Comparison of preterm and term equivalent age MRI for the evaluation of preterm brain injury.

OBJECTIVE: To compare information obtained from preterm magnetic resonance imaging (MRI; 31-34 weeks) brain scan to that done at term equivalent age. STUDY DESIGN: Prospective observational study of premature infants with evidence or suspicion of parenchymal brain injury on cranial ultrasound. Brain injury on two scans scored using a scoring system and analyzed. RESULTS: Fourteen infants with a median (range) gestation at birth of 28 (25-29) weeks and birth weight of 1254 (680-1557) grams were studied. There was a strong correlation between the brain injury scores for the two scans (Spearman ρ=0.87, P=0.001) with excellent agreement between two radiologists (interclass correlation coefficient 0.9-0.94). There was also a high level of agreement between the preterm and term MRI two scores (Intraclass correlation coefficient, 0.79 (0.53-0.94)). CONCLUSIONS: Preterm MRI is a feasible option for the assessment of preterm brain injury and analysis of data obtained from scan at preterm age is comparable to that obtained at term equivalent age.

Paediatric CT dose: a multicentre audit of subspecialty practice in Australia and New Zealand.

OBJECTIVES: To evaluate paediatric CT dosimetry in Australia and New Zealand and calculate size-specific dose estimates (SSDEs) for chest and abdominal examinations. METHODS: Eight hospitals provided data from 12 CT systems for 1462 CTs in children aged 0-15. Imaging data were recorded for eight examinations: head (trauma, shunt), temporal bone, paranasal sinuses, chest (mass) and chest HRCT (high-resolution CT), and abdomen/pelvis (mass/inflammation). Dose data for cranial examinations were categorised by age and SSDEs by lateral dimension. Diagnostic reference ranges (DRRs) were defined by the 25th and 75th percentiles. Centralised image quality assessment was not undertaken. RESULTS: DRRs for 201 abdominopelvic SSDEs were: 2.8-4.7, 3.6-11.5, 8.5-15.0, 7.6-15, and 10.6-16.2 for the <15 cm, 15-19 cm, 20-24 cm, 25-29 cm and >30 cm groups, respectively. For 147 chest examinations using these body width categories, SSDE DRRs were 2.0-4.4, 3.3-7.9, 4.0-9.4, 4.5-12, and 6.5-12. Kilovoltage peak (kVp), but not AEC or IR, was associated with SSDE (parameter estimate [standard error]: 0.12 (0.03); p < 0.0001). CONCLUSIONS: Australian and New Zealand paediatric CT DRRs and abdominal SSDEs are comparable to international data. SSDEs for chest examinations are proposed. Dose variations could be reduced by adjusting kVp. KEY POINTS: • SSDEs can be calculated for all patients, CT systems, and practices • Kilovoltage peak (kVp) has the greatest association with dose in similar-sized patients • Paediatric DRRs for CT are now available for use internationally.

Diffusion tensor imaging of acute inflammatory lesion evolution in multiple sclerosis.

The initiating events in multiple sclerosis (MS) plaque formation are poorly understood. Retrospective analysis of serial imaging data can improve the understanding of tissue changes characterising acute MS lesion evolution. This study aimed to assess lesion evolution using diffusion tensor imaging data from serially acquired scans from 22 patients with MS. Mean diffusivity (MD) and fractional anisotropy (FA) were measured from 13 suitable plaques from five patients and carefully matched regions of contralateral normal-appearing white matter. Measurement times were on average: 5 months and 1 month prior to, during, and 1 month and 2 months post gadolinium-enhancement. A significant increase in MD (7.25%) but no change in FA was observed in white matter areas that exhibited enhancement 5 months later. The pre-lesional MD increase was significantly correlated with the MD increase 2 months subsequent to enhancement (R=0.73, p=0.04) but not to the MD increase during enhancement (R=0.11). These results suggest that MD is sensitive to tissue changes that precede blood-brain barrier (BBB) breakdown by at least 5 months and that MD assessments may predict injury following BBB restoration.

Ossification variants of the femoral condyles are not associated with osteochondritis dissecans.

