[Postoperative Imaging Findings of Colorectal Surgery: A Pictorial Essay]

Abstract

Postoperative colorectal imaging studies play an important role in the detection of surgical complications and disease recurrence. In this pictorial essay, we briefly describe methods of surgery, imaging findings of their early and late complications, and postsurgical recurrence of cancer and inflammatory bowel disease.

Fig. 1. Anatomic schematic diagram of colon surgery.

A. Ileocecal resection. Terminal ileum, ileocolic valve and cecum are resected, and ileocolic vessels are also ligated. B. Right hemicolectomy. Right colon is resected, and ileocolic vessels, right colic vessels, and right branch of middle colic vessels are ligated. C. Extended right hemicolectomy. It includes ligation of the middle colic vessels at their base. D. Transverse colectomy. Transverse colon is resected, and middle colic vessels are ligated. E. Left hemicolectomy. Left colon is resected, and left branches of middle colic vessels, left colic vessels and first braches of sigmoid vessels are ligated. F. Extended left hemicolectomy. It includes ligation of the right branches of the middle colic vessels. G. Anterior resection (low ligation). Distal sigmoid colon and upper rectum are resected. Divisions of the inferior mesenteric artery is ligated, but left colic artery is preserved. H. Anterior resection (high ligation). It includes ligation of the inferior mesenteric artery at its origin. I. Subtotal colectomy. It involves resection of the entire colon excluding the sigmoid colon. Ileocolic vessels, right colic vessels, middle colic vessels, and left colic vessels are ligated. J. Total abdominal colectomy. Entire colon is resected and ileocolic vessels, right colic vessels, middle colic vessels, left colic vessels and sigmoidal vessels are ligated. K. Proctocolectomy. Entire colon, rectum and anus are resected. L. Hartmann’s operation. Distal or sigmoid colon is resected and diverting colostomy or ileostomy is made.

Fig. 2. Anatomic schematic diagram of rectal surgery.

A. Abdominoperineal resection. In this procedure, distal colon, rectum, anal canal and anus are removed, and permanent colostomy is created. B, C. Low anterior resection (B: low ligation, C: high ligation). Unlike abdominoperineal resection, anal canal and anus are preserved. Note the difference in the location of ligation of the inferior mesenteric artery between the two surgical methods.

Fig. 3. Subtype of abdominoperineal resection.

A, B. Unlike classical abdominoperineal resection (A), extralevator abdominoperineal resection (B) aims to achieve complete excision of the levator ani muscle surrounding the mesorectum adjacent to the cancer.

Fig. 4. Subtype of low anterior resection.

A, B. Low anterior resection (A) is performed for cancer located in upper-middle rectum. Generally, it is performed when the cancer is situated more than 5 cm away from the dentate line. In contrast, ultralow anterior resection (B) is performed for cancer located in the lower rectum, approximately 2 to 5 cm away from the dentate line.

Fig. 5. Anatomic schematic diagram of pelvic exenteration.

In this procedure, all the pelvic organs are removed. It can be performed when advanced rectal cancer invades adjacent structures such as the prostate, seminal vesicles, and bladder in males, or the uterus and posterior vaginal wall in females.

Fig. 6. Abdominal wound dehiscence.

On a contrast-enhanced postoperative CT scan performed 7 days after total colectomy for severe slow transit constipation, separation of the abdominal wall and a fluid collection is identified along the midline incision (arrows).

Fig. 7. Anastomotic leakage in a 68-year-old male who underwent a right hemicolectomy for cancer of the transverse colon.

A, B. On a contrast-enhanced axial CT scan performed 7 days after surgery, a fluid collection and air bubble are identified near the anastomosis site (arrows).

Fig. 8. Urologic injury in a 60-year-old male who underwent a right hemicolectomy for recurred liposarcoma of the right colon and double J stent insertion of the right urinary tract.

A. A preoperative contrast-enhanced coronal CT scan shows the proximity of the tumor and ureter (arrow). Double J stent insertion of the right urinary tract was planned due to the potential for ureteral injury during right hemicolectomy. Note the heterogeneously enhancing mass involving the right psoas muscle with infiltration of the terminal ileum, cecum, and right transverse abdominalis muscle. B, C. On a postoperative contrast-enhanced coronal and axial CT scan performed 20 days after surgery, there is right hydroureteronephrosis (arrow in B) and abrupt narrowing of the right ureter near the tumor excision site (arrow in C). Note a possible hematoma and fluid collection at the tumor excision site.

