The case for computed tomographic angiography for initial management of lower gastrointestinal hemorrhage

Lower gastrointestinal hemorrhage remains a common disease, frequently presenting with acute life-threatening symptoms. Although prompt detection and treatment are imperative, it is difficult to diagnose lower gastrointestinal hemorrhage in an accurate and efficient manner. Most available modalities are time consuming. Computed tomographic angiography of the abdomen and pelvis, on the other hand, has the unique capability of rapidly detecting whether life-threatening hemorrhage is occurring and accurately localizing it, thus facilitating definitive treatment. We present a case in which computed tomographic angiography was invaluable in the detection and subsequent empirical transarterial embolization of a lower gastrointestinal hemorrhage and offer evidence as to why it should be a first-line tool in the management of these patients.

Accuracy of 99mTechnetium-labeled RBC Scintigraphy and MDCT With Gastrointestinal Bleed Protocol for Detection and Localization of Source of Acute Lower Gastrointestinal Bleeding

BACKGROUND

Acute lower gastrointestinal bleeding (LGIB) is a major cause of morbidity and mortality. Multidetector row computed tomography (CT) with gastrointestinal (GI) bleed protocol is a novel diagnostic technique for detecting and localizing LGIB. Being rapid and noninvasive, it may be useful as a first-line modality to investigate cases of acute LGIB.

GOALS

To assess and compare diagnostic accuracy of (99M)Technetium (Tc)-labeled red blood cell (RBC) scintigraphy and multidetector row CT with GI bleed protocol for detection and localization of source of acute LGIB.

STUDY

Requirement of informed consent was waived for this retrospective study. Seventy-six patients had undergone either RBC scintigraphy, CT with GI bleed protocol, or both, followed by conventional angiography for evaluation of acute persistent LGIB between January 2010 and February 2014 at our institution. Accuracy of both modalities was assessed using conventional angiography as reference standard and compared using the 2-tailed, Fisher exact test. A P-value of <0.05 was considered statistically significant.

RESULTS

Fifty-one, 20, and 5 patients had undergone RBC scintigraphy only, CT with GI bleed protocol only, and both modalities, respectively. Fourteen of 25 patients in the CT group had angiographic evidence of active bleeding as compared with 32 of 56 patients in the scintigraphy group. CT with GI bleed protocol had higher accuracy (96%) than (99M)Tc-labeled RBC scintigraphy (55.4%, P<0.001).

CONCLUSIONS

CT with GI bleed protocol was more accurate in detecting and localizing the source of acute LGIB as compared with (99M)Tc-labeled RBC scintigraphy.

Gastrointestinal hemorrhage: evaluation with MDCT

Gastrointestinal (GI) bleeding is a common medical problem, with high associated morbidity and mortality. The clinical presentation of gastrointestinal hemorrhage varies with the location of the bleeding source, the intensity of the bleed, and the presence of comorbidities that affect the ability to tolerate blood loss. Conventional endoscopic examinations are usually the initial diagnostic tests in patients presenting with overt gastrointestinal hemorrhage. However, implementation of upper tract endoscopy and colonoscopy in the emergency setting can be challenging due to inconsistent availability of the service and difficulties in achieving adequate colonic cleansing in emergent situations. Thus, imaging tests are often relied upon to establish the location and the cause of bleeding, either for initial diagnosis or after non-revealing upper and lower tract endoscopies ("obscure" bleeding). This article discusses the imaging evaluation of patients with gastrointestinal bleeding and reviews the imaging appearance of the most common causes, taking into account the two most relevant clinical presentations: overt bleeding and obscure bleeding.

Diagnostic Performance of CT Angiography in Patients Visiting Emergency Department with Overt Gastrointestinal Bleeding

Objective

To investigate the diagnostic performance of computed tomography angiography (CTA) in identifying the cause of bleeding and to determine the clinical features associated with a positive test result of CTA in patients visiting emergency department with overt gastrointestinal (GI) bleeding.

Materials and Methods

We included 111 consecutive patients (61 men and 50 women; mean age: 63.4 years; range: 28-89 years) who visited emergency department with overt GI bleeding. They underwent CTA as a first-line diagnostic modality from July through December 2010. Two radiologists retrospectively reviewed the CTA images and determined the presence of any definite or potential bleeding focus by consensus. An independent assessor determined the cause of bleeding based on other diagnostic studies and/or clinical follow-up. The diagnostic performance of CTA and clinical characteristics associated with positive CTA results were analyzed.

