Diagnostic Yield of Dual-phase Computed Tomography Enterography in Patients With Obscure Gastrointestinal Bleeding and a Non-diagnostic Capsule Endoscopy

Jaya R Agrawal; Anne C Travis; Koenraad J Mortele; Stuart G Silverman; Rie Maurer; Sarathchandra I Reddy; John R Saltzman


J Gastroenterol Hepatol. 2012;27(4):751-759. 

In This Article


Patient Population and Study Schema

There were 57 patients who met the inclusion criteria (Fig. 1), of whom 52 were enrolled in the study (three refused and two were unable to give consent). There was a female predominance of 63% (33/52). The majority of patients were over the age of 40 years (49/52). The bleeding was occult in 26/52 patients (50%) and overt in 26/52 patients (50%). Of the patients with occult bleeding, 14/26 (54%) were both heme-positive and iron-deficient, 10/26 (38%) were either heme-positive or iron-deficient but not both, and 2/26 (8%) had unexplained normocytic anemia, without documented evidence of heme-positivity or iron deficiency. Of the patients with overt bleeding, 16/26 (62%) presented with prior bleeding and 10/26 (38%) presented with active bleeding (all hospitalized patients).

Figure 1.

Study schema. Fifty-two patients were enrolled in the study. Four patients had capsule findings interpreted as a definitive source of bleeding. Forty-eight patients were considered for dual-phase computed tomography enterography (CTE); 25 underwent CTE. CTE identified lesions believed to be the source of bleeding in seven patients.

Diagnostic Yield of Capsule Endoscopy

The overall diagnostic yield of capsule endoscopy was 48% (25/52 patients). Positive sources of bleeding were found in 10/52 patients (19%). Definitive sources of GI bleeding were found in four patients; two of these patients had large jejunal angioectasias and two had ulcers (jejunal and gastric). In the remaining six patients, blood obscured the underlying lesion (and thus these patients were eligible for CTE). Possible sources of bleeding were seen in 15/52 patients (29%). Small bowel angioectasias (some with concurrent gastric antral vascular ectasia) were found in 12 patients, and three showed erosive gastropathies. No identifiable source of bleeding was found in 27/52 patients (52%). Overall, 48/52 patients were eligible for a CTE due to a negative capsule (n = 27), a capsule with a "possible" but not definitive source of bleeding (n = 15), or a capsule with active bleeding where the underlying lesion was obscured by blood (n = 6).

The diagnostic yields of capsule endoscopy were 38% (10/26 patients), 50% (6/16 patients), and 70% (7/10 patients), for patients with occult, prior overt, or active obscure bleeding, respectively (P = 0.21). Of note, in patients with occult bleeding who were both heme-positive and iron-deficient, the diagnostic yield of capsule endoscopy was 71% (10/14), whereas it was 0% (0/12) in those who did not meet both criteria (P < 0.0001).

Diagnostic Yield of CTE

Of the 48 patients eligible for CTE based upon their capsule endoscopy results, 25 underwent the examination (13 were excluded for renal insufficiency, three were excluded for contrast allergy, four refused CTE testing, two had their symptoms resolve spontaneously, and one patient was lost to follow up).

The overall diagnostic yield for CTE in all patients who underwent CTE for a non-diagnostic capsule was 28% (7/25 patients). Using clinical follow up as the gold standard, for the 25 patients with a non-diagnostic capsule, CTE had a sensitivity of 33% (95% confidence interval [CI] 0.15, 0.56) and a specificity of 75% (95%CI 0.22, 0.99). Analyzing the results by clinical presentation, CTE yielded a diagnosis in 0/11 patients (0%) with occult bleeding and in 7/14 patients (50%) with overt (prior and active) bleeding (P < 0.01). The yield of CTE was 3/9 (33%) in patients with prior bleeding and 4/5 (80%) in patients with active bleeding (Fig. 2). Four of six patients with active bleeding seen on capsule endoscopy, where the underlying lesion was obscured by blood, underwent CTE; the CTE was positive in two (50%).

Figure 2.

Diagnostic yield of computed tomography enterography (CTE) in patients with a non-diagnostic capsule endoscopy. Diagnostic yield of dual-phase CTE in patients presenting with occult, prior overt, and active overt bleeding, respectively. The differences in diagnostic yield among the three categories were statistically significant (P < 0.01). , Occult bleeding; , Prior overt bleeding; , Active overt bleeding.

