Transrectal ultrasonography: interpretation of normal intestinal wall structure for the preoperative staging of rectal cancer

The Gastrointestinal Wall Layers

Recent developments in the understanding of the sonographic appearance of the bowel wall, made possible by improvements in ultrasound technology, have given sonography a unique role to play in the evaluation of gastrointestinal lesions. Changes in wall thickness, alterations of normal structures, and complete obliteration of the entire wall structure can be observed. This report reviews the sonographic appearance of the histologic wall structures and shows cases that illustrate how the knowledge of those structures can help the sonographer to evaluate gastrointestinal lesions.

Evaluation of submucosal upper gastrointestinal tract lesions by endoscopic ultrasound

The proper diagnosis of submucosal upper gastrointestinal tract mass lesions by endoscopy or barium study is difficult. Differentiation between submucosal tumors, vascular structures, and extrinsic organs is often impossible. We performed endoscopic ultrasound examination of 91 patients with upper gastrointestinal submucosal mass lesions. Endoscopic ultrasound was accurate in determining the site of origin in 48 of 50 cases where pathology or angiography comparison was available. Leiomyoma, lipoma, varices, and carcinoma had characteristic ultrasonographic findings. Endoscopic ultrasound is a useful procedure in the evaluation of upper gastrointestinal submucosal mass lesions.

Transrectal and transvaginal ultrasonography in the preoperative staging of rectal carcinoma

To evaluate the diagnostic ability of transrectal and transvaginal ultrasonography (TRUS and TVUS), 132 patients with rectal carcinoma were examined. Analysis of the data obtained has shown that the high quality of endosonographic imaging allows the performance of detailed staging of rectal carcinoma. In the great majority of patients (91%) the staging was carried out correctly. Neoplastic invasion was overstaged in only five cases and understaged in another five cases. Altered pararectal lymph nodes could be visualized by endosonographic examination in 54.5% of patients.

Intrarectal and intra-anal ultrasonography in the evaluation of colorectal pathology

Recent advances in ultrasonography have improved significantly the accuracy and applicability of this technology to the management of anorectal pathology. Intrarectal ultrasonography has demonstrated a high degree of accuracy in the assessment of extent of local invasion of rectal carcinomas as well as the degree of regional lymph adenopathy. It also is capable of playing a significant role in the management of anorectal suppurative disorders by allowing identification of deep-seeded abscesses. This technology will play an expanding role in the management of anorectal disorders and should be in the armamentarium of the surgeon managing these problems.

Transrectal ultrasound study of the pathogenesis of solitary rectal ulcer syndrome

Transrectal ultrasonography is of clinical value in anorectal carcinoma and in inflammatory diseases of the anorectum. In this study a rigid linear endorectal probe was used to examine 15 patients with endoscopically and biopsy proved diagnosis of solitary rectal ulcer syndrome. In 13 of the 15 patients the rectal wall was thicker (mean (SEM) 5.7 (0.4) mm; normal values: 2.8 (0.1) mm) near the rectal ulcer. In all these cases the muscularis propria layer exceeded the maximum normal diameter of 2 mm. In nine of the 15 patients the normal rectal wall echo-structure, with five distinct layers, was disturbed and there was fading of the borders between the mucosa and the muscularis propria. Poor relaxation of the puborectalis muscle during straining was seen on ultrasound in 11 patients, as was intussusception of the rectal wall. The obvious enlargement of the muscularis propria points to a chronic mechanical load on the rectal wall. The ulcerative lesions are formed in this area of overloaded rectal wall. The direct visualisation of the puborectalis muscle during dynamic transrectal ultrasonography indicates that the fact that it does not relax is an important element in the pathogenesis of solitary rectal ulcer syndrome.

New diagnostic imaging in rectal cancer: endosonography and immunoscintigraphy

Endosonography of the rectum, combining the advantages of both endoscopy and sonography, provides information not at present available from other imaging modalities. It is remarkably accurate in the pre-operative assessment of tumor penetration. In the evaluation of lymph nodes, the specificity and sensitivity is 83% and 72%, respectively. For the detection of local recurrence in asymptomatic patients promising results can be obtained. In contrast, the potential benefits of immunoscintigraphy in patients with rectal cancer have yet to be determined but preliminary results indicate that immunoscintigraphy in combination with endosonography may assist the surgeon in confirming or excluding the suspicion of recurrence.

Value of transrectal ultrasonography in Crohn's disease

Anorectal lesions are common and can develop silently in patients with Crohn's disease. Transrectal ultrasound examinations were performed to study 40 healthy individuals and 40 patients with Crohn's disease. A rigid linear endorectal probe was used to examine the rectal wall, the perirectal tissues, and the anal sphincter. In healthy individuals, the rectal wall showed five layers with a total diameter of maximum 4 mm. The anal sphincter was clearly visualized as an echo-poor and sharply delineated structure. No pathological lesions were detected perirectally. In Crohn's disease, an enlargement of the rectal wall was seen in 16 patients and heterogeneity of the anal sphincter in 19 patients. This technique detected lesions missed with the routine proctological examinations: four pararectal abscesses, two pararectal fistulas, two para-anal abscesses, and one para-anal fistula. In all examined subjects, the anal sphincter increased in breadth during squeezing and in length during straining. It is concluded that transrectal ultrasonography sharply delineates the rectal wall and the anal sphincter at rest and under dynamic conditions and detects unknown abscesses and fistulas in the pararectal and para-anal tissues in patients with Crohn's disease.

