title: Diffusion-weighted magnetic resonance imaging for detecting lymph node metastasis of rectal cancer.
abstract: BACKGROUND
  Preoperative diagnosis of lymph node metastasis is important in determining the optimal therapy for rectal cancer. It has been shown that diffusion-weighted magnetic resonance imaging (DWI) is a useful tool for detecting malignant tumors.
  
  
  METHODS
  One hundred twenty-nine consecutive patients with rectal cancer were examined with DWI + conventional (T1-weighted and T2-weighted) MRI and computed tomography (CT). All 129 patients underwent rectal resection with total mesorectal excision. Findings on DWI + conventional MRI and CT were compared with those from histopathologic examinations.
  
  
  RESULTS
  Fifty-nine (46%) patients had metastatic lymph nodes on histopathologic examinations. Two hundred twenty (18%) of 1,250 lymph nodes were pathologically positive for tumor metastasis. The overall patient-based sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of DWI + conventional MRI were 93, 81, 81, 93, and 87%, respectively. Corresponding values of CT were 73, 79, 74, 77, and 76%, respectively. The overall node-based sensitivity, specificity, PPV, NPV, and accuracy of DWI + conventional MRI were 97, 81, 52, 99, and 84%, respectively. Corresponding values of CT were 86, 80, 48, 96, and 81%, respectively.
  
  
  CONCLUSIONS
  DWI + conventional MRI is effective for the detection of lymph node metastasis and useful for selection of the optimal therapy for rectal cancer.
authors.affiliation: Department of Gastroenterological Surgery, The Tazuke-Kofukai Medical Research Institute, Kitano Hospital, 2-4-20, Ohgimachi, Kita-ku, Osaka, 530-8480, Japan.
authors.forename: Yo
authors.initials: Y
authors.lastname: Mizukami
authors.forename: Shugo
authors.initials: S
authors.lastname: Ueda
authors.forename: Akiyoshi
authors.initials: A
authors.lastname: Mizumoto
authors.forename: Tetsuro
authors.initials: T
authors.lastname: Sasada
authors.forename: Ryosuke
authors.initials: R
authors.lastname: Okumura
authors.forename: Shigene
authors.initials: S
authors.lastname: Kohno
authors.forename: Arimichi
authors.initials: A
authors.lastname: Takabayashi
mesh_terms: D000230:Adenocarcinoma / Q000175:diagnosis* / Q000401:mortality / Q000556:secondary* / Q000628:therapy; D000368:Aged; D000369:Aged, 80 and over; D001707:Biopsy, Needle; D015331:Cohort Studies; D003082:Colectomy / Q000009:adverse effects / Q000379:methods / Q000401:mortality; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D007564:Japan; D008198:Lymph Nodes / Q000473:pathology*; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D020360:Neoadjuvant Therapy; D009364:Neoplasm Recurrence, Local / Q000401:mortality* / Q000473:pathology; D009367:Neoplasm Staging; D011237:Predictive Value of Tests; D011300:Preoperative Care / Q000379:methods; D011379:Prognosis; D012004:Rectal Neoplasms / Q000175:diagnosis* / Q000401:mortality / Q000628:therapy; D018570:Risk Assessment; D015996:Survival Rate; D014057:Tomography, X-Ray Computed / Q000379:methods