Digital differentiation of non-small cell carcinomas of the lung by the fractal dimension of their epithelial architecture

IntroductionIn recent years, differences have emerged in the treatment of squamous and non-squamous non-small cell lung carcinomas (NSCLCs). This highlights the importance of accurate histopathologic classification. However, there remains inter-observer disagreement when making diagnoses based on histology. Fractal dimension (FD) is a mathematical measure of irregularity and complexity of shape. We hypothesize that the FD of carcinoma epithelial architecture can assist in differentiating adenocarcinoma (ADC) from squamous cell carcinoma (SCC) of the lung.Methods134 resected (88 ADC and 46 SCC) cases of resected early-stage NSCLC were analyzed. Tissue micro arrays were generated from formalin-fixed paraffin-embedded tissue, stained with pan-cytokeratin, and digitally imaged and the FD of the epithelial structure calculated. Mean FD of ADC and SCC were compared using the independent t-test, partial correlations, and receiver operating characteristic (ROC) analyses.ResultsA statistically significant difference (p < 0.001) between the mean FD of ADC (M = 1.70, SD = 0.07) and SCC (M = 1.78, SD = 0.07) was found. Significance remained (p < 0.001) when controlling for several possible confounders. ROC analysis demonstrated an area-under-the-curve of 0.81 (p < 0.001).ConclusionsThe epithelial structure FD of NSCLC has potential as a reproducible and automated measure to help subtype NSCLCs into ADC and SCC. With further image analysis algorithm improvements, fractal analysis may be a component in computerized histomorphological assessments of lung cancer and may provide an adjunct test in differentiating NSCLCs.     

Predicting the nodal status in gastric cancers: The role of apparent diffusion coefficient histogram characteristic analysis

PurposeTo explore the application of histogram analysis in preoperative T and N staging of gastric cancers, with a focus on characteristic parameters of apparent diffusion coefficient (ADC) maps.Materials and methodsEighty-seven patients with gastric cancers underwent diffusion weighted magnetic resonance imaging (b = 0, 1000 s/mm²), which generated ADC maps. Whole-volume histogram analysis was performed on ADC maps and 7 characteristic parameters were obtained. All those patients underwent surgery and postoperative pathologic T and N stages were determined.ResultsFour parameters, including skew, kurtosis, s-sD_av and sample number, showed significant differences among gastric cancers at different T and N stages. Most parameters correlated with T and N stages significantly and worked in differentiating gastric cancers at different T or N stages. Especially skew yielded a sensitivity of 0.758, a specificity of 0.810, and an area under the curve (AUC) of 0.802 for differentiating gastric cancers with and without lymph node metastasis (P < 0.001). All the parameters, except AUC_low, showed good or excellent inter-observer agreement with intra-class correlation coefficients ranging from 0.710 to 0.991.ConclusionCharacteristic parameters derived from whole-volume ADC histogram analysis could help assessing preoperative T and N stages of gastric cancers.     

Enhanced Laws textures: A potential MRI surrogate marker of hepatic fibrosis in a murine model

PurposeTo compare enhanced Laws textures derived from parametric proton density (PD) maps to other MRI surrogate markers (T₂, PD, apparent diffusion coefficient (ADC)) in assessing degrees of liver fibrosis in an ex vivo murine model of hepatic fibrosis imaged using 11.7T MRI.MethodsThis animal study was IACUC approved. Fourteen male, C57BL/6 mice were divided into control and experimental groups. The latter were fed a 3,5-dicarbethoxy-1,4-dihydrocollidine (DDC) supplemented diet to induce hepatic fibrosis. Ex vivo liver specimens were imaged using an 11.7T scanner, from which the parametric PD, T₂, and ADC maps were generated from spin-echo pulsed field gradient and multi-echo spin-echo acquisitions. A sequential enhanced Laws texture analysis was applied to the PD maps: automated dual-clustering algorithm, optimal thresholding algorithm, global grayscale correction, and Laws texture features extraction. Degrees of fibrosis were independently assessed by digital image analysis (a.k.a. %Area Fibrosis). Scatterplot graphs comparing enhanced Laws texture features, T₂, PD, and ADC values to degrees of fibrosis were generated and correlation coefficients were calculated.ResultsHepatic fibrosis and the enhanced Laws texture features were strongly correlated with higher %Area Fibrosis associated with higher Laws textures (r = 0.89). Without the proposed enhancements, only a moderate correlation was detected between %Area Fibrosis and unenhanced Laws texture features (r = 0.70). Correlation also existed between %Area Fibrosis and ADC (r = 0.86), PD (r = 0.65), and T₂ (r = 0.66).ConclusionsHigher degrees of hepatic fibrosis are associated with increased Laws textures. The proposed enhancements could improve the accuracy of Laws texture features significantly.     

