Lifestyle Score and Risk of Hypertension in the Airwave Health Monitoring Study of British Police Force Employees.

BACKGROUND: Evidence suggest that promoting a combination of healthy lifestyle behaviors instead of exclusively focusing on a single behavior may have a greater impact on blood pressure (BP). We aimed to evaluate lifestyle factors and their impact on the risk of hypertension and BP. METHODS: We analyzed cross-sectional health-screening data from the Airwave Health Monitoring Study of 40,462 British police force staff. A basic lifestyle-score including waist-circumference, smoking and serum total cholesterol was calculated, with a greater value indicating a better lifestyle. Individual/combined scores of other lifestyle factors (sleep duration, physical activity, alcohol intake, and diet quality) were also developed. RESULTS: A 1-point higher basic lifestyle-score was associated with a lower systolic BP (SBP; -2.05 mmHg, 95%CI: -2.15, -1.95); diastolic BP (DBP; -1.98 mmHg, 95%CI: -2.05, -1.91) and was inversely associated with risk of hypertension. Combined scores of other factors showed attenuated but significant associations with the addition of sleep, physical activity, and diet quality to the basic lifestyle-score; however, alcohol intake did not further attenuate results. CONCLUSIONS: Modifiable intermediary factors have a stronger contribution to BP, namely, waist-circumference and cholesterol levels and factors that may directly influence them, such as diet, physical activity and sleep. Observed findings suggest that alcohol is a confounder in the BP-lifestyle score relation.

Trends and Inequalities in the Incidence of Acute Myocardial Infarction among Beijing Townships, 2007-2018.

Acute myocardial infarction (AMI) poses a serious disease burden in China, but studies on small-area characteristics of AMI incidence are lacking. We therefore examined temporal trends and geographic variations in AMI incidence at the township level in Beijing. In this cross-sectional analysis, 259,830 AMI events during 2007-2018 from the Beijing Cardiovascular Disease Surveillance System were included. We estimated AMI incidence for 307 consistent townships during consecutive 3-year periods with a Bayesian spatial model. From 2007 to 2018, the median AMI incidence in townships increased from 216.3 to 231.6 per 100,000, with a greater relative increase in young and middle-aged males (35-49 years: 54.2%; 50-64 years: 33.2%). The most pronounced increases in the relative inequalities was observed among young residents (2.1 to 2.8 for males and 2.8 to 3.4 for females). Townships with high rates and larger relative increases were primarily located in Beijing's northeastern and southwestern peri-urban areas. However, large increases among young and middle-aged males were observed throughout peri-urban areas. AMI incidence and their changes over time varied substantially at the township level in Beijing, especially among young adults. Targeted mitigation strategies are required for high-risk populations and areas to reduce health disparities across Beijing.

Quantifying Diet Intake and Its Association with Cardiometabolic Risk in the UK Airwave Health Monitoring Study: A Data-Driven Approach.

We used data-driven approaches to identify independent diet exposures among 45 candidate variables, for which we then probed cross-sectional associations with cardiometabolic risk (CMR). We derived average daily caloric intake and macronutrient composition, daily meal frequencies, and irregularity of energy and macronutrient intake from 7-day food diaries in the Airwave Health Monitoring Study participants (N = 8090). We used K-means and hierarchical clustering to identify non-redundant diet exposures with representative exposures for each cluster chosen by silhouette value. We then used multi-variable adjusted logistic regression to estimate prevalence ratios (PR) and 95% confidence intervals (95%CI) for CMR (≥3 criteria: dyslipidemia, hypertension, central adiposity, inflammation and impaired glucose control) across diet exposure quartiles. We identified four clusters: i) fat intake, ii) carbohydrate intake, iii) protein intake and intake regularity, and iv) meal frequencies and energy intake. Of these clusters, higher carbohydrate intake was associated with lower likelihood of CMR (PR = 0.89, 95%CI = 0.81-0.98; ptrend = 0.02), as was higher fiber intake (PR = 0.76, 95%CI = 0.68-0.85; ptrend < 0.001). Higher meal frequency was also associated with lower likelihood of CMR (PR = 0.76, 95%CI = 0.68-0.85; ptrend < 0.001). Our results highlight a novel, data-driven approach to select non-redundant, minimally collinear, primary exposures across a host of potentially relevant exposures (including diet composition, temporal distribution, and regularity), as often encountered in nutritional epidemiology.

