Correction to: MRI assessment of the thigh musculature in dermatomyositis and healthy subjects using diffusion tensor imaging, intravoxel incoherent motion and dynamic DTI.

The original version of this article, published on 04 June 2018, unfortunately contained a mistake.

The 2018 rift eruption and summit collapse of Kilauea Volcano.

In 2018, Kilauea Volcano experienced its largest lower East Rift Zone (LERZ) eruption and caldera collapse in at least 200 years. After collapse of the Pu'u 'O'o vent on 30 April, magma propagated downrift. Eruptive fissures opened in the LERZ on 3 May, eventually extending ~6.8 kilometers. A 4 May earthquake [moment magnitude (M w) 6.9] produced ~5 meters of fault slip. Lava erupted at rates exceeding 100 cubic meters per second, eventually covering 35.5 square kilometers. The summit magma system partially drained, producing minor explosions and near-daily collapses releasing energy equivalent to M w 4.7 to 5.4 earthquakes. Activity declined rapidly on 4 August. Summit collapse and lava flow volume estimates are roughly equivalent-about 0.8 cubic kilometers. Careful historical observation and monitoring of Kilauea enabled successful forecasting of hazardous events.

MRI assessment of the thigh musculature in dermatomyositis and healthy subjects using diffusion tensor imaging, intravoxel incoherent motion and dynamic DTI.

INTRODUCTION: Dermatomyositis (DM) is an idiopathic inflammatory myopathy involving severe debilitation in need of diagnostics. We evaluated the proximal lower extremity musculature with diffusion tensor imaging (DTI), intravoxel incoherent motion (IVIM) and dynamic DTI in DM patients and controls and compared with standard clinical workup. METHODS: In this IRB-approved, HIPAA-compliant study with written informed consent, anatomical, Dixon fat/water and diffusion imaging were collected in bilateral thigh MRI of 22 controls and 27 DM patients in a 3T scanner. Compartments were scored on T1/T2 scales. Single voxel dynamic DTI metrics in quadriceps before and after 3-min leg exercise were measured. Spearman rank correlation and mixed model analysis of variance/covariance (ANOVA/ANCOVA) were used to correlate with T1 and T2 scores and to compare patients with controls. RESULTS: DM patients showed significantly lower pseudo-diffusion and volume in quadriceps than controls. All subjects showed significant correlation between T1 score and signal-weighted fat fraction; tissue diffusion and pseudo-diffusion varied significantly with T1 and T2 score in patients. Radial and mean diffusion exercise response in patients was significantly higher than controls. CONCLUSION: Static and dynamic diffusion imaging metrics show correlation with conventional imaging scores, reveal spatial heterogeneity, and provide means to differentiate dermatomyositis patients from controls. KEY POINTS: • Diffusion imaging shows regional differences between thigh muscles of dermatomyositis patients and controls. • Signal-weighted fat fraction and diffusion metrics correlate with T1/T2 scores of disease severity. • Dermatomyositis patients show significantly higher radial diffusion exercise response than controls.

Specific MRI findings help distinguish acute transverse myelitis of Neuromyelitis Optica from spinal cord infarction.

BACKGROUND: There is substantial overlap between MRI of acute spinal cord lesions from neuromyelitis optica (NMO) and spinal cord infarct (SCI) in clinical practice. However, early differentiation is important since management approaches to minimize morbidity from NMO or SCI differ significantly. OBJECTIVE: To identify MRI features at initial presentation that may help to differentiate NMO acute myelitis from SCI. METHODS: 2 board-certified neuroradiologists, blinded to final diagnosis, retrospectively characterized MRI features at symptom onset for subjects with serologically-proven NMO (N=13) or SCI (N=11) from a single institution. Univariate and multivariate analyses were used to identify factors associated with NMO or SCI. RESULTS: SCI was more common in men and Caucasians, while NMO was more common in non-Caucasian women (P<0.05). MRI features associated with NMO acute myelitis (P<0.05) included location within 7-cm of cervicomedullary junction; lesion extending to pial surface; 'bright spotty lesions' on axial T2 MRI; and gadolinium enhancement. Patient's age, lesion length and cross-sectional area, cord expansion, and the "owl's eyes" sign did not differ between the two groups (P>0.05). CONCLUSION: Along with patient demographic characteristics, lesion features on MRI, including lesion location, extension to pial border and presence of 'bright spotty lesion' can help differentiate acute myelitis of NMO from SCI in the acute setting.

