Ventricular Volume Measurements Research Articles

Comparison of single-plane and biplane area-length methods for right ventricular volume calculation: In vivo and vitro study

Currently, both single-plane and biplane area-length methods by two-dimensional echocardiography were commonly used for calculating RV volume in clinical practice, however, little is known regarding the correlation between the two modalities. We try to assess the accuracy of ventricular volume measurement of single-plane and biplane area-length methods by both in-vitro and in-vivo studies.

Measurement of left and right ventricular volumes with tomographic equilibrium radionuclide angiocardiography and cardiac MRI

We previously developed an operator-interactive method for the measurement of left ventricular (LV) and right ventricular (RV) ejection fraction (EF) and end-systolic volume (ESV) and end-diastolic volume (EDV) using single-photon emission tomographic equilibrium radionuclide angiocardiography (SPECT ERNA). We aimed to compare our SPECT ERNA method with cardiac MRI (CMRI) for the determination of ventricular measures. Paired measurements of LV and RV EFs and ESV and EDV were carried out by SPECT ERNA and CMRI in a group of patients who had myocardial infarction due to left anterior descending coronary artery thrombosis. SPECT ERNA and CMRI provided similar estimations of the mean (SD) LV ESV [61 (23) vs. 61 (32) ml; P=0.99] and LV EDV [134 (29) vs. 141 (44) ml; P=0.28]. The mean (SD) LV EF by SPECT ERNA was slightly but significantly smaller than that by CMRI [0.55 (0.10) vs. 0.58 (0.11) ml; P=0.03]. SPECT ERNA, compared with CMRI, produced similar mean (SD) values of RV ESV [62 (17) vs. 67 (17) ml; P=0.10] and RV EDV [153 (28) vs. 149 (29) ml; P=0.51] and somewhat larger mean (SD) RV EF [0.60 (0.06) vs. 0.55 (0.06) ml; P<0.001]. Excellent correlations were found between SPECT ERNA and CMRI for combined LV ESV and EDV (R=0.85, P<0.001) and combined RV ESV and EDV (R=0.85, P<0.001). This study further validates SPECT ERNA as a method to measure LV and RV EF, ESV, and EDV.

Rapid microcomputed tomography suggests cardiac enlargement occurs during conductance catheter measurements in mice

Conductance catheters (CC) represent an established method of determining cardiac function in mice; however, the potentially detrimental effects a catheter may have on the mouse heart have never been evaluated. The present study takes advantage of rapid three-dimensional (3D) microcomputed tomography (CT) to compare simultaneously acquired micro-CT and CC measurements of left ventricular (LV) volumes in healthy and infarcted mice and to determine changes in LV volume and function associated with CC insertion. LV volumes were measured in C57BL/6 mice (10 healthy, 10 infarcted, 2% isoflurane anesthesia) using a 1.4-Fr Millar CC. 3D micro-CT images of each mouse were acquired before CC insertion as well as during catheterization. Each CT scan produced high-resolution images throughout the entire cardiac cycle in <1 min, enabling accurate volume measurements as well as direct visualization of the CC within the LV. Bland-Altman analysis demonstrated that CC measurements underestimate volume compared with CT measurements in both healthy [bias of -18.4 and -28.9 μl for end-systolic (ESV) and end-diastolic volume (EDV), respectively] and infarcted mice (ESV = -51.6 μl and EDV = -71.7 μl); underestimation was attributed to the off-center placement of the catheter. Individual evaluation of each heart revealed LV dilation following CC insertion in 40% of mice in each group. No change in ejection fraction was observed, suggesting the enlargement was caused by volume overload associated with disruption of the papillary muscles or chords. The enlargement witnessed was not significant; however, the results suggest the potential for CC insertion to detrimentally affect mouse myocardium, necessitating further investigation.

Non-Invasive Cardiac Output Monitoring in Neonates Using Bioreactance: A Comparison with Echocardiography

Objectives: Non-invasive cardiac output monitoring is a potentially useful clinical tool in the neonatal setting. Our aim was to evaluate a new method of non-invasive continuous cardiac output (CO) measurement (NICOM™) based on the principle of bioreactance in neonates. Methods: In this prospective observational study, 10 neonates underwent 97 paired NICOM and echocardiography (echo) assessments of left ventricular output (LVO). For each neonate, NICOM measurements of left ventricular stroke volume (SV) and LVO over a 2- to 4-hour period were correlated with blinded, simultaneous, discrete echo measurements of SV and LVO. The precision and accuracy of the NICOM monitor relative to echo during periods of steady state were assessed. Results: The infants’ median birth weight was 2.72 kg (IQR 1.56–3.23 kg, range 1.44–4.00) and their median gestation was 37 weeks (IQR 31–40 weeks, range 31–41). Median NICOM SV and LVO readings were consistently lower than echo (2.6 ml [IQR 1.4–3.2, range 0.6–5.3] vs. 3.5 ml [IQR 2.1–4.4, range 1.1–6.8], and 400 ml/min [IQR 233–476] vs. 559 ml/min [IQR 386–652], p < 0.001). The NICOM LVO readings were lower than the echo readings by a mean of 153 ± 56 ml/kg. NICOM consistently under-read LVO by 31 ± 8%, and this systematic difference was constant across the range of LVOs obtained. There was a strong correlation between NICOM and echo measurements of LVO (r = 0.95, p < 0.001). Conclusion: Non-invasive cardiac output monitoring is feasible in neonates. Further validation studies in neonatal animal experimental models and human neonates need to be conducted before routine clinical use.

