Anorectal imaging

Fig. 14.1. (A) Implantation of HT-29LP tumor cells into the posterior wall of the rectum. The anterior wall of the anorectal area is cut 7 mm in length between two hemostats to prevent colonic obstruction, resulting from tumor progression. Tumor cells are then injected submucosally using a 27 G needle. (B) At the end of the study period, the abdominal cavity is exposed through a midline incision and para-aortic lymph nodes (arrow), located around the abdominal aorta, are removed and imaged ex vivo.

Table6.1. Suggested guidelines (Nievelstein et al. 1998b) for MR protocol for neonates and infants with anorectal malformations (based on a 1-T or 1.5-T magnet using ahead coil for neonates and a phased arraybody coil for older children). Axial and coronal planes should be angled to be parallel and perpendicular to the pelvic floor. Imaging of the spinal cord and kidneys is only necessary if associated anomalies are suspected...

Nievelstein RA, van der Werff JF, Verbeek FJ et al (1998a) Normal and abnormal embryonic development of the anorectum in human embryos. Teratology 57 70-78 Nievelstein RAJ, Vos A, Valk J (1998b) MR imaging of anorectal malformations and associated anomalies. Eur Radiol 8 573-581... 

Sato Y, Pringle KC, Bergman RA et al (1988) Congenital anorectal anomalies MR imaging. Radiology 168 157-162... 

Fig.8.32a,b. False positive diagnosis internal haemorrhoids a axial image shows irregular, linear structures at the anorectal region (arrows) b corresponding endoluminal 3D image shows linear, smoothly delineated structmes at the anorectal junction, (arrows)... 

Fig. 8.38a,b. False positive diagnosis intermittently prolapsing rectal mucosa a axial image shows a smooth soft tissue filling defect at the anorectal region (arrow) b endoluminal 3D image shows an apparent low rectal mass (arrows). Conventional colonoscopy showed edematous mucosa due to rectal prolapse. Lesson Rectal mucosa can appear very prominent, particularly in case of mucosal prolapse, simulating low rectal masses... 

The entire spectrum of imaging investigations and functional studies is necessary to detect urogenital anomalies in anorectal malformations. 

Ralph DJ, Woodhouse CRJ, Ransley PG (1992) The management of the neuropathic bladder in adolescents with imperforate anus. J Urol 148 366-368 Rivosecchi M, Lucchetti MC, Zaccara A et al (1995) Spinal dysraphism detected by magnetic resonance imaging in patients with anorectal anomalies incidence and clinical significance. J Pediatr Surg 30 488-490 Stephens FD, Smith ED (1971) Ano-rectal malformations in children. Year Book, Chicago... 

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