ESR Essentials: Gynaecological causes of acute pelvic pain in women: a primer for emergent evaluation-practice recommendations by the European Society of Emergency Radiology

Abstract

Acute pelvic pain (APP) is a common presentation in women of all ages and has both gynaecological and non-gynaecological causes. In the emergency department, the suspected differential diagnosis dictates the chosen imaging modality. For premenopausal patients with APP, transabdominal ultrasound (TAUS) and transvaginal ultrasound (TVUS) are first-line investigations with high sensitivity and specificity for ectopic pregnancy, adnexal torsion, and ovarian cysts and their complications. US may also be valuable in pelvic inflammatory disease. When a non-gynaecological cause is suspected, contrast-enhanced CT (± transabdominal US) is indicated and has the advantage of 24/7 availability and lack of operator dependence. CT, however, may reveal an unexpected gynaecological cause of APP. When available, MRI is an excellent second test to improve diagnostic certainty in pregnant women when US is inconclusive-both for gynaecological and non-gynaecological conditions. MRI has a high diagnostic accuracy for pelvic inflammatory disease and tubo-ovarian abscesses. This article will enable readers to refresh their knowledge of common causes of APP and understand the histopathological processes involved in gynaecological causes of APP and how the imaging findings correlate. It will outline why different modalities are useful in different pathologies and help understand the limitations of each modality, including the requirement for operator expertise (US), relative lack of specificity/sensitivity (CT), and limited availability (MRI). This article excludes pregnancy-related causes of APP (apart from ectopic pregnancy) and also excludes non-gynaecological causes of APP. KEY POINTS: In female patients with acute pelvic pain, ultrasound is the best first modality in suspected gynaecological pathology. CT can be used when non-gynaecological causes of pain are suspected and when US is inconclusive. MRI has limited availability in an emergency setting and may be used in pelvic inflammatory disease and in pregnancy when US is inconclusive.

Keywords: Computed tomography; Gynaecological examination; Magnetic resonance imaging; Pelvic pain; Ultrasonography.

Fig. 1

Pelvic inflammatory disease (pyosalpinx) in two different patients presenting with acute pelvic pain and fever. a Transabdominal grey-scale US and (b) transvaginal Doppler image show thick-walled dilated tubular adnexal structures (arrows in a), distended with echogenic fluid-debris levels (dashed arrows) with surrounding vascularity with Doppler ultrasound. c Transabdominal grey-scale US image in a different patient, shows bilateral cystic structures (arrows) surrounding the uterus (U) containing hyperechoic material compatible with pyosalpinx. The ovaries show multiple follicles (arrowheads). d, e Coronal and axial post-contrast CT images, respectively, of the same patient, demonstrate both ovaries with multiple follicles (arrowheads) and bilateral thick-walled dilated tubular structures (arrows) representing the dilated fallopian tubes

Fig. 2

Surgically confirmed tubo-ovarian abscess in two different patients. a, b Middle-aged woman with lower abdominal pain, fever and vaginal discharge. a Transabdominal grey-scale ultrasound shows a large cystic complex mass representing a tubo-ovarian complex with echogenic content consistent with pus. b Microflow ultrasound imaging demonstrates peripheral vascularity in the walls of the cystic lesion without internal vascularity in keeping with the cystic nature of the mass. c–e Young woman with pelvic pain and raised inflammatory markers. Consecutive axial (a, b) and coronal (c) CECT images, venous phase, show bilateral pyosalpinx (dotted arrows) and a right ovarian abscess (asterisk). Note the fat stranding around the fallopian tubes (arrows) and the markedly thickened uterosacral ligaments (arrowheads)

Fig. 3

A–C Red degeneration on an intramural fibroid in a postmenopausal patient with acute pelvic pain and known fibroids. Sagittal T2, T1-FS pre and post-gadolinium MRI images, respectively, show intramural fibroids (arrows) with (A) central heterogeneous T2 signal, (B) hyperintense on T1 fat sat (haemorrhage) and (C) non-enhancement in the post-contrast images in keeping with infarction. D, E Myometrial abscess in a patient with pelvic pain and vaginal discharge. Axial and sagittal post-contrast CT images show pelvic fluid (asterisk), fat stranding and thickening and oedema of the uterosacral ligaments (arrows). A uterine intramural hypodense abscess (arrowheads) was noted communicating with the endometrial cavity which is distended with fluid

