To evaluate the clinical value of high-frame-rate contrast-enhanced ultrasound (H-CEUS) in grading and staging bladder cancer.

The H-CEUS features of 23 patients with bladder cancer treated at the First Medical Center, Chinese PLA General Hospital from January to March 2023 were retrospectively analyzed and compared with pathological examination results. According to pathological grades, the patients were divided into a low grade urothelium carcinoma (LGUC) group and a high grade urothelium carcinoma (HGUC) group. According to pathological stages, the patients were divided into a non-muscular invasive bladder cancer (NMIBC) group and a muscular invasive bladder cancer (MIBC) group. The t test was used to compare the difference in age and tumor diameter between patients with different grades and different stages. The Fisher exact test was used to analyze the differences in the number of vascular branches, vascular morphology, the source bladder wall layer from which microbubbles directly entering the lesion, and the integrity of the intrinsic muscle layer of the bladder wall at the base of the lesion observed by H-CEUS between patients with different grades and different stages.

The number of visible blood vessels within the lesion in the LGUC group (n=12) was mostly 1-2 (66.7%, 8/12), while it was ≥ 3 (54.5%, 6/11) in the HGUC group (n=11), with a statistically significant difference between the two groups (P=0.01). The percentage of patients with an intact mucosal layer was 83.3% (10/12) in the LGUC group, while it was 27.3% (3/11) in the HGUC group, with a statistically significant difference between the two groups (P=0.012). There was no significant difference between the LGUC group and HGUC group in patient’s age, lesion size, vascular morphology, and the source bladder wall layer from which microbubbles directly entering the lesion (P>0.05). The number of vessels in the NMIBC group (n=16) was 1-2 (68.7%, 11/16), while it was ≥ 3 (57.1%, 4/7) in the MIBC group (n=7), with a statistically significant difference between the two groups (P=0.003). Compared to MIBC, NMIBC had more microbubbles that entered into the lesion directly from the mucosal layer (75.0% vs 14.3%, P=0.019). Compared to NMIBC, MIBC mostly had an incomplete intrinsic muscle layer (100% vs 18.7%, P<0.001). There was no statistically significant difference between the NMIBC group and MIBC group in terms of lesion diameter, basal width, and vascular morphology.

H-CEUS greatly improves the contrast frame frequency, presents the perfusion details of the tumor to a large extent, and brings new diagnostic value to the staging and grading of bladder cancer.