Purpose of the Study: The purpose of this study was to study the role of equilibrium radionuclide angiography (ERNA) in the assessment of left ventricular (LV) mechanical dyssynchrony in patients with dilated cardiomyopathy (DCM), by correlating the findings with electrocardiographic parameters and speckle-tracking echocardiography (STE). Methods: This was a prospective observational study. A total of 55 patients with a mean age 42.5 ± 11 years (range: 19–61 years) diagnosed with DCM underwent ERNA and echocardiography sequentially. On ERNA, phase images of LV were obtained, and standard deviation of LV mean phase angle (SD LVmPA) was derived to quantify intra-LV mechanical dyssynchrony (ILVD). Similarly, on STE, “dyssynchrony index” was calculated as the standard deviation of time-to-peak systolic circumferential strain (SDCS) of the six mid-LV segments. The cutoff values used to define mechanical dyssynchrony were SD LVmPA >13.2° (or >27.1 ms) and SDCS >74 ms on ERNA and STE, respectively. The results obtained from the two modalities were then compared. Results: Speckle-tracking analysis could be done on the echocardiographic data of only 42 patients. Paired data from ERNA and STE studies of these 42 patients (26 males and 16 females) were compared, which showed no significant difference in the detection of ILVD (P = 0.125). The two modalities showed good agreement with Cohen's kappa value of 0.78 (P < 0.0001). SD LVmPA and SDCS values showed moderately strong linear correlation (ρ = 0.69; P < 0.0001). No significant association of mechanical dyssynchrony on ERNA or STE was found with QRS duration and with the presence or absence of left bundle branch block. ILVD was also found to be negatively correlated with LV ejection fraction. Conclusion: ERNA is comparable to STE for the assessment of LV mechanical dyssynchrony.

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.

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.

Purpose of the Study: To assess the efficacies of Tc-99m glucoheptonate single photon emission computed tomography-computed tomography (Tc-99m GHA SPECT-CT) and N-13 ammonia positron emission tomography-computed tomography (N-13 NH₃PET-CT) in detecting recurrent glioma. Materials and Methods: Fifty-five consecutive, histologically proven, and previously treated glioma patients (age, 38.9 ± 12.2 years; 61.8% males) presenting with clinical suspicion of recurrence were evaluated with Tc-99m GHA SPECT-CT and N-13 NH₃PET-CT. Images were evaluated both qualitatively and semiquantitatively. A combination of clinicoradiological follow-up, repeat imaging, and/or biopsy (when available) was considered as the reference standard. Results: Based on the reference standard, 28/55 (50.9%) patients had recurrence. Sensitivity, specificity, positive predictive value, negative predictive value, accuracy of Tc-99m GHA SPECT-CT, and N-13 NH₃PET-CT were 85.7%, 85.2%, 85.7%, 85.2%, 85.5% and 78.6%, 88.9%, 88.0%, 80.0%, 83.6%, respectively (concordant findings in 46 patients). The performances of the two modalities were equivalent both in overall and subgroup McNemar analyses (P = 0.508, overall; P = 0.687, low grade; P = 1.000, high grade). Conclusion: Tc-99m GHA SPECT-CT is an alternative imaging modality equally efficacious as N-13 NH₃PET-CT in detecting recurrent glioma.

Aim: The aim of the study is to evaluate the value of thyroid-stimulating hormone (TSH)-stimulated thyroglobulin (sTg) measurements by the end of the 1^st-year postablation in differentiated thyroid cancer (DTC) patients with biochemical non complete response (indeterminate and incomplete response). Patients and Methods: One hundred patients with DTC underwent near-total thyroidectomy and radioactive remnant ablation by iodine-131 (I¹³¹) with regular follow-up every 6 months during the first 2 years and at 6–12-month intervals thereafter by I¹³¹ whole-body scan (WBS), neck ultrasound, and sTg measurement in the hypothyroid state (TSH >30 mU/L). Patients were divided according to the imaging findings and sTg level into three groups: excellent response (ER) – no evidence of disease by imaging and sTg <1 ng/mL, indeterminate or acceptable response (AR) – nonspecific findings on imaging studies and sTg < 10 ng/mL, and incomplete response (IR) – patients with incomplete structural and/or incomplete biochemical response (sTg > 10 ng/mL). Results: The follow-up at 6-month postablation showed ER in 3 (3%) patients, AR in 29 (29%) patients, and IR in 68 (68%) patients. The second follow-up at 9–12-month postablation showed dramatic biochemical response with ER, indeterminate, and IR in 50 (50%), 34 (34%), and 16 (16%) patients, respectively, and 14 (14%) patient had structural recurrence. This change is highly statistically significant (P = 0.00). In the last follow-up (ranges from 3 to 10 years), 53 (55.8%) patients achieved ER, 42 (44.2%) AR and no patient with non complete response. The change in patients with IR between the second and the last follow-up is also statistically significant (P = 0.001). Conclusion: sTg measurement by the end of the 1^st year is more reliable in the follow-up of patients with DTC and biochemical non complete response and considered significant predictor of disease-free status. Patients with biochemical IR still have the chance to achieve ER or AR by the passage of time without additional therapies.

