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ABSTRACT
Year : 2013  |  Volume : 28  |  Issue : 5  |  Page : 6-10  

PET- Oncology


Date of Web Publication29-Nov-2013

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How to cite this article:
. PET- Oncology. Indian J Nucl Med 2013;28, Suppl S1:6-10

How to cite this URL:
. PET- Oncology. Indian J Nucl Med [serial online] 2013 [cited 2019 Dec 14];28, Suppl S1:6-10. Available from: http://www.ijnm.in/text.asp?2013/28/5/6/122394

Pet -O-01

Comparision and correlation of 18F fluorodeoxyglucose-positron emission tomography-computed tomography, operative and histopathological findings in gall bladder cancer: An initial experience of twenty one studies

Jayanta Das, Sudeep Banerjee, Rohit Gaurav,Paromita Roy, Saugata Sen, Manas Roy, Soumendranath Ray


Tata Medical Center, Newtown, Rajarhat, Kolkata, West Bengal, India

Objective: The aim of this study was to evaluate the effectiveness of 18F FDG PET-CT in pre operative staging and assessment of the operability in patients of gall bladder cancer. Materials and Methods: 21 patients (10 males and 11 females, age range between 30 and 74) histopathologically diagnosed with carcinoma of gall bladder had undergone contrast enhanced 18F FDG PET-CT before curative or explorative surgery ranging from staging laparotomy to radical cholecystectomy or more extensive patial hepatectomy. Locoregional and distant lymphnodes were dissected routinely. Mean interval between PET-CT and surgery was 18.5 (0-37) days. Post-operative histopathological findings were correlated with 18F FDG PET-CT and operative findings under separate headings of primary lesion, locoregional lymph node, distal lymph node and distant metastatic lesion if any. Results: Analysis of data shows good correlation between PET-CT imaging, intraoperative findings and histopathological reports. The results are tabulated below under separate subheadings. (1) 18F FDG PET-CT findings in primary lesions are in agreement with histopathology report in 85% patients and with intraoperative findings in 80% cases. (2) 18F FDG PET-CT findings in regional lymphnodes are in agreement with histopathology report in72% patients and with intraoperative findings in 89% cases. (3) 18F FDG PET-CT findings in distant lymphnodes are in agreement with histopathology report in 88% patients and with intraoperative findings in 94% cases. (4) 18F FDG PET-CT findings in metastatic lesions are in agreement with histopathology report in 90% patients and with intraoperative findings in 66% cases. (2 out of 7 cases were true positive in histopathology). "Overall calculated agreement (including all parameters)-82%." Conclusion: Pre-operative 18F FDG PET-CT appears to be a very effective and useful investigation in pre-operative staging and assessment of the operability in patients of gall bladder cancer. High degree of correlation has been observed with intra-operative findings and histopathology report. More number of studies will help to reach a robust conclusion.

Pet -O-02

Dual time point 18F-fluorodeoxyglucose-positron emission tomography-computed tomography imaging in characterization of axillary node in breast cancer patients and its correlation to sentinel node biopsy and final histopathology

Madhur Kumar Srivastava, S Shelley, P Venkat 1 , M Indirani


Departments of Nuclear Medicine, and 1 Surgical Oncolgy, Apollo Hospitals, Chennai, Tamil Nadu, India

Aim of the Study: The purpose of this study was to assess the utility of dual-time-point 18 F-FDG PET-CT imaging for characterization of axillary lymph nodes in breast cancer patients and correlate with sentinel node and final histopathological examination. Materials and Methods : 35 patients with biopsy proven breast cancer presented for 18 F-FDG PET-CT study were included in the study. They underwent PET-CT scans at 60 min and 120 min post FDG injection. From this, the percentage change in standardized uptake value (∆%SUV max) between first and delayed scan was calculated for the axillary nodes. A cutoff value of change in SUV max of 5%, 10%, 15%, 20%, 25% and 30% was taken into account and the sensitivity, specificity, PPV, NPV and accuracy was calculated. The patients underwent sentinel node dissection and the FDG uptake in nodes was correlated with the result of frozen section and final histopathology. Results: 55 nodes were removed during surgery as sentinel nodes, of which, 33 were positive for metastases. The cutoff value of 15% ∆%SUV max for nodes showed the maximum accuracy when correlated with the sentinel node frozen section and on ROC analysis. There was a positive correlation between the positivity of nodes and SUV max of nodes in first scan (r = 0.4424; P < 0.05) and to ∆%SUV max of nodes (r = 0.3227, P < 0.05). Eight nodes showed micro metastases on final histopathology, all of which showed increase of ∆%SUV max. Distant metastases, not previously known, were seen in 8 patients. Conclusion: FDG PET-CT dual point imaging can be used to differentiate between malignant and benign nodes and 15% percentage increase in SUV max of axillary nodes showed maximum accuracy to differentiate between malignant and benign nodes.

