Value of biplane transrectal ultrasonography plus micro-flow imaging in preoperative T staging and rectal cancer diagnosis in combination with CEA/CA199 and MRI

Abstract

Background: Rectal cancer is one of the most common malignant tumors and has a high incidence rate and fatality rate. Accurate preoperative T staging of rectal cancer is critical for the selection of appropriate rectal cancer treatment. Various pre-operative imaging methods are available, and the identification of the most accurate method for clinical use is essential for patient care. We investigated the value of biplane transrectal ultrasonography (TRUS) combined with MFI in preoperative staging of rectal cancer and explored the value of combining TRUS plus MFI with CEA/CA199 and MRI.

Methods: A total of 87 patients from Daping Hospital with rectal cancer who underwent TRUS examination plus MFI were included. Grades of MFI were determined by Alder classification. Among the total patients, 64 underwent MRI and serum CEA/CA199 tests additionally within one week of TRUS. Pathological results were used as the gold standard for cancer staging. Concordance rates between TRUS, MRI, and CEA/CA199 for tumors at different stages were compared.

Results: There were no significant differences between the Alder classification and pathological T staging. The concordance rate of TRUS and MFI for rectal cancer T staging was 72.4% (K = 0.615, p < 0.001). Serum CEA and CA199 levels were significantly different in tumors at different stages and increased progressively by pathological stage (p < 0.001); the accuracy rate was 71.88% (K = 0.599, p < 0.001), while that of MRI was 51.56% (K = 0.303, p < 0.001), indicating that TRUS had higher consistency in the preoperative T staging of rectal cancer. The combination of TRUS, MRI, and CEA/CA199 yielded an accuracy rate of 90.6%, which was higher than that of any method alone.

Conclusions: Preoperative T staging of rectal cancer from biplane TRUS plus MFI was highly consistent with postoperative pathological T staging. TRUS combined with MRI and serum CEA/CA199 had a greater value in the diagnosis of rectal cancer and a higher diagnostic rate than any examination alone.

Keywords: Biplane TRUS; CA199; CEA; Combined; MFI; MRI; Rectal Cancer; Tumor staging.

Fig. 1

Exclusion process

Fig. 2

Images of a 47-year-old man with a T1 stage rectal tumor. (A) Two-dimensional endorectal biplane ultrasound of the line array revealed a hypoechoic mass on the rectal wall that was confined to the submucosa with a continuous hyper-echoic submucosa (arrow); the diagnosis was T1 rectal cancer. (B) An MFI mode image revealed that the microblood flow signals of the mass were abundant; there were more than four blood flow streams and spread to more than 50% of the maximum section of the tumor. (C) Magnetic resonance imaging revealing thickening of the wall of the lower rectum under peritoneal reflection (arrow); this was diagnosed as T1 rectal cancer. (D) The pathological diagnosis was moderately differentiated adenocarcinoma stage T1 as ulcerative type, and the cancerous tissue adjacent to the submucosa did not exceed the submucosa (arrow)

Fig. 3

Images of a 70-year-old man with a T2 stage rectal tumor. (A) Two-dimensional endorectal biplane ultrasound of the convex array revealed a hypoechoic mass on the rectal wall that penetrated the submucosa and was localized in the muscularis propria (arrows); the diagnosis was T2 rectal cancer. (B) An MFI mode image revealed that the microblood flow signals of the mass were abundant; there were more than four blood flow streams that spread to more than 50% of the maximum section of the tumor. (C) Magnetic resonance imaging revealed thickening of the wall of the lower rectum under peritoneal reflection (arrow); this was diagnosed as T2 rectal cancer. (D) The pathological diagnosis was moderately differentiated adenocarcinoma stage T2 as ulcerative type; the cancerous tissue (long arrow) had invaded the superficial muscularis propria (short arrow) and was confined to the muscularis propria (the entire view is filled with the muscularis propria)

Fig. 4

Images of a 68-year-old woman with a T3 stage rectal tumor. (A) Two-dimensional endorectal biplane ultrasound of the line array revealed a hypoechoic mass on the rectal wall that penetrated the submucosa and muscularis propria and infiltrated the perirectal tissue (arrow); the diagnosis was T3 rectal cancer. (B) An MFI mode image revealed that the microblood flow signals of the mass were abundant; there were more than four blood flow streams that had spread to more than 50% of the maximum section of the tumor. (C) Magnetic resonance imaging revealed tumor signals encroaching the muscle layers and reaching the perirectal fat (arrow). The diagnosis was T3 rectal cancer. (D) The pathologic diagnosis was moderately differentiated adenocarcinoma stage T3 as ulcerative type; the cancerous tissue (long black arrow) penetrated the muscularis propria (short black arrow) and invaded the subserosa (white arrow) and nerve

Fig. 5

Images of a 42-year-old man with a T4 stage rectal tumor. (A) Two-dimensional endorectal biplane ultrasound of the line array revealed a hypoechoic mass on the rectal wall that invaded the adjacent organs and nearby pelvic tissues (arrow). The diagnosis was T4 rectal cancer. (B) MFI mode image showing that the microblood flow signals of the mass are relatively abundant, with 3–4 short streams distributed below 50% of the maximum section of the tumor. (C) Magnetic resonance imaging revealed thickening of the wall of the lower rectum under peritoneal reflection (arrow); the diagnosis was T4 rectal cancer. (D) The pathologic diagnosis was moderately differentiated adenocarcinoma stage T4 as ulcerative type; the cancerous tissue invaded the adjacent organs and pelvic tissues (white long arrow, serosa; black long arrow, perirectal fat; black short arrow, nerve)

Fig. 6

Four MFI grades of RC.

Fig. 7

ROC curve of CEA and CA199. The AUC of CEA is 0.382; the AUC of CA199 is 0.507

Fig. 8

Accuracy of the four examination methods. n*, number of patients