PURPOSE: To determine if ossification variants of the femoral condyles involving the subchondral bone plate are associated with osteochondritis dissecans (OCD). MATERIALS AND METHODS: The prevalence of ossification variants of the unaffected femoral condyle in 116 patients (aged 9-14 years) with unicondylar OCD on MRI (magnetic resonance imaging) of the knee was compared to a control group of 579 patients (aged 9-14 years) without OCD. The evolution of the ossification variants in both groups was studied by reviewing follow-up MR imaging side by side with the baseline study. RESULTS: The prevalence of ossification variants in the unaffected condyle in patients with OCD (12.9%) and in the control group of patients without OCD (12.6%) was similar (p=0.88). Evolution of ossification variants to OCD was not seen on follow-up MRI examinations. All variants had decreased in size or were no longer visible. CONCLUSION: Ossification variants of the femoral condyle that involve the subchondral bone plate are not associated with OCD. CLINICAL RELEVANCE STATEMENT: Ossification variants are not associated with OCD, indicating that routine MRI follow-up in affected children is not mandatory.

More harm than good? The anatomy of misguided shielding of the ovaries.

OBJECTIVE: Popular gonad shield designs aim to provide coverage of the true pelvis, which is presumed to be the probable location of the ovaries. Shields are frequently placed inaccurately, especially in children, obscuring important orthopaedic landmarks on pelvic radiographs. We aimed to identify the position of the ovaries and asses how this may vary with age and the degree of bladder filling. We aimed to identify the position of the ovaries and asses how this may vary with age and the degree of bladder filling. METHODS: Using MRI examinations of the pelvis in women and children, we located 594 ovaries in 306 female patients aged from birth to 59 years. RESULTS: This study provides new evidence that bladder filling affects ovary position. A lower than expected number of patients had both ovaries within the pelvis if the bladder contained more than a moderate volume of urine. Bladder emptying should be achieved wherever practical if a shield is used. In children under the age of 7 years, more than half (19/37) had at least one ovary outside the true pelvis. There was a significant association between age and ovary position, with the percentage of patients with one or both ovaries outside the true pelvis decreasing with age (χ(2), p<0.0001). CONCLUSION: The embryological descent of the ovaries into the pelvis would appear to continue after birth, well into childhood. Current popular shield designs are therefore inappropriate for use in young children. Given the high risk of obscuring critical landmarks, coupled with the new evidence that even accurate placement will not necessarily protect the ovaries, the use of pelvic shields in girls should be reconsidered.

MR imaging findings of lesions involving cartilage and bone in the paediatric knee: a pictorial review.

The knee is the joint which is most commonly imaged by MRI in children and adolescents. With increasing participation in competitive sports, traumatic knee injuries with osteochondral lesions are increasingly common in children. However, it is also important to exclude non traumatic conditions that result in defects of the articular cartilage and/or subchondral bone plate or growth plate of the knee, since timely diagnosis and therapy may help prevent lifelong disability in these patients. Moreover, there are normal variants that occur in the ossifying knee that should not be mistaken for lesions. The aim of this essay is to review the wide range of conditions that may result in MRI signal changes of the ossifying knee in children.

A randomized trial of high-dose vitamin D2 in relapsing-remitting multiple sclerosis.

OBJECTIVE: Higher latitude, lower ultraviolet exposure, and lower serum 25-hydroxyvitamin D (25OHD) correlate with higher multiple sclerosis (MS) prevalence, relapse rate, and mortality. We therefore evaluated the effects of high-dose vitamin D2 (D2) in MS. METHODS: Adults with clinically active relapsing-remitting MS (RRMS) were randomized to 6 months' double-blind placebo-controlled high-dose vitamin D2, 6,000 IU capsules, dose adjusted empirically aiming for a serum 25OHD 130-175 nM. All received daily low-dose (1,000 IU) D2 to prevent deficiency. Brain MRIs were performed at baseline, 4, 5, and 6 months. Primary endpoints were the cumulative number of new gadolinium-enhancing lesions and change in the total volume of T2 lesions. Secondary endpoints were Expanded Disability Status Scale (EDSS) score and relapses. RESULTS: Twenty-three people were randomized, of whom 19 were on established interferon or glatiramer acetate (Copaxone) treatment. Median 25OHD rose from 54 to 69 nM (low-dose D2) vs 59 to 120 nM (high-dose D2) (p = 0.002). No significant treatment differences were detected in the primary MRI endpoints. Exit EDSS, after adjustment for entry EDSS, was higher following high-dose D2 than following low-dose D2 (p = 0.05). There were 4 relapses with high-dose D2 vs none with low-dose D2 (p = 0.04). CONCLUSION: We did not find a therapeutic advantage in RRMS for high-dose D2 over low-dose D2 supplementation. CLASSIFICATION OF EVIDENCE: This study provides Class I evidence that high-dose vitamin D2 (targeting 25OHD 130-175 nM), compared to low-dose supplementation (1,000 IU/d), was not effective in reducing MRI lesions in patients with RRMS.

