title: MRI characteristics of periaqueductal lesions in multiple sclerosis.
abstract: BACKGROUND
  In multiple sclerosis (MS), periaqueductal lesions (PAL) have been described histopathologically.
  
  
  OBJECTIVE
  We sought to investigate the frequency and characteristics of PAL on magnetic resonance images (MRIs) in patients with MS or clinically isolated syndrome (CIS).
  
  
  METHODS
  We analyzed proton density (PD)-weighted MRIs of 247 MS and 10 CIS patients. PAL were identified based on their abnormal hyperintensity and lesion shape on at least two consecutive slices. Patients with and without PAL were compared for clinical characteristics in a propensity score weighted analysis.
  
  
  RESULTS
  We identified PAL in 48/257 patients (18.7%), 34 of which had CIS or relapsing-remitting MS and 14 a progressive disease course. The shape of PAL was often circular (65%), or/and wedge-like (42%). Multi-planar image analysis in a subgroup of patients with double inversion recovery sequences revealed that 36% of PAL were periventricular lesions of the third ventricle extending towards the aqueduct. We found an association of PAL and brainstem functional system.
  
  
  CONCLUSIONS
  Although PAL may be underreported in MS, they are relatively frequent and found at all clinical stages and in CIS. They could be considered as a variant of periventricular lesions in the supratentorial midbrain and thus be useful in the diagnosis of MS.
authors: Department of Neurology, University Hospital Basel, Petersgraben 4, CH-4031 Basel, Switzerland; Medical Image Analysis Center, Schanzenstrasse 55, CH-4056 Basel, Switzerland. Electronic address: athina.papadopoulou@usb.ch.
authors: Athina
authors: A
authors: Papadopoulou
authors: Department of Neurology, University Hospital Basel, Petersgraben 4, CH-4031 Basel, Switzerland. Electronic address: yvonne.naegelin@usb.ch.
authors: Yvonne
authors: Y
authors: Naegelin
authors: Department of Neurology, University Hospital Basel, Petersgraben 4, CH-4031 Basel, Switzerland. Electronic address: katrin.weier@usb.ch.
authors: Katrin
authors: K
authors: Weier
authors: Department of Neurology, University Hospital Basel, Petersgraben 4, CH-4031 Basel, Switzerland; Medical Image Analysis Center, Schanzenstrasse 55, CH-4056 Basel, Switzerland; Department of Radiology and Nuclear Medicine, Division of Diagnostic and Interventional Neuroradiology, University Hospital Basel, Petersgraben 4, CH-4031 Basel, Switzerland. Electronic address: michael.amann@usb.ch.
authors: Michael
authors: M
authors: Amann
authors: Department of Radiology and Nuclear Medicine, Division of Diagnostic and Interventional Neuroradiology, University Hospital Basel, Petersgraben 4, CH-4031 Basel, Switzerland. Electronic address: jochen.hirsch@mevis.fraunhofer.de.
authors: Jochen
authors: J
authors: Hirsch
authors: Clinical Trial Unit, University Hospital Basel, Schanzenstrasse 55, CH-4056 Basel, Switzerland. Electronic address: stefanie.vonfelten@usb.ch.
authors: Stefanie
authors: S
authors: von Felten
authors: Department of Neurology, University Hospital Basel, Petersgraben 4, CH-4031 Basel, Switzerland. Electronic address: oezguer.yaldizli@usb.ch.
authors: Oezguer
authors: O
authors: Yaldizli
authors: Department of Neurology, University Hospital Basel, Petersgraben 4, CH-4031 Basel, Switzerland; Medical Image Analysis Center, Schanzenstrasse 55, CH-4056 Basel, Switzerland; Department of Radiology and Nuclear Medicine, Division of Diagnostic and Interventional Neuroradiology, University Hospital Basel, Petersgraben 4, CH-4031 Basel, Switzerland. Electronic address: till.sprenger@usb.ch.
authors: Till
authors: T
authors: Sprenger
authors: Medical Image Analysis Center, Schanzenstrasse 55, CH-4056 Basel, Switzerland. Electronic address: ernst-wilhelm.radue@usb.ch.
authors: Ernst Wilhelm
authors: EW
authors: Radue
authors: Department of Neurology, University Hospital Basel, Petersgraben 4, CH-4031 Basel, Switzerland. Electronic address: ludwig.kappos@usb.ch.
authors: Ludwig
authors: L
authors: Kappos
authors: Department of Neurology, University Hospital Basel, Petersgraben 4, CH-4031 Basel, Switzerland. Electronic address: achim.gass@medma.uni-heidelberg.de.
authors: Achim
authors: A
authors: Gass
keywords: Brainstem symptoms; Multiple sclerosis; Periaqueductal lesions