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Rectal cancer staging with PET/MRI

Patient’s history

A 59 years old male patient presented with rectal bleeding and recently pathologically proven rectal adenocarcinoma. PET/MRI was performed for local rectal staging, nodal and metastatic workup.

Fig. 1

Local staging: [T]

  • Circumferential irregular mural thickening is seen implicating the mid and upper rectum where this mass lesion is measuring about 6.7 x 4.5 x3.5 cm. (Yellow arrows)
  • It is infiltrating the muscularis propria with multiple sizable extra mural extension into the surrounding meso-rectum, reaching a thickness of about 23mm. (White arrows)
  • Significant extra mural vascular invasion is seen.
  • There is infiltration of the peritoneal reflection noted at the pelvis. (red arrows)
  • The mass showed:
    • Significant restricted diffusion with mean ADC value of about 0.5×10-3 mm2 /sec.
    • Increased metabolic activity reaching 30 SUVmax.
    • Significant hyper-enhancement with pronounced increased K-trans value of 0.616, for the mass compared to 0.08, for the normal lower rectum.
Fig. 2

Nodal staging: [N]

  • Multiple enlarged hypermetabolic lymph nodes are noted at perirectal, presacral and right internal iliac regions. (Yellow arrows)
  • The perirectal lymph nodes are seen inseparable from the meso-rectal fascia on both sides. (positive circumferential resection margin) (White arrows).
Fig. 2

Distant Metastasis: [M]

  • The liver shows multiple hypermetabolic and diffusion restricted bilobar focal lesions. (yellow arrows)

Overall staging:

  • T4a, N2, M1.



This Case was kindly provided by:

Yasser Abd El-Azim Abbas, M.D., Ph.D.
Misr Radiology Center
Department of Radiology
HCC, Off 90 St., by MRC Square,
New Cairo


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