Radiologic and pathological correlation of staging of rectal cancer with 3 Tesla magnetic resonance imaging.
OBJECTIVE
To assess the sensitivity and specificity of 3 Tesla magnetic resonance imaging (MRI) in the prediction of extramural spread and metastatic adenopathy in rectal carcinoma.


METHODS
This was a prospective cohort study that included forty consecutive patients with rectal carcinoma from the Department of Colorectal Surgery. Three Tesla (3T) MRI was performed on these patients after a 4-hour fast and cleansing water enema. TI-weighted and T2-weighted images were obtained with high-resolution images T2-weighted sequences through the pelvis. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of 3T MRI for prediction of metastatic adenopathy and extramural spread were calculated. The TNM staging based on MRI was compared with histopathology of the resected specimen (taken as the criterion standard).


RESULTS
In our study, sensitivity, specificity, PPV, and NPV of 3T MRI for prediction of metastatic adenopathy were 100%, 78.3%, 77.3%, and 100%, respectively. Sensitivity, specificity, PPV, and NPV of 3T MRI for prediction of extramural tumour spread were 100% and 20%, 89.7% and 100%, respectively (ie, prediction of stages T3 and above).


CONCLUSIONS
MRI allows accurate measurement of the depth of extramural tumour spread. In the assessment of metastatic adenopathy, however, MRI has a low specificity. This study shows that MRI is unlikely to miss any significant parameter in staging of rectal carcinoma. However, it has a tendency to overstage extramural spread of tumour.
Chatterjee
Parangama
P
Department of Radiodiagnosis and Imaging, Christian Medical College, Tamil Nadu, India. parangamadr@gmail.com
Eapen
Anu
A
Perakath
Benjamin
B
Singh
Ashish
A
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008207:Lymphatic Metastasis / Q000473:pathology; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009362:Neoplasm Metastasis / Q000473:pathology*; D009367:Neoplasm Staging; D010865:Pilot Projects; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012004:Rectal Neoplasms / Q000473:pathology*; D012680:Sensitivity and Specificity