title: Suspected early or mild chronic pancreatitis: enhancement patterns on gadolinium chelate dynamic MRI. Magnetic resonance imaging.
abstract: OBJECTIVE
  To assess whether measuring the pattern of pancreatic enhancement on gadolinium chelate dynamic magnetic resonance imaging (MRI) is helpful for diagnosis of suspected early or mild chronic pancreatitis.
  
  
  METHODS
  In this retrospective study, 24 patients with suspected early or mild chronic pancreatitis, classified by imaging criteria of equivocal chronic pancreatitis (ultrasound, computed tomography [CT] or ERCP) grading, had dynamic MRI that included unenhanced, arterial dominant, early venous, and late venous phases of contrast enhancement. Twenty patients without pancreatic diseases also had the dynamic sequence as a control group. The signal intensity was measured at the pancreatic head, body, and tail on all phases, and for each, the signal intensity ratio (SIR, the signal intensity in postcontrast divided by that in precontrast) was calculated. Two radiologists independently reviewed the images of the patients with suspected early or mild chronic pancreatitis for pancreatic morphologic abnormalities without knowing the results of signal intensity measurements.
  
  
  RESULTS
  On unenhanced images, there was no significant difference of signal intensity between control and pancreatitis groups (P < 0.05). In the pancreatitis group, but not in the control group, the unenhanced signal intensity of the pancreatic head and body were significantly higher than that of the tail (P < 0.05). In the control group, the greatest enhancement (highest SIR) after injection was in the arterial phase (1.89 +/- 0.31), significantly higher than that in the early venous phase (1.68 +/- 0.17, P < 0.01) and in the late venous phase (1.61 +/- 0.15, P < 0.001). The pancreatitis group, however, had an arterial phase SIR (1.65 +/- 0.23) that was significantly lower than its early venous phase SIR (1.75 +/- 0.22, P < 0.05) and lower than the arterial phase SIR of the control group (P < 0.01). The presence of an SIR less than 1.73 in the arterial phase and/or a delayed peak enhancement after contrast agent administration had a sensitivity and specificity of diagnosing early or mild chronic pancreatitis of 92% and 75%, respectively. This sensitivity was significantly higher than the sensitivity of 50% for diagnosis based on morphologic abnormalities (P < 0.05).
  
  
  CONCLUSIONS
  Measuring pancreatic signal intensity on gadolinium chelate dynamic MRI is helpful for diagnosing early or mild chronic pancreatitis, especially before apparent pancreatic morphologic or signal intensity changes are present.
authors.affiliation: Department of Radiology, Thomas Jefferson University Hospital, Philadelphia, Pennsylvania 19107, USA.
authors.forename: Xiao-Ming
authors.initials: XM
authors.lastname: Zhang
authors.forename: Hongyu
authors.initials: H
authors.lastname: Shi
authors.forename: Laurence
authors.initials: L
authors.lastname: Parker
authors.forename: Masako
authors.initials: M
authors.lastname: Dohke
authors.forename: George A
authors.initials: GA
authors.lastname: Holland
authors.forename: Donald G
authors.initials: DG
authors.lastname: Mitchell
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D002908:Chronic Disease; D005260:Female; D005682:Gadolinium; D006801:Humans; D007089:Image Enhancement; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D010195:Pancreatitis / Q000473:pathology*; D012189:Retrospective Studies; D013997:Time Factors
chemical_list: D005682:Gadolinium