The assessment of irradiated bladder carcinoma using dynamic contrast-enhanced MR imaging.
OBJECTIVE
To evaluate the role of dynamic contrast-enhanced magnetic resonance imaging (DCEMRI) in distinguishing residual or recurrent tumour from radiation change in patients with bladder carcinoma.


METHODS
Forty patients with biopsy proven bladder carcinoma were imaged before and at 4 and 12 months after radiotherapy (XRT) using conventional and dynamic contrast-enhanced magnetic resonance imaging at 0.5 Tesla. An enhancement of >1.54 times above baseline at 80 s post-contrast injection proved a reliable indicator of tumour before radiotherapy and was therefore applied to the assessment of patients after XRT. Conventional MR images and dynamic enhancement profiles (DEPs) from the site of previous tumour were scored by three radiologists for the presence of tumour at 4 and 12 months after XRT. Findings were compared with cystoscopic biopsy.


RESULTS
Dynamic contrast-enhanced magnetic resonance imaging had negative predictive values of 100% and 93% for tumour recurrence at 4 and 12 months, respectively. The positive predictive values, sensitivity and specificity were 48, 100 and 48% at 4 months and 50, 80 and +76% at 12 months post XRT, respectively.


CONCLUSIONS
Dynamic contrast-enhanced magnetic resonance imaging may prove reliable in excluding the presence of persistent or recurrent tumour up to 12 months after XRT.
Dobson
M J
MJ
Department of Diagnostic Radiology, Royal Preston Hospital, Fulwood, UK.
Carrington
B M
BM
Collins
C D
CD
Ryder
W D
WD
Read
G
G
Hutchinson
C E
CE
Hawnaur
J M
JM
D003287:Contrast Media; D003937:Diagnosis, Differential; D005500:Follow-Up Studies; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D009364:Neoplasm Recurrence, Local / Q000175:diagnosis*; D018365:Neoplasm, Residual; D011237:Predictive Value of Tests; D011832:Radiation Injuries / Q000175:diagnosis*; D020266:Radiotherapy, Conformal / Q000009:adverse effects; D012680:Sensitivity and Specificity; D001749:Urinary Bladder Neoplasms / Q000175:diagnosis* / Q000532:radiotherapy*
D003287:Contrast Media