Post-mortem skeletal surveys in suspected non-accidental injury.

AIM: To evaluate potential differences between live (LSS) and post-mortem skeletal surveys (PMSS) in cases of non-accidental injury (NAI). MATERIALS AND METHODS: All skeletal surveys (SS) performed for suspected NAI over a 5 year period were retrospectively reviewed. Demographic details, injuries obtained, artefacts, and radiographic difficulties encountered during LSS and PMSS were recorded. RESULTS: Of 195 surveys performed, there were significantly fewer positive PMSS (11/128; 8.6%) than LSS (16/67; 23.8%), but no difference between the actual injuries encountered. Of those who had a positive SS, dead children were significantly younger (mean age 2.6 ± 3.4 months old) than live children (7.8 ± 6.9 months old; p < 0.05). Thirty-six percent of all contemporary digital radiographs contained artefacts, particularly in PMSS (599/1504; 39.8%) compared to LSS (269/904: 29.7%; p < 0.001), which were mostly patient identification labels (55.1 versus 21.6%; p < 0.001). PMSS demonstrated death-related radiographic complications in 10.6% of cases. CONCLUSION: Radiographic imaging in deceased children is not easy, and yields significant artefacts, which may hamper image interpretation. A technique for obtaining multiple views of a limb in fixed flexion deformity to maximize the diagnostic potential is described. Careful consideration of these factors would maximize the diagnostic yield in this unique patient population.

Nutcracker and SMA syndromes: What is the normal SMA angle in children?

OBJECTIVE: The nutcracker and superior mesenteric artery (SMA) syndromes are rare conditions where the left renal vein or duodenum may be compressed by an unusually acute angle between the SMA and aorta, although the normal angle in children is unknown. We measured the SMA angle to define the normal range in children. METHODS: We retrospectively measured SMA angles, left renal vein (LRV) distance, and duodenal distance (DD) in 205 consecutive pediatric abdominal CT. Total and visceral intra-abdominal fat at the level of the umbilicus were also assessed. RESULTS: Mean SMA angle was 45.6±19.6° (range 10.6-112.9°), mean LRV distance was 8.6±3.9mm (range 2.0-28.6mm) and mean DD was 11.3±4.8mm (range 3.6-35.3mm). There was a significant but weak correlation between %visceral fat volume (%VF) and SMA angle (R=0.30; p<0.001), LRV distance (R=0.37, p<0.001) and DD (R=0.32; p<0.001). CONCLUSION: There is a wide range of SMA angle, LRV and DD in normal children, which correlated weakly with visceral fat volume. Using a definition of SMA angle <25° would diagnose 9.3% of asymptomatic children with nutcracker syndrome, and using a DD definition of <8mm would diagnose 20% with SMA compression. Our findings suggest exercising caution when attributing these rare syndromes to an absolute SMA angle.

Minimally-invasive fetal autopsy using magnetic resonance imaging and percutaneous organ biopsies: clinical value and comparison to conventional autopsy.

OBJECTIVES: Autopsy is an important investigation following fetal death or termination for fetal abnormality. Postmortem magnetic resonance imaging (MRI) can provide macroscopic information of comparable quality to that of conventional autopsy in the event of perinatal death. It does not provide tissue for histological examination, which may limit the quality of counseling for recurrence risks and elucidation of the cause of death. We sought to examine the comparability and clinical value of a combination of postmortem MRI and percutaneous fetal organ biopsies (minimally invasive autopsy (MIA)) with conventional fetal autopsy. METHODS: Forty-four fetuses underwent postmortem MRI and attempted percutaneous biopsy (using surface landmarks) of major fetal organs (liver, lung, heart, spleen, kidney, adrenal and thymus) following fetal death or termination for abnormality, prior to conventional autopsy, which was considered the 'gold standard'. We compared significant findings of the two examinations for both diagnostic information and clinical significance. Ancillary investigations (such as radiographs and placental histology) were regarded as common to the two forms of autopsy. RESULTS: In 21 cases conventional autopsy provided superior diagnostic information to that of MIA. In two cases the MIA provided superior diagnostic information to that of conventional autopsy, when autolysis prevented detailed examination of the fetal brain. In the remaining 21 cases, conventional autopsy and MIA provided equivalent diagnostic information. With regard to clinical significance, however, in 32 (72.7%) cases, the MIA provided information of at least equivalent clinical significance to that of conventional autopsy. In no case did the addition of percutaneous biopsies reveal information of additional clinical significance. CONCLUSIONS: Although in some cases MRI may provide additional information, conventional perinatal autopsy remains the gold standard for the investigation of fetal death. The utility of adding percutaneous organ biopsies, without imaging guidance, to an MRI-based fetal autopsy remains unproven. Postmortem MRI, combined with ancillary investigations such as placental histology, external examination by a pathologist, cytogenetics and plain radiography provided information of equivalent clinical significance in the majority of cases.

The toddler refusing to weight-bear: a revised imaging guide from a case series.