Hippocampus, amygdala and global brain changes 10 years after childhood traumatic brain injury.

Traumatic brain injury (TBI) in children results in damage to the developing brain, particularly in severely injured individuals. Little is known, however, of the long-term structural aspects of the brain following childhood TBI. This study investigated the integrity of the brain 10 years post-TBI using magnetic resonance imaging volumetrics in a sample of 49 participants with mild, moderate and severe TBI, evaluated against a normative sample of 20 individuals from a pediatric database with comparable age and gender distribution. Structural integrity was investigated in gray and white matter, and by manually segmenting two regions of interest (hippocampus, amygdala), potentially vulnerable to the effects of childhood TBI. The results indicate that more severe injuries caused a reduction in gray and white brain matter, while all TBI severity levels resulted in increased volumes of cerebrospinal fluid and smaller hippocampal volumes. In addition, enlarged amygdala volumes were detected in severely injured patients compared to their mild and moderate counterparts, suggesting that childhood TBI may disrupt the development of certain brain regions through diffuse pathological changes. The findings highlight the lasting impact of childhood TBI on the brain and the importance of monitoring brain structure in the long-term after early injury.

MR imaging findings of haemophilic arthropathy of the elbow in children.

Haemophilic arthropathy of the elbow is a rare cause of elbow pain in children and adolescents. The purpose of this study is to determine the MR appearance of the spectrum of lesions found in haemophilic arthropathy of the elbow at initial MR imaging. It is important to be aware of the early changes in this entity, since early diagnosis and treatment of the disease may prevent progressive joint destruction.

Value and limitations of diffusion-weighted imaging in grading and diagnosis of pediatric posterior fossa tumors.

DWI reportedly accurately differentiates pediatric posterior fossa tumors, but anecdotal experience suggests limitations. In 3 years, medulloblastoma and JPA were differentiated by DWI alone in 23/26 cases (88%). Ependymoma (n = 5) could not be reliably differentiated from medulloblastoma or JPA. A trend toward increased diffusion restriction in higher grade tumors (1/14 grade I, 7%; 9/12 grade IV, 75%) had too much overlap to predict the grade of individual cases. The overlap in ADC between tumor types appeared partly due to technical factors (in small, heterogeneous, calcific, or hemorrhagic tumors) but also likely reflected true histologic variability, given that our 3 overlap cases included a desmoplastic medulloblastoma, an anaplastic ependymoma, and a JPA with restricted diffusion in its nodule. Simple structural features (macrocystic tumor, location off midline) aided in distinguishing JPA from the other tumors in these cases.

MRI demonstrates the extension of juxta-articular venous malformation of the knee and correlates with joint changes.

OBJECTIVE: Juxta-articular venous malformations (VMs) are uncommon, but may cause early arthropathy of the knee in children and adolescents. We sought to describe the prevalence, extent and initial magnetic resonance imaging (MRI) features of knee arthropathy in children with VM adjacent to the knee joint. METHODS: Thirty-five patients with VM adjacent to the knee who had MRI performed between 2000 and 2009 were identified through a keyword search of the radiology information system. RESULTS: VM extended to the joint in 17 of the 35 patients (5.4-21.5 years, mean 11.8 years). Most of these 17 patients had joint changes (15/17, 88%), most commonly haemosiderin deposition (14/17, 82%). Other findings included the presence of subchondral bone lesions (eight, 47%), cartilage loss (six, 35%), synovial thickening (six, 35%), marrow oedema (six, 35%), joint effusion (five, 29%), subchondral cysts (five, 29%) and one loose body (6%). VM location and size did not correlate with the degree of articular involvement. Joint changes were present in focal as well as non-discrete VM. CONCLUSION: We found that the frequency of arthropathy increased with extension of VM into the joint itself. This finding stresses the importance of early MRI evaluation of all juxta-articular VM.

