Evaluation of skull bone viability and effect of early surgical intervention in electrical contact burns using 18 F-Sodium Fluoride PET-CT imaging.

OBJECTIVE: Electrical contact burns of the scalp cause serious morbidity and mortality. Early necrotic bone debridement and flap cover are crucial for successful wound closure. 18 F Sodium Fluoride (NaF), with high bone-to-soft tissue activity ratio, is useful for bone viability assessment. This study evaluated the role of 18 F NaF PET-computed tomography (CT) in objectively defining the extent and depth of nonviable calvarial bone, to guide adequate bone debridement. METHOD: Of 20 patients referred to our institute with electrical contact burns of the scalp during a 2-year period, 15 were enrolled in the study. Two weeks after the initial management, tracer uptake pattern was noted on 18 F NaF PET-CT of the head and exposed bone measured. Surgical bone debridement was based on scan findings, followed by wound closure. All patients underwent clinical evaluation and follow-up scan 3 months after surgery. RESULTS: Eight patients showed a central photopenic area in the exposed bone (maximum standardized uptake value [SUVmax] of 0.76 ± 0.14 with mean maximum dimensions 4.10 ± 1.76/2.67 ± 1.54 cm). High tracer uptake (SUVmax, 9.66 ± 6.03) was seen peripheral to the exposed bone (mean maximum dimensions, 8.14 ± 3.03/4.75 ± 1.61 cm). Postoperatively, there was no significant change in tracer uptake in the central debrided region or peri-debridement bone area under the flap. Clinically all patients showed a well-healed flap. CONCLUSION: 18 F NaF PET-CT appears useful for objective evaluation of skull bone viability and planning necrotic bone debridement in patients with electrical contact burns. However, additional studies with longer patient follow-up are required to validate these results.

The Role of Trans Oral Robotic Surgery in the Carcinoma of Unknown Primary: A New Evidence in the Horizon?

The detection of the primary site in Carcinoma of Unknown Primary (CUP) is a challenging task which can significantly alter the course of management and also prognosis. Various modalities have been assessed with varying sensitivity and specificity. Imaging and cytological diagnosis have formed a key part of the diagnostic algorithm of CUP. Trans Oral Robotic Surgery offers the advantage of being both diagnostic as well as therapeutic with promising sensitivity and specificity and can form an integral part in the management of CUP. A prospective study was carried out at a tertiary care centre over a period of one year. Patients with unilateral neck swelling which was histopathologically proven squamous cell carcinoma neck metastasis were included in the study. They were evaluated with endoscopy and radiology according to the standard algorithm. When these failed to detect the primary, the patients underwent ipsilateral radical tonsillectomy and tongue base mucosal wedge biopsy via TORS. Post-operative histopathological examination was done on the resected specimens to detect the primary site. Transoral Robotic Surgery was able to localise primary in 50% of the patients enrolled in the study. Out of the primary site identified by TORS; 55.56% were located in the tonsil and 44.4% in the tongue base. TORS can offer promising detection rates of the occult primary in CUP and should form an integral part of the diagnostic algorithm.

Efficacy of Yttrium-90 Transarterial Radioembolisation in Advanced Hepatocellular Carcinoma: An Experience With Hybrid Angio-Computed Tomography and Glass Microspheres.

Background: Hepatocellular carcinoma is one of the most common malignancies worldwide. Transarterial radioembolisation (TARE) involves selective intra-arterial administration of microspheres loaded with a radioactive compound like Yttrium-90 (Y-90). Conventionally, C-arm-based cone-beam computed tomography has been extensively used during TARE. However, angio-computed tomography (CT) is a relatively new modality which combines the advantages of both fluoroscopy and fCT. There is scarce literature detailing the use of angio-CT in Y90 TARE. Methods: This was a retrospective study of primary liver cancer cases in which the TARE procedure was done from November 2017 to December 2021. Glass-based Y-90 microspheres were used in all these cases. All the cases were performed in the hybrid angio-CT suite. A single photon emission computed tomography-computed comography (SPECT-CT) done postplanning session determined the lung shunt fraction and confirmed the accurate targeting of the lesion. Postdrug delivery, positron emission tomography-computed tomography (PET-CT) was obtained to confirm the distribution of the Y-90 particles. The technical success, median follow-up, objective response rate (ORR), progression-free survival (PFS), and overall survival (OS) were recorded. Results: A total of 56 hepatocellular carcinoma patients underwent TARE during this period, out of which 36 patients (30 males and 6 females) underwent Y90 TARE. The aetiology of cirrhosis included non-alcoholic steatohepatitis (NASH) (11), hepatitis C (HCV) (11), hepatitis B (HBV) (9), metabolic dysfunction and alcohol-associated liver disease (MetALD) (2), alcoholic liver disease (ALD) (1), cryptogenic (1), and autoimmune hepatitis (AIH) (1). The technical success was 100 % and the median follow-up was 7 months (range: 1-32 months). The median OS was 15 months (range 10.73-19.27 months; 95 % CI) and the median local PFS was 4 months (range 3.03-4.97 months; 95 % CI). The ORR (best response, CR + PR) was 58 %. No major complications were seen in this study. Conclusion: TARE is a viable option for liver cancer in all stages, but more so in the advanced stages. The use of angio-CT in TARE aids in the precise delivery of the particles to the tumour and avoids non-target embolisation.

