Effects of early life stress on depression, cognitive performance and brain morphology.

BACKGROUND: Childhood early life stress (ELS) increases risk of adulthood major depressive disorder (MDD) and is associated with altered brain structure and function. It is unclear whether specific ELSs affect depression risk, cognitive function and brain structure. METHOD: This cross-sectional study included 64 antidepressant-free depressed and 65 never-depressed individuals. Both groups reported a range of ELSs on the Early Life Stress Questionnaire, completed neuropsychological testing and 3T magnetic resonance imaging (MRI). Neuropsychological testing assessed domains of episodic memory, working memory, processing speed and executive function. MRI measures included cortical thickness and regional gray matter volumes, with a priori focus on the cingulate cortex, orbitofrontal cortex (OFC), amygdala, caudate and hippocampus. RESULTS: Of 19 ELSs, only emotional abuse, sexual abuse and severe family conflict independently predicted adulthood MDD diagnosis. The effect of total ELS score differed between groups. Greater ELS exposure was associated with slower processing speed and smaller OFC volumes in depressed subjects, but faster speed and larger volumes in non-depressed subjects. In contrast, exposure to ELSs predictive of depression had similar effects in both diagnostic groups. Individuals reporting predictive ELSs exhibited poorer processing speed and working memory performance, smaller volumes of the lateral OFC and caudate, and decreased cortical thickness in multiple areas including the insula bilaterally. Predictive ELS exposure was also associated with smaller left hippocampal volume in depressed subjects. CONCLUSIONS: Findings suggest an association between childhood trauma exposure and adulthood cognitive function and brain structure. These relationships appear to differ between individuals who do and do not develop depression.

Quantitative Evaluation of Medial Temporal Lobe Morphology in Children with Febrile Status Epilepticus: Results of the FEBSTAT Study.

BACKGROUND AND PURPOSE: The pathogenesis of febrile status epilepticus is poorly understood, but prior studies have suggested an association with temporal lobe abnormalities, including hippocampal malrotation. We used a quantitative morphometric method to assess the association between temporal lobe morphology and febrile status epilepticus. MATERIALS AND METHODS: Brain MR imaging was performed in children presenting with febrile status epilepticus and control subjects as part of the Consequences of Prolonged Febrile Seizures in Childhood study. Medial temporal lobe morphologic parameters were measured manually, including the distance of the hippocampus from the midline, hippocampal height:width ratio, hippocampal angle, collateral sulcus angle, and width of the temporal horn. RESULTS: Temporal lobe morphologic parameters were correlated with the presence of visual hippocampal malrotation; the strongest association was with left temporal horn width (P < .001; adjusted OR, 10.59). Multiple morphologic parameters correlated with febrile status epilepticus, encompassing both the right and left sides. This association was statistically strongest in the right temporal lobe, whereas hippocampal malrotation was almost exclusively left-sided in this cohort. The association between temporal lobe measurements and febrile status epilepticus persisted when the analysis was restricted to cases with visually normal imaging findings without hippocampal malrotation or other visually apparent abnormalities. CONCLUSIONS: Several component morphologic features of hippocampal malrotation are independently associated with febrile status epilepticus, even when complete hippocampal malrotation is absent. Unexpectedly, this association predominantly involves the right temporal lobe. These findings suggest that a spectrum of bilateral temporal lobe anomalies are associated with febrile status epilepticus in children. Hippocampal malrotation may represent a visually apparent subset of this spectrum.

SU-D-BRB-06: Comprehensive Population-Averaged Arterial Input Function (AIF) for DCE-MRI of Head and Neck Cancer.