The role of transvaginal sonography as compared with endorectal sonography in the evaluation of rectal cancer: preliminary study

We carried out a preliminary study on the efficacy of endovaginal sonography (EVS) in the evaluation of rectal cancer. The study included 12 women with endoscopically documented rectal cancer, 10 of which were treated surgically. We found that EVS evidenced metastasized lymph nodes (7/9) and infiltration of the rectovaginal space more clearly; moreover, this technique can also be performed in cases of stenosing cancer. Endorectal sonography (ERS) evidenced infiltration of the rectal wall but was less accurate both in detecting metastasized lymph nodes (6/9) and for exploration of the rectovaginal space. We concluded that the two methods complement one another and improve ultrasonographic staging of rectal cancer.

Preoperative staging of gastrointestinal tumors by endosonography

Intracavitary application of ultrasound was first performed for diagnostic purposes in 1967; since that time, it has been more and more widely used. As far as the gastrointestinal tract is concerned, endoscopically controlled ultrasonic probes provide visualization of the various layers of the intestinal wall. It is therefore possible to describe lesions of the esophagus, stomach, and the rectum with regard to their nature and depth of infiltration. Furthermore, periesophageal and perigastric organs can be visualized. It has become evident that endosonography is particularly important for pretherapeutic staging of tumors of the esophagus, stomach, and rectum. Here prospective comparative studies confirm the superiority of this new diagnostic procedure when compared to the methods available to date.

Endoscopic ultrasonography in the evaluation of colon and rectal disease

Endosonography of the colon has until recently been limited to examination of the rectum. Rigid and flexible instruments are currently available which allow for detailed images of the rectal wall. Comparative studies suggest that endosonography may be more accurate than computed tomography in the preoperative staging of rectal carcinoma. Recently, an ultrasound colonoscope has been developed which allows for visual examination, biopsy, and endosonography throughout the colon. Experience with this technique is limited and its role in the evaluation of colonic disease has not yet been determined. Further comparative trials are needed to more fully define the role of endosonography in the diagnosis of colorectal disease.

Indications of endoscopic ultrasonography of the digestive tract

Endoscopic ultrasonography of the digestive tract provides for a precise ultrasonic study of the accessible gastrointestinal walls (esophagus, stomach, duodenum, rectum) and through the walls, of the adjacent organs (lymph node clusters, posterior mediastinum, pancreas, extrahepatic biliary ducts and perirectal environment). This method is more efficient than computerized tomography to evaluate the local and regional extension of esophageal, gastric and rectal carcinomas, producing little or no stenosis. It is the examination of choice to detect a perianastomotic recurrence of these cancers in the aetiological diagnosis of obstacles in the biliary tract and in the diagnosis and the pretherapeutic assessment of pancreatic cancers.

Histologic correlates of gastrointestinal ultrasound images

Endoscopic ultrasound imaging has potential for improving the diagnosis of gastrointestinal disease. However, the anatomic correlates of gastrointestinal ultrasound images have not been precisely defined. We have compared ultrasound images with the corresponding histologic sections of 81 specimens of resected and postmortem, normal and diseased gastrointestinal tissue. The five layers seen on ultrasound images of the normal gastrointestinal tract correspond to (1) superficial mucosa, (2) deep mucosa, (3) submucosa plus the acoustical interface between the submucosa and muscularis propria, (4) muscularis propria minus the acoustical interface between the submucosa and muscularis propria, and (5) serosa and subserosal fat. This interpretation takes into consideration the echoes produced by the tissue layers and the echoes produced by the interfaces between layers. Abnormal findings on ultrasound images of neoplastic and inflammatory diseases correspond to histologic tissue structure. When properly interpreted, ultrasound images of the gastrointestinal wall can provide potentially useful diagnostic information.

Lower gastrointestinal endoultrasound

Following a brief history of transrectal ultrasonography, the author explains the fundamentals that led to his research on rectal echographic layers and then describes his theory as applied to the anatomical interpretation of these layers. Personal cases of preoperative staging with transrectal echography provide a basis for the critical evaluation of this method and its proposed role in clinical application.

Endosonographic staging of rectal carcinoma

Transrectal ultrasonography (US) scanning facilitates the ultrastructural differentiation of the various histologic layers of the rectal wall. In particular, the muscularis propria is represented by the 4th sonographic layer. Rectal carcinoma appears on US as a low echogenic area that suddenly interrupts the regular sequence of parietal layers. Sixty-five patients suffering with carcinoma of the lower two-thirds of the rectum underwent preoperative linear endosonography for staging. The reliability of such a method in assessing the extrarectal spread was evaluated in our study, at the end of which 55 sonographic/histologic correlations were obtained. Four false-negative and 1 false-positive determinations of the presence or absence of extrarectal spread proved that sonography has a sensitivity and specificity of 91%, with a positive predictive value of 97% and a negative predictive value of 71%. Lower results are obtained in lymph node staging: enlarged lymph nodes are seen in only 11/22 C1/C2 patients (11 false negatives) while we were aware of 3 false positives.