Diffusion Kurtosis Imaging in the Assessment of Cervical Carcinoma.

RATIONALE AND OBJECTIVES: To evaluate the additional value of diffusion kurtosis imaging (DKI) in the characterization of cervical carcinoma. MATERIALS AND METHODS: Seventy-five patients (56.9 ± 13.4 years) with histologic-confirmed cervical carcinoma were included. Diffusion-weighted imaging (DWI) was acquired on a 3T MRI with five b values (0, 500, 800, 1000, and 1500 s/mm2). Data were analyzed based on DKI model (5 b values) and conventional DWI (0 and 1000 s/mm2). Largest single-slice region of interest (ROI) and volume of interest (VOI) were drawn around the tumor. Mean diffusivity (MD), mean kurtosis (MK), and apparent diffusion coefficient (ADC) of cervical carcinoma and normal myometrium were measured and compared. MD, MK, and ADC of cervical carcinoma were compared among histologic subtypes, tumor grades, and FIGO stages. RESULTS: ROI- and VOI-derived DKI parameters and ADC were all in excellent consistency (intraclass correlation coefficient, ICC > 0.90, respectively). Cervical carcinoma had significantly lower MD, ADC, and higher MK than normal myometrium (p < 0.001). MD and ADC showed significant differences between histologic subtypes and FIGO stages, lower in squamous cell carcinoma than adenocarcinoma and higher in FIGO I-II than FIGO III-IV (p < 0.050), but not with tumor grade. No difference was observed in MK for different clinicopathologic features tested. CONCLUSION: ROI and VOI analyses were in excellent consistency. MD and ADC were able to distinguish histologic subtypes and separating FIGO stages, MK could not. DKI showed no clear added value over conventional DWI in the characterization of cervical carcinoma.

Gene-diet quality interactions on haemoglobin A1c and type 2 diabetes risk: The Airwave Health Monitoring Study.

INTRODUCTION: Type 2 diabetes (T2D) is multifactorial involving lifestyle, environmental and genetic risk factors. This study aims to investigate the impact of genetic interactions with alcohol and diet quality on glycated haemoglobin A1c (HbA1c) independent of obesity, in a British population. METHODS: Cross-sectional study of 14 089 white British participants from Airwave Health Monitoring Study and a subsample of 3733 participants with dietary data. A T2D genetic risk score (GRS) was constructed, and its interactions with diet on HbA1c were assessed. RESULTS: GRS was associated with a higher HbA1c% (ß = 0.03, P < 0.0001) and a higher risk of prediabetes (OR = 1.09, P < 0.0001) and T2D (OR = 1.14, P = 0.006). The genetic effect on HbA1c% was significantly higher in obese participants (ß = 1.88, P interaction = 0.03). A high intake of wholegrain attenuated the effect on HbA1c% in high-risk individuals P interaction = 0.04. CONCLUSION: The genetic effect on HbA1c was almost doubled in obese individuals, compared with those with a healthy weight, and independent of weight, there was a modest offset on HbA1c in high-genetic-risk individuals consuming a diet high in wholegrain. This supports the importance of a healthy diet high in wholegrains and along with maintaining a healthy weight in controlling HbA1c among high-genetic-risk groups.

Intakes and Food Sources of Dietary Fibre and Their Associations with Measures of Body Composition and Inflammation in UK Adults: Cross-Sectional Analysis of the Airwave Health Monitoring Study.

The purpose of this study was to investigate the associations between intakes of fibre from the main food sources of fibre in the UK diet with body mass index (BMI), percentage body fat (%BF), waist circumference (WC) and C-reactive protein (CRP). Participants enrolled in the Airwave Health Monitoring Study (2007-2012) with 7-day food records (n = 6898; 61% men) were included for cross-sectional analyses. General linear models evaluated associations across fifths of fibre intakes (total, vegetable, fruit, potato, whole grain and non-whole grain cereal) with BMI, %BF, WC and CRP. Fully adjusted analyses showed inverse linear trends across fifths of total fibre and fibre from fruit with all outcome measures (ptrend < 0.0001). Vegetable fibre intake showed an inverse association with WC (ptrend 0.0156) and CRP (ptrend 0.0005). Fibre from whole grain sources showed an inverse association with BMI (ptrend 0.0002), %BF (ptrend 0.0007) and WC (ptrend 0.0004). Non-whole grain cereal fibre showed an inverse association with BMI (Ptrend 0.0095). Direct associations observed between potato fibre intake and measures of body composition and inflammation were attenuated in fully adjusted analyses controlling for fried potato intake. Higher fibre intake has a beneficial association on body composition, however, there are differential associations based on the food source.