Results

To identify a definite or potential bleeding focus, the diagnostic yield of CTA was 61.3% (68 of 111). The overall sensitivity, specificity, positive predictive value (PPV), and negative predictive value were 84.8% (67 of 79), 96.9% (31 of 32), 98.5% (67 of 68), and 72.1% (31 of 43), respectively. Positive CTA results were associated with the presence of massive bleeding (p = 0.001, odds ratio: 11.506).

Conclusion

Computed tomography angiography as a first-line diagnostic modality in patients presenting with overt GI bleeding showed a fairly high accuracy. It could identify definite or potential bleeding focus with a moderate diagnostic yield and a high PPV. CTA is particularly useful in patients with massive bleeding.

Multidetector CT angiography for acute gastrointestinal bleeding: technique and findings

Acute gastrointestinal bleeding is a common reason for emergency department admissions and an important cause of morbidity and mortality. Factors that complicate its clinical management include patient debility due to comorbidities; intermittence of hemorrhage; and multiple sites of simultaneous bleeding. Its management, therefore, must be multidisciplinary and include emergency physicians, gastroenterologists, and surgeons, as well as radiologists for diagnostic imaging and interventional therapy. Upper gastrointestinal tract bleeding is usually managed endoscopically, with radiologic intervention reserved as an alternative to be used if endoscopic therapy fails. Endoscopy is often less successful in the management of acute lower gastrointestinal tract bleeding, where colonoscopy may be more effective. The merits of performing bowel cleansing before colonoscopy in such cases might be offset by the resultant increase in response time and should be weighed carefully against the deficits in visualization and diagnostic accuracy that would result from performing colonoscopy without bowel preparation. In recent years, multidetector computed tomographic (CT) angiography has gained acceptance as a first-line option for the diagnosis and management of lower gastrointestinal tract bleeding. In selected cases of upper gastrointestinal tract bleeding, CT angiography also provides accurate information about the presence or absence of active bleeding, its source, and its cause. This information helps shorten the total diagnostic time and minimizes or eliminates the need for more expensive and more invasive procedures.

A Blood Flow Measurement Robotic System: Ultrasound Visual Servoing Algorithms Under Pulsation and Displacement of an Artery

The purpose of this paper is to propose blood flow measurement algorithms during nonperiodic displacement of an artery by controlling an ultrasound (US) probe. Detecting the position and speed of the bleeding source is required as the first step in treating internal bleeding in emergency medicine. Current methods for detecting a bleeding source, however, involve an invasive approach and cannot quantitatively estimate bleeding speed. Current emergencymedical care therefore requires an alternative system for addressing these problems. In this study, we aim to develop a blood flow measurement system for detecting a bleeding source by using a noninvasive modality, such as a US imaging device. Some problems related to the measurement error still need to be addressed before we can create this system. Specifically, blood flow measurement error in the abdominal area is typically large because the displacement of the artery is large and nonperiodic to adequately control the probe. As the first step in solving these problems, we focused on the displacement of the artery toward the out-ofplane state of the US image and developed measurement algorithms to control the probe, based on respiratory information, during artery displacement. We conducted experimentsmeasuring cross-sectional area and flow rate using an ultrasound phantom containing an artery model and a manipulator equipped with a US probe, BASIS-1. As of this writing, results represent the first experimental validation of the proposed algorithms.

Detection of intestinal bleeding with multi-detector row CT in an experimental setup. How many acquisitions are necessary?