Metabolic Abnormalities in the Hippocampus of Patients with Schizophrenia: A 3D Multivoxel MR Spectroscopic Imaging Study at 3T.

BACKGROUND AND PURPOSE: Schizophrenia is well-known to be associated with hippocampal structural abnormalities. We used 1H-MR spectroscopy to test the hypothesis that these abnormalities are accompanied by NAA deficits, reflecting neuronal dysfunction, in patients compared with healthy controls. MATERIALS AND METHODS: Nineteen patients with schizophrenia (11 men; mean age, 40.6 ± 10.1 years; mean disease duration, 19.5 ± 10.5 years) and 11 matched healthy controls (5 men; mean age, 33.7 ± 10.1 years) underwent MR imaging and multivoxel point-resolved spectroscopy (TE/TR, 35/1400 ms) 1H-MRS at 3T to obtain their hippocampal GM absolute NAA, Cr, Cho, and mIns concentrations. Unequal variance t tests and ANCOVA were used to compare patients with controls. Bilateral volumes from manually outlined hippocampal masks were compared by using unequal variance t tests. RESULTS: Patients' average hippocampal GM Cr concentrations were 19% higher than that of controls, 8.7 ± 2.2 versus 7.4 ± 1.2 mmol/L (P < .05); showing no differences, concentrations in NAA were 8.8 ± 1.6 versus 8.7 ± 1.2 mmol/L; in Cho, 2.3 ± 0.7 versus 2.1 ± 0.3 mmol/L; and in mIns, 6.1 ± 1.5 versus 5.2 ± 0.9 (all P > .1). There was a positive correlation between mIns and Cr in patients (r = 0.57, P = .05) but not in controls. The mean bilateral hippocampal volume was ∼10% lower in patients: 7.5 ± 0.9 versus 8.4 ± 0.7 cm3 (P < .05). CONCLUSIONS: These findings suggest that the hippocampal volume deficit in schizophrenia is not due to net loss of neurons, in agreement with histopathology studies but not with prior 1H-MR spectroscopy reports. Elevated Cr is consistent with hippocampal hypermetabolism, and its correlation with mIns may also suggest an inflammatory process affecting some cases; these findings may suggest treatment targets and markers to monitor them.

Concurrent functional and metabolic assessment of brain tumors using hybrid PET/MR imaging.

To evaluate diagnostic accuracy of perfusion weighted imaging (PWI) and positron emission tomography (PET) using an integrated PET/MR system in tumor grading as well as in differentiating recurrent tumor from treatment-induced effects (TIE) in brain tumor patients. Twenty patients (Group A: treatment naïve, 9 patients with 16 lesions; Group B: post-therapy, 11 patients with 18 lesions) underwent fluorine 18 ((18)F) fluorodeoxyglucose (FDG) brain PET/MR with PWI. Two blinded readers predicted low versus high-grade tumor (for Group A) and tumor recurrence versus TIE (for Group B) based solely on tumor rCBV (regional cerebral blood volume) and SUV (standardized uptake values). Tumor histopathology at resection was the reference standard. Using rCBV(mean) ≤ 1.74 as a cut-off, 100% sensitivity and 74% specificity were observed, whereas 75% sensitivity and 89.7% specificity were observed with SUV(mean) ≤ 4.0 as a cut-off to classify patients as test positive for low-grade tumors (Group A) and TIE (Group B). Diagnostic accuracy for detection of low-grade tumors was 90% using PWI and 40% using PET in Group A (p = 0.056); for detection of TIE in Group B, diagnostic accuracy was 94.1% using PWI and 55.6% using PET (p = 0.033). No significant correlation was demonstrated between rCBV parameters and SUV in Group A (mean values: p > 0.403), Group B (p > 0.06) and in the entire population (p > 0.07). Best overall sensitivity and specificity were obtained using rCBV(mean) ≤ 1.74 and SUV(mean) ≤ 4.0 cut-off values. PWI demonstrated better diagnostic accuracy in both groups. Poor correlation was observed between FDG and rCBV parameters.

Does normalisation improve the diagnostic performance of apparent diffusion coefficient values for prostate cancer assessment? A blinded independent-observer evaluation.

AIM: To evaluate the performance of normalised apparent diffusion coefficient (ADC) values for prostate cancer assessment when performed by independent observers blinded to histopathology findings. MATERIALS AND METHODS: Fifty-eight patients undergoing 3 T phased-array coil magnetic resonance imaging (MRI) including diffusion-weighted imaging (DWI; maximal b-value 1000 s/mm(2)) before prostatectomy were included. Two radiologists independently evaluated the images, unaware of the histopathology findings. Regions of interest (ROIs) were drawn within areas showing visually low ADC within the peripheral zone (PZ) and transition zone (TZ) bilaterally. ROIs were also placed within regions in both lobes not suspicious for tumour, allowing computation of normalised ADC (nADC) ratios between suspicious and non-suspicious regions. The diagnostic performance of ADC and nADC were compared. RESULTS: For PZ tumour detection, ADC achieved significantly higher area under the receiver operating characteristic curve (AUC; p=0.026) and specificity (p=0.021) than nADC for reader 1, and significantly higher AUC (p=0.025) than nADC for reader 2. For TZ tumour detection, nADC achieved significantly higher specificity (p=0.003) and accuracy (p=0.004) than ADC for reader 2. For PZ Gleason score >3+3 tumour detection, ADC achieved significantly higher AUC (p=0.003) and specificity (p=0.005) than nADC for reader 1, and significantly higher AUC (p=0.023) than nADC for reader 2. For TZ Gleason score >3+3 tumour detection, ADC achieved significantly higher specificity (p=0.019) than nADC for reader 1. CONCLUSION: In contrast to prior studies performing unblinded evaluations, ADC was observed to outperform nADC overall for two independent observers blinded to the histopathology findings. Therefore, although strategies to improve the utility of ADC measurements in prostate cancer assessment merit continued investigation, caution is warranted when applying normalisation to improve diagnostic performance in clinical practice.

High-Resolution DCE-MRI of the Pituitary Gland Using Radial k-Space Acquisition with Compressed Sensing Reconstruction.

BACKGROUND AND PURPOSE: The pituitary gland is located outside of the blood-brain barrier. Dynamic T1 weighted contrast enhanced sequence is considered to be the gold standard to evaluate this region. However, it does not allow assessment of intrinsic permeability properties of the gland. Our aim was to demonstrate the utility of radial volumetric interpolated brain examination with the golden-angle radial sparse parallel technique to evaluate permeability characteristics of the individual components (anterior and posterior gland and the median eminence) of the pituitary gland and areas of differential enhancement and to optimize the study acquisition time. MATERIALS AND METHODS: A retrospective study was performed in 52 patients (group 1, 25 patients with normal pituitary glands; and group 2, 27 patients with a known diagnosis of microadenoma). Radial volumetric interpolated brain examination sequences with golden-angle radial sparse parallel technique were evaluated with an ROI-based method to obtain signal-time curves and permeability measures of individual normal structures within the pituitary gland and areas of differential enhancement. Statistical analyses were performed to assess differences in the permeability parameters of these individual regions and optimize the study acquisition time. RESULTS: Signal-time curves from the posterior pituitary gland and median eminence demonstrated a faster wash-in and time of maximum enhancement with a lower peak of enhancement compared with the anterior pituitary gland (P < .005). Time-optimization analysis demonstrated that 120 seconds is ideal for dynamic pituitary gland evaluation. In the absence of a clinical history, differences in the signal-time curves allow easy distinction between a simple cyst and a microadenoma. CONCLUSIONS: This retrospective study confirms the ability of the golden-angle radial sparse parallel technique to evaluate the permeability characteristics of the pituitary gland and establishes 120 seconds as the ideal acquisition time for dynamic pituitary gland imaging.

