Narrowband imaging useful in detecting additional areas of endometriosis

Narrowband imaging (NBI) at laparoscopy was able to detect additional areas of endometriosis not identified by standard white light, according to results of a study in The Journal of Minimally Invasive Gynecology.

The prospective study, which was conducted at Mercy Hospital for Women in Melbourne, Australia, found that of the 53 women eligible for analysis after undergoing laparoscopy for investigation of pelvic pain, several had an additional area of suspicion identified with NBI.

“The use of NBI at the time of laparoscopy has been proposed as a simple method for enhancing the visual markers for the detection and subsequent treatment of peritoneal endometriosis,” the authors wrote.

The average age of the cohort analyzed was 30 years, with an average body mass index of 25.4. In addition, 45% of patients were on some form of hormonal treatment at time of surgery. But no patient was on a gonadotropin-releasing hormone (GnRH) agonist.

Of the 36% of patients who previously had a laparoscopy, 50% were diagnosed with endometriosis.

As for patient symptoms, 77% of the women complained of cyclical pain, 53% of non-cyclical pain and 36% of dyspareunia, whereas 36% of patients noted abnormal uterine bleeding and 25% had associated bowel or urinary symptoms.

White light laparoscopy identified lesions suspicious for endometriosis in 32 of the 53 women, of whom 75% were positive for endometriosis.

A total of 89 white light-guided biopsies were conducted, of which 70% tested positive for endometriosis.

Moreover, 21% of the entire cohort had a single additional area of suspicion identified with NBI, of which 55% were positive for endometriosis.

Overall, 21 patients had a negative laparoscopy with white light, of which three had a single suspicious lesion detected by NBI. All three lesions tested negative for endometriosis, providing an additional positive predictive value (PPV) of 0% for NBI after a white light survey.

Of the 32 patients who had suspicious lesions detected by white light, 22% had a single additional area of suspicion identified with NBI. Six of these seven suspicious lesions detected by NBI tested positive for endometriosis on histopathology, translating to an additional PPV of 86%, if endometriosis is suspected on the white light survey. 

For the eight patients with white light biopsies that tested negative for endometriosis, histopathology reported three specimens as being connective tissue, two as fribroadipose tissue and one each as an epithelial cyst, normal peritoneum and fibromuscular tissue with calcification.

Only two of these eight patients had previous surgery to investigate endometriosis.

Of the five patients with NBI biopsies that tested negative for endometriosis, histopathology showed two as fibroadipose tissue and one each as fibrous peritoneal tissue, fibromuscular tissue with an old hemorrhage and mesothelial-lined fibrovascular tissue.

Two of the five patients had previous surgery for investigation of endometriosis.

The study’s endosurgery unit’s experience with NBI “has been beneficial, though it has not shown the same magnitude of benefit as other published studies,” the authors wrote.

On the other hand, they pointed to the advantages of NBI over other modalities for increasing detection of endometriosis at laparoscopy, including autofluorescence imaging (AFI), 5-aminolevulinic acid-induced fluorescence (5-ALA) and near-infrared imaging with indocyanine green (NIR-ICG).

With NBI, no patient medication is needed, thus avoiding potential side effects and cost of medication. NBI can also be employed via 5-mm ports and straight-stick laparoscopy, without having to contend with robotic technology or larger ports and incisions.

The authors note that surgeons or trainees who are less experienced in detecting endometriosis may find that NBI has benefit after negative white light survey. And it may have greater use in cases where endometriosis has already been identified with white light.