Fig. 9. Lymphocele in a 68-year-old male who underwent a robotic intersphincteric resection for rectal cancer.

On a contrast-enhanced axial CT scan performed 1 year after surgery, there is a cystic lesion at the right lateral pelvic side wall (arrow).

Fig. 10. Parastomal hernia in a 65-year-old male who underwent a Hartmann’s operation for a disrupted coloanal anastomosis with necrosis of his distal colon after LAR.

On a postoperative contrast-enhanced CT scan performed 19 months after the surgeries, there is protrusion of a loop of jejunum beyond the peritoneum at the previous ileostomy site of the Hartmann’s operation (arrow). It also presents an abscess in the right abdominal wall near the previous ileostomy site of the LAR (dotted arrow). LAR = low anterior resection

Fig. 11. Small bowel obstruction due to a parastomal adhesion after low anterior resection and ileostomy.

A postoperative CT scan performed 24 days after the LAR shows abrupt narrowing of the ileum near the ileostomy site, diffuse dilatation of the small bowel to more than 2.5 cm in diameter, and air-fluid levels. It also identifies a beak sign (dotted arrow) and adhesive band (arrow) near the transition zone.

Fig. 12. Sinus tract in a 56-year-old male who underwent low anterior resection for rectal cancer.

A, B. On water-soluble enema X-ray (A) and contrast-enhanced axial CT scans (B) performed 3 years after surgery, direct communication between the sinus cavity and rectal stump is identified. C. On a postoperative T2WI axial MR performed 3 years after surgery, an air-filled cavity (arrow) in the left lateral pelvic wall is identified. D. Contrast-enhanced T1 axial MR shows rim enhancement of the cavity (arrow).

Fig. 13. Anovaginal fistula in a 78-year-old female who underwent low anterior resection for rectal cancer.

A. On a water-soluble enema X-ray performed 2 weeks after surgery, a fistula (arrow) between the vagina and distal rectum is identified, note opacification of the cervix and uterus. B-D. On a contrast-enhanced axial CT and MR performed 2 weeks after surgery, a fistula (arrows) between the vagina and distal rectum is identified. Note the fluid collection of vagina and distal rectum.

Fig. 14. Anastomotic stricture in a 58-year-old female who underwent low anterior resection for rectal cancer. She complained of prolonged constipation and cramping lower abdominal pain after the surgery.

A, B. On postoperative axial CT scan performed 6 years after surgery, there is a focal narrowing of the colon at the anastomotic site (arrows) and distension of the proximal colon with diffuse fecal stasis. Mural wall thickening of the distended distal colon (dotted arrows), suggesting stercoral colitis, is also identified.

Fig. 15. Recurrence of Crohn’s disease in a 55-year-old female who underwent subtotal colectomy.

Contrast-enhanced axial CT scan performed 2 years after surgery shows a focal stricture (dotted arrow) with segmental asymmetric mural hyperenhancement (arrows) near the anastomosis site, suggestive of active Crohn’s disease with underlying fibrostenotic change.

Fig. 16. Local recurrence of rectal cancer in a 63-year-old male who underwent ultralow anterior resection for rectal cancer.

A, B. Postoperative contrast-enhanced axial CT scan performed 6 months after surgery shows a loculated fluid collection in the presacral space with surrounding soft tissue infiltration, suggestive of abscess formation. C, D. Postoperative contrast-enhanced axial CT scan performed 12 months after surgery shows interval development of an enhancing solid area in the loculated fluid collection and soft tissue nodules at the presacral space (arrows), suggestive of local recurrence of rectal cancer.

Fig. 17. Local recurrence of rectal cancer in a 74-year-old female who underwent low anterior resection.

A. T2-weighed axial MR performed 6 years after surgery shows an asymmetric circumferential soft tissue mass at the anastomosis site (arrow). The mass involved the right internal and external sphincters and puborectalis muscle. B. Diffusion-weighted image with b value 1000 showing diffusion restriction of the soft tissue mass at the anastomosis site (arrow).