Pitfalls of Iodine-131 Whole-Body Scan Mimicking Metastases in Differentiated Thyroid Carcinoma: A Case Series.

Thyroid cancer is the most common endocrine malignant tumor and accounts for 1% of all cancers. Management of differentiated thyroid carcinoma is total thyroidectomy, followed by iodine-131 (I-131) radioactive iodine (RAI) therapy for thyroid remnant tissue. I-131 whole-body scan helps in the follow-up evaluation in remnant, residual, and recurrence cases. Principle of uptake of I-131 is through sodium-iodide symporter expression on the cells. Physiological uptake of iodine is usually seen in salivary glands and gastrointestinal tract, and false-positive uptakes are seen in lesions such as mucinous cystadenoma, struma ovarii, hepatic, renal, thymic, and meibomian cysts. Here, we present the review of literature of series of cases observed in our department presenting with false-positive uptake of RAI in vertebral hemangioma, lipoma, sinusitis, teratoma, and uterine leiomyoma.

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.

A Rare Finding of Pancreatic Involvement in a Case of Burkitt's Lymphoma.

Burkitt's lymphoma (BL) is a highly aggressive type of B-cell non-Hodgkin lymphoma. BL commonly occurs in children of age 4-7 years and is uncommon in adults, with a worse prognosis. Patients often present with a rapidly growing mass typically involving the abdomen (liver and spleen) and head and neck (nodes, jaw, and facial bones). Pancreas involvement is very rare and very few case reports have been documented so far. Fluorine-18 positron emission tomography/computed tomography (F-18 PET/CT) is a whole-body survey commonly used for initial staging evaluation. Here, we present an interesting case of BL in an adult female of 43 years, who presented with swelling in the left submandibular region after tooth extraction with multiorgan involvement found on F-18 fluorodeoxyglucose PET/CT.

An Uncommon Presentation of Leptomeningeal Metastases in Breast Carcinoma Detected by F-18 FDG PET/CT.

Leptomeningeal carcinomatosis is a manifestation in which tumor cells migrate into meninges. Breast carcinoma presenting with leptomeningeal metastases is a rare phenomenon that can occur in an isolated form as well as with coexistent parenchymal brain metastases. The gold standard for diagnosis is cerebrospinal fluid analysis, while contrast-enhanced magnetic resonance imaging is the most commonly used imaging modality. Nuclear medicine imaging with flourine-18-fluorodeoxyglucose positron emission tomography/computed tomography has proved to be useful in detecting leptomeningeal metastases and, at times, even before anatomical changes occur. Here, we present a case of breast carcinoma presenting with both pachymeningeal and leptomeningeal metastases 10 years after treatment.

Role of 99mTc-sestamibi Scintimammography in Predicting Response to Neoadjuvant Chemotherapy in Locally Advanced Breast Cancer: A Prospective Study.

Background: Neoadjuvant chemotherapy (NACT) is the first line of management for locally advanced breast cancer (LABC). However, chemoresistance is prevalent in 18%-50% of the cases. One of the important and most studied causes of chemoresistance is P-glycoprotein (Pgp) expression. 99mTc-sestamibi scintimammography may serve as a useful imaging tool to predict Pgp expression, thereby response to NACT. Aim: The aim was to study the role of 99mTc-sestamibi scintimammography in predicting response to NACT in treatment-naive, biopsy-proven LABC patients. Materials and Methods: 99mTc-sestamibi scintimammography (early and delayed images) was performed on a total of 34 patients. Eight patients were lost to follow-up, and only 26 (25 females and 1 male) patients were available for final analysis, with a mean age of 49.7 ± 10.7 years. 99mTc-sestamibi washout rate (WOR) (%) and T/B buildup were calculated. Pre-NACT and Post-NACT tumor sizes were measured clinically, and a % decrease in tumor size was calculated. The WOR and T/B buildup values were correlated with the % decrease in tumor size. Results: We found a statistically significant negative correlation between WOR (%) and % decrease in tumor size and a statistically significant positive correlation between T/B buildup and % decrease in tumor size. Furthermore, we found a positive correlation between the early T/B ratio and the Ki-67 index (P = 0.22). Conclusion: Early categorization of responders and nonresponders can help in optimal therapy planning. 99mTc-sestamibi scintimammography can serve as an imaging marker for Pgp expression, thereby predicting clinical response to NACT in LABC patients. Further studies with larger sample sizes are warranted to consolidate the above findings.

Utility of 18F-FDG PET/CT in Management of Pancreatic and Periampullary Masses-Prospective Study from a Tertiary Care Center.

