Bạn đang ở trang: HomeNghiên cứuNghiên cứu của các tác giả khácAcute Massive Gastrointestinal Bleeding: Detection and Localization with Arterial Phase Multi–Detector Row Helical CT

Acute Massive Gastrointestinal Bleeding: Detection and Localization with Arterial Phase Multi–Detector Row Helical CT Featured

To prospectively evaluate accuracy of arterial phase multi– detector row helical computed tomography (CT) for detection and localization of acute massive gastrointestinal (GI) bleeding, with angiography as reference standard.

Materials and Methods:

Institutional review board approved this study; written informed consent was obtained from each patient or patient’s family after procedures, including radiation dose, were explained. Twenty-six consecutive patients (17 men, nine women; age range, 18 – 89 years) had acute massive GI bleeding (defined as requirement of transfusion of at least 4 units of blood during 24 hours in the hospital or as hypotension with systolic blood pressure 90 mm Hg) and underwent arterial phase multi– detector row computed tomography before angiography. Scans were obtained during arterial phase to identify extravasation of contrast material with attenuation greater than 90 HU within bowel lumen; this finding was considered diagnostic for active GI bleeding. Presence of contrast medium extravasation in each anatomic location was recorded. Sensitivity, specificity, positive and negative predictive values, and accuracy of multi– detector row computed tomography for detection of acute GI bleeding were assessed. Accuracy for localization of acute GI bleeding was assessed by comparing locations of active bleeding at both multi– detector row computed tomography and angiography in each patient who had active bleeding.

Results

Arterial phase multi– detector row CT depicted extravasation of contrast material in 21 of 26 patients. Overall location-based sensitivity, specificity, accuracy, and positive and negative predictive values of multi– detector row CT for detection of GI bleeding were 90.9% (20 of 22), 99% (107 of 108), 97.6% (127 of 130), 95% (20 of 21), and 98% (107 of 109), respectively. Overall patient-based accuracy of multi– detector row CT for detection of acute GI bleeding was 88.5% (23 of 26). The location of contrast material extravasation on multi– detector row CT scans corresponded exactly to that of active bleeding on angiograms in all patients with contrast medium extravasation at both multi– detector row CT and angiography.

Conclusion

Arterial phase multi– detector row CT is accurate for detection and localization of bleeding sites in patients with acute massive GI bleeding

(Woong Yoon et al; Radiology: Volume 239: Number 1—April 2006)

Despite advances in medical management, acute gastrointestinal (GI) bleeding remains a major cause of morbidity and mortality. The mortality rate for patients with acute GI bleeding has not changed during the past decade and ranges from 8% to 14% (1–3). Mortality increases to 21%– 40% in cases of massive bleeding associated with hemodynamic instability or in cases in which transfusion of more than 4 units of packed red blood cells is required (4,5). Endoscopy is considered a primary diagnostic modality in patients with acute upper GI tract bleeding. Endoscopy of the upper GI tract, however, often fails to depict the exact focus of bleeding when massive bleeding (1 mL/min) occurs. Vreeburg et al (6) reported that no diagnosis could be made at first endoscopy in 24% of patients with acute upper GI tract bleeding. In their study, excessive blood or clots in the gastroduodenal tract impaired endoscopic view in 15% of patients. There is considerable controversy in regard to the best modality for initial diagnosis of acute lower GI tract bleeding. Diagnostic procedures for lower GI tract bleeding include colonoscopy, technetium 99m (99mTc)–red blood cell scintigraphy, mesenteric angiography, and combinations of these. Although colonoscopy is becoming the most frequently used examination for patients with lower GI tract bleeding, its usefulness for the diagnosis of acute massive bleeding is still controversial. It is generally believed that colonoscopy is usually appropriate when bleeding has stopped spontaneously and bowel preparation is possible (7). Although nuclear scintigraphy is simple to perform, noninvasive, and sensitive, it is time consuming and has limited ability for localization of sites of bleeding. Its high rates of false localization have led most clinicians to perform other diagnostic tests for confirmation of the site of bleeding (7). Some authors believe that mesenteric angiography is the most accurate modality for the diagnosis of acute lower GI tract bleeding (8). Rates of detection of bleeding sites with angiography have been reported to be 58%– 86% (9). The major drawback of angiography is that its rate of detection is influenced by several factors, including the rate of bleeding at the time of angiography and the timing of angiography. Sites of bleeding cannot be demonstrated with angiography even in patients with massive GI bleeding because of its intermittent nature (10). The use of contrast material– enhanced CT in the diagnosis of acute GI bleeding has received little attention. The capability of contrast-enhanced CT to depict acute GI bleeding has been documented only in case reports and a few retrospective series (11–14). Recently, multi– detector row helical CT has increasingly been used in the diagnostic evaluation of most vascular diseases (15). Compared with single– detector row helical CT, multi– detector row CT features strikingly increased image resolution and markedly decreased scanning time. These attributes enable acquisition of accurate arterial phase images and, thus, identification of extravasation of contrast material into the intestinal lumen, a finding diagnostic of acute GI bleeding, before the contrast material is diluted. We hypothesized that active extravasation of contrast material would be identifiable on arterial phase contrast-enhanced multi– detector row CT scans in patients with acute massive GI bleeding and that such identification would enable precise localization of sites of bleeding. Thus, the purpose of our study was to prospectively evaluate the accuracy of arterial phase multi– detector row CT for the depiction and localization of acute massive GI bleeding, with angiography as the reference standard.

More and dowload fulltex here

Rate this item
(0 votes)

Mẹo vặt cuộc sống

Đọc tiếp

Tư vấn

Bệnh trẻ em