Pet-O-03

Role of fluorine-18 fluorodeoxyglucose positron emission tomography in a case of renal cell carcinoma to differentiate tumor thrombus from bland thrombus

Sunita Sonavane, Deepa Rani, Ramesh Asopa, Gaurav Malhotra, Dilip Pawar


Radiation Medicine Centre, TMH Annexae, Parel, Mumbai, Maharashtra, India

Introduction: Tumor thrombus is a rare complication of many solid cancers including renal cell carcinoma, testicular tumor, adrenal cortical carcinoma, osteosarcoma, Ewing's sarcoma etc. A case of renal cell carcinoma with baseline Contrast enhanced computerized tomography (CT) KUB revealed 10 cm ×7 cm × 6 cm heterogeneously enhancing mass in the upper half of right kidney with tumour thrombus in the right renal vein and suprarenal inferior vena cava (IVC), crossing the cavoatrial junction, reaching upto the right atrium (grade IV). The suprarenal IVC thrombus shows similar enhancement on the renal mass and no enhancement in the infrarenal IVC and bilateral iliofemoral veins thrombus. The case was referred for fluorine-18 fluorodeoxyglucose (F-FDG) positron emission tomography (PET)/computerized tomography (CT) imaging for staging. Materials and Methods: CT scan was performed first, from skull base to proximal thighs, with 120 kV, 50 mAs, a tube rotation time of 5 mm section thickness, which was matched to the PET section thickness. PET image was acquired for 1 min per table position and data sets were reconstructed iteratively by applying the CT data for attenuation correction, and co-registered images were interpreted. Result: PET/CT reveal large irregular right renal mass, hypermetabolic grade IV tumor thrombus extending from the right renal vein to suprarenal inferior venacava reaching upto the right atrium. There was no FDG uptake noted in the infrarenal IVC and bilateral iliofemoral veins thrombus. PET/CT in this case ruled out any locoregional adenopathy or distant metastases and distinguished tumor thrombi from bland thrombi. Conclusion: F-FDG PET/CT not only aided in the staging but also discriminated between benign and malignant venous thrombi.

Pet -O-04

Paraneoplastic syndrome: A diagnostic challenge on fluorodeoxyglucose-positron emission tomography-computed tomography

Khushboo Y Gupta, BA Krishna, Rajnath Jaiswal


Department of Nuclear Medicine, Bombay Hospital and MRC, Mumbai, Maharashtra, India

Objective: Paraneoplastic syndrome (PNS) is a major diagnostic challenge. Patients usually present with neurological manifestations and often the MRI does not reveal any abnormality raising suspicion of PNS. In such a scenario the detection of primary malignant lesion would need extensive investigative approach. However with advent of FDG-PET/CT, the detection of unknown primary lesions has improved significantly. Hence we undertook a retrospective analysis to assess the role of 18F-FDG PET/CT in the evaluation of patients with PNS. Materials and Methods: Totally 29 patients were analysed.There were 18 males and 11 females. All patients underwent whole body FDG-PET/CECT using conventional protocol on Phillips TRU FLIGHT SELECT PET-CT system. Biopsy was performed in malignancy suspected patients while others were followed up clinically. Results: Among 29 patients, FDG-PET/CT was positive (abnormal tracer uptake) in 22 patients. Out of these, PET-CT scan revealed probable malignancy in 8/22 (36.3%), benign disease in 9/22 (40.9%) and 5/22 (22.7%) were equivocal. Of the 8 patients with probable malignancy, 6 were confirmed at histology (commonest malignancy was SCLC lung). In one patient PET-CT scan showed possible malignancy in mid third esophagus which however was negative on endoscopy. In another patient PET-CT scan did not reveal any extra-cranial abnormality, however the brain lesion seen on MRI was considered as suspicious for malignancy in view of high grade uptake. In 9/22 patients FDG-PET/CT favored infection probability and these patients were treated with antibiotics or steroids and no biopsy was performed. There were 5 equivocal PET/CT scans which either at histology or follow-up did not show any evidence of malignancy. Conclusion: In our study, FDG-PET-CT scan identified malignancy as the underlying cause in 27% of our patients with paraneoplastic syndrome. The most common malignancy site was lung.

