Comparison of diffusion-weighted images using short inversion time inversion recovery or chemical shift selective pulse as fat suppression in patients with breast cancer

Purpose  Fat suppression is essential for diffusion-weighted imaging (DWI) in the body. However, the chemical shift selective (CHESS) pulse often fails to suppress fat signals in the breast. The purpose of this study was to compare DWI using CHESS and DWI using short inversion time inversion recovery (STIR) in terms of fat suppression and the apparent diffusion coefficient (ADC) value. Materials and methods  DWI using STIR, DWI using CHESS, and contrast-enhanced T1-weighted images were obtained in 32 patients with breast carcinoma. Uniformity of fat suppression, ADC, signal intensity, and visualization of the breast tumors were evaluated. Results  In 44% (14/32) of patients there was insufficient fat suppression in the breasts on DWI using CHESS, whereas 0% was observed on DWI using STIR (P < 0.0001). The ADCs obtained for DWI using STIR were 4.3% lower than those obtained for DWI using CHESS (P < 0.02); there was a strong correlation of the ADC measurement (r = 0.93, P < 0.001). Conclusion  DWI using STIR may be excellent for fat suppression; and the ADC obtained in this sequence was well correlated with that obtained with DWI using CHESS. DWI using STIR may be useful when the fat suppression technique in DWI using CHESS does not work well.     

Clinical application of 3D VIBECAIPI-DIXON for non-enhanced imaging of the pancreas compared to a standard 2D fat-saturated FLASH

PurposeTo compare a fast 3D VIBE sequence with Dixon fat saturation and CAIPIRINHA acceleration techniques (3D VIBE_CAIPI-DIXON) to a standard 2D FLASH sequence with spectral fat saturation and conventional GRAPPA acceleration technique (2D Flash_GRAPPA-fs) for non-enhanced imaging of the pancreas.Methods and materialsIn this retrospective, institutional review board-approved intra-individual comparison study, 29 patients (7 female, 22 male; mean age 60.4±20.9 years) examined on a 48-channel 3.0-T MR system (MAGNETOM Skyra VD 13, Siemens Healthcare Sector, Germany) were included. 3D VIBE_CAIPI-DIXON (TR/TE−3.95/2.5+1.27 ms; spatial resolution−1.2×1.2×3.0 mm³; CAIPIRINHA 2×2 [1], acquisition time−0:12 min) and 2D Flash_GRAPPA-fs (TR/TE−195/3.69 ms; 1.2×1.2×3.0 mm³; GRAPPA 2, 3×0:21 min) sequences were performed in each subject in random order prior to the administration of an intravenous contrast agent. Two radiologists evaluated the images with regard to diagnostic preference. Semi-quantitative signal ratios were calculated for the pancreas versus the liver, spleen, muscle, and visceral fat. Inter-reader agreement was calculated using unweighted Cohen's kappa. Signal ratio results were analyzed using a univariate analysis of variance. Additional signal-to-noise (SNR) measurements were performed in a phantom.Results3D VIBE_CAIPI-DIXON was preferred in 72.4% (both readers) and 2D Flash_GRAPPA-fs in 3.4%/6.9% (reader 1/2) of cases with a kappa value of 0.756. The main reasons for this preference were homogenous fat saturation with 3D VIBE_CAIPI-DIXON and reduced motion artifacts due to a faster acquisition, leading to improved delineation of the pancreas. Signal ratios of pancreatic to fat signal for 3D VIBE_CAIPI-DIXON (10.08±3.48) and 2D Flash_GRAPPA-fs (6.53±3.07) were statistically different (P< .001). However, no additional statistically significant differences in signal ratios were identified (range: 0.73±0.18 to 1.37±0.40; .514 < P< .961). SNR did not statistically significantly differ between the sequences.Conclusion3D VIBE_CAIPI-DIXON enables robust pancreatic imaging with a shorter time and improved fat suppression relative to conventional 2D Flash_GRAPPA-fs. At an acquisition time of 12 seconds, 3D VIBE_CAIPI-DIXON can be obtained in considerably less time than standard fat-saturated VIBE sequences.     