Characterizing a pancreatic or periampullary mass lesion as benign or malignant on conventional imaging is difficult due to overlapping morphological features. 18F-FDG PET/CT is a molecular imaging technique with reportedly higher sensitivity and specificity in the differentiation of benign and malignant pancreatic and periampullary masses. In this prospective study, we evaluated the utility of 18F-FDG PET/CT in patients with recently diagnosed pancreatic and periampullary masses. Based on FDG uptake pattern, diffuse or absent uptake was considered benign and focal increased uptake as malignant. Among the 32 patients included in the study, pathological examination confirmed 25 as positive for malignancy and the remaining 7 as benign etiology. Based on FDG uptake pattern, sensitivity, specificity, PPV, NPV, and accuracy of the study were 92%, 42.8%, 85.2%, 60%, and 81.3% respectively. 18F-FDG PET/CT had a statistically significant higher detection rate in the evaluation of regional lymph nodes and distant organ metastases compared to radiological imaging. In 7/25 (14%) malignant cases, 18F-FDG PET/CT detected additional distant metastases which were not detected by conventional imaging and thus resulting in change in management from curative resection to palliative therapy. To conculde, 18F-FDG PET/CT uptake pattern can characterize pancreatic and periampullary masses as benign or malignant with a relatively good accuracy. Using 18F-FDG PET/CT for initial staging of pancreatic and periampullary cancer helps in appropriate staging and optimal selection of treatment modality compared to conventional imaging techniques.

Assessment of Gastric Dysmotility Using Standardized Tc-99m Sulfur Colloid-Labeled Rice Cakes in Diabetic Patients.

Background: Diabetes mellitus is a common lifestyle disease where patients suffer from gastric dysmotility, which is usually underdiagnosed. The aim of this study was to evaluate the utility of Tc-99m sulfur colloid-labeled meal gastric emptying scintigraphy in Type 2 diabetic patients. Methods: A total of 43 patients and 30 controls, satisfying the inclusion criteria from March 2019 to August 2020, were included. Serial planar images were acquired in both anterior and posterior projections for an iso-time of 1 min at 1 min, 60 min (1 h), 120 min (2 h), and 240 min (4 h) after consumption of Tc-99m SC-labeled idly (rice cakes). The gastric emptying was considered delayed if there was <10% emptying at 1 h, <70% emptying at 2 h, and <94% emptying at 4 h. Results: The mean T1/2 was similar among cases (44.11 ± 10.52 min) and controls (49.56 ± 13.44 min, P = 0.056) while the mean gastric emptying at 1 h was slower in cases compared to controls, P = < 0.01. Two cases (4.6%) had delayed gastric emptying while none of the controls had delayed gastric emptying. T1/2 showed no association with duration of diabetes or HbA1c levels (P = 0.76, 0.45) and a weak correlation with fasting blood sugar (FBS) on the day of scan (R value = 0.18). Conclusion: In comparison to controls, diabetic patients had faster gastric emptying with no association with duration of diabetes or HbA1c levels and a weak correlation with FBS on the day of scan.

Utility of Fluorine18 Fluoro-2-deoxy-D-glucose Positron Emission Tomography/Computed Tomography in Metabolic Characterization of Solid Renal Mass Lesion and Localization of Extra Renal Lesions in the Body - A Prospective Study from the Tertiary Care Center in South India.

Purpose of the Study: Renal mass lesions in majority of the cases are due to malignant etiology and about one-third of them are reported with metastatic lesions at the time of presentation. Thus proper investigational workup is needed for staging and thereby treatment planning. The current fluorine18 fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography (F18-FDG PET/CT) study was designed to characterize renal mass lesions metabolically and identifying other metabolically active lesions in the body suggesting metastatic disease. Materials and Methods: A total of 24 patients (males - 18 and females - 6) with a mean age of 53.8 ± 12.3 years were recruited in this study for dual time-point PET/CT scan. All patients with renal mass lesions underwent contrast-enhanced CT prior to PET/CT. Metabolic parameters such as maximum standardized uptake value (max.SUV) with a cut off ≥2.5 and retention index (RI) of ≥10% were used to label the lesion as malignant and remaining less than cutoff as benign. The final diagnosis of lesion on imaging was confirmed with a histopathological examination (HPE). Results: Using max.SUV cut off value, 17/24 renal mass lesions were characterized as malignant and remaining 7/24 renal lesions of benign etiology. PET/CT showed sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were 80%, 75%, 94.1%, 42.8%, and 79.1%, respectively, by considering HPE as a gold standard. Nine patients were diagnosed with distant site involvement suggestive of metastases. Conclusion: F18-FDG PET/CT can efficiently characterize solid renal mass lesion as benign and malignant using metabolic parameters such as max.SUV and RI. In addition, whole-body survey identified distant site involvement in 25% of the patients, thus contributing change in management.

Preparation of 177Lu-PSMA-617 in Hospital Radiopharmacy: Convenient Formulation of a Clinical Dose Using a Single-Vial Freeze-Dried PSMA-617 Kit Developed In-House.

