Many medical interventions involve ultrasound based imaging systems to safely localize and navigate instruments into the patient body. To facilitate visual tracking of the instruments, we investigate the techniques and methodologies best suited for solving the problem of needle localization in ultrasound images. We propose a robust procedure that automatically determines the position of a needle in 2D ultrasound images. Such a task is decomposed into the localization of the needle axis and its tip. A first estimation of the axis position is computed with the help of multiple position sensors, including one embedded in the transducer and another in the needle. Based on this, the needle axis is computed using a RANSAC algorithm. The tip is detected by analyzing the intensity along the axis and a Kalman filter is added to compensate for measurement uncertainties. The algorithms were experimentally verified on real ultrasound images acquired by a 2D scanner scanning a portion of a cryogel phantom that contained a thin metallic needle. The experiments shows that the algorithms are capable of detecting a needle at millimeter accuracy.The computational time of the order of milliseconds permits real time needle localization.
| Identifer | oai:union.ndltd.org:UPSALLA1/oai:DiVA.org:kth-180454 |
| Date | January 2015 |
| Creators | Demeulemeester, Kilian |
| Publisher | KTH, Skolan för datavetenskap och kommunikation (CSC) |
| Source Sets | DiVA Archive at Upsalla University |
| Language | English |
| Detected Language | English |
| Type | Student thesis, info:eu-repo/semantics/bachelorThesis, text |
| Format | application/pdf |
| Rights | info:eu-repo/semantics/openAccess |
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