Time-intensity curve parameters in rectal cancer measured using endorectal ultrasonography with sterile coupling gels filling the rectum: correlations with tumor angiogenesis and clinicopathological features

Abstract

The primary aim of this study was to investigate the relationship between contrast-enhanced ultrasonography (CEUS) imaging parameters and clinicopathological features of rectal carcinoma and assess their potential as new radiological prognostic predictors. A total of 66 rectal carcinoma patients were analyzed with the time-intensity curve of CEUS. The parameter arrival time (AT), time to peak enhancement (TTP), wash-in time (WIT), enhanced intensity (EI), and ascending slope (AS) were measured. Microvessel density (MVD) was evaluated by immunohistochemical staining of surgical specimens. All findings were analysed prospectively and correlated with tumor staging, histological grading, and MVD. The mean values of AT, TTP, WIT, EI, and AS value of the rectal carcinoma were 10.84 ± 3.28 s, 20.61 ± 5.52 s, 9.78 ± 2.83 s, 28.68 ± 4.67 dB, and 3.20 ± 1.10, respectively. A positive linear correlation was found between the EI and MVD in rectal carcinoma (r = 0.295, P = 0.016), and there was a significant difference for EI among histological grading (r = -0.264, P = 0.007). EI decreased as T stage increased with a trend of association noted (P = 0.096). EI of contrast enhanced endorectal ultrasonography provides noninvasive biomarker of tumor angiogenesis in rectal cancer. CEUS data have the potential to predict patient prognosis.

Figure 1

Time-intensity curve (TIC) from region of interest (ROI) within the tumor and the ultrasound TIC parameters. Arrival time (AT), time to peak enhancement (TTP), wash-in time (WIT), enhanced intensity (EI), and ascending slope (AS).

Figure 2

Images of poorly differentiated rectal adenocarcinoma with T2 stage. (a) Endorectal ultrasonography showed that an irregular hypoechoic lesion invaded muscularis propria. (b) Time-intensity curve was obtained from ROI with EI = 36.83 dB, AT = 6.87 s, TTP = 14.57 s, WIT = 7.70 s, and AS = 4.78.  (c) Representative  photomicrographs of Immunohistochemical CD34 staining in the same tumor (200x magnification) showed microvasculature in brown and poorly differentiated rectal adenocarcinoma. The MVD value is 43.

Figure 3

Images of moderately differentiated rectal adenocarcinoma with T3 stage. (a) Endorectal ultrasonography showed an irregular hypoechoic lesion proceeded beyond the muscularis propria and serosa and perirectal fat. (b) Time-intensity curve was obtained from ROI with EI = 29.61 dB, AT = 5.83 s, TTP = 10.49 s, WIT = 4.66 s, and AS = 6.35. (c) Representative photomicrographs of Immunohistochemical CD34 staining in the same tumor (200x magnification) showed microvasculature in brown and moderately differentiated rectal adenocarcinoma. The MVD value is 24.

Figure 4

Images of well differentiated rectal adenocarcinoma with T1 stage. (a) Endorectal ultrasonography showed that an irregular hypoechoic lesion invaded both the mucosa and submucosa layer. (b) Time-intensity curve was obtained from ROI with EI = 25.21 dB, AT = 13.01 s, TTP = 25.12 s, WIT = 12.11 s, and AS = 2.08. (c) Representative photomicrographs of Immunohistochemical CD34 staining in the same tumor (200x magnification) showed microvasculature in brown and well differentiated rectal adenocarcinoma. The MVD value is 16.

Figure 5

Scatter plots show positive correlations between MVD and EI (r = 0.295, P = 0.016).

Figure 6

Scatter plots show negative correlations between histologic grade and EI (r = −0.264, P = 0.007).