OBJECTIVE: In the recent time, endoradionuclide therapy for metastatic castration-resistant prostate carcinoma employing 177Lu-PSMA-617 has yielded encouraging results and several clinical trials with the agent are currently ongoing. Routine preparation of 177Lu-PSMA-617 patient doses can be made simpler and convenient, if the ingredients essential for radiolabeling are made available in a ready-to-use lyophilized form. METHODS: PSMA-617 freeze-dried kit was formulated and used for the preparation of 177Lu-PSMA-617 clinical dose with high radiochemical purity using low/medium specific activity 177Lu. Detailed radiochemical studies were performed to determine the maximum activity and volume of 177LuCl3, which can be added in the kit for the formulation of 177Lu-PSMA-617. Studies were also performed to determine the shelf life of the kit to ensure its long-term usage. Studies were performed in buffer as well as human serum medium to determine the stability of the 177Lu-PSMA-617 complex after storing in respective media up to 7 days postpreparation. About ten patient doses of 177Lu-PSMA-617 were administered, and posttherapy scans were acquired. RESULTS: The formulated freeze-dried kit of PSMA-617 could be radiolabeled with an average percentage radiochemical purity > 98.53 ± 0.38. The freeze-dried kit was found suitable for tolerating up to 0.5 mL of 177LuCl3 (in 0.01 N HCl) and specific activity of 555 MBq/µg (15 mCi/µg) for the preparation of the patient dose of 177Lu-PSMA-617. The 177Lu-PSMA-617 complex prepared using the freeze-dried kit of PSMA-617 was observed to maintain % radiochemical purity (RCP) of 96.74 ± 0.87 and 94.81 ± 2.66, respectively, even after storing up to 7 days in buffer and human serum, respectively. 177Lu-PSMA-617 prepared using the in-house formulated freeze-dried kit of PSMA-617 exhibited accumulation in metastatic lesions picked up in a pretherapy PET scan. Reduction in number as well as size of lesions was observed in posttherapy scans acquired after two months of administering the first therapeutic dose of 177Lu-PSMA-617. CONCLUSIONS: The freeze-dried kit of PSMA-617 could be used for the preparation of 177Lu-PSMA-617 with high radiochemical purity (>98%) in a reproducible manner. 177Lu-PSMA-617 prepared using the developed kit was successfully evaluated in patients suffering from metastatic prostate cancer.

An Uncommon Presentation of Extrapulmonary Tuberculosis Masquerading as Ovarian Malignancy in a Young Female.

Tuberculosis (TB) is chronic granulomatous infection caused by bacteria, Mycobacterium tuberculosis, which primarily involves the lungs. Abdominal TB is an extrapulmonary disease which can mimic malignancy, especially in women with ascites, weight loss, and high cancer antigen-125 levels. Here, we report a case of young female, where clinical and radiological features were suggestive of ovarian malignancy. However, the pattern of uptake on flourine-18 fluorodeoxyglucose positron emission tomography/computed tomography raised the suspicion of a chronic infectious disease. The final diagnosis was confirmed as TB by cytology and started on antituberculous treatment. She had a good response and remission of lesions after 4 months of treatment.

Utility of Short-Acting Intravenous Insulin Therapy in Preparation of F-18 Fluorodeoxyglucose Positron Emission Tomography Computed Tomography Scan in Cancer Patients Incidentally Detected with High Blood Glucose Levels on the Day of Test.

BACKGROUND: In diabetic (DM) patients, hyperglycemia degrades image quality in F-18 FDG PET CT by altering bio-distribution of FDG in the body and augmenting soft tissue and muscular uptake. We intend to evaluate the use of short acting I.V insulin in minimising the rescheduling of patients detected with FBG>160 mg/dL on the day of scan. AIM AND OBJECTIVES: To show the utility of short acting IV insulin therapy in preparation of cancer patients incidentally detected with high blood glucose levels for F-18 FDG PET CT scan, (>160mg/dL) and to compare the obtained image quality with patients detected with fasting blood glucose level (FBG) <100mg/dL and <160 mg/dL, using visual and semi quantitative methods. MATERIAL AND METHODS: 613 cancer patients referred for PET CT were divided into 3 groups, Group I (n=30): known diabetics (DM) or incidentally diagnosed with FBG >160 mg/dL, Group II (n=349): DM patients with FBG <160 mg/dL (100-160mg/dL), Group III (n=234): Non DM patients FBG <100mg/dL. In Group I short acting insulin was given intravenously using a sliding scale, post insulin after 90 minutes F-18 FDG (radiotracer) injection was given and PETCT scan was obtained 60 mins post radiotracer injection. Qualitative image analysis was done using biodistribution score and quantitative analysis was done by chi square test, ANOVA (analysis of variance) and paired t-test. RESULTS: In group I patients post insulin there was significant decrease in FBG levels (216±22.2 to 136±13.4mg/dL) and acceptable image quality. Comparison of quantitative parameters (mean and maximum SUV calculated by drawing ROI around brain, heart, liver, muscle, subcutaneous fat) among the 3 groups showed significant intergroup difference with p value <0.05. CONCLUSION: This short acting I.V insulin protocol is safe and can be used to obtain optimal quality F-18 FDG PET CT scan images by alleviating the need for rescheduling patients though they present with high glucose levels.

