title: Echoplanar MR imaging for ultrafast detection of brain lesions.
abstract: OBJECTIVE
  We retrospectively evaluated the use of echo-planar imaging for ultrafast detection of brain lesions.
  
  
  METHODS
  In our retrospective study, 61 patients were imaged with the following echo-planar sequences: single-shot proton density-weighted, single-shot T2-weighted, single-shot T2-weighted high-resolution, multishot proton density-weighted, and multishot T2-weighted. Lesions revealed in these patients ranged from 0.5 to 12.0 cm (mean, 3.7 cm) and were the result of tumor (n = 16), stroke (n = 21), demyelination (n = 18), and toxoplasmosis (n = 2). Four patients had scans with normal findings. Two neuroradiologists who were unaware of pertinent clinical data reviewed the images. The images were retrospectively compared with conventional spin-echo images for diagnosis, sensitivity of lesion detection, and qualitative criteria: subjective image quality, gray and white matter differentiation, lesion conspicuity, delineation of lesion borders, and artifacts. (Artifacts included those caused by motion, susceptibility, pulsation, and ghosting.) Quantitative criteria, including signal-to-noise and signal difference-to-noise measurements, were also evaluated in 40 lesions.
  
  
  RESULTS
  Sensitivity for lesion detection was 97% for single-shot echo-planar T2-weighted MR images and 100% for multishot echo-planar T2-weighted MR images. Single-shot echo-planar proton density-weighted MR images had the highest signal-to-noise ratio (91.2+/-19.3). Echo-planar T2-weighted MR images had the highest signal difference-to-noise (33.8+/-22.9). Echo-planar sequences were superior to spin-echo sequences regarding motion and pulsation artifacts. Spin-echo sequences lacked susceptibility and ghosting artifacts, and were superior in lesion conspicuity and delineation of lesion borders.
  
  
  CONCLUSIONS
  In this study, echo-planar sequences were as sensitive as conventional spin-echo imaging for the diagnostic assessment of lesions. Echo-planar sequences had a strikingly shorter acquisition time and substantially reduced motion and pulsation artifacts. Echo-planar sequences may be a useful diagnostic tool for use in claustrophobic and unstable patients.
authors.affiliation: Department of Radiology, SCC, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA.
authors.forename: M R
authors.initials: MR
authors.lastname: Patel
authors.forename: B
authors.initials: B
authors.lastname: Siewert
authors.forename: R
authors.initials: R
authors.lastname: Klufas
authors.forename: N
authors.initials: N
authors.lastname: Yousuf
authors.forename: R R
authors.initials: RR
authors.lastname: Edelman
authors.forename: S
authors.initials: S
authors.lastname: Warach
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016477:Artifacts; D001921:Brain / Q000473:pathology; D001927:Brain Diseases / Q000175:diagnosis*; D001932:Brain Neoplasms / Q000175:diagnosis; D017352:Echo-Planar Imaging / Q000295:instrumentation / Q000379:methods / Q000706:statistics & numerical data; D005188:False Negative Reactions; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D013997:Time Factors; D016781:Toxoplasmosis, Cerebral / Q000175:diagnosis