MRI of small intrahepatic mass-forming cholangiocarcinoma and atypical small hepatocellular carcinoma (≤ 3 cm) with cirrhosis and chronic viral hepatitis: a comparative study

ObjectiveThe objective was to identify the decision-making magnetic resonance (MR) features in differentiating small intrahepatic mass-forming cholangiocarcinoma (sIMCC) from atypical small hepatocellular carcinoma (sHCC) (≤ 3 cm) in patients with cirrhosis and chronic viral hepatitis.MethodsSignal features and relative contrast of sHCCs and sIMCCs in T2-weighted and dynamic enhanced imaging were analyzed. A subgroup comparison between the cirrhosis and noncirrhosis chronic viral hepatitis group was also made.ResultsUnivariate analysis revealed that tumor contours (P< .001), signals in T2-weighted (P< .001) and each phase of contrast-enhanced scanning (P< .001), enhancement patterns (P< .001), as well as accompanying findings of tumor capsule (P< .001), hepatic capsule retraction (P< .001), bile duct dilation (P= .031), and transient hepatic intensity difference (P= .002) were different between sIMCC and atypical sHCC. Multivariate analysis indicated that dynamic enhancement patterns (P< .001) and signals in T2-weighted images (P= .024) were independent predictors for differentiation. Confusing MR features were more often observed in the cirrhosis group compared with those in the noncirrhosis chronic viral hepatitis group.ConclusionDynamic enhancement patterns and signals in T2-weighted images were the most important MR features to differentiate sIMCC from atypical sHCC with cirrhosis and chronic viral hepatitis.     

Diffusion-weighted magnetic resonance imaging of head and neck squamous cell carcinomas

ObjectiveTo evaluate whether diffusion-weighted imaging (DWI) is a reliable technique to quantify microstructural differences between head and neck squamous cell carcinomas (SCC) and tumour-free soft tissue.Materials and methodsDWI was obtained from 20 patients with histologically proven, untreated head and neck SCC. DWI was acquired using a diffusion-weighted, navigated echo-planar imaging sequence with a maximum b-value of 800 s/mm². For an objective assessment of image quality, the signal-to-noise ratio (SNR) was calculated. Microstructural differences between vital tumour tissue and tumour-free soft tissue were quantified by calculating the apparent-diffusion-coefficients (ADC) on a pixel by pixel method.ResultsEcho-planar DWI provided good image quality in all patients (mean SNR 18.4). The mean ADC of SCC, (0.64 ± 0.28 × 10⁻³ mm²/s), was significantly (P < 0.0001) lower than that of the tumour-free soft tissue, (2.51 ± 0.82 × 10⁻³ mm²/s).ConclusionDWI is a reliable diagnostic tool to quantify the microstructural differences between vital tumour tissue and tumour-free soft tissue in patients with head and neck SCC.     

Impact of fibroglandular tissue and background parenchymal enhancement on diffusion weighted imaging of breast lesions

PurposeTo evaluate the influence of the amount of fibroglandular breast tissue (FGT) and background-parenchymal enhancement (BPE) on lesion detection, quantitative analysis of normal breast tissue and of breast lesions on DWI.Materials and methodsIRB approved this retrospective study on focal findings at contrast-enhanced (CE) breast MR and DWI performed during July–December 2011. Patients with cysts, previous irradiation, silicone implants and current chemotherapy were excluded. DWI with fat suppression was acquired before dynamic acquisition (b factors: 0.1000 s/mm²) using 1.5 and 3 T scanners. Using correlation with dynamic and T2 images, ROIs were drawn free-hand within the borders of any visible lesion and in contralateral normal breast. Fisher's exact test to evaluate visibility and Wilcoxon-rank-sum test for comparison of ADC values were used. The amount of FGT and BPE was visually assessed by concurrent MRI. Analysis was stratified by menopausal status.Results25/127 (20%) lesions were excluded for technical reasons. 65/102 (64%) lesions were visible on DWI (median diameter: 1.85 cm). Mass lesions (M) were more visible (43/60 = 72%) than non-mass enhancement (NME) (22/42 = 52%) and malignant lesions were more visible (55/72 = 76%) than benign (10/30 = 33%). BPE and FGT did not influence visibility of M (p = 0.35 and p = 0.57 respectively) as well as of NME (p = 0.54 and p = 0.10). BPE and FGT did not influence visibility of malignant (p = 0.96 and p = 1.0) and benign lesions (p = 1.0 and p = 0.10). Results were confirmed adjusting for menopausal status. The ADC value of normal breast tissue was not influenced by BPE, while it was lower in predominantly fatty breasts compared to dense ones (p = 0.002).ConclusionsFGT affects the quantitative evaluation of ADC in normal breast tissue whereas BPE does not. Furthermore, both BPE and FGT do not influence visibility of benign or malignant findings, including both mass lesions and non-mass enhancement, on DWI.     

