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Everything you need to know about Computed Tomography (CT) & CT Scanning

Small Bowel: Neuroendocrine Tumor Imaging Pearls - Educational Tools | CT Scanning | CT Imaging | CT Scan Protocols - CTisus
Imaging Pearls ❯ Small Bowel ❯ Neuroendocrine tumor

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  • “Neuroendocrine tumors occur most commonly in the small bowel, especially the distal ileum; 40% of them are found within 60 cm of the ileocecal valve. Arterial phase CT scanning is useful for the detection of small bowel neuroendocrine tumors, because the tumors usually present with small hyperenhancing masses (30% of these are multiple at diagnosis). Neuroendocrine tumor cells tend to show infiltrative growth through the small bowel wall into the adjacent mesentery, causing mesenteric fibrosis with the encasement of mesenteric vessels that subsequently results in bowel ischemia. If the primary tumor is larger than 2 cm, nodal metastasis and liver metastasis occur in more than 80% and 40% of tumors, respectively.”
    Tumors of the jejunum and ileum: a pattern‐based imaging approach on CT
    Kim SW et al.
    Abdominal Radiology (2019) 44:2337–2345
  • "Several small bowel tumors, such as hemangiomas, small GISTs, neuroendocrine tumors, and malignant gastrointestinal neuroectodermal tumors (GNETs), usually appear as well-enhanced masses. Because the imaging features of metastases usually depend on those of the primary tumor, hypervascular small bowel masses may be metastases of hypervascular primary cancer.”
    Tumors of the jejunum and ileum: a pattern‐based imaging approach on CT
    Kim SW et al.
    Abdominal Radiology (2019) 44:2337–2345
  • “Emergent biphasic MDCT demonstrated low but non-trivial yield (11.1%) for the depiction of suspected acute mesenteric ischemia but was particularly low for occlusive venous AMI (0.9%). The relationship between serum lactate elevation and positive MDCT findings of AMI in our study conforms to prior work and cautiously suggests value in routine serum lactate assessment preceding imaging for patient prioritization.”
    Utility of biphasic multi-detector computed tomography in suspected acute mesenteric ischemia in the emergency department
    Gopee-Ramanan P et al.
    Emergency Radiology (2019) 26:523–529
  • “In light of serum lactate as an established prognosticator for increased all-cause mortality and emerging as a generally concerning metric when suspecting AMI, consistent ordering of serum lactate prior to MDCT assessment for AMI may potentially help expedite triaging of sicker patients. For example, knowledge of patients’ serum lactate elevation at the time of protocolling and performing emergent MDCTs from the ED for suspected AMI could expedite preferential diagnostic reporting of the given patients’ scans at the console or at the workstation by the responsible radiologist, thereby minimizing time to management.”
    Utility of biphasic multi-detector computed tomography in suspected acute mesenteric ischemia in the emergency department
    Gopee-Ramanan P et al.
    Emergency Radiology (2019) 26:523–529
  • “The approach to assessment of the utility of MDCT of AMI in the ED setting is highly relevant to daily practice. The combination of a low but non-trivial yield of biphasic MDCT for AMI of 11.1% and only a 0.9% yield for venous-occlusive ischemia at our institution lays ground- work for further investigation into CT protocols to possibly further reduce patient radiation dose, reduce the numbers of images to review, and reduce unnecessary delays in patient work-up and in surgical versus non-surgical management.”
    Utility of biphasic multi-detector computed tomography in suspected acute mesenteric ischemia in the emergency department
    Gopee-Ramanan P et al.
    Emergency Radiology (2019) 26:523–529
  • “Neuroendocrine tumors occur most commonly in the small bowel, especially the distal ileum; 40% of them are found within 60 cm of the ileocecal valve. Arterial phase CT scanning is useful for the detection of small bowel neuroendocrine tumors, because the tumors usually present with small hyperenhancing masses (30% of these are multiple at diagnosis). Neuroendocrine tumor cells tend to show infiltrative growth through the small bowel wall into the adjacent mesentery, causing mesenteric fibrosis with the encasement of mesenteric vessels that subsequently results in bowel ischemia. If the primary tumor is larger than 2 cm, nodal metastasis and liver metastasis occur in more than 80% and 40% of tumors, respectively.”
    Tumors of the jejunum and ileum: a pattern‐based imaging approach on CT
    Kim SW et al.