CA19-9 and CEA biosensors in pancreatic cancer.

Cancer is a complex pathophysiological condition causing millions of deaths each year. Early diagnosis is essential especially for pancreatic cancer. Existing diagnostic tools rely on circulating biomarkers such as Carbohydrate Antigen 19-9 (CA19-9) and Carcinoembryonic Antigen (CEA). Unfortunately, these markers are nonspecific and may be increased in a variety of disorders. Accordingly, diagnosis of pancreatic cancer generally involves more invasive approaches such as biopsy as well as imaging studies. Recent advances in biosensor technology have allowed the development of precise diagnostic tools having enhanced analytical sensitivity and specificity. Herein we examine these advances in the detection of cancer in general and in pancreatic cancer specifically. Furthermore, we highlight novel technologies in the measurement of CA19-9 and CEA and explore their future application in the early detection of pancreatic cancer.

Autonomous growth hormone secretion due to McCune Albright syndrome in paediatric age group: an ominous triad.

PURPOSE: The current study aimed to report cases of McCune Albright syndrome (MAS) with growth hormone (GH) hyper secretion along with a systematic review of literature to elucidate challenges and intricacies in its diagnosis and management. METHODS: It was a single centre study carried out in individuals with MAS and autonomous GH secretion (AGHS). In addition, a systematic search of literature across three databases (PubMed, Scopus and EMBASE) was performed from inception until May 31, 2021 to identify cases of MAS with AGHS in the pediatric age group (<18 years). RESULTS: Three cases from authors centre and 42 cases identified from systematic literature review were analysed. Precocious puberty was the most common presenting endocrinopathy seen in 56.8% (25/44) cases, followed by hyperthyroidism (10/45), hypophosphatemia (4/45), and hypercortisolism (2/45). Cranio-facial fibrous dysplasia (CFFD) was seen in all while polyostotic fibrous dysplasia and Café au lait macule was seen in 40/45 (88.9%) and 35/45 (77.8%), respectively. Pituitary adenoma (58.3% microadenoma) was localized in 53.3% (24/45) cases on pituitary imaging. Biochemical and clinical remission of AGHS was achieved in 61.5% (24/45) cases with medical therapy. CONCLUSION: Diagnosing AGHS in MAS is challenging because of concomitant presence of CFFD, non-GH endocrinopathies associated height spurt and elevated serum IGF-1. GH-GTT should be performed in presence of elevated growth velocity and serum IGF-1 (>1 X ULN) despite adequate control of non-GH endocrinopathies. Medical management can lead to disease control in substantial number of cases and often entails use of multiple agents.

Two-dimensional Shear Wave Elastography: Utility in Differentiating Gallbladder Cancer From Chronic Cholecystitis.