Uterine fibroids: Influence of “T2-Rim sign” on immediate therapeutic responses to magnetic resonance imaging-guided high-intensity focused ultrasound ablation

ObjectivesTo investigate the influence of a high-signal-intensity peripheral rim on T2-weighted MR images (i.e., T2-rim sign) on the immediate therapeutic responses of MR-guided high intensity focused ultrasound (MR-HIFU) ablation of uterine fibroids.MethodsThis retrospective study was approved by the institutional review board, and patient informed consent was obtained for MR-HIFU ablation. In total, 196 fibroids (diameter 6.2 ± 2.6 cm) in 123 women (age 43.4 ± 5.0 years) who underwent MR-HIFU ablation from January 2013 to April 2016 were included. The effects of a T2-rim sign on the immediate therapeutic responses (non-perfused volume [NPV] ratio, ablation efficiency [NPV/treatment cell volume], ablation quality [grade 1-5, poor to excellent]) were investigated with univariable and multivariable analyses using generalized estimating equation (GEE) analysis. In multivariable analysis, T2 signal intensity ratio of fibroids-to-skeletal muscle, relative peak enhancement of fibroids, and subcutaneous fat thickness were also considered.ResultsThe presence of a T2-rim sign significantly lowered the NPV ratio (54.0 ± 28.0% vs. 83.7 ± 17.7%), ablation efficiency (0.6 ± 0.5 vs. 1.3 ± 0.6), ablation quality (3.1 ± 1.2 vs. 4.2 ± 0.8), (P < 0.0001). GEE analysis showed that the presence of a T2-rim sign was independently significant for ablation efficiency and ablation quality (P < 0.05).ConclusionUterine fibroids with a T2-rim sign showed significantly poorer immediate therapeutic responses to MR-HIFU ablation.     

Correlation between intravoxel incoherent motion MR parameters and MR nodular grade of parotid glands in patients with Sjögren’s syndrome: A pilot study

PurposeTo explore the correlation between intravoxel incoherent motion (IVIM) magnetic resonance (MR) parameters and MR nodular grade of parotid glands in patients with Sjögren’s syndrome (SS).Materials and methodsA total of 31 consecutive patients with SS and 28 gender- and age-matched healthy volunteers underwent bilateral parotid 3.0T MR examination including the IVIM sequence (9 b values, 0–800 s/mm²). The apparent diffusion coefficient (ADC), diffusion coefficient D, pseudo-diffusion coefficient D^*, and perfusion fraction f of bilateral parotid glands were obtained, and the nodular grade of each parotid gland was evaluated according to the MR morphological appearance.ResultsSixty-two parotid glands in 31 patients with SS consisted of 32, 14, 8, and 8 parotid glands at MR nodular grades 0, 1, 2, and 3, respectively. In parotid glands of grade 0, 1, 2, 3 and healthy volunteers, the ADC values were (1.13 ± 0.25, 1.11 ± 0.17, 1.05 ± 0.24, 0.89 ± 0.04 and 1.00 ± 0.21) × 10⁻³ mm²/s, D values were (0.92 ± 0.13, 0.90 ± 0.19, 0.90 ± 0.03, 0.67 ± 0.03, 0.81 ± 0.03) × 10⁻³ mm²/s, f values were 0.20 ± 0.04, 0.18 ± 0.02, 0.15 ± 0.01, 0.11 ± 0.01, 0.15 ± 0.06, and D^*values were (53.89 ± 28.26, 41.78 ± 16.35, 51.24 ± 18.69, 31.83 ± 18.03, 36.83 ± 16.14) × 10⁻³ mm²/s respectively. The ADC, D, f, and D^* values of parotid glands in patients with SS at grade 0 were significantly higher than those in healthy volunteers (all P < 0.05). Significant differences were observed in the D and f values of parotid glands in patients with SS among different grades (P = 0.003, < 0.001, respectively). The IVIM parameters (D, f) of parotid glands at early (grades 0–1) and advanced (grades 2–3) stages in patients with SS were significantly higher and lower, respectively, than those in healthy volunteers (all P < 0.05). The D and f values inversely correlated with MR nodular grades significantly (r = − 0.297, P = 0.019; r = − 0.653, P < 0.001, respectively)ConclusionThe parotid glands with different MR nodular grades in patients with SS showed different IVIM parameters, reflecting different pathophysiological characteristics of parotid glands at different stages.     

