Xiao-Qi Ding

Normal brain maturation characterized with age-related T2 relaxation times: An attempt to develop a quantitative imaging measure for clinical use

Objectives:We studied age-related changes in T2 relaxation times from the normal maturating human brain under routine clinical MR examination conditions. Materials and Methods:In 70 healthy subjects aged between 3 weeks and 39 years, T2 maps of the brain in which the intensity of each pixel corresponded to T2 relaxation times were generated based on magnetic resonance imaging data collected with a triple spin echo sequence. T2 relaxation times in white matter (WM) and gray matter (GM) were measured in 6 distinctive regions of interest of the T2 maps. The age dependence of the T2 values was mathematically simulated using a biexponential function. Results:T2 values were largest at the age of 3 weeks (maximum: approximately 400 milliseconds for WM and 200 milliseconds for GM) and decreased continuously with increasing age, faster in the first few months and slower thereafter, until values achieved between 95 and 110 milliseconds for WM and 88 and 95 milliseconds for GM in adults. The relationship between T2 values and age could be well simulated using a biexponential function (R2 > 0.92). Conclusions:T2 relaxation time correlates well with the progress of brain maturation. The used biexponential function reflects the dynamic development of myelination in newborns and young children as well as the maturation of myelination during adolescence and could be used to develop a “normal” reference for neuroradiological diagnoses.

Age-Dependent Normal Values of T2* and T2′ in Brain Parenchyma

BACKGROUND AND PURPOSE: Physiologic age-related T2* and T2′ values are required as reference for comparison with disease-related deviations. In our study, T2* and T2′ values (T2 values as control) were determined with MR imaging in healthy subjects to determine standard values and investigate age-related changes. MATERIALS AND METHODS: Data of 50 patients without intraparenchymal pathology and 10 acute stroke patients who underwent MR imaging including a T2 and T2* sequence with 3 echotimes were included. After calculation of T2*, T2′, and T2 maps, the values of gray matter (GM) and white matter (WM) for each hemisphere were measured in 6 distinct regions of interest (ROIs). RESULTS: There was a negative correlation between age and T2* values in the caudate nucleus (r = −0.34 Pearson correlation; P = .001) and lentiform nucleus (r = −0.67; P = .001) and a positive correlation in the occipital (r = 0.41; P = .001) and subcortical (r = 0.45; P = .001) WM. An age dependency for T2′ values was only found for the caudate (r = −0.35; P = .001) and lentiform nucleus (r = −0.69; P = .001). T2′ values in acute stroke were lower than normal in all patients with stroke. CONCLUSION: Decrease in T2′ and T2* values in GM and increase of T2* values in WM correlate with the progress of brain aging. Explanations for decreasing T2′ and T2* values include iron deposition in the caudate and lentiform nucleus. In contrast to T2* values, there is no association of T2′ values with the degree of leukoaraiosis. These age-dependent values can be used as a reference in neurovascular diseases and for the discussion of functional MR imaging data.

Stabilization of juvenile metachromatic leukodystrophy after bone marrow transplantation: a 13-year follow-up.

A 29-year-old female patient with juvenile metachromatic leukodystrophy diagnosed at age 14 years received a bone marrow transplant at age 16 years. A report was published 6 years after bone marrow transplantation concluding that the disease had slowly progressed in the 2 years following bone marrow transplantation. We now report on a further 7-year follow-up, typified by a steady state of spastic paraplegia and mild dementia. Neurophysiological, neuroradiological, and psychological status also remained stable. In the patients leukocytes, the activity of arylsulfatase A, the enzyme deficient in untreated metachromatic leukodystrophy, was within the normal range whereas urinary sulfatides remained elevated. Data on the natural course of juvenile metachromatic leukodystrophy are rare, so in the present case it is difficult to establish whether the rather favorable course can be attributed with certainty to bone marrow transplantation. The long-term stabilization in this patient, however, suggested that bone marrow transplantation may halt the progression of juvenile metachromatic leukodystrophy.

MRI abnormalities in normal-appearing brain tissue of treated adult PKU patients.

To detect possible subclinical pathological brain changes a study on adult phenylketonuria (PKU) patients by using quantitative MRI methods was performed, since neuropsychological and cognitive deficits in treated patients with PKU have not yet been shown to correlate clearly with the brain lesions identified by conventional MRI.

Evidence of Rapid Ongoing Brain Development Beyond 2 Years of Age Detected by Fiber Tracking

BACKGROUND AND PURPOSE: Development of callosal fibers is important for psychomotor and cognitive functions. We hypothesized that brain maturation changes are detectable beyond 2 years of age by using diffusion tensor imaging (DTI) of the corpus callosum (CC). MATERIALS AND METHODS: T2 and fractional anisotropy (FA) maps of the brain of 55 healthy subjects between 0.2 and 39 years of age were obtained. Quantitative T2 and FA values were measured at the genu and splenium of the CC (gCC and sCC). Fiber tracking, volumetric determination, and the fiber density calculations of the CC were related to age. A paired t test was used for significant differences between the values at the gCC and sCC. RESULTS: T2 relaxation times at gCC and sCC decrease fast in the first months of life and very little after 2 years of age. The FAgCC increases until 5 years of age and remains nearly constant thereafter; it showed a significant increase from 0 to 2 years versus 2–5 years, whereas there was no difference in the other age groups. FAsCC values showed no significant changes after 2 years of age. The fiber density of the CC shows a tendency of inverse age dependence from childhood to adulthood. CONCLUSION: Rapid ongoing changes in brain maturation (increase in FAgCC) are detectable until 5 years of age. DTI reveals more information about brain maturation than T2 relaxometry.

Reproducibility and reliability of short-TE whole-brain MR spectroscopic imaging of human brain at 3T

A feasibility study of an echo‐planar spectroscopic imaging (EPSI) using a short echo time (TE) that trades off sensitivity, compared with other short‐TE methods, to achieve whole brain coverage using inversion recovery and spatial oversampling to control lipid bleeding.

MRI Features of Pontine Autosomal Dominant Microangiopathy and Leukoencephalopathy (PADMAL)

Cerebral small vessel disease is a topic of growing interest for both the scientific community and the aging society. We report the magnetic resonance imaging (MRI) characteristics of a recently found autosomal dominantly inherited microangiopathy.

Value of quantitative analysis of routine clinical MRI sequences in ALS

Abstract Simple morphological assessment of conventional MRI used in routine neurological diagnostic work-up lacks sensitivity and specificity for amyotrophic lateral sclerosis (ALS). Quantitative analysis of routine MRI sequences might, however, be more suitable to reveal ALS-related pathological cerebral alterations. We investigated 10 ALS patients and 10 age- and sex-matched healthy controls by MRI. Brain maps of T2 relaxation time (T2), relative proton density (PD), and apparent diffusion coefficient (ADC) were obtained. Values of these parameters were measured in 22 selected brain regions, and compared among the patients and the controls by using paired t-test with Bonferroni corrected alpha level (= 0.002). In ALS patients, increased PD was found in the pyramidal tract, corpus callosum, and white and grey matter. T2 elongation was found at the genu of corpus callosum, and at the posterior limb of the internal capsule (ICP). ADC values showed a tendency towards an increase in patients, which was only significant at the ICP. PD therefore appeared to be the most sensitive parameter for the detection of degenerative changes not only in the motor system but also in extramotor brain regions.

HAX1 mutations causing severe congenital neuropenia and neurological disease lead to cerebral microstructural abnormalities documented by quantitative MRI.

Biallelic mutations in the gene encoding HCLS‐associated protein X‐1 (HAX1) cause autosomal recessive severe congenital neutropenia (SCN). Some of these patients have neurological abnormalities including developmental delay, cognitive impairment, and/or epilepsy. Recent genotype–phenotype studies have shown that mutations in HAX1 affecting transcripts A (NM_006118.3) and B (NM_001018837.1) cause the phenotype of SCN with neurological impairment, while mutations affecting isoform A but not B lead to SCN without neurological aberrations. In this study, we identified a consanguineous family with two patients suffering from SCN and neurological disease caused by a novel, homozygous genomic deletion including exons 4–7 of the HAX1 gene. Quantitative MRI analyses showed generalized alterations in cerebral proton density in both of the patients, as well as in an additional unrelated patient with another HAX1 mutation (Arg86X) known to be associated with neurological manifestations. This study provides first in vivo evidence of aberrant neuroimaging findings associated with HAX1 deficiency in SCN patients.

Long‐term neuroimaging follow‐up on an asymptomatic juvenile metachromatic leukodystrophy patient after hematopoietic stem cell transplantation: Evidence of myelin recovery and ongoing brain maturation

Long-Term Neuroimaging Follow-Up on an Asymptomatic Juvenile Metachromatic Leukodystrophy Patient After Hematopoietic Stem Cell Transplantation: Evidence of Myelin Recovery and Ongoing Brain Maturation Xiao-Qi Ding,* Annette Bley, Alfried Kohlsch€utter, Jens Fiehler, and Heinrich Lanfermann Institute of Diagnostic and Interventional Neuroradiology, Hannover Medical School, Hannover, Germany Department of Pediatrics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany Department of Neuroradiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany