Background: Preablative stimulated thyroglobulin (ps-Tg) is an important investigation in the follow-up of patients with Differentiated thyroid cancer(DTC) after surgery. Levels of ps-Tg >2–10 ng/ml have been suggested to predict metastasis to cervical and extracervical sites. There is still debate on the need for routine iodine whole-body scan (¹³¹I WBS) in the management of low-to-intermediate-risk DTC patients. Objective: We analyzed our data of patients with DTC who underwent total thyroidectomy to discuss the predictability of ps-Tg on metastatic disease on the ¹³¹I WBS. Materials and Methods: Retrospective analysis of patient records. Results: One hundred and seventeen patients with DTC (95 papillary thyroid cancer [71 had classic histology, 8 had tall cell variant, 16 had follicular variant] and 22 follicular thyroid cancer [18 minimally invasive, 2 hurtle cell, and 2 widely invasive cancers]) had undergone total thyroidectomy. All these patients underwent ps-Tg assessment and an ¹³¹I WBS. About 65% of them went on to have radioiodine ablation along with a posttherapy ¹³¹I WBS. We divided the cohort into four groups based on their ps-Tg levels: Group 1 (ps-Tg <1), Group 2 (ps-Tg 1–1.9), Group 3 (ps-Tg 2–5), and Group 4 (ps-Tg >5). None of the patients in Group 1, 7% of those combined in Groups 2 and 3 (2 out of 28 patients), and 26% (12 out of 47) of those in Group 4 had either cervical or extracervical metastasis. Those with extracervical metastatic disease to lungs and bones had a mean (standard deviation) ps-Tg value of 436 (130) and median of 500 ng/ml and those with cervical metastatic disease had a mean Tg value of 31 (64) and median 6.6 ng/ml. Conclusions: A ps-Tg value in the absence of anti-Tg antibodies <1 ng/ml reliably excludes metastatic disease in DTC, while a value >5 ng/ml has a 26% risk of having either cervical or extracervical metastasis.

Background: Thyroid cancer has been growing rapidly during the last decades. Radioiodine-131 (I-131) as an appropriate therapy modality is currently using in the treatment of cancer and hyperthyroidism diseases. This radiotracer is considered as a cause of oxidative DNA damage in nontarget cells and tissues. The aim of this study was to investigate the effects of curcumin and trehalose on the level of DNA double-strand breaks (DSBs) caused by I-131 in human lymphocytes. Materials and Methods: First, 6-mL blood samples were taken from each of the five volunteers. After 1 h of preincubation with the antioxidants, a total of 20 μCi I-131/2 mL (blood + NaCl) was added to each sample, and then, the samples were reincubated for 1 h. Lymphocytes were separated and the mean DSB levels were measured for each sample through γ-H2AX assay to evaluate the effects of antioxidants. Results: After 1-h incubation with I-131, the DSBs increased by 102.9% compared to the control group (0.343 vs. 0.169 DSB/cell; P = 0.00). Furthermore, compared to the control + I-131 group, curcumin and trehalose reduced the DSBs by 42% and 38%, respectively. There was a significant decrement (P = 0.00) in the levels of DSBs of the curcumin + I-131 and trehalose + I-131 subgroups compared to the control + I-131 subgroup. Furthermore, there was no significant relationship between the radioprotective effect of curcumin and trehalose (P = 0.95). Conclusion: The use of curcumin and trehalose as antioxidant can reduce the numbers of DSBs caused by I-131. Meanwhile, the radioprotective effect of curcumin was more than trehalose.

Introduction: Forced expiratory volume in one second (FEV₁) is an independent predictor for respiratory morbidity. Reports are varied and controversial substantiating the use of either lung perfusion (Q) or ventilation (V) scintigraphy as a single stage investigation to predict postoperative (ppo) FEV₁in patients scheduled for lung resection surgeries. It is said that there is no additional benefit by performing both V/Q scan. As per one of the recommendations, no further respiratory function tests are required for a lobectomy if the postbronchodilator FEV₁is >1.5 l. We wanted to study the ppo FEV₁in patients with FEV₁of <1.5 L scheduled for lung surgeries. Being a high-risk population, we wanted to assess (a) whether the ppo changes by this combined V/Q imaging and (b) whether the incidence of respiratory complication in the postoperative setting of this subgroup is different, (c) and study the short- and long-term clinical outcome. Materials and Methods: Fifty-two high-risk patients (with comorbidities) and borderline preoperative FEV₁of 1.5 L or less planned for lung resection were enroled in this prospective study. V and Q scans were performed, and tracer uptake percentage was tabulated. Results: Tracer uptake in each lung was quantitated. Manual method of ROI drawing is preferred in high risk patients with reduced pulmonary reserve over the automatic method. Based on uptake patterns by V/Q scans, 4 different types of patterns were tabulated. Eighty-eight percentage of centrally placed tumors showed the difference in uptake patterns. Chronic obstructive pulmonary disease patients usually showed more modest ventilatory defects (categorised as type 2 or 3). Lung tumours produce erratic uptake patterns (Type 4) which depend heavily on their location and extent. The range of FEV₁predicted was 0.6–1.38 L/min Conclusion: We recommend that combined imaging should be performed in patients with borderline pulmonary reserve to derive the benefit of surgery as it provides a realistic ppo FEV₁in patients with moderate to severely damaged lung. Centrally placed hilar or bronchial tumors (even those <2 cm in size), produce discrepancies in V/Q distribution pattern. Patient who was thought ineligible for surgery due to low baseline FEV₁may be actually be operable by this combined imaging if uptake pattern is better in V or Q scan with a good outcome. Accurate estimation of postop FEV₁in fact helps the surgical team to implement measures to prepare high risk patients to reduce postoperative complications, enable faster weaning from ventilatory support and ensure favourable prognosis.

