[18F]FDG PET/CT in Benign and Malignant Diseases Involving the Biliary Tract.

Role of FDG PET/CT in evaluation of biliary tract diseases remains relatively unexplored. PET/CT with FDG helps in evaluation of both infective / inflammatory as well as neoplastic diseases as increased glucose utilization is observed in both the conditions. In this article, we describe the spectrum of FDG PET/CT findings in various diseases affecting the biliary tract. Role of FDG PET/CT in neoplastic diseases involving the biliary duct has been described at the time of staging and response evaluation; in characterization of the intrahepatic mass (abscess v/s cholangiocarcinoma). In addition, we have discussed about the false positive FDG uptake along the biliary duct stent, which interfere with scan interpretation. Few of the benign conditions described are Langerhans cell histiocytosis and IgG4 related disease involving the biliary duct and adenomyomatosis and Xanthogranulomatous cholecystitis involving the gall bladder.

Detection and Response Evaluation of Extramedullary and Medullary Blast Crisis in Chronic Myeloid Leukemia on 18F-FDG PET/CT.

ABSTRACT: FDG PET/CT imaging is usually not routinely undertaken in patients of chronic myeloid leukemia (CML). We present a case of CML on tyrosine kinase inhibitor treatment with disease control indicated by BCR-ABL1 quantitative reverse transcription-polymerase chain reaction, who underwent PET/CT for evaluation of recent onset vision deterioration with subretinal exudates on ophthalmological examination. PET CT detected FDG-avid sinonasal thickening and bilateral marrow lesions. These lesions on histopathological sampling, examination revealed extramedullary and intramedullary CML blast crisis. Patient was then treated with steroids and change of tyrosine kinase inhibitor for the CML blast crisis. FDG PET/CT done subsequently was able to demonstrate morphological and metabolic response in the lesions.

18F-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography in a Rare Case of Epithelioid Hemangioendothelioma - A Diagnostic Challenge.

Our case highlights the 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) scan findings in a rare case of biopsy-proven epithelioid hemangioendothelioma (EHE) in a 66-year-old woman with multi-organ involvement (lung, liver, and bone) who was subsequently treated with palliative radiation therapy and oral pazopanib. Furthermore, follow-up 18F-FDG PET/CT findings are detailed. EHE is a rare malignant vascular neoplasm (<1% of all vascular tumors) with an epithelioid and histiocytoid appearance arising from the vascular endothelial and preendothelial cells.

Cytological Diagnosis of Castleman Disease by Endoscopic Ultrasound Guided Fine Needle Aspiration.

Castleman disease is a nonmalignant, lymphoproliferative disorder. Unicentric disease type involves a single enlarged lymph node or nodal regions, and multicentric disease involves multiple lymph node site involvement. We present a case of 26-year-old young female presented to outpatient with complaint of generalized weakness and abdominal pain for last 2 months. Her imaging included positron emission computed tomography which showed soft-tissue mass along the body of pancreas. Endoscopic ultrasound done showed nodal mass with extensive calcification and doppler endoscopic ultrasound showing arborising vessels. Fine needle aspiration cytology (FNAC) and biopsy taken showed lymphoid cells and diffuse hyaline material. After suboptimal response to chemotherapy regimen, she underwent open laparotomy and excision of the retroperitoneal mass.

Ga-68 Prostate-Specific Membrane Antigen-HBED-CC Positron Emission Tomography/Computed Tomography in Anaplastic Thyroid Carcinoma.

Purpose: Anaplastic thyroid carcinoma (ATC) is the most aggressive thyroid cancer and there is no established treatment that works well. The study was conducted to see prostate-specific membrane antigen (PSMA) expression in ATC as a stepping stone to study its role in potential theranostics. Materials and Methods: Pathologically proven ATC patients were prospectively included in this study. Ga-68-PSMA positron emission tomography/computed tomography (PET/CT) was done to look for PSMA expression in local and distant sites 45-60 mins after injecting 2-3mCi of tracer. Results: Twenty patients were enrolled in this study. Nodal metastases were seen in all patients, while distant metastases were seen in 17/20. The mean SUVmax of primary lesion was 6.72 ± 4.6. Mean SUVmax of node and lung lesions was 5.7 ± 5.6 and 2.9 ± 1.98, respectively. Mean SUVmax of liver, mediastinum, and parotid gland was 5.95 ± 3.03, 1.54 ± 0.68, and 9.03 ± 3.75, respectively. Mean Tumor to background ratio (liver = TBRl; mediastinum = TBRm; parotid = TBRp) were 1.21, 4.49 and 0.78, respectively. Conclusion: ATC showed variable PSMA expression on Ga-68-PSMA-PET/CT and this attribute may be potentially useful in ATC theranostics.

