Myocardial perfusion imaging: A brief review of nuclear and nonnuclear techniques and comparative evaluation of recent advances Manish Ora, Sanjay Gambhir Indian Journal of Nuclear Medicine 2019 34(4):263-270 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.

Diagnostic accuracy of dual-time-point fluorodeoxyglucose-positron emission tomography/computed tomography in verification local recurrence in pancreatic cancer patients Esraa El-Kholy, Lobna Khaled Indian Journal of Nuclear Medicine 2019 34(4):271-277 Purpose: The aim of this study was to evaluate the accuracy of dual-time point in differentiating benign from malignant local recurrent lesions in pancreatic cancer. Patients and Methods: Thirty-four patients with pancreatic cancer (22 males and 12 females, mean age: 58.3 ± 10.3) who presented with soft-tissue lesions at the operative bed. Early whole-body positron emission tomography/computed tomography (PET/CT) and delayed imaging on the abdomen were performed. The maximum standardized uptake value (SUVmax) of the initial image (SUVmax E) and the delayed image (SUVmax D) were determined. A Retention Index (RI) was also calculated. These indices were correlated with histopathology and follow-up as reference criteria. Results: No significant statistical difference in SUVmaxE was found between benign and malignant lesions, while SUVmaxD and RI of the malignant lesions (mean 8.6 ± 2.7 and 35.8 ± 18.3, respectively) were significantly higher than those of benign ones (mean 3.3 ± 1.4 and-6.2 ± 15.2, respectively) (P < 0.005). With SUVmaxD 4.9, malignancy could be predicted with the highest sensitivity (95.8%) and accuracy (94.1%) between the whole parameters. The estimated negative and positive predictive values (PPVs) were 90.0% and 95.8%, respectively. A cutoff point 16 for RI showed higher specificity and PPV (100% and 100%, respectively). Forty-seven total (11 benign and 36 malignant) lesions were identified. Increased SUVmax is noted on delayed images in most of malignant lesions, except for two that maintained stationary. Conclusion: Dual-time-point 18F fluorodeoxyglucose-PET/CT seems to be a reliable additional method to differentiate between malignant and benign postoperative local soft-tissue lesions in patients with pancreatic cancer.

The Prognostic value of pretreatment gallium-68 DOTATATE positron emission tomography/computed tomography in irradiated non-benign meningioma Maciej J Pelak, Andrea d'Amico Indian Journal of Nuclear Medicine 2019 34(4):278-283 Purpose of the study: The purpose of this study was to evaluate the potential value of gallium-68 (Ga-68)-DOTATATE positron emission tomography/computed tomography (PET/CT) in predicting the risk of progression in nonbenign meningioma after definite irradiation. We retrospectively reviewed our patients with meningiomas who had the highest risk of progression: WHO histological Grade II and III tumors and with macroscopic disease as identified in Ga-68-DOTATATE PET/CT. Materials and Methods: Thirteen patients were included in this study. For each tumor, the following quantifiers were measured: maximum and mean standardized uptake volume (SUV), standard deviation, metabolic tumor volume (MTV), total lesion activity, and coefficient of variation. Each of the quantifiers except for maximum SUV was obtained with three different SUV thresholds: muscle based (ms), liver based (liv), and gradient based (gb). The quantifiers were analyzed in univariate Cox model for their prognostic value for progression-free survival (PFS) and overall survival (OS). Results: Mean follow-up of the patients was 28.2 months. The 2-year PFS and OS was 28.1% and 76.9%, respectively. The MTVgbwas a significant predictor for PFS (risk of progression of disease above vs. below the 34 cm3 threshold: 100% vs. 28.3%,P = 0.0003). Clinically, the male sex also influenced PFS (Hazard ratio =13.06; 95% confidence interval: 1.56–109.25;P = 0.018). The mean SUVms(P = 0.041) and SUVgb(P = 0.048) had a prognostic value for predicting the risk of death. Conclusion: Ga-68-DOTATATE PET/CT has potential to predict disease progression in nonbenign meningioma patients. Further prospective studies for validating and standardizing these findings are indicated.

Metachronous second primary malignancies in known breast cancer patients on 18F-fluoro-2-deoxyglucose positron emission tomography–computerized tomography in a tertiary care Center Ranadheer Gupta Manthri, Sai Moulika Jeepalem, VS Krishna Mohan, D Bhargavi, Narendra Hulikal, Tekchand Kalawat Indian Journal of Nuclear Medicine 2019 34(4):284-289 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.

Exploring the role of intraoperative frozen section of the sentinel lymph node in the management of early-staged oral tongue cancers Arvind Krishnamurthy, Saket Mittal, Krishna Kumar Ramachandran Indian Journal of Nuclear Medicine 2019 34(4):290-294 Background: The present study aims to explore the role of sentinel lymph node biopsy (SLNB) with intraoperative frozen section in the management of early-staged oral tongue cancers. Materials and Methods: Fifty-two patients with clinical stages cT1/2N0 oral tongue cancers were included in the present study. The curative surgery was preceded by the performance of an SLNB using a dual technique. Results: The identification rate of sentinel lymph node (SLN) in this study was 98.07%. The sensitivity, specificity, positive predictive value (PPV), and the negative predictive value (NPV) of SLNB were 88.2%, 100%, 100%, and 94.5%, respectively. Further, the sensitivity, specificity, PPV, and the NPV of intraoperative frozen section of the SLN were 70.5%, 100%, 100%, and 87.5%, respectively. Conclusions: The addition of intraoperative frozen section could identify 70.5% of patients with occult metastasis. An intraoperative frozen section assessment of sentinel node has the potential to change the overall management of patients with early-oral tongue cancers.