Differentiation of central gland prostate cancer from benign prostatic hyperplasia using monoexponential and biexponential diffusion-weighted imaging

PurposeTo investigate biexponential apparent diffusion parameters of prostate central gland (CG) cancer, stromal hyperplasia (SH), and glandular hyperplasia (GH) and compare with monoexponential apparent diffusion coefficient (ADC) value for discriminating prostate cancer from benign hyperplasia.Materials and MethodsTwenty-one CG cancer foci, 23 SH and 26 GH nodules in the CG were analyzed in 39 patients (19 with CG cancer, 20 with peripheral zone cancer but no CG cancer) who underwent preoperative conventional DWI (b-value 0, 1000 s/mm²) and a 10 b-value (range 0 to 3000 s/mm²) DWI. All of the cancer and hyperplastic foci on MR images were localized on the basis of histopathologic correlation. The ADC value of the monoexponential DWI, and the fast apparent diffusion coefficient (ADCf), slow apparent diffusion coefficient (ADCs) value and the fraction of ADCf (f) of the biexponential DWI were calculated for all of the lesions. Receiver operating characteristic (ROC) analysis was performed for the differentiation of CG cancer from SH and GH.ResultsThe ADC values (× 10^? 3 mm²/s) were 0.87 ± 0.11, 1.06 ± 0.15, and 1.61 ± 0.27 in CG cancer, SH and GH foci, respectively, and differed significantly, yielding areas under the ROC curve (AUCs) of 1.00 and 0.80 for the differentiation of carcinoma from GH and SH, respectively. The ADCf (× 10^? 3 mm²/s), ADCs (× 10^? 3 mm²/s) and f for cancer were 1.92 ± 0.38, 0.53 ± 0.17, and 47.7 ± 6.1%, respectively, which were lower than the same values for GH (3.43 ± 0.65, 1.12 ± 0.21, 61.1 ± 8.7%) (all p < 0.01). The ADCf and ADCs for cancer were also lower than those for SH (3.11 ± 0.30, 0.79 ± 0.21) (all p < 0.01). The ADCf yielded AUCs (1.00, p > 0.01) that were comparable to those from ADC for the differentiation of cancer from GH, while ADCf yielded higher AUCs (0.92) compared with ADC (p < 0.01) for the differentiation of cancer from SH. ADCs and f revealed AUCs of 0.97 and 0.90, respectively, for the differentiation of cancer from GH, and the ADCs offered relatively lower AUCs (0.68) for differentiating cancer from SH.ConclusionBiexponential DWI could potentially improve the differentiation of prostate cancer in CG, and the ADCf of the biexponential model offers better accuracy than ADC.     

The study of the intervertebral disc microstructure in matured rats with diffusion kurtosis imaging

ObjectivesThe aim of this study was to use DKI to detect the microstructural change of the discs in matured normal rats.MethodsTotal 24 normal SD rats (12 males/12 females) underwent DWI/DKI and T2 sequences with a 3T MRI scanner to get the values of ADC, FA, MD, Da, Dr, MK, Ka and Kr. The discs were categorized using a five-grade degeneration grading system in the T2-images. The height of the discs and the parameters in DWI/DKI were measured to compare between the different grades and sexes. The histological images and the images of fiber tracking were also done in the discs.ResultsThere were 30 Grade 1 and 18 Grade 2 in the discs. Compared with Grade 1, decreased ADC, increased FA and MK values were observed in Grade 2 (P < 0.05). By the ROC analysis of grades of the discs, there was low diagnostic accuracy in ADC value, while FA and MK showed higher accuracy. In Grade 1, there were lower ADC value, lower Dr, higher MK, Ka and Kr in male's group than them in female's group. There were no differences in the parameters except the ADC value in the two sexes in Grade 2. The different microstructure of the normal discs in the male and female rats had been proved by the histological images and the images of fiber tracking.ConclusionDKI is a noninvasive and sustainable means to test the changes of intervertebral discs. The discs in Grade 2 were also found in the normal matured SD rat tails. The assessment of the grade of the discs in T2-images should be done before the experimental management. There was microstructural difference in the nucleus pulposus in the discs in Grade 1 and 2. FA and MK showed higher diagnostic accuracy. The laboratory rats should be the same sex because the microstructure of the normal discs weren't the same.     