PURPOSE: To generate a composite population-averaged(PA)-AIF for quantitative analysis of DCE-MRI data in head and neck (H&N) patients that is based on the right (RT) and left (LT) carotids, two pre-treatment scans, and one post-treatment scan. METHODS: Twenty patients were imaged while undergoing concurrent chemoradiation (CRT) for H&N malignancies. The imaging protocol (1) included two baseline scans one week apart (Base1, Base2), and one scan 1 week post-CRT (Post). For each patient and time point, regions of interest (ROIs) in both the RT and LT carotids were drawn on coronal images. The plasma concentration curves of all ROIs were averaged and fit to a bi-exponential decay function to obtain the final PA- AIF (AvgAll). The ROIs were also divided by time point to obtain AvgBasel, AvgBase2, and AvgPost AIFs. The vascular transfer constant for both primary and nodes, Ktrans , was calculated (iCAD, Inc.) using the 4 AIFs, as well as the generic Weinmann's AIF. The median Ktrans values resulting from the AvgAll AIF were compared using Bland-Altman plots with the ones obtained from each individual time point. The Wilcoxon signed-rank test was used to compare the proposed AvgAll AIF and the generic AIF. RESULTS: The plasma parameters for the AvgAll AIF were a1,2=27.1135/17.6486 kg/liter, m 1,2=11.7525/0.2054 min-1 . The differences in Ktrans values using these coefficients vs. Weinmann's were statistically significant (p<0.0001). The median Ktrans values from the AvgBasel,AvgBase2, and AvgPost AIFs were, in most cases, not significantly different from the AvgAll values, indicating that the latter is appropriate foruse at all time points. CONCLUSIONS: A population-averaged AIF for H&N was generated that accounts for differences in RT vs. LT carotids, day-today AIF fluctuations, and treatment-induced AIF changes. It is not necessary to measure a post-treatment AIF to evaluate treatment-induced Ktrans changes.l. Craciunescu et al., MedPhys, 37, 6, 2683, 2010.

BDNF Val66Met genotype and 6-month remission rates in late-life depression.

Although not observed in younger adult cohorts, in older individuals the brain-derived neurotrophic factor (BDNF) Val66Met polymorphism is associated with major depressive disorder (MDD) risk. It is further associated with subjective social support and magnetic resonance imaging (MRI) hyperintense lesions, clinical features independently related to MDD. We examined the relationship between this polymorphism and antidepressant remission rates in an elderly sample with MDD, while also testing for mediation effects of social support and hyperintensities. A total of 229 elderly Caucasian subjects with MDD completed baseline assessments, 1.5 T MRI, and BDNF genotyping. They received antidepressant medication under a structured treatment algorithm and were evaluated for remission at 3 and 6 months. At the 3-month evaluation, BDNF Val66Met genotype was not associated with remission (Wald's χ²=2.51, P=0.1131). When not controlling for multiple comparisons, Met66 allele carriers were more likely to be remitted at 6 months (χ²=4.32, P=0.0377) with an odds ratio of 1.82 (95% CI: 1.04, 3.22). This effect persisted after controlling for lesion volume and social support, neither of which mediated this relationship. Thus in this exploratory analysis, the Met66 allele may be associated with increased odds of remission in older subjects, but also with increased time to remission as there was no 3-month effect.

Angiotensin receptor gene polymorphisms and 2-year change in hyperintense lesion volume in men.

This longitudinal study examined the relationship between 2-year change in white matter hyperintense lesion (WML) volume and polymorphisms in genes coding for the angiotensin-II type 1 and type 2 receptors, AGTR1 A1166C and AGTR2 C3123A, respectively. 137 depressed and 94 non-depressed participants aged >or=60 years were enrolled. Standard clinical evaluations were performed on all participants and blood samples obtained for genotyping. 1.5-T MRI (magnetic resonance imaging) data were obtained at baseline and approximately 2 years later. These scans were processed using a semi-automated segmentation process, which allowed for the calculation of WML volume at each time point. Statistical models were tested for the relationship between change in WML volume and genotype, while also controlling for age, sex, diagnostic strata, baseline WML volume and comorbid cerebrovascular risk factors. In men, AGTR1 1166A allele homozygotes exhibited significantly less change in WML volume than 1166C carriers. We also found that men reporting hypertension (HTN) with the AGTR2 3123C allele exhibit less change in WML volume than hypertensive men with the 3123A allele, or men without HTN. There were no significant relationships between these polymorphisms and change in WML volume in women. No significant gene-gene or gene-depression interactions were observed. Our results parallel earlier observed gender differences of the relationship between other renin-angiotensin system polymorphisms and HTN. Further work is needed to determine whether these observed relationships are secondary to polymorphisms affecting response to antihypertensive medication, and whether antihypertensive medications can slow WML progression and lower the risk of morbidity associated with WMLs.

Clinical Utility of Magnetic Resonance Thermal Imaging (MRTI) For Realtime Guidance of Deep Hyperthermia.

