OBJECTIVES: To assess the value of MRI and @entity353 ( @entity353 ) for diagnosing local @entity5 regrowth during follow-up of organ preservation treatment after chemoradiotherapy for @entity5 . METHODS: Seventy-two @entity1 underwent organ preservation treatment (chemoradiotherapy + transanal endoscopic microsurgery or "wait-and-see") and were followed with MRI including @entity353 (1.5  T) every 3 -months during the first year and 6  months during following years. Two readers scored each MRI for local regrowth using a confidence level, first on standard MRI, then on standard MRI+ @entity353 . Histology and clinical follow-up were the standard reference. Receiver operating characteristic curves were constructed and areas under the curve (AUC) and corresponding accuracy figures calculated on a per-scan basis. RESULTS: Four hundred and forty MRIs were assessed. Twelve @entity1 developed local regrowth. AUC/sensitivity/specificity for standard MRI were 0.95/58  %/98  % (R1) and 0.96/58  % /100  % (R2). For standard MRI+ @entity353 , these numbers were 0.86/75  %/97  % (R1) and 0.98/75  %/100  % (R2). After adding @entity353 , the number of equivocal scores decreased from 22 to 7 (R1) and from 40 to 20 (R2). CONCLUSIONS: Although there was no overall improvement in diagnostic performance in terms of AUC, adding @entity353 improved the sensitivity of MRI for diagnosing local @entity5 regrowth and lowered the rate of equivocal MRIs. KEY POINTS:     @entity353 improves sensitivity for detecting local @entity5 regrowth after organ preservation treatment.     In particular, @entity353 can aid in detecting small local recurrence.     @entity353 reduces the number of equivocal scores.

MRI and diffusion-weighted MRI to diagnose a local XXXX regrowth during long-term follow-up of @entity5 @entity1 treated with organ preservation after chemoradiotherapy.

@entity5 :: ('MESH:D009369', 'Disease') :: ['rectal cancer', 'tumour'] @entity1 :: ('9606', 'Species') :: ['patients'] @entity353 :: ('MESH:D015431', 'Disease') :: ['DWI', 'diffusion-weighted imaging']
@entity5 :: (MESH:D009369,Disease) :: ['tumour']