Integrating dynamic contrast-enhanced magnetic resonance imaging and diffusion kurtosis imaging for neoadjuvant chemotherapy assessment of nasopharyngeal carcinoma.

BACKGROUND: Since neoadjuvant chemotherapy (NAC) has proven a benefit for locally advanced nasopharyngeal carcinoma (NPC), early response evaluation after chemotherapy is important to implement individualized therapy for NPC in the era of precision medicine. PURPOSE: To determine the combined and independent contribution between dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and diffusion kurtosis imaging (DKI) in the early monitoring of NAC response for NPC. STUDY TYPE: Prospective. POPULATION: Fifty-three locally advanced NPC patients. FIELD STRENGTH/SEQUENCE: Four examinations before and at 4, 20, and 40 days after NAC initiation were performed at 3T MRI including DCE-MRI and DKI (b values = 0, 500, 1000, 1500 s/mm2 ). ASSESSMENT: DCE-MRI parameters (Ktrans [the volume transfer constant of Gd-DTPA], kep [rate constant], νe [the extracellular volume fraction of the imaged tissue], and νp [the blood volume fraction]) and DKI parameters (Dapp [apparent diffusion for non-Gaussian distribution] and Kapp [apparent kurtosis coefficient]) were analyzed using dedicated software. STATISTICAL TESTS: MRI parameters and their corresponding changes were compared between responders and nonresponders after one or two NAC cycles treatment using independent-samples Student's t-test or Mann-Whitney U-test depending on the normality contribution test and then followed by logistic regression and receiver operating characteristic curve (ROC) analyses. RESULTS: The responder group (RG) patients presented significantly higher mean Ktrans and Dapp values at baseline and larger Δ K ( 0 - 4 ) trans , Δvp(0-4) , and ΔDapp(0-4) values after either one or two NAC cycles compared with the nonresponder group (NRG) patients (all P < 0.05). ROC analyses demonstrated the higher diagnostic accuracy of combined DCE-MRI and DKI model to distinguish nonresponders from responders after two NAC cycles than using DCE-MRI (0.987 vs. 0.872, P = 0.033) or DKI (0.987 vs. 0.898, P = 0.047) alone. DATA CONCLUSION: Combined DCE-MRI and DKI models had higher diagnostic accuracy for NAC assessment compared with either model used independently. LEVEL OF EVIDENCE: 2 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2018;47:1208-1216.

Nutrient profiling and adherence to components of the UK national dietary guidelines association with metabolic risk factors for CVD and diabetes: Airwave Health Monitoring Study.

CVD is the leading cause of death worldwide. Diet is a key modifiable component in the development of CVD. No official UK diet quality index exists for use in UK nutritional epidemiological studies. The aims of this study are to: (i) develop a diet quality index based on components of UK dietary reference values (DRV) and (ii) determine the association between the index, the existing UK nutrient profile (NP) model and a comprehensive range of cardiometabolic risk markers among a British adult population. A cross-sectional analysis was conducted using data from the Airwave Health Monitoring Study (n 5848). Dietary intake was measured by 7-d food diary and metabolic risk using waist circumference, BMI, blood lipid profile, glycated Hb (HbA1c) and blood pressure measurements. Diet quality was assessed using the novel DRV index and NP model. Associations between diet and cardiometabolic risk were analysed via multivariate linear models and logistic regression. A two-point increase in NP score was associated with total cholesterol (ß -0·33 mmol/l, P<0·0001) and HbA1c (ß -0·01 %, P<0·0001). A two-point increase in DRV score was associated with waist circumference (ß -0·56 cm, P<0·0001), BMI (ß -0·15 kg/m2, P<0·0001), total cholesterol (ß -0·06 mmol/l, P<0·0001) and HbA1c (ß -0·02 %, P=0·002). A one-point increase in DRV score was associated with type 2 diabetes (T2D) (OR 0·94, P=0·01) and obesity (OR 0·95, P<0·0001). The DRV index is associated with overall diet quality and risk factors for CVD and T2D, supporting its application in nutritional epidemiological studies investigating CVD risk in a UK population.

