Indian Journal of Nuclear Medicine

INTERESTING IMAGE
Year
: 2014  |  Volume : 29  |  Issue : 2  |  Page : 122--123

Carcinoma of unknown primary of neuroendocrine origin: Accurate detection of primary with 68 Ga-labelled [1, 4, 7, 10-tetraazacyclododecane-1, 4, 7, 10-tetraacetic acid]-1-NaI3-Octreotide positron emission tomography/computed tomography enterography


Tarun Kumar Jain, Sellam Karunanithi, Varun Singh Dhull, Shambo Guha Roy, Rakesh Kumar 
 Department of Nuclear Medicine, All India Institute of Medical Sciences, New Delhi, India

Correspondence Address:
Rakesh Kumar
Department of Nuclear Medicine, All India Institute of Medical Sciences, New Delhi - 110 029
India

Abstract

68 Ga-labelled [1, 4, 7, 10-tetraazacyclododecane-1, 4, 7, 10-tetraacetic acid]-1-NaI3-Octreotide ( 68 Ga-DOTANOC) positron emission tomography/computed tomography (PET/CT) is an excellent modality in patients with carcinoma of unknown primary of neuroendocrine origin. Most of the primary lesions are located in mid gut region where the lesions have poor resolution due to undistended and overlapping intestinal loops and motility-related artifacts. Although PET/CT enteroclysis, enterography and colonography have been described with 18 F-fluorodeoxyglucose, PET/CT enterography with 68 Ga-DOTANOC has not been described in the literature. Here, we present a case where 68 Ga-DOTANOC PET/CT enterography was useful in identifying the primary neuroendocrine tumor lesion in small intestine with accurate delineation.



How to cite this article:
Jain TK, Karunanithi S, Dhull VS, Roy SG, Kumar R. Carcinoma of unknown primary of neuroendocrine origin: Accurate detection of primary with 68 Ga-labelled [1, 4, 7, 10-tetraazacyclododecane-1, 4, 7, 10-tetraacetic acid]-1-NaI3-Octreotide positron emission tomography/computed tomography enterography.Indian J Nucl Med 2014;29:122-123


How to cite this URL:
Jain TK, Karunanithi S, Dhull VS, Roy SG, Kumar R. Carcinoma of unknown primary of neuroendocrine origin: Accurate detection of primary with 68 Ga-labelled [1, 4, 7, 10-tetraazacyclododecane-1, 4, 7, 10-tetraacetic acid]-1-NaI3-Octreotide positron emission tomography/computed tomography enterography. Indian J Nucl Med [serial online] 2014 [cited 2019 Nov 14 ];29:122-123
Available from: http://www.ijnm.in/text.asp?2014/29/2/122/130320


Full Text

We present a case of 73-year-old male patient who presented with the complaints of weight loss and flushing for 6-7 months. Hematological parameters including erythrocyte sedimentation rate, fasting blood sugar and thyroid function tests were normal. An initial abdominal ultrasound revealed multiple hypoechoic lesions in bilateral lobes of liver and multiple enlarged mesenteric lymph nodes. Contrast enhanced computed tomography abdomen and chest revealed the same extent of disease. Patient underwent fine-needle aspiration cytology (FNAC) of liver lesion, which revealed metastatic neuroendocrine tumor. Serum chromogranin A (CgA) level was also elevated (CgA ~ 656.46 U/ml). Colonoscopy was performed in search of primary and found to be normal. Finally the treating oncologist advised 68 Ga-labelled (1, 4, 7, 10-tetraazacyclododecane-1, 4, 7, 10-tetraacetic acid)-1-NaI3-Octreotide ( 68 Ga-DOTANOC) positron emission tomography/computed tomography (PET/CT) in order to search for primary tumor and to define the disease extent. 68 Ga-DOTANOC PET/CT was performed which revealed metastatic 68 Ga-DOTANOC avid lesions in liver and mesenteric lymph nodes [Figure 1]a. Multifocal DOTANOC uptake in the region of distal ileum was also noted [Figure 1]b-e. For better delineation of the small intestinal lesion, we performed PET/CT enterography by orally administrating 100 ml of polyethylene glycol (PEG) mixed in 1 l of water. After 1 h of PEG administration, 68 Ga-DOTANOC was injected intravenously and a spot view of abdomen was acquired after 45-50 min. The preparation is arranged in a manner that whole procedure including the scan was completed within 2 h. 68 Ga-DOTANOC PET/CT enterography helped in accurate delineation of the ileal lesions in the background of distended intestinal loops [Figure 1]f-i. FNAC/biopsy was not accessible as the lesions were located in the distal ileum. He was put on somatostatin based therapy in view of metastatic disease.{Figure 1}

68 Ga-DOTANOC PET/CT is a better modality in patients with carcinoma of unknown primary of neuroendocrine origin. [1] Most of the primary lesions are located in a midgut region and mid gut lesions have a poor resolution due to undistended and overlapping intestinal loops and motility-related artifacts. For better delineation and evaluation of intestinal lesions, a complete evaluation of lumen, wall and adjacent structures of gut is required. Both CT and magnetic resonance enteroclysis depict mucosal abnormalities and extra intestinal complications in a highly accurate way but these fail to show the metabolic status of the disease. [2] Therefore, we conceptualized a fusion of a metabolic imaging technique like PET and an anatomical imaging modality like CT enterography to derive information both on the morphology and the functional activity of the lesions at the same time. [3] Although PET/CT enteroclysis, enterography and colonography have been described with 18 F-fluorodeoxyglucose, [3],[4],[5] PET/CT enterography with 68 Ga-DOTANOC has not been described in the literature. Here in this case, 68 Ga-DOTANOC PET/CT enterography was useful in identifying the primary lesion in small intestine with accurate delineation.

References

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5Das CJ, Makharia GK, Kumar R, Kumar R, Tiwari RP, Sharma R, et al. PET/CT colonography: A novel non-invasive technique for assessment of extent and activity of ulcerative colitis. Eur J Nucl Med Mol Imaging 2010;37:714-21.