BACKGROUND: The previously mobile child who refuses to walk or weight-bear is a common presentation to the accident and emergency department, for which there are a number of causes. One uncommon cause is discitis, an inflammatory process of the intervertebral disc, which is easily diagnosed with spinal magnetic resonance imaging (MRI). A case series of three patients is presented of non-weight-bearing children in whom there was a delay in making the diagnosis of lumbosacral discitis. None presented with back pain, spinal symptoms or abnormal neurological findings, and a full range of movement of both hips was found. METHODS: All patients underwent conventional radiography and ultrasound, but diagnoses were made on spinal MRI, with two patients undergoing bone scintigraphy before this. RESULTS: The mean delay was 15.6 days (range 13-20) from presentation at the hospital to MRI. All three patients made a good clinical recovery with intravenous antibiotics. CONCLUSION: These cases are presented in order to heighten the awareness of this disease entity and its imaging findings, and suggest new guidelines for the appropriate radiological investigations in this clinical setting.

Evaluation of image quality and radiation dose in adolescent thoracic imaging: 64-slice is preferable to 16-slice multislice CT.

There is a constant drive for radiology departments to acquire newer and improved CT machines in order to facilitate faster procedures and a greater repertoire of examinations. However, it is unclear whether the newer technology provides significantly improved image quality, or carries radiation dose implications for patients during everyday clinical practice. We assessed image quality and radiation dose in 15 children and young adults aged 9.3-19.5 years who underwent thoracic imaging on both 16-slice (16CT) and 64-slice (64CT) CT machines. Images were assessed for image quality on a visual analogue scale (1 = unacceptable; 5 = perfect) and preferred image set. All datasets were diagnostically acceptable (scores of 3 or more). The scores for 64CT datasets were significantly better than for 16CT datasets (mean scores of 4.5 and 4.0, respectively; p<0.05). The mean dose-length product (DLP) given was significantly higher during 16CT examinations at 152 mGy cm (effective dose, 2.1 mSv) than for 64CT examinations at 136 mGy cm (1.9 mSv; p<0.05). On average, 64CT examination DLPs were 16 mGy cm (or 9%) lower than the equivalent 16CT examination DLPs. In the context of childhood and adolescent thoracic CT imaging, and using the same software from the same manufacturers, 64CT examinations provide better image quality and give a lower effective dose than do 16CT examinations. If the choice were available, it would be pertinent to use 64CT for this patient group.

Feasibility of percutaneous organ biopsy as part of a minimally invasive perinatal autopsy.

To determine the feasibility of percutaneous fetal organ biopsies in the context of a 'minimally invasive' perinatal autopsy after stillbirth and termination for abnormality is the aim of this study. We assessed successful biopsy rate and the proportion adequate for histological examination in 30 fetuses undergoing organ sampling before autopsy. The relationship between gestational age, body weight, death-biopsy interval, operator experience and successful biopsy rate was investigated. Significant findings from conventional block histology were compared with corresponding percutaneous biopsies. Of 210 organ biopsies attempted from seven target organs, 107 were obtained, of which 94 were adequate for pathological comment. The median delivery-autopsy interval was 4 (range 2-11) days. Adequate samples were obtained from the lung in 86% cases (95% CI 68, 96%), liver 76% (95% CI 56, 90%) and less frequently for the myocardium, kidney, adrenal, thymus and spleen. There was no relationship between biopsy success and time to biopsy, gestational age, body weight and user experience. No histological abnormalities found at autopsy were diagnosed from needle biopsies. Although targeted percutaneous biopsies appear feasible for some organs, fewer than 50% of all biopsies are adequate for histological examination. This technique cannot be considered to provide useful clinical information as part of a 'minimally invasive' perinatal autopsy.

Use of a confidence scale in reporting postmortem fetal magnetic resonance imaging.

OBJECTIVES: Postmortem magnetic resonance imaging (MRI) may be an alternative to conventional autopsy. However, it is unclear how confident radiologists are in reporting such studies. We sought to determine the confidence with which radiologists report on various fetal organs by developing a scale to express their confidence of normality and abnormality, and to place this in the context of a pathological diagnosis of whether the organ was in fact normal or abnormal. METHODS: Thirty fetuses, aged 16-39 gestational weeks and weighing 61-3270 g, underwent postmortem MRI prior to conventional autopsy. MRI studies were reported by two radiologists with access to the clinical and sonographic history: a neuroradiologist, reporting head and neck, and a pediatric radiologist, reporting thorax, abdomen and pelvis. Radiologists used a scale (0 = definitely abnormal, 100 = definitely normal, 50 = unable to comment) to indicate their confidence of anatomical structures being normal or abnormal, using a checklist. Conventional autopsies were performed by pediatric pathologists blinded to the MRI findings, and these were considered the reference standard. RESULTS: Most normal fetal organs had high scores on postmortem MRI, with median confidence scores above 80. However, the atrioventricular valves, duodenum, bowel rotation and pancreas proved more difficult to assess, with median scores of 50, 60, 60 and 62.5, respectively. Abnormal cardiac atria and ventricles, kidneys, cerebral hemispheres and corpus callosum were always detected with high or moderate degrees of confidence (median scores of 2.5, 5, 0, 0 and 30 respectively). However, in two cases with abnormal cardiac outflow tracts, both cases scored 50. Kappa values, assessing agreement between MRI diagnoses of abnormality and autopsy, were high for the brain (0.83), moderate for the lungs (0.56) and fair for the heart (0.33). CONCLUSIONS: This scoring system represents an attempt to define the confidence of radiologists to report varying degrees of normality and abnormality following z ex-utero fetal MRI. While most fetal anatomy is clearly visualized on postmortem MRI, radiologists may lack confidence reporting such studies and there are particular problems with assessment of some cardiac and gastrointestinal structures, both normal and abnormal.