Quantitative assessment of liver function with whole-liver T1rho mapping at 3.0T.

OBJECTIVES: To assess the segmental liver function in healthy subjects and liver cirrhosis (LC) patients with different Child-Pugh grades using whole-liver T1rho mapping at 3.0T. METHODS: Thirty-three healthy volunteers and 33 patients with clinically diagnosed LC were examined using a three-dimensional (3D) whole-liver coverage T1rho mapping. T1rho maps were calculated from five respiratory-triggered sequences with different spin-lock durations (0, 10, 20, 40, and 60ms). The patients were classified into group A with Child-Pugh A cirrhosis and group B with Child-Pugh B or C cirrhosis. The hepatic T1rho values in different segments of the healthy volunteers and LC patients were compared, and receiver operating characteristic curves (ROC) were plotted to determine the performance of T1rho. RESULTS: The median T1rho value of the patients (Child-Pugh class A: 47.07ms; Child-Pugh classes B and C: 51.09ms) was significantly higher than that of the healthy volunteers (39.37ms, P<0.001). No remarkable variations among different hepatic segments in LC patients with various Child-Pugh grades were found (P>0.05). The T1rho values of the liver parenchyma were significantly correlated with albumin (r=-0.590, P<0.001) and prothrombin time (r=0.601, P<0.001). The T1rho values in patients increased with an increase in the Child-Pugh classification (r=0.574, P<0.001). CONCLUSIONS: The whole-liver coverage T1rho sequence at 3.0T was feasible for the assessment of segmental liver function. T1rho relaxation might be a potential biomarker for the estimation of liver function in LC patients.

A cross-sectional investigation into the occupational and socio-demographic characteristics of British police force employees reporting a dietary pattern associated with cardiometabolic risk: findings from the Airwave Health Monitoring Study.

PURPOSE: The aims of this study were to (1) determine the association between diet quality using the Dietary Approaches to Stop Hypertension (DASH) score and cardiometabolic risk in a British working population and (2) identify employee characteristics associated with reporting a poorer quality dietary pattern. METHODS: British police employees enrolled (2007-2012) into the Airwave Health Monitoring Study (n = 5527) were included for sex-specific cross-sectional analyses. Dietary intakes were measured using 7-day food records. DASH score was calculated to determine diet quality. Logistic regression evaluated associations between (1) diet quality and increased cardiometabolic risk (defined as ≥ 3 risk markers: dyslipidaemia, elevated blood pressure, waist circumference, CRP or HbA1c), and (2) poor diet quality (lowest fifth of DASH score distribution) and employee characteristics. RESULTS: Employees recording a poor diet quality had greater odds (OR) of increased cardiometabolic risk independent of established risk factors (demographic, lifestyle and occupational) and BMI: men OR 1.50 (95% CI 1.12-2.00), women: OR 1.84 (95% CI 1.19-2.97) compared to the healthiest diet group. Characteristics associated with reporting a poor quality diet were employment in Scotland vs. England: men OR 1.88 (95% CI 1.53-2.32), women: OR 1.49 (95% CI 1.11-2.00), longer working hours (≥ 49 vs. ≤40 h) men: OR 1.53 (95% CI 1.21-1.92) women: OR 1.53 (95% CI 1.12-2.09). For men, job strain (high vs. low) was associated with reporting a poor diet quality OR 1.66 (95% CI 1.30-2.12). CONCLUSIONS: The general population disparities in diet quality between England and Scotland were reflected in British police employees. The association of longer working hours and job strain with diet quality supports the targeting of workplace nutritional interventions.

Dietary assessment of British police force employees: a description of diet record coding procedures and cross-sectional evaluation of dietary energy intake reporting (The Airwave Health Monitoring Study).

