[Diffusion-weighted MR imaging in patients with rectal cancer: our initial experience].
BACKGROUND
Pre-surgical characterization of post-neoadjuvant residual tumor response in patients with rectal cancer by means of an imaging technique could be useful in order to determine the therapeutic strategy or observation.


OBJECTIVE
To evaluate the role of the diffusion magnetic resonance imaging (DWMR) in the determination of residual primary tumor (RPT) or post-neoadjuvant complete pathologic response (CPR) in patients with rectal cancer (RC).


METHODS
Eighteen patients (13 males and 5 females) operated between June 2009 and September 2010 were included. The inclusion criteria were medial and low rectal tumors, with T3-T4- positive lymph nodes, defined by physical examination (rectal tact) and studies by imaging techniques (DWMR and multidetector computed tomography (MDCT). All patients received neoadjuvant treatment before surgery. Patients were later reevaluated with DWMR using visual and quantitative scales in order to measure the apparent diffusion coefficient (ADC). The results were compared to pathological anatomy (PA) as gold standard. DWMR was performed on a Siemens Avanto 1.5 T RESULTS: In the PA 15 of 18 patients presented RPT, whereas 3 patients showed a CPR. When the DWMR was used with the visual scale, RPT was detected in 14 of 15 patients, whereas all patients with RPT were detected using the quantitative scale. In those cases with complete CPR by PA, the DWMR and visual scale detected 2 of 3 patients whereas the quantitative scale in ADC detected all three cases.


CONCLUSIONS
DWMR proved to be a useful method in the determination of post-neoadjuvant RPT and CPR in patients with rectal cancer, especially when the quantitative assessment of the ADC was performed, resulting in an improvement of the results obtained by means of the qualitative visual analysis.
Servicio de Diagnóstico por Imágenes, Hospital Italiano de Buenos Aires, Ciudad Autónoma de Buenos Aires, Argentina. alberto.seehaus@hospitalitaliano.org.ar
Alberto
A
Seehaus
Carlos
C
Vacaro
Jorge
J
Ocantos
Analía
A
Varela
Lorena
L
Savluk
Guillermo
G
Ojea Quintana
Gustavo
G
Rossi
Verónica
V
Weimbaur
Juan
J
Pablo Santino
Ricardo
R
García-Mónaco
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000964:Antimetabolites, Antineoplastic / Q000008:administration & dosage; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D005472:Fluorouracil / Q000008:administration & dosage; D006801:Humans; D008297:Male; D008875:Middle Aged; D061330:Multidetector Computed Tomography; D020360:Neoadjuvant Therapy; D018365:Neoplasm, Residual; D012004:Rectal Neoplasms / Q000175:diagnosis* / Q000473:pathology / Q000628:therapy; D012189:Retrospective Studies
D000964:Antimetabolites, Antineoplastic; D005472:Fluorouracil