TVUS is currently considered the single best diagnostic modality to assess for ectopic pregnancy [15]. In a retrospective study of 1,880 patients presenting to the emergency department with first trimester pain or vaginal bleeding, an overall accuracy of TVUS diagnosis was 78%, with a specificity above 90% but a low sensitivity of 35%. The sensitivity for ectopic and intrauterine pregnancy diagnosis is even lower in the absence of a yolk sac, 13% for ectopic pregnancy and 4% for intrauterine pregnancy. However, specificity is preserved in the absence of the yolk sac and remains above 90% [18]. A meta-analysis of 14 studies with 12,101 patients with ectopic pregnancy showed a positive likelihood ratio of 111 for the finding of adnexal mass without an intrauterine pregnancy on TVUS. This makes TVUS the single best diagnostic modality for evaluating patients with suspected ectopic pregnancy. A lack of adnexal abnormalities on TVUS decreases the likelihood of ectopic pregnancy with a negative likelihood ratio of 0.12 [15]. CT findings of tubo-ovarian abscess (TOA) include a thick-walled fluid density in adnexal location, septations within the mass, indistinct borders between the uterus and adjacent bowel loops, and gas bubbles within the mass. Other findings include thickening and anterior displacement of the round ligament, which suggest adnexal origin rather than gastrointestinal tract origin. Findings of a tubular cystic lesion with multiple satellite lesions were pathologically proven to be pyosalpinx in 10 of 14 cases [23]. The presence of a right ovarian vein entering a right pelvic abscess had a 100% specificity and 94% sensitivity to TOA and may help differentiate from peri-appendiceal abscess [24]. In the setting of endometriosis, CT evaluation may demonstrate secondary signs of architectural distortion, thickening of bowel serosa, or even bowel obstruction, although the imaging findings may not be specific to deep pelvic endometriosis.
Acute Pelvic Pain in the Reproductive Age Group. TVUS is currently considered the single best diagnostic modality to assess for ectopic pregnancy [15]. In a retrospective study of 1,880 patients presenting to the emergency department with first trimester pain or vaginal bleeding, an overall accuracy of TVUS diagnosis was 78%, with a specificity above 90% but a low sensitivity of 35%. The sensitivity for ectopic and intrauterine pregnancy diagnosis is even lower in the absence of a yolk sac, 13% for ectopic pregnancy and 4% for intrauterine pregnancy. However, specificity is preserved in the absence of the yolk sac and remains above 90% [18]. A meta-analysis of 14 studies with 12,101 patients with ectopic pregnancy showed a positive likelihood ratio of 111 for the finding of adnexal mass without an intrauterine pregnancy on TVUS. This makes TVUS the single best diagnostic modality for evaluating patients with suspected ectopic pregnancy. A lack of adnexal abnormalities on TVUS decreases the likelihood of ectopic pregnancy with a negative likelihood ratio of 0.12 [15]. CT findings of tubo-ovarian abscess (TOA) include a thick-walled fluid density in adnexal location, septations within the mass, indistinct borders between the uterus and adjacent bowel loops, and gas bubbles within the mass. Other findings include thickening and anterior displacement of the round ligament, which suggest adnexal origin rather than gastrointestinal tract origin. Findings of a tubular cystic lesion with multiple satellite lesions were pathologically proven to be pyosalpinx in 10 of 14 cases [23]. The presence of a right ovarian vein entering a right pelvic abscess had a 100% specificity and 94% sensitivity to TOA and may help differentiate from peri-appendiceal abscess [24]. In the setting of endometriosis, CT evaluation may demonstrate secondary signs of architectural distortion, thickening of bowel serosa, or even bowel obstruction, although the imaging findings may not be specific to deep pelvic endometriosis.