OBJECTIVES: Dietary intake is a key aspect of occupational health. To capture the characteristics of dietary behaviour that is affected by occupational environment that may affect disease risk, a collection of prospective multiday dietary records is required. The aims of this paper are to: (1) collect multiday dietary data in the Airwave Health Monitoring Study, (2) describe the dietary coding procedures applied and (3) investigate the plausibility of dietary reporting in this occupational cohort. DESIGN: A dietary coding protocol for this large-scale study was developed to minimise coding error rate. Participants (n 4412) who completed 7-day food records were included for cross-sectional analyses. Energy intake (EI) misreporting was estimated using the Goldberg method. Multivariate logistic regression models were applied to determine participant characteristics associated with EI misreporting. SETTING: British police force employees enrolled (2007-2012) into the Airwave Health Monitoring Study. RESULTS: The mean code error rate per food diary was 3.7% (SD 3.2%). The strongest predictors of EI under-reporting were body mass index (BMI) and physical activity. Compared with participants with BMI<25 kg/m2, those with BMI>30 kg/m2 had increased odds of being classified as under-reporting EI (men OR 5.20 95% CI 3.92 to 6.89; women OR 2.66 95% CI 1.85 to 3.83). Men and women in the highest physical activity category compared with the lowest were also more likely to be classified as under-reporting (men OR 3.33 95% CI 2.46 to 4.50; women OR 4.34 95% CI 2.91 to 6.55). CONCLUSIONS: A reproducible dietary record coding procedure has been developed to minimise coding error in complex 7-day diet diaries. The prevalence of EI under-reporting is comparable with existing national UK cohorts and, in agreement with previous studies, classification of under-reporting was biased towards specific subgroups of participants.

Intravoxel incoherent motion MRI assessment of chemoradiation-induced pelvic bone marrow changes in cervical cancer and correlation with hematological toxicity.

PURPOSE: To investigate bone marrow changes after chemoradiation (CRT) using intravoxel incoherent motion magnetic resonance imaging (IVIM-MRI) and correlate imaging changes with hematological toxicity (HT) in patients with locally advanced cervical cancer. MATERIALS AND METHODS: Thirty-nine patients with newly diagnosed cervical cancer were prospectively recruited for two sequential 3.0T IVIM-MRI studies: before treatment (MRI-1) and 3-4 weeks after standardized CRT (MRI-2). The irradiated pelvic bone marrow was outlined as the regions of interest to derive the true diffusion coefficient (D) and perfusion fraction (f) based on a biexponential model. The apparent coefficient diffusion (ADC) was derived using the monoexponential model. Changes in these parameters between MRI-1 and MRI-2 were calculated as ΔD, Δf, and ΔADC. HT was defined accordingly to NCI-CTCAE (v. 4.03) of grade 3 and above. Statistical analysis was performed using Mann-Whitney U-test. RESULTS: The median age of patients was 54 years old (range 27-83 years old); 14 patients suffered from HT. Early bone marrow changes (3-4 weeks) of ΔD showed a significant difference between HT and non-HT groups (6.4 ± 19.7% vs. -6.4 ± 19.4%, respectively, P = 0.041). However, no significant changes were noted in Δf (3.7 ± 13.3% vs. 1.5 ± 12.5% respectively, P = 0. 592) and ΔADC (5.5 ± 26.3% vs. -3.3 ± 27.0% respectively, P = 0.303) between the HT and non-HT groups. Δf increased insignificantly for both groups. CONCLUSION: ΔD was the only significant parameter to differentiate early cellular environment changes in bone marrow after CRT, suggestive that ΔD was more sensitive than Δf and ΔADC to reflect the underlying microenvironment injury. LEVEL OF EVIDENCE: 2 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2017;46:1491-1498.

Assessment of tibial and common peroneal nerves in diabetic peripheral neuropathy by diffusion tensor imaging: a case control study.

