Diffusion-weighted imaging in ectopic pregnancy: ring of restriction sign

Area of Science:

• Radiology
• Medical Imaging
• Obstetrics and Gynecology

Background:

• Ectopic pregnancy (EP) is a life-threatening condition requiring accurate and timely diagnosis.
• Traditional diagnostic methods may have limitations in certain clinical scenarios.

Purpose of the Study:

• To illustrate the diffusion-weighted imaging (DWI) characteristics of ectopic pregnancy (EP).
• To introduce and define the "ring of restriction" sign in the context of EP.
• To discuss potential etiologies for this imaging finding.

Main Methods:

• Retrospective evaluation of patients diagnosed with EP between January 2014 and January 2017.
• Inclusion of patients who underwent Magnetic Resonance Imaging (MRI) on a 3T scanner.
• Detailed recording of MRI and DWI findings.

Main Results:

• Eight patients (20%) with EP underwent MRI and DWI.
• EP locations included ovary, tuba, Cesarean section scar, and parauterine regions.
• DWI demonstrated a thick-walled, cyst-like gestational sac with diffusion restriction in the wall, termed the "ring of restriction" sign, in all cases.

Conclusions:

• DWI provides valuable cellular and molecular information that can aid in EP diagnosis.
• Recognition of the "ring of restriction" sign on DWI can prevent misinterpretation, particularly in clinically ambiguous cases.
• This DWI finding can facilitate EP diagnosis without the need for contrast agents.