The purpose of the study was to evaluate multi-detector computed tomography (MDCT) acquired in different acquisitions (unenhanced, and arterial and portal venous phase following intravenous contrast medium) for detection of intestinal bleeding using an experimental bowel model. The model consisted of an injector tube with a perforation placed in a 7-m-long small bowel of a pig. The bowel was filled with water/contrast medium solution of 30–40 HU and was incorporated in a phantom model. Intestinal bleeding in different locations and bleeding velocities varying from zero to 0.75 ml/min (0.05 ml/min increments) were simulated. Twenty-six datasets in simulated unenhanced, arterial and portal venous contrast phase using increasing bleeding velocities and ten negative controls were measured using 64-row MDCT. Two radiologists blinded to the experimental settings evaluated the datasets in a random order. The likelihood of intestinal bleeding was assessed using a 5-point scale with subsequent ROC analysis. The overall sensitivity for detecting bleeding was 0.44 for an arterial acquisition alone, 0.68 for a portal venous acquisition, 0.68 for the combination unenhanced/arterial, 0.72 for unenhanced/portal venous and 0.80 for arterial/portal. Bleeding velocities of above 0.25 ml/min were detected with a sensitivity of 0.59 for arterial, 0.88 for portal venous, 0.85 for unenhanced/arterial, 0.94 for unenhanced/portal venous and 0.97 for arterial/portal venous contrast phase protocols, respectively. The specificity was 1.00. MDCT provides the highest sensitivity and specificity in the detection of intestinal bleeding using arterial and portal venous acquisition in comparison to mono-phase protocols.

Prospective blinded comparison of wireless capsule endoscopy and multiphase CT enterography in obscure gastrointestinal bleeding

PURPOSE

To compare the performance of multiphase computed tomographic (CT) enterography with that of capsule endoscopy in a group of patients with obscure gastrointestinal bleeding (OGIB).

MATERIALS AND METHODS

This prospective HIPAA-compliant study was approved by the institutional review board and the institutional conflict of interest committee. All patients provided written informed consent. Two radiologists, blinded to clinical data and results of capsule endoscopy, interpreted images from CT enterography independently, with discordant interpretations resolved by consensus. Results were compared with those from a reference standard (surgery or endoscopy) and clinical follow-up. Sensitivity and 95% confidence intervals were calculated for each modality.

RESULTS

Fifty-eight adult patients, referred for the evaluation of OGIB (occult, 25 patients [43%]; overt, 33 patients [57%]), underwent both tests. A small bowel bleeding source was identified in 16 of the 58 patients (28%). The sensitivity of CT enterography was significantly greater than that of capsule endoscopy (88% [14 of 16 patients] vs 38% [six of 16 patients], respectively; P = .008), largely because it depicted more small bowel masses (100% [nine of nine patients] vs 33% [three of nine patients], respectively; P = .03). No additional small bowel tumors were discovered during the follow-up period (range, 5.6-45.9 months; mean, 16.6 months).

CONCLUSION

In this referral population, the sensitivity of CT enterography for detecting small bowel bleeding sources and small bowel masses was significantly greater than that of capsule endoscopy. On the basis of these findings, the addition of multiphase CT enterography to the routine diagnostic work-up of patients with OGIB should be considered, particularly in patients with negative findings at capsule endoscopy.

[Surgical intervention in acute upper gastrointestinal bleeding]

BACKGROUND AND PURPOSE

Acute gastrointestinal bleeding (AGIB) requiring transfusion and surgical treatment still constitutes a life-threatening situation. The purpose of this paper was to examine the treatment outcome for this group of patients as a function of various risk factors and to present our diagnostic and therapeutic regime.

METHODS

A retrospective analysis of data from 154 patients with AGIB who underwent surgical procedures and received massive transfusions in a university hospital between 1999 and 2008 was carried out.

RESULTS

The patients were divided into two groups. Group I include 91 patients with acute upper gastrointestinal bleeding and group II included 63 patients with lower gastrointestinal bleeding. The average age was 67 years (range 29-93 years) in group I and 70 years (39-97 years) in group II. The initial hemoglobin level was 8.4 g/dl in group I and 10.5 g/dl in group II. Univariate analysis of mortality revealed the following significant risk factors for group I: postoperative need for ventilation (p=0.007), prolonged ICU stay (p=0.004) and anticoagulants in the medical history. The risk factors in group II were blood transfusions >10 units (p=0.031), postoperative need for ventilation (p=0.004), necessary reoperations (p=0.016) and an initial hemoglobin level <8.0 g/dl (p=0.043). The complication rate was 76.9% (mortality rate 34.1%) in group I and 60.3% (mortality rate 15.9%) in group II.

