title: Optimising diffusion-weighted MR imaging for demonstrating pancreatic cancer: a comparison of respiratory-triggered, free-breathing and breath-hold techniques.
abstract: OBJECTIVE
  To compare respiratory-triggered, free-breathing, and breath-hold DWI techniques regarding (1) image quality, and (2) signal intensity (SI) and ADC measurements in pancreatic ductal adenocarcinoma (PDAC).
  
  
  METHODS
  Fifteen patients with histopathologically proven PDAC underwent DWI prospectively at 1.5 T (b = 0, 50, 300, 600 and 1,000 s/mm(2)) with the three techniques. Two radiologists, independently and blindly, assigned total image quality scores [sum of rating diffusion images (lesion detection, anatomy, presence of artefacts) and ADC maps (lesion characterisation, overall image quality)] per technique and ranked them. The lesion SI, signal-to-noise ratio, mean ADC and coefficient of variation (CV) were compared.
  
  
  RESULTS
  Total image quality scores for respiratory-triggered, free-breathing and breath-hold techniques were 17.9, 16.5 and 17.1 respectively (respiratory-triggered was significantly higher than free-breathing but not breath-hold). The respiratory-triggered technique had a significantly higher ranking. Lesion SI on all b-values and signal-to-noise ratio on b300 and b600 were significantly higher for the respiratory-triggered technique. For respiratory-triggered, free-breathing and breath-hold techniques the mean ADCs were 1.201, 1.132 and 1.253 × 10(-3) mm(2)/s, and mean CVs were 8.9, 10.8 and 14.1 % respectively (respiratory-triggered and free-breathing techniques had a significantly lower mean CV than the breath-hold technique).
  
  
  CONCLUSIONS
  In both analyses, respiratory-triggered DWI showed superiority and seems the optimal DWI technique for demonstrating PDAC.
  
  
  CONCLUSIONS
  • Diffusion-weighted magnetic resonance imaging is increasingly used to detect pancreatic cancer                                                  • Images are acquired using various breathing techniques and multiple b-values                                                  • Breathing techniques used: respiratory-triggering, free-breathing and breath-hold                                                  • Respiratory-triggering seems the optimal breathing technique for demonstrating pancreatic cancer.
authors.affiliation: Division of Medical Imaging and Technology, Department of Clinical Science, Intervention and Technology (CLINTEC), Karolinska Institutet, Karolinska University Hospital, 141 86, Stockholm, Sweden. nikolaos.kartalis@karolinska.se
authors.forename: Nikolaos
authors.initials: N
authors.lastname: Kartalis
authors.forename: Louiza
authors.initials: L
authors.lastname: Loizou
authors.forename: Nick
authors.initials: N
authors.lastname: Edsborg
authors.forename: Ralf
authors.initials: R
authors.lastname: Segersvärd
authors.forename: Nils
authors.initials: N
authors.lastname: Albiin
mesh_terms: D000230:Adenocarcinoma / Q000175:diagnosis*; D062485:Breath Holding; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010190:Pancreatic Neoplasms / Q000175:diagnosis*; D011446:Prospective Studies; D012119:Respiration