[Show abstract][Hide abstract] ABSTRACT: Background:
Birth-related acute profound hypoxic-ischaemic brain injury has specific patterns of damage including the paracentral lobules.
To test the hypothesis that there is anatomically coherent regional volume loss of the corpus callosum as a result of this hemispheric abnormality.
Materials and methods:
Study subjects included 13 children with proven acute profound hypoxic-ischaemic brain injury and 13 children with developmental delay but no brain abnormalities. A computerised system divided the corpus callosum into 100 segments, measuring each width. Principal component analysis grouped the widths into contiguous anatomical regions. We conducted analysis of variance of corpus callosum widths as well as support vector machine stratification into patient groups.
There was statistically significant narrowing of the mid-posterior body and genu of the corpus callosum in children with hypoxic-ischaemic brain injury. Support vector machine analysis yielded over 95% accuracy in patient group stratification using the corpus callosum centile widths.
Focal volume loss is seen in the corpus callosum of children with hypoxic-ischaemic brain injury secondary to loss of commissural fibres arising in the paracentral lobules. Support vector machine stratification into the hypoxic-ischaemic brain injury group or the control group on the basis of corpus callosum width is highly accurate and points towards rapid clinical translation of this technique as a potential biomarker of hypoxic-ischaemic brain injury.
[Show abstract][Hide abstract] ABSTRACT: This report discusses the syndrome of amnionic bands, anencephaly, schizencephaly and hydranencephaly, four entities whose pathogenesis includes significant injury to the fetus in utero.
[Show abstract][Hide abstract] ABSTRACT: Objective
The aim of this study was to quantify the risk of brain abnormalities in single twin demise of monochorionic pregnancies and to describe the type of brain injuries. using ultrasound and in utero MR imaging (iuMR).Methods
Monochorionic twin pregnancies complicated by demise of one twin referred between 2004-2013 were reviewed. Ultrasound was performed in a tertiary centre prior to iuMR The cases were subdivided into those associated with co-twin loss following fetoscopic laser ablative treatment for twin/twin transfusion syndrome (TTTS) and those associated with spontaneous fetal demiseResultsSixty-eight cases were identified, 27/68 following treatment for TTTS and 41/68 with spontaneous fetal demise. Nine (13.2%) had brain abnormalities on iuMR and the rate of brain abnormalities was similar in the two groups. Expert ultrasound and iuMR findings agreed in 3/9 of those cases and in 6/9 cases ultrasound underestimated or missed the pathology.Conclusion
Monochorionic twin pregnancies with single fetal demise are complex pregnancies with increased risk of acquired brain pathology, although the rate of brain abnormalities in our study is lower than other publications. iuMR in such complicated pregnancies is a useful adjuvant imaging technique which appears to detect brain pathologies better than prenatal ultrasonography. This article is protected by copyright. All rights reserved.
[Show abstract][Hide abstract] ABSTRACT: Introduction and objectives Magnetic resonance (MR) imaging of the hyperpolarised noble gases 3He and 129Xe provides exquisite depiction of pulmonary ventilation. In addition, MR measurement of the apparent diffusion coefficient (ADC) of 3He gas has proven clinical utility in assessment of emphysema. Furthermore, xenon is soluble and is a promising marker of pulmonary gas-exchange. The motivation of this work was to demonstrate non-invasive quantification of whole-lung septal thickness (ST) and helium ADC in subjects with idiopathic pulmonary fibrosis (IPF) and systemic sclerosis (SSc) using 129Xe and 3He MR.
Methods Hyperpolarised 129Xe spectroscopy was performed on ten healthy volunteers (23–74 yrs), four subjects with SSc and four with IPF at 1.5 T. A chemical shift saturation recovery (CSSR) method was used to assess the dynamics of xenon uptake into parenchymal tissues and blood and to derive quantitative information about lung microstructure. From the subject cohort, six volunteers and seven patients were also scanned at 1.5 T with a diffusion-weighted sequence to determine 3He ADC values. For comparison with MR experiments, standard pulmonary function tests including the diffusing capacity of carbon monoxide (DLCO) were performed.
