-
1.
Concordance in the interpretation of PET after chemotherapy in advanced stage Hodgkin lymphoma.
Kobe, C, Kuhnert, G, Haverkamp, H, Fuchs, M, Kahraman, D, Eich, HT, Kriz, J, Baues, C, Nast-Kolb, B, Bröckelmann, PJ, et al
Nuklearmedizin. Nuclear medicine. 2015;(6):241-6
Abstract
UNLABELLED The aim was to analyze the degree of agreement between the central review panel and the local PET interpretation within the HD15 trial and its impact on subsequent treatment and progression free survival. PATIENTS, METHODS The analysis set consisted of 739 patients with residues ≥ 2.5 cm after 6 or 8 cycles of BEACOPPesc from the HD15 trial performed by the German Hodgkin Study Group. The recommendation for or against further radiotherapy was based on the central [(18)F]FDG-PET interpretation. Central PET interpretation was compared to the local PET interpretation and concordance was measured using Cohen's Kappa coefficient. Prognostic impact of the analysis of concordance between local and central PET interpretations was evaluated using progression free survival (PFS); groups were compared with the log rank test. RESULTS The central panel rated 548 of 739 patients (74%) as PET negative. Of these, 513 were also rated as PET negative in the local PET interpretation. PET positivity was seen by central reviewers in the remaining 191 patients (26%), in concordance with local reviewers in 155 cases. Even though substantial agreement was found (Cohen's Kappa 0.81), the interpretation of the central PET review panel led to a different therapeutic recommendation in 71/739 (10%) patients. PFS was equally high in groups in which the therapeutic regime had been changed on the basis of the central panel decision. CONCLUSION High concordance is found between local and central reviewers with regard to PET interpretation in residual tissue after intense chemotherapy. The existence of the central PET review panel allows the identification of additional patients as PET negative so that radiotherapy can be safely omitted (35 of 548 patients = 4.7%).
-
2.
Changes in brain regions associated with food-intake regulation, body mass and metabolic profiles during acute antipsychotic treatment in first-episode schizophrenia.
Emsley, R, Asmal, L, Chiliza, B, du Plessis, S, Carr, J, Kidd, M, Malhotra, AK, Vink, M, Kahn, RS
Psychiatry research. 2015;(2):186-93
Abstract
We investigated whether morphological brain changes occurred in brain regions associated with body-weight homeostasis during acute antipsychotic treatment, and if so, whether they were related to changes in body mass and metabolic profile. Twenty-two antipsychotic-naive patients with first-episode schizophrenia received either risperidone long acting injection or flupenthixol decanoate over 13 weeks and were compared by structural MRI with 23 matched healthy volunteers at weeks 0, 4 and 13. Images were reconstructed using freesurfer fully-automated whole brain segmentation. The ventral diencephalon and prefrontal cortex were selected to represent the homeostatic and hedonic food intake regulatory systems respectively. Body mass was measured at weeks 0, 7 and 13 and fasting glucose and lipid profiles at weeks 0 and 13. Linear mixed effect models indicated significant group(⁎)time interactions for the ventral diencephalon volumes bilaterally. Ventral diencephalon volume reduction was strongly correlated bilaterally with body mass increase and HDL-cholesterol reductions, and unilaterally with blood glucose elevation. There were no significant changes in prefrontal cortical thickness. These findings implicate the ventral diencephalon, of which the hypothalamus is the main component, in the acute adipogenic and dyslipidaemic effects of antipsychotic medication.
-
3.
Contrast-enhanced ultrasound using real-time contrast harmonic imaging in invasive breast cancer: comparison of enhancement dynamics with three different doses of contrast agent.
