title: Spectral presaturation inversion recovery MR imaging sequence after gadolinium injection to differentiate fibrotic scar tissue and neoplastic strands in the mesorectal fat in patients undergoing restaging of rectal carcinoma after neoadjuvant chemo- and radiation therapy.
abstract: OBJECTIVE
  To retrospectively assess the value of spectral presaturation by inversion-recovery (SPIR) magnetic resonance (MR) imaging sequence after gadolinium injection to differentiate fibrotic scar tissue and tumoral infiltration within the mesorectal fat in patients with rectal carcinoma undergoing MR restaging after neoadjuvant chemo- and radiation therapy (CRT).
  
  
  METHODS
  Forty-three consecutive patients (mean age, 65.8 years; range, 46-85 years; male:female, 29:14) with locally advanced rectal carcinoma underwent CRT followed by surgery. MR imaging was performed before and after completion of CRT by using T2-weighted turbo spin-echo and T1-weighted SPIR sequences before and after gadolinium injection, and MR images were assessed by two radiologists in consensus. Logistic regression was conducted to test the significance of the MR image findings with histology.
  
  
  RESULTS
  After CRT the disease was either limited to the rectal wall (n = 18 patients) or presented perirectal infiltration (n = 25) on histology. In 21 patients, mesorectal enhancing strands were observed. Reticular-shaped enhancing strands reaching the mesorectal fascia presented the highest correlation with tumor infiltration of the mesorectal fat (OR 130.33, 95% CI: 4.1-4220.29; logistic regression), whereas linear-shaped enhancing strands either reaching or not reaching the mesorectal fascia (OR 0.25 or 0.1, 95% CI: 0.024-2.6 or 0.01-1.07) revealed the lowest correlation.
  
  
  CONCLUSIONS
  Reticular-shaped enhancing strands on SPIR MR imaging after gadolinium injection are associated with tumor infiltration of the mesorectal fat.
authors.affiliation: Department of Radiology, Cattinara Hospital, University of Trieste, Strada di Fiume 447, 34149, Trieste, Italy.
authors.forename: Emilio
authors.initials: E
authors.lastname: Quaia
authors.forename: Veronica
authors.initials: V
authors.lastname: Ulcigrai
authors.forename: Matteo
authors.initials: M
authors.lastname: Coss
authors.forename: Luca
authors.initials: L
authors.lastname: De Paoli
authors.forename: Maja
authors.initials: M
authors.lastname: Ukmar
authors.forename: Fabrizio
authors.initials: F
authors.lastname: Zanconati
authors.forename: Alessandro
authors.initials: A
authors.lastname: De Pellegrin
authors.forename: Nicolò
authors.initials: N
authors.lastname: De Manzini
authors.forename: Maria Assunta
authors.initials: MA
authors.lastname: Cova
mesh_terms: D000273:Adipose Tissue / Q000473:pathology*; D000368:Aged; D000369:Aged, 80 and over; D059186:Chemoradiotherapy, Adjuvant; D002921:Cicatrix / Q000473:pathology*; D003287:Contrast Media / Q000008:administration & dosage*; D003937:Diagnosis, Differential; D005205:Fascia / Q000473:pathology; D005260:Female; D005355:Fibrosis / Q000473:pathology; D005682:Gadolinium; D019786:Gadolinium DTPA / Q000008:administration & dosage; D006571:Heterocyclic Compounds / Q000008:administration & dosage; D006801:Humans; D016015:Logistic Models; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008536:Meglumine / Q000008:administration & dosage; D008875:Middle Aged; D020360:Neoadjuvant Therapy; D009361:Neoplasm Invasiveness / Q000473:pathology*; D009367:Neoplasm Staging; D009942:Organometallic Compounds / Q000008:administration & dosage; D012004:Rectal Neoplasms / Q000473:pathology* / Q000628:therapy*; D012189:Retrospective Studies
chemical_list: D003287:Contrast Media; D006571:Heterocyclic Compounds; D009942:Organometallic Compounds; C062402:gadoteridol; D008536:Meglumine; D005682:Gadolinium; D019786:Gadolinium DTPA; C072417:gadoterate meglumine