# Evaluating Extended Field of View Imaging for Measuring Rectal Tumor Lowest Boundary to Anal Verge Distance via Transrectal Biplane Ultrasound

## TL;DR

This study shows that transrectal biplane ultrasound with extended field of view imaging is accurate and reliable for measuring rectal tumor distance to the anal verge.

## Contribution

The study demonstrates the accuracy and reproducibility of extended field of view transrectal biplane ultrasound for DTAV measurement in rectal cancer patients.

## Key findings

- Transrectal biplane ultrasound measurements showed excellent agreement with MRI and colonoscopy for DTAV.
- The ICC values for DTAV measurements between different ultrasound readings were 0.999, indicating high consistency.
- Radiologist reassessment of MRI data showed excellent consistency with original results (ICC = 0.985).

## Abstract

This study aimed to measure the precise distance from the lowest boundary of
a rectal tumor to the anal verge (DTAV) in patients with rectal cancer.

A retrospective analysis was performed on clinical data from 70 rectal cancer
patients. DTAV measurements were collected using transrectal biplane
ultrasound, MRI, and colonoscopy.

The difference in DTAV measurements between the mean DTAV value obtained by
ultrasound (US
mean
) and colonoscopy exhibited a difference of
0.22 cm. In contrast, the difference between US
mean
and MRI was
0.48 cm, while the difference between MRI and colonoscopy was −0.26 cm. The
ICC for DTAV measurements demonstrated excellent agreement, with values of
0.948 between US
mean
and MRI, 0.942 between US
mean
and
colonoscopy, and 0.943 between MRI and colonoscopy. The minimum DTAV value
obtained by ultrasound (US
min
) was 5.05 cm, the middle DTAV value
obtained by ultrasound (US
mid
) was 5.10 cm, and the maximum DTAV
value obtained by ultrasound (US
max
) was 5.30 cm. Notably, the
median values of the differences in DTAV measurements between
US
max
and US
min
, US
max
and
US
mid
, as well as US
mid
and US
min
, were
0.2 cm, 0.1 cm, and 0.1 cm, respectively. Furthermore, the consistency of
DTAV measurements between US
min
and US
mid
,
US
max
and US
mid
, as well as US
min
and
US
max
was excellent, with all ICC values reaching 0.999.
Additionally, the radiologistʼs reassessment of MRI DTAV data showed
excellent consistency with the original results, with an ICC value of 0.985.

Transrectal biplane ultrasound utilizing EFOV imaging technology exhibited
both accuracy and reproducibility for measuring DTAV. This approach provided
a highly efficient and practical clinical tool for DTAV measurement.