Results Pulmonary function was significantly worse in both SSc and IPF subjects than healthy volunteers (DLCO < 45% in IPF patients). Both 129Xe CSSR ST and 3He ADC values were elevated in subjects with SSc, and to a larger degree in those with IPF, compared with healthy volunteers (Figure 1, top). These two MR metrics correlated significantly, suggesting that fibrotic remodelling of tissue both degrades gas-exchange efficiency and induces alveolar widening causing less-restricted gas diffusion (although emphysema was reported for only one subject on CT). The 129Xe CSSR-derived ST values correlated well with whole-lung DLCO (Figure 1, bottom) and in healthy volunteers, ST increased with age (p < 0.05).
Conclusions Hyperpolarised 129Xe and 3He MR techniques are sensitive to small changes in gas-exchange efficiency and alveolar surface geometry, respectively. These two factors appear to have an intrinsic link, identified in the presence of fibrotic lung disease without obvious emphysema. Further application of these MR techniques may prove useful in the diagnosis/assessment of different forms of ILD.
[Show abstract][Hide abstract] ABSTRACT: Paediatric diffuse intrinsic pontine glioma (DIPG) is noteworthy for its fibrillary infiltration through neuroparenchyma and its resultant irregular shape. Conventional volumetry methods aim to approximate such irregular tumours to a regular ellipse, which could be less accurate when assessing treatment response on surveillance MRI. Region-of-interest (ROI) volumetry methods, using manually traced tumour profiles on contiguous imaging slices and subsequent computer-aided calculations, may prove more reliable.
[Show abstract][Hide abstract] ABSTRACT: To assess the sensitivity of the hyperpolarized 129Xe chemical shift saturation recovery (CSSR) technique for noninvasive quantification of changes to lung microstructure and function in idiopathic pulmonary fibrosis (IPF) and systemic sclerosis (SSc). Ten healthy volunteers, four subjects with SSc and four with IPF were scanned at 1.5 T. A CSSR pulse sequence was implemented using binomial-composite radiofrequency pulses to monitor 129Xe magnetization in tissues and blood plasma (T/P) and red blood cells (RBCs). The dynamics of 129Xe uptake into these compartments were fitted with three existing analytical models of gas diffusion to extract parameters of lung physiology. These parameters were quantitatively compared between models. Uptake of xenon into the pulmonary capillaries was impaired in subjects with IPF and SSc. Statistically significant septal thickening was measured by 129Xe CSSR in IPF patients. Preliminary data suggests age-dependent alterations to septal thickness in healthy volunteers. These findings were reproduced using each of the literature models. CSSR-derived parameters were compared with gold-standard indicators of pulmonary function; diffusing capacity of carbon monoxide and pulmonary transit-time. CSSR with hyperpolarized 129Xe is sensitive to pathology-induced degradation of lung structure/function and shows promise for quantification of disease severity and monitoring treatment response. Magn Reson Med 74:196–207, 2015.
Magnetic Resonance in Medicine 08/2014; DOI:10.1002/mrm.25400 · 3.57 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: MRI of the foetal brain in utero is performed in routine clinical practice using sequences that produce two-dimensional (2D) images. Recent developments in image post-processing have allowed the construction of three-dimensional (3D) volume data sets from 2D images acquired in different anatomical planes, but these have limitations due to the unpredictable nature of foetal movement. These limitations have been overcome by development of several different advanced computer techniques, which require specialist knowledge, software, and processing methods, which are rarely available in routine clinical settings. Our aim was to develop a technique that can be used in routine clinical situations without the need for custom-developed or expensive software by utilizing MRI sequences that can produce a 3D data set in "ultrafast" timescales. The 3D dataset, combined with versatile image post-processing and visualization techniques, has resulted in the production of high-resolution images of foetal brain surfaces in utero. The aim of this paper is to demonstrate our methods and early results by way of a pictorial review illustrating a range of developmental brain disease in utero.
[Show abstract][Hide abstract] ABSTRACT: Aim:
To study the associations between magnetic resonance proton spectroscopy (MRS) data and apparent diffusion coefficients (ADC) from the preterm brain with developmental outcome at 18 months corrected age and clinical variables.
Materials and methods:
A prospective observational cohort study of 67 infants born before 35 weeks gestational age who received both magnetic resonance imaging of the brain between 37 and 44 weeks corrected gestational age and developmental assessment around 18 months corrected age.