The effect of morphological and microstructural integrity of the corpus callosum on cognition,fatigue and depression in mildly disabled MS patients

AimTo assess the value of callosal morphological and microstructural integrity in assessing different cognitive domains, fatigue and depression in mildly disabled multiple sclerosis (MS) patients.Materials and methodsWe assessed 29 mildly disabled MS patients and 15 healthy controls using 3T magnetic resonance images (T1-weighted, FLAIR and DTI) and neuropsychological tests assessing different cognitive functions, depression and fatigue. We compared the added value of morphological measures (corpus callosum area corrected for total intracranial volume, index, circularity and the more detailed thickness profile) and diffusion features (fractional anisotropy and mean diffusivity) in multilinear models including standard clinical and whole-brain parameters in assessing neuropsychological scores.ResultsEven in mildly disabled MS patients, a significant reduction of the corpus callosum (p < 0.001) was observed in comparison to healthy controls. Callosal area, index and circularity were significantly (p < 0.002) related to whole-brain white matter volume, T2 lesion load and deep grey matter volume, but not with cortical grey matter.The combination of commonly used imaging and clinical parameters explained between 7% (Fatigue) and 50% (processing speed, verbal memory) of the adjusted variance. Inclusion of the mean diffusivity increased the adjusted R² significantly to 69% (p = 0.004) and 71% (p = 0.002) for visuospatial and verbal memory respectively.ConclusionOur results show that callosal features may be used as an alternative to measuring whole-brain volumes. Furthermore, the microstructural integrity of the corpus callosum can help to predict an MS patient's memory performance.     

Assessment of the link between quantitative biexponential diffusion-weighted imaging and contrast-enhanced MRI in the liver

PurposeTo investigate if intravoxel incoherent motion (IVIM) modeled diffusion-weighted imaging (DWI) can be linked to contrast-enhanced (CE-)MRI in liver parenchyma and liver lesions.MethodsTwenty-five patients underwent IVIM-DWI followed by multiphase CE-MRI using Gd-EOB-DTPA (n = 20) or Gd-DOTA (n = 5) concluded with IVIM-DWI. Diffusion (D_slow), microperfusion (D_fast), its fraction (f_fast), wash-in-rate (R_early) and late-enhancement-rate (R_late) of Gd-EOB-DTPA were calculated voxel-wise for the liver. Parenchyma and lesions were segmented. Pre-contrast IVIM was compared 1) between low, medium and high R_early for parenchyma 2) to post-contrast IVIM substantiated with simulations 3) between low and high R_late per lesion type.ResultsD_fast and f_fast increased (P < 0.001) with 25.6% and 33.8% between low and high R_early of Gd-EOB-DTPA. D_slow decreased (− 15.0%; P < 0.001) with increasing R_early. Gd-DOTA demonstrated similar observations. f_fast (+ 10%; P < 0.001) and D_fast (+ 6.6%; P < 0.001) increased after Gd-EOB-DTPA, while decreasing after Gd-DOTA (− 4.2% and − 5.7%, P < 0.001) and were confirmed by simulations. For focal nodular hyperplasia lesions (n = 5) D_fast and f_fast increased (P < 0.001) with increasing R_late, whereas for hepatocellular carcinoma (n = 4) and adenoma (n = 7) no differences were found.ConclusionMicroperfusion measured by IVIM reflects perfusion in a way resembling CE-MRI. Also IVIM separated intra- and extracellular MR contrast media. This underlines the potential of IVIM in quantitative liver imaging.     

Pre-operative assessment of residual disease in locally advanced breast cancer patients: A sequential study by quantitative diffusion weighted MRI as a function of therapy

PurposeThe potential of diffusion weighted imaging (DWI) in assessing pathologic response and surgical margins in locally advanced breast cancer patients (n = 38) undergoing neoadjuvant chemotherapy was investigated.MethodsDWI was performed at pre-therapy (Tp0), after I (Tp1) and III (Tp3) NACT at 1.5 T. Apparent diffusion coefficient (ADC) of whole tumor (ADC_WT), solid tumor (ADC_ST), intra-tumoral necrosis (ADC_Nec) was determined. Further, ADC of 6 consecutive shells (5 mm thickness each) including tumor margin to outside tumor margins (OM1 to OM5) was calculated and the data analyzed to define surgical margins.ResultsOf 38 patients, 6 were pathological complete responders (pCR), 19 partial responders (pPR) and 13 were non-responders (pNR). Significant increase was observed in ADC_ST and ADC_WT in pCR and pPR following therapy. Pre-therapy ADC was significantly lower in pCR compared to pPR and pNR indicating the heterogeneous nature of tumor which may affect drug perfusion and consequently the response. ADC of outside margins (OM1, OM2, and OM3) was significantly different among pCR, pPR and pNR at Tp3 which may serve as response predictive parameter. Further, at Tp3, ADC of outside margins (OM1, OM2, and OM3) was significantly lower compared to that seen at Tp0 in pCR, indicating the presence of residual disease in these shells.ConclusionPre-surgery information may serve as a guide to define cancer free margins and the extent of residual disease which may be useful in planning breast conservation surgery.     