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.

The authors report a series of cases of treated nodal, solid malignancies showing persisting physical residue after completion of treatment with 18-F fluorodeoxyglucose positron emission tomography-computerized tomography showing non-avid status conjuring a nondisease desmoplastic residue over morphological disease.

Thyrotoxicosis can occur in the setting of differentiated thyroid cancer due to functioning metastases. Here, we report a case of a 63 year old woman with papillary carcinoma thyroid who underwent total thyroidectomy and defaulted for further scheduled treatment with high dose radioactive iodine therapy. 2 years after total thyroidectomy, she presented with signs and symptoms of thyrotoxicosis and a scalp swelling on the right side of frontal region. Excision biopsy revealed metastatic deposits of papillary carcinoma thyroid. Even after withdrawal of thyroxine, her serum thyrotropin did not rise and thyroglobulin levels were high, raising the suspicion of high volume tumour burden. I-131 whole body scan was done and it revealed radio iodine avid cervical lymph nodes along with functioning lung and skeletal metastases.

Edge packing is a kind of nonuniformity artifact, which usually appears as an accumulation of counts at the edge of the field of view compared to the central region. The common causes of edge packing artifact in the image are defective collimator, noncalibrated photomultiplier tube (PMT), and improper adjustment of deflector plates of CRT. We hereby discuss the occurrence of edge packing artifact due to a problem with the PMTs in the anterior head of gamma camera system during acquisition of bone scintigraphy which mimics as pathological lytic–sclerotic lesion during whole-body image at anterior acquisition. The artifact was successfully removed after the replacement of malfunctioning PMTs.

Carcinoma of the sigmoid colon presenting in an inguinoscrotal hernia is uncommon. Many of the cases seen in literature were diagnosed only intraoperatively, as most of them had misleading presentations. We report a case of carcinoma of the sigmoid colon in an incarcerated inguinoscrotal hernia with imaging findings of 18F-FDG PET/CT along with a brief review of the literature.

Osteoid osteoma (OO) of distal fibula is extremely rare, and only few cases are reported in the literature. We report a case of OO of distal fibula and its surgical management at our tertiary care hospital.

Peritoneal lymphomatosis is relatively uncommon cause of diffuse malignant peritoneal disease, and differentiating it from other causes of diffuse peritoneal disease such as peritoneal carcinomatosis is often difficult on imaging. Common findings observed in peritoneal lymphomatosis in contrast to other etiologies include frequent nodal involvement and splenomegaly. We present a case of diffuse peritoneal disease along with ovarian lesions in the absence of abdominal lymphadenopathy or splenomegaly on fluorodeoxyglucose positron emission tomography–computed tomography in the setting of elevated cancer antigen-125 levels, mimicking primary ovarian malignancy causing peritoneal carcinomatosis, which was finally proven to be lymphoma.

Hyperparathyroidism and concurrent thyroid nodular disease are prominent. In contrast, concomitant papillary thyroid cancer and hyperparathyroidism are uncommon (1%–2%). Parathyroid adenomas in unusual locations are difficult to detect by conventional diagnostic imaging. ^99mTc-sestamibi single-photon emission computed tomography/computed tomography (SPECT/CT) has increased the localizing success rate of these lesions since it provides specific functional and anatomical information, improving exploratory parathyroid surgery planning and decreasing operative time, unnecessary dissections, complications, and morbidity. We confirmed its usefulness in a patient with an occult parathyroid adenoma that was clearly identified by ^99mTc-sestamibi SPECT/CT 2 weeks after a thyroidectomy for papillary carcinoma. The SPECT/CT results allowed us to successfully perform efficient reexploration of the thyroid bed, in a retroesophageal parathyroid adenoma by minimally invasive surgery.