No relationships were found between ADC values and MRS results or outcome. MRS ratios involving N-acetyl aspartate (NAA) from the posterior white matter were associated with "severe" and "moderate to severe" difficulties, and fine motor scores were significantly lower in participants with a visible lactate doublet in the posterior white matter. The presence of a patent ductus arteriosus (PDA) was the only clinical factor related to NAA ratios.
Altered NAA levels in the posterior white matter may reflect subtle white matter injury associated with neuro-developmental difficulties, which may be related to a PDA. Further work is needed to assess the longer-term neuro-developmental implications of these findings, and to study the effect of PDAs on developmental outcome in later childhood/adolescence.
[Show abstract][Hide abstract] ABSTRACT: To review our experience of diagnosing hemimegalencephaly (HME) using in utero magnetic resonance imaging (MRI).
The MRI database in the Academic Unit of Radiology, University of Sheffield was searched using "hemimegalencephaly" and "in utero MR" as search terms. The antenatal histories and reports of ultrasound imaging were reviewed as well as the in utero MRI images.
Nine cases of foetal HME were located. One case was referred after ultrasound with the diagnosis of HME, one as a "complex brain malformation", and one as a "mass lesion". The other six were referred as "unilateral ventriculomegaly". A common finding in foetuses imaged in the second trimester was disruption of the normal "transient structures" found in the developing cerebral hemispheres.
HME is a difficult diagnosis to make using antenatal ultrasound and in utero MRI should be considered in cases of unilateral ventriculomegaly diagnosed at ultrasound. Disruption of the transient structures of the cerebral hemispheres is a common finding on in utero MRI and can sometimes produce mass-like appearances in the region of the germinal matrix/ganglionic eminence.
[Show abstract][Hide abstract] ABSTRACT: Dural venous sinus ectasia with thrombosis (DVSET) in the fetus is a rare condition that can be diagnosed prenatally with the use of fetal MR imaging, yet with limited indication of long-term clinical significance.
To describe and evaluate the diagnostic value of fetal MR imaging in the prenatal diagnosis of dural venous sinus ectasia with thrombosis and its clinical significance.
We report a series of nine fetuses with dural venous sinus ectasia with thrombosis. The mothers, located in four feto-maternal centres, were referred for fetal MR imaging due to space occupying lesions identified on second-trimester antenatal ultrasound.
In all but one case the dural venous sinus ectasia with thrombosis was in the vicinity of the venous confluence (VC) with various extension in the posterior dural sinuses. Antenatal follow-up imaging was performed in seven cases and showed progression in one, stable appearances in one and regression in five cases. Three pregnancies were terminated. In the remaining six cases there was no reported neurological deficit at up to 44 months of clinical follow-up.
This is among the largest series of postnatal clinical follow-up in cases of prenatal diagnosis of dural venous sinus ectasia with thrombosis in the literature. Clinical follow-up suggests a good prognosis when antenatal follow-up shows partial or complete thrombus resolution.
[Show abstract][Hide abstract] ABSTRACT: The mechanisms of cerebellar degeneration attributed to prolonged and excessive alcohol intake remain unclear. Additional or even alternative causes of cerebellar degeneration are often overlooked in suspected cases of alcohol-related ataxia. The objectives of this study were two fold: (1) to investigate the prevalence of gluten-related serological markers in patients with alcohol-related ataxia and; (2) to compare the pattern of brain involvement on magnetic resonance imaging between patients with alcohol and gluten ataxias.
Patients diagnosed with alcohol and gluten ataxias were identified from a retrospective review of patients attending a tertiary clinic. HLA genotype and serological markers of gluten-related disorders were recorded. Cerebellar volumetry, MR spectroscopy and voxel-based morphometric analyses were performed on patients and compared with matched control data.
Of 904 registered patients, 104 had alcohol ataxia and 159 had gluten ataxia. 61% of the alcohol ataxia group and 70% of the gluten ataxia group had HLA DQ2/DQ8 genotype compared to 30% in healthy local blood donors. 44% of patients with alcohol ataxia had antigliadin antibodies compared to 12% in the healthy local population and 10% in patients with genetically confirmed ataxias. None of the patients with alcohol ataxia and antigliadin antibodies had celiac disease compared to 40% in patients with gluten ataxia. The pattern of structural brain abnormality in patients with alcohol ataxia who had antigliadin antibodies differed from gluten ataxia and was identical to that of alcohol ataxia.