Fig. 4

Complicated ovarian cyst in a young woman in her late teens presenting with acute pelvic pain, nausea and vomiting. a, b Transabdominal grey-scale and Doppler US shows a complex cystic mass with hyperechoic content (arrow) without vascularisation in Doppler images. c–e Portal venous phase axial and coronal CT images demonstrate a large amount of hemoperitoneum (asterisk) in the abdomen and pelvis. The images through the pelvis show a right para-uterine cystic mass (black arrows) with multiple hyperdense foci within related to active bleeding. Large hemoperitoneum with sentinel clot in the pelvis. Findings suspicious for ruptured ovarian cyst with active bleeding. Surgery confirmed ruptured corpus luteal cyst. f, g Endometrioma in a young woman with acute left quadrant pain. Axial T1-FS WI (f) shows a large left ovarian cyst with high signal intensity and a fluid-fluid level (arrow). In the axial T2 WI (g), the adnexal lesion shows marked signal loss due to cycling bleeding (shadowing sign). Note the right ovarian follicular cyst (arrowhead)

Fig. 5

Ovarian hyperstimulation syndrome in two different patients. a–d Women in her 30’s undergoing in vitro fertilisation presented with abdominal distention, nausea and vomiting. TAUS (a, b) and TVUS (c, d) demonstrate ascites (arrow in a), enlarged ovaries (black arrows) with preserved central flow (b) and multiple follicles of varying sizes (b–d) consistent with OHSS. e, f Different patient in her early 30’s and 15 weeks pregnant presented with abdominal pain. Sagittal T2WI at the level of the right and left adnexal regions show markedly enlarged bilateral ovaries (arrows) containing multiple large, thin-walled cysts consisted with OHSS. P (placenta). MRI can provide better characterisation of the ovarian process in the differential diagnosis of ovarian tumours

Fig. 6

Right adnexal torsion in a woman in her 40’s with intense right pelvic pain and vomiting. CT was requested to exclude appendicitis. a–c Post-contrast coronal (a) and axial CT images (b, c) excluded appendicitis and showed an enlarged and hypodense right ovary (arrow) posteriorly displaced behind the uterus in the axial images, compared to the normal size and located left ovary (arrowhead) and twisted right fallopian tube (dotted arrows). d, e Subsequent transvaginal US performed preoperatively by the gynaecologist confirmed the CT findings with an enlarged and oedematous right ovary (arrow) measuring approximately 98 × 42 mm with distended peripheral follicles (curved arrows). f Intraoperative image confirmed right ovarian necrosis

Fig. 7

Ectopic pregnancies in three different patients. a–c Teenager with intense abdominal pain and persistent vaginal bleeding. Grey-scale US images show a large amount of partially echogenic abdominal fluid (asterisk) and a pelvic haematoma (star) surrounding the uterus (U). A round, thick-walled para-uterine cystic mass (arrow) with vascularised wall and a fetal pole was noted with Colour Doppler (d). No gestational sac was identified within the endometrial cavity. Laparoscopic surgery confirmed a ruptured ectopic tubal pregnancy with extensive hemoperitoneum. e–g Axial post-contrast CT images in a different patient with a ruptured tubal EP. Normal right adnexa is noted (black arrow), separate from a ring-enhancing right para-uterine cystic mass (dotted arrow) which increases the likelihood that the cystic mass represents an ectopic pregnancy. Active bleeding from the ruptured tubal pregnancy is visible during the arterial phase (arrowhead). h Woman in her 20’s presenting in the emergency department with acute pelvic pain and vaginal bleeding. Coronal T2 WI shows an eccentric gestational sac (arrow) with a fetal pole (arrowhead) located in the interstitial segment of the right Fallopian tube, next to the uterus (U). MRI is more helpful in evaluating ectopic interstitial pregnancy, which is a diagnostic challenge on ultrasound

Fig. 8

Flowchart of investigation of a female with acute pelvic pain. β HCG, beta humanchorionic gonadotropin; POS, positive; NEG, negative; US, ultrasound; CT, computed tomography; MRI, magnetic resonance imaging; PID, pelvic inflammatory disease. *Gynaecological causes, **Non-gynaecological causes, and ^{^}MRI: consider MRI in these clinical scenarios in pregnant or very young women