Granulomatosis with polyangiitis (GPA) can be classified as classic triad of organ involvement consisting of lungs, upper respiratory tract/sinuses, and kidneys; limited which is not having the full triad; or widespread with additional organ involvement for example prostate, spleen, skin, eyes or peripheral nervous system and occasionally other organs. GPA is associated with increased 18F-fluorodeoxyglucose (FDG) uptake on positron emission tomography/computed tomography (PET/CT). PET/CT has the advantages of whole-body imaging and detecting metabolic abnormality before structural changes. FDG PET/CT is used to assess the extent of the disease in GPA and can detect site of occult disease involvement where there are metabolic evidence of defined organ involvement with no CT or clinical evidence. This may result in upgrading of the disease from limited to classic triad or from classic triad to widespread.

Encephalocraniocutaneous lipomatosis (ECCL) is a rare disorder and its clinical presentation constitutes a classic triad of the skin, ocular, and central nervous system involvement. We discuss the ¹⁸F-fludeoxyglucose positron-emission tomography/computed tomography findings of an 11-year-old boy with ECCL and drug refractory epilepsy.

Endometriosis is commonly associated with chronic pelvic pain and its presentation varies between individuals. The only way to confirm the presence of endometriosis is via keyhole or open surgery. In the presence of hematuria, deep endometriotic infiltration needs to be considered. We share an interesting case highlighting the role of ¹⁸F-fluorodeoxyglucose positron emission tomography-computed tomography in evaluating a posterior urinary bladder wall lesion and hypodense liver lesions in a middle-aged woman with presenting with frank hematuria in the background of treated cervical intraepithelial neoplasia and adenomyosis.

The primary hyperparathyroidism (PHPT) is a result of high levels of parathyroid hormone and serum calcium, the most frequent cause is a solitary parathyroid adenoma. Double parathyroid adenoma is <5% of the PHPT. Intrathyroidal parathyroid adenoma (IPA) occurs<3.2%. We present a case of 58-year-old female with persistent primary hyperparathyroidism due to a second undetected IPA, suspected by ultrasound and confirmed by ^99mTc sestamibi single-photon emission computed tomography/computed tomography.

We report a 44-year-old female patient diagnosed with neuropsychiatric systemic lupus erythematosus and probable ischemia secondary to vasculitis in the speech motor region (Broca's area). After corticosteroid treatment, the patient recovered the speech, presented clinical improvement, and SISCOM showed reperfusion of the ischemic area (luxury perfusion).

We present a case of endometrioid carcinoma metastasis in the bladder mimicking as the second primary of urinary bladder on ¹⁸F-fluorodeoxyglucose positron-emission tomography/computed tomography (¹⁸F-FDG PET/CT). The presentations of bladder lesions on ¹⁸F-FDG PET/CT are varied, and rare presentations of common malignancies can pose a significant diagnostic challenge as in the index case and highlight the importance of histopathological examination to confirm any unusual FDG uptake confounding the diagnosis.

A 28-year-old female presented with an incidentally detected mediastinal mass, found on routine chest X-ray. ¹⁸F-fluorodeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT) was advised to plan course of further management. FDG-PET/CT findings were suggestive of an FDG-avid soft-tissue mass in the left posterior mediastinum in paravertebral location with left pleural effusion. Overall, PET/CT scan findings favored the possibility of a nerve sheath tumor. However, histopathology along with immunohistochemistry confirmed the diagnosis of Castleman disease.

Nivolumab, an immune checkpoint inhibitor, is a humanized anti-programmed death-1 monoclonal antibody that is used for the treatment of various cancers after second-line chemotherapy. We report a 23-year-old male with relapsed Hodgkin's lymphoma Stage IV treated with nivolumab. After 3 months of treatment, he developed watery diarrhea and cramping abdominal pain. Follow-up positron emission tomography-computed tomography scan showed complete metabolic resolution of the disease; however, there is bowel wall thickening and colonic distension with corresponding increased fluorodeoxyglucose uptake. These findings are related to immune-related adverse event associated with nivolumab treatment, i.e., secondary enterocolitis. These adverse events can be successfully treated if timely and appropriately diagnosed.