Imaging for Crohn disease: use of 3-T MRI in a paediatric setting.

This study was carried out to review our experience with 3-T MRI in the assessment of Crohn disease in a paediatric population. Twenty-four patients with biopsy proven Crohn disease identified on the radiology information system underwent abdominal MRI, with or without pelvic MRI. Twenty-eight studies were carried out on a 3-T scanner at a tertiary paediatric hospital. Eight of 24 of these (30%) had a gastrointestinal barium study, 2 of 24 (8%) a CT and 9 of 24 (38%) an abdominal ultrasound. The different MRI sequences were rated for observation of the bowel wall and abnormalities (0-5). The findings were correlated to relevant findings on endoscopy, examination under anaesthesia (EUA) and where available surgery, barium studies, CT and ultrasound. In this study, the colon was involved in 5 of 28 (18%), small bowel in 7 of 28 (25%), terminal ileum in 5 of 28 (18%). All the perineal studies (9 of 9) showed abnormalities. Sinus tracts or fistulas were identified in 7 of 28 (25%) studies. The mean rating of the different MRI sequences in showing bowel wall and changes of Crohn disease was T2 TSE 3.6, T2 half fourier aquisition single shot turbo spin echo (HASTE) with a long TE 3.6, T2 HASTE with short TE 3.4, true fast imaging with steady state precession (FISP) 2.7, T1 4.1 and Post-contrast T1 4.3. The T2 HASTE sequences with thinner slices improved observation. Detection of superficial abnormalities was similar on the 3D VIBE images and on the post-contrast T1 spin-echo (SE) sequences. In five of nine (56%) of those that had ultrasound, both studies were abnormal, with incomplete correlation of the abnormalities. Computed tomography and MRI were abnormal in two of two (100%) patients with good correlation of the abnormalities in one; in the other there was a minimal discrepancy in the estimation of the length of involved bowel. In 7 of 11 (64%) the barium study was abnormal. Good correlation to MRI findings was found in five of seven (71%) of patients. In two of seven (29%) both studies were abnormal, with incomplete correlation of the abnormalities. Barium underestimated the length of involved segment in these patients with inflammatory ileal thickening and ulceration. Notably, in both studies compression was limited because of patient discomfort and the involved segments obscured by overlap. Abdominal and pelvic MRI at 3 T is a useful imaging technique for evaluation of Crohn disease in the children. The extent of bowel wall involvement and extra-intestinal complications, such as abscesses and fistulas can be accurately assessed non-invasively, without the use of ionizing radiation or sedation.

Practice MRI: reducing the need for sedation and general anaesthesia in children undergoing MRI.

The aim of this study was to evaluate the effectiveness of a practice magnetic resonance unit, in preparing children to undergo magnetic resonance procedures without general anaesthesia (GA) or sedation. The records of children who attended the practice MRI between February 2002 and April 2004 were retrospectively reviewed. Each record was assessed as to whether the child had passed or failed the practice MRI intervention. Those children who were considered to have passed and were proceeded to a clinical non-GA MRI had the report of the clinical scan reviewed. If the scan had been reported as non-diagnostic because of movement artefact it was classified as a failed scan, otherwise it was considered a pass. One hundred and thirty-four children undertook a practice MRI (age range 4.1-16.1 years, median age 7.7 years, 47% boys) and 120/134 (90%) passed the practice session. In all, 117/120 (98%) subsequently had a clinical non-GA MRI and 110/117 (94%) passed (median age 7.8 years, 47% boys). Preparation is a safe and effective method to reduce the need for sedation and GA in children undergoing a clinical MRI scan. It provides a positive medical experience for children, parents and staff, and results in cost savings for the hospital.

Complementary use of radiological skeletal survey and bone scintigraphy in detection of bony injuries in suspected child abuse.