The true positive CTE findings included an ulcer in the terminal ileum (one patient with no findings on capsule, Fig. 3), jejunal angioectasias (one patient with a positive capsule endoscopy but the lesion was obscured by blood, Fig. 4), a Meckel's diverticulum (one patient with a positive capsule endoscopy but the lesion was obscured by blood), portal hypertension (three patients with previously undiagnosed cirrhosis, including one with esophageal varices, one with gastric varices, and one with portal hypertensive gastropathy, two of whom had "possible" findings of gastric erosions and small bowel angioectasia and the third had no findings), and an enhancing mass and layering of blood in the terminal ileum, later documented to be metastatic melanoma (one patient with no findings on capsule endoscopy). All lesions were seen in both the arterial and enteric phases. In the case of the jejunal angioectasias, one lesion appeared to expand on the 70-s delayed enteric phase, suggesting active bleeding.

Figure 3.

Terminal ileum ulcer on computed tomography enterography (CTE). Dual-phase CTE shows hyper-enhancement of a soft tissue lesion in the terminal ileum (arrow) in a patient presenting with intermittent melena and no findings on capsule endoscopy. This lesion was found to be a terminal ileum ulcer on repeat colonoscopy with ileal intubation to 10 cm; symptoms resolved after endoscopic treatment.

Figure 4.

Jejunal angioectasias on computed tomography enterography (CTE). Dual-phase CTE showing hyperenhancing lesions (arrows) in the mucosa of the jejunum, suggesting angioectasias.

The diagnostic evaluation in patients with a positive CTE examination is summarized in Table 1. Of note, in three of the seven patients with diagnostic (true positive) CTE (ileal ulcer, ileal mass, gastric varices), the capsule endoscopy yielded no findings. In two of these patients, the CTE identified the underlying bleeding lesion where the capsule endoscopy visualized only blood (Meckel's, small bowel angioectasias [AVM]). In a third patient, the CTE confirmed the source suggested by capsule endoscopy (portal hypertensive gastropathy). In another patient, the CTE showed cirrhosis and esophageal varices in a patient in whom the presumed source of bleeding based on capsule endoscopy was jejunal AVM. In this case, the final diagnosis was that of the CTE (varices). In one additional patient, the CTE showed diffuse, left-sided colonic enhancement, more pronounced during the enteric phase. Repeat colonoscopy with biopsy was negative, and therefore this result was felt to be a false positive CTE.

The diagnostic evaluation in patients with a non-diagnostic CTE examination is summarized in Table 2. Of the 17 negative examinations (Table 2), three had spontaneous resolution of symptoms on follow up. The clinician following the patients determined that most likely these results represent true negative CTE, where no bleeding lesions were present at the time of the examination. The remaining 14 patients had false negative examinations. In five patients, the final diagnosis recorded by the physician after follow-up testing was the result of prior capsule endoscopy which was initially read as a possible source. These included a jejunal AVM, a gastric ulcer, two ileal AVM, and enteritis. In the remaining nine patients, both the capsule endoscopy and CTE yielded no findings suggestive of a bleeding source. In five of these patients no source was ever found, though symptoms persisted or chronic iron replacement was required to treat recurrent anemia. In the other four patients, follow-up testing yielded final diagnoses of AVM (n = 2), celiac disease (n = 1), and Meckel's diverticulum (n = 1).

Of the seven diagnostic CT enterographies, three showed findings related to portal hypertension and the patients were treated with beta blockers; in one, anemia resolved completely. The remaining four patients proceeded to therapeutic procedures based upon the CTE results. The patient with a Meckel's diverticulum underwent surgery with cessation of bleeding. The patient with a terminal ileum ulcer underwent colonoscopy with successful endoscopic control of bleeding and no persistent symptoms. The patient with a mass bleeding into the terminal ileum underwent selective right colic artery embolization with control of bleeding. This patient was discharged to hospice so persistence of anemia could not be evaluated. The final patient with jejunal angioectasias underwent double balloon enteroscopy; however, overt bleeding had resolved prior to this procedure and the jejunal lesions were not visualized during the examination (though smaller AVM of upper small bowel were treated); anemia persisted in this patient.

Incidental findings on CTE that required follow-up testing were found in 5/25 patients (20%) who underwent CTE. The findings included an adrenal mass requiring follow-up CT, an ovarian cyst requiring follow-up ultrasound, fatty liver requiring liver blood tests and clinical follow up, enlarged lymph nodes requiring follow-up CT, and bony sclerosis requiring follow-up bone scan. The results of the subsequent testing were all either normal or benign.


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