Imaging Colorectal Cancers

Question 1

How are colon cancers diagnosed?

Answer 1

Colonoscopy

Double Contrast barium enema

CT/CT colonography

Question 2

For colon cancers, what investigations are used for accurate TNM staging?

Answer 2

Contrast-enhanced CT of chest, abdomen and pelvis (primary tumour and metastasis)

US and MRI of liver

Question 3

What is an apple core representative of in colon CT?

Answer 3

Colon Cancer

Question 4

What are indications for CT colonography?

Answer 4

If double barium enema not suitable (fragile patient) or incomplete colonoscopy

Question 5

What are the classifications of the ERUS for rectal cancers?

Answer 5

T1 - mucosa involved

T2 - submucosa involved

T3 - beyond muscularis proparia

T4 - more involvement

Question 6

Where is the MRI useful for rectal cancers?

Answer 6

It can depict mesorectal fascia

Evaluates all tumours

Distinguishes fibrosis from tumoural infiltration

Question 7

What are limitations of ERUS?

Answer 7

Annular restriction, large polypoidal or fungating lesions, high/low rectal lesions

Overstaging due to peritumoural reaction