A critical need has emerged for volumetric thermometry to visualize 3D temperature distributions in real time during deep hyperthermia treatments used as an adjuvant to radiation or chemotherapy for cancer. For the current effort, magnetic resonance thermal imaging (MRTI) is used to measure 2D temperature rise distributions in four cross sections of large extremity soft tissue sarcomas during hyperthermia treatments. Novel hardware and software techniques are described which improve the signal to noise ratio of MR images, minimize motion artifact from circulating coupling fluids, and provide accurate high resolution volumetric thermal dosimetry. For the first 10 extremity sarcoma patients, the mean difference between MRTI region of interest and adjacent interstitial point measurements during the period of steady state temperature was 0.85°C. With 1min temporal resolution of measurements in four image planes, this non-invasive MRTI approach has demonstrated its utility for accurate monitoring and realtime steering of heat into tumors at depth in the body.

Evidence of white matter tract disruption in MRI hyperintensities.

BACKGROUND: Diffusion tensor imaging (DTI) of brain tissue measures the apparent diffusion coefficient (ADC), or isotropic diffusion, and anisotropy, or diffusion as influenced by tissue structure. We hypothesized that hyperintensities, when compared with normal tissue by DTI, would show evidence of damage through an increased ADC and decreased anisotropy. We also hypothesized that DTI changes in hyperintensities would be similar between depressed subjects and control subjects. METHODS: Fourteen depressed geriatric patients and nineteen control subjects received DTI. The ADC and aniso-tropy of normal tissue from standard regions were compared with hyperintensities from these regions. The Students' t test compared individual regions and averaged white matter results. RESULTS: Hyperintensities showed higher ADC and lower anisotropy than normal regions. Gray matter exhibited similar trends. There was no significant difference in diffusion characteristics of hyperintensities between subjects and control subjects. CONCLUSIONS: Hyperintensities damage the structure of brain tissue, and do so comparably in depressed subjects and control subjects.

Medial orbital frontal lesions in late-onset depression.

BACKGROUND: Early studies using magnetic resonance (MR) imaging suggested that subcortical vascular changes are more prevalent in late-life depression and that they may play a role in the pathophysiology of depression. Studying the location of the lesion relative to the occurrence of depression could be critical in delineating the neuroanatomic substrates of depression. Our purpose was to characterize these lesions in terms of location by development of statistical parametric maps of lesions that differentiate patients from control subjects. METHODS: Magnetic resonance images were acquired on 88 elderly depressed subjects ("patients," unipolar major depression assessed using the Duke Depression Evaluation Schedule, age range 63-80 years) enrolled in the Duke University Clinical Research Center for the Study of Late-Life Depression and 47 age- and gender-matched nondepressed subjects ("control subjects"). The MR protocol includes a volumetric, dual-contrast fast spin-echo pulse sequence. A statistical parametric map was formed from a two-group t test to test for differences in lesion density between patients and control subjects. Additional testing was performed to evaluate whether there were regions that correlated with the severity of depression using the 17-item Hamilton Depression rating. RESULTS: The statistical parametric mapping analysis between groups showed two major regions of increased lesion density in the patients in the medial orbital prefrontal white matter. Severity of depression among depressed patients was correlated with lesions in the medial orbital region. CONCLUSIONS: This study supports recent evidence implicating the medial orbital frontal cortex in depression.

3D numerical reconstruction of the hyperthermia induced temperature distribution in human sarcomas using DE-MRI measured tissue perfusion: validation against non-invasive MR temperature measurements.

Essential to the success of optimized thermal treatment during hyperthermia is accurate modelling. Advection of energy due to blood perfusion significantly affects the temperature. Without accurate estimates of the magnitude of the local tissue blood perfusion, accurate estimates of the temperature distribution can not be made. It is shown here that the blood mass flow rate per unit volume of tissue in the Pennes' bio-heat equation can be modelled using a relative perfusion index (RPI) determined with dynamic-enhanced magnetic resonance imaging (DE-MRI). Temperature distributions in two patients treated with hyperthermia at Duke University Medical Center for high-grade leg tissue sarcomas are modelled, and the resultant temperatures are compared to measured temperatures using a non-invasive MR thermometry technique. Significant correlations are found between the DE-MRI perfusion images, the MR temperature images, and the numerical simulation of the temperature field. The correlation between DE-MRI measured values and advective heat loss in tissue is used to scale the perfusion distribution, thereby allowing the continuum model to account for the local thermal impact of vasculature in the tumour. Large vessels in tumour and neighbouring healthy tissue need to be taken into account in order to accurately describe the complete temperature distribution.

Use of exponential diffusion imaging to determine the age of ischemic infarcts.

