Fast automatic segmentation of thalamic nuclei from MP2RAGE acquisition at 7 Tesla

Ritobrato Datta, Micky K. Bacchus, Dushyant Kumar, Mark A. Elliott, Aditya Rao, Sudipto Dolui, Ravinder Reddy, Brenda L. Banwell, Manojkumar Saranathan

Research output: Contribution to journalArticlepeer-review

3 Scopus citations

Abstract

Purpose: Thalamic nuclei are largely invisible in conventional MRI due to poor contrast. Thalamus Optimized Multi-Atlas Segmentation (THOMAS) provides automatic segmentation of 12 thalamic nuclei using white-matter-nulled (WMn) Magnetization Prepared Rapid Gradient Echo (MPRAGE) sequence at 7T, but increases overall scan duration. Routinely acquired, bias-corrected Magnetization Prepared 2 Rapid Gradient Echo (MP2RAGE) sequence yields superior tissue contrast and quantitative T1 maps. Application of THOMAS to MP2RAGE has been investigated in this study. Methods: Eight healthy volunteers and five pediatric-onset multiple sclerosis patients were recruited at Children's Hospital of Philadelphia and scanned at Siemens 7T with WMn-MPRAGE and multi-echo-MP2RAGE (ME-MP2RAGE) sequences. White-matter-nulled contrast was synthesized (MP2-SYN) from T1 maps from ME-MP2RAGE sequence. Thalamic nuclei were segmented using THOMAS joint label fusion algorithm from WMn-MPRAGE and MP2-SYN datasets. THOMAS pipeline was modified to use majority voting to segment bias corrected T1-weighted uniform (MP2-UNI) images. Thalamic nuclei from MP2-SYN and MP2-UNI images were evaluated against corresponding nuclei obtained from WMn-MPRAGE images using dice coefficients, volume similarity indices (VSIs) and distance between centroids. Results: For MP2-SYN, dice > 0.85 and VSI > 0.95 was achieved for five larger nuclei and dice > 0.6 and VSI > 0.7 was achieved for seven smaller nuclei. The dice and VSI were slightly higher, whereas the distance between centroids were smaller for MP2-SYN compared to MP2-UNI, indicating improved performance using the MP2-SYN image. Conclusions: THOMAS algorithm can successfully segment thalamic nuclei in MP2RAGE images with essentially equivalent quality as WMn-MPRAGE, widening its applicability in studies focused on thalamic involvement in aging and disease.

Original languageEnglish (US)
Pages (from-to)2781-2790
Number of pages10
JournalMagnetic Resonance in Medicine
Volume85
Issue number5
DOIs
StatePublished - May 2021

Keywords

  • MP2RAGE
  • multiple sclerosis
  • segmentation
  • thalamic nuclei
  • thalamus

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging

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