Comparison of trans-1-amino-3-[18 F]fluorocyclobutanecarboxylic acid (anti-[18 F]FACBC) accumulation in lymph node prostate cancer metastasis and lymphadenitis in rats

IntroductionTrans-1-amino-3-[¹⁸ F]fluorocyclobutanecarboxylic acid (anti-[¹⁸ F]FACBC) is a positron emission tomography (PET) tracer used to visualize prostate cancer (PCa). In this study, we investigated the differences in anti-[¹⁸ F]FACBC accumulation between metastatic and inflamed lymph node (LN) lesions.MethodsA PCa LN metastasis (PLM) model was developed by inoculating a rat PCa cell line, MAT-Ly-Lu-B2, into popliteal LNs of Copenhagen rats. Acute lymphadenitis (AL) was induced by injecting concanavalin A (Con A) into the hind footpad, and chronic lymphadenitis (CL) was induced by daily injection of Con A into the tissues surrounding the popliteal LNs for 2 weeks. Main lesions of all animal models were established in lumbar and/or inguinal LNs. Biodistribution and dynamic PET imaging data were acquired after tracer injection. T2-weighted magnetic resonance (MR) images were registered with PET images.ResultsIn the biodistribution study, the uptake ratios of PLM-to-lymphadenitis in lesional lumbar and inguinal LNs were 0.97 − 1.57 and 1.47 − 2.08 at 15 and 60 min post-anti-[¹⁸ F]FACBC injection respectively. In PET imaging, the lesional lumbar LNs of CL and PLM, but not of AL, were visualized on anti-[¹⁸ F]FACBC-PET/MR fusion images without disturbance from radioactivity from urine, and the rank order of anti-[¹⁸ F]FACBC accumulation at 50 − 60 post-injection in lesional lumbar LNs was PLM > CL > AL.ConclusionsAnti-[¹⁸ F]FACBC accumulation in LNs with PLM was higher than that in inflamed LNs.Advances in knowledgeThe study showed that although low but significant levels of anti-[¹⁸ F]FACBC uptake by chronic inflamed lesions might cause false-positives in anti-[¹⁸ F]FACBC-PET in some PCa patients, uptake of the tracer at acutely inflamed sites was minimal.Implications for patient careThe findings of this study suggest the potential of Anti-[¹⁸ F]FACBC for distinguishing between tumors and acute inflammation in clinical practice.     

Diagnostic performance of diffusion-weighted MR imaging in differentiation of diabetic osteoarthropathy and osteomyelitis in diabetic foot

PurposeTo study the diagnostic performance of diffusion weighted MR imaging in differentiation of diabetic osteoarthropathy and osteomyelitis in diabetic foot.Patients and methodsThis prospective study was carried out on 41 patients with diabetic foot, 22 males and 19 females with mean age of 51 years. They underwent diffusion-weighted MR imaging of the foot. The apparent diffusion coefficient (ADC) values of the bony lesions were calculated by two reviewers and correlated with the surgical findings or biopsy. The kappa statistic (k) was used to estimate the proportion of inter-observer agreement of two reviewers.ResultsThe mean ADC of acute diabetic osteoarthropathy was 1.27 ± 0.19 × 10⁻³ mm²/s for reviewer 1 and 1.26 ± 0.21 × 10⁻³ mm²/s for reviewer 2. The mean ADC value in diabetic osteomyelitis was 0.86 ± 0.11 × 10⁻³ mm²/s for reviewer 1 and 0.85 ± 0.12 × 10⁻³ mm²/s for reviewer 2. There was excellent inter-observer agreement of ADC value of bony lesions in diabetic foot by both reviewers (K = 0.93). There was statistically significant difference in the ADC values of both groups (P = 0.001). The cut-off point of ADC value of both reviewers used in differentiating acute diabetic osteoarthropathy and osteomyelitis were 0.98 × 10⁻³ mm²/s and 1.04 × 10⁻³ mm²/s with an accuracy of 94% and 93% and area under the curve of 0.94 and 0.93 respectively.ConclusionWe conclude that the ADC value is a non-invasive imaging parameter that can help in differentiation of diabetic osteoarthropathy from osteomyelitis with excellent inter-observer agreement.     

Image quality of ct angiography using model-based iterative reconstruction in infants with congenital heart disease: Comparison with filtered back projection and hybrid iterative reconstruction

