Features of time–intensity curve parameters of colorectal adenocarcinomas evaluated by double-contrast enhanced ultrasonography: Initial observation

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Abstract

Purpose

This study is to investigate the value of double contrast-enhanced ultrasonography (DCEU) in assessing microcirculation of colorectal adenocarcinomas and to describe the perfusion features of the tumours.

Material and methods

DCEUS was performed in 42 patients with adenocarcinoma. The time–intensity curve parameters (arrival time (AT), time-to-peak (TTP), peak intensity (PI) and area under the curve (AUC)) within the tumours were extracted. The parameters were compared among the tumours with different CEUS features and stages.

Results

The mean values of AT, TTP, PI and AUC of the colorectal adenocarcinomas were 13.68 ± 13.36 s, 32.61 ± 19.56 s, 19.82 ± 16.54 dB and 271.10 ± 159.19 dB s, respectively. In the adenocarcinomas with necrosis, the mean values of AUC was significantly lower than that of the adenocarcinomas without (231.10 ± 219.27 dB s, 278.10 ± 123.20 dB s, p = 0.004). In the adenocarcinomas with necrosis, the AUC and PI of the non-necrotic part were significantly higher than that of the necrotic part (p = 0.007, 0.0025, respectively). AUC increased progressively in the subgroups of T2, T3 and T4 and the difference of AUC between T2 and T4 subgroup was significant (p = 0.008).

Conclusions

Double contrast-enhanced ultrasonography is a valuable technique for quantifying tumour vascularity of colorectal adenocarcinomas. AUC was significantly different in the subgroups of different T stage. AUC and PI could reflect the different perfusion status of tumours with or without necrosis.

Introduction

Colorectal cancer is one of the leading causes of cancer death in both developed and developing nations. Worldwide, >900,000 new cases of colorectal cancer are diagnosed each year, and colorectal cancer accounts for nearly 500,000 cancer deaths annually [1]. Adenocarcinomas are the most common type of colorectal cancer and account for about 90–95% of all colorectal cancers. Compared with barium enema and colonoscopy, sonography is non-radiating, non-invasive and does not need anaesthesia. Sonography was previously considered inappropriate for evaluation of the gastrointestinal tract [2], [3]. This common view was based on the fact that bowel loops contain gas, which is considered to be the major impediment to the visualization of the gastrointestinal tract. And the use of luminal contrast agents in bowel can improve the results [4]. In recent years the use of second-generation contrast agents with low mechanical index (MI) real-time harmonic sonography has made microvascular imaging possible [5], [6], [7], which can display the simple backscattering sound wave of microbubbles with minimized bubble destruction and permit prolonged evaluation of the hemodynamic distribution of the contrast agent in real time. There is only very limited information and published literature regarding the contrast-enhanced ultrasound (CEUS) in intestinal diseases [8], [9], [10]. To the best of our knowledge, there were no reports focusing on the ultrasound perfusion features of the colorectal adenocarcinomas. The purpose of this study was to investigate the value of double contrast-enhanced ultrasonography (DCEUS) in assessing microcirculation of colorectal adenocarcinoma and to describe the perfusion features of the tumour. In DCEUS, SonoVue was used combined with a kind of intestinal luminal contrast agent.

Section snippets

Study group

From January 2010 to July 2010, 56 consecutive patients were enrolled for DCEUS. All patients were confirmed with discovered tumours by means of endoscopic biopsy. The exclusion criteria as follows: (1) undergone pre-operative treatments such as chemotherapy and radiotherapy; (2) incapable of cooperating with examination and tolerating the enema; (3) with contraindications to the contrast agent-SonoVue within the terms of the applicable country product license (i.e., pregnancy, childhood,

Statistical analyses

Statistical analyses were performed with statistical softwares (MedCalc Statistical Software, version 9.2 and SPSS, version 14.0). Data were expressed as means ± standard deviation (SD). In the Bland–Altman analysis, the mean difference, the SD, and 95% limits of agreement were established. Repeatability of perfusion study between the two sets of measurements of colorectal adenocarcinomas was assessed using Bland–Altman analysis and the intraclass correlation coefficient (ICC). The independent

Results

The conventional ultrasonography, hydrocolonal ultrasonography and the DCEUS were performed successfully in all patients. All patients tolerated the examinations well, and no complications occurred. Subdivided according to the morphology of the tumours, 17 cases were type I and 25 cases were type II in our study. Necrosis were found in 15 (15/42, 35.7%) adenocarcinomas in our series, measured 2.6–7.5 cm in the largest diameter (mean 3.5 ± 4.2 cm). All of them showed inhomogeneity in grey-scale and

Discussion

With an estimated 146,940 new colorectal cancer cases and 56,730 colorectal cancer deaths in the year 2004, colorectal cancer is the fourth most commonly diagnosed cancer in the United States and is associated with the second highest mortality after lung cancer [11]. Since the late 1980s, sonographic evaluations of the colon after an enema using water or other contrast agent, also known as hydrocolonic sonography or contrast enhanced intestinal ultrasonography, have been proposed as an

Conclusion

In conclusion, our initial experience suggests that DCEUS could be useful for assessing tumour vascularity of colorectal adenocarcinomas. AUC was significantly different in the subgroups of different T stage. AUC and PI could reflect the different perfusion status of the colorectal adenocarcinomas with or without necrosis. Further study is needed to investigate the relationship between the significant TIC parameters and tumour angiogenesis in the future. A better understanding of the colorectal

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