In a patient with cervical motion tenderness and suspected pelvic inflammatory disease (PID), what is the role of imaging?
PID is typically a clinical diagnosis, although imaging can assist in early diagnosis and in identifying potential complications. Transvaginal US is the initial imaging study of choice in most cases and can be helpful in establishing a diagnosis of PID. A thickened appearance of the tubal walls seen on US is the most useful diagnostic clue with high (>90%) specificity and with sensitivity ranging from 30% to 100%. Tubo-ovarian abscess (TOA) is identified on US as a nonspecific complex adnexal mass. CT also plays a role in visualizing pyosalpinx, TOA, and right upper quadrant peritonitis related to Fitz-Hugh-Curtis syndrome ( Figure 38-12 ). Although the overall sensitivity of CT signs for diagnosis of acute PID is limited, it can help confirm a suspected diagnosis of PID. The most specific CT imaging finding is thickening of the fallopian tubes. Subtle infiltration or haziness of the pelvic mesenteric fat is one of the earliest findings of PID that may be encountered on CT or MRI.