PurposeTo compare the image quality, rate of coronary artery visualization and diagnostic accuracy of 256-slice multi-detector computed tomography angiography (CTA) with prospective electrocardiographic (ECG) triggering at a tube voltage of 80 kVp between 3 reconstruction algorithms (filtered back projection (FBP), hybrid iterative reconstruction (iDose⁴) and iterative model reconstruction (IMR)) in infants with congenital heart disease (CHD).MethodsFifty-one infants with CHD who underwent cardiac CTA in our institution between December 2014 and March 2015 were included. The effective radiation doses were calculated. Imaging data were reconstructed using the FBP, iDose⁴ and IMR algorithms. Parameters of objective image quality (noise, signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR)); subjective image quality (overall image quality, image noise and margin sharpness); coronary artery visibility; and diagnostic accuracy for the three algorithms were measured and compared.ResultsThe mean effective radiation dose was 0.61 ± 0.32 mSv. Compared to FBP and iDose⁴, IMR yielded significantly lower noise (P < 0.01), higher SNR and CNR values (P < 0.01), and a greater subjective image quality score (P < 0.01). The total number of coronary segments visualized was significantly higher for both iDose⁴ and IMR than for FBP (P = 0.002 and P = 0.025, respectively), but there was no significant difference in this parameter between iDose⁴ and IMR (P = 0.397). There was no significant difference in the diagnostic accuracy between the FBP, iDose⁴ and IMR algorithms (χ² = 0.343, P = 0.842).ConclusionsFor infants with CHD undergoing cardiac CTA, the IMR reconstruction algorithm provided significantly increased objective and subjective image quality compared with the FBP and iDose⁴ algorithms. However, IMR did not improve the diagnostic accuracy or coronary artery visualization compared with iDose⁴.     

The quantitative diagnostic capability of routine MR imaging and diffusion-weighted imaging in osteoporosis patients

ObjectivesTo determine the quantitative diagnostic capability of magnetic resonance imaging (MRI), compared to dual-energy X-ray absorptiometry (DEXA), for osteoporosis.Materials and MethodsEight male volunteers and eight patients underwent both DEXA and MRI. Results were obtained from each subject's L2 to L4, for a total of 48 lumbar vertebrae. Based on their bone mineral density (BMD) acquired from DEXA, the vertebrae were classified as follows: normal (n= 28), osteopenic (n= 0), and osteoporotic (n= 20). All MR examinations were performed on a 1.5-T scanner to obtain T₁-weighted imaging (T1WI), fat-suppression T₂-weighted imaging (FS-T2WI), and diffusion-weighted imaging (DWI). These quantitative MR parameters were determined: T1WI and FS-T2WI signal-to-noise ratios and DWI apparent diffusion coefficient values. To determine the diagnostic capability of MRI as an osteoporosis indicator, MR parameters were assessed statistically.ResultsAll MR parameters significantly correlated with BMD (T1WI: r=?0.64, FS-T2WI: r=?0.36, DWI: r=?0.29), with significant differences among normal and osteoporotic vertebrae (P< .05). By receiver operating characteristic analysis, the area under the curve of T1WI was significantly higher than others (P< .05). When adapted as feasible threshold values, sensitivity, specificity, and accuracy of T1WI were 95.0% (19/20), 92.9% (26/28), and 93.8% (45/48), respectively.ConclusionRoutine MRI, in particular T1WI, had a potential for the assessment of osteoporosis.     

Dual-energy CT virtual non-calcium technique for detection of bone marrow edema in patients with vertebral fractures: A prospective feasibility study on a single- source volume CT scanner

ObjectivesDual-energy computed tomography (DECT) is a recent development for detecting bone marrow edema (BME) in patients with vertebral compression fractures. The aim of this pilot study was to determine the reliability of single-source DECT in detecting vertebral BME using magnetic resonance imaging (MRI) as standard of reference.Materials and methodsNine patients with radiographic thoracic or lumbar vertebral compression fractures underwent both, DECT on a 320-row single-source scanner and 1.5 T MRI. Virtual non-calcium (VNC) images were reconstructed from the DECT volume datasets. Three blinded readers independently scored images for the presence of BME. Only vertebrae with loss of height in radiography (target vertebrae) were included in the analysis. A vertebra was counted as positive if two readers agreed on the presence of BME. Cohen’s kappa was calculated for interrater comparison. Intervertebral ratios of target and the reference vertebra were compared for CT attenuation and MR signal intensity in a reference vertebra using Spearman correlation. Signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were calculated.ResultsFourteen target vertebrae with a radiographic height loss were identified; eight of them showed BME on MRI, while DECT identified BME in 7 instances. There were no false positive virtual non-calcium images, resulting in a sensitivity of 0.88 (0.75–1.0 among all readers) and specificity of 1.0 (0.81–1.0). Interrater agreement was inferior for DECT (κ = 0.63–0.89) compared to MRI (κ = 0.9–1.0). Intervertebral ratio in VNC images strongly correlated with short-tau inversion recovery (r = 0.87) and inversely with T1 (-0.89). SNR (0.2 +/− 0.2 in VNC and 16.7 +/− 7.3 in STIR) and CNR (0.2 +/− 0.3 and 7.1 +/− 6.3) values were inferior in VNC.ConclusionsDetecting BME with single-source DECT is feasible and allows detection of vertebral compression fractures with reasonably high sensitivity and specificity. However, image quality of VNC reconstructions has to be improved to achieve better interrater agreement. Nonetheless, DECT might accelerate the diagnostic work-flow in patients with vertebral compression fractures in the future and reduce the number of additional MRI examinations.     