It's the data, stupid: Inflection point for Artificial Intelligence in Indian healthcare.

Indian healthcare is fast growing and with significant chunk of it being in small, fragmented, informal sector; Artificial Intelligence (AI) is pegged as a magical tool for a better healthcare system. There is an inclination to merely mimic the US approach in the on-going policy making and legislative exercises, which can have serious fallouts for Indian healthcare. India needs a different approach to suite her unique requirements. In this regard, each of the five stages in AI development lifecycle has been analyzed in the light of current on-ground realities. These boil down to three fold challenges of how to increase adoption of digital health, prevent data silos and create maximum value from data. Availability of quality data for value addition without barriers and restrictions is the common denominator for leveraging the full potential of AI. This requires liberal policies enabling secondary use of data in developing countries with rapidly growing healthcare sector akin to India. This has to be carefully balanced with data privacy and security. Restrictive healthcare data policies and laws can slow down adoption of digitization, perpetuate status-quo, be biased towards the incumbent players, cause Industry stagnation and thus will do more harm than good. It is therefore the data policies that will make or break AI in Indian healthcare.

18-F Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography of a Large Inflammatory-Hepatocellular Adenoma.

We report a case of an 81-year-old male evaluated for a liver space-occupying lesion. US-guided biopsy and immunohistochemistry were suggestive of hepatocellular adenoma (HCA)-inflammatory (with telangiectasia). Serial 18-F fluorodeoxyglucose (18F-FDG) positron emission tomography/computed tomography scans revealed a heterogeneously enhancing hypermetabolic mass in the right lobe of the liver, remaining stable for a span of 3 years. This case highlights that benign rare tumors of the liver such as HCA can be intensely FDG avid and that uptake cannot conclude its malignant transformation.

Spectrum of 18F-FDG Uptake in Bilateral Lung Parenchymal Diseases on PET/CT.

Bilateral lung parenchymal involvement is seen in infective as well as noninfective conditions, appearing as focal or diffuse lung disease. PET/CT with FDG helps in characterization (increased glucose utilization is seen by both inflammatory and neoplastic cells). In this article, we describe the spectrum of patterns of FDG uptake and associated CT changes involving bilateral lung parenchyma. Benign conditions described are aspiration pneumonia; pulmonary toxicity by bleomycin; infections, namely, sarcoidosis, miliary pulmonary tuberculosis, and pulmonary nocardiosis; and inflammatory conditions such as pulmonary Langerhans cell histiocytosis and pulmonary alveolar proteinosis. Neoplastic conditions described are bilateral pulmonary metastases and lymphangitic carcinomatosis.

18F-FDG PET/CT in cyst infection in autosomal dominant polycystic kidney disease.

Infection of a cyst within an autosomal dominant polycystic kidney disease (ADPKD) is a serious complication. Diagnosis with conventional imaging techniques such as ultrasonography, computed tomography (CT), and magnetic resonance imaging can be sometimes challenging. The definite diagnosis is analysis of the cyst fluid, but cyst punctures can cause bleeding, rupture, and contamination of adjacent cysts. Recently, FDG PET/CT has been reported as a sensitive tool for detection of cyst infection. We describe a case of 63-year-old woman with infected cysts in the left kidney, in whom accurate diagnosis was made on FDG PET/CT. FDG PET/CT is an important investigation in patients with fever of uncertain etiology, where renal cyst infection is a possible cause, but other etiologies also need to be ruled out.

Long-term Clinicopathological Features of a Family with Multiple Endocrine Neoplasia Type 2A Caused by C634R RET Gene Mutation.