CONCLUSIONS

Examination and stabilization of the patient is directly followed by diagnostic localization. The indication for surgery is mainly limited to peracute, uncontrollable and recurrent forms of gastrointestinal bleeding. The mortality rate for these critically ill, negatively selected patients remains high and could not be lowered in the last decade. Postoperative need of ventilation is a predictor for poor prognosis.

Volcano-like intermittent bleeding activity for seven years from an arterio-enteric fistula on a kidney graft site after pancreas-kidney transplantation: a case report

Introduction

We report the first case of a patient who underwent simultaneous kidney and pancreas transplantation and who then suffered from repeated episodes of severe gastrointestinal bleeding over a period of seven years. Locating the site of gastrointestinal bleeding is a challenging task. This case illustrates that detection of an arterio-enteric fistula can be very difficult, especially in technically-challenging situations such as cases of severe intra-abdominal adhesions. It is important to consider the possibility of arterio-enteric fistulas in cases of intermittent bleeding episodes, especially in transplant patients.

Case presentation

A 40-year-old Caucasian man received a combined pancreas-kidney transplantation as a result of complications from diabetes mellitus type I. Thereafter, he suffered from intermittent clinically-relevant episodes of gastrointestinal bleeding. Repeat endoscopic, surgical, scintigraphic, and angiographic investigations during his episodes of acute bleeding could not locate the bleeding site. He finally died in hemorrhagic shock due to arterio-enteric bleeding at the kidney graft site, which was diagnosed post-mortem.

Conclusions

In accordance with the literature, we suggest considering the removal of any rejected transplant organs in situations where arterio-enteric fistulas seem likely but cannot be excluded by repeat conventional or computed tomography-angiographic methods. Arterio-enteric fistulas may intermittently bleed over many years.

Multi-phase CT enterography in obscure GI bleeding

Multiphase CT enterography is a modification of conventional abdominal CT designed to optimize detection of abnormalities responsible for obscure GI bleeding. This imaging test appears to be complimentary to wireless capsule endoscopy in the evaluation of this difficult group of patients. A description of exam technique, findings, and discussion of results will be presented in this article.

Investigation of acute lower gastrointestinal bleeding with 16- and 64-slice multidetector CT

We evaluated the usefulness of 16- and 64-slice multidetector CT (MDCT) in the detection of a bleeding site in acute lower gastrointestinal tract (GIT) haemorrhage by conducting a retrospective study of cases of presumed acute lower GIT haemorrhage imaged with CT in two teaching hospitals in an 11-month period. The patients underwent contrast enhanced CT using either a 16 or 64 MDCT. No oral contrast was used. One hundred milliliters of non-ionic intravenous contrast agent was injected at 4.5 mL/s, followed by a 60 mL saline flush at 4 mL/s through a dual head injector. Images were acquired in arterial phase with or without non-contrast and portal phase imaging with 16 x 1.5 mm or 64 x 0.625 mm collimation. Active bleeding was diagnosed by the presence of iodinated contrast extravasation into the bowel lumen on arterial phase images with attenuation greater than and distinct from the normal mucosal enhancement or focal pooling of increased attenuation contrast material within a bowel segment on portal-venous images. Further management and final diagnosis was recorded. Fourteen patients and 15 studies were reviewed. CT detected and localized a presumed bleeding site or potential causative pathology in 12 (80%) of the patients. Seven of these were supported by other investigations or surgery, while five were not demonstrated by other modalities. Eight patients had mesenteric angiography, of which only four corroborated the site of bleeding. CT did not detect the bleeding site in three patients, of which two required further investigation and definitive treatment. We propose that MDCT serves a useful role as the initial rapid investigation to triage patients presenting with lower GIT bleeding for further investigation and management.

Surgical treatment concepts for acute lower gastrointestinal bleeding

BACKGROUND AND PURPOSE

To this day, the diagnostic and therapeutic strategy for acute lower gastrointestinal hemorrhage requiring transfusion varies among different hospitals. The purpose of this paper was to evaluate our own data on the group of patients presented and to outline our diagnostic and therapeutic regime taking into account the literature of the past 30 years.