Pet-O-05

Usefulness of fluorodeoxyglucose-positron emission tomography-computed tomography in patients with gastrointestinal lymphoma

Khushboo Gupta, BA Krishna, Natasha Singh, Madhusudan Vyas


Department of Nuclear Medicine, P.D. Hinduja National Hospital and MRC, Mumbai, Maharashtra, India

Objectives: In cases of gastro-intestinal lymphoma, the challenges faced during diagnosis on conventional imaging are extent of the disease, benign inflammation versus malignant disease and recurrence evaluation. We undertook this study to evaluate utility of FDG PET/CT in such cases. Materials and Methods: A total of 19 patients with gastro-intestinal NHL were studied, age ranging from 15 to 40 years. Histologically 14 patients had DLBCL, 3 had Burkitt's NHL, 2 were MALT and 1 was anaplastic. We analysed patients in 3 groups: Group I included 3 patients for pre-treatment staging, Group II had 7 patients for response evaluation post chemotherapy and Group III consisted of 9 patients who were on follow-up post treatment. Conventional whole body FDG PET/CT scan was performed in all the patients. All patients were followed either on biopsy, clinical assessment and/or further institution of therapy. Results: In Group I (n = 3), PET/CT was positive on all 3 patients and upstaged 1/3 patient. In Group II (n = 7) PET/CT showed true responders in 6/7 patients (85.7%) and true partial responders in 1 patient. In Group III (n = 9) PET/CT detected true disease recurrence proved on biopsy in two patients - One at the colon anastmotic site where CT was negative and the other in stomach where initially biopsy had revealed gastritis. False positive detection was seen in 2 patients: One had liver lesion and another had disease in ileum anastmotic site. Rest of the patients with true remission on PET/CT did well clinically. Conclusions: The implications of FDG PET/CT study in cases of gastro-intestinal lymphoma offers valuable information, better than other conventional imaging, in pre-treatment staging, post treatment response evaluation and specially highlighting in our study the issue of disease recurrence, hence yielding results decisive for management.

Pet -O-06

Can SUV-MAX of a primary breast lesion be a substitute predictive/prognostic marker?

Kalshetty Ashwini


P.D. Hinduja National Hospital, Mahim, Mumbai, Maharashtra, India

Objective: To evaluate the relation of SUVmax of primary breast lesion to the established prognostic/predictive markers of breast cancer like age, stage and grade of tumour, hormonal status, Her2 status, Ki67 index on histopathology and immunohistochemistry of tumour. Materials and Methods: In this single institution study included patients who had their PET-CT studies from 01/01/2008 to 31/01/2013 at Hinduja Hospital and underwent all workup and treatment for evaluation of their complete HH records. 45 women (age range of 27-85 years) irrespective of menopausal status and stage who had staging PET-CT study with histopathologically proven breast cancer (infiltrating duct carcinoma) of all stages but with no evidence of distant metastases on PET study were included in this study. All data was segregated by SUVmax against variables like age, ER, PR, Her2 status, pTsizes, Grades of tumour, and Ki67 indices. Continuous data was reported as mean ± S.D. Correlation tests like Mann Whitney U test, and linear regression analysis were applied and 'P' values were obtained. P < 0.05 was considered as statistically significant. Results: Patients showed a tendency of higher SUV values in younger and older age groups with no significant difference. When compared with the T stage of tumours, pT2 had higher SUV value (P = 0.0006), pT3 (P = 0.014). Higher grades of tumour had higher SUVs; grade 3 (P = 0.007), grade 2 (P = 0.2). Triple negative and HER2 like tumours showed higher SUVs than luminal subtypes (P = 0.03). However, there was no significant relationship with Ki-67 index with preponderance of higher SUVs in higher indices. Conclusions: Hence, overall there was a tendency of higher SUV values in poorer prognostic groups suggesting a correlation of glucose metabolism and tumour micro-environment or the various factors modifying it. PET CT is a noninvasive tool which can provide an incremental value over staging by giving indirect prognosis.