    Abdominal Radiology (2019) 44:2337–2345
  • "Several small bowel tumors, such as hemangiomas, small GISTs, neuroendocrine tumors, and malignant gastrointestinal neuroectodermal tumors (GNETs), usually appear as well-enhanced masses. Because the imaging features of metastases usually depend on those of the primary tumor, hypervascular small bowel masses may be metastases of hypervascular primary cancer.”
    Tumors of the jejunum and ileum: a pattern‐based imaging approach on CT
    Kim SW et al.
    Abdominal Radiology (2019) 44:2337–2345
  • “Emergent biphasic MDCT demonstrated low but non-trivial yield (11.1%) for the depiction of suspected acute mesenteric ischemia but was particularly low for occlusive venous AMI (0.9%). The relationship between serum lactate elevation and positive MDCT findings of AMI in our study conforms to prior work and cautiously suggests value in routine serum lactate assessment preceding imaging for patient prioritization.”
    Utility of biphasic multi-detector computed tomography in suspected acute mesenteric ischemia in the emergency department
    Gopee-Ramanan P et al.
    Emergency Radiology (2019) 26:523–529
  • “In light of serum lactate as an established prognosticator for increased all-cause mortality and emerging as a generally concerning metric when suspecting AMI, consistent ordering of serum lactate prior to MDCT assessment for AMI may potentially help expedite triaging of sicker patients. For example, knowledge of patients’ serum lactate elevation at the time of protocolling and performing emergent MDCTs from the ED for suspected AMI could expedite preferential diagnostic reporting of the given patients’ scans at the console or at the workstation by the responsible radiologist, thereby minimizing time to management.”
    Utility of biphasic multi-detector computed tomography in suspected acute mesenteric ischemia in the emergency department
    Gopee-Ramanan P et al.
    Emergency Radiology (2019) 26:523–529
  • “The approach to assessment of the utility of MDCT of AMI in the ED setting is highly relevant to daily practice. The combination of a low but non-trivial yield of biphasic MDCT for AMI of 11.1% and only a 0.9% yield for venous-occlusive ischemia at our institution lays ground- work for further investigation into CT protocols to possibly further reduce patient radiation dose, reduce the numbers of images to review, and reduce unnecessary delays in patient work-up and in surgical versus non-surgical management.”
    Utility of biphasic multi-detector computed tomography in suspected acute mesenteric ischemia in the emergency department
    Gopee-Ramanan P et al.
    Emergency Radiology (2019) 26:523–529
  • Neuroendocrine Tumors of the Duodenum: Facts
    Duodenal neuroendocrine tumors (NETs) comprise 2–3% of all GI endocrine tumors and are increasing in frequency. These include gastrinomas, somatostatinomas, nonfunctional NETs, gangliocytic paragangliomas, and poorly differentiated NE carcinomas. Although, the majority are nonfunctional, these tumors are a frequent cause of Zollinger-Ellison syndrome and can cause other clinical hormonal syndromes (carcinoid, Cushing's, etc.).
  • “Duodenal carcinoid tumors commonly appear as an enhancing mass in either the arterial or venous phases. If a primary tumor is not seen in the duodenum, adjacent enhancing lymphadenopathy can be a clue to the presence of a duodenal carcinoid tumor.”
    Duodenal neuroendocrine tumors: retrospective evaluation of CT imaging features and pattern of metastatic disease on dual-phase MDCT with pathologic correlation.
    Tsai SD, Kawamoto S, Wolfgang CL, Hruban RH, Fishman EK
    Abdom Imaging. 2015 Jun;40(5):1121-30
  • The incidence of neuroendocrine tumors of the GI tract has increased in the last few decades which may in part be due to the increased detection of tumors with wider availability of thin-section multi-detector computed tomography (CT) and endoscopy. For instance, a study based on a national population-based cancer registry in England found the incidence rate of neuroendocrine tumors in the GI tract increased 3- to 4-fold from 1971 to 2006 with an increase of fivefold in the duodenum in men and 6.7-fold in the duodenum in women. This underscores the importance of imaging tests in the primary diagnosis and staging of GI neuroendocrine tumors.
    Duodenal neuroendocrine tumors: retrospective evaluation of CT imaging features and pattern of metastatic disease on dual-phase MDCT with pathologic correlation.