OBJECTIVE: To study the utility of 2D shear wave elastography (SWE) and ascertain cut-off values of shear wave elasticity (SWe) to differentiate benign and malignant thickening of the gallbladder wall. METHODS: This study was a prospective study of patients with symptomatic gallstone disease (GSD, n = 51) and gallbladder cancer (GBC, n = 46) and controls without any biliary disease (n = 46). All the participants underwent 2D USG and SWE of the gallbladder. Grey-scale ultrasound and SWE were done in the different regions in the gallbladder. RESULTS: The median age of the patients with GSD was 49 years (interquartile range [IQR]: 33-55), GBC was 55 years (IQR: 46-65), and controls was 37 years (IQR: 27-48.25). In patients with GBC, asymmetrical mural thickening was the predominant imaging pattern (n = 24, 52.2%). The mean SWe of the abnormal area in GBC (34.99 ± 17.77 kPa [n = 46]) was significantly higher than that of the uninvolved region (18.27 ± 8.12 kPa [n = 35]; P < .01). The mean SWe of the uninvolved region in GBC (18.27 ± 8.12 kPa [n = 35]) was also significantly higher (P < .01) than that of GSD (12.27 ± 4.13 kPa [n = 51]) and controls (10.52 ± 3.75 kPa [n = 46]). On ROC analysis, AUC of 0.927, at a cut-off of 20 kPa, sensitivity was 91.3%, specificity was 83.5%, positive likelihood ratio was 5.54, and negative likelihood ratio was 0.10 to diagnose GBC. CONCLUSION: The 2D SWE is a reliable adjunctive tool to grey-scale USG in differentiating the malignant from benign gallbladder wall and may help to pick up early malignancy in GSD.

Applicability of Adults 2015 American Thyroid Association Differentiated Thyroid Cancer Guidelines for Postoperative Risk Stratification and Postradioiodine Treatment Dynamic Risk Stratification in Pediatric Population.

Purpose This retrospective study aimed to study the applicability of 2015 adult American Thyroid Association (ATA) differentiated thyroid cancer (DTC) postoperative risk stratification and guidelines in the pediatric population for evaluating the number of metastatic lymph nodes in the postoperative risk stratification and postradioactive iodine (RAI) treatment dynamic risk stratification (DRS) using response to treatment (RTT) reclassification. In addition, the effect of pubertal status and gender was assessed on disease presentation and prognosis. Methods Data of 63 DTC patients aged 20 years or less, stratified into prepubertal, pubertal, and postpubertal age groups, was divided into low, intermediate, and high-risk groups using pediatric ATA recurrence risk stratification. Forty-seven patients were classified as responders (excellent and indeterminate responses) and incomplete responders (biochemical and structurally incomplete responses) by assessing the RTT at 1.5 years follow-up similar to recommendation of 2015 adult DTC ATA guidelines. Results Female-to-male ratio showed a trend of gradual increase with increasing age. Significantly more responders were observed in low- and intermediate-risk groups than in high-risk group ( p = 0.0013; p = 0.017, respectively), while prepubertal group had more extensive (N1b) disease. Using DRS at follow-up of 1.5 year, pubertal and postpubertal groups showed significantly better response to RAI. More female than male patients showed response and took significantly less time to respond to RAI ( p = 0.003). Conclusion RAI response in pediatric DTC depends on pubertal status, gender, and number of malignant nodes. DRS using RTT classification may be applicable early at 1.5 years after initial therapy in different pubertal age and risk groups.

[68 Ga]Ga-PSMA-11 Small Bowel Uptake in Crohn's Disease: Revisiting the "Non-specificity" of PSMA Ligands.

The rapidly evolving clinical utility of prostate-specific membrane antigen (PSMA) PET/CT as an imaging modality for prostate cancer (PCa) has brought to the forefront a multitude of non-prostatic diseases also exhibiting PSMA radioligand uptake. We report a case of a 71-year-old male with PCa who underwent PSMA PET/CT for recurrence evaluation. The scan demonstrated [68 Ga]Ga-PSMA-11 uptake in the distal ileum. Retrospective enquiry revealed that the patient was a known case of Crohn's disease. This case highlights an uncommon finding of PSMA radioligand uptake in the distal small bowel (non-prostatic benign pathological uptake) in a patient with known Crohn's disease, which may be misinterpreted in the evaluation of PCa.

Bilaterally ectopic pelvic kidneys masquerading as horseshoe kidney in Fanconi anemia.

Fanconi anemia (FA) is a genetic disease associated with the risk of different congenital malformations, bone marrow failure, and predisposition to cancer. Congenital abnormalities of the kidney and urinary tract are not infrequent in FA with renal ectopia being one of them. The incidence of the bilateral pelvic ectopic kidney is restricted to only a few reported cases; however, its association with FA has never been reported in the literature. We present a case of Fanconi anemia in a young girl with apparently fused kidneys on a 99mTc-DMSA planar scan which was confirmed to be bilateral pelvic kidneys on hybrid cross-sectional imaging.