Pet-O-07

Does fluorodeoxyglucose-positron emission tomography-computed tomography help in correctly identifying grade of chondrosarcomas and thereby preventing the need for biopsy

Mandakinee Phukan, Natasha Singh


Department of Nuclear Medicine, P.D. Hinduja National Hospital and Medical Research Centre, Mumbai, Maharashtra, India

Objective: (1) To evaluate potential of FDG PET-CT with regard to SUV in differentiating different grades of chondrosarcoma and to find whether SUVmax correlates with the postsurgery histopathology (2) To determine whether FDG PET-CT helps to avoid biopsy in cases of chondrosarcoma. Materials and Methods: The study was retrospectively carried out in 27 patients (17 males and 10 females) with suspicion of cartilaginous tumors, especially chondrosarcoma. All the 27 patients were investigated with either X-ray/CT scan/MRI. Presurgery biopsy was available in 20 patients. FDG PET-CT was performed in all patients prior to treatment. All patients underwent surgical management and histopathological diagnosis was confirmed in all cases. Results: SUVmax ranged from 0.9 to 2.8 in 7 tumors of Grade I, 1.7 to 12.7 in 17 tumors of Grade II, 5.8 to 38 in three tumors of dedifferentiated chondrosarcoma. An overlap in SUVmax was found in two patients. In comparison of grade of chondrosarcoma as per SUVmax and postsurgery histopathology, there was 100% concordance between the two methods in grade I and dedifferentiated tumors and 88.2% in grade II tumors. There was discordance between presurgery biopsy and post surgery histopathology in one tumor of grade I, 13 tumors of grade II and one tumor of dedifferentiated chondrosarcoma. Thus accuracy rate of presurgery biopsy was only 25%. Conclusion : The study demonstrates the utility of including 18F FDG PET-CT scan in diagnostic armamentarium of chondrosarcoma patients. Pretreatment tumor SUVmax is a highly sensitive parameter for determining the grade of chondrosarcoma and thereby impacts the decision for optimal surgical management.

Pet-O-08

The diagnostic utilization of 18F-fluorodeoxyglucose-positron emission tomography-computed tomography for characterization of adrenal lesions in oncological patient

Parghane Rahul, Sunil Kumar, BR Mittal, A Bhattacharya, B Singh


Department of Nuclear Medicine, PGIMER, Chandigarh, India

Aim: The aim of this study was to evaluate the usefulness of 18 F-FDG PET/CT scan for characterizing adrenal lesion in oncological patient using quantitative standardized uptake value (SUV) value. Materials and Methods: We analyzed oncological patients retrospectively; who were underwent 18 F-FDG PET/CT from 2010 to 2012 for various oncological indications. This study include 71 patients who were underwent 18 F-FDG PET/CT and regional CT scan within 1 months of PET/CT and found to have abnormal adrenal lesions. There were 48 males and 23 females with age range between 16 and 87 years with average age of 60 years. Out of 71 patients, 29 patients had non small cell lung carcinoma, 2 patients-small cell lung carcinoma, 14 patients- RCC, 6 patients- NHL, 5 patients- Ca breast, 3 patients- Ca rectum, 3 patients- Ca gall bladder, 2 patients- Ca esophagus, 1 each patient had Ca colon, Ca cervix, HCC, uterine carcinoma, liposarcoma, small intestine tumor and Ca stomach. Out of 71 patients, 27 patients were underwent 18 F-FDG PET/CT for initial staging, 20 patients for detection of recurrence, 23 patients for therapy response evaluations and 1 patient for surveillance. 18 F-FDG PET/CT was performed using standard protocol. Whole body imaging (base of skull to mid thigh region) was performed in 71 patients. For quantitative PET analysis, ROI was drawing on adrenal gland for calculation of maximum standardized uptake value (SUV) value. The sensitivity, specificity and accuracy for distinguishing malignant lesions from benign adrenal lesions were calculated for each investigation. Result : Final diagnosis for malignant lesion was based on histology examination (14 patients), follow-up PET scan after therapy (23 patients), wide spread metastasis in 18 F-FDG PET/CT and clinical follow-up (34 patients). Based on these features, 12 patients were finally diagnosed as benign adrenal lesions and 59 patients as malignant adrenal lesions. The range of SUVmax was 1.3 to 20 with average of 6.7. The mean diameter of adrenal lesion was 2.3 cm (range, 0.7-8.6 cm) on regional CT images. The sensitivity, specificity and accuracy for diagnosis of malignant adrenal lesions by using SUVmax >3 as cut off was 96%, 66% and 91% respectively for 18 F-FDG PET/CT scan and the sensitivity, specificity and accuracy for diagnosis of malignant adrenal lesions by using size >1.5 as cut off was 70%, 25% and 61% respectively for CT scan. Conclusion: 18 F-FDG PET/CT is a highly sensitivity and accurate method for differentiating malignant lesion from benign adrenal lesions by using quantitative PET analysis (SUVmax) as compared to regional CT scan based on size in oncology patients. This lead to avoid for further evaluation of adrenal lesions in oncological patients.