Saracco, A, Szabó, BK, Aspelin, P, Leifland, K, Tánczos, E, Wilczek, B, Axelsson, R
Acta radiologica (Stockholm, Sweden : 1987). 2015;(1):34-41
Abstract
BACKGROUND In the last few years new potential applications have been developed for contrast-enhanced ultrasound (CEUS) and the management of breast diseases, but there is still some debate concerning the optimal dose to evaluate breast lesions, especially as a diagnostic tool. PURPOSE To compare different CEUS doses of injected contrast agent in order to establish an optimal dose for the diagnosis of invasive breast cancer. MATERIAL AND METHODS In Group A we compared the bolus dose of 1.2 mL vs. 2.4 mL and in Group B we compared the bolus dose of 2.4 mL vs. 4.8 mL (26 and 25 invasive carcinomas, respectively). CEUS was performed in real-time contrast harmonic imaging (CHI) using a L9-3 MHz probe. All examinations were recorded in a contrast side/side imaging mode loop for 120 s. Wash-in and wash-out patterns of the contrast agent were analyzed with advanced US quantification software and kinetic curves were used for statistical analysis. RESULTS In Group B (2.4 mL vs. 4.8 mL), more and stronger correlation was found among kinetic parameters (area under the curve, P < 0.00001; lognormal model parameters, μ, P = 0.0007 and σ, P < 0.0001; mean transit time, P < 0.0001; model-based wash-out ratios, W21m, P = 0.0002; W50m, P = 0.0001; time-to-peak, P = 0.005) as compared to Group A (1.2 mL vs. 2.4 mL). CONCLUSION The optimal way to evaluate kinetic features of invasive breast tumors using real-time CEUS is with an injection of contrast agent of either 2.4 mL or 4.8 mL.
-
4.
Subclinical left ventricular systolic dysfunction in diabetic patients and its association with retinopathy: A 2D speckle tracking echocardiography study.
Karagöz, A, Bezgin, T, Kutlutürk, I, Külahçıoğlu, S, Tanboğa, IH, Güler, A, Karabay, CY, Oduncu, V, Aksoy, H, Kırma, C
Herz. 2015;:240-6
Abstract
AIM: It is important to diagnose diabetic cardiomyopathy in the early stages to prevent development of evident heart failure in the future. The primary objective of this study was to evaluate the presence of subclinical left ventricular (LV) dysfunction with two-dimensional (2D) speckle tracking echocardiography (STE) and the secondary objective was to compare retinopathy-positive and -negative diabetic patients. PATIENTS AND METHODS A total of 82 patients with type II diabetes mellitus (DM) and 90 gender-matched healthy controls were included. Retinopathy was present in 55 patients in the study group. All study participants underwent conventional 2D echocardiography and STE. RESULTS All diabetic patients had preserved LV ejection fraction (LV-EF ≥ 50). Compared with the control group, diabetic patients had a larger left atrium (47.3 ± 19.9 mm vs. 36.9 ± 17.8 mm, p < 0.001) and a higher E/Em ratio (12.0 ± 2.9 vs. 10.5 ± 3.7, p = 0.004). The LV-EF, LV end diastolic and end systolic volumes, E/A ratios, deceleration times, and tissue Doppler parameters were compared between groups. The study group was observed to have statistically significant lower four-chamber (4C; 17.7 ± 3.0 % vs. 19.3 ± 3.5 %, p = 0.002), three-chamber (3C; 17.5 ± 3.0 % vs. 19.2 ± 3.4 %, p = 0.001), and two-chamber (2C; 18.5 ± 3.5 % vs. 20.1 ± 2.4 %, p = 0.001) peak longitudinal strain values compared with the control group. Moreover, LV global strain values were found to be significantly lower in the DM group than in the control group (17.9 ± 2.7 % vs. 21.1 ± 3.2 %, p < 0.001). By contrast, basal rotation (4.9 ± 3.3° vs.2.8 ± 4.5°, p = 0.001), apical rotation (15.3 ± 6.7° vs. 12.1 ± 5.3°, p = 0.001) and LV twist (20.2 ± 7.2° vs. 16.9 ± 6.5°, p = 0.002) in the DM group were significantly increased compared with those of controls. CONCLUSION The STE procedure can be a useful novel technique in the determination of subclinical LV dysfunction in diabetic patients. Diabetic patients have lower longitudinal myocardial mechanics, and circumferential and rotational mechanics are impaired. There was no significant association between diabetic retinopathy and LV function.
-
5.
Enhanced axonal metabolism during early natalizumab treatment in relapsing-remitting multiple sclerosis.
