MRI of carcinoid tumors: Spectrum of appearances in the gastrointestinal tract and liver

Abstract

The purpose of this study was to evaluate the spectrum of appearances of gastrointestinal carcinoid tumors at magnetic resonance imaging (MRI) and to elucidate patterns of appearances of carcinoid liver metastases on precontrast and postgadolinium images. The MR examinations of 29 patients (11 men, 18 women; age range, 33-87 years) with histologically confirmed gastrointestinal carcinoid tumors, representing our complete 9.5 years of experience with this entity, were retrospectively reviewed. Twelve patients had MR examinations prior to resection or biopsy of the primary tumor (preoperative group); 17 patients were imaged postsurgically (postoperative group). All MR studies were performed at 1.5 T and comprised T1-weighted spoiled gradient echo (SGE), T2-weighted fat-suppressed turbo spin echo, HASTE, and serial postgadolinium T1-weighted SGE sequences without and with fat suppression. Morphology, signal intensity, and contrast enhancement of primary tumors and of metastases to the mesentery, peritoneum, and liver were evaluated. Primary tumors were visualized in 8 of 12 patients and best demonstrated on postgadolinium T1-weighted fat-suppressed images. The appearance of primary tumors was a nodular mass originating from the bowel wall (4 of 12 patients) or regional uniform bowel wall thickening (4 of 12 patients) with moderate intense enhancement on postgadolinium images. In 4 of 12 patients the primary tumor was prospectively not seen. Mesenteric metastases, seen in eight patients, presented as nodular masses and were associated with mesenteric stranding in seven patients. A total of 156 liver metastases were evaluated in 16 patients. On precontrast T1-and T2-weighted images, 117 metastases (75%) were hypointense and hyperintense, respectively. A total of 146 metastases (94%) were hypervascular, showing moderate intense enhancement during the hepatic arterial phase, and 9 metastases (6%) were hypovascular. Twentythree metastases (15%) were visible only on immediate postgadolinium images. MRI is able to demonstrate findings in carcinoid tumors, including the primary tumor, mesenteric metastases, and liver metastases. Liver metastases are commonly hypervascular and may be demonstra-

Imaging of gastroenteropancreatic neuroendocrine tumors

“…Similarly, hepatic metastases are well depicted on MRI, and MRI is often used to further characterize lesions that are equivocal on CT. Like the primary lesions, hepatic metastases appear as T1 hypointense and T2 hyperintense. Bader et al [36] showed this finding in 75% of cases. Interestingly, 15% of cases showed increased enhancement only in the arterial phase.…”

“…Gastrinomas tend to show ring or peripheral enhancement while most other subtypes of NETs demonstrated a diffuse pattern of enhancement. For GI NETs, MRI is able to detect around two-thirds of lesions [36] , with fat-suppressed T1W imaging yielding maximal results. Similarly, hepatic metastases are well depicted on MRI, and MRI is often used to further characterize lesions that are equivocal on CT. Like the primary lesions, hepatic metastases appear as T1 hypointense and T2 hyperintense.…”

Computer Tomography and Magnetic Resonance Image Manifestations of Primary Hepatic Neuroendocrine Cell Carcinomas

“…(Pilichowska et al, 1999;Modlin et al, 2008;Yao et al, 2008;Zeng et al, 2013). Liver neuroendocrine carcinoma found in clinical mostly induced by the intestines and pancreas transfer, PHNEC was very rare originating in the liver (Pilichowska et al, 1999;Tohyama et al, 2005;Hamanaka et al, 2012;Yalav et al, 2012), accounting for 1%-5% of all liver cancer, and 0.8% -4.0% of systemic neuroendocrine tumors, the imaging findings were lack of specificity, leading to difficultly preoperative diagnosis (Pilichowska et al, 1999;Bader et al, 2001;Tohyama et al, 2005;Ulusan et al, 2005;Krohn et al, 2011;Yalav et al, 2012;Baek et al, 2013). Patients generally did not have carcinoid syndrome and were lack of specific clinical symptoms and signs.…”

“…Primary liver cell neuroendocrine carcinoma was a rare primary liver cancer, the imaging performance was still lack of awareness and understanding, resulting in often misdiagnosis (Bader et al, 2001;Ulusan et al, 2005;Rufini et al, 2006;Krohn et al, 2011;Baek et al, 2013;Li et al, 2013). The main differential diagnosis was primary hepatocellular carcinoma and bile duct carcinoma (Kim et al, 2011;Yalav et al, 2012;Li et al, 2013).…”

“…Both the clinical symptoms and imaging findings were not specific, resulting in difficult for preoperative diagnosis. Most previous studies reported in the literature were about individual case (Pilichowska et al, 1999;Tohyama et al, 2005;Yalav et al, 2010;Hamanaka et al, 2012), no reports were about the features of CT and MRI imaging for bulk cases with PHNEC (Bader et al, 2001;Ulusan et al, 2005;Rufini et al, 2006;Krohn et al, 2011;Baek et al, 2013;Li Department of Radiology, West China Hospital, Sichuan University, Chengdu, Sichuan, China *For correspondence: jianqunyucn@163.com …”