Pet-O-09

Does 18F-fluorodeoxyglucose-positron emission tomography-computed tomography predict pathological response post neoadjuvant chemotherapy in locally advanced breast cancer?

Smita Krishnamurty Moodi, Divya Naresh Shivdasani, Natasha Singh Dawra, Ashish Rajendra Ghuli


Department of Nuclear Medicine, P.D. Hinduja National Hospital and MRC, Mumbai, Maharashtra, India

Objective: To evaluate the role of 18F-FDG PET-CT in the assessment of pathological response to neoadjuvant chemotherapy (NACT) in locally advanced breast cancer. Materials and Methods: Fifteen patients (age range 39-63 years Mean-53.26) with pretreatment clinical and imaging findings suggestive of locally advanced breast cancer without distant metastases were included in this study. Whole body PET-CT was performed at staging and post NACT (3 or 4 cycles). All patients underwent surgery (WLE or MRM + AC) post NACT. Histopathology was analyzed for residual viable tumor. Results: 1/15 patients (6.66%) had lobular carcinoma while remaining 14 patients (93.33%) had ductal carcinoma on histopathology. The SUV max of the primary breast lesion on staging PET-CT was in the range of 6.8-31.4 (Mean-15.25) and the primary lesion in lobular carcinoma had the SUV max of 4.7. On post NACT PET-CT, the quantitatively significant uptake greater than mediastinal blood pool activity was considered as residual disease. 4/15 (26.66%) patients had resolution of disease activity on PET-CT with no residual viable tumor on histopathology. Rest of the patients (73.33%) showed partial response with decrease in SUV max on PET-CT and evidence of chemotherapeutic effect (necrosis, hyalinization) with residual viable tumor on histopathology. None of the patients showed disease progression. Conclusion: FDG PET CT allows for accurate prediction of treatment response to NACT in locally advanced breast cancer.

Pet-O-10

Role of 18F fluorodeoxyglucose-positron emission tomography-computed tomography in suspected cases of paraneoplastic neurological syndrome

Nitin Gupta, Arun Sasi Kumar, Rajender, Ashwini Sood, Anish Bhattacharya, Baljinder Singh, BR Mittal


Department of Nuclear Medicine, PGIMER, Chandigarh, India

Aim : To evaluate the role of FDG PET/CT in suspected paraneoplastic neurological syndrome (PNS). Background: Paraneoplastic neurological syndrome is a clinical condition presenting with varied symptoms and poses diagnostic difficulties. Patients presenting with neurological symptoms leading to a clinical suspicion of paraneoplastic syndrome is a diagnostic dilemma most often. In most of the patients the underlying tumor often remains unidentified with conventional imaging procedures. Paraneoplastic antibodies are helpful for identifying the primary lesion in patients with paraneoplastic syndrome. However the diagnosis could be reached only in about 50% of the patients. Detection of underlying malignancy is extremely important as it identifies the treatable cause of patients symptoms. We evaluated the usefulness of (18) F-FDG-PET/CT in identifying a primary malignancy in cases of suspected paraneoplastic neurological syndromes. Materials and Methods : We retrospectively evaluated 45 patients, who were referred to nuclear medicine department from neurology department from November 2011 to July 2013. Analysis of PET/CT findings and its usefulness for identifying malignancy as well as non malignant causes that were responsible for the patient's symptoms were done. Results: On combined PET/CT focal abnormal (18) F-FDG uptake was noted in 7 out of 45 patients. Out of these 7 patients combined PET/CT identified the underlying primary disease which was biopsy proven in 7 patients (one patient had sarcoidosis, one had tuberculosis and 2 patients had adenocarcinoma lung, 1 had transitional cell carcinoma urinary bladder, 1 patient had malignant carcinoid lung, and 1 patient had carcinoma ascending colon. Conclusions : In the present study the (18) F FDG PET/CT could identify underlying malignancy as the cause of suspected PNS in 11% patients (5/45). It also provided alternative useful diagnosis in 4% (2/45) patients. FDG PET/CT is a useful tool in the evaluation of cases of suspected PNS especially when other imaging modalities have been non contributory.

