Crucial computed tomography and magnetic resonance imaging findings of fallopian tubal tuberculosis for diagnosis: a retrospective study of 26 cases

Background: Fallopian tubal tuberculosis (FTTB), which typically presents with non-specific clinical symptoms and mimics ovarian malignancies clinically and radiologically, often affects young reproductive females and can lead to infertility if not promptly managed. Early diagnosis by imaging modalities is crucial for initiating timely anti-tuberculosis (anti-TB) treatment. Currently, comprehensive radiological descriptions of this relatively rare disease are limited. We aimed to comprehensively investigate the computed tomography (CT) and magnetic resonance imaging (MRI) characteristics of FTTB in patients from the Kashi area, which has the highest incidence of TB in China, to extend radiologists' understanding of this disease.

Methods: We conducted a retrospective cross-sectional study of 26 patients diagnosed with FTTB at the First People's Hospital of Kashi Area. All the patients underwent abdominal and pelvic contrast-enhanced CT examinations and/or pelvic contrast-enhanced MRI from January 2017 to June 2022. The imaging findings were evaluated in consensus by two experienced radiologists specialized in abdominal and pelvic imaging. The evaluated sites included the fallopian tubes, ovaries, peritoneum, mesentery, retroperitoneal nodes, and parailiac nodes. The patient characteristics are reported using descriptive statistics. The patient imaging results are presented as percentages. The normally distributed continuous variables are reported as the mean ± standard deviation (SD), and otherwise as the median with the interquartile range (IQR).

Results: The median age of the patients was 27 years (IQR: 25-34 years). Bilateral involvement of the fallopian tubes was observed in all patients. The tubal wall appeared coarse with tiny intraductal nodules in 96% (25 of 26) of the patients. The mean CT value of the tubal contents was 34 Hounsfield units (HUs; SD: 3.3 HUs). Ascites was present in 92% (24 of 26) of the patients, with 20 patients showing encapsulated effusion. Among these patients, 20 exhibited the highest CT values of ascites (>20 HUs). Linear enhancement of the parietal peritoneum was observed in 88% (23 of 26) of the patients, of whom 22 had peritoneal nodules measuring a median diameter of 0.4 cm (IQR: 0.3-0.6 cm). Eight patients had retroperitoneal and parailiac nodal enlargement, of whom two showed nodal necrosis, and none displayed nodal calcification.

Conclusions: FTTB is consistently accompanied by tuberculous peritonitis. FTTB typically presents with tubal dilation, and coarseness and nodules in the lumen, as well as intraductal caseous material and calcification. Tuberculous peritonitis exhibits high-density ascites, peritoneal adhesion, linear enhancement of the parietal peritoneum, and tiny peritoneal nodules. The co-occurrence of these features strongly suggests a diagnosis of FTTB.