METHODS

Following prospective data collection on 63 patients of a university hospital (40 male, 23 female patients) who received surgical intervention for acute lower intestinal hemorrhage requiring transfusion, we retrospectively analyzed the data. After a medical history had been taken, all patients underwent clinical examination, including digital palpation; 62 patients underwent procto-rectoscopy, 38 gastroscopy and colonoscopy, 52 patients colonoscopy only, and 45 patients gastroscopy only. Angiography was applied in 14 cases and scintigraphy in 20 cases.

RESULTS

Diagnostic procedures to localize hemorrhage were successful in 61 cases, 41 of which through endoscopy, 12 through angiography, and eight through scintigraphy. Of our group of patients, 32 suffered from a bleeding colonic diverticulum, eight from angiodysplasia, and five from bleeding small bowel diverticula. Five patients had inflammatory bowel disease and three neoplasia. Among the surgical interventions, segmental resections were performed most frequently (15 sigmoidectomies, 11 small bowel segmental resections, 11 left hemicolectomies, seven right hemicolectomies, one proctectomy). Subtotal colectomies were carried out in ten cases. The complication rate for this group of critically ill, negatively selected patients was 60.3% and the mortality rate was 15.9%.

CONCLUSIONS

Examination and stabilization of the patient is directly followed by diagnostic localization. Today, we primarily rely on nonsurgical control of hemorrhage by endoscopy or angiography; the indication for surgery is mainly limited to peracute, uncontrollable, and recurrent forms. In the case of surgery, intestinal segmental resection is recommended after identification of the lesion; if the localization of colonic hemorrhage is uncertain, subtotal resection is the method of choice. For stable patients with unverifiable small-bowel hemorrhage we recommend regular re-evaluation.

Evaluation of dual-phase multi-detector-row CT for detection of intestinal bleeding using an experimental bowel model

To evaluate dual-phase multi-detector-row computed tomography (MDCT) in the detection of intestinal bleeding using an experimental bowel model and varying bleeding velocities. The model consisted of a high pressure injector tube with a single perforation (1 mm) placed in 10-m-long small bowel of a pig. The bowel was filled with water/contrast solution of 30-40 HU and was incorporated in a phantom model containing vegetable oil to simulate mesenteric fat. Intestinal bleeding in different locations and bleeding velocities varying from zero to 1 ml/min (0.05 ml/min increments, constant bleeding duration of 20 s) was simulated. Nineteen complete datasets in arterial and portal-venous phase using increasing bleeding velocities, and seven negative controls were measured using a 64 MDCT (3-mm slice thickness, 1.5-mm reconstruction increment). Three radiologists blinded to the experimental settings evaluated the datasets in a random order. The likelihood for intestinal bleeding was assessed using a 5-point scale with subsequent ROC analysis. The sensitivity to detect bleeding was 0.44 for a bleeding velocity of 0.10-0.50 ml/min and 0.97 for 0.55-1.00 ml/min. The specificity was 1.00. The area under the curve was calculated to be 0.73, 0.88 and 0.89 for reader 1, 2 and 3, respectively. Dual-phase MDCT provides high sensitivity and specificity in the detection of intestinal bleeding with bleeding velocities of 0.5-1.0 ml/min. Therefore, MDCT should be considered as a primary diagnostic technique in the management of patients with suspected intestinal bleeding.

Obscure gastrointestinal bleeding: evaluation with 64-section multiphase CT enterography--initial experience

This retrospective HIPAA-compliant study was approved by the institutional review board and institutional conflict of interest committee. Patients gave informed consent for use of medical records. The purpose of the study was to retrospectively evaluate the findings depicted at computed tomographic (CT) enterography performed with a 64-section CT system and by using neutral enteric contrast material and a three-phase acquisition in patients with obscure gastrointestinal bleeding (OGIB). Twenty-two outpatients (11 men, 11 women; age range, 37-83 years) with OGIB underwent CT enterography. Findings were compared with capsule and traditional endoscopic, surgical, and angiographic findings. CT enterographic findings were positive for a bleeding source in 10 (45%) of 22 patients. Eight of 10 positive findings at CT enterography were also positive at capsule endoscopy or subsequent clinical diagnosis. CT enterography helped correctly identify three lesions undetected at capsule endoscopy. Study results suggest that multiphase, multiplanar CT enterography may have a role in the evaluation of OGIB.