Rationale: Prostate-specific membrane antigen positron emission tomography/computed tomography (PSMA PET/CT) is widely used for imaging of prostate cancer (PC) nowadays. However, appearance of bladder activity many a times hampers lesion detection vis-a-vis primary as well as regional nodes. We aimed to assess if early dynamic PET/CT can be a potential solution to this issue. Methodology: A total of 15 biopsy-proven PC patients who were referred to our department for ⁶⁸Ga-PSMA PET/CT for staging/restaging were prospectively studied. Dynamic PET/CT was done with on table intravenous injection of 2–3 mCi (74–111 MBq) of the radiotracer. Dynamic images were acquired over the pelvis with a frame time of 1 min for 10 min. Static images of 2 min per bed position were acquired between 45 and 60 min after injection. A 3D volume of interest was plotted on the primary lesion, involved nodes if any, pelvic bones at involved and uninvolved sites, gluteal muscles, and bladder. Results: Six patients were referred for staging and 9 for restaging. Mean age of 15 patients was 66.7 years, median prostate-specific antigen level was 17.25 ng/ml (Range 0.05–218), mean Gleason score was 8. All patients showed high target to nontarget ratio in the early dynamic images comparable to that seen on the delayed images in different sites (prostatic primary: n = 15 patients; lymph nodes: n = 10 patients; bone: n = 5 patients). All pathologic lesions showed tracer uptake within the first 3 min and reached maximum uptake during the dynamic study in last 3 min, indicating an increasing uptake pattern, whereas urinary bladder (UB) activity was insignificant within the first 3 min of dynamic imaging in all patients, reached maximum during last 3 min. SUV_maxwas significantly higher in primary lesions in the first 4 min compared to UB accumulation. Static images showed more tracer accumulation than dynamic images in primary, nodal, and bony lesions. However, all regional nodes seen on delayed static imaging also showed uptake on dynamic imaging. Conclusion: Early dynamic imaging ⁶⁸Ga-PSMA PET/CT can demarcate the primary tumor clearly due to nonaccumulation of bladder activity and appears to have comparable efficacy in detecting pelvic nodal sites as delayed imaging.

Orbital swelling comprises wide spectrum of pseudotumors, benign and malignant tumor. Malignant tumor may be primary or secondary tumor, and they constitute about 36% of orbital tumors in adult. Fluorodeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT) scan is extensively used in hematological malignancies and in solid tumors for staging, treatment response, and restaging. Recently, the use of FDG-PET/CT in orbital malignancies has gained importance. The aim of this pictorial essay is to illustrate few important orbital malignancies detected in F-18 FDG-PET/CT and discuss its role in assessing the primary lesion and associated systemic finding.

Metastases to cervical lymph node are fairly common in differentiated thyroid cancer. In iodine-refractory disease, the disease may persist in the thyroid bed, cervical lymph nodes, lungs, or the bones commonly. Retropharyngeal lymph nodal involvement in thyroid cancer is unusual and may even be the presenting complaint. We represent a case of iodine-refractory thyroid cancer with retropharyngeal lymph nodal involvement in addition to lung metastases.

The primary hypertrophic osteoarthropathy (PHOA) (pachydermoperiostosis) is a rare genetic/hereditary disease characterized by skin changes (pachydermia), clubbing of fingers and periosteal thickening (periostitis) with sub-periosteal new bone formation. Here we describe a case of an adolescent male who presented with clubbing and polyarthralgia. On evaluation with scintigraphy and SPECT-CT, he was diagnosed to have incomplete form of PHOA(skeletal manifestations without skin changes). The identification of incomplete form of primary hypertrophic osteoarthropathy which can be easily misdiagnosed as rheumatoid arthritis is discussed here.