Abnormal lipid metabolism in skeletal muscle tissue of patients with muscular dystrophy: In vitro,high-resolution NMR spectroscopy based observation in early phase of the disease

PurposeQualitative (assignment of lipid components) and quantitative (quantification of lipid components) analysis of lipid components were performed in skeletal muscle tissue of patients with muscular dystrophy in early phase of the disease as compared to control/normal subjects.MethodsProton nuclear magnetic resonance (NMR) spectroscopy based experiment was performed on the lipid extract of skeletal muscle tissue of patients with muscular dystrophy in early phase of the disease and normal individuals for the analysis of lipid components [triglycerides, phospholipids, total cholesterol and unsaturated fatty acids (arachidonic, linolenic and linoleic acid)]. Specimens of muscle tissue were obtained from patients with Duchenne muscular dystrophy (DMD) [n = 11; Age, Mean ± SD; 9.2 ± 1.4 years; all were males], Becker muscular dystrophy (BMD) [n = 12; Age, Mean ± SD; 21.4 ± 5.0 years; all were males], facioscapulohumeral muscular dystrophy (FSHD) [n = 11; Age, Mean ± SD; 23.7 ± 7.5 years; all were males] and limb girdle muscular dystrophy-2B (LGMD-2B) [n = 18; Age, Mean ± SD; 24.2 ± 4.1 years; all were males]. Muscle specimens were also obtained from [n = 30; Mean age ± SD 23.1 ± 6.0 years; all were males] normal/control subjects.ResultsAssigned lipid components in skeletal muscle tissue were triglycerides (TG), phospholipids (PL), total cholesterol (CHOL) and unsaturated fatty acids (arachidonic, linolenic and linoleic acid)]. Quantity of lipid components was observed in skeletal muscle tissue of DMD, BMD, FSHD and LGMD-2B patients as compared to control/normal subjects. TG was significantly elevated in muscle tissue of DMD, BMD and LGMD-2B patients. Increase level of CHOL was found only in muscle of DMD patients. Level of PL was found insignificant for DMD, BMD and LGMD-2B patients. Quantity of TG, PL and CHOL was unaltered in the muscle of patients with FSHD as compared to control/normal subjects. Linoleic acids were significantly reduced in muscle tissue of DMD, BMD, FSHD and LGMD-2B as compared to normal/control individuals.ConclusionsResults clearly indicate alteration of lipid metabolism in patients with muscular dystrophy in early phase of the disease. Moreover, further evaluation is required to understand whether these changes are primary or secondary to muscular dystrophy. In future, these findings may prove an additional and improved approach for the diagnosis of different forms of muscular dystrophy.     

4D cardiac imaging at clinical 3.0 T provides accurate assessment of murine myocardial function and viability

ObjectivesWe validate a 4D strategy tailored for 3 T clinical systems to simultaneously quantify function and infarct size in wild type mice after ischemia/reperfusion, with improved spatial and temporal resolution by comparison to previous published protocols using clinical field MRI systems.MethodsC57BL/6J mice underwent 60 min ischemia/reperfusion (n = 14) or were controls without surgery (n = 6). Twenty-four hours after surgery mice were imaged with gadolinium injection and sacrificed for post-mortem MRI and histology with serum also taken for Troponin I levels. The double ECG- and respiratory-triggered 3D FLASH (Fast Low Angle Shot) gradient echo (GRE) cine sequence had an acquired isotropic resolution of 344 μm, TR/TE of 7.8/2.9 ms and acquisition time 25–35 min. The conventional 2D FLASH cine sequence had the same in-plane resolution of 344 μm, 1 mm slice thickness and TR/TE 11/5.4 ms for an acquisition time of 20–25 min plus 5 min for planning. Left ventricle (LV) and right ventricle (RV) volumes were measured and functional parameters compared 2D to 3D, left to right and for inter and intra observer reproducibility. MRI infarct volume was compared to histology.ResultsFor the function evaluation, the 3D cine outperformed 2D cine for spatial and temporal resolution. Protocol time for the two methods was equivalent (25–35 min). Flow artifacts were reduced (p = 0.008) and epi/endo-cardial delineation showed good intra and interobserver reproducibility. Paired t-test comparing ejection volume left to right showed no significant difference for 3D (p = 0.37), nor 2D (p = 0.30) and correlation slopes of left to right EV were 1.17 (R² = 0.75) for 2D and 1.05 (R² = 0.50) for 3D.Quantifiable ‘late gadolinium enhancement’ infarct volume was seen only with the 3D cine and correlated to histology (R² = 0.89). Left ejection fraction and MRI-measured infarct volume correlated (R² > 0.3).ConclusionsThe 4D strategy, with contrast injection, was validated in mice for function and infarct quantification from a single scan with minimal slice planning.     