Type 2 multiple endocrine neoplasia (MEN2A) is a variant of hereditary medullary thyroid carcinoma (MTC). MEN2A is characterized by the presence of the following: MTC, hyperparathyroidism, and pheochromocytoma (PHEO). The pathogenesis includes RET proto-oncogene mutation; the most frequently observed mutation is in exon 11 codon 634. We report pedigree of a large Indian family involving three generations including 21 members with MEN2A, in whom RET mutation status was determined. We then analyzed their clinical follow-up details, with a median duration of follow-up of 60 months (range: 9-276 months). Calcitonin (Ctn) levels were routinely checked during the follow-up. The index case was found to carry p.C634R mutation involving exon 11 of the RET gene. RET mutation was positive in 12 members in the family (12/21, i.e., 57%), was negative in 7 patients, and was not tested in 2 patients, as they were not available for the genetic test. Thirteen were clinically affected with MTC and 10 members had PHEO. At the last follow-up, the median Ctn level was 14.3 pg/mL (range: 2-12655 pg/mL). Four patients developed lymph nodal recurrence during follow-up, for which they underwent re-operations with median duration to recurrence being 48 months (range: 9-156 months). We highlight in this article that early diagnosis, adequate surgery, and appropriate genetic counseling with genetic screening are essential to improve the outcome of persons with MTC. Every case of MTC should be seen as familial or index case of hereditary MTC unless otherwise RET mutation excludes it.

RET gene mutation analysis and long-term clinical outcomes of medullary thyroid cancer patients.

OBJECTIVE: Medullary thyroid carcinoma is a rare, potentially aggressive tumour, with relatively worse prognosis than well-differentiated thyroid cancer. We evaluated the long-term outcomes and prognosis of medullary thyroid carcinoma patients at a single institution in India and compared outcomes based on results of RET protooncogene mutation analysis. METHODS: Data were retrieved through a prospectively maintained thyroid cancer database from 1998 to June 2019, and medullary thyroid carcinoma patients were recruited. RET gene mutation status (exon 10-16) was assessed. Patient with a minimum follow-up of 12 months was eligible to be part of the long-term outcome analysis. RESULTS: Out of 149 peripheral blood samples, 42 were positive for RET gene mutation (prevalence of 28.1%). The median follow-up duration was 48 months, ranging from 12 to 240 months. Long-term clinical outcomes of 113 patients were assessed. Two deaths were noted in this series. Both 5- and 10-year survival was cent per cent. Overall survival was 98.2% (97.3% in RET positive and 98.7% in RET negative group). Progression-free survival was 55.4% in total (60% in RET positive and 53.3% in RET negative group). No statistically significant difference was found between RET positive and RET negative groups concerning overall survival (P = 0.6011) and progression-free survival (P = 0.5140). Univariate analysis revealed high calcitonin (>10 pg/mL), stage IV disease, and presence of lymph nodal metastasis to be significant predictors of disease recurrence, however, multivariate analysis demonstrated the presence of lymph node metastases as the only significant predictor of recurrence (P = 0.0005). CONCLUSIONS: Medullary thyroid carcinoma patients had relatively favourable long-term outcomes. Long-term survival was similar irrespective of RET mutation status. Presence of lymph node metastases appeared to be the strongest predictor of overall and progression-free survival, followed by Calcitonin level and stage of the disease.

Fluorocholine PET Imaging of Parathyroid Disease.

To give an overview of the potential clinical utility of 18F-fluorocholine PET/CT (FCH PET/CT) in imaging of parathyroid adenoma. Available studies have provided preliminary results of 18F-FCH PET/CT in primary and secondary hyperparathyroidism. Results of various studies have shown that 18F-FCH is a promising upcoming tracer for the detection of parathyroid adenomas, especially when multiple, or having low size. FCH PET/CT has the potential to be a standard investigation in the detection of parathyroid lesions.

Detection of Solitary Axillary Lymph Node Metastases from Hürthle Cell Carcinoma of the Thyroid on 18F-FDG PET/CT.

Thyroid carcinoma is the most common neoplasm of endocrine malignancies. Differentiated thyroid carcinoma (DTC) constitutes 90% of the thyroid carcinomas, rest being medullary thyroid carcinoma (MTC), and anaplastic thyroid carcinoma (ATC). Distant metastases occur in up to 10% of patients with DTC. Metastases to axillary lymph nodes (ALN) are very rare. As per literature, only 25 cases have been reported. We report an unusual case of 47-year-old male with Hürthle cell carcinoma of the thyroid presenting with a solitary axillary lymph node metastasis 17 years after thyroidectomy, along with review of literature.

Demonstration of 68Ga-prostate-specific Membrane Antigen Uptake in Metastatic Pancreatic Neuroendocrine Tumor.