Early glial activation precedes neurodegeneration in the cerebral cortex after SIV infection: a 3D, multivoxel proton magnetic resonance spectroscopy study.

OBJECTIVES: As ∼40% of HIV-infected individuals experience neurocognitive decline, we investigated whether proton magnetic resonance spectroscopic imaging ((1) H-MRSI) detects early metabolic abnormalities in the cerebral cortex of a simian immunodeficiency virus (SIV)-infected rhesus monkey model of neuroAIDS. METHODS: The brains of five rhesus monkeys before and 4 or 6 weeks after SIV infection (with CD8(+) T-cell depletion) were assessed with T2 -weighted quantitative magnetic resonance imaging (MRI) and 16×16×4 multivoxel (1) H-MRSI (echo time/repetition time = 33/1440 ms). Grey matter and white matter masks were segmented from the animal MRIs and used to produce cortical masks co-registered to (1) H-MRSI data to yield cortical metabolite concentrations of the glial markers myo-inositol (mI), creatine (Cr) and choline (Cho), and of the neuronal marker N-acetylaspartate (NAA). The cortex volume within the large, 28 cm(3) (∼35% of total monkey brain) volume of interest was also calculated for each animal pre- and post-infection. Mean metabolite concentrations and cortex volumes were compared pre- and post-infection using paired sample t-tests. RESULTS: The mean (± standard deviation) pre-infection concentrations of the glial markers mI, Cr and Cho were 5.8 ± 0.9, 7.2 ± 0.4 and 0.9 ± 0.1 mM, respectively; these concentrations increased 28% (p ≈ 0.06), 15% and 10% (both p < 0.05), respectively, post-infection. The mean concentration of neuronal marker NAA remained unchanged (7.0 ± 0.6 mM pre-infection vs. 7.3 ± 0.8 mM post-infection; p ≈ 0.37). The mean cortex volume was also unchanged (8.1 ± 1.1 cm(3) pre-infection vs. 8.3 ± 0.5 cm(3) post-infection; p ≈ 0.76). CONCLUSIONS: These results support the hypothesis that early cortical glial activation occurs after SIV infection prior to the onset of neurodegeneration. This suggests HIV therapeutic interventions should potentially target early glial activation in the cerebral cortex.

Non-Gaussian diffusion MRI of gray matter is associated with cognitive impairment in multiple sclerosis.

BACKGROUND: Non-Gaussian diffusion imaging by using diffusional kurtosis imaging (DKI) allows assessment of isotropic tissue as of gray matter (GM), an important limitation of diffusion tensor imaging (DTI). OBJECTIVE: In this study, we describe DKI and DTI metrics of GM in multiple sclerosis (MS) patients and their association with cognitive deficits. METHODS: Thirty-four patients with relapsing-remitting MS and 17 controls underwent MRI on a 3T scanner including a sequence for DKI with 30 diffusion directions and 3b values for each direction. Mean kurtosis (MK), mean diffusivity and fractional anisotropy (FA) of cortical and subcortical GM were measured using histogram analysis. Spearman rank correlations were used to characterize associations among imaging measures and clinical/neuropsychological scores. RESULTS: In cortical GM, a significant decrease of MK (0.68 vs. 0.73; p < 0.001) and increase of FA (0.16 vs. 0.13; p < 0.001) was found in patients compared to controls. Decreased cortical MK was correlated with poor performance on the Delis-Kaplan Executive Function System test (r = 0.66, p = 0.01). CONCLUSION: Mean kurtosis is sensitive to abnormality in GM of MS patients and can provide information that is complementary to that of conventional DTI-derived metrics. The association between MK and cognitive deficits suggests that DKI might serve as a clinically relevant biomarker for cortical injury.