The qualitative and quantitative image analysis of MR imaging in patients with acute-on-chronic liver failure

PurposeTo evaluate the distinctive features of ACLF and chronic liver disease (CLD) on MR images using quantitative and qualitative analyses.MethodsTwelve patients with ACLF and 36 patients with CLD who had undergone MR images were included. MR imaging findings from both groups were assessed.ResultsGallbladder edema, esophageal varix, and ascites were significantly more prevalent in the ACLF group (all P-values < 0.05). The liver to muscle SI ratio on T2-WI was significantly higher in the ACLF group (P = 0.002).ConclusionMR imaging findings could be helpful in differentiating between patients with ACLF and those with CLD.     

Dietary supplementation with New Zealand blackcurrant extract enhances fat oxidation during submaximal exercise in the heat

ObjectivesThis study investigated the effect of 7 days’ supplementation with New Zealand blackcurrant extract on thermoregulation and substrate metabolism during running in the heat.DesignRandomized, double-blind, cross-over study.MethodsTwelve men and six women (mean ± SD: Age 27 ± 6 years, height 1.76 ± 0.10 m, mass 74 ± 12 kg, V̇O_2max 53.4 ± 7.0 mL kg⁻¹ min⁻¹) completed one assessment of maximal aerobic capacity and one familiarisation trial (18 °C, 40% relative humidity, RH), before ingesting 2 × 300 mg day⁻¹ capsules of CurraNZ™ (each containing 105 mg anthocyanin) or a visually matched placebo (2 × 300 mg microcrystalline cellulose M102) for 7 days (washout 14 days). On day 7 of each supplementation period, participants completed 60 min of fasted running at 65% V̇O_2max in hot ambient conditions (34 °C and 40% relative humidity).ResultsCarbohydrate oxidation was decreased in the NZBC trial [by 0.24 g min⁻¹ (95% CI: 0.21–0.27 g min^-1)] compared to placebo (p =  0.014, d = 0.46), and fat oxidation was increased in the NZBC trial [by 0.12 g min⁻¹ (95% CI: 0.10 to 0.15 g min⁻¹)], compared to placebo (p = 0.008, d = 0.57). NZBC did not influence heart rate (p = 0.963), rectal temperature (p = 0.380), skin temperature (p = 0.955), body temperature (p = 0.214) or physiological strain index (p = 0.705) during exercise.ConclusionsSeven-days intake of 600 mg NZBC extract increased fat oxidation without influencing cardiorespiratory or thermoregulatory variables during prolonged moderate intensity running in hot conditions.     

Improved clinical workflow for simultaneous whole-body PET/MRI using high-resolution CAIPIRINHA-accelerated MR-based attenuation correction

PurposeTo explore the value and reproducibility of a novel magnetic resonance based attenuation correction (MRAC) using a CAIPIRINHA-accelerated T1-weighted Dixon 3D-VIBE sequence for whole-body PET/MRI compared to the clinical standard.MethodsThe PET raw data of 19 patients from clinical routine were reconstructed with standard MRAC (MRAC_std) and the novel MRAC (MRAC_caipi), a prototype CAIPIRINHA accelerated Dixon 3D-VIBE sequence, both acquired in 19 s/bed position. Volume of interests (VOIs) for liver, lung and all voxels of the total image stack were created to calculate standardized uptake values (SUV_mean) followed by inter-method agreement (Passing-Bablok regression, Bland-Altman analysis). A voxel-wise SUV comparison per patient was performed for intra-individual correlation between MRAC_std and MRAC_caipi. Difference images (MRAC_std-MRAC_caipi) of attenuation maps and SUV images were calculated. The image quality of in/opposed-phase water and fat images obtained from MRAC_caipi was assessed by two readers on a 5-point Likert-scale including intra-class coefficients for inter-reader agreement.ResultsSUV_mean correlations of VOIs demonstrated high linearity (0.95 < Spearman’s rho < 1, p < 0.0001, respectively), substantiated by voxel-wise SUV scatter-plots (1.79 × 10⁸ pixels). Outliers could be explained by different physiological conditions between the scans such as different segmentation of air-containing tissue, lungs, kidneys, metal implants, diaphragm edge or small air bubbles in the gastrointestinal tracts that moved between MRAC acquisitions. Nasal sinuses and the trachea were better segmented in MRAC_caipi. High-resolution T1w Dixon 3D VIBE images were acquired in all cases and could be used for PET/MRI fusion. MRAC_caipi images were of high diagnostic quality (4.2 ± 0.8) with 0.92-0.96 intra-class correlation.ConclusionsThe novel prototype MRAC_caipi extends the value for attenuation correction by providing a high spatial resolution DIXON-based dataset suited for diagnostic assessment towards time-efficient whole-body PET/MRI.     