We report here a case of unusually large brown tumor of mandible mimicking cherubism in a patient with secondary hyperparathyroidism (HPT). The patient is a young male with a large head and a protruding jaw with an open mouth appearance. Initial clinical appearance looked like cherubism. However further clinical, biochemical, and radiological evaluation revealed a large brown tumor in a case of prolonged secondary HPT, which was confirmed on histopathology. All of the typical advanced radiological features of HPT were noted, highlighting the severity of progression of the disease. This case emphasizes the need for surveillance of serum calcium levels on routine biochemical investigations as to enable an early diagnosis of HPT. With timely proper management, such cases should be on the decline in the future.

The authors report multiple giant bilateral pseudoaneurysms of pulmonary artery, also known as Rasmussen's aneurysms, which remained silent and unrevealed despite the large size and multiplicity unearthed by fluorine-18 fluorodeoxyglucose positron emission tomography/computerized tomography.

Discordant primary resistance and response of the metastatic lesions in the same individual coupled with splenic involvement in gastrointestinal stromal tumors (GISTs) are relatively uncommon. We herein report such a case of recurring GIST of the stomach that presented with the involvement of spleen with ¹⁸F-fluorodeoxyglucose positron emission tomography-computed tomography (FDG PET-CT) imaging documentation. Ultrasonography-guided fine needle aspiration cytology from the splenic and paravesical lesions demonstrated metastatic spindle cell tumor consistent with diagnosis of metastasis from GIST of the stomach. The splenic and the paravesical lesions appeared resistant to the conventional 400 mg of imatinib mesylate, while most other abdominopelvic metastatic lesions demonstrated good metabolic response on FDG-PET/CT, with the noteworthy findings of interlesional heterogeneity of the metastatic lesions in terms of differential primary response in the same individual.

18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) with computed tomography (CT) has become the standard of care in staging, restaging, and response assessment of various malignancies including malignant melanoma. However, nonspecific uptake of FDG can occur in infectious and inflammatory conditions and can mimic a tumor. We present here a case of gossypiboma of the axillary region with FDG uptake detected in a patient with malignant melanoma of the upper extremity and discuss the potential pitfalls of this entity on FDG-PET/CT.

Extrathyroidal manifestations of autoimmune thyroid disorders include thyroid-associated ophthalmopathy, thyroid dermopathy, and thyroid acropachy. Thyroid acropachy is an extreme manifestation of autoimmune thyroid disorder characterized by clubbing and swelling of fingers and toes, with or without periosteal reaction of the distal bones. We present a 50-year-old woman, posttreatment for carcinoma breast (6 years back) and referred for bone scan for generalized body ache. Bone scan findings resulting in detailed clinical evaluation prompted toward the suspicion of a thyroidal disease with ultimate diagnosis of Graves' disease.

Fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) is an established imaging modality in diagnosis and treatment response monitoring of sarcoidosis. Multisystemic involvement of sarcoidosis is characteristically seen on PET/CT; however, isolated organ involvement is rare. We describe here a case of a 52-year-old male with generalized muscle weakness, an extremely rare clinical manifestation of sarcoidosis.

Uterine carcinosarcomas, also known as malignant mixed mullerian tumors, are one of the rare and most aggressive neoplasms of the uterus. They have an aggressive course and can spread to distant organs. Owing to the low incidence of these tumors, the optimal adjuvant management after surgery is not well established. Many patients develop distant metastases during follow-up. An interesting case of uterine carcinosarcoma who developed metastases to the femur, tibia, and calcaneum during follow is presented.

We report a 47-year-old woman who developed an ischemic stroke with diplopia and dysarthria. Emergency computed tomography (CT) showed no pathological findings, and magnetic resonance (MR) showed mild ischemic-degenerative lesions. MR angiography and angiogram showed severe stenosis of both internal carotid and main intracranial arteries with plenty collateral vessels with “puff of smoke” suggesting a moyamoya disease (MMD). Brain perfusion single-photon emission CT showed global diminished perfusion in the brain lobes and a marked relative hyperperfusion in the cerebellum. However, brain ¹⁸F-fluorodeoxyglucose-positron emission tomography showed physiological metabolism in the brain cortex with only slightly relative cerebellar hypermetabolism. MMD is a well-known arterial pathology that frequently develops with only mild symptoms until the middle age. Functional neuroimaging findings indicate a mismatch between brain glucose metabolism and brain perfusion, probably due to neuronal subclinical chronic ischemia in the brain cortex with preserved viability of neurons.