Performance of multidetector CT in the evaluation of the endometrium: Measurement of endometrial thickness and detection of disease.

AIM: To evaluate the performance of multidetector computed tomography (MDCT) in the measurement of endometrial thickness and assessment for endometrial disease. MATERIALS AND METHODS: Seventy-nine MDCT examinations, including sagittal reformats from isotropic data, were retrospectively evaluated for the presence of endometrial abnormality, endometrial thickness, and recommendation for transvaginal ultrasound (TVUS) after CT. The endometrial thickness was measured on sagittal images using two different methods, between the inner-to-inner hypoattenuating stripe, and when visible, between the outer-to-outer hyperattenuating stripe. TVUS performed within 48 h of CT in premenopausal and 1 month in postmenopausal patients served as reference standard. Interobserver agreement for endometrial thickness and abnormalities was assessed using concordance correlation (CC) and kappa statistics. RESULTS: Interobserver agreement for endometrial thickness on sagittal CT images was excellent (CC 0.98), and highly accurate using the inner-to-inner measurement. For determination of abnormal thickening, the positive predictive value and negative predictive value were 67-100% and 99.5-100%. For detection of any endometrial abnormality, the positive predictive value and negative predictive value were 79-90% and 84-95%, respectively. False-negative missed abnormalities included small volume hydrometra, a polyp, and endometrial distortion by a fibroid. CONCLUSION: At MDCT, sagittal reformatted images provide reliable endometrial measurement using the inner-to-inner hypoattenuating stripe and are accurately categorized as normal or abnormal thickness using the same numerical criteria as at sonography.

Detection of cartilage damage in femoroacetabular impingement with standardized dGEMRIC at 3 T.

OBJECTIVE: This study aimed at identifying the optimal threshold value to detect cartilage lesions with Standardized delayed Gadolinium-Enhanced MRI of Cartilage (dGEMRIC) at 3 T and evaluate intra- and inter-observer repeatability. DESIGN: We retrospectively reviewed 20 hips in 20 patients. dGEMRIC maps were acquired at 3 T along radial imaging planes of the hip and standardized to remove the effects of patient's age, sex and diffusion of gadolinium contrast. Two observers separately evaluated 84 Standardized dGEMRIC maps, both by visual inspection and using an average index for a region of interest (ROI) in the acetabular cartilage. A radiologist evaluated the acetabular cartilage on morphologic MR images at exactly the same locations. Using intra-operative findings as reference, the optimal threshold to detect cartilage lesions with Standardized dGEMRIC was assessed and results were compared with the diagnostic performance of morphologic magnetic resonance imaging (MRI). RESULTS: Using z < -2 as threshold and visual inspection of the color-adjusted maps, sensitivity, specificity and accuracy for Observer 1 and Observer 2, were 83%, 60% and 75%, and 69%, 70% and 69%, respectively. Overall performance was 52%, 67% and 58%, when using an average z for the acetabular cartilage, compared to 37%, 90% and 56% for morphologic assessment. The kappa coefficient was 0.76 and 0.68 for intra- and inter-observer repeatability, respectively, indicating substantial agreement. CONCLUSIONS: Standardized dGEMRIC at 3 T is accurate in detecting cartilage damage and could improve preoperative assessment in femoroacetabular impingement (FAI). As cartilage lesions in FAI are localized, visual inspection of the Standardized dGEMRIC maps is more accurate than an average z for the acetabular cartilage.

Novel white matter tract integrity metrics sensitive to Alzheimer disease progression.