Safety and Diagnostic Yield of 68Ga Prostate-specific Membrane Antigen PET/CT-guided Robotic-assisted Transgluteal Prostatic Biopsy.

Background Transrectal US-guided biopsy with or without MRI fusion is performed for diagnosing prostate cancer (PCa) but has limitations. Gallium 68 (68Ga) prostate-specific membrane antigen (PSMA) PET/CT-guided targeted biopsy has the potential to improve diagnostic yield of PCa. Purpose To evaluate the safety and diagnostic yield of 68Ga PSMA PET/CT-guided, robotic-arm assisted transgluteal prostatic biopsy. Materials and Methods In this single-center nonrandomized prospective trial, participants with a clinical suspicion of PCa (serum prostate-specific antigen level > 4 ng/mL) were recruited from January 2019 to September 2020. After whole-body 68Ga PSMA PET/CT, participants with PSMA-avid intraprostatic lesions underwent PET-guided transgluteal biopsy by using an automated robotic arm. To assess safety and diagnostic yield, procedure-related complications and histopathologic results were documented. Pain during the procedure was scored by a visual analog scale. Descriptive statistics were applied; qualitative variables were reported in percentages. Results Seventy-eight participants (mean age, 66 years ± 7 [standard deviation]; 36 participants [46%] with prior negative results at transrectal US-guided biopsy) were enrolled. Fifty-six (72%) participants had PSMA-avid lesions (prior negative results at transrectal US-guided biopsy in 22 of 56 [39%]) and underwent targeted biopsy. PCa was confirmed in 54 of 56 (96%) participants, and clinically significant PCa (Gleason score ≥ 7) was confirmed in 24 of 54 (44%). Two participants had nonrepresentative samples that required rebiopsy. All participants experienced pain during the procedure, mild (median visual analog scale score, 1; interquartile range, 1-2) in 36 of 56 (64%) and moderate (median visual analog scale score, 5; interquartile range, 5-6) in 20 of 56 (36%). Postprocedure complications were noted in five of 56 (9%) participants and were minor (hematuria, four participants; hematospermia, one participant; and gluteal pain, two participants). No participant developed a postprocedural infection. Conclusion Transgluteal prostate-specific membrane antigen (PSMA) PET/CT-guided, robotic-targeted prostatic biopsy is safe with a high diagnostic yield of prostate cancer for PSMA-avid lesions. Clinical trial registration no. NCT05022576 © RSNA, 2022.

Toxic thyroid adenoma with hypercalcemia mimicking an intra-thyroidal parathyroid adenoma.

Hypercalcemia is a clinical condition characterized by elevated circulating serum calcium levels either due to raised parathyroid hormone in hyperparathyroidism or due to secondary causes of hypercalcemia without elevated parathyroid hormone levels. However, hyperthyroidism may occasionally present with incidentally detected hypercalcemia. We present a case of a 53-year-old woman with a previous history of an underlying thyroid disorder, now presented with features of hypercalcemia and mildly elevated parathyroid hormone levels. Her ultrasonography of the neck was suggestive of an intra-thyroidal parathyroid adenoma and it was localized as a tracer avid lesion within the thyroid gland on dual-phase 99mTc-sestamibi planar scintigraphy with single photon emission computed tomography/ computed tomography (SPECT/CT). However, a subsequent thyroid profile followed by 99mTc- pertechnetate thyroid scintigraphy showed a hot nodule in the thyroid gland which changed the diagnosis to a toxic thyroid adenoma. She was treated with radioactive iodine ablation and thyrotoxicosis resolved and the serum calcium levels normalized on her follow-up.

Hematological Markers as Predictors of Treatment Outcomes with Lutetium 177 (177Lu)-DOTATATE in Patients with Advanced Neuroendocrine Tumors.

