**5.3 DAE**

DAE includes balloon-assisted enteroscopy (single balloon and double balloon) and spiral enteroscopy.

Single-balloon enteroscopy (SBE) and double-balloon enteroscopy (DBE) were developed in 2006 and 2001, respectively, to examine the entire small bowel mucosa. Both procedures are bidirectional, i.e., the enteroscope is introduced anterogradely through the mouth and retrogradely through the anus, and the midway point is marked by tattooing or endoclipping [27]. Although the rate of complete visualization of the small bowel is three times (66 vs. 22%) higher with DBE than that with SBE [28], the diagnostic and therapeutic yields of these two procedures do not differ significantly [29]. In spiral enteroscopy (SE), the small bowel is pleated on the enteroscope by a screw operated by a machine, and the rotational force is converted into a linear force. In one study, complete enteroscopy was successful in 92% of cases of bidirectional DBE and 8% of cases of SE, although the diagnostic and therapeutic outcomes were not statistically different [30].

### **5.4 CTE**

CTE is a useful tool in the evaluation of mid-GI bleed due to vascular lesion. Characteristic enhancement of the vascular lesion can be seen [31]. They are classified as angioectasia, arterial lesions (Dieulafoy's lesion and arteriovenous malformation), and venous lesions (vascular lesion with unusual morphology). Active bleeding is evidenced by progressive accumulation of contrast material over the three phases on the dependent surface of the intestine or distributed over a wide area by peristalsis. CT enterography is also useful in the detection of inflammatory and neoplastic condition of the small bowel [32].

#### **5.5 MRE**

MRE is a noninvasive radiation-free method of evaluating the entire small bowel. It can detect the mural thickening (>4 mm) and mass lesion of the small bowel. These lesions could be secondary to inflammatory and benign conditions (like Crohn's disease, adenoma, lipoma, fibroepithelial polyps) or malignant conditions (like neuroendocrine tumors, GIST, adenocarcinoma, lymphoma, and Peutz-Jeghers syndrome) [33, 34].

#### **5.6 Bleeding scan**

Bleeding scan is a nuclear medicine test performed by injecting 99 m technetium-labeled red blood cells (RBC). It can detect extravasation of tagged RBC if the bleeding rate is 0.1 ml/minute or more. It is a highly sensitive test in detecting active bleeding in the gastrointestinal tract and can localize the site of bleeding accurately in 52% of cases [35].

#### **5.7 Meckel's scan**

Meckel's scan is also a nuclear medicine test performed by injecting 99 m technetium pertechnetate which has affinity for the gastric mucosa. It is positive in

**27**

cases.

**6. Management**

peutic purposes [40].

*Mid-Gastrointestinal Bleeding*

**5.8 CT angiography (CTA)**

avoid CTA.

*DOI: http://dx.doi.org/10.5772/intechopen.89337*

**5.9 Conventional mesenteric angiography (CMA)**

**5.10 Gallium-68 dotatate PET/CT scan**

**5.11 Intraoperative enteroscopy**

patients with Meckel's diverticulum with heterotopic/ectopic gastric mucosa. Acid secretion from the gastric mucosa can cause ulceration and bleeding near or adjacent to the diverticulum. In children, Meckel's scan is performed early, whereas in

CTA is increasingly being done in patients with less brisk mid-GI bleeding. CTA can detect the bleeding site if the bleeding rate is 0.3 ml/minute or more [36]. However, CTA exposes the patient to ionizing radiation, and intravenous contrast is required. So patients with contrast allergy, renal failure, and pregnancy should

CMA is rarely done in the evaluation of mid-GI bleeding unless there is ongoing significant bleeding and patient had hemodynamic instability, positive CTE, or bleeding scan; and embolization is considered to stop the bleeding. However, there is risk of bowel wall infarction following embolization therapy. CMA can also detect small bowel varices in patients with portal hypertension and Meckel's diverticulum by the finding of an anomalous long branch of superior mesenteric artery traversing the mesentery toward the right lower quadrant and supplying the diverticulum.

Gallium-68 dotatate PET/CT scan is now considered as the best scan for detecting SBNET as 70–90% of them have somatostatin receptors. It has much better imaging quality and can detect more lesions than Octreoscan [37]. But it does not replace CTE or MRE for those SBNET which are not somatostatin receptor positive.

Intraoperative enteroscopy is done in the operating room when other modalities of investigations fail to detect the source of bleeding. The scope is introduced through the mouth or through an enterotomy, and whole small bowel can be evaluated. It is diagnostic as well as therapeutic in achieving hemostasis in about 70% of

A systematic approach is essential to manage mid-GI successfully. Mid-GI bleeding is generally established when no source of potential bleeding is found in the upper or lower gastrointestinal tract after doing bidirectional endoscopy, i.e., upper endoscopy (including examination with a side-viewing duodenoscope) and ileocolonoscopy. Second-look bidirectional endoscopy should be done considering substantial initial endoscopic miss rates [38]. Next step to evaluate is whether the patient is hemodynamically stable or unstable and whether the patient is having occult or overt GI bleeding. The first investigation to evaluate mid-GI bleeding in a hemodynamically stable patient is VCE unless there are contraindications like small bowel obstruction [39]. On the other hand, in a hemodynamically unstable patient, the first investigation will be angiography for both diagnostic and thera-

adults, it is generally performed late in the evaluation of mid-GI bleeding.

#### *Mid-Gastrointestinal Bleeding DOI: http://dx.doi.org/10.5772/intechopen.89337*

patients with Meckel's diverticulum with heterotopic/ectopic gastric mucosa. Acid secretion from the gastric mucosa can cause ulceration and bleeding near or adjacent to the diverticulum. In children, Meckel's scan is performed early, whereas in adults, it is generally performed late in the evaluation of mid-GI bleeding.