Alcohol related cerebellar degeneration may, in genetically susceptible individuals, induce sensitization to gluten. Such sensitization may result from a primary cerebellar insult, but a more systemic effect is also possible. The duration and amount of exposure to alcohol may not be the only factors responsible for the cerebellar insult.
PLoS ONE 10/2013; 8(10):e77638. DOI:10.1371/journal.pone.0077638 · 3.23 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Objective: To evaluate the capacity of a rapid T2 weighted three-dimensional (3D) sequence to diagnose foetal brain abnormalities by comparing the results with current two-dimensional (2D) methods. We have also made assessments of the estimates of energy deposition using those methods. Methods: 50 pregnant females were included in this study under the guidance of the institutional review board. All their foetuses had suspected brain abnormalities on antenatal ultrasonography or were at increased risk of a brain malformation based on the results of an earlier pregnancy. All the foetuses had a routine MR protocol that includes three orthogonal plane single-shot fast-spin echoes and 2D steady-state sequences. In addition, a 3D rapid steady-state sequence of the foetal brain was performed (acquisition time approximately 40 s), and the standard and 3D sequences were reported independently and the results were compared. The specific absorption rate (SAR) predicted by the scanner was recorded in 12 cases in order to estimate the energy deposited by the three sequences. Results: The 3D rapid steady-state sequences produced diagnostic-quality images in 41/50 (82%) cases. All the failures were in second trimester foetuses (9/26-35% failure rate). There was a discrepancy between the standard report and findings using the 3D sequence in 2/41 of the foetuses with good-quality 3D imaging. The predicted SAR deposition of the 3D steady-state sequences was comparable with the single-shot fast-spin echo sequence. Conclusion: Our initial assessments of a 3D rapid steady-state sequence to image the foetus are encouraging in terms of diagnostic information and acceptable energy deposition values. The high failure rate in second trimester foetuses probably relates to the greater mobility of the smaller foetuses, and improvements in the 3D sequence are required in terms of reduced acquisition time and higher resolution. Advances in knowledge: We have shown that 3D T2 weighted images of the foetal brain can be acquired in a clinical setting and produce diagnostic-quality imaging in a high proportion of cases. The success rate in acquiring diagnostic-quality images is related to gestational age. Good-quality images were obtained in all third trimester foetuses but only in approximately two-thirds of second trimester foetuses. This probably reflects the problem of the greater mobility of second trimester foetuses. 3D T2 weighted acquisitions have great potential for improving the antenatal diagnosis of foetal brain abnormalities and may reduce the time that a pregnant female needs to spend on the MR scanner.
The British journal of radiology 10/2013; 86(1030):20130168. DOI:10.1259/bjr.20130168 · 2.03 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Spinal neural tube defects are a heterogeneous group of disorders, which remain relatively common, with a prevalence of 1-2 per 1000 live births despite advances in maternal antenatal care. They range from mild disorders with limited neurodevelopmental sequelae to extensive abnormalities with significant morbidity and mortality. The advent of in utero magnetic resonance imaging has enabled accurate anatomical characterization of an increasing number of abnormalities with increasing confidence. Recognition of the salient radiological features of these disorders and their relationship to the embryogenesis of the spinal cord and its coverings is now possible. This review describes the radiological appearances of these disorders with examples from Fetal Imaging Unit, University of Sheffield to illustrate the key anatomical and radiological features to aid the radiologist in their recognition.