Background: Chronic inflammation has been linked to the development and prognosis of neuroendocrine tumors (NETs). The current study intended to evaluate the role of peripheral hematological inflammatory markers, viz. the platelet-lymphocyte ratio (PLR), neutrophil-lymphocyte ratio, and monocyte-lymphocyte ratio, as predictors of treatment outcomes in patients with advanced NETs after Lutetium-177(177Lu)-DOTATATE therapy. Materials and Methods: Data of consecutive patients with advanced metastatic and/or inoperable NETs treated with 177Lu-DOTATATE from the year 2012 to 2019 at the authors' center were retrospectively analyzed. Results: Forty-two NET patients (median age: 49.5 years) received a median cumulative activity of 29.6 GBq of 177Lu-DOTATATE over 2-5 cycles at 8-12-week intervals. The median progression-free survival (PFS) of the study cohort was 30 months (95% confidence interval, CI: 18.2-41.9 months). A baseline PLR ≥173.1 was found to be a significant predictor of poor PFS with a univariate hazard ratio of 3.82 (95% CI: 1.21-12.03); however, the association was not significant on multivariate analysis. The median overall survival was not reached and none of the parameters were significantly associated with it. Conclusions: A higher baseline PLR was shown to be associated with a negative outcome on PFS after 177Lu-DOTATATE therapy and is a promising marker for future larger studies.

Versatile Role of 18F-FDG PET/CT in a Patient with Pan-cerebellar Paraneoplastic Manifestation Due to Underlying Hodgkin's Lymphoma.

Hodgkin's lymphoma most commonly presents as painless lymphadenopathy and systemic B symptoms like fever, night sweats, and weight loss. But rarely, it can present with unusual paraneoplastic manifestations. In the present case, we report a 30-year-old woman who presented with sub-acute onset pan-cerebellar symptoms. The serum neuronal antibody panel was negative. She underwent F-18 FDG PET/CT to evaluate the neoplastic etiology as the underlying cause, which demonstrated both the primary etiology and the paraneoplastic changes in the brain.

Early Quantification of Salivary Gland Function after Radioiodine Therapy.

PURPOSE OF THE STUDY: Radioiodine (I-131) is used as an effective noninvasive treatment for thyroid malignancies. Salivary gland is one of the most affected nontarget organs. The present study aims to perform early quantification of salivary gland function after I-131 therapy (RIT) for thyroid cancer considering I-131 down-scatter in the Tc-99m window. MATERIALS AND METHODS: A total of 20 patients (6 males and 14 females) with differentiated thyroid carcinoma were enrolled in the study. Baseline dynamic salivary scintigraphy was performed in all patients using 185-370 MBq (5-10 mCi) Tc-99m pertechnetate. Posttherapy, salivary scintigraphy was performed 10-25 days after RIT in the range of 1.85-7.4 GBq (50-200 mCi). Time-activity curves obtained from the pre- and posttherapy dynamic salivary scintigraphy were used for semi-quantitative analysis. Uptake ratio (UR), ejection fraction (EF%), and maximum accumulation (MA%) were calculated by drawing regions of interest of individual parotid and submandibular glands over a composite image, after correcting for down-scatter from I-131 in the Tc-99m window. A paired t-test was used for comparison of the parameters obtained. RESULTS: Significant changes were observed in UR and EF% of both parotid and submandibular glands (P < 0.05). No significant changes were found in the value of MA% of left parotid gland and both submandibular glands in the posttherapy scans in comparison to pretherapy scans (P > 0.05). However, significant difference was observed in the MA% of the right parotid gland (P = 0.025). CONCLUSION: Salivary gland function was found to deteriorate after RIT, with the parotid glands affected more than the submandibular glands.

Posttraumatic Scab on 131I Whole-Body Scan-A False-Positive Finding.

ABSTRACT: 131I scan plays a crucial role in the management of patients with differentiated thyroid cancer for the evaluation of remnant thyroid tissue, residual/recurrent metastatic disease, posttherapy tracer distribution, and response assessment to high-dose 131I therapy. Different causes secondary to physiological, pathological, and anatomical variations have been described for false-positive findings in the whole-body planar images. This case report of a patient of differentiated thyroid cancer with undocumented trauma to the left knee region a day before receiving the high-dose radioiodine therapy showed an interesting image finding of tracer uptake at unusual site in the posttherapy whole-body 131I scan.

Can Sentinel Lymph Node Biopsy Predict Various Levels of Echelon Nodes in Oral Cancers?

