-FDG PET CT helps in early detection of 2nd primary cancer, thereby facilitating early and appropriate management.

Unusual Metastases in Papillary Microcarcinoma of Thyroid.

Papillary carcinoma thyroid is the most common type of thyroid cancer. Papillary thyroid cancer metastasizes commonly to regional lymph nodes, distant organ involvement is to lungs and bone are rare and is associated with poor prognosis. Metastases to intra-abdominal organs are extremely rare. Here, we report a case of 50-year-old female diagnosed with papillary microcarcinoma thyroid who initially treated total thyroidectomy, later presented with metastasis to liver, bone, left adrenal gland, and bilateral lungs. The functioning metastasis was diagnosed by Iodine-131 whole-body scan and later treated with radioiodine.

F-18 Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography in the Evaluation of Intradiploic Epidermoid Cyst.

Epidermoid cysts are benign rare congenital cysts which typically present between 3rd and 5th decade of life. They mostly arise from cerebellopontine angle or parasellar region, but sporadic cases arise from cranial dipole. Here, we present a case of 42-year-old female with painful soft swelling in the left frontal region, which on F-18 fluorodeoxyglucose (FDG) positron emission tomography-computed tomography is well-circumscribed non-FDG avid lesion. The patient underwent total resection of the cyst, and the defect produced by space-occupying lesion was repaired by cranioplasty.

Hyperphysiological F-18 Fludeoxyglucose Uptake of Masticator Muscles in a Case of Awake Bruxism.

F-18 FDG is a tracer of glucose metabolism, which is commonly used in PET/CT for oncological diagnosis and staging. F-18 FDG uptake represents the glycolytic activity in the cell. Physiological FDG concentration may be noted often in the muscles of head and neck, tongue, muscles on mastication, extra ocular muscles due to eye movements, cricopharyngeus and posterior cricoarytenoid muscles on phonation, etc. Here we report a case of Awake Bruxism, who came for F-18 FDG PET/CT for evaluation of Pyrexia of unknown origin (PUO), showing intense F-18 FDG uptake symmetrically in masticator muscles. Bruxism is a habit of involuntary spasmodic grinding or clenching of teeth. Many factors like psychosocial, genetic, certain medications and sleep disorders are known to be associated with bruxism. Therefore knowledge of physiological F-18 FDG uptake as well as artifactual uptake is essential for nuclear medicine physicians, to avoid ambiguity in diagnosis.

18F-Fluorodeoxyglucose Positron Emission Tomography-computed Tomography in Evaluation of Large Vessel Vasculitis.

18F-fluorodeoxyglucose positron emission tomography-computed tomography (18F-FDG PET-CT) is a rapidly evolving hybrid imaging technique in evaluation of infection and inflammation. Usually, functional changes often precede anatomical changes. 18F-FDG PET-CT, a noninvasive diagnostic test and it is useful for the early detection of inflammation. Most of the large vessel vasculitis patients present with nonspecific signs and symptoms, which are difficult to diagnose clinically. Here, we discuss three cases of large vessel vasculitis with different clinical presentations, identified by 18F-FDG PET-CT scan.

Atypical Parathyroid Adenoma with Multiple Brown Tumors as Initial Presentation: A Rare Entity.

Brown tumors seen in hyperparathyroidism are rare, non-neoplastic lesions because of abnormal bone metabolism, and they can mimic benign bone tumors or malignancy. Although biopsy is considered as the gold standard for diagnosis, it can be inconclusive. As the diagnosis of brown tumors is often challenging, a high index of suspicion is essential for diagnosis. We present a case of 21-year-old woman who presented with multiple painful bony lesions, which were initially misdiagnosed as fibrous dysplasia. Due to persistent bone pain and deterioration in her physical mobility, she was referred to tertiary care centre. After thorough clinical workup, she underwent Tc-99m methylene diphosphonate bone scintigraphy that raised strong clinical suspicion of hyperparathyroidism and brown tumors. Subsequently, Tc-99m-methoxy isobutyl isonitrile (MIBI) parathyroid scintigraphy revealed a solitary MIBI avid focal lesion, suggestive of left inferior parathyroid adenoma. Later parathyroidectomy was performed and histopathological examination confirmed it as atypical parathyroid adenoma.