OBJECTIVES: To determine the diagnostic accuracy and interobserver performance of diffusion tensor imaging (DTI) in diabetic peripheral neuropathy (DPN) and detect correlations with electrophysiology. METHODS: Twelve healthy volunteers (controls) and ten DPN patients were enrolled to undergo MR examinations. Fractional anisotropy (FA) and apparent diffusion coefficient (ADC) values of tibial nerve (TN) and common peroneal nerve (CPN) were measured. Unpaired t test and Levene tests were performed to assess differences between the two groups. Receiver operating characteristic (ROC) analysis was performed for FA and ADC values. Pearson correlation coefficient was used to assess the correlation between DTI and electrophysiology parameters in the patient group. RESULTS: The FA values of TN and CPN in the DPN group were significantly lower and ADC were higher than the control group (p < 0.05). Interobserver agreement was excellent. FA positively correlated and ADC negatively correlated with motor nerve conduction velocity (MCV) (p < 0.05). There were no significant differences between motor nerve conduction amplitude and DTI parameters (p > 0.05). Moderate diagnostic accuracy of DTI was seen in the diagnosis of DPN. CONCLUSIONS: DTI demonstrates moderate diagnostic accuracy and excellent interobserver performance in the detection of DPN involving the TN and CPN. There is moderate correlation with MCV. KEY POINTS: • FA values of TN and CPN are significantly lower in DPN. • ADC values of TN and CPN are significantly higher in DPN. • DTI demonstrates moderate diagnostic accuracy in detection of DPN. • There is excellent interobserver performance in DTI measurements. • Moderate correlation is seen between DTI parameters and MCV.

Early responses assessment of neoadjuvant chemotherapy in nasopharyngeal carcinoma by serial dynamic contrast-enhanced MR imaging.

PURPOSE: To evaluate the feasibility of utilizing serial dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) prospectively for early prediction of neoadjuvant chemotherapy (NAC) response in nasopharyngeal carcinoma (NPC) patients. MATERIALS AND METHODS: Sixty-three advanced NPC patients were recruited and received three DCE-MRI exams before treatment (Pre-Tx), 3days (Day3-Tx) and 20days (Day20-Tx) after initiation of chemotherapy (one NAC cycle). Early response to NAC was determined based on the third MRI scan and classified partial response (PR) as responders and stable disease (SD) as non-responders. After intensity-modulated radiotherapy (IMRT), complete response (CR) patients were classified as responders. The kinetic parameters (Ktrans, Kep, ve, and vp) derived from extended Tofts' model analysis and their corresponding changes ΔMetrics(0-X) (X=3 or 20days) were compared between the responders and non-responders using the Student's T-test or Mann-Whitney U test. RESULTS: Compared to the SD group, the PR group after one NAC cycle presented significantly higher mean Ktrans values at baseline (P=0.011) and larger ΔKtrans(0-3) and ΔKep(0-3) values (P=0.003 and 0.031). For the above parameters, we gained acceptable sensitivity (range: 66.8-75.0%) and specificity (range: 60.0-66.7%) to distinguish the non-responders from the responders and their corresponding diagnosis efficacy (range: 0.703-0.767). The PR group patients after one NAC cycle showed persistent inhibition of tumor perfusion by NAC as explored by DCE-MRI parameters comparing to the SD group (P<0.05) and presented a higher cure ratio after IMRT than those who did not (83.3% vs. 73.8%). CONCLUSIONS: This primarily DCE-MRI based study showed that the early changes of the kinetic parameters during therapy were potential imaging markers to predicting response right after one NAC cycle for NPC patients.

Use of intravoxel incoherent motion diffusion-weighted MR imaging for assessment of treatment response to invasive fungal infection in the lung.