Abstract Introduction The efficacy of sentinel node biopsy in early stage oral cancer is well established. Its evolving role can be reinforced by further studies. Objective Analyzing the predictability of the levels of echelon nodes for various oral cavity tumor subsites on sentinel node biopsy. Methods A prospective study of 20 patients with stage I/II oral squamous cell carcinoma who underwent sentinel node biopsy-guided neck dissection between January 2017 and 2018 at our institute. The procedure included radiotracer injection, imaging (lymphoscintigraphy, single photon emission computed tomography-computed tomography), and gamma probe application. Sentinel node detection on imaging and gamma probe were compared. Results Out of 20 patients, 13 (65%) had carcinoma of the tongue, 6 (30%) had buccal mucosa carcinoma, and 1 (5%) had retromolar trigone carcinoma. Themean age of the patients was 52.3 years. A total of 13 (65%) patients were male, and 7 (35%) were female. The sentinel node identification rates with imaging and gamma probe were of 70% and 100% respectively. In tongue and retromolar trigone primaries, the most common first-echelon nodes in both modalities were levels IIA and IB respectively. For buccal mucosa primaries, first-echelon nodes were detected only with the gamma probe, which was level IB. On imaging, second-echelon nodes were detected only for tongue primaries, and had equivalent incidence of levels II, III, and IV. On the gamma probe, level IIA, followed by III, and IV for the tongue, and level IIA were the most common second-echelon nodes for the buccal mucosa. Third-echelon nodes were detected only with the gamma probe for tongue carcinoma at level IV. Conclusion The combined use of imaging and gamma probe provides the best results, with high identification rate and predictability of echelon levels.

Can Sentinel Lymph Node Biopsy Predict Various Levels of Echelon Nodes in Oral Cancers?

Introduction The efficacy of sentinel node biopsy in early stage oral cancer is well established. Its evolving role can be reinforced by further studies. Objective Analyzing the predictability of the levels of echelon nodes for various oral cavity tumor subsites on sentinel node biopsy. Methods A prospective study of 20 patients with stage I/II oral squamous cell carcinoma who underwent sentinel node biopsy-guided neck dissection between January 2017 and 2018 at our institute. The procedure included radiotracer injection, imaging (lymphoscintigraphy, single photon emission computed tomography-computed tomography), and gamma probe application. Sentinel node detection on imaging and gamma probe were compared. Results Out of 20 patients, 13 (65%) had carcinoma of the tongue, 6 (30%) had buccal mucosa carcinoma, and 1 (5%) had retromolar trigone carcinoma. The mean age of the patients was 52.3 years. A total of 13 (65%) patients were male, and 7 (35%) were female. The sentinel node identification rates with imaging and gamma probe were of 70% and 100% respectively. In tongue and retromolar trigone primaries, the most common first-echelon nodes in both modalities were levels IIA and IB respectively. For buccal mucosa primaries, first-echelon nodes were detected only with the gamma probe, which was level IB. On imaging, second-echelon nodes were detected only for tongue primaries, and had equivalent incidence of levels II, III, and IV. On the gamma probe, level IIA, followed by III, and IV for the tongue, and level IIA were the most common second-echelon nodes for the buccal mucosa. Third-echelon nodes were detected only with the gamma probe for tongue carcinoma at level IV. Conclusion The combined use of imaging and gamma probe provides the best results, with high identification rate and predictability of echelon levels.

68Ga-DOTA-RGD2 Positron Emission Tomography/Computed Tomography in Radioiodine Refractory Thyroid Cancer: Prospective Comparison of Diagnostic Accuracy with 18F-FDG Positron Emission Tomography/Computed Tomography and Evaluation Toward Potential Theranostics.

