Three-dimensional versus two-dimensional postmortem ultrasound: feasibility in perinatal death investigation

Three- and four-dimensional US techniques in antenatal screening are commonplace, but they are not routinely used for perinatal postmortem US. In this technical innovation, we performed both two-dimensional (2-D) and three-dimensional (3-D) postmortem US on 11 foetuses (mean gestation: 23 weeks; range: 15–32 weeks) to determine whether there was any benefit in 3-D over conventional 2-D methods. In one case of osteogenesis imperfecta, both 2-D and 3-D US images were non-diagnostic because of small foetal size. Of the remaining 10 foetuses, 7 were normal at imaging and autopsy, and 3 had abnormalities detected on both 2-D and 3-D US. There were no false-positive diagnoses by 2-D or 3-D US. Whilst 3-D postmortem US was a feasible technique, it did not provide additional information over 2-D US. Routine 3-D postmortem US cannot therefore be routinely recommended based on our findings

Diagnostic accuracy of postmortem ultrasound vs 1.5T postmortem MRI for non-invasive perinatal autopsies

Objectives: To determine the diagnostic accuracy of postmortem magnetic resonance imaging (PM-MRI) and postmortem ultrasound (PM-US) for perinatal autopsy in the same patient cohort, and to determine whether PM-US can provide the same anatomical information as PM-MRI. Methods: In this prospective, 5-year (July 2014–July 2019) single-center study, we performed 1.5-T PM-MRI and PM-US in an unselected cohort of perinatal deaths. The diagnostic accuracies of both modalities were calculated, using autopsy as the reference standard. As a secondary objective, the concordance rates between the two imaging modalities for the overall main diagnosis and for five anatomical regions (brain, spine, thorax, heart and abdomen) were calculated. Results: During the study period, 136 cases underwent both PM-US and PM-MRI, of which 88 (64.7%) also underwent autopsy. There was no significant difference in the rates of concordance with autopsy between the two modalities for overall diagnosis (PM-US, 86.4% (95% CI, 77.7–92.0%) vs PM-MRI, 88.6% (95% CI, 80.3–93.7%)) or in the sensitivities and specificities for individual anatomical regions. There were more non-diagnostic PM-US than PM-MRI examinations for the brain (22.8% vs 3.7%) and heart (14.7% vs 5.1%). If an ‘imaging-only’ autopsy had been performed, PM-US would have achieved the same diagnosis as 1.5-T PM-MRI in 86.8% (95% CI, 80.0–91.5%) of cases, with the highest rates of agreement being for spine (99.3% (95% CI, 95.9–99.9%)) and cardiac (97.3% (95% CI, 92.4–99.1%)) findings and the lowest being for brain diagnoses (85.2% (95% CI, 76.9–90.8%)). Conclusion: Although there were fewer non-diagnostic cases using PM-MRI than for PM-US, the high concordance rate for overall diagnosis suggests that PM-US could be used for triaging cases when PM-MRI access is limited or unavailable

Post-mortem perinatal imaging: what is the evidence?

Post-mortem imaging for the investigation of perinatal deaths is an acceptable tool amongst parents and religious groups, enabling a less invasive autopsy examination. Nevertheless, availability is scarce nationwide, and there is some debate amongst radiologists regarding the best practice and optimal protocols for performing such studies. Much of the published literature to date focusses on single centre experiences or interesting case reports. Diagnostic accuracy studies are available for a variety of individual imaging modalities (e.g. post-mortem CT, MRI, ultrasound and micro-CT), however, assimilating this information is important when attempting to start a local service.In this article, we present a comprehensive review summarising the latest research, recently published international guidelines, and describe which imaging modalities are best suited for specific indications. When the antenatal clinical findings are not supported by the post-mortem imaging, we also suggest how and when an invasive autopsy may be considered. In general, a collaborative working relationship within a multidisciplinary team (consisting of radiologists, radiographers, the local pathology department, mortuary staff, foetal medicine specialists, obstetricians and bereavement midwives) is vital for a successful service

Latest Developments in Post-Mortem Fetal Imaging

A sustained decline in parental consent rates for perinatal autopsies has driven the development of less-invasive methods for death investigation. A wide variety of imaging modalities have been developed for this purpose and include post-mortem whole body MRI, ultrasound, CT and micro-focus CT techniques. These are also vital for 'minimally invasive' methods which include potential for tissue sampling, such as image guidance for targeted biopsies and laparoscopic assisted techniques. In this article we address the range of imaging techniques currently in clinical practice, and those under development. Significant advances in high field MRI and micro-focus CT imaging show particular promise for smaller and earlier gestation fetuses. We also review how MRI biomarkers such as diffusion weighted imaging and organ volumetric analysis may aid diagnosis and image interpretation in the absence of autopsy data. 3D printing and augmented reality may help make imaging findings more accessible to parents, colleagues and trainees

Review of study reporting guidelines for clinical studies using artificial intelligence in healthcare

