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Original research
A new method to statistically describe microcatheter tip position in patient-specific aneurysm models
  1. Marie Teresa Nawka,
  2. Jan-Hendrik Buhk,
  3. Susanne Gellissen,
  4. Jan Sedlacik,
  5. Jens Fiehler,
  6. Andreas Maximilian Frölich
  1. Department of Diagnostic and Interventional Neuroradiology, University Medical Centre Hamburg-Eppendorf, Hamburg, Germany
  1. Correspondence to Dr Marie Teresa Nawka, University Medical Centre Hamburg-Eppendorf, Hamburg, 20246, Germany; m.nawka{at}


Background and purpose Evidence on how to select microcatheters to facilitate aneurysm catheterization during coil embolization is sparse. We developed a new method to define microcatheter tip location inside a patient-specific aneurysm model as a 3-dimensional probability map. We hypothesized that precision and accuracy of microcatheter tip positioning depend on catheter tip shape and aneurysmal geometry.

Materials and methods Under fluoroscopic guidance two to three operators introduced differently shaped microcatheters (straight, 45°, 90°) into eight aneurysm models targeting the anatomic center of the aneurysm. Each microcatheter position was recorded with flat-panel CT, and 3-dimensional probability maps of the microcatheter tip positions were generated. Maps were assessed with histogram analyses and compared between tip shapes, aneurysm locations and operators.

Results Among a total of 530 microcatheter insertions, the precision (mean distance between catheter positions) and accuracy (mean distance to target position) were significantly higher for the 45° tip (1.10±0.64 mm, 3.81±1.41 mm, respectively) than for the 90° tip (1.27±0.57 mm, p=0.010; 4.21±1.60 mm p=0.014, respectively). Accuracy was significantly higher in posterior communicating artery aneurysms (3.38±1.20 mm) than in aneurysms of the internal carotid artery (4.56±1.54 mm, p<0.001).

Conclusion Our method can be used tostatistically describe statistically microcatheter behavior in patient-specific anatomy, which may improve the available evidence guiding microcatheter shape selection. Experience increases the ability to reach the intended position with a microcatheter (accuracy) that is also dependent on the aneurysm location, whereas catheter tip choice determines the variability of catheter tip placements versus each other (precision). Clinical validation is required.

  • aneurysm
  • catheter
  • intervention

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  • Contributors Conception/design of work – AMF, JHB. Data collection – AMF, JHB. Data analysis and interpretation – JHB, AMF, JF. Drafting the article – AMF. Critical revision of the article – SG, JS, JHB, AMF, JF. Final approval of the version to be published – JHB, AMF, JF. Agreement to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved – SG, JS, JHB, AMF, JF.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Competing interests None declared.

  • Patient consent Not required.

  • Provenance and peer review Not commissioned; externally peer reviewed.