To provide a comprehensive review of anatomical landmarks of rectal and perirectal region.
To revise common and uncommon conditions in this complex anatomic region.
To highlight the imaging clues for their accurate diagnosis.
Rectum and perirectal space can be affected by a wide variety of tumours and tumour-like conditions,
which may present with similar symptoms to those of rectal adenocarcinoma,
such as hematochezia,
or change in bowel habits.
On the other hand,
tumours of the perirectal space are commonly congenital,
asymptomatic and they are malignant only in 20-35% of cases (1)
Anatomical characteristics of perirectal space are complex and magnetic resonance (MR) is the modality of choice for its assessment,
since it provides high soft tissue contrast...
Findings and procedure details
The rectum is approximately 15cm in length and layers can be well depicted by MR (Fig. 1):
Inner hyperintense layer,
mucosa and submucosa (differentiation may be difficult)
Intermediate hypointense layer,
Outer hyperintense layer,
perirectal fat tissue.
Mesorectum (Fig. 1) contains lymph nodes,
and several fibrous septa,
and is surrounded by the mesorectal fascia,
that represents the circumferential resection margin (CRM) when total mesorectal excision is used as the surgical approach.
The rectum is divided into thirds since outcomes and surgical management...
Anatomical characteristics of perirectal space are complex and magnetic resonance is the modality of choice for the evaluation of the entire bowel wall thickness and the perirectal tissues.
Radiologists should be able to recognize the key radiological features of conditions of the rectum and perirectal space,
so they can help the clinicians in their diagnosis and management.
José Miguel Escudero-Fernández
Department of abdominal imaging
Hospital Universitari Materno-Infantil Vall d’Hebron,
Institut català de la Salut.
Passeig de la Vall d’Hebron 119-129 08035 Barcelona Spain
Kalady MF et al.
Benign and malignant tumors of the rectum and perirectal region.
Abdom Imaging (2014) 39(4): 824-52
Koyama K et al.
Value of FDG-PET/CT Volumetry After Chemoradiotherapy in Rectal Cancer.
Dis Colon Rectum.
2018 Mar; 61(3): 320-327
Primary Anorectal Melanoma: MRI Findings and Clinicopathologic Correlations.
AJR 2018;211: W98-W108
Rosen A et al.
Imaging of acute anorectal conditions with CT and MRI.
Abdom Radiol (2017) 42:403–22....