OBJECTIVES: The purpose of this study was to determine whether intravoxel incoherent motion (IVIM) -derived parameters and apparent diffusion coefficient (ADC) could act as imaging biomarkers for predicting antifungal treatment response. METHODS: Forty-six consecutive patients (mean age, 33.9 ± 13.0 y) with newly diagnosed invasive fungal infection (IFI) in the lung according to EORTC/MSG criteria were prospectively enrolled. All patients underwent diffusion-weighted magnetic resonance (MR) imaging at 3.0 T using 11 b values (0-1000 sec/mm2). ADC, pseudodiffusion coffiecient D*, perfusion fraction f, and the diffusion coefficient D were compared between patients with favourable (n=32) and unfavourable response (n=14). RESULTS: f values were significantly lower in the unfavourable response group (12.6%±4.4%) than in the favourable response group (30.2%±8.6%) (Z=4.989, P<0.001). However, the ADC, D, and D* were not significantly different between the two groups (P>0.05). Receiver operating characteristic curve analyses showed f to be a significant predictor for differentiation, with a sensitivity of 93.8% and a specificity of 92.9%. CONCLUSIONS: IVIM-MRI is potentially useful in the prediction of antifungal treatment response to patients with IFI in the lung. Our results indicate that a low perfusion fraction f may be a noninvasive imaging biomarker for unfavourable response. KEY POINTS: • Recognition of IFI indicating clinical outcome is important for treatment decision-making. • IVIM can reflect diffusion and perfusion information of IFI lesions separately. • Perfusion characteristics of IFI lesions could help differentiate treatment response. • An initial low f may predict unfavourable response in IFI.

Assessment of liver fibrosis in rats by MRI with apparent diffusion coefficient and T1 relaxation time in the rotating frame.

PURPOSE: To explore the value of T1 relaxation times in the rotating frame (T1 ρ or T1 rho) for evaluating liver fibrosis stage, compared to apparent diffusion coefficients (ADCs). MATERIALS AND METHODS: Liver fibrosis in model rats (n = 50) was produced by carbon tetrachloride (CCl4 ) injection. Five rats died during the experiment. Surviving model rats (n = 45) and controls (n = 15) were subjected to 3.0T MRI and the ADCs (b-values: 0, 800 s/mm(2) ) and T1 ρ values were determined. Liver fibrosis stage (F0-F4) was defined based on METAVIR scoring. Nonparametric statistical methods and receiver operating characteristic (ROC) curve analyses were employed to determine diagnostic accuracy. RESULTS: Mean ADC and T1 ρ associated negatively (r = -0.732 P < 0.001) and positively (r = 0.863 P < 0.001), respectively, with severity of fibrosis stage. Analysis of ROC curves for fibrosis staging showed that the area under the curve (AUC) for T1 ρ (stage F0 vs. F1-F4 = 0.976, stage F0-F1 vs. F2-F4 = 0.920, stage F0-F2 vs. F3-F4 = 0.938, and stage F0-F3 vs. F4 = 0.931) was larger than that for ADCs (0.917, 0.924, 0.842, and 0.781, respectively). CONCLUSION: ADC and T1 ρ values correlate with liver fibrosis stage. The performance of the T1 ρ parameter was superior to that of the ADC parameter in the differentiation of liver fibrosis stages in a CCl4 rat model.

MRI assessment of excess cardiac iron in thalassemia major: When to initiate?

BACKGROUND: To determine optimal initial age of cardiac iron screening with magnetic resonance imaging (MRI) T2* in patients with thalassemia major (TM). METHODS: We retrospectively reviewed black blood cardiac T2* assessments from 102 TM patients from the ages of 3 to 32 years. Cases of patients under and above 7 years old with detectable cardiac iron overload were analyzed separately. Associations between cardiac T2* and various factors, such as serum ferritin (SF), patient age and hepatic T2*, were assessed using either scatterplots or regression. Images were evaluated by two independent radiologists. RESULTS: With a T2* cut-off value of 20 ms, no patient under 5 years old showed cardiac iron overload. Three of 19 (15.8%) patients under 7 years of age had a cardiac T2* ≤ 20 ms (5.5 to 7 years) but none had ≤10 ms, while 35 of 83 (42.2%) patients above 7 years old had a cardiac T2* ≤ 20 ms (8 to 32 years) and 18 of them ≤10 ms. Cardiac T2* correlated weakly with serum ferritin and liver T2* (r = -0.39 and 0.41, respectively, both P < 0.001), but not with patient age (P > 0.05). CONCLUSION: Cardiac iron overload can occur in young TM patients, even as young as 5.5 years old. Assessment of cardiac iron with T2* might need to begin as early as 5 years old if suboptimal chelation therapy is administered.

Quantification of T(1ρ) relaxation by using rotary echo spin-lock pulses in the presence of B(0) inhomogeneity.