A non-contrast CMR index for assessing myocardial fibrosis

PurposeSafe, sensitive, and non-invasive imaging methods to assess the presence, extent, and turnover of myocardial fibrosis are needed for early stratification of risk in patients who might develop heart failure after myocardial infarction. We describe a non-contrast cardiac magnetic resonance (CMR) approach for sensitive detection of myocardial fibrosis using a canine model of myocardial infarction and reperfusion.MethodsSeven dogs had coronary thrombotic occlusion of the left anterior descending coronary arteries followed by fibrinolytic reperfusion. CMR studies were performed at 7 days after reperfusion. A CMR spin-locking T₁ρ mapping sequence was used to acquire T₁ρ dispersion data with spin-lock frequencies of 0 and 511 Hz. A fibrosis index map was derived on a pixel-by-pixel basis. CMR native T₁ mapping, first-pass myocardial perfusion imaging, and post-contrast late gadolinium enhancement imaging were also performed for assessing myocardial ischemia and fibrosis. Hearts were dissected after CMR for histopathological staining and two myocardial tissue segments from the septal regions of adjacent left ventricular slices were qualitatively assessed to grade the extent of myocardial fibrosis.ResultsHistopathology of 14 myocardial tissue segments from septal regions was graded as grade 1 (fibrosis area, < 20% of a low power field, n = 9), grade 2 (fibrosis area, 20–50% of field, n = 4), or grade 3 (fibrosis area, > 50% of field, n = 1). A dramatic difference in fibrosis index (183%, P < 0.001) was observed by CMR from grade 1 to 2, whereas differences were much smaller for T₁ρ (9%, P = 0.14), native T₁ (5.5%, P = 0.12), and perfusion (− 21%, P = 0.05).ConclusionA non-contrast CMR index based on T₁ρ dispersion contrast was shown in preliminary studies to detect and correlate with the extent of myocardial fibrosis identified histopathologically. A non-contrast approach may have important implications for managing cardiac patients with heart failure, particularly in the presence of impaired renal function.     

Assessment of the patellofemoral cartilage: Correlation of knee pain score with magnetic resonance cartilage grading and magnetization transfer ratio asymmetry of glycosaminoglycan chemical exchange saturation transfer

PurposeBiochemical imaging of glycosaminoglycan chemical exchange saturation transfer (gagCEST) could predict the depletion of glycosaminoglycans (GAG) in early osteoarthritis. The purpose of this study was to evaluate the relationship between the magnetization transfer ratio asymmetry (MTR_asym) of gagCEST images and visual analog scale (VAS) pain scores in the knee joint.Materials and methodsThis retrospective study was approved by the institutional review board. A phantom study was performed using hyaluronic acid to validate the MTR_asym values of gagCEST images. Knee magnetic resonance (MR) images of 22 patients (male, 9; female, 13; mean age, 50.3 years; age range; 25–79 years) with knee pain were included in this study. The MR imaging (MRI) protocol involved standard knee MRI as well as gagCEST imaging, which allowed region-of-interest analyses of the patellar facet and femoral trochlea. The MTR_asym at 1.0 ppm was calculated at each region. The cartilages of the patellar facets and femoral trochlea were graded according to the Outerbridge classification system. Data regarding the VAS scores of knee pain were collected from the electronic medical records of the patients. Statistical analysis was performed using Spearman's correlation.ResultsThe results of the phantom study revealed excellent correlation between the MTR_asym values and the concentration of GAGs (r = 0.961; p = 0.003). The cartilage grades on the MR images showed significant negative correlation with the MTR_asym values in the patellar facet and femoral trochlea (r = −0.460; p = 0.031 and r = −0.543; p = 0.009, respectively). The VAS pain scores showed significant negative correlation with the MTR_asym values in the patellar facet and femoral trochlea (r = −0.435; p = 0.043 and r = −0.671; p = 0.001, respectively).ConclusionThe pain scores were associated with the morphological and biochemical changes in articular cartilages visualized on knee MR images. The biochemical changes, visualized in terms of the MTR_asym values of the gagCEST images, exhibited greater correlation with the pain scores than the morphological changes visualized on conventional MR images; these results provide evidence supporting the theory regarding the association of patellofemoral osteoarthritis with knee pain scores.     