Gout is a common metabolic disorder, typically diagnosed in peripheral joints. Tophaceous deposits in lumbar spine are a very rare condition with very few cases reported in literature. The following is a case report of a 52-year-old patient with low back pain, left leg pain, and numbness. Serum uric acid level was in normal range. magnetic resonance imaging, bone scan, and gallium-67 images suggested an inflammatory-infectious process focus at L4. After a decompressive laminectomy at L4–L5 level, histological examination showed a chalky material with extensive deposition of amorphous gouty material surrounded by macrophages and foreign-body giant cells (tophaceous deposits).

^99mTc diethylenetriaminepentaacetic acid (DTPA) renogram is a commonly performed evaluation postrenal transplant to assess graft function and for early detection of suspected immediate and late transplant-associated complications. Although several modalities can be utilized to detect perinephric collection in posttransplant period, the utility of ^99mTc DTPA single-photon emission-computed tomography (SPECT-CT) is not recognized. Herein, we discuss the incremental role of seldom considered SPECT-CT in early detection, leading to timely appropriate management and graft salvage in a case of posttransplant deteriorating renal allograft as a result of subcapsular hematoma.

An 89-year-old man undergoing fluorine-18 fluorodeoxyglucose positron emission tomography/ computed tomography (¹⁸F-FDG PET/CT) study posttherapy for hepatocellular carcinoma was noted to have ¹⁸F-FDG posterior layering of the urinary bladder. This phenomenon of posterior layering of ¹⁸F-FDG in the urinary bladder during PET/CT studies is physiological, and it is important to recognize to avoid misinterpretation and unnecessary investigations. The hypotheses for the cause of this phenomenon are highlighted in these interesting images including the reversed phenomenon where there is anterior layering of ¹⁸F-FDG.

We present here a case of primitive neuroectodermal tumor (PNET) who initially presented with involvement of the right 3^rd rib and underwent neoadjuvant chemotherapy, rib excision, and adjuvant chemoradiotherapy and later underwent posterolateral thoracotomy, pleural nodule excision, and the right 11^th rib metastatic lesion excision. Follow-up ¹⁸F-FDG PET/CT/computed tomography revealed unilateral brown fat suppression in the form of decreased metabolic uptake in the ipsilateral cervical, axillary, and paravertebral brown fat as compared to metabolically active contralateral brown fat, likely due to paravertebral sympathetic chain damage.

A 37-year-old man who presented with one year history of lower back and right buttock pain was investigated with contrast enhanced computed tomography (CT), magnetic resonance imaging (MRI), and fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography which revealed a diagnosis of primary fibroblastic osteosarcoma of the lumbar vertebra. This case highlights the importance of PET/CT imaging.

Vertebral hemangioma is a benign condition, but sometimes, it might represent as diagnostic dilemma especially in elderly patient mimicking serious pathology like metastasis. We report a case of a 66-year-old man with prostate cancer. 18F-sodium fluoride positron emission tomography-computed tomography (¹⁸F-NaF PET-CT) demonstrates increased radiotracer uptake at body of D4 vertebra. Magnetic resonance imaging shows features of atypical hemangioma; however, metastasis cannot be ruled out. To rule out bone metastasis, gallium-68-prostate-specific membrane antigen PET-CT is performed which shows no abnormal lesion. Eight-month follow-up by ¹⁸F-NaF PET-CT showed persistent osteoblastic lesion at D4 without any significant change thus, confirming the initial diagnosis of atypical hemangioma.

Limbic encephalitis is an autoimmune disorder characterized by inflammation of the brain with rapidly progressing dementia which requires definitive neurological evaluation. We describe both clinical as well as imaging findings in a case of limbic encephalitis using positron emission tomography/magnetic resonance imaging.

Os trigonum is a congenital condition in which a bone ossicle fails to fuse to a secondary ossification center in the posterior aspect of the talar bone. Repetitive plantar flexion of the foot may elicit inflammation of the ossicles fibrous connective band, subsequently causing pain. It is common to misdiagnose os trigonum as an avulsion fracture. We report a case of a 23-year-old male with symptomatic os trigonum diagnosed on Tc-99m hydroxymethylene diphosphonate single-photon emission computed tomography-computed tomography (SPECT-CT). We also wish to emphasize on the use of SPECT/CT in not only allocating the ossicle anatomically but also for the purpose of evaluation an active source of pain in a region of multiple complex small bones.

Pancreatic incidentalomas are increasingly recognized entities that occur as a fallout of widespread availability of high definition imaging technology. These lesions offer diagnostic dilemmas to both clinicians and radiologists alike. Nevertheless, it is the advancement in diagnostic radiology that comes to the rescue in the management of these not-so-uncommon lesions.