OBJECTIVE: Diffusion-weighted magnetic resonance imaging (DWI) detects acute ischemic infarcts with high lesion conspicuity. Determination of infarct age is difficult on DWI alone because infarct signal intensity (SIinfarct) on DWI is influenced by T2 properties ("T2 shine-through"). Maps of the apparent diffusion coefficient (ADC) reflect pure diffusion characteristics without T2 effects but have low lesion conspicuity. Thus, in clinical practice, combined use of DWI and ADC maps is required. Exponential DWI (eDWI) is an innovative means of MRI-diffusion data analysis that merges the advantages of DWI and ADC maps. The authors hypothesized that SIinfarct on eDWI would correlate with infarct age. The authors studied 114 consecutive patients who had 120 ischemic strokes with clearly determined onset times and who underwent echo-planar DWI. The eDWI were generated by dividing the signal intensity on DWI by that on the corresponding T2 image on a pixel-by-pixel basis. SIinfarct on eDWI was measured in the lesion core and expressed as a percentage of contralateral control tissue. On eDWI, relative SIinfarct changed significantly with infarct age (P < .0001). When patients were sorted in infarct-age groups, no significant differences were found within the first 120 hours. However, for patients studied within 5 days, the mean relative SIinfarct was significantly higher compared with patients studied > or = 8 days after stroke (P < .05). For all infarcts up to 5 days old, the eDWI signal intensity was higher than control tissue (hyperintense appearance). All infarcts > 10 days old had an eDWI signal intensity lower than control tissue (hypointense appearance). The authors concluded that the use of eDWI, as a single set of images, reliably differentiates acute infarcts (< or = 5 days old) from infarcts > 10 days old. This feature would be expected to be helpful when the distinction between acute and nonacute infarction cannot be determined on clinical grounds.

Increased brain apparent diffusion coefficient in children with neurofibromatosis type 1.

PURPOSE: To describe the changes in brain water diffusibility in five anatomic locations in children with neurofibromatosis type 1 (NF 1) compared with these changes in control subjects and to describe the water diffusibility changes associated with hyperintense basal ganglia lesions in children with NF 1. MATERIALS AND METHODS: Twenty highly related pairs of children consisting of one child with NF 1 and one unaffected child were examined. Prospective comparisons of isotropic apparent diffusion coefficient (ADC) values at five anatomic locations were performed, with and without T2-hyperintense lesions included. Retrospective analysis of hyperintense globus pallidus lesions in 16 children and in the paired control subjects also was performed. RESULTS: Significant increases in ADC values were seen in all five anatomic locations in the NF 1 group. The greatest increases were seen in the globus pallidus (14%; P =.002) and brachium pontis (10.8%; P =.003). With exclusion of hyperintense lesions, significant ADC increases were measured in four locations. Significant ADC increases were seen in hyperintense globus pallidus lesions in the NF 1 group compared with ADC values in the normal-appearing contralateral globus pallidus (4.9%; P =.02) and those in the globus pallidus of the paired control subjects (16%; P =.003). CONCLUSION: Significant ADC increases were measured both in the hyperintense lesions and in the normal-appearing areas of the brain in children with NF 1.

Correction of MR kappa-space data corrupted by spike noise.

Magnetic resonance images are reconstructed from digitized raw data, which are collected in the spatial-frequency domain (also called kappa-space). Occasionally, single or multiple data points in the k-space data are corrupted by spike noise, causing striation artifacts in images. Thresholding methods for detecting corrupted data points can fail because of small alterations, especially for data points in the low spatial frequency area where the k-space variation is large. Restoration of corrupted data points using interpolations of neighboring pixels can give incorrect results. We propose a Fourier transform method for detecting and restoring corrupted data points using a window filter derived from the striation-artifact structure in an image or an intermediate domain. The method provides an analytical solution for the alteration at each corrupted data point. It can effectively restore corrupted kappa-space data, removing striation artifacts in images, provided that the following three conditions are satisfied. First, a region of known signal distribution (for example, air background) is visible in either the image or the intermediate domain so that it can be selected using a window filter. Second, multiple spikes are separated by the full-width at half-maximum of the point spread function for the window filter. Third, the magnitude of a spike is larger than the minimum detectable value determined by the window filter and the standard deviation of kappa-space random noise.

The effect of aging on the apparent diffusion coefficient of normal-appearing white matter.

