What are the indications for a small bowel follow-through in patients with suspected small bowel disease, including those with abdominal pain, diarrhea, weight loss, or bleeding, and a history of abdominal surgery, gastrointestinal disorders, or radiation therapy?

Small Bowel Follow-Through Indications

Small bowel follow-through (SBFT) has been largely superseded by capsule endoscopy and cross-sectional imaging (CT/MR enterography) for most small bowel evaluations and should generally not be used as a first-line diagnostic modality for suspected Crohn's disease or obscure gastrointestinal bleeding. 1

Current Role of SBFT in Clinical Practice

Limited Diagnostic Utility

• SBFT has significantly lower diagnostic yield compared to modern imaging modalities, detecting inflammatory lesions in only 24-57% of cases versus 71-97% with capsule endoscopy combined with ileocolonoscopy 2, 3
• The two-dimensional perspective of SBFT results in pathology being obscured by overlapping bowel loops, limiting its accuracy for detecting active disease 1
• SBFT failed to make any independent diagnoses in one prospective study where all diagnoses required confirmation by other modalities 2

Remaining Clinical Applications

Water-Soluble Contrast Challenge (Modified SBFT Protocol)

• The primary remaining indication for SBFT is as a water-soluble contrast challenge to predict success of conservative management in small bowel obstruction 1
• This "abbreviated" protocol involves administering 100 mL of hyperosmolar iodinated contrast (such as diatrizoate) with follow-up radiographs at 8 and 24 hours 1
• Patients in whom contrast reaches the colon by 24 hours rarely require surgery, making this a useful triage tool 1
• This approach significantly reduces time to both operative intervention (1.0 vs 3.7 days) and nonoperative resolution (1.8 vs 4.7 days) compared to management without SBFT 4

Preoperative Anatomic Delineation

• SBFT may have a limited role in delineating preoperative anatomy for surgeons, depending on institutional preference, though this use has markedly declined 1
• The real-time assessment of bowel pliability versus fixed stenosis can provide ancillary information not available from cross-sectional imaging 1

Detection of Internal Fistulas

• SBFT can detect internal fistulas in Crohn's disease, though it poorly visualizes extramural complications like abscesses 1

Preferred Alternative Modalities

For Suspected Crohn's Disease

• Capsule endoscopy should be the initial small bowel imaging modality when ileocolonoscopy is negative and there are no obstructive symptoms or known stenosis 1
• Capsule endoscopy has superior diagnostic yield compared to SBFT (96% vs 67%) and detects significantly more inflammatory lesions 5, 2
• MR enterography or CT enterography should be used instead of SBFT when obstructive features or known stenosis are present 1

For Obscure Gastrointestinal Bleeding

• Capsule endoscopy is strongly recommended as the next diagnostic step after negative EGD and colonoscopy, ideally performed as soon as possible 1, 6
• SBFT has no role in the evaluation of obscure GI bleeding 1

For Established Crohn's Disease

• Cross-sectional imaging with MRE or CTE is preferable to SBFT because these modalities can identify obstructive strictures, assess transmural disease extent, and detect extramural complications 1
• SBFT cannot adequately assess the transmural nature of disease or extraluminal complications 1

Critical Contraindications and Pitfalls

Absolute Contraindications

• Barium-based SBFT is contraindicated in suspected or confirmed bowel perforation due to risk of severe chemical peritonitis 7
• SBFT should not be performed when high-grade obstruction is suspected, as it provides inadequate information for surgical decision-making 1

Common Pitfalls

• SBFT has poor specificity for Crohn's disease, as small lesions may represent NSAID-induced enteropathy, vasculitis, or other conditions 1
• SBFT failed to detect a stricture in one study, resulting in capsule retention requiring surgical removal 3
• The diagnostic yield of SBFT is particularly poor in patients with only abdominal pain or diarrhea without inflammatory biomarkers 1

When SBFT Might Still Be Considered

SBFT may be acceptable in resource-limited settings where:

• Cross-sectional imaging and capsule endoscopy are unavailable 1
• Water-soluble contrast challenge is needed for small bowel obstruction management 1, 4
• Real-time fluoroscopic assessment of bowel pliability is specifically requested by the surgical team 1

However, clinicians should recognize that SBFT has been replaced by superior modalities in contemporary practice, with capsule endoscopy and MR/CT enterography offering higher diagnostic accuracy, better visualization of mucosal disease, and ability to detect extraluminal complications 1, 2.