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Accurate diagnosis of vertebral osteoporotic fractures is crucial for the identification of individuals at high risk of future fractures. Different methods for radiological assessment of vertebral fractures exist, but a gold standard is lacking. The aim of our study was to estimate statistical measures of agreement and prevalence of osteoporotic vertebral fractures in the population-based Rotterdam Study, across two assessment methods. The quantitative morphometry assisted by SpineAnalyzer® (QM SA) method evaluates vertebral height loss that affects vertebral shape whereas the algorithm-based qualitative (ABQ) method judges endplate integrity and includes guidelines for the differentiation of vertebral fracture and nonfracture deformities. Cross-sectional radiographs were assessed for 7582 participants aged 45 to 95 years. With QM SA, the prevalence was 14.2% (95% CI, 13.4% to 15.0%), compared to 4.0% (95% CI, 3.6% to 4.5%) with ABQ. Inter-method agreement according to kappa (κ) was 0.24. The highest agreement between methods was among females (κ = 0.31), participants age >80 years (κ = 0.40), and at the L1 level (κ = 0.40). With ABQ, most fractures were found at the thoracolumbar junction (T12–L1) followed by the T7–T8 level, whereas with QM SA, most deformities were in the mid thoracic (T7–T8) and lower thoracic spine (T11–T12), with similar number of fractures in both peaks. Excluding mild QM SA deformities (grade 1 with QM) from the analysis increased, the agreement between the methods from κ = 0.24 to 0.40, whereas reexamining mild deformities based on endplate depression increased agreement from κ = 0.24 to 0.50 (p

Background: Altered perfusion might play an important role in the pathophysiology of patellofemoral pain (PFP), a common knee complaint with unclear pathophysiology. Purpose: To investigate differences in dynamic contrast-enhanced (DCE)-MRI perfusion parameters between patients with PFP and healthy control subjects. Population/Subjects/Phantom/Specimen/Animal Model: Thirty-five adult patients with PFP and 44 healthy adult control subjects. Field Strength/Sequence: 3T DCE-MRI consisting of a sagittal, anterior-posterior, frequency-encoded, fat-suppressed 3D spoiled gradient-echo sequence with intravenous contrast administration. Assessment: Patellar bone volumes of interest (VOIs) were delineated by a blinded observer. Quantitative perfusion parameters (kep and ktrans) were calculated from motion-compensated DCE-MRI data by fitting Tofts' model. Weighted mean and unweighted median values of kep and ktrans were computed within the patellar bone VOIs. Statistical Tests: Differences in patellar bone perfusion parameters were compared between groups by linear regression analyses, adjusted for confounders. Results: Mean differences of weighted mean and unweighted median were 0.0039 (95% confidence interval [CI] –0.0013; 0.0091) and 0.0052 (95% CI –0.0078; 0.018) for ktrans, and 0.046 (95% CI –0.021; 0.11) and 0.069 (95% CI –0.017; 0.15) for kep, respectively. All perfusion parameters were not significantly different between groups (P-values: 0.32; 0.47 for ktrans, and 0.24; 0.15) for kep. However, a significant difference in variance between populations was observed for ktrans (P-value 0.007). Data Conclusion: Higher patellar bone perfusion parameters were found in patients with PFP when compared to healthy control subjects, but these differences were not statistically significant. This result, and the observed significant difference in ktrans variance, warrant further research. Level of Evidence: 1. Technical Efficacy: Stage 3. J. Magn. Reson. Imaging 2018;47:1344–1350.

An apparatus (10) is disclosed for assisting a medical specialist in providing a diagnosis of a medical condition of a mammal brain. The apparatus (10) includes an input facility (12), a conversion facility (14l, 14r), and an output device (16). In an operational mode the input facility receives a first value (VL) indicative of a brain characteristic of a portion of the first part of the brain for a point in time and a second value (VR) indicative of a brain characteristic of a corresponding portion of the right part of the brain for said point in time. The input facility further receives first reference data (VRL) indicative for a cumulative distribution of the first value for said portion in a reference population and second reference data (VRR) indicative for a cumulative distribution of the second value for the corresponding portion in the reference population. The conversion facility (14L, 14R) determines a third and a fourth value (VRL, VRR). The third value indicates the cumulative probability of the first value according to the first reference data. The fourth value indicates the cumulative probability of the second value according to the second reference data. The output device (16) generates a human accessible output signal (SH) which is indicative for a substantially monotonically increasing function of a difference between the third and the fourth value.

Cationic liposomes carrying high [Gd] can be used as efficient cell-labeling agents. In a compartmentalized state, Gd can cause signal loss (relaxivity quenching). The contributions of liposomal [Gd], size and compartmentalization state to relaxivity quenching were assessed. The dependency of signal intensity (SI) on intraliposomal [Gd] was assessed comparing three different [Gd] (0.3, 0.6 and 1.0M Gd) in both small (80 nm) and large (120 nm) cationic liposomes. In addition, five compartmentalization states were compared: free Gd, intact Gd liposomes, ruptured Gd liposomes, Gd liposomes in intact cells and Gd liposomes in ruptured cells (simulating cell death). Gd also causes R2 effects, which is often overlooked. Therefore, both R1 and R2 relaxation rates of a dilution range were measured by T1 and T2 mapping on a 7T clinical scanner. Less is more. As the unidirectional water efflux rate (outbound across the liposome membrane, κle) is proportional to the surface:volume ratio, smaller liposomes yielded a consistently higher R1 than larger liposomes. For equal voxel [Gd] less concentrated liposomes (0.3M Gd) yielded higher R1/R2 ratio because of the higher extraliposomal water fraction (vl). Gd exhibits a dualistic behavior: from hypointensity to hyperintensity to hypointensity, with decreasing [Gd]. Regarding compartmentalization, fewer membrane barriers means a higher R1/R2 ratio. Gd liposomes exhibit a versatile contrast behavior, dependent on the compartmentalization state, liposomal size, intraliposomal [Gd] and liposome number. Both R1 and R2 effects contribute to this. The versatility allows one to tailor the optimal liposomal formulation to desired goals in cell labeling and tracking.