Photoionization studies of the atmospherically important species N and OH at the Elettra synchrotron radiation source

In this paper angularly resolved photoelectron spectra (PES) and constant-ionic-state (CIS) spectra are presented for the atmospherically important species N and OH.The natural width Γ, line shape parameters q and ρ² and discrete oscillator strengths f have been measured for the members of the N*[2s2p³(⁵S), np] (⁴P) ← N(⁴S) autoionizing resonances for n = 5–10. The n = 5 parameters calculated in this work are in good agreement with the values obtained previously whereas for the resonances with n = 6–10 the values of these parameters are reported for the first time. The asymmetry parameter (β) for the first band of N atoms, the N⁺(³P) ← N(⁴S) ionization, has also been measured in the photon energy range of the above autoionizing resonances.For OH, CIS spectra have been recorded for the first photoelectron band corresponding to the ionization OH⁺(X³Σ⁻, v⁺ = 0) ← OH(X²Π, v″ = 0). In these spectra, rotationally partially resolved bands associated with OH*(a¹Δ3d, v′ = 0) ← OH(X²Π, v″ = 0) resonances have been observed. Suggestions for their assignment are made on the basis of their positions and band simulations which use rotational line strength calculations.     

Comparison of breath-hold,respiratory navigated and free-breathing MR elastography of the liver

PurposeHepatic magnetic resonance elastography (MRE) is currently a breath-hold imaging technique. Patients with chronic liver disease can have comorbidities that limit their ability to breath-hold (BH) for the required acquisition time. Our aim was to evaluate whether stiffness measurements obtained from a navigator-triggered MRE acquisition are comparable to standard expiratory breath-hold, inspiratory breath-hold or free-breathing in healthy participants.Materials and methodsTwelve healthy participants were imaged using the four methods on a clinical 1.5 T MR system equipped with a product MRE system. Mean liver stiffness, and measurable area of stiffness (with a confidence threshold >95%) were compared between sequences using the concordance correlation coefficient. Repeatability of each sequence between two acquisitions was also assessed.ResultsThe standard BH expiratory technique had high concordance with the navigated technique (r = 0.716), and low concordance with the BH inspiration (r = 0.165) and free-breathing (r = 0.105) techniques. The navigator-triggered technique showed no statistical difference in measurable area of liver or in repeatability compared with the standard expiratory acquisition (p = 0.997 and p = 0.407 respectively). The free-breathing technique produced less measurable liver area and was less repeatable than the alternative techniques. The increase in acquisition time for navigator techniques was 3 min 6 s compared to standard expiratory breath-hold.ConclusionNavigator-based hepatic MRE measurements are comparable to the reference standard expiratory breath-hold acquisition in healthy participants.     

Perfusion of the uterine junctional zone in nulliparous and primiparous women assessed by DCE-MRI,as a function of menstrual cycle and hormonal contraception

PurposeTo evaluate the perfusion parameters of inner and outer myometrium in healthy nulliparous and primiparous women who are and who are not currently using hormonal contraceptives by means of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI).Material and methodsWe performed pelvic 1.5 T DCE-MRI on 98 women: 18 nulliparous non-users, 30 nulliparous users, 12 primiparous non-users and 38 primiparous users of hormonal contraception (mean age respectively 26.4, 25.8, 30.23 and 28.18 years). The nulliparous non-users underwent DCE-MRI investigations during their follicular, ovulatory and luteal phase. Perfusion parameters (iAUC/volume, Ktrans, Kep and Ve) were assessed in the anterior and posterior junctional zone (JZ), outer myometrium and cervix.ResultsIn nulliparous non-users, the mean Ktrans and iAUC/volume showed a decrease from follicular to luteal phase (0.82 vs 0.55 min^− 1 for Ktrans, p = 0/027 and 1.28 vs 0.68 for iAUC/volume, p < 0.001). The anterior JZ demonstrated lower Ktrans (p = 0.050) and higher Kep (p = 0.012), in nulliparous non-users, lower Ktrans in nulliparous users (p < 0.001) and lower Ve in primiparous users (p = 0.012) than the anterior outer myometrium. Ktrans at the anterior and posterior JZ wall in nulliparous users was lower than in non-users (p = 0.001 and p = 0.013) and Ve at the anterior JZ wall in primiparous users was lower than in non-users (p = 0.044).ConclusionThis study provides data on normal perfusion parameters of inner and outer myometrium, which may be potentially useful in assisted reproductive therapy.     