Wiebenga, OT, Klauser, AM, Schoonheim, MM, Nagtegaal, GJ, Steenwijk, MD, van Rossum, JA, Polman, CH, Barkhof, F, Pouwels, PJ, Geurts, JJ
AJNR. American journal of neuroradiology. 2015;(6):1116-23
Abstract
BACKGROUND AND PURPOSE The considerable clinical effect of natalizumab in patients with relapsing-remitting multiple sclerosis might be explained by its possible beneficial effect on axonal functioning. In this longitudinal study, the effect of natalizumab on absolute concentrations of total N-acetylaspartate, a marker for neuronal integrity, and other brain metabolites is investigated in patients with relapsing-remitting multiple sclerosis by using MR spectroscopic imaging. MATERIALS AND METHODS In this explorative observational study, 25 patients with relapsing-remitting multiple sclerosis initiating natalizumab treatment were included and scanned every 6 months for 18 months. Additionally 18 matched patients with relapsing-remitting multiple sclerosis continuing treatment with interferon-β or glatiramer acetate were included along with 12 healthy controls. Imaging included short TE 2D-MR spectroscopic imaging with absolute metabolite quantification of total N-acetylaspartate, creatine and phosphocreatine, choline-containing compounds, myo-inositol, and glutamate. Concentrations were determined for lesional white matter, normal-appearing white matter, and gray matter. RESULTS At baseline in both patient groups, lower concentrations of total N-acetylaspartate and creatine and phosphocreatine were found in lesional white matter compared with normal-appearing white matter and additionally lower glutamate in lesional white matter of patients receiving natalizumab. In those patients, a significant yearly metabolite increase was found for lesional white matter total N-acetylaspartate (7%, P < .001), creatine and phosphocreatine (6%, P = .042), and glutamate (10%, P = .028), while lesion volumes did not change. In patients receiving interferon-β/glatiramer acetate, no significant change was measured in lesional white matter for any metabolite, while whole-brain normalized lesion volumes increased. CONCLUSIONS Patients treated with natalizumab showed an increase in total N-acetylaspartate, creatine and phosphocreatine, and glutamate in lesional white matter. These increasing metabolite concentrations might be a sign of enhanced axonal metabolism.
-
6.
Cardiac calcium score on 2D echo: correlations with cardiac and coronary calcium at multi-detector computed tomography.
Gaibazzi, N, Baldari, C, Faggiano, P, Albertini, L, Faden, G, Pigazzani, F, Rossi, C, Reverberi, C
Cardiovascular ultrasound. 2014;:43
Abstract
BACKGROUND To test the hypothesis that a semi-quantitative echocardiographic calcium score (eCS) significantly correlates with cardiac calcium measured by coronary computed tomography angiography (CCTA) and, secondarily, severe coronary artery calcifications and stenosis. METHODS This is a retrospective, observational study, conducted in a tertiary centre. eCS was compared with CCTA scores of non-coronary cardiac calcium (nCACS), coronary cardiac calcium (CACS) and number of diseased coronary vessels, in 141 subjects without known coronary artery disease (CAD), who underwent both echocardiography and CCTA for clinical reasons. RESULTS Age, prevalence of hypertension and all measures of calcium (eCS, nCACS and CACS) differed significantly between the no-CAD and CAD subgroups. eCS was positively correlated with nCACS (Spearman rho = 0.64, p < 0.0001), CACS (rho = 0.46, p < 0.01) and weakly with the number of diseased coronary vessels (rho = 0.28, p < 0.05). eCS and nCACS had similar area under the curve (AUC) for the prediction of severe CACS (≥400) (0.77, 95% CI 0.68-0.86 and 0.79, 95% CI 0.72-0.88) or obstructive CAD (0.63, 95% CI 0.54-0.72 and 0.63, 95% CI 0.55-0.73). CONCLUSIONS eCS, a calcium score easily obtainable during standard echocardiography, is moderately to strongly correlated with nCACS by CCTA. The full eCS score correlates with nCACS better than its single components. It correlates with CACS and predicts severe coronary calcification (CACS > 400), a known predictor of cardiovascular morbidity and mortality. The eCS also predicts obstructive CAD, incrementally to age and clinical variables, although for this purpose CACS remains the most accurate score.
-
7.
DCE-MRI of the liver: effect of linear and nonlinear conversions on hepatic perfusion quantification and reproducibility.