In cell therapy, noninvasive monitoring of in vivo cell fate is challenging. In this study we investigated possible differences in R1, R2 or R2* relaxation rate as a measure of overall cell viability for mesenchymal stem cells labeled with Gd-liposomes (Gd-MSCs) or iron oxide nanoparticles (SPIO-MSCs). Cells were also transduced with a luciferase vector, facilitating a correlation between MRI findings and cell viability using bioluminescence imaging (BLI). Viable Gd-MSCs were clearly distinguishable from nonviable Gd-MSCs under both in vitro and in vivo conditions, clearly differing quantitatively (ΔR1 and ΔR2) as well as by visual appearance (hypo- or hyperintense contrast). Immediately post-injection,viable Gd-MSCs caused a substantially larger ΔR2 and lower ΔR1 effect compared with nonviable MSCs. With time, the ΔR1 and ΔR2 relaxation rate showed a good negative correlation with increasing cell number following proliferation. Upon injection, no substantial quantitative or visual differences between viable and nonviable SPIO-MSCs were detected. Moreover, nonviable SPIO-MSCs caused a persisting signal void in vivo, compromising the specificity of this contrast agent. In vivo persistence of SPIO particles was confirmed by histological staining. A large difference was found between SPIO- and Gd-labeled cells in the accuracy of MR relaxometry in assessing the cell viability status. Gd-liposomes provide a more accurate and specific assessment of cell viability than SPIO particles. Viable Gd cells can be differentiated from nonviable Gd cells even by visual interpretation. These findings clearly indicate Gd to be the favourable contrast agent in qualitative and quantitative evaluation of labeled cell fate in future cell therapy experiments.

The purpose of the study was to show the feasibility of quantification in the case of cell death, cell migration and cell division by parametric MRI. We identify limitations for quantitative cell tracking owing to mixed parallel processes. Various intravoxel SPIO-labeled cell, super paramagnetic iron oxide particles (SPIO) and micron-sized paramagnetic iron oxide (MPIO) particle distributions were prepared by methods mimicking biologically relevant processes (compartmentalization, migration, division and cell death). R 2* and R 2 relaxometry measurements were performed at 3.0T; iron concentration was measured by optical emission spectrometry. The effects of spatial distribution and compartmentalization of paramagnetic iron-oxide particles on relaxivity were analyzed. Assessment of R 2′ (R 2*-R 2) allowed differentiation between intracellular and extracellular SPIO only if no high-iron-content extracellular particles were present. Relaxivity was sensitive to variations in cell labeling. Samples of the same cell types embedded in the same suspension media at the same cell density produced different relaxivity values, depending on the preparation of the labeled cells. In the case of cell division, a unique relationship between relaxation rate and iron concentration was found, where the relaxivity proved to be independent of initial cell labeling. In case of cell mixing, the cell density could be derived from relaxation values, even if iron concentration was undetermined. We demonstrated that relaxometry does not allow labeled cell quantification when multiple physiological processes such as cell division and cell migration coexist. The measured transversal relaxation rates were sensitive to the labeling technique. However, under special circumstances, despite the numerous limiting factors, quantification of the number of labeled cells by relaxometry was feasible.

Purpose: To retrospectively evaluate renal, vascular, and urinary tract visualization following a single postcontrast multidetector computed tomographic (CT) urographic sequence performed with three limited-volume bolus injections. Materials and Methods: The institutional review board approved this retrospective study. Patient informed consent was waived. Triple-bolus multidetector CT urography was performed in 110 patients. Triple-bolus protocol consisted of 30 mL of contrast material at 2 mL/sec at 0 seconds, 50 mL at 1.5 mL/sec at 435 seconds, 65 mL at 3 mL/sec at 488 seconds, with total abdominal scanning time of 510 seconds. Two independent readers rated urinary tract opacification and qualitatively and quantitatively assessed renal parenchymal and vascular contrast enhancement. Upper urinary tract (UUT) distention was measured by one reader. Interobserver agreement was assessed by using kappa statistics. Results: Complete opacification of the intrarenal collecting system and proximal ureter was achieved in 91% (184 of 202) (kappa = 0.62) and 82% (166 of 202) (kappa = 0.94) of segments, respectively. The distal ureter was not opacified in 21% of the cases (kappa = 0.92), and the bladder was not opacified in 20% of the cases. Mean distention was higher for proximal (3.9 mm) than for distal (3.7 mm) segments. Image quality of renal parenchymal enhancement was excellent in 76% of cases. Arteries showed better contrast enhancement than veins (excellent rating in 89% vs 59% of the cases). Radiation dose calculated for triple-bolus acquisition was 9.8 mSv. Conclusion: Triple-bolus multidetector CT urography is a dose-efficient protocol acquiring corticomedullary-nephrographic-excretory and vascular enhancement phases in a single acquisition and provides sufficient opacification and distention of the UUT. Simultaneously, adequate image quality of renal parenchyma and vascular anatomy is achieved. (C) RSNA, 2010