On the influence of zero-padding on the nonlinear operations in Quantitative Susceptibility Mapping

PurposeZero padding is a well-studied interpolation technique that improves image visualization without increasing image resolution. This interpolation is often performed as a last step before images are displayed on clinical workstations. Here, we seek to demonstrate the importance of zero padding before rather than after performing non-linear post-processing algorithms, such as Quantitative Susceptibility Mapping (QSM). To do so, we evaluate apparent spatial resolution, relative error and depiction of multiple sclerosis (MS) lesions on images that were zero padded prior to, in the middle of, and after the application of the QSM algorithm.Materials and MethodsHigh resolution gradient echo (GRE) data were acquired on twenty MS patients, from which low resolution data were derived using k-space cropping. Pre-, mid-, and post-zero padded QSM images were reconstructed from these low resolution data by zero padding prior to field mapping, after field mapping, and after susceptibility mapping, respectively. Using high resolution QSM as the gold standard, apparent spatial resolution, relative error, and image quality of the pre-, mid-, and post-zero padded QSM images were measured and compared.ResultsBoth the accuracy and apparent spatial resolution of the pre-zero padded QSM was higher than that of mid-zero padded QSM (p < 0.001; p < 0.001), which was higher than that of post-zero padded QSM (p < 0.001; p < 0.001). The image quality of pre-zero padded reconstructions was higher than that of mid- and post-zero padded reconstructions (p = 0.004; p < 0.001).ConclusionZero padding of the complex GRE data prior to nonlinear susceptibility mapping improves image accuracy and apparent resolution compared to zero padding afterwards. It also provides better delineation of MS lesion geometry, which may improve lesion subclassification and disease monitoring in MS patients.     

Diffusion tensor imaging of the cervical spinal cord of patients with Neuromyelitis Optica

BackgroundPrevious studies have demonstrated a correlation between Expanded Disability Status Scale (EDSS) and Diffusion Tensor Imaging (DTI) metrics, but the conclusions were based on evaluations of the entire cervical spinal cord.ObjectivesThe purpose of this study was to quantify the FA and MD values in the spinal cord of NMO patients, separating the lesion sites from the preserved sites, which has not been previously preformed. In addition, we attempted to identify a correlation with EDSS.MethodsDTI was performed in 11 NMO patients and 11 healthy individuals using a 1.5-T MRI scanner. We measured the FA and MD at ROIs positioned along the cervical spinal cord. The mean values of FA and MD at lesion, preserved and spinal cord sites were compared with those of a control group. We tested the correlations between the mean FA and MD with EDSS.ResultsFA in NMO patients was significantly reduced in lesion sites (0.44 vs. 0.55, p = 0.0046), preserved sites (0.46 vs. 0.55, p = 0.0015), and all sites (0.45 vs 0.55, p = 0.0013) while MD increased only in lesion sites (1.03 × 10^− 3 mm²/s vs. 0.90 × 10^− 3 mm²/s, p = 0.009). The FA demonstrated the best correlation with EDSS (r = − 0.7603, p = 0.0086), particularly at lesion sites.ConclusionsThe results reinforce the importance of the FA index and confirm the hypothesis that NMO is a diffuse disease.     

Mechanisms of karyotype differentiation in Cassidinae sensu lato (Coleoptera,Polyphaga, Chrysomelidae) based on seven species of the Brazilian fauna and an overview of the cytogenetic data