Aronhime, S, Calcagno, C, Jajamovich, GH, Dyvorne, HA, Robson, P, Dieterich, D, Fiel, MI, Martel-Laferriere, V, Chatterji, M, Rusinek, H, et al
Journal of magnetic resonance imaging : JMRI. 2014;(1):90-8
-
-
Free full text
-
Abstract
PURPOSE To evaluate the effect of different methods to convert magnetic resonance (MR) signal intensity (SI) to gadolinium concentration ([Gd]) on estimation and reproducibility of model-free and modeled hepatic perfusion parameters measured with dynamic contrast-enhanced (DCE)-MRI. MATERIALS AND METHODS In this Institutional Review Board (IRB)-approved prospective study, 23 DCE-MRI examinations of the liver were performed on 17 patients. SI was converted to [Gd] using linearity vs. nonlinearity assumptions (using spoiled gradient recalled echo [SPGR] signal equations). The [Gd] vs. time curves were analyzed using model-free parameters and a dual-input single compartment model. Perfusion parameters obtained with the two conversion methods were compared using paired Wilcoxon test. Test-retest and interobserver reproducibility of perfusion parameters were assessed in six patients. RESULTS There were significant differences between the two conversion methods for the following parameters: AUC60 (area under the curve at 60 s, P < 0.001), peak gadolinium concentration (Cpeak, P < 0.001), upslope (P < 0.001), Fp (portal flow, P = 0.04), total hepatic flow (Ft, P = 0.007), and MTT (mean transit time, P < 0.001). Our preliminary results showed acceptable to good reproducibility for all model-free parameters for both methods (mean coefficient of variation [CV] range, 11.87-23.7%), except for upslope (CV = 37%). Among modeled parameters, DV (distribution volume) had CV <22% with both methods, PV and MTT showed CV <21% and <29% using SPGR equations, respectively. Other modeled parameters had CV >30% with both methods. CONCLUSION Linearity assumption is acceptable for quantification of model-free hepatic perfusion parameters while the use of SPGR equations and T1 mapping may be recommended for the quantification of modeled hepatic perfusion parameters.
-
8.
Quantitative evaluation of liver function with T1 relaxation time index on Gd-EOB-DTPA-enhanced MRI: comparison with signal intensity-based indices.
Kamimura, K, Fukukura, Y, Yoneyama, T, Takumi, K, Tateyama, A, Umanodan, A, Shindo, T, Kumagae, Y, Ueno, S, Koriyama, C, et al
Journal of magnetic resonance imaging : JMRI. 2014;(4):884-9
Abstract
PURPOSE To evaluate whether the reduction rate of T1 relaxation time of the liver (T1 relaxation time index) before and 20 minutes after gadolinium-ethoxybenzyl-diethylenetriaminepentaacetic acid (Gd-EOB-DTPA) injection has the potential to serve as an magnetic resonance imaging (MRI)-based liver function test in comparison with signal intensity-based indices. MATERIALS AND METHODS Ninety-nine patients with suspected liver lesions underwent Gd-EOB-DTPA-enhanced MRI. T1 maps using 3D T1-weighted gradient-echo volumetric interpolated examination with two different flip angles were also performed before and 20 minutes after Gd-EOB-DTPA administration. T1 relaxation time index was compared with four signal intensity-based indices in terms of the ability to discriminate Child-Pugh A (CPA) and Child-Pugh B (CPB) from normal liver function (NLF), and in terms of its correlation with indocyanine green (ICG) clearance. RESULTS Twenty-four patients were classified as NLF, 64 patients were classified as CPA, and 11 were classified as CPB group. The T1 relaxation time index was significantly lower for CPA (0.62 ± 0.08 vs. 0.68 ± 0.07, P = 0.021) and CPB (0.55 ± 0.15 vs. 0.68 ± 0.07, P < 0.001) than for NLF. All signal intensity-based indices showed significant differences only when comparing NLF and CPB. The correlation coefficient with ICG clearance was the highest for T1 relaxation time index (r = -0.605, P < 0.001). CONCLUSION The T1 relaxation time index has the potential to serve as an MRI-based liver function test, and is most strongly correlated with ICG clearance among the Gd-EOB-DTPA MRI-based indices investigated.
-
9.
Comparison of T1 relaxation times in adipose tissue of severely obese patients and healthy lean subjects measured by 1.5 T MRI.