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.

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.

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%.

Unilateral Graves' Disease: The Lesser Known.

BACKGROUND: Here, we present a retrospective study conducted from 2009 to 2018, which showed the presence of unilateral uptake of radioactive tracer on 99mTc thyroid scintigraphy scan in 15 patients with Graves' disease. MATERIALS AND METHODS: All these patients had either clinical features of Graves' disease or elevated thyroid hormone levels along with ultrasonographic features, showing either normal thyroid gland or diffuse thyroiditis. The scintigraphic features revealed increased uptake in one lobe of the thyroid gland with the other lobe being normal. RESULTS: Of the 15 patients, 13 were females and two were males. The mean age of the patients was 47 years with standard deviation of 3.4 years (range 26-70 years). Eight of the 15 patients had increased uptake on the right lobe and seven had increased uptake in the left lobe. CONCLUSION: This study shows that there exists an entity called unilateral Graves' disease which should be further evaluated.

Whole-body 18F-fluorodeoxyglucose positron emission tomography-computed tomography (18F-FDG PET/CT) for staging locally advanced breast cancer: A prospective study from a tertiary cancer centre in south India.

Background & objectives: Locally advanced breast cancer (LABC) is associated with substantial risk of occult metastases. The patients with LABC have high rate of systemic relapse, suggesting inadequacy of the current conventional staging in detecting the occult metastatic spread. 18F-fluorodeoxyglucose (FDG) positron emission tomography-computed tomography (PET/CT) is a new modality in the staging of breast cancer patients. Hence, this study was conducted to evaluate the role of 18F-FDG PET/CT in initial staging of LABC and to compare it with conventional methods. Methods: This prospective study included biopsy-confirmed female patients diagnosed with LABC meeting the selection criteria and attending surgical, medical and radiation oncology departments of a tertiary care centre in south India, from April 2013 to December 2014. Conventional workup included serum chemistry, mammogram, bone scan, contrast-enhanced CT (CECT) chest and upper abdomen and ultrasound abdomen and pelvis. All patients following conventional workup underwent 18F-FDG PET/CT. Results: In this study, 61 women with LABC underwent both conventional workup and 18F-FGD PET/CT. The 18F-FDG PET/CT, in comparison to conventional workup, revealed unsuspected N3 nodal disease in 11 more patients, revealed distant metastasis in seven more patients and also detected extra sites of metastasis in five patients. The sensitivity, specificity, positive predictive value, negative predictive value and accuracy of PET/CT to detect distant metastasis were 95, 98, 95, 98 and 97 per cent, respectively, whereas the sensitivity, specificity, positive predictive value, negative predictive value and accuracy of conventional imaging to detect distant metastasis were 65, 93, 81, 84 and 84 per cent, respectively. Interpretation & conclusions: The 18F-FDG PET/CT was found to be more accurate than conventional imaging for staging and modified stage and treatment in 30 and 38 per cent of patients, respectively. It was particularly useful in detecting occult distant metastasis and N3 nodal disease with an added advantage of examining whole body in single session. However, CECT chest was superior over 18F-FDG PET/CT for detecting pulmonary metastasis.

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.

Intracranial meningioma, mimicking brain metastasis on 18F sodium fluoride bone scan in a case of carcinoma cervix.

Bone scintigraphy (BS) is a well--established commonly used imaging modality for staging and follow--up evaluation of cancer patients. Occasionally, BS may show asymptomatic unusual extraosseous lesions in the body which may or may not be related to primary disease. We here present an interesting case of carcinoma cervix in whom 18F sodium fluoride positron emission tomography-computerized tomography (PET-CT) bone scan detected an intracranial lesion. Initially, this lesion was suspected as brain metastasis; however, later on, combined PET--CT images and contrast-enhanced CT confirmed this lesion as calcified falcine meningioma in the right posterior parietal region.

Polyostotic Paget's disease mimicking multiple skeletal metastases in planar bone scintigraphy in a patient with carcinoma of breast.

The author describes the utility of serial bone scintigraphy to rule out metastatic bone disease in a patient with carcinoma of breast with Paget's disease mimicking multiple skeletal metastases.