AIM: To compare the effectiveness of radiological skeletal survey and bone scintigraphy for the detection of bony injuries in cases of suspected child abuse. METHODS: All cases with a discharge diagnosis of child abuse that presented to the Royal Children's Hospital between 1989 and 1998 were retrieved, and those children that had undergone both skeletal survey and bone scintigraphy (radioisotope bone scan) within a 48 hour period were included in this study. Both examinations followed rigid departmental protocols and protocols remained identical throughout the timeframe of the study. The reports of the skeletal surveys and bone scans were retrospectively reviewed by a paediatric radiology fellow and consultant paediatric radiologist. RESULTS: The total number of bony injuries identified was 124 in 30 children. Of these, 64 were identified on bone scan and 77 on skeletal survey. Rib fractures represented 60/124 (48%) of the bony injuries and were present in 16/30 children (53%), of which 62.5% had multiple rib fractures. Excluding rib fractures, there were 64 (52%) bony injuries, of which 33% were seen on both imaging modalities, 44% were seen on skeletal survey only, and 25% were seen on bone scans alone. Metaphyseal lesions typical of child abuse were present in 20 cases (31%) on skeletal survey; only 35% of these were identified on bone scan. Six children (20%) had normal skeletal surveys, with abnormalities shown on bone scan. There were three children (10%) with normal bone scans who were shown to have injuries radiographically. CONCLUSIONS: Skeletal survey and bone scintigraphy are complementary studies in the evaluation of non-accidental injury, and should both be performed in cases of suspected child abuse.

Endovascular management of vein of Galen aneurysmal malformations presenting in the neonatal period.

BACKGROUND AND PURPOSE: Neonates with vein of Galen aneurysmal malformations (VGAMs) presenting with cardiac failure have high morbidity and mortality, and outcomes are significantly better in those presenting in later childhood. Neurologic outcomes in survivors are perceived to be uniformly poor, which may lead to the neonate being denied treatment. We assessed outcomes of modern neonatal intensive care and endovascular embolization in a consecutive series of such neonates presenting with cardiac failure. METHODS: Between 1996 and 1998, five infants (three male, two female) were diagnosed with symptomatic VGAMs in the first week of life, four of whom had intractable, high-output cardiac failure and underwent initial endovascular treatment. There were 15 endovascular procedures and one neurosurgical clipping in these five patients. Transarterial and transvenous routes were required, using multiple embolic agents. We emphasized the use of sonographically guided, percutaneous transtorcular-venous-access, moveable-core guidewire as an embolic agent; routine MR imaging; and MR angiography. RESULTS: Immediate outcomes included control of cardiac failure with normal neurologic function in four (80%) patients and one (20%) death from intractable cardiac failure. On follow-up examination, three (60%) infants showed no evidence of neurologic abnormality or cardiac failure; one (20%) infant showed moderate developmental delay. Two have had no further shunting on angiography, one has minimal flow, and one is awaiting follow-up imaging. CONCLUSION: Endovascular therapy with modern neuroanesthetic and neurointensive care can provide good outcomes even in the highest-risk neonates with VGAMs and cardiac failure. If medical management of cardiac failure fails, and there is no evidence of gross cerebral parenchymal damage on imaging, urgent endovascular treatment is feasible and can reduce the almost-100% mortality otherwise expected, without invariably severe morbidity. Use of multiple embolization strategies in multiple stages usually is necessary in these patients, and novel approaches and embolic agents may be necessary.

A randomized trial of very early decompressive craniectomy in children with traumatic brain injury and sustained intracranial hypertension.

OBJECT: The object of our study was to determine, in children with traumatic brain injury and sustained intracranial hypertension, whether very early decompressive craniectomy improves control of intracranial hypertension and longterm function and quality of life. METHODS: All children were managed from admission onward according to a standardized protocol for head injury management. Children with raised intracranial pressure (ICP) were randomized to standardized management alone or standardized management plus cerebral decompression. A decompressive bitemporal craniectomy was performed at a median of 19.2 h (range 7.3-29.3 h) from the time of injury. ICP was recorded hourly via an intraventricular catheter. Compared with the ICP before randomization, the mean ICP was 3.69 mmHg lower in the 48 h after randomization in the control group, and 8.98 mmHg lower in the 48 hours after craniectomy in the decompression group (P=0.057). Outcome was assessed 6 months after injury using a modification of the Glasgow Outcome Score (GOS) and the Health State Utility Index (Mark 1). Two (14%) of the 14 children in the control group were normal or had a mild disability after 6 months, compared with 7 (54%) of the 13 children in the decompression group. Our conclusion was that when children with traumatic brain injury and sustained intracranial hypertension are treated with a combination of very early decompressive craniectomy and conventional medical management, it is more likely that ICP will be reduced, fewer episodes of intracranial hypertension will occur, and functional outcome and quality of life may be better than in children treated with medical management alone (P=0.046; owing to multiple significance testing P <0.0221 is required for statistical significance). This pilot study suggests that very early decompressive craniectomy may be indicated in the treatment of traumatic brain injury.