Assessment of cardiac function in mice using ventricular catheterization and MRI derived Pressure‐Volume loops

Stroke work normalized to end diastolic volume derived from pressure‐ volume (PV) relationships is regarded as a gold standard for measurement of the contractile status. Though conductance catheters are widely used to obtain PV relationships in the heart, it does not provide accurate measurements of absolute ventricular volumes. Magnetic resonance imaging (MRI) on the other hand provides accurate measurement of Left ventricular (LV) cavity volume but does not provide absolute measurement of LV pressure. The aim of this study was to demonstrate the feasibility of obtaining MRI volume data while invasively measuring LV pressure in wild type C57BL/6 and δ sarcoglycan null (Scgd−/−). LV pressure was measured invasively using a MR compatible fluid filled pressure transducer and volume data collected simultaneously from a 7 Tesla scanner at rest and during infusion of Dobutamine. Stroke work was calculated from the integrated area within the PV loop. Stroke work of Scgd−/− decreased from 2.8±0.56 mmHg mL at rest to 1.1±0.49 mmHg mL at stress but did not change significantly in WT. Decreased stroke work in Scgd−/− mice under stress was associated with LV pressure decline which may be related to vascular abnormalities in these mice as previously reported. This study demonstrates for the first time that invasive pressure and MRI derived volume measurements can be made simultaneously in mice.

Use of gated 13N-NH3 micro-PET to examine left ventricular function in rats

Myocardial perfusion gating techniques offer the possibility of measurement of left ventricular end-systolic (ESV) and end-diastolic volume (EDV) and left ventricular ejection fraction (LVEF) in clinical and preclinical trials. The aim of this study was to evaluate left ventricular volumes (LVV) and LVEF with 13N-NH3 in comparison with the reference 18F-FDG in different rat models. In this study, 18 male Wistar rats, 12 control rats and 6 rats with myocardial infarction (MI) were imaged with micro-PET. The ratswere scanned with gated 13N-NH3 and 18F-FDG sequentially for the assessment of LVV and LVEF. A validated three-dimensional segmentation algorithm was used to calculate LVV and LVEF. Mean LVEF measured with 13N-NH3 was 45.6±8.9 and 75.3±9.4%, mean ESV was 0.40±0.12 and 0.14±0.11 ml, and mean EDVwas 0.53±16 and 0.75±0.18 ml for MI and control rats, respectively. Moderate to good correlations were observed between values of 13N-NH3 and 18F-FDG for calculation of ESV [r=0.80, P<.0001, standard error of estimate (SEE)=0.10], EDV (r=0.63, P=.005, SEE=0.14) and LVEF (r=0.84, P<.0001, SEE=9.5). LVEF measured with 13N-NH3 was significantly lower in MI rats in comparison to measurement with 18F-FDG (45.6±8.9 vs 54.9±9.3 %; P=.04). Correlations were moderate to good for the assessment of ESV, EDV and LVEF between gated 13N-NH3 and 18F-FDG. LVEF was underestimated with gated 13N-NH3 in rats with myocardial infarction. In healthy rats, LV volumes and LVEF can be measured reproducibly with either approach.

Inter-study variability in CMR measurements of right ventricular volume, mass and ejection fraction in tetralogy of fallot: a prospective observational study

Background Cardiac MRI (CMR) is commonly used for serial monitoring of right ventricular (RV) size and function in patients with repaired tetralogy of Fallot (TOF). However, the inter-study variability of these measurements is not known, which hinders accurate interpretation of serial changes. In this study we prospectively assessed the inter-study variability of CMR measurements of RV size and function in TOF patients. Methods Patients with repaired TOF referred for a clinically indicated CMR examination at our institution were prospectively enrolled. ECG-gated steady-state free precession cine imaging of ventricular long- and short-axis planes was obtained on a 1.5 T scanner. Immediately after the conclusion of the examination, patients returned for a second study performed by a different technologist. Ventricular size and function data from both short-axis image sets were analyzed by a single observer and compared using Bland-Altman analysis with calculation of a repeatability coefficient (2SD of difference between studies), and intra-class correlation coefficient (ICC). Results

Left ventricular stroke volume measurement by impedance cardiography correlates with echocardiography in neonates

The aim of this study was to validate impedance cardiography (electrical velocimetry (EV)) as a continuous noninvasive cardiac output monitoring in neonates and infants. As the reference method, discontinuous transthoracic echocardiography (TTE) was used.

Accuracy of measurement of left ventricular volume and function in coronary heart disease with real-time threedimensional echocardiography

Objective To evaluate the accuracy of measurement of left ventricular(LV) volume and function in coronary heart disease(CHD) by real-time three-dimensional echocardiography(RT-3DE) using cardiac magnetic resonance imaging (CMRI).Methods LV end diastolic volume(EDV),LV end systolic volume(