We present the case of a 47-year-old female with metastatic pancreatic neuroendocrine tumor (NET). The patient was treated with long-acting octreotide which failed to halt disease progression. The patient was being considered for 177Lu-peptide receptor radionuclide therapy, and a 68Ga-DOTANOC positron emission tomography-computed tomography (PET-CT) was acquired initially, which showed good uptake in the primary and metastatic lesions. Metastatic pancreatic NETs have limited treatment options, and given the background that these tumors are highly vascular and prostate-specific membrane antigen (PSMA) expression is known in the endothelium of tumor neovasculature, we decided to perform a 68Ga-PSMA-HBED-CC PET-CT scan. It revealed radiotracer uptake in the metastatic liver lesions although not as high as 68Ga-DOTANOC-PET-CT. PSMA expression needs to be researched further, especially in high-grade NETs where somatostatin expression may be poor.

Prostate-specific Membrane Antigen Imaging in Recurrent Medullary Thyroid Cancer: A New Theranostic Tracer in the Offing?

Prostate-specific membrane antigen (PSMA) expression has been shown in neovasculature of various malignancies. Recurrent medullary thyroid cancer (MTC) is difficult to treat. We present the findings on PSMA-positron emission tomography/computed tomography (PET/CT) of a 68-year-old man with MTC, who presented with a recurrent left paratracheal mass and rising calcitonin. The scan revealed significant uptake on PSMA imaging but not on 68Ga-DOTANOC PET/CT. 177Lu-PRRT is one of the therapeutic options in patients with recurrent MTC, but in this case was not possible due to lack of somatostatin receptor expression. Imaging evidence of PSMA expression alerts us to the potential use of 177Lu-DKFZ-PSMA-617 therapy in such patients.

Comparability of Early Dynamic and Conventional Static Imaging With 18F-Fluorocholine PET/CT in a Patient With Primary Hyperparathyroidism.

Recent studies have established the superiority of FCH PET/CT over MIBI scan in accurate preoperative localization of parathyroid adenomas. In this patient, we compared both early dynamic and conventional static imaging to see if early imaging could suffice. We describe a 15-year-old boy with primary hyperparathyroidism, in whom early dynamic FCH PET/CT was performed for 15 minutes after injection, followed by conventional static image at 60 minutes. Early dynamic images accurately localized the parathyroid adenoma. Also, higher SUVmax was observed on dynamic imaging when compared with conventional static images, but parathyroid-to-thyroid ratio was higher in the latter.

Assessment of the role of early dynamic PET/CT with 18F-fluorocholine in detection of parathyroid lesions in patients with primary hyperparathyroidism.

OBJECTIVE: The aim of the present study was to assess the utility of early dynamic PET/computed tomography with fluorine-18-fluorocholine (F-FCH) in detecting parathyroid lesions and in differentiating parathyroid lesions from cervical lymph nodes (LNs). PATIENTS AND METHODS: A prospective study was conducted on 14 patients with clinical and biochemical evidence of primary hyperparathyroidism by having a positive Tc-sestaMIBI scan. Patients underwent early dynamic F-FCH PET/computed tomography scan, after the administration of 5-8 mCi (185-296 MBq) at 1 min per frame for 15 min. Delayed static images of 2-3 min per bed position were taken between 45 and 60 min. 3D-VOI's were plotted on parathyroid adenoma, cervical LN and thyroid. Dynamic and static images were interpreted by two expert nuclear medicine physicians independently and the following parameters were calculated for parathyroid adenoma and cervical LN: maximum standardized uptake value (SUVmax), time activity curve for SUVmax, t-peak. Adenoma to thyroid ratio (A/T) and cervical LN to thyroid ratio were calculated for each dynamic and static image. RESULTS: Fourteen (eight females and six males) patients were included in the study. All patients showed a higher SUVmax in the adenoma and the cervical LN in the early dynamic images as compared with delayed static images. A/T ratio obtained in the dynamic and static images were compared and found to have insignificant difference (P=0.2255). The difference between mean A/T and LN to thyroid ratio was found to be significant (P=0.0117) during the dynamic study. CONCLUSION: A possible explanation of higher SUVmax in the dynamic images in adenomas may be due to the increased vascularity/early F-FCH uptake. Results indicate early dynamic imaging could suffice, without the need for a delayed image after 45 min, and this technique could adequately differentiate a parathyroid adenoma from a cervical LN.

Role of Preablative Stimulated Thyroglobulin in Prediction of Nodal and Distant Metastasis on Iodine Whole-Body Scan.

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.

Role of Early Dynamic Positron Emission Tomography/Computed Tomography with 68Ga-prostate-specific Membrane Antigen-HBED-CC in Patients with Adenocarcinoma Prostate: Initial Results.

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. SUVmax was 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.