Magnetic resonance imaging findings in cerebral palsy.

OBJECTIVE: To review all cases of cerebral palsy (CP) that had magnetic resonance imaging (MRI) over a defined period of time. METHODOLOGY: The MRI brain scans of 42 children (12 premature, 30 full-term) with CP were studied. The scans were performed at the Royal Children's Hospital, Melbourne, between January 1995 and June 1996. RESULTS: Abnormalities were found in 39 of the 42 scans. Five children had cortical malformations and three children had white matter hypoplasia, indicating insults during the second trimester of pregnancy. Twenty-one children had hypoxic-ischaemic lesions (eight premature, 13 full-term) with patterns of periventricular leucomalacia, subcortical lesions or cortical infarction indicating insults perinatally or in the third trimester. Only 10 children had scans that could not be categorized into these groups. CONCLUSIONS: In this study sample of children with CP, MRI was useful in revealing underlying brain abnormalities, most of which were due to events in the third trimester or the perinatal period.

Tracheobronchial malacia and stenosis in children in intensive care: bronchograms help to predict oucome.

BACKGROUND: Severe tracheobronchial malacia and stenosis are important causes of morbidity and mortality in children in intensive care, but little is known about how best to diagnose these conditions or determine their prognosis. METHODS: The records of all 62 children in whom one or both of these conditions had been diagnosed by contrast cinetracheobronchography in our intensive care unit in the period 1986-95 were studied. RESULTS: Seventy four per cent of the 62 children had congenital heart disease; none was a preterm baby with airways disease associated with prolonged ventilation. Fifteen of the children had airway stenosis without malacia; three died because of the stenosis and two died from other causes. Twenty eight of the 47 children with malacia died; only eight children survived without developmental or respiratory handicap. All children needing ventilation for malacia for longer than 14 consecutive days died if their bronchogram showed moderate or severe malacia of either main bronchus (15 cases), or malacia of any severity of both bronchi (three additional cases); all children needing ventilation for malacia for longer than 21 consecutive days died if their bronchogram showed malacia of any severity of the trachea or a main bronchus (three additional cases). These findings were strongly associated with a fatal outcome (p<0.00005); they were present in 21 children (all of whom died) and absent in 26 (of whom seven died, six from non-respiratory causes). They had a positive predictive value for death of 100%, but the lower limit of the 95% confidence interval was 83.9% so up to 16% of patients meeting the criteria might survive. CONCLUSION: In this series the findings on contrast cinetracheobronchography combined with the duration of ventilation provided a useful guide to the prognosis of children with tracheobronchomalacia. The information provided by bronchoscopy was less useful.

The DMSA scan in paediatric urinary tract infection.

The objective of the present paper was to review the use of the dimercaptosuccinic acid (DMSA) scan in urinary tract infection at British Columbia's Children's Hospital to determine the frequency of cortical defects and the association between vesico-ureteric reflux and the presence of cortical defects in children with urinary tract infection. A total of 129 consecutive children with a urinary tract infection referred for a DMSA scan in a 2-year period (January 1992-January 1994) were retrospectively studied. The results were analysed in terms of kidneys, and the incidence of cortical defects was determined. Eighty-eight patients (68%) had a radiographic micturating cysto-urethrogram within 6 months of the DMSA scan, and in this group the relationship of defects with vesico-ureteric reflux was determined. Overall, 81/258 (31%) of kidneys had a cortical defect on a DMSA scan. Of those who had a micturating cysto-urethrogram, 53/176 (30%) kidneys had vesico-ureteric reflux, and of those that had reflux, 21/53 (40%) had a cortical defect on a DMSA scan. In the group of children without reflux, 38/123 (31%) had a cortical defect. Renal cortical scan defects are common findings in paediatric urinary infection, and frequently occur in the absence of vesico-ureteric reflux. These defects represent either established scars or acute pyelonephritis that can proceed to scarring. The micturating cysto-urethrogram alone is insufficient as a screening modality to identify those kidneys at risk of renal scarring.