[Show abstract][Hide abstract] ABSTRACT: We have developed a Magnetic Resonance Imaging (MRI)-compatible system to enable gating of a scanner to the heartbeat of a foetus for cardiac, umbilical cord flow and other possible imaging applications. We performed radiofrequency safety testing prior to a fetal electrocardiogram (fECG) gated imaging study in pregnant volunteers (n = 3). A compact monitoring device with advanced software capable of reliably detecting both the maternal electrocardiogram (mECG) and fECG simultaneously was modified by the manufacturer (Monica Healthcare, Nottingham, UK) to provide an external TTL trigger signal from the detected fECG which could be used to trigger a standard 1.5 T MR (GE Healthcare, Milwaukee, WI, USA) gating system with suitable attenuation. The MR scanner was tested by triggering rapidly during image acquisition at a typical fetal heart rate (123 beats per minute) using a simulated fECG waveform fed into the gating system. Gated MR images were also acquired from volunteers who were attending for a repeat fetal Central Nervous System (CNS) examination using an additional rapid cardiac imaging sequence triggered from the measured fECG. No adverse safety effects were encountered. This is the first time fECG gating has been used with MRI and opens up a range of new possibilities to study a developing foetus.
[Show abstract][Hide abstract] ABSTRACT: Absent common carotid artery with independent origin of internal and external carotid arteries from the subclavian artery is a rare but recognized phenomenon. We describe one such case with an associated symptomatic proximal high-grade stenosis of the right internal carotid artery. The abnormal carotid anatomy was not initially well appreciated, resulting in a failed surgical exploration and subsequent successful endovascular carotid stenting. To our knowledge, this is the first reported case of carotid stent in a right internal carotid artery originating from the subclavian artery.
Journal of vascular surgery: official publication, the Society for Vascular Surgery [and] International Society for Cardiovascular Surgery, North American Chapter 06/2013; 59(5). DOI:10.1016/j.jvs.2012.11.138 · 3.02 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Objective:
To assess the natural history of isolated syringomyelia in children.
MRI reports from February 2007 to August 2011 mentioning syrinx were identified on Sheffield Children's PACS database. Scans with syringes having an AP diameter of > 1 mm and extending over at least two vertebral bodies were reviewed. Patients with an identifiable cause such as a Chiari malformation were then excluded.
Thirty-nine patients were included with a mean age at diagnosis of 10.6 years. The average syrinx AP diameter was 3.30 mm. The rostrocaudal length of the syringes varied between 2 and 19 vertebral bodies. Twenty-seven out of 39 syringes were thoracic in origin. There were 3 and 6 syringes involving the cervicothoracic and thoracolumbar regions, respectively, with 3 involving the cervical area only. Eleven out of 39 (Group I) patients were found "incidentally" during work-up for adolescent idiopathic scoliosis and these were considered as a separate group. These patients did not have any significant symptoms and were discharged following their scoliosis correction surgery. Syrinx was incidental in 14 further patients (Group II). Of the 14 patients, 11 remained asymptomatic with no change in syrinx morphology throughout follow up. Of the 14 patients, 3 were lost to follow-up. Of the 39 patients, 14 (Group III) presented with progressive back pain without any obvious clinical cause. Of the 14, 10 either improved or remained the same. Of the 14 patients, 3 underwent lumbar puncture, 1/14 having myelography. All 4/14 patients reported significant pain reduction on follow up following intervention.
Idiopathic syrinx is a benign pathology, which can be managed expectantly. Most cases remain stable or improve over time. In a small minority who have progressive back pain, we have found that lumbar puncture may be helpful in reducing symptoms.
British Journal of Neurosurgery 03/2013; 27(5). DOI:10.3109/02688697.2013.771728 · 0.96 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Purpose:
To re-engineer a standard clinical magnetic resonance (MR) imaging system to enable the acquisition, in the same breath hold, of lung images from two hyperpolarized gases (helium 3 [(3)He] and xenon 129 [(129)Xe]) with simultaneous registered anatomic proton (hydrogen 1 [(1)H]) MR images of lung structure.
Materials and methods:
Studies with (3)He and (129)Xe were performed with National Research Ethics Committee approval, with informed consent from the volunteer. (1)H-(3)He-(129)Xe MR imaging was achieved in the same breath by using mutually decoupled nested radiofrequency coil hardware capable of transmit and receive on each respective nucleus without power cross talk. MR pulse sequences were also developed for rapid switching between each nucleus. The system is demonstrated with triple-nuclear lung images in a healthy individual following inhalation of a mixture of (3)He and (129)Xe gases.
Spatially and temporally registered images of all three nuclei were obtained with high signal to noise ratio and high spatial resolution in the same breath.
The multinuclear technique is capable of providing registered lung images with mutually complementary functional and structural spatial information.