Sanjaya Viswamitra MD, Abstract Co-Author: Nothing to Disclose

Shaheen Mithani Hussaini MD, Presenter: Nothing to Disclose

Evaluate the accuracy of MRI in diagnosis of the cause of acute abdomen in pregnant patients.

32 consecutive pregnant patients with acute abdominal pain were imaged with MRI. The initial clinical diagnosis included appendicitis (20), obstructive uropathy (5), pelvic pain (1), trauma (3), venous thrombosis (2), and biliary obstruction (1). All patients were imaged on a 1.5T MRI. MRI protocols included 2D T2W coronal and axial (5-6mm), 2D fat sat T2 axial, 3D and T1W axial images (5-6mm) series. 3D navigator (1.5mm) was performed in 21 patients with TRUFISP bright blood in 10 patients. Image analysis: The visibility and size of the appendix, hydronephrosis and presence of free fluid was evaluated on T2W sequences in all patients. The MRI diagnosis was also correlated with discharge notes, lab values, operative, and pathology reports. We report the accuracy of the MRI exam for the respective diagnoses.

The appendix was seen in 26 patients (81%). Appendicitis was diagnosed with 100% accuracy in 3 patients and excluded in 17 patients. This was based on inflammatory changes and/or an enlarged (>= 7mm) abnormal appendix when seen. Hydronephrosis and perinephric changes diagnosed obstructive uropathy. 4 patients with obstructive uropathy were diagnosed with 100% accuracy. The stone was not visualized in any. 1 patient with pelvic pain had a hemorrhagic cyst on pathology characterized as a complex cyst by MRI. 3 patients screened for intra abdominal trauma after MVA were discharged home based on absence of T2W fluid abnormality on MRI and resolution of clinical symptoms. No contrast was given. 1 patient had cystic duct obstruction in the presence of normal gallbladder ultrasound. Of 2 patients referred for venous thrombosis, 1 with portal vein thrombosis and 1 without splenic vein thrombus were diagnosed on bright blood sequences.

MRI was 100% accurate in the evaluation of abdominal pain in pregnant patients for a variety of indications even when the appendix and stone were not directly visualized.

MRI's tissue contrast, lack of radiation, lack of known fetal bioeffects, and excellent accuracy makes it the study of choice in pregnant patients with abdominal pain.

Viswamitra, S, Hussaini, S, MRI is an Accurate First Line Imaging Modality for Evaluation of Pregnant Patients with Acute Abdomen.  Radiological Society of North America 2006 Scientific Assembly and Annual Meeting, November 26 - December 1, 2006 ,Chicago IL. http://archive.rsna.org/2006/4428588.html