title: Accuracy of magnetic resonance parkinsonism index for differentiation of progressive supranuclear palsy from probable or possible Parkinson disease.
abstract: BACKGROUND
  Combined measurements on conventional magnetic resonance imaging (MRI), such as midbrain area/pons area or magnetic resonance parkinsonism index (MRPI) (pons area/midbrain area × middle cerebellar peduncle width/superior cerebellar peduncle width), have been proposed as powerful tools in the differential diagnosis between progressive supranuclear palsy (PSP) and Parkinson disease (PD). In this study, we evaluated the accuracy of MRPI, compared with midbrain/pons ratio, in distinguishing PSP from probable and possible PD.
  
  
  METHODS
  Forty-two PSP patients, 170 probable PD patients, 132 possible PD patients, and 38 control subjects underwent MRI and, for each patient, midbrain/pons ratio and MRPI were calculated.
  
  
  RESULTS
  Midbrain/pons ratio showed low accuracy in distinguishing PSP patients from those with probable PD (92.9% sensitivity; 85.3% specificity; 86.8% diagnostic accuracy) or those with possible PD (88.1% sensitivity, 88.3% specificity, and 88.2% diagnostic accuracy) and control subjects (97.6% sensitivity, 92.1% specificity, and 95% diagnostic accuracy). By contrast, MRPI showed higher accuracy to distinguish PSP from probable PD (100% sensitivity, 99.4% specificity, and 99.5% diagnostic accuracy), from possible PD (100% sensitivity, 99.2% specificity, and 99.4% diagnostic accuracy), and from control subjects (sensitivity, specificity, and diagnostic accuracy of 100%).
  
  
  CONCLUSIONS
  Our study confirms that MRPI is a more accurate measure than midbrain/pons ratio for differentiation of patients with PSP from those with probable and possible PD.
authors.affiliation: Institute of Neurology, University Magna Graecia, Germaneto, Catanzaro, Italy.
authors.forename: Maurizio
authors.initials: M
authors.lastname: Morelli
authors.forename: Gennarina
authors.initials: G
authors.lastname: Arabia
authors.forename: Maria
authors.initials: M
authors.lastname: Salsone
authors.forename: Fabiana
authors.initials: F
authors.lastname: Novellino
authors.forename: Laura
authors.initials: L
authors.lastname: Giofrè
authors.forename: Rosina
authors.initials: R
authors.lastname: Paletta
authors.forename: Demetrio
authors.initials: D
authors.lastname: Messina
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Nicoletti
authors.forename: Francesca
authors.initials: F
authors.lastname: Condino
authors.forename: Olivier
authors.initials: O
authors.lastname: Gallo
authors.forename: Pierluigi
authors.initials: P
authors.lastname: Lanza
authors.forename: Aldo
authors.initials: A
authors.lastname: Quattrone
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001931:Brain Mapping; D001933:Brain Stem / Q000473:pathology; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000175:diagnosis*; D012372:ROC Curve; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D013494:Supranuclear Palsy, Progressive / Q000175:diagnosis*