title: The combined use of conventional MRI and MR spectroscopic imaging increases the diagnostic accuracy in amyotrophic lateral sclerosis.
abstract: OBJECTIVE
  We aimed to assess, in amyotrophic lateral sclerosis (ALS), the diagnostic accuracy of the combined use of conventional MRI signal changes (namely, hypointensity of the precentral cortex and hyperintensity of the corticospinal tracts on T2-weighted images), and N-Acetyl-Aspartate (NAA) reduction in the motor cortex at Magnetic Resonance Spectroscopy (MRS), which are affected by limited diagnostic accuracy when used separately.
  
  
  METHODS
  T2-hypointensity and NAA/(Choline+Creatine) ratio of the precentral gyrus and T2-hyperintensity of the corticospinal tracts were measured in 84 ALS patients and 28 healthy controls, using a Region-of-Interest approach. Sensitivity and specificity values were calculated using Fisher stepwise discriminant analysis, and cross-validated using the leave-one-out method.
  
  
  RESULTS
  Precentral gyrus T2 signal intensity (p<10(-4)) and NAA peak (p<10(-6)) were significantly reduced in patients, and their values did not correlate significantly to each other both in patients and controls, while no significant differences were obtained in terms of T2-hyperintensity of the corticospinal tract. Sensitivity and specificity of the two discriminant variables, taken alone, were 71.4% and 75.0%, for NAA peak, and 63.1% and 71.4% for T2-hypointensity, respectively. When using these two variables in combination, a significant increase in sensitivity (78.6%) and specificity (82.1%) was achieved.
  
  
  CONCLUSIONS
  Precentral gyrus T2-hypointensity and NAA peak are not significantly correlated in ALS patients, suggesting that they reflect relatively independent phenomena. The combined use of these measures improves the diagnostic accuracy of MRI in ALS diagnosis.
authors.affiliation: Department of Advanced Biomedical Sciences, University "Federico II", Naples, Italy.
authors.forename: Amedeo
authors.initials: A
authors.lastname: Cervo
authors.affiliation: Department of Advanced Biomedical Sciences, University "Federico II", Naples, Italy. Electronic address: siriococozza@hotmail.it.
authors.forename: Sirio
authors.initials: S
authors.lastname: Cocozza
authors.affiliation: Department of Neurosciences, Reproductive Sciences and Odontostomatology, University "Federico II", Naples, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Saccà
authors.affiliation: Department of Advanced Biomedical Sciences, University "Federico II", Naples, Italy.
authors.forename: Sara M D A
authors.initials: SMDA
authors.lastname: Giorgio
authors.affiliation: Department of Neurosciences, Reproductive Sciences and Odontostomatology, University "Federico II", Naples, Italy.
authors.forename: Vincenzo Brescia
authors.initials: VB
authors.lastname: Morra
authors.affiliation: Department of Advanced Biomedical Sciences, University "Federico II", Naples, Italy.
authors.forename: Enrico
authors.initials: E
authors.lastname: Tedeschi
authors.affiliation: Department of Neurosciences, Reproductive Sciences and Odontostomatology, University "Federico II", Naples, Italy.
authors.forename: Angela
authors.initials: A
authors.lastname: Marsili
authors.affiliation: Department of Neurosciences, Reproductive Sciences and Odontostomatology, University "Federico II", Naples, Italy.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Vacca
authors.affiliation: U.O.C. Neuroﬁsiopatologia, PO S. Gennaro ASL Napoli 1, Naples, Italy.
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Palma
authors.affiliation: Department of Advanced Biomedical Sciences, University "Federico II", Naples, Italy.
authors.forename: Arturo
authors.initials: A
authors.lastname: Brunetti
authors.affiliation: Biostructure and Bioimaging Institute, National Research Council, Naples, Italy.
authors.forename: Mario
authors.initials: M
authors.lastname: Quarantelli
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000690:Amyotrophic Lateral Sclerosis / Q000175:diagnosis* / Q000378:metabolism; D001224:Aspartic Acid / Q000031:analogs & derivatives / Q000378:metabolism; D002540:Cerebral Cortex / Q000378:metabolism / Q000473:pathology*; D002794:Choline / Q000378:metabolism; D003401:Creatine / Q000378:metabolism; D005260:Female; D005625:Frontal Lobe / Q000378:metabolism / Q000473:pathology; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging / Q000379:methods*; D011712:Pyramidal Tracts / Q000378:metabolism / Q000473:pathology; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012680:Sensitivity and Specificity
chemical_list: D001224:Aspartic Acid; C000179:N-acetylaspartate; D003401:Creatine; D002794:Choline
keywords: Amyotrophic lateral sclerosis; Conventional MRI; Hyperintensity; Hypointensity; Magnetic Resonance Spectroscopy; Motor cortex