Puncturing Plaques: Relating MRI Characteristics of Peripheral Artery Lesions to Guidewire Puncture Forces

Trisha Roy, Garry Liu, Noor Shaikh, Andrew D. Dueck, Graham A. Wright

Research output: Contribution to journalArticle

8 Scopus citations

Abstract

Purpose: To test and validate magnetic resonance imaging (MRI) sequences for peripheral artery lesion characterization and relate the MRI characteristics to the amount of force required for a guidewire to puncture peripheral chronic total occlusions (CTOs) as a surrogate for immediate failure of endovascular therapy. Methods: Diseased superficial femoral, popliteal, and tibial artery segments containing 55 atherosclerotic lesions were excised from the amputated limbs of 7 patients with critical limb ischemia. The lesions were imaged at high resolution (75 μm3 voxels) with T2-weighted (T2W) and ultrashort echo time (UTE) sequences on a 7-T MR scanner. The MR images (n=15) were validated with micro-computed tomography and histology. CTOs (n=40) were classified by their MR signal characteristics as "soft" (signals indicating fat, thrombus, microchannels, or loose fibrous tissue), "hard" (collagen and/or speckled calcium signals), or "calcified" (calcified nodule signals). A 2-kg load cell advanced the back end of a 0.035-inch stiff guidewire at a fixed displacement rate (0.05 mm/s) through the CTOs, and the forces required to cross each lesion were measured. Results: T2W images showed fat as hyperintense and hardened tissue as hypointense. Calcium and thrombus appeared as a signal void in conventional MRI sequences but were easily identified in UTE images (thrombus was hyperintense and calcium hypointense). MRI accurately differentiated "hard," "soft," and "calcified" CTOs based on associated guidewire puncture force. The guidewire could not enter "calcified" CTOs (n=6) at all. "Hard" CTOs (n=9) required a significantly higher (p<0.001) puncture force of 1.71±0.51 N vs 0.43±0.36 N for "soft" CTOs (n=25). Conclusion: MRI characteristics of PAD lesions correlate with guidewire puncture forces, an important aspect of crossability. Future work will determine if clinical MR scanners can be used to predict success in peripheral vascular interventions.

Original languageEnglish (US)
Pages (from-to)35-46
Number of pages12
JournalJournal of Endovascular Therapy
Volume24
Issue number1
DOIs
StatePublished - Feb 2017

Keywords

  • angioplasty
  • atherosclerosis
  • calcification
  • chronic total occlusion
  • displacement force
  • endovascular treatment/therapy
  • ex vivo study
  • guidewire
  • histology
  • imaging
  • magnetic resonance imaging
  • microCT
  • peripheral artery disease
  • plaque morphology
  • popliteal artery
  • superficial femoral artery
  • tibial artery
  • ultrashort echo time sequence

ASJC Scopus subject areas

  • Surgery
  • Radiology Nuclear Medicine and imaging
  • Cardiology and Cardiovascular Medicine

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