In total, we invited 25 imaging centres to complete the survey questionnaire. We initially received responses from 23 centres (23/25, 92%); however 3 of these centres either reported that they did not perform postmortem CT for paediatric cases, or only did so on a research basis — not as part of clinical care. Therefore, we included a total of 20 centres (20/25, 80%) in our final analysis, comprising 62 different paediatric postmortem CT protocols for review.
The surveys were completed by consultant radiologists (8/20, 40%), pathologists (6/20, 30%), both radiologists and pathologists together (2/20, 10%), radiographers/technologists (2/20, 10%) and both radiologists and radiographers together (2/20, 10%).
The responses originated from several countries, including:
Europe (11/20, 55%) — United Kingdom (3), Denmark (1), Italy (1), the Netherlands (2), Poland (3) and Switzerland (1);
Oceania (4/20, 20%) — Australia (3) and New Zealand (1);
North America (4/20, 20%) — United States (3) and Canada (1); and
Asia (1/20, 5%) — Japan (1).
The findings from the survey and pooled review of imaging protocols are described next and summarised in Tables 2 and 3.
Most centres in this survey performed their imaging on a CT scanner dedicated to forensic examinations (11/20, 55%), with the remainder based in a hospital or clinic environment (9/20, 45%).
Referral indications for postmortem CT were varied, with some centres accepting all paediatric cases referred for imaging (7/20, 35%) or all infants younger than 1 year (7/20, 35%). Just less than half of all centres imaged cases referred because of a special request from the clinical team, or for a variety of specific causes (spanning a wide range of scenarios such as hanging, abuse, trauma, burn-related injuries; 5/20, 25%).
Image acquisition was mainly performed by the radiographer or technologist (13/20, 65%), although at some centres the mortuary staff (3/20, 15%), forensic physician (1/20, 5%) or pathologist (3/20, 15%) would operate the CT machinery. Image reporting was usually undertaken by a radiologist (9/20, 45%) or co-reported by a radiologist and pathologist (8/20, 40%).
There was the expected variation in the CT scanner vender and models used; however the most popular vendors included Siemens (9/20, 45%) and GE Healthcare (5/20, 25%). Almost all scanners were single-source scanners (17/20, 85%) and utilised a detector collimation of 0.5–1.0 mm (19/20, 95%).
Body coverage was variable among centres, with most performing whole-body imaging but in different ways among and within centres. Some routinely imaged the whole body in one examination (12/20, 60%, i.e. vertex to feet), whilst others also sometimes performed imaging of separate single-body regions (e.g., head, thorax, abdomen/pelvis) to make up a whole-body study, and this did not routinely include extremities (16/20, 80%). At some centres imaging of just one body region also occurred and was dependent on the referral indication (e.g., thorax for rib fractures, head/neck for traumatic brain injury).
From reviewing individual postmortem CT protocols, we noted that the following parameters were most commonly used: 120 kVp (37/62, 59.7%), 200–299 mAs (12/62, 19.4%), 0.5–0.8 pitch (29/62, 46.8%), 1-s rotation time (14/62, 22.6%) and slice thickness of ≤0.75 mm (34/62, 54.8%).
There were a variety of responses concerning scan field of view, with most protocols not specifically including this feature (19/62, 30.6%). Of those that did report the scan field of view, most protocols adjusted to patient size (attempting a scan field of view as small as possible, 18/62, 29%). Many protocols did not state matrix size (36/62, 58.1%), but where this was listed it was reported as 512 × 512 (26/62, 41.9%). The dose modulation function was stated as “off” in 50% (31/62) of cases, with the remainder of protocols either not listing this feature (7/62, 11.3%) or having this function “on” (24/62, 38.7%).
All centres reported that they routinely provided bone imaging algorithms for their postmortem CT studies, with the majority also performing soft-tissue algorithms (19/20, 95%). Many centres also provided dedicated brain (7/20, 35%) and lung (9/20, 45%) algorithms for head/neck and thoracic imaging, respectively.
In terms of multiplanar reformatting, the commonest reconstructions included coronal (17/20, 85%) and sagittal (15/20, 75%) planes. Volume-rendering reformats were provided in more than half of centres (11/20, 55%). Some centres also produced maximum- or minimum-intensity projections (6/20, 30%) or non-standard oblique reformats depending on pathology and special request (4/20, 20%).