The use of MRI to demonstrate small bowel obstruction during pregnancy

Intestinal obstruction is a rare but serious complication of pregnancy with significant maternal and fetal mortality. The reported incidence of intestinal obstruction complicating pregnancy varies widely, from 1 in 66,431 to 1 in 1,500 deliveries. A retrospective review of 66 cases of intestinal obstruction complicating pregnancy and the puerperium, including 2 cases from our institution, revealed that the most common causes of mechanical obstruction were adhesions (58%), volvulus (24%), and intussusception (5%). Seventy-seven percent of the patients with obstruction due to adhesions had undergone previous abdominal or pelvic surgery. Presenting symptoms and signs were similar to those of the nonpregnant patient; abdominal pain was present in 98% of patients, vomiting in 82%, and tenderness to palpation in 71%. In 82% of patients, obstruction was evident on radiographic evaluation. Prompt management of obstruction is essential; the median length of time from admission to laparotomy in the 66 patients was 48 hours. Bowel strangulation requiring resection was present in 23% of patients. Thirty-eight percent of patients completed term pregnancies after operative resolution of obstruction; total maternal mortality was 6%, and total fetal mortality 26%. Thus, both mother and fetus are at risk when intestinal obstruction complicates pregnancy. Clinical suspicion of the presence of obstruction and aggressive intervention are required to decrease the morbidity and mortality of this rare complication of pregnancy.

Conventional enteroclysis remains the method of choice in the diagnosis of inflammatory small bowel disease. The reported sensitivity rates, however, for the diagnosis of extraintestinal processes, such as fistulae and abscesses, are moderate. Computed tomography (CT) is the method of choice for the diagnosis of extraintestinal complications. The anatomical designation of the affected bowel segment may, however, prove difficult due to axial slices, and the applied radiation dose is high. The use of magnetic resonance imaging (MRI) in the diagnosis of inflammatory small bowel disease is a relatively new indication for the method; prerequisites were the development of breathhold sequences and phased array coils. Optimized magnetic resonance tomographic imaging requires a combined method of enteroclysis and MRI, which guarantees an optimal filling and distension of the small bowel. The high filling volume leads to a secondary paralysis of the small bowel and avoids motion artifacts. In a trial of 84 patients with histological and endoscopic correlation the sensitivity in diagnosing inflammatory bowel disease was 85.4% for enteroclysis and 95.2% for MRI, and the specificity was 76.9% for enteroclysis and 92.6% for MRI. As none of the abscesses was diagnosed with enteroclysis, the sensitivity was 0% for enteroclysis, but 77.8% for MRI. The sensitivity in diagnosing fistulae was 17.7% for enteroclysis and 70.6% for MRI. In summary, MRI can detect the most relevant findings in patients with inflammatory small bowel disease with an accuracy superior to that of enteroclysis.

The surge in the development of fast magnetic resonance (MR) techniques has revolutionized our ability to image the pregnant patient and the fetus. Fast MR imaging techniques provide excellent resolution for imaging the maternal and fetal anatomies without the need for sedation. This article addresses the use of fast MR imaging techniques in the evaluation of the pregnant patient for adnexal masses, pelvimetry, hydroureteronephrosis of pregnancy, and placenta accreta. In addition, fetal anomalies for which MR imaging has proved useful, such as ventriculomegaly, arachnoid cysts, and abdominal masses, are described.