Pet-O-11

Initial experience of 68Ga-DOTATATE positron emission tomography - computed tomography scintigraphy in pituitary tumours

Regi Oommen, Danie Kingsley Heck, Julie Hephzibah, Nylla Shanthly, Ari G Chacko 1

Departments of Nuclear Medicine, and 1 Neurological Sciences, Christian Medical College, Vellore, Tamil Nadu, India

Objectives: 68Ga DOTATATE PET-CT scintigraphy (DS) is rapidly gaining popularity for evaluation of somatostatin receptor (SSR) expressing tumours such as neuroendocrine tumours and meningioma. Utility of this method of functional imaging for pituitary tumours, known to express SSR is not studied. Materials and Methods: Patients with pituitary tumours underwent DS either for pre-operative study or for study of post-operative residual lesion. Data from additional imaging like CT and/or MRI and 18F-FDG PET-CT imaging were also available, in addition to biochemical assays of pituitary hormones for final diagnosis. Results: In 11 patients, 3 had suspected recurrence after excision of growth hormone (GH) producing adenoma. Two patients had positive DS and normal residual half of pituitary gland in one patient. Correlative imaging confirmed these findings. Six patients with ACTH induced Cushing's syndrome - 3 patients post-operative, one showed residual tumour (true positive), and false negative in the other two patients; 3 pre-operative patients - physiological uptake in DS in all of them. One patient suspected of ectopic ACTH producing tumour had physiological uptake in DS; and one patient with suspected post-operative residual lesion revealed physiological uptake in residual half of pituitary gland (true negative). MRI identified small tumours in the sella in 3 out 6 patients with negative DS. Conclusion: In this study of small group of patients, DS was found to be a useful tool in pre-operative evaluation of GH producing pituitary adenomas. The results of DS were equivocal in ACTH producing tumours and Cushing's syndrome.

Pet-O-12

Role of 68 Ga-DOTA-NOC positron emission tomography-computed tomography in detection of unknown primary neuroendocrine tumors

Charu Jora, V Kousik, Promila Pankaj, Ritu Verma,Anjali Jain, Ethel Belho, Parul Gupta


Department of Nuclear Medicine, Sir Gangaram Hospital, New Delhi, India

Purpose: This study aimed to determine the role of 68 Ga-DOTA-NOC PET/CT in the detection of undiagnosed primary sites of neuroendocrine tumors (NETs) and to understand the tumor biology of the primarily undiagnosed tumors. Materials and Methods : Overall 47 patients (29 men and 18 women, age: 50 ± 9 years) with documented NET metastases and unknown primary were enrolled. PET/CT was performed after injection of approximately 100 MBq (46-260 MBq) of 68 Ga-DOTA-NOC. Any area with intensity greater than background was considered to be indicative of tumour tissue and the maximum standardised uptake values (SUVmax) were calculated. CECT was done in all the patients prior to PET/CT study and the results were compared. Results In 37 of 47 patients (78%), 68 Ga-DOTA-NOC PET/CT localised the site of the primary: Stomach (2), duodenum (9), jejunum (6), ileum (1), pancreas(7) (Head (2), Neck (1), uncinate process(1), body (1) and tail (2)), rectum (5), lungs (2), kidney (2), gall bladder (2) and prostate (1). Size of primary tumor was less than 2 cm in 17 of 37 detected cases. Focal 68 Ga-DOTA-NOC uptake at the site of primary without underlying CT abnormality was seen in 3 cases. Rare sites of primary NET in gall bladder, horseshoe kidney and prostate were identified. Besides the usual metastases to lymph nodes, liver and bone, atypical metastases to lung, pancreas, adrenal gland, spleen, orbit, brain and bone marrow were detected in some cases. Osteolytic bone metastases were detected in few cases. Portal vein thrombus and splenic vein thrombus were additional findings in three cases. CT alone (on retrospective analyses) confirmed the findings in only 12 of 47 patients (25 %). 6/47 patients with loco regional disease on PET/CT underwent surgical resection of disease. 21/47 with DOTA-NOC avid disease were started on sandostatin injections. 11/47 with mild DOTA-NOC uptake were managed with systemic chemotherapy. Conclusion: Our study shows that 68 Ga-DOTA-NOC PET/CT detects both usual and unusual sites of primary tumor and metastases. Tumor size is an unreliable predictor of metastatic potential, as metastases is seen in primary tumors less than 1 cm in diameter. Early detection of rare atypical sites of primary NET like kidney and gall bladder helps in individualising treatment approach. DOTA-NOC avidity and disease extent helps in systematic management of patients as seen in this study. Our data clearly indicate that 68 Ga-DOTA-NOC PET/CT is a promising imaging modality for evaluation of patients with CUP-NET.




 

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