Urologic Oncology Branch, National Cancer Institute, National Institutes of Health, Bethesda, Maryland.
Molecular Imaging Program, National Cancer Institute, National Institutes of Health, Bethesda, Maryland.
J Urol. 2018 Nov;200(5):1114-1121. doi: 10.1016/j.juro.2018.06.028. Epub 2018 Jun 22.
The relative value of rigid or elastic registration during magnetic resonance imaging/ultrasound fusion guided prostate biopsy has been poorly studied. We compared registration errors (the distance between a region of interest and fiducial markers) between rigid and elastic registration during fusion guided prostate biopsy using a prostate phantom model.
Four gold fiducial markers visible on magnetic resonance imaging and ultrasound were placed throughout 1 phantom prostate model. The phantom underwent magnetic resonance imaging and the fiducial markers were labeled as regions of interest. An experienced user and a novice user of fusion guided prostate biopsy targeted regions of interest and then the corresponding fiducial markers on ultrasound after rigid and then elastic registration. Registration errors were compared.
A total of 224 registration error measurements were recorded. Overall elastic registration did not provide significantly improved registration error over rigid registration (mean ± SD 4.87 ± 3.50 vs 4.11 ± 2.09 mm, p = 0.05). However, lesions near the edge of the phantom showed increased registration errors when using elastic registration (5.70 ± 3.43 vs 3.23 ± 1.68 mm, p = 0.03). Compared to the novice user the experienced user reported decreased registration error with rigid registration (3.25 ± 1.49 vs 4.98 ± 2.10 mm, p <0.01) and elastic registration (3.94 ± 2.61 vs 6.07 ± 4.16 mm, p <0.01).
We found no difference in registration errors between rigid and elastic registration overall but rigid registration decreased the registration error of targets near the prostate edge. Additionally, operator experience reduced registration errors regardless of the registration method. Therefore, elastic registration algorithms cannot serve as a replacement for attention to detail during the registration process and anatomical landmarks indicating accurate registration when beginning the procedure and before targeting each region of interest.
磁共振成像/超声融合引导前列腺活检中刚性或弹性配准的相对价值研究甚少。我们使用前列腺模型比较了磁共振成像/超声融合引导前列腺活检中刚性和弹性配准的配准误差（感兴趣区域和基准标记之间的距离）。
在 1 个前列腺模型中放置了 4 个在磁共振成像上可见的金基准标记。该模型接受了磁共振成像，将基准标记标记为感兴趣区域。一位经验丰富的用户和一位融合引导前列腺活检的新手用户在刚性和弹性配准后，靶向感兴趣区域，然后靶向超声上的相应基准标记。比较了配准误差。
共记录了 224 次配准误差测量值。总体而言，弹性配准并未显著改善刚性配准的配准误差（平均值±标准差 4.87±3.50 与 4.11±2.09mm，p=0.05）。然而，在使用弹性配准时，靠近模型边缘的病变显示出更大的配准误差（5.70±3.43 与 3.23±1.68mm，p=0.03）。与新手用户相比，经验丰富的用户报告刚性配准（3.25±1.49 与 4.98±2.10mm，p<0.01）和弹性配准（3.94±2.61 与 6.07±4.16mm，p<0.01）的配准误差降低。
我们没有发现刚性和弹性配准之间的配准误差总体差异，但刚性配准降低了靠近前列腺边缘的目标的配准误差。此外，无论使用何种配准方法，操作人员的经验都可以降低配准误差。因此，弹性配准算法不能替代在注册过程中对细节的关注，也不能替代在开始手术前和靶向每个感兴趣区域之前指示准确注册的解剖学标记。
