Cross-sectional imaging of acute gynaecologic disorders: CT and MRI findings with differential diagnosis-part I: corpus luteum and haemorrhagic ovarian cysts, genital causes of haemoperitoneum and adnexal torsion

Abstract

Acute gynaecologic disorders are commonly encountered in daily clinical practice of emergency departments (ED) and predominantly occur in reproductive-age women. Since clinical presentation may be nonspecific and physical findings are often inconclusive, imaging is required for a timely and accurate diagnosis. Although ultrasound is the ideal non-invasive first-line technique, nowadays multidetector computed tomography (CT) is extensively used in the ED, particularly when a non-gynaecologic disorder is suspected and differential diagnosis from gastrointestinal and urologic diseases is needed. As a result, CT often provides the first diagnosis of female genital emergencies. If clinical conditions and scanner availability permit, magnetic resonance imaging (MRI) is superior to CT for further characterisation of gynaecologic abnormalities, due to the excellent soft-tissue contrast, intrinsic multiplanar capabilities and lack of ionising radiation.The purpose of this pictorial review is to provide radiologists with a thorough familiarity with gynaecologic emergencies by illustrating their cross-sectional imaging appearances. The present first section will review the CT and MRI findings of corpus luteum and haemorrhagic ovarian cysts, gynaecologic haemoperitoneum (from either ruptured corpus luteum or ectopic pregnancy) and adnexal torsion, with an emphasis on differential diagnosis. Additionally, comprehensive and time-efficient MRI acquisition protocols are provided.

Keywords: Computed tomography; Corpus luteum; Ectopic pregnancy; Gynaecologic emergencies; Magnetic resonance imaging.

Fig. 1

Typical appearance of an uncomplicated corpus luteum in the second half (luteal phase) of the menstrual cycle on axial (a) and coronal (b) CT images: the normal-sized right ovary (arrowhead) contains a 1.5-cm cystic structure demarcated by a crenulated, strongly enhancing peripheral rim (arrow)

Fig. 2

Usual MRI appearance of an uncomplicated corpus luteum in a 26-year-old woman. Oblique-coronal T2-weighted (a), oblique-coronal (b) and sagittal (c) gadolinium-enhanced fat-suppressed T1-weighted images show a small-sized, unilocular fluid-containing structure in the right ovary (arrowheads), with typical homogenous T1-hypointense signal and T2-hyperintense signal, thickened walls with a crenulated enhancing rim

Fig. 3

Uncomplicated, symptomatic follicular ovarian cyst causing left lower quadrant pain. Axial (a) and coronal (b) CT images show a 4 × 3 cm cystic mass (arrowheads) with homogeneous fluid attenuation, laterally displaced in the left hemipelvis. Identification of the ovarian vessels in the suspensory ligament (arrows) helps in confirming the adnexal origin of the cyst

Fig. 4

A surgically proven, progressively enlarging ovarian cyst. Initial unenhanced (a) and post-contrast (b) CT images depicted a 4 × 3 cm non-enhancing retrouterine cystic lesion (arrowheads) demarcated by a thin regular wall. Weeks later, MRI showed cyst enlargement with homogeneous T2-weighted fluid signal (c), without evidence of blood on precontrast fat-suppressed T1-weighted sequence (d), with unrestricted diffusion on apparent diffusion coefficient map (e) and thin uniform enhancing wall on post-gadolinium acquisition (f)

Fig. 5

MRI of a functional cyst causing pelvic pain in the periovulatory phase in a 37-year-old woman. Sagittal (a) and oblique-axial (b) T2-weighted images show a 4-cm well-marginated, unilocular cystic lesion with thin walls and homogeneous fluid-like signal intensity arising from the posterior edge of the left ovary (arrowheads), without haemorrhagic hyperintensity on sagittal precontrast fat-suppressed T1-weighted image (c)

Fig. 6

Two CT cases of haemorrhagic ovarian cysts. a, b The normal-sized left ovary (arrowheads) show mixed appearance with dependent high attenuation and fluid-fluid level (thin arrow in a) consistent with haemorrhagic corpus luteum. c, d Unenhanced (c) and post-contrast (d) images show a larger, bilocular adnexal lesion (arrowheads) with thin regular peripheral enhancement and dependent hyperattenuation (thin arrows). Note the ovarian vessels (arrow in d)

Fig. 7

Haemorrhagic corpus luteum and functional cyst in a 15-year-old woman with pelvic pain. Multiplanar T2-weighted (a–c) and precontrast fat-suppressed T1-weighted (d–f) images showed a right adnexal cyst (arrowheads) with internal fluid-fluid level and a bloody dependent component, T2-hypointense and T1-hyperintense. Contralaterally, a well-marginated unilocular cystic lesion of the left ovary (arrows) shows thin walls and homogeneous fluid-like signal intensity. Note the compressed ovarian parenchyma along the lateral edge of the cyst (thin arrow in b) and pelvic peritoneal effusion (asterisk)