BACKGROUND AND PURPOSE: Along with cortical abnormalities, white matter microstructural changes such as axonal loss and myelin breakdown are implicated in the pathogenesis of Alzheimer disease. Recently, a white matter model was introduced that relates non-Gaussian diffusional kurtosis imaging metrics to characteristics of white matter tract integrity, including the axonal water fraction, the intra-axonal diffusivity, and the extra-axonal axial and radial diffusivities. MATERIALS AND METHODS: This study reports these white matter tract integrity metrics in subjects with amnestic mild cognitive impairment (n = 12), Alzheimer disease (n = 14), and age-matched healthy controls (n = 15) in an effort to investigate their sensitivity, diagnostic accuracy, and associations with white matter changes through the course of Alzheimer disease. RESULTS: With tract-based spatial statistics and region-of-interest analyses, increased diffusivity in the extra-axonal space (extra-axonal axial and radial diffusivities) in several white matter tracts sensitively and accurately discriminated healthy controls from those with amnestic mild cognitive impairment (area under the receiver operating characteristic curve = 0.82-0.95), while widespread decreased axonal water fraction discriminated amnestic mild cognitive impairment from Alzheimer disease (area under the receiver operating characteristic curve = 0.84). Additionally, these white matter tract integrity metrics in the body of the corpus callosum were strongly correlated with processing speed in amnestic mild cognitive impairment (r = |0.80-0.82|, P < .001). CONCLUSIONS: These findings have implications for the course and spatial progression of white matter degeneration in Alzheimer disease, suggest the mechanisms by which these changes occur, and demonstrate the viability of these white matter tract integrity metrics as potential neuroimaging biomarkers of the earliest stages of Alzheimer disease and disease progression.

Distinct patterns of tissue-specific lipid accumulation during the induction of insulin resistance in mice by high-fat feeding.

AIMS/HYPOTHESIS: While it is well known that diet-induced obesity causes insulin resistance, the precise mechanisms underpinning the initiation of insulin resistance are unclear. To determine factors that may cause insulin resistance, we have performed a detailed time-course study in mice fed a high-fat diet (HFD). METHODS: C57Bl/6 mice were fed chow or an HFD from 3 days to 16 weeks and glucose tolerance and tissue-specific insulin action were determined. Tissue lipid profiles were analysed by mass spectrometry and inflammatory markers were measured in adipose tissue, liver and skeletal muscle. RESULTS: Glucose intolerance developed within 3 days of the HFD and did not deteriorate further in the period to 12 weeks. Whole-body insulin resistance, measured by hyperinsulinaemic-euglycaemic clamp, was detected after 1 week of HFD and was due to hepatic insulin resistance. Adipose tissue was insulin resistant after 1 week, while skeletal muscle displayed insulin resistance at 3 weeks, coinciding with a defect in glucose disposal. Interestingly, no further deterioration in insulin sensitivity was observed in any tissue after this initial defect. Diacylglycerol content was increased in liver and muscle when insulin resistance first developed, while the onset of insulin resistance in adipose tissue was associated with increases in ceramide and sphingomyelin. Adipose tissue inflammation was only detected at 16 weeks of HFD and did not correlate with the induction of insulin resistance. CONCLUSIONS/INTERPRETATION: HFD-induced whole-body insulin resistance is initiated by impaired hepatic insulin action and exacerbated by skeletal muscle insulin resistance and is associated with the accumulation of specific bioactive lipid species.

Long-range interactions of excited He atoms with the alkaline earth atoms Mg, Ca, and Sr.

Dispersion coefficients for the long-range interactions of the first four excited states of He, i.e., He(2 (1, 3)S) and He(2 (1, 3)P), with the low-lying states of the alkaline earth atoms Mg, Ca, and Sr are calculated by summing over the reduced matrix elements of multipole transition operators.

A better characterization of spinal cord damage in multiple sclerosis: a diffusional kurtosis imaging study.