Among the subfamilies of Chrysomelidae, Cassidinae sensu lato (s.l.) includes 6000 species distributed in 43 tribes. Approximately 100 of these species were cytogenetically analyzed and most of them presented 2n = 18 = 16 + Xy_p, which was smaller than 2n = 20 = 18 + Xy_p considered basal for Polyphaga. However, some groups of species presented maintenance of the basal diploid number and others showed increase in this number. Certain species of the latter group also exhibited variation in the type of sex chromosome system (SCS). Considering the recent taxonomic revision accomplished for the Cassidinae s.l. species, the existence of phylogenetic relationship for some species of this subfamily, the high diversity of species of this group in the Neotropical region, and the low number of Cassidinae s.l. species karyotyped so far, the aim of the present work was to establish the main mechanisms involved in the karyotype evolution of this subfamily through the study of seven species of the Brazilian fauna and overview of the cytogenetic data. The individuals were collected in southeast and south of Brazil. The chromosomal preparations obtained from embryo and testes of adult males were stained with Giemsa solution. The species Agroiconota inedita (2n = 42 = 40 + Xy_p), Charidotella (s.str.) immaculata (2n = 22 = 20 + Xy_p), Charidotella (s.str.) sexpunctata (2n = 22 = 20 + Xy_p), and Stolas chalybaea (2n = 24 = 22 + Xy_p) revealed diploid number higher than that established as basal for Polyphaga and biarmed chromosomes. The karyotype of Cteisella confusa, Deloyala cruciata, and Metriona elatior showed the chromosomal formulae 2n = 18 = 16 + Xy_p considered modal for Cassidinae s.l. and biarmed chromosomes. The seven species exhibited easily identified sex chromosomes due to their size and/or morphology. The analysis of meiotic cells of all the species showed pachytenes with a positively heteropycnotic block probably corresponding to the sex chromosomes; diplotenes with a high number of bivalents with two chiasmata and sex chromosomes in a parachute configuration, and metaphases II that confirmed the chromosomal morphology, the type of SCS, and the regular segregation of all chromosomes. The data regarding to the number and morphology of the chromosomes, their behaviour during meiosis, and type of SCS were inedit for the majority of these species. In relation to the all Cassidinae s.l. species that presented SCS of the Xy_p type, A. inedita was that with the highest diploid number. Furthermore, this work reported for the first time the cytogenetic information of representatives of the genera Cteisella and Metriona. Taking into account the phylogenetic and cytogenetic data of Cassidinae s.l. species, the karyotype differentiation of this group seems to have occurred from the basal karyotype of Polyphaga by decrease in the chromosome number and subsequent increase in this number. Pericentric inversion, centric fusion and fission seem to have been the main mechanisms that promoted the evolution of the autosomes. However, in the sex chromosome evolution, the mechanisms involved were centric fission and/or chromosomal translocation.     

Water and lipid diffusion MRI using chemical shift displacement-based separation of lipid tissue (SPLIT)

PurposeTo obtain water and lipid diffusion-weighted images (DWIs) simultaneously, we devised a novel method utilizing chemical shift displacement-based separation of lipid tissue (SPLIT) imaging.Materials and methodsSingle-shot diffusion echo-planar imaging without fat suppression was used and the imaging parameters were optimized to separate water and lipid DWIs by chemical shift displacement of the lipid signals along the phase-encoding direction. Using the optimized conditions, transverse DWIs at the maximum diameter of the right calf were scanned with multiple b-values in five healthy subjects. Then, apparent diffusion coefficients (ADCs) were calculated in the tibialis anterior muscle (TA), tibialis bone marrow (TB), and subcutaneous fat (SF), as well as restricted and perfusion-related diffusion coefficients (D and D*, respectively) and the fraction of the perfusion-related diffusion component (F) for TA.ResultsWater and lipid DWIs were separated adequately. The mean ADCs of the TA, TB, and SF were 1.56 ± 0.03 mm²/s, 0.01 ± 0.01 mm²/s, and 0.06 ± 0.02 mm²/s, respectively. The mean D*, D, and F of the TA were 13.7 ± 4.3 mm²/s, 1.48 ± 0.05 mm²/s, and 4.3 ± 1.6%, respectively.ConclusionSPLIT imaging makes it possible to simply and simultaneously obtain water and lipid DWIs without special pulse sequence and increases the amount of diffusion information of water and lipid tissue.     

The first cytogenetic characterization of the poisonous black widow spider Latrodectus gr. curacaviensis from Brazil,with chromosomal review of the family Theridiidae (Arachnida,Araneae)

In this paper we present, for the first time, cytogenetical data on Latrodectus gr. curacaviensis (Theridiidae) from Brazil, as well as the first data on meiosis and sex chromosome system of this genus. Testes were submitted to colchicine, hypotonic, and fixation treatment, and chromosomal preparations were stained with Giemsa solution. The analysis showed 2n = 26 telo/acrocentric chromosomes in spermatogonial metaphases. Metaphase I exhibited 12 autosomal bivalents and two sex chromosome univalents (12II + X₁X₂). All bivalents revealed one terminal chiasma. Metaphases II confirmed the sex chromosome system, showing 12 autosomes or 12 autosomes plus two X chromosomes, respectively. Male karyotype prevailing in theridiids is formed by 2n = 22 chromosomes, including sex chromosome system X₁X₂ in all species. The Latrodectus species of the geometricus clade analyzed until now showed smaller diploid number (2n♀ = 16 and 2n♀ = 18) than the species of the mactans clade (2n♀ = 24 and 2n♀ = 26). Thus, according to the chromosome number, the examined Latrodectus species seems to be related to the mactans clade.