title: Dynamic MRI for distinguishing high-flow from low-flow peripheral vascular malformations.
abstract: OBJECTIVE
  The purpose of our study was to assess the usefulness of dynamic MRI in distinguishing high-flow vascular malformations from low-flow vascular malformations, which do not need angiography for treatment.
  
  
  METHODS
  Between September 2001 and January 2003, 16 patients who underwent conventional and dynamic MRI had peripheral vascular malformations (six high- and 10 low-flow). The temporal resolution of dynamic MRI was 5 sec. Time intervals between beginning of enhancement of an arterial branch in the vicinity of a lesion in the same slice and the onset of enhancement in the lesion were calculated. We defined these time intervals as "artery-lesion enhancement time." Time intervals between the onset of enhancement in the lesion and the time of the maximal percentage of enhancement above baseline of the lesion within 120 sec were measured. We defined these time intervals as "contrast rise time" of the lesion. Diagnosis of the peripheral vascular malformations was based on angiographic or venographic findings.
  
  
  RESULTS
  The mean artery-lesion enhancement time of the high-flow vascular malformations (3.3 sec [range, 0-5 sec]) was significantly shorter than that of the low-flow vascular malformations (8.8 sec [range, 0-20 sec]) (Mann-Whitney test, p < 0.05). The mean maximal lesion enhancement time of the high-flow vascular malformations (5.8 sec [range, 5-10 sec]) was significantly shorter than that of the low-flow vascular malformations (88.4 sec [range, 50-100 sec]) (Mann-Whitney test, p < 0.01).
  
  
  CONCLUSIONS
  Dynamic MRI is useful for distinguishing high-flow from low-flow vascular malformations, especially when the contrast rise time of the lesion is measured.
authors.affiliation: Department of Radiology, Showa University School of Medicine, Tokyo, Japan. yogiya@qd5.so-net.ne.jp
authors.forename: Yoshimitsu
authors.initials: Y
authors.lastname: Ohgiya
authors.forename: Toshi
authors.initials: T
authors.lastname: Hashimoto
authors.forename: Takehiko
authors.initials: T
authors.lastname: Gokan
authors.forename: Shouji
authors.initials: S
authors.lastname: Watanabe
authors.forename: Masayoshi
authors.initials: M
authors.lastname: Kuroda
authors.forename: Masanori
authors.initials: M
authors.lastname: Hirose
authors.forename: Seishi
authors.initials: S
authors.lastname: Matsui
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Nobusawa
authors.forename: Takashi
authors.initials: T
authors.lastname: Kitanosono
authors.forename: Hirotsugu
authors.initials: H
authors.lastname: Munechika
mesh_terms: D000293:Adolescent; D000328:Adult; D000792:Angiography; D001165:Arteriovenous Malformations / Q000175:diagnosis*; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D016491:Peripheral Vascular Diseases / Q000175:diagnosis*; D011446:Prospective Studies; D018709:Statistics, Nonparametric