BACKGROUND AND PURPOSE: The spinal cord is a site of predilection for MS lesions. While diffusion tensor imaging is useful for the study of anisotropic systems such as WM tracts, it is of more limited utility in tissues with more isotropic microstructures (on the length scales studied with diffusion MR imaging) such as gray matter. In contrast, diffusional kurtosis imaging, which measures both Gaussian and non-Gaussian properties of water diffusion, provides more biomarkers of both anisotropic and isotropic structural changes. The aim of this study was to investigate the cervical spinal cord of patients with MS and to characterize lesional and normal-appearing gray matter and WM damage by using diffusional kurtosis imaging. MATERIALS AND METHODS: Nineteen patients (13 women, mean age = 41.1 ± 10.7 years) and 16 controls (7 women, mean age = 35.6 ± 11.2-years) underwent MR imaging of the cervical spinal cord on a 3T scanner (T2 TSE, T1 magnetization-prepared rapid acquisition of gradient echo, diffusional kurtosis imaging, T2 fast low-angle shot). Fractional anisotropy, mean diffusivity, and mean kurtosis were measured on the whole cord and in normal-appearing gray matter and WM. RESULTS: Spinal cord T2-hyperintense lesions were identified in 18 patients. Whole spinal cord fractional anisotropy and mean kurtosis (P = .0009, P = .003), WM fractional anisotropy (P = .01), and gray matter mean kurtosis (P = .006) were significantly decreased, and whole spinal cord mean diffusivity (P = .009) was increased in patients compared with controls. Mean spinal cord area was significantly lower in patients (P = .04). CONCLUSIONS: Diffusional kurtosis imaging of the spinal cord can provide a more comprehensive characterization of lesions and normal-appearing WM and gray matter damage in patients with MS. Diffusional kurtosis imaging can provide additional and complementary information to DTI on spinal cord pathology.

Atypical incomplete femoral fractures in asymptomatic patients on long term bisphosphonate therapy.

OBJECTIVES: Progression of an incomplete atypical femoral fracture (IF) to a complete fracture in patients on long term bisphosphonate (BP) therapy can be catastrophic. We aimed to determine the frequency and imaging features of IF in asymptomatic patients on long-term BP therapy and to identify distinguishing clinical and laboratory markers in the subset of patients who develop these fractures. MATERIAL AND METHODS: From August 2009 to March 2011, 220 femoral radiographs in 110 asymptomatic patients (101 women, 9 men, age 47-94) were reviewed by 2 radiologists. All patients were on BP therapy for at least 3 years and had no history of hip/thigh pain or recent trauma. MRI was performed when a fracture was suspected on radiographs. Bone mineral density, serum calcium, 25-hydroxy vitamin D, intact parathyroid hormone, serum c-telopeptide and urine n-telopeptide were obtained in all patients. RESULTS: Two of 110 patients (1.82%, confidence interval of 0.6% to 6.3%) had 3 IFs. Both patients, age 50 and 57, were Caucasian, active and on BP for 8 years. MRI confirmed radiographic findings in both patients. Both women had T-scores in the osteopenic range at 2 sites and osteoporotic range at 1 site. CONCLUSION: The 1.82% frequency of IF in asymptomatic patients on long term BP therapy is higher than that suggested in the literature. Statistical differences between fracture and non-fracture groups were not presented as the patient population was too small to draw any significant conclusions.

Sex differences in activated corticotropin-releasing factor neurons within stress-related neurocircuitry and hypothalamic-pituitary-adrenocortical axis hormones following restraint in rats.

Women may be more vulnerable to certain stress-related psychiatric illnesses than men due to differences in hypothalamic-pituitary-adrenocortical (HPA) axis function. To investigate potential sex differences in forebrain regions associated with HPA axis activation in rats, these experiments utilized acute exposure to a psychological stressor. Male and female rats in various stages of the estrous cycle were exposed to 30min of restraint, producing a robust HPA axis hormonal response in all animals, the magnitude of which was significantly higher in female rats. Although both male and female animals displayed equivalent c-fos expression in many brain regions known to be involved in the detection of threatening stimuli, three regions had significantly higher expression in females: the paraventricular nucleus of the hypothalamus (PVN), the anteroventral division of the bed nucleus of the stria terminalis (BSTav), and the medial preoptic area (MPOA). Dual fluorescence in situ hybridization analysis of neurons containing c-fos and corticotropin-releasing factor (CRF) mRNA in these regions revealed significantly more c-fos and CRF single-labeled neurons, as well as significantly more double-labeled neurons in females. Surprisingly, there was no effect of the estrous cycle on any measure analyzed, and an additional experiment revealed no demonstrable effect of estradiol replacement following ovariectomy on HPA axis hormone induction following stress. Taken together, these data suggest sex differences in HPA axis activation in response to perceived threat may be influenced by specific populations of CRF neurons in key stress-related brain regions, the BSTav, MPOA, and PVN, which may be independent of circulating sex steroids.

