1.5 t espree

We were able to do additional follow-up and confirmation of one suspected case of microcephaly because the girl was identified in Brazil, where a specific serological assay, the plaque reduction neutralisation test, and brain CT and MRI could be done. She was born in Moxico province, Angola, in August, 2017. In November, 2018, she travelled with her mother to the Microcephaly Reference Centre IPESQ (Campina Grande, Brazil), where microcephaly was diagnosed. Before November, 2018, neither the child nor her mother had travelled outside Angola. Plasma samples were taken from both on Nov 30, 2018, and tested for Zika virus and dengue virus infection with the EuroImmun IgG ELISA (London, UK). A plaque reduction neutralisation test was done according to standard protocols (appendix p 4) to quantify neutralising antibodies against Zika virus and dengue virus in both the child and her mother. CT (with a 64-section CT scanner [Philips Brilliance, UK]) and MRI (with a 1.5-T Espree [Siemens Healthcare, Germany]) were done to assess whether the child's neurological damage was consistent with congenital Zika syndrome. Ethical approval for this aspect of the study was granted by the local internal review board at IPESQ (Campina Grande, Brazil; 52888616.4.0000.5693). The mother of the child with microcephaly provided written consent on behalf of herself and her child.

A peripheral venous cannula was inserted in the upper limb. Subjects were made comfortable in a supine feet-first orientation on a Siemens 1.5 T Espree, using an extremity birdcage coil. The MRI sequences (including T2-, T1- and proton density weighted scans, Additional file 1: Table S1) were prescribed so that the bottom slice passed through the proximal aspect of the superior tibiofibular joint. The leg position and anatomical location were carefully matched at the post-treatment visit. The sequences included pre- and post-contrast T1-weighted (T1w) imaging to distinguish synovial enhancement and a multiple dynamic T1w sequence was used to collect dynamic gadolinium uptake data before, during and after the injection of contrast agent. After two dynamics (26 s), the contrast agent was administered by hand as a standard single dose of gadoterate meglumine (Dotarem, 0.2 ml/kg body weight, Guerbet), followed by a 3 ml flush of 0.9% sodium chloride. The uptake of contrast was imaged for five minutes post-injection. The post-contrast T1w fat suppressed turbo spin echo imaging was collected immediately after the dynamic series ended such that post-contrast data were collected 5 min post injection as recommended [33 (link)].

MRI scans were obtained from two different scanners. The first scanner was a Siemens Symphony 1.5T. T1‐weighted volumetric MP‐RAGE sequence was collected (TR/TE/TI/FA = 2,730/3.19/1,100/15◦, matrix = 256 × 192), consisting of 128 sagittal slices, thickness  = 1.33 mm, in‐plane resolution of 1.0 × 1.33 mm. The second scanner was a Siemens Espree 1.5 T. One 3D MP‐RAGE, T1‐weighted sequence was collected (TR/TE/TI/FA = 2,400/3.65/1,000/8°, matrix = 240 × 192), consisting of 160 sagittal slices, thickness = 1.2 mm, in‐plane resolution of 1 × 1.2 mm. Cortical reconstruction and volumetric segmentation were performed with the FreeSurfer image analysis suite version 5.3 (http://surfer.nmr.mgh.harvard.edu/). This includes segmentation of the deep gray matter volumetric structures (Fischl et al., 2009) and parcellation of the cortical surface (Desikan et al., 2006; Fischl, 2004). For this study only ROI thickness values of the ERC were calculated using methods based on ultrahigh resolution ex vivo applied to in vivo MRI (Fischl et al., 2009). Four individuals were scanned on both scanners to investigate potential bias. Mean differences in cortical thickness were generally within ±0.1 mm across the brain surface. Intraclass correlation coefficients (ICC) for ERC thickness between the two scanners were ~1.