Evaluation of sclerosis in Modic changes of the spine using susceptibility-weighted magnetic resonance imaging

PurposeTo evaluate the diagnostic performance of susceptibility-weighted magnetic resonance imaging (SWMR) for the differentiation of sclerotic and non-sclerotic Modic changes (MC) of the spine compared to computed tomography (CT) and radiographs.Materials and methodsThe Institutional Ethics-Review-Board approved this prospective study in advance. Written consent was obtained from all subjects. SWMR and standard T1/T2 MR of the cervical (n = 21) and/or lumbar spine (n = 34) were performed in 54 patients. 21 patients served as control. 18 patients were evaluated with CT; in all other patients radiographs were available. 67 Modic changes were identified on T1/T2 MR. On SWMR changes were classified as sclerotic and non-sclerotic based on signal intensity measurements. The sensitivity and specificity of SWMR and T1/T2 MR for differentiating between sclerotic and non-sclerotic Modic changes were determined with CT and radiographs as reference standard.ResultsOn SWMR, signal measurements between sclerotic and non-sclerotic Modic changes differed significantly (p < 0.01). On T1- and T2-weighted MR no significant difference (p > 0.05) was measured. On SWMR, a reliable differentiation between sclerotic and non-sclerotic Modic changes could be achieved, with a sensitivity of 100% and specificity of 95%. In contrast, the combination of T1-/T2-weighted MR yielded a significantly lower sensitivity to detect sclerosis (20%).ConclusionSWMR allows a reliable detection of sclerosis in Modic changes with a higher accuracy compared to standard spine MR sequences, using radiographs and CT as reference standard.     

Comparison of photoinactivation of T. rubrum by new methylene blue (NMB) and indocyanine green (EmunDo®)

BackgroundSuperficial mycotic skin infections which are predominantly caused by Trichophyton rubrum, poorly responsd to conventional therapies. A great amount of attention has focused on finding more effective treatments. The current work is aimed to compare the effectiveness of phoinactivation of Trichophyton rubrum by two relatively new photosensitizers: a phenothiazinium dye(New methylene blue) and Indocyanine green (EmunDo^®).Materials and methodsA Final inoculum of T. rubrum which corresponded to 10⁶ colony forming unit per milliliter (CFU ml⁻¹) was prepared. Antimicrobial Photodynamic treatment (aPDT) of T. rubrum was carried out by either EmunDo^® (1 mg/ml, Infra-red laser (IRL, λ = 810 nm, Energy Density 55 J/cm²)) or NMB (10 μM, Red laser (RL), λ = 630 nm, Energy Density of 5 J/cm²). The suspensions thereafter were subcultured on Sabouraud dextrose agar (SDA) and were counted on due time. based on colony-forming unit per milliliter (CFU/ml).ResultsaPDT with either EmunDo^® (E) or NMB (N) considerably diminished the viability of inoculated T. rubrum with respective reduction of 0.64 log and 0.4 log compared to the control group (P < 0.001). No significant difference was found between two laser only groups (P = 0.79) and two aPDT groups (P = 0.73), however significant reduction of T. rubrum in red laser only group (P = 0.04) and EmunDo^® only group (P = 0.04) was found as compared to the control group (P < 0.05).ConclusionThe study provides evidence regarding satisfactory photodynamic inactivation of T. rubrum with EmunDo^® or NMB as photosensitizers. Irradiation by only red laser source was found superior to only infra-red laser source. Dark toxicity of EmunDo^® was more successful than new methylene blue dye.     