Fig. 8

Flow-chart showing the MRI algorithm summarising the diagnostic steps for elucidating cystic ovarian masses

Fig. 9

Key CT differential diagnoses of haemorrhagic ovarian cysts. a, b Unenhanced (a) and postcontrast (b) CT images of bilateral endometriomas (arrowheads) occupying the rectouterine pouch in a ‘kissing ovaries’ configuration. Note the mildly inhomogeneous attenuation and septation (thin arrow in b). c, d Ovarian carcinoma in a premenopausal woman with predominantly cystic pattern, septations (thin arrow in d) and a solid, enhancing eccentric mural vegetation (asterisk in c). e, f Unenhanced (e) and post-contrast (f) images of a postoperative collection (complex serocele, arrowheads) involving the adnexal region, showing septations (thin arrows). Note the right ureteral stent and suture at the sigmoid colon after multiple surgeries for Crohn’s disease

Fig. 10

MRI of bilateral endometriomas in a 27-year-old woman with pelvic pain exacerbated in the last few days. Sagittal (a) and oblique-coronal (b) T2-weighted images show bilateral endometriomas with fluid-blood levels (arrowheads) and low signal intensity in the declivous portion of the cyst (‘shading sign’, arrows). On sagittal (c) and oblique-coronal (d) precontrast fat-suppressed T1-weighted images, the cysts demonstrate high signal intensity (arrowheads). Note the clot within right endometrioma with very high T1 signal intensity (thin arrows)

Fig. 11

MRI of bilateral endometriomas in a 31-year-old woman suffering from lumbar and pelvic pain. Oblique-axial (a) and oblique-coronal (b) T2-weighted images show bilateral endometriomas (arrowheads) with variable grade of low signal intensity until complete signal loss (‘shading sign’). On oblique-axial (c) and oblique-coronal (d) precontrast fat-suppressed T1-weighted images, the cysts display homogeneous high signal intensity (arrowheads)

Fig. 12

Haemoperitoneum shown at CT (a–c) as pelvic effusion (asterisk) with attenuation higher than that of water, caused by ruptured corpus luteum seen as a 3-cm right adnexal cystic lesion (arrowheads) with enhancing wall, surrounded by high-attenuation ‘sentinel clot’ (arrows)

Fig. 13

Two cases of haemoperitoneum from bleeding corpus luteum. a–c Unenhanced (a) and post-contrast (b, c) CT show hyperattenuating effusion (asterisk) in pelvis and paracolic gutters, mildly enlarged left ovary containing a characteristic corpus luteum (arrowheads) with focal discontinuity (thin arrow in b) of its strongly enhancing crenulated wall. d–f Unenhanced (d) and post-contrast (e, f) CT images show pelvic blood (asterisk) surrounding a 3-cm cystic lesion of the right ovary (arrowheads), from which contrast extravasated (arrows in e and f) indicating active bleeding

Fig. 14

Ruptured haemorrhagic corpus luteum with haemoperitoneum in an 18-year-old woman with pelvic pain for 24 h. Sagittal (a) and oblique-coronal (b) T2-weighted, sagittal (c) and oblique-coronal (d) precontrast fat-suppressed T1-weighted images show right-sided ovarian cyst (arrowheads) with internal fluid-fluid level and a dependent component with intermediate signal intensity on T1- and T2-weighted images (thin arrows), corresponding to recent haemorrhage (< 48 h). Note the haemorrhagic peritoneal effusion with intermediate signal intensity on both T1 and T2-weighted images adjacent to the posterior aspect of the cyst (arrows)

Fig. 15

Ruptured corpus luteum in a 20-year-old woman with pelvic pain and fever over the previous 2 days. Oblique-axial (a), sagittal (b) and oblique-coronal (c) T2-weighted and sagittal precontrast fat-suppressed T1-weighted (d) images show a haemorrhagic collection (arrowheads), T2-hypointense and T1-hyperintense, in the pouch of Douglas, contiguous to the left ovary (arrow in a). The latter represents the source of bleeding, although the corpus luteum is no longer recognizable

Fig. 16

Two surgically proven cases of haemoperitoneum from early extrauterine pregnancy. a–c Unenhanced (a) and postcontrast (b, c) CT images show diffuse hyperattenuating peritoneal effusion (asterisk), enlarged left ovary containing a focal contrast extravasation (arrows in b and c) indicating active bleeding. d–f Unenhanced (d) and postcontrast (e, f) CT images show haemoperitoneum (asterisk), bilateral cystic-like ovarian lesions (arrowheads) with active haemorrhage on the left side (arrows in e and f)