T(1ρ) relaxation is traditionally described as a mono-exponential signal decay with spin-lock time. However, T(1ρ) quantification by fitting to the mono-exponential model can be substantially compromised in the presence of field inhomogeneities, especially for low spin-lock frequencies. The normal approach to address this issue involves the development of dedicated composite spin-lock pulses for artifact reduction while still using the mono-exponential model for T(1ρ) fitting. In this work, we propose an alternative approach for improved T(1ρ) quantification with the widely-used rotary echo spin-lock pulses in the presence of B(0) inhomogeneities by fitting to a modified theoretical model which is derived to reveal the dependence of T(1ρ)-prepared magnetization on T(1ρ), T(2ρ), spin-lock time, spin-lock frequency and off-resonance, without involving complicated spin-lock pulse design. It has potentials for T(1ρ) quantification improvement at low spin-lock frequencies. Improved T(1ρ) mapping was demonstrated on phantom and in vivo rat spin-lock imaging at 3 T compared to the mapping using the mono-exponential model.

Quantitative assessment of cerebral hemodynamic parameters by QUASAR arterial spin labeling in Alzheimer's disease and cognitively normal Elderly adults at 3-tesla.

QUASAR arterial spin labeling (ASL) was used to investigate the role of vascular impairment in Alzheimer's disease (AD). We hypothesized that the hemodynamic parameters monitoring cerebrovascular integrity, i.e., cerebral blood flow (CBF), arterial blood volume (aBV), and arterial transit time (aTT), would be affected. 13 AD patients and 15 healthy control (HC) subjects underwent 3T MRI scanning. Two separate blood flow acquisitions were obtained with 1 slice overlap for whole brain coverage. CBF, aBV, and aTT maps were calculated using in-house software. Preprocessing and statistical analyses were performed on SPM5. Region-of-interest (ROI) studies of ten selected cerebral regions were also conducted. There were significant differences in mini mental status exam (MMSE) (AD: 16.3 ± 4.55, HC: 28.5 ± 2.00) and Alzheimer's disease assessment scale-cognitive subscale (ADAS-cog) scores (AD: 25.25 ± 9.64, HC: 5.51 ± 2.62) between the 2 groups (p < 0.001) but none in age (p = 0.068). CBF decreased significantly (p < 0.01) in AD compared to controls in the right middle cingulate, left cuneus, left inferior and middle frontal, right superior frontal, left inferior parietal, and right supramarginal gyri. ROI studies confirmed significant hemodynamic impairments in AD compared to HC (p < 0.05): CBF in middle and posterior cingulate, aBV in left superior temporal, right inferior parietal, and posterior cingulate, and aTT in left inferior frontal and middle cingulate gyri. CBF correlated positively while aTT correlated negatively to MMSE, and vice versa for ADAS-cog. Using QUASAR ASL, we found patterns of regional hemodynamic impairment typical of moderate AD, suggesting underlying vascular abnormality. As potential biomarkers, these hemodynamic parameters could differentiate patients from volunteers, and possibly indicate the conversion from healthy aging to mild cognitive impairment to AD.

Optimized efficient liver T(1ρ) mapping using limited spin lock times.

T(1ρ) relaxation has recently been found to be sensitive to liver fibrosis and has potential to be used for early detection of liver fibrosis and grading. Liver T(1ρ) imaging and accurate mapping are challenging because of the long scan time, respiration motion and high specific absorption rate. Reduction and optimization of spin lock times (TSLs) are an efficient way to reduce scan time and radiofrequency energy deposition of T(1ρ) imaging, but maintain the near-optimal precision of T(1ρ) mapping. This work analyzes the precision in T(1ρ) estimation with limited, in particular two, spin lock times, and explores the feasibility of using two specific operator-selected TSLs for efficient and accurate liver T(1ρ) mapping. Two optimized TSLs were derived by theoretical analysis and numerical simulations first, and tested experimentally by in vivo rat liver T(1ρ) imaging at 3 T. The simulation showed that the TSLs of 1 and 50 ms gave optimal T(1ρ) estimation in a range of 10-100 ms. In the experiment, no significant statistical difference was found between the T(1ρ) maps generated using the optimized two-TSL combination and the maps generated using the six TSLs of [1, 10, 20, 30, 40, 50] ms according to one-way ANOVA analysis (p = 0.1364 for liver and p = 0.8708 for muscle).