Background: Radioiodine therapy (131I) forms a principal cornerstone in the management of differentiated thyroid cancer. Radioiodine-refractory differentiated thyroid cancer (RAIR-DTC) presents a challenge in detection of structural disease in patients with evidence of biochemical disease and in treatment of the disease using alternate therapies. The present study was conducted to compare the diagnostic accuracy (in terms of sensitivity and specificity) of 68Ga-DOTA-RGD2 positron emission tomography (PET)/computed tomography (CT) as a neoangiogenesis imaging modality with 18F-FDG PET/CT, the current standard in diagnostic algorithm of RAIR-DTC, and to evaluate the radiotracer avidity on 68Ga-DOTA-RGD2 PET/CT for potential theranostics. Methods: Forty-four RAIR-DTC patients with negative post-therapy 131I scan were prospectively enrolled. Serum thyroglobulin (sTg) and anti-thyroglobulin (ATg) measurements were performed with levothyroxine withdrawal (thyrotropin-stimulated state), and 18F-FDG PET/CT and 68Ga-DOTA-RGD2 PET/CT studies were performed within 1 week of each other. Follow-up was performed with histopathology/sTg/ATg/conventional imaging. The findings of 18F-FDG PET/CT and 68Ga-DOTA-RGD2 PET/CT were compared with the reference standard to obtain sensitivity, specificity, and overall accuracy. Degree of radiotracer uptake on 68Ga-DOTA-RGD2 PET/CT was described as tumor to background (T/B) and tumor to liver (T/L) ratios of standardized uptake value. Results:68Ga-DOTA-RGD2 PET/CT detected a total of 123 lesions, with an overall sensitivity, specificity, and accuracy of 82.3%, 100%, and 86.4%, respectively. 18F-FDG PET/CT detected a total of 144 lesions, with an overall sensitivity, specificity, and accuracy of 82.3%, 50%, and 75%, respectively. Most commonly identified disease sites were nodal metastases (82.9%), followed by thyroid bed lesions (10.5%). 82.1% of patients positive on 68Ga-DOTA-RGD2 PET/CT showed lesional radiotracer uptake higher than the liver (grade IV and grade V). Conclusions:68Ga-DOTA-RGD2 PET/CT showed a similar sensitivity to, but higher specificity and overall accuracy than 18F-FDG PET/CT in detection of lesions in RAIR-DTC patients. This novel application of the angiogenesis imaging modality can prove useful in RAIR-DTC, especially in patients with negative/suspicious 18F-FDG PET/CT. Furthermore, since the majority of patients (82.1%) positive on 68Ga-DOTA-RGD2 PET/CT showed radiotracer avidity toward the higher end of the spectrum (grade IV and grade V), novel 177Lu-based theranostics can be a potential treatment for these patients.

Isolated Involvement of Prostate Gland by Immunoglobulin G4-Related Disease Diagnosed With the Help of FDG PET/CT.

Immunoglobulin G4 (IgG4)-related disease is known to mimic multiple malignancies and always poses a diagnostic challenge. We report a case of a 20-year-old young man, who presented with unexplained recurrent episodes of fever and pain abdomen. F-FDG PET/CT revealed intense focal FDG avidity in the prostate. On further workup, he had an elevated serum IgG4 level, and a clinical diagnosis of immunoglobulin G4-related disease was kept. A follow-up FDG PET/CT after glucocorticoid therapy revealed resolution of FDG avidity in the prostate with fall in serum IgG4 levels, hence confirming a diagnosis of atypical immunoglobulin G4-related disease involving isolated prostate gland.

Role of 18F-fluorodeoxyglucose positron emission tomography/computed tomography in restaging and prognosis of recurrent melanoma after curative surgery.

Malignant melanoma is a highly aggressive tumor and surgical resection is the primary treatment. However, the chances of recurrence are quite high despite complete resection. The aim of study was to evaluate the 18F-fluorodeoxyglucose(18F-FDG) positron emission tomography-computed tomography (PET/CT) in detection of recurrent melanoma after curative surgery and its prognostic value. Fifty-four melanoma patients (32 women) with prior primary lesion resection were evaluated with 18F-FDG PET/CT for clinically suspicious recurrent disease. The diagnostic accuracy of 18F-FDG PET/CT (visual interpretation as well as semi-quantitative parameter) was determined on the basis of subsequent imaging and clinical follow-up. Melanoma-specific survival and risk of progression (hazard ratio [HR]) were assessed using Kaplan-Meier method and Cox regression analysis. 18F-FDG PET/CT detected recurrent diseases in 36 (66%) patients including distant metastases in 13 patients and second synchronous malignancy in 2 patients. Overall, the sensitivity, specificity, positive predictive value, and negative predictive value of 18F-FDG PET/CT were 91.2%, 80.0%, 88.6%, and 84.2%, respectively, with area under the curve of 0.86 (95% confidence interval: 0.74-0.97; P < 0.05). Positive 18F-FDG PET/CT study was associated with a significantly shorter overall survival than negative study (30.8 ± 4.6 vs. 64.5 ± 6.9 months, P < 0.05). Apart from positive 18F-FDG PET/CT scan, maximum standardized uptake value (SUVmax) >2.7 and combination of both were independently associated with an increased risk of disease progression (HR = 7.72, 21.58, and 11.37, respectively; P < 0.05). 18F-FDG PET/CT showed enhanced diagnostic performance in patients with suspicious recurrent malignant melanoma leading to appropriate management. FDG positivity along with SUVmax >2.7 provides important prognostic value in predicting the survival outcomes and assessing the risk of disease progression.