Solving Pelvic Puzzles

The prompt diagnosis of acute non-traumatic pelvic pathology is one of the most clinically challenging aspects of emergency radiology. Presentations range from benign self-limited conditions to life-threatening emergencies requiring urgent surgical intervention. The review article by Sharma et al, ¹ provides a comprehensive review of current imaging approaches to non-traumatic female pelvic emergencies, supplemented with review of relevant anatomy and an algorithmic approach for patient imaging pathways. Their work addresses an important clinical problem: the diagnostic accuracy in evaluating acute pelvic pain remains variable across institutions and practitioners, creating potential for both missed diagnoses as well as unnecessary interventions.

Acute pelvic pain is a common reason for emergency department visits among women of reproductive age, yet diagnostic accuracy remains variable across institutions. The spectrum of potential diagnoses is broad and includes ovarian torsion, ruptured or hemorrhagic ovarian cysts, ectopic pregnancy, pelvic inflammatory disease, and tubal-ovarian abscess, in addition to numerous non-gynecologic entities such as appendicitis and diverticulitis. Each condition carries distinct prognostic implications and treatment urgency; however, imaging manifestations frequently overlap. For instance, hemoperitoneum can result from rupture of a hemorrhagic cyst, infarction from ovarian torsion, or ruptured ectopic pregnancy. These have vastly different management implications despite superficially similar sonographic findings. This diagnostic overlap, coupled with the time-sensitive nature of many acute pelvic emergencies, underscores the critical importance of imaging that integrates the clinical context. The review addresses this challenge by providing a framework for multimodality imaging evaluation that acknowledges both the strengths of individual imaging modalities and the clinical setting in which they are optimally employed.

Transvaginal and transabdominal ultrasound (US) is the first-line imaging modality for acute pelvic presentations, providing dynamic images, absence of ionizing radiation, and superior soft-tissue spatial and contrast resolution of adnexal structures compared to computed tomography (CT). A systematic approach to US evaluation, including thorough assessment of both adnexal regions, careful characterization of free fluid, and documentation of Doppler flow patterns, provides diagnostic information sufficient for diagnosis of most acute pelvic presentations.

US may prove inconclusive in some cases, in which case CT and magnetic resonance imaging (MRI) serve critical complementary roles. CT excels when diagnostic uncertainty extends beyond gynecologic pathology to encompass non-gynecologic emergencies such as appendicitis, diverticulitis, or ureterolithiasis. For patients with body habitus or acoustic windows precluding adequate US evaluation, CT provides valuable diagnostic information with radiation exposure acceptable given the clinical utility. MRI occupies a distinct niche, being particularly valuable in pregnant patients when radiation avoidance is desirable but US windows are suboptimal. MRI also serves as a valuable problem-solving tool for evaluation of complex pelvic lesions, offering superior tissue characterization that enables differentiation of overlapping features. Appropriate selection among these modalities requires understanding of their relative strengths and recognition that different clinical scenarios demand different imaging approaches. The ACR appropriateness criteria provides a structured framework for such decision-making. ²

In practical terms, however, the best imaging is often the modality that is immediately available when clinical evaluation is needed. In many centers, access to US may be more limited than CT in certain settings, such as after-hours coverage or facilities with limited sonographer staffing. For after-hours US coverage, institution-specific protocols often exist for on-call sonographer or radiologist-performed US, with variable availability depending on departmental structure and resource allocation. Institutions seeking to optimize emergency pelvic imaging should assess their specific operational constraints and establish departmental protocols that enable adherence to evidence-based imaging principles while acknowledging practical limitations of after-hours staffing and equipment availability.

Sharma et al, emphasize that thorough clinical history and physical examination are critical in narrowing the differential diagnosis and guiding appropriate investigations. This principle is of particular importance in pelvic imaging, where US exams are necessarily targeted and where high pre-test probability can guide special sonographic maneuvers to improve diagnostic accuracy. The authors provide the pertinent example of endometriosis, which has a classic presentation of acute-on-chronic cyclical pain. Real-time maneuvers such as the “uterine sliding sign,” where loss of normal sliding between the uterus and adjacent peritoneum suggests adhesions, can substantially improve diagnostic confidence. ³ Similarly, thorough review of patient history and laboratory markers can guide radiologists to assess for ancillary findings beyond the primary pathology. The authors use tubal-ovarian abscesses as an example, noting that in patients with suspected ruptured TOA, sequelae such as perihepatitis (Fitz-Hugh-Curtis syndrome) or ovarian vein thrombophlebitis can be assessed on US or CT, with identification allowing appropriate treatment and recognition of systemic complications.^4,5

Confident identification of “can’t miss” pathologies requires knowledge of non-classic presentations of common emergencies. The review provides a comprehensive overview of imaging signs associated with acute pelvic pathology, allowing for recognition of multiple findings rather than relying on any single diagnostic feature. Ovarian torsion illustrates this principle well. While torsion is commonly associated with absent color and spectral Doppler flow, published literature demonstrates that absent Doppler flow alone has limited sensitivity for this diagnosis. A meta-analysis by Garde et al found that absent Doppler flow has a pooled sensitivity of only 53% (95% CI: 34%-72%), meaning that normal or preserved Doppler flow does not exclude torsion. ⁶ A combination of multiple imaging signs including ovarian edema, twisting of the ovarian pedicle (“whirlpool sign”), and absent ovarian Doppler flow, when considered together, has been found to improve diagnostic performance substantially. This should influence how radiologists approach image interpretation and communicate findings to clinicians.

Sharma et al, provide a comprehensive review of imaging non-traumatic emergencies in the female pelvis, synthesizing current evidence regarding multimodality imaging approaches, clinical-radiologic integration, and diagnostic reasoning. The work underscores several fundamental principles in emergency radiology: the importance of systematic diagnostic approach, the appropriate selection of imaging modalities, and the integration of imaging findings with clinical context. For radiologists seeking to enhance their diagnostic accuracy and clinical relevance in the evaluation of acute pelvic pathology, this review provides valuable evidence-based guidance.

In conclusion, the article by Sharma et al, is a valuable contribution to the literature that provides a comprehensive review of a clinically important and frequently encountered presentation in emergency imaging.