Cognitive impairment in mild traumatic brain injury: a longitudinal diffusional kurtosis and perfusion imaging study.

BACKGROUND AND PURPOSE: Cognitive impairment is frequent among patients with mild traumatic brain injury despite the absence of detectable damage on conventional MR imaging. In this study, the quantitative MR imaging techniques DTI, DKI, and ASL were used to measure changes in the structure and function in the thalamus and WM of patients with MTBI during a short follow-up period, to determine whether these techniques can be used to investigate relationships with cognitive performance and to predict outcome. MATERIALS AND METHODS: Twenty patients with MTBI and 16 controls underwent MR imaging at 3T and a neuropsychological battery designed to yield measures for attention, concentration, executive functioning, memory, learning, and information processing. MK, FA, MD, and CBF were measured in the thalamus by using region-of-interest analysis and in WM by using tract-based spatial statistics. Analyses were performed comparing regional imaging measures of subject groups and the results of testing of their associations with neuropsychological performance. RESULTS: Patients with MTBI exhibited significant differences from controls for DTI, DKI, and ASL measures in the thalamus and various WM regions both within 1 month after injury and >9 months after injury. At baseline, DTI and DKI measures in the thalamus and various WM regions were significantly associated with performance in different neuropsychological domains, and cognitive impairment was significantly associated with MK in the thalamus and FA in optic radiations. CONCLUSIONS: Combined application of DTI, DKI, and ASL to study MTBI might be useful for investigating dynamic changes in the thalamus and WM as well as cognitive impairment during a short follow-up period, though the small number of patients examined did not predict outcome.

Impact of delay after biopsy and post-biopsy haemorrhage on prostate cancer tumour detection using multi-parametric MRI: a multi-reader study.

AIM: To assess impact of haemorrhage and delay after biopsy on prostate tumour detection using multi-parametric (MP) magnetic resonance imaging (MRI) assessment. MATERIALS AND METHODS: Forty-four patients underwent prostate MRI at 1.5 T using a pelvic phased-array coil, including T1-weighted imaging (T1WI), T2-weighted imaging (T2WI), diffusion-weighted imaging (DWI), and dynamic contrast-enhanced (DCE) imaging, before prostatectomy. Three radiologists independently reviewed images during four sessions [T2WI, DWI, DCE, and all parameters combined (MP-MRI)] to assess for tumour in each sextant. In a separate session, readers reviewed T1WI to score the extent of haemorrhage per sextant. Accuracy was assessed using logistic regression for correlated data. RESULTS: There was no significant difference in accuracy between readers for any session (p ≥ 0.166), and results were averaged across the three readers for remaining comparisons. Accuracy was significantly greater for MP-MRI than for any parameter alone (p ≤ 0.020). For T2WI alone, there was a trend toward decreased sensitivity in sextants with extensive haemorrhage (p = 0.072). However, accuracy, sensitivity, and specificity were otherwise similar for sextants with and without extensive haemorrhage for all sessions (p = 0.192-0.934). No session showed a significant improvement in accuracy, sensitivity, or specificity in cases with delay after biopsy of over 4 weeks compared with shorter delay. CONCLUSION: Extensive haemorrhage and short delay after biopsy did not negatively impact accuracy for tumour detection using MP-MRI. Further studies using MP-MRI protocols and interpretation schemes from other institutions are required to confirm these observations.