Garnov, N, Linder, N, Schaudinn, A, Blüher, M, Karlas, T, Schütz, T, Dietrich, A, Kahn, T, Busse, H
NMR in biomedicine. 2014;(9):1123-8
Abstract
Subcutaneous (SAT) and visceral adipose tissue (VAT) differ in composition, endocrine function and localization in the body. VAT is considered to play a role in the pathogenesis of insulin resistance, type 2 diabetes, fatty liver disease, and other obesity-related disorders. It has been shown that the amount, distribution, and (cellular) composition of adipose tissue (AT) correlate well with metabolic conditions. In this study, T1 relaxation times of AT were measured in severely obese subjects and compared with those of healthy lean controls. Here, we tested the hypothesis that T1 relaxation times of AT differ between lean and obese individuals, but also between VAT and SAT as well as superficial (sSAT) and deep SAT (dSAT) in the same individual. Twenty severely obese subjects (BMI 41.4 ± 4.8 kg/m(2) ) and ten healthy lean controls matched for age (BMI 21.5 ± 1.9 kg/m(2) ) underwent MRI at 1.5 T using a single-shot fast spin-echo sequence (short-tau inversion recovery) at six different inversion times (TI range 100-1000 ms). T1 relaxation times were computed for all subjects by fitting the TI -dependent MR signal intensities of user-defined regions of interest in both SAT and VAT to a model function. T1 times in sSAT and dSAT were only measured in obese patients. For both obese patients and controls, the T1 times of SAT (275 ± 14 and 301 ± 12 ms) were significantly (p < 0.01) shorter than the respective values in VAT (294 ± 20 and 360 ± 35 ms). Obese subjects also showed significant (p < 0.01) T1 differences between sSAT (268 ± 11 ms) and dSAT (281 ± 19 ms). More important, T1 differences in both SAT and VAT were highly significant (p < 0.001) between obese patients and healthy subjects. The results of our pilot study suggest that T1 relaxation times differ between severely obese patients and lean controls, and may potentially provide an additional means for the non-invasive assessment of AT conditions and dysfunction.
-
10.
Binary classification of ¹⁸F-flutemetamol PET using machine learning: comparison with visual reads and structural MRI.
Vandenberghe, R, Nelissen, N, Salmon, E, Ivanoiu, A, Hasselbalch, S, Andersen, A, Korner, A, Minthon, L, Brooks, DJ, Van Laere, K, et al
NeuroImage. 2013;:517-25
Abstract
(18)F-flutemetamol is a positron emission tomography (PET) tracer for in vivo amyloid imaging. The ability to classify amyloid scans in a binary manner as 'normal' versus 'Alzheimer-like', is of high clinical relevance. We evaluated whether a supervised machine learning technique, support vector machines (SVM), can replicate the assignments made by visual readers blind to the clinical diagnosis, which image components have highest diagnostic value according to SVM and how (18)F-flutemetamol-based classification using SVM relates to structural MRI-based classification using SVM within the same subjects. By means of SVM with a linear kernel, we analyzed (18)F-flutemetamol scans and volumetric MRI scans from 72 cases from the (18)F-flutemetamol phase 2 study (27 clinically probable Alzheimer's disease (AD), 20 amnestic mild cognitive impairment (MCI), 25 controls). In a leave-one-out approach, we trained the (18)F-flutemetamol based classifier by means of the visual reads and tested whether the classifier was able to reproduce the assignment based on visual reads and which voxels had the highest feature weights. The (18)F-flutemetamol based classifier was able to replicate the assignments obtained by visual reads with 100% accuracy. The voxels with highest feature weights were in the striatum, precuneus, cingulate and middle frontal gyrus. Second, to determine concordance between the gray matter volume- and the (18)F-flutemetamol-based classification, we trained the classifier with the clinical diagnosis as gold standard. Overall sensitivity of the (18)F-flutemetamol- and the gray matter volume-based classifiers were identical (85.2%), albeit with discordant classification in three cases. Specificity of the (18)F-flutemetamol based classifier was 92% compared to 68% for MRI. In the MCI group, the (18)F-flutemetamol based classifier distinguished more reliably between converters and non-converters than the gray matter-based classifier. The visual read-based binary classification of (18)F-flutemetamol scans can be replicated using SVM. In this sample the specificity of (18)F-flutemetamol based SVM for distinguishing AD from controls is higher than that of gray matter volume-based SVM.