Lung masses of unusual histologies mimicking malignancy: Flurodeoxyglucose positron emission tomography-computed tomography appearance Boon Mathew, Nilendu C Purandare, Sneha Shah, Ameya Puranik, Archi Agrawal, Venkatesh Rangarajan Indian Journal of Nuclear Medicine 2019 34(4):295-301 18F flurodeoxyglucose positron emission tomography-computed tomography (18F FDG PET-CT) is widely used in the evaluation of patients with lung mass suspicious for malignancy. In addition to malignancy, a variety of benign neoplasms and inflammatory lesions can arise in the lungs, many of which show increased FDG concentration, thereby mimicking malignancy. Awareness of the common mimics of lung cancer and a thorough understanding of their key imaging characteristics on CT as well as FDG PET is helpful in narrowing the differential diagnosis, eventually leading to appropriate therapy. In this article, we enlist these mimics and discuss their metabolic and morphologic characteristics and provide a pathophysiological basis for their FDG uptake.

Krukenburg tumors arising from rare primary sites: Role of 18F-fluorodeoxyglucose-positron emission tomography/computed tomography in management and outcome Kasturi Rangan, Manish Ora, Amrin Israrahmed, Sanjay Gambhir Indian Journal of Nuclear Medicine 2019 34(4):302-306 Krukenberg tumors described by Friedrich Ernst Krukenberg are still fascinating for their mysterious origin. It is known to be a rare entity and commonly originates from adenocarcinoma of stomach. We present three interestingly rare cases of this entity, revealed by 18F-fluorodeoxyglucose-positron emission tomography/computed tomography (F-18 FDG-PET/CT) scan and discuss how F-18 FDG-PET/CT can prognosticate, alter the course of treatment in such patients. Ovarian metastatic deposits were detected in patients with renal cell, duodenal, and gall bladder carcinoma. Three visits were possible in patient with duodenal cancer (favorable response to therapy), two visits in renal cell cancer (progressive disease pattern) and only single visit for gall bladder cancer. Potentials of F-18 FDG-PET/CT scan for Krukenberg disease is still in exploratory phase, but it's applications in diagnosis, disease monitoring, therapeutic response monitoring, and prognosticating are unparalleled with other imaging modalities.

Thyroid scintigraphy in fever of unknown origin Rashmi Ranjan Mohanty, Kanhaiyalal Agrawal, Bikash Ranjan Meher Indian Journal of Nuclear Medicine 2019 34(4):307-308 Thyroiditis is a very rare cause of fever of unknown origin (FUO). Thyroiditis presenting as only fever and weight loss is very rare. We present a case of FUO, which was later on confirmed as thyroiditis on thyroid scintigraphy.

Synchronous pancreatic solid pseudopapillary neoplasm masquerading as extralymphatic involvement on 18F-fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography in a case of Hodgkin's Lymphoma S Chandra Teja Reddy, V Venkatrami Reddy, D Bhargavi, B Deepthi, Suma Tammineni, Ranadheer Manthri, Tekchand Kalawat Indian Journal of Nuclear Medicine 2019 34(4):309-312 Solid pseudopapillary neoplasm (SPN) is a rare histopathologic variant of pancreatic tumors. Franz first described this tumor as a “papillary tumor of the pancreas, benign or malignant.” In 1996, the World Health Organization named this tumor as SPN of the pancreas. It has a female preponderance with a male-to-female ratio of 1:9. A 30-year-old female who is a known case of lymphocyte-rich classic Hodgkin's lymphoma underwent 18F-fluoro-2-deoxy-D-glucose (FDG) positron-emission tomography/computed tomography (PET/CT) for initial staging which showed intense metabolic activity in bilateral enlarged cervical and splenic hilar lymph nodes. Furthermore, intense metabolic activity was noted in hypodense lesion in the tail of the pancreas, and she was reported to be having Stage IIIE disease. Post chemotherapy, 18F-FDG PET/CT showed disappearance of all previously metabolically active lymph nodes but persisting metabolically active lesion in tail of the pancreas. Hence, we reported as complete metabolic response of Hodgkin's lymphoma as per the Lugano criteria with suspected synchronous primary in the tail of the pancreas. Post distal pancreatectomy, histopathological examination and immunohistochemistry revealed the pancreatic lesion as SPN. SPN of the pancreas itself is a rare tumor and the presence of SPN in a patient with Hodgkin's lymphoma as synchronous primary is very rare. Due to the high density of mitochondria and the hypervascular nature of the tumor, there is an accumulation of 18F-FDG in SPN tumor cells. Patients with SPN usually have a very good prognosis after surgery. The five-year survival rate is as high as 95%–97%.

Chronic venous insufficiency causing a diagnostic conundrum on Tc-99m bone scan done for osteosarcoma surveillance: Awareness is the key! Ravishankar Pillenahalli Maheshwarappa, Islam Ahmed Shehata Elhelf, Parren McNeely Indian Journal of Nuclear Medicine 2019 34(4):313-316 Bone scans are the most commonly used imaging technique to rule out local recurrence or metastasis during surveillance of malignant bone tumors after treatment. Although bone scans are very sensitive in detecting recurrence or metastasis, they are less specific. There are many nonmalignant conditions which can mimic either recurrence or metastasis on a Tc-99m bone scan. Therefore, physicians must be aware of such conditions to avoid unnecessary workup and invasive procedures. We present such an interesting case where chronic venous insufficiency mimicked either osteomyelitis or regional metastasis on a Tc-99m bone scan done for osteosarcoma surveillance.