Fig. 17

MRI of a ruptured first-trimester ectopic pregnancy in a 44-year-old woman with acute abdominal pain and elevated β-hCG levels. Sagittal (a) and oblique-coronal (b) T2-weighted images show a tubular left adnexal mass (arrowheads) containing a gestational sac in the isthmus of the fallopian tube (arrows). On oblique-coronal fat-suppressed T1-weighted image (d), the distended fallopian tube displays a thick hyperintense wall (arrow) consistent with haematosalpinx. Additionally, sagittal T2-weighted image (c) demonstrates a predominantly low-signal haemorrhagic fluid collection (asterisk) in the pouch of Douglas. Note the empty endometrial cavity (thin arrow)

Fig. 18

Two surgically proven cases of adnexal torsion. a, b Axial (a) and coronal (b) CT images show enlarged left ovary (arrowheads) with thickened oedematous periphery (thin arrows), containing a mixed-attenuation roundish mass with fat-attenuation foci and a calcification, corresponding to a mature cystic teratoma. Note the ipsilateral attraction of uterus (+), minimal fluid in the peritoneal cul-de sac (asterisk in a). c–f Unenhanced (a) and post-contrast (d–f) CT images show large midline pelvic mass (arrowheads) consistent with malignant teratoma with poor, irregular enhancement that displaces the uterus and bladder. Note the peritoneal effusion (asterisk) and congested ovarian vessels on the right side

Fig. 19

Right adnexal torsion in a 24-year-old woman with acute abdominal pain and leukocytosis. Multiplanar T2-weighted (a–d), oblique-axial precontrast fat-suppressed T1-weighted (e) and oblique-axial gadolinium-enhanced fat-suppressed T1-weighted (f) images show an enlarged (10 cm diameter) right ovary (arrowheads) with afollicular T2-hyperintense central stroma (asterisk in b and c), peripheral follicles (‘pearl string sign’, thin arrows in b and d) and corpus luteum (arrow in a). The normal left ovary is also seen (black arrowhead in b). Note the engorged blood vessels along the posterior portion of the right adnexa (black arrows in a, c and f). The enlarged right ovary shows homogeneous intermediate T1-weighted signal intensity (asterisk in e), without hyperintense haemorrhagic changes, reflecting the early stage of torsion. The patient underwent laparoscopic detorsion with adnexal sparing

Fig. 20

Unilateral massive ovarian oedema in a 23-year-old woman with recurrent self-limiting episodes of acute pelvic pain in the last year. Oblique coronal T2-weighted image (a) shows enlargement (4 cm diameter) of the right ovary (arrowhead) characterised by oedematous hyperintense stroma; follicles (thin arrow) and corpus luteum (arrow) are displaced at the periphery of the cortex. Moderate peritoneal effusion (asterisk) coexists. Oblique coronal T2-weighted image (b) demonstrates the normal-appearing left ovary (black arrowhead)

Fig. 21

Pelvic congestion syndrome. Axial (a) and coronal (b) CT images showing asymmetric dilatation of the pelvic venous plexus (arrows) reaching 6 mm maximum calibre on the left side

Fig. 22

MRI of pelvic congestion syndrome in a 26-year-old woman with chronic pelvic pain and a recent severe exacerbation. Oblique-coronal T2-weighted image (a) shows ectatic vascular structures in the parametria, showing predominantly high signal intensity (arrowheads); in the left parametrium, some varices (arrow) display low signal intensity. Corresponding oblique-coronal gadolinium-enhanced fat-suppressed T1-weighted image (b) demonstrates vascular enhancement of the abovementioned structures (arrowheads), thus confirming pelvic varices

Fig. 23

Pelvic varices from nutcracker syndrome in a 24-year-old woman with severe pelvic pain. Axial gadolinium-enhanced fat-suppressed T1-weighted images (a, c) demonstrate compression of left renal vein (‘beak sign’, arrow) between the abdominal aorta and superior mesenteric artery (thin arrow) and enlarged left gonadal vein (arrowhead). Additional sagittal maximum-intensity projection (MIP) reconstruction (b) demonstrates the left renal vein (arrow) within a narrow angle between the abdominal aorta and the superior mesenteric artery (thin arrow), consistent with ‘nutcracker syndrome’. Axial angiographic MIP image (d) demonstrates dilated, engorged left parametrial and uterine veins (arrowhead). Note the dilatation of contralateral parametrial plexus (black arrowhead) due to the anastomosis via the arcuate uterine veins

Fig. 24

In the same patient as in Fig. 22, multiplanar T2-weighted images demonstrate severely congested pelvic veins (arrowheads in a), cystic components in both ovaries (arrows in b), and dilated arcuate veins in the subserosal portion of the myometrium (thin arrows in c)