Unusually high prostate-specific antigen bounce after prostate brachytherapy: Searching for etiologic factors

PurposeDetermine whether fat distribution, body mass index, or clinical and dosimetric factors are associated with prostate specific antigen (PSA) bounce (PSAb) of ≥1.6 ng/mL in patients treated with permanent seed ¹²⁵I prostate brachytherapy (PB).Methods and MaterialsWe identified 23 patients with a PSAb of ≥1.6 ng/mL. For each patient with a bounce, at least one control with similar age (age ± 2 years, n = 31) was identified. Control patients had to have no bounce (≤0.2 ng/mL) and a most recent PSA of <1 ng/mL. CT at Day 30 after PB was used to determine the volume of subcutaneous adipose tissue, visceral adipose tissue, and peri-prostatic fat. Univariate and multivariate logistic models were used to assess the association between PSAb and adipose tissue distribution and clinical and dosimetric factors.ResultsMean patient age was 62.3 ± 5.3 years. Mean PSAb height was 2.7 ± 0.8 ng/mL, and mean time to bounce was 9.6 ± 4 months. More than 90% of the patients reached a PSA nadir before PSAb within 12 months post-PB. Patients showing PSAb were more likely to have a T1c disease vs. T2a (odds ratio = 18.87; 95% confidence interval: 2.32–454.55; p = 0.019) and a lower seed activity per cc of prostate volume (odds ratio = 0.02; 95% confidence interval = 0.42–2.22; p = 0.026). Neither fat distribution nor body mass index was associated with PSAb (p = 0.11–0.597).ConclusionsClinical and dosimetric factors play a role in PSAb of ≥1.6 ng/mL. Fat distribution is not associated with a PSAb. There is presently no satisfactory theory to explain the etiology of PSAb.     

Whole-body 18F-FDG PET/CT for M staging in the patient with newly diagnosed nasopharyngeal carcinoma: Who needs?

ObjectiveAlthough whole-body fluorine-18 fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography (PET)/computed tomography (CT) (¹⁸F-FDG PET/CT) is commonly used for M staging of newly diagnosed nasopharyngeal carcinoma (NPC), some patients may not benefit from this procedure. The present study investigated which patients require this modality for M staging.MethodsWhole-body ¹⁸F FDG PET/CT results and clinical data were collected for 264 patients with newly diagnosed NPC. The relationships between distant metastasis and age, gender, pathological type, lesion size, SUVmax-T, T staging, N staging, SUVmax-N and Epstein-Barr virus (EBV) quantity were retrospectively analysed to identify factors associated with increased risk.ResultsOf the 264 patients, only 37 (14.0%) were diagnosed with distant metastasis. Using multiple logistic regression analysis, EBV-positivity (OR = 13.1; 95% CI:1.61,106.80), N staging (OR = 3.05; 95% CI:1.41,6.63) and T staging (OR = 2.16; 95% CI:1.10, 4.24) were significantly related to distant metastasis (all P < 0.05). EBV DNA levels ≥ 9000 copies/ml, N3 stage and T4 stage were identified as high risk factors. A low risk of distant metastasis was found in patients with 0–1 risk factors and in those with 2 specific risk factors, T3/T4 and N2/N3 staging. Patients with EBV DNA levels ≥9000 copies/ml and N3 or T4 staging and those with 3 risk factors had a medium or high risk, with a much higher incidence of distant metastasis (χ² = 29.896, P = 0.000), and needed a whole-body ¹⁸F FDG PET/CT for M staging.ConclusionsDue to the low incidence of distant metastasis, only patients with medium or high risk need to undergo a whole-body scan.     

Malignant breast tumours: Correlation of apparent diffusion coefficient values using diffusion-weighted images and dynamic contrast-enhancement ratio with histologic grading

PurposeTo evaluate the correlation of the apparent diffusion coefficient (ADC) using diffusion weighted imaging (DWI) and early/delayed enhancement (E/D) ratio using dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) with histological grading in malignant breast lesions.Material and methodsThirty-one women with 34 histopathologically proved malignant breast lesions underwent MRI within 2 weeks prior to surgery. MRI examination included T1 and T2 W sequences, DWI and DCE-MRI. ADC values and E/D ratios are correlated with the histological grades.ResultsThe mean ADC of the malignant lesions was 0.85 ± 0.12 × 10^?3 mm²/s. The mean ADC values of grade I, II and III were 0.96 ± 0.12 × 10^?3 mm²/s, 0.87 ± 0.07 × 10^?3 mm²/s and 0.75 ± 0.12 × 10^?3 mm²/s, respectively. Tumours with higher grade showed significantly lower ADC value (p = 0.0001) compared with lower grade and there is an inverse correlation between ADC value and histological grade (r = ?0.62, p-value = 0.0001). The mean E/D ratio for grade I, II and III tumours were 0.98 ± 0.04, 1.01 ± 0.05 and 1.07 ± 0.08, respectively. Tumours with higher grade showed significantly higher E/D ratio (p = 0.005) compared with lower grade and there was a direct correlation between E/D ratio and histological grade (r = 0.44, p = 0.008).ConclusionDWI is a useful diagnostic parameter with significantly higher correlation with the histological grade of breast cancer than DCE MRI, which is an important factor for proper treatment selection.