Arechvo Anastasija, Lingman Göran, Thurn Lars, Jansson Tomas, Jokubkiene Ligita
Department of Obstetrics and Gynecology Skåne University Hospital Lund University Lund Sweden.
Department Obstetrics and Gynecology IKVL Medical Faculty Lund University Lund Sweden.
Australas J Ultrasound Med. 2021 May 25;24(3):161-172. doi: 10.1002/ajum.12246. eCollection 2021 Aug.
To assess synchronisation of MRI and US in measuring foetus phantom head structures; inter-method, intra- and inter-observer differences on biparietal diameter (BPD), head diameter, anterio-posterior head diameter (HAP) and lateral ventricle structures (VS).
Fusion Imaging (FI) has been performed by combining MRI and US simultaneously. Axial scans of 1.5 Tesla MRI on a foetus phantom were acquired and uploaded on a US machine (EPIQ 7G, Philips). A PercuNav US tracker allowed the system to recognise and display the position of the transducer. A fetal phantom tracker was used as a phantom reference. Real-time US of the phantom head was performed by synchronising the uploaded MRI images using different landmarks. Synchronisation has been assessed by taking measurements after rotating the US probe by 90. Measurements were taken by three different observers twice. Differences in measurements between MRI and US, inter-, intra-observer differences in all measurements were assessed.
BPD, HAP and VS measurements before rotation were 0.13 ± 0.06 cm, 0.46 ± 0.09 cm and 0.4 ± 0.23 cm (width) and mean 0.6 ± 0.25 cm (length) larger at MRI than at US using any number of landmarks. After US probe rotation VS were 0.3 ± 0.24 cm in width and 0.3 ± 0.27 cm in length. Intra- and inter-observer differences in all measurements were small.
FI showed good synchronisation in measurements. BPD, HAP and VS were larger at MRI than US, likely a result of the way images are generated. Intra-, inter-observer differences between measurements were small. This can be important when reporting geometric measures from FI.
评估磁共振成像（MRI）和超声（US）在测量胎儿头部模型结构时的同步性；比较两种方法之间、观察者内部和观察者之间在双顶径（BPD）、头径、前后头径（HAP）和侧脑室结构（VS）测量上的差异。
通过同时结合MRI和US进行融合成像（FI）。在胎儿头部模型上进行1.5特斯拉MRI的轴向扫描，并上传至超声设备（飞利浦EPIQ 7G）。PercuNav超声跟踪器使系统能够识别并显示换能器的位置。使用胎儿头部模型跟踪器作为模型参考。通过使用不同的标志点同步上传的MRI图像，对模型头部进行实时超声检查。通过将超声探头旋转90°后进行测量来评估同步性。由三名不同的观察者进行两次测量。评估MRI和US测量结果之间的差异，以及所有测量中观察者内部和观察者之间的差异。
使用任何数量的标志点时，旋转前MRI测量的BPD、HAP和VS分别为0.13±0.06厘米、0.46±0.09厘米和0.4±0.23厘米（宽度），平均长度比US大0.6±0.25厘米。超声探头旋转后，VS宽度为0.3±0.24厘米，长度为0.3±0.27厘米。所有测量中观察者内部和观察者之间的差异都很小。
FI在测量中显示出良好的同步性。MRI测量的BPD、HAP和VS比US大，这可能是图像生成方式的结果。测量中观察者内部和观察者之间的差异很小。这在报告FI的几何测量结果时可能很重要。