High-quality research is essential in guiding evidence-based care, and should be reported in a way that is reproducible, transparent and where appropriate, provide sufficient detail for inclusion in future meta-analyses. Reporting guidelines for various study designs have been widely used for clinical (and preclinical) studies, consisting of checklists with a minimum set of points for inclusion. With the recent rise in volume of research using artificial intelligence (AI), additional factors need to be evaluated, which do not neatly conform to traditional reporting guidelines (eg, details relating to technical algorithm development). In this review, reporting guidelines are highlighted to promote awareness of essential content required for studies evaluating AI interventions in healthcare. These include published and in progress extensions to well-known reporting guidelines such as Standard Protocol Items: Recommendations for Interventional Trials-AI (study protocols), Consolidated Standards of Reporting Trials-AI (randomised controlled trials), Standards for Reporting of Diagnostic Accuracy Studies-AI (diagnostic accuracy studies) and Transparent Reporting of a multivariable prediction model for Individual Prognosis Or Diagnosis-AI (prediction model studies). Additionally there are a number of guidelines that consider AI for health interventions more generally (eg, Checklist for Artificial Intelligence in Medical Imaging (CLAIM), minimum information (MI)-CLAIM, MI for Medical AI Reporting) or address a specific element such as the ‘learning curve’ (Developmental and Exploratory Clinical Investigation of Decision-AI) . Economic evaluation of AI health interventions is not currently addressed, and may benefit from extension to an existing guideline. In the face of a rapid influx of studies of AI health interventions, reporting guidelines help ensure that investigators and those appraising studies consider both the well-recognised elements of good study design and reporting, while also adequately addressing new challenges posed by AI-specific elements

Maceration determines diagnostic yield of fetal and neonatal whole body post‐mortem ultrasound

OBJECTIVES: To determine factors in non-diagnostic fetal and neonatal post-mortem ultrasound (PMUS) examinations. METHODS: All fetal and neonatal PMUS examinations were included over a 5 year study period (2014 - 2019). Non-diagnostic image quality by body parts (brain, spine, thorax, cardiac, abdomen) were recorded, and correlated with patient variables. Descriptive statistics and logistic regression analyses were performed to identify significant factors for non-diagnostic studies. RESULTS: 265 PMUS examinations were included, with median gestational age of 22 weeks (12 - 42 weeks), post-mortem weight 363g (16 - 4033g) and post-mortem interval of 8 days (0 - 39 days). Diagnostic imaging quality was achieved for 178/265 (67.2%) studies. It was high for abdominal (263/265, 99.2%); thoracic (264/265, 99.6%) and spine (265/265, 100%), but lower for brain (210/265, 79.2%) and cardiac imaging (213/265, 80.4%). Maceration was the best overall predictor for non-diagnostic imaging quality (p<0.0001). Post-mortem fetal weight was positively associated with cardiac (p =0.0133), and negatively associated with brain imaging quality (p =0.0002). Post-mortem interval was not a significant predictor. CONCLUSIONS: Fetal maceration was the best predictor for non-diagnostic PMUS, particularly for brain and heart. Fetuses with marked maceration and suspected cardiac or brain anomalies should be prioritised for post-mortem MRI

Less-invasive autopsy for early pregnancy loss

Autopsy investigations provide valuable information regarding fetal death that can assist in the parental bereavement process, and influence future pregnancies, but conventional autopsy is often declined by parents because of its invasive approach. This has led to the development of less-invasive autopsy investigations based on imaging technology to provide a more accessible and acceptable choice for parents when investigating their loss. Whilst the development and use of more conventional clinical imaging techniques (radiographs, CT, MRI, US) are well described in the literature for fetuses over 20 weeks of gestational age, these investigations have limited diagnostic accuracy in imaging smaller fetuses. Techniques such as ultra-high-field MRI (>3T) and micro-focus computed tomography have been shown to have higher diagnostic accuracy whilst still being acceptable to parents. By further developing and increasing the availability of these more innovative imaging techniques, parents will be provided with a greater choice of acceptable options to investigate their loss, which may in turn increase their uptake. We provide a narrative review focussing on the development of high-resolution, non-invasive imaging techniques to evaluate early gestational pregnancy loss

Human fetal whole-body postmortem microfocus computed tomographic imaging

Perinatal autopsy is the standard method for investigating fetal death; however, it requires dissection of the fetus. Human fetal microfocus computed tomography (micro-CT) provides a generally more acceptable and less invasive imaging alternative for bereaved parents to determine the cause of early pregnancy loss compared with conventional autopsy techniques. In this protocol, we describe the four main stages required to image fetuses using micro-CT. Preparation of the fetus includes staining with the contrast agent potassium triiodide and takes 3–19 d, depending on the size of the fetus and the time taken to obtain consent for the procedure. Setup for imaging requires appropriate positioning of the fetus and takes 1 h. The actual imaging takes, on average, 2 h 40 min and involves initial test scans followed by high-definition diagnostic scans. Postimaging, 3 d are required to postprocess the fetus, including removal of the stain, and also to undertake artifact recognition and data transfer. This procedure produces high-resolution isotropic datasets, allowing for radio-pathological interpretations to be made and long-term digital archiving for re-review and data sharing, where required. The protocol can be undertaken following appropriate training, which includes both the use of micro-CT techniques and handling of postmortem tissue

Perinatal post mortem ultrasound (PMUS): a practical approach

Declining rates of consent for standard perinatal autopsy has led to a rise in interest for postmortem imaging as an alternative, non-invasive method for investigation of childhood and perinatal deaths. Whilst much interest has focussed on cross-sectional techniques such as postmortem CT (PMCT) or MRI (PMMR), other modalities including postmortem ultrasound (PMUS) have been shown to have reasonable diagnostic accuracy rates, with the added benefit of being more readily accessible and affordable. There is little published information or formal guidance available on preparation for postmortem perinatal ultrasound, views to be obtained and differentiating normal postmortem change from potential abnormalities.This article will focus on the role of perinatal postmortem ultrasound as an alternative imaging method for non-invasive autopsy, with emphasis on imaging technique, practical considerations and commonly encountered case examples