    Tsai SD, Kawamoto S, Wolfgang CL, Hruban RH, Fishman EK
    Abdom Imaging. 2015 Jun;40(5):1121-30
  • Most duodenal carcinoids are sporadic but may be associated with clinical syndromes such as multiple endocrine neoplasia type 1 (MEN-1) and neurofibromatosis type 1(NF-1) . Two-thirds of duodenal neuroendocrine tumors are gastrinomas and one-third of these are functioning tumors manifesting as Zollinger–Ellison syndrome (ZES). The next most common type (20%) of duodenal neuroendocrine tumors is somatostatinomas. Other more rare types of neuroendocrine tumors are nonfunctioning serotonin-, gastrin-, or calcitonin-producing tumors and gangliocytic paragangliomas. Somatostatinomas are strongly associated with NF-1 as up to 50% of patients with somatostatinomas have NF-1. Somatostatinomas associated with NF-1 are usually found around the ampulla, and they histologically often contain psamomma bodies.
    Duodenal neuroendocrine tumors: retrospective evaluation of CT imaging features and pattern of metastatic disease on dual-phase MDCT with pathologic correlation.
    Tsai SD, Kawamoto S, Wolfgang CL, Hruban RH, Fishman EK
    Abdom Imaging. 2015 Jun;40(5):1121-30
  • Our results show that duodenal carcinoid tumors enhance during the arterial phase of intravenous-contrasted enhanced CT and although they do lose contrast enhancement during the venous phase (30.4%) as has often been previously reported; however, in a significant percentage (60.9%), there was an increase in contrast enhancement during the venous phase and no change in contrast enhancement in the venous phase in 8.7% of patients. Early-phase arterial enhancement pattern is an important criterion in distinguishing a duodenal carcinoid tumor from other duodenal masses such as adenocarcinoma which is usually hypovascular, adenomas, or other peri-ampullary masses.
    Duodenal neuroendocrine tumors: retrospective evaluation of CT imaging features and pattern of metastatic disease on dual-phase MDCT with pathologic correlation.
    Tsai SD, Kawamoto S, Wolfgang CL, Hruban RH, Fishman EK
    Abdom Imaging. 2015 Jun;40(5):1121-30
  • In conclusion, carcinoid tumors of the duodenum most often present as a focal polypoid mass, but may present as an area of wall thickening or intramural mass with the primary tumor not well defined. Regional lymphadenopathy may be more pronounced than the primary lesion in the duodenum. The CT features of an enhancing duodenal mass can be suggestive of a carcinoid tumor. Duodenal carcinoid tumors are most common in the proximal duodenum and may present with metastatic disease as evidenced by regional enhancing lymphadenopathy or hypervascular liver lesions.
    Duodenal neuroendocrine tumors: retrospective evaluation of CT imaging features and pattern of metastatic disease on dual-phase MDCT with pathologic correlation.
    Tsai SD, Kawamoto S, Wolfgang CL, Hruban RH, Fishman EK
    Abdom Imaging. 2015 Jun;40(5):1121-30
  • “ Patients with metastatic MNETs often die of local complications of the primary tumor, such as small bowel obstruction or ischemia. These complications van potentially be avoided by resection of the primary tumor, with recent literature showing that resection has a survival benefit.”
    Midgut Neuroendocrine Tumors: Imaging Assessment for Surgical Resection
    Woodbridge LR et al.
    RadioGraphics 2014; 34:413-426
  • “ MNETs can release local growth factors and other substances, resulting in extensive mesenteric fibrosis, or desmoplasia. Desmoplasia leads to fixation of the mesentery with multiple fibrous bands and can cause small bowel obstruction and vascular occlusion. Regions of dysplasia should be resected to prevent development of an obstruction in the small bowel. ”
    Midgut Neuroendocrine Tumors: Imaging Assessment for Surgical Resection
    Woodbridge LR et al.
    RadioGraphics 2014; 34:413-426
  • “ The most common clinical signs and symptoms of gastrointestinal neuroendocrine carcinomas are intermittent intestinal obstruction, vague abdominal pain, hematemesis, or hematochezia.”
    CT and enhanced CT in diagnosis of gastrointestinal neuroendocrine carcinomas
    Wang D et al.
    Abdom Imaging (2012); 37:738-745
  • “ Most gastrointestinal neuroendocrine carcinomas are hypervascular and will be best seen in the arterial phase moderately or obviously enhanced. However, in some cases, portal venous phase imaging best demonstrates the tumors.”
    CT and enhanced CT in diagnosis of gastrointestinal meuroendocrine carcinomas
    Wang D et al.
    Abdom Imaging (2012); 37:738-745
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