OBJECTIVE: The purpose of our study was to test the hypothesis that the apparent diffusion coefficient (ADC) of normal-appearing white matter increases with advancing age. SUBJECTS AND METHODS: We selected 38 patients with normal MR imaging findings from 332 patients undergoing clinical MR imaging. Diffusion-weighted MR imaging was performed with diffusion gradients applied in three orthogonal directions. For each patient, the average ADC on trace-weighted diffusion images of white matter at prespecified regions of interest and at the thalamus were compared with the patient's age. RESULTS: For the white matter, ADC sorted by patient age in decades increased with advancing age. Patients at least 60 years old had significantly higher ADC (0.769 +/- 0.019 mm(2)/sec x 10(-3)) than patients less than 60 years old (0.740 +/- 0.013 mm(2)/sec x 10(-3)) (p < 0.001). Comparison of individual white matter ADC and age showed a significant increase with advancing age (p < 0.0001). For the thalamus, the average ADC among patients at least 60 years old (0.766 +/- 0.015 mm(2)/sec x 10(-3)) exceeded the average ADC for patients less than 60 years old (0.745 +/- 0.022 mm(2)/sec x 10(-3)) (p < 0.05). However, comparison of individual thalamic ADC and patient ages, although showing a trend to higher ADC with increasing age, did not reach statistical significance (p = 0.06). CONCLUSION: Advancing age is associated with a small but statistically significant increase of water diffusibility in human white matter. A similar trend was present in the thalamus. These increases may reflect mild structural changes associated with normal aging.

Hippocampal volume in geriatric depression.

BACKGROUND: There is a growing literature on the importance of hippocampal volume in geriatric depression. METHODS: We examined hippocampal volume in a group of elderly depressed patients and a group of elderly control subjects (N = 66 geriatric depressed patients and 18 elderly nondepressed control subjects) recruited through Duke's Mental Health Clinical Research Center for the Study of Depression in the Elderly. The subjects received a standardized evaluation, including a magnetic resonance imaging scan of the brain. Patients had unipolar major depression and were free of comorbid major psychiatric illness and neurologic illness. Differences were assessed using t tests and linear regression modeling. RESULTS: Accounting for the effects of age, gender, and total brain volume, depressed patients tended to have smaller right hippocampal volume (p =.014) and left hippocampal volume (p =.073). Among depressed patients, age of onset was negatively but not significantly related to right hippocampal volume (p =.052) and to left hippocampal volume (p =.062). We noted that among subjects with either right or left hippocampal volume of 3 mL or less, the vast majority were patients rather than control subjects. CONCLUSIONS: These results support a role for hippocampal dysfunction in depression, particularly in late-age onset depression. Longitudinal studies examining both depressive and cognitive outcomes are needed to clarify the relationships between the hippocampus, depression, and dementia.

Perturbations in hyperthermia temperature distributions associated with counter-current flow: numerical simulations and empirical verification.

Two numerical techniques are used to calculate the effect of large vessel counter-current flow on hyperthermic temperature distributions. One is based on the Navier-Stokes equation for steady-state flow, and the second employs a convective-type boundary condition at the interface of the vessel walls. Steady-state temperature fields were calculated for two energy absorption rate distributions (ARD) in a cylindrical tissue model having two pairs of counter-current vessels (one pair with equal diameter vessels and another pair with unequal diameters). The first assumed a uniform ARD throughout cylinder; the second ARD was calculated for a tissue cylinder inside an existing four antenna Radiofrequency (RF) array. A tissue equivalent phantom was constructed to verify the numerical calculations. Temperatures induced with the RF array were measured using a noninvasive magnetic resonance imaging technique based on the chemical shift of water. Temperatures calculated using the two numerical techniques are in good agreement with the measured data. The results show: 1) the convective-type boundary condition technique reduces computation time by a factor of ten when compared to the fully conjugated method with little quantitative difference (approximately 0.3 degree C) in the numerical accuracy and 2) the use of noninvasive magnetic resonance imaging (thermal imaging) to quantitatively access the temperature perturbations near large vessels is feasible using the chemical shift technique.

Novel techniques for MR imaging of pulmonary airspaces.

Hyperpolarized gas- and molecular oxygen-enhanced MR imaging are two new techniques for high-resolution MR imaging of pulmonary airspaces. Both techniques produce excellent images in a safe, reproducible, and technically feasible manner. Because morphologic and functional information is obtained, and radiation is not used, these techniques may prove ideal for serially evaluating patients with a variety of lung diseases that affect pulmonary ventilation, such as cystic fibrosis, emphysema, asthma, or bronchiolitis obliterans syndrome in lung transplant recipients. At present, the greatest clinical experience is with hyperpolarized He-3-enhanced MR imaging. This technique is limited, however, by the limited availability of He-3, by its polarization requirements, and by the need to tune the MR system to the resonant frequency of the gas. There is less clinical experience with oxygen-enhanced MR imaging. Although this technique produces images with more inherent noise than hyperpolarized He-3 imaging, this problem can be overcome by signal averaging. Oxygen-enhanced imaging has the major advantages of lower cost and ready availability. For oxygen-enhanced imaging, the MR imaging system does not need to be readjusted; imaging is performed at the conventional hydrogen proton frequency.

Temperature-dependent changes in physiologic parameters of spontaneous canine soft tissue sarcomas after combined radiotherapy and hyperthermia treatment.

PURPOSE: The objectives of this study were to evaluate effects of hyperthermia on tumor oxygenation, extracellular pH (pHe), and blood flow in 13 dogs with spontaneous soft tissue sarcomas prior to and after local hyperthermia. METHODS AND MATERIALS: Tumor pO2 was measured using an Eppendorf polarographic device, pHe using interstitial electrodes, and blood flow using contrast-enhanced magnetic resonance imaging (MRI). RESULTS: There was an overall improvement in tumor oxygenation observed as an increase in median pO2 and decrease in hypoxic fraction (% of pO2 measurements <5 mm Hg) at 24-h post hyperthermia. These changes were most pronounced when the median temperature (T50) during hyperthermia treatment was less than 44 degrees C. Tumors with T50 > 44 degrees C were characterized by a decrease in median PO2 and an increase in hypoxic fraction. Similar thermal dose-related changes were observed in tumor perfusion. Perfusion was significantly higher after hyperthermia. Increases in perfusion were most evident in tumors with T50 < 44 degrees C. With T50 > 44 degrees C, there was no change in perfusion after hyperthermia. On average, pHe values declined in all animals after hyperthermia, with the greatest reduction seen for larger T50 values. CONCLUSION: This study suggests that hyperthermia has biphasic effects on tumor physiologic parameters. Lower temperatures tend to favor improved perfusion and oxygenation, whereas higher temperatures are more likely to cause vascular damage, thus leading to greater hypoxia. While it has long been recognized that such effects occur in rodent tumors, this is the first report to tie such changes to temperatures achieved during hyperthermia in the clinical setting. Furthermore, it suggests that the thermal threshold for vascular damage is higher in spontaneous tumors than in more rapidly growing rodent tumors.

Magnetic resonance assessment of cerebral perfusion in depressed cardiac patients: preliminary findings.

OBJECTIVE: The authors investigated the links between depression, cardiac disease, and microcirculatory cerebral blood flow (CBF). METHOD: A magnetic resonance imaging technique based on arterial spin tagging was used to estimate microcirculatory CBF in depressed (N = 5) and comparison (N = 14) elderly subjects with coronary artery disease. Signal intensity ratios corresponding to relative microcirculatory CBF were calculated for four regions on two axial images through the upper and lower halves of the lateral ventricles. RESULTS: On the superior image, estimates of microcirculatory CBF were statistically significantly lower on the left side in the depressed subjects than in the nondepressed group. When the ratios in the superior and inferior images were averaged, the depressed subjects had lower values for both left periventricular regions of interest and the parietal region. CONCLUSIONS: Despite the small study group and indirect estimates of blood flow, these preliminary findings suggest that a relative cerebral hypoperfusion may underlie depression in elderly cardiac patients.

Hyperpolarized 3He-enhanced MR imaging of lung transplant recipients: preliminary results.

OBJECTIVE: Bronchiolitis obliterans syndrome is the major cause of long-term graft failure in lung transplant recipients and may be partially reversible if diagnosed early and treated. Diagnosis is difficult because findings of transbronchial biopsy are often negative in patients with early disease. We are investigating a novel MR ventilation agent, hyperpolarized 3He, for evaluating ventilatory abnormalities in lung transplant recipients with suspected bronchiolitis obliterans syndrome. CONCLUSION: In this preliminary study, the extent of ventilatory defects revealed on 3He-enhanced MR images correlated with severity of bronchiolitis obliterans syndrome using an established clinical grading system. This new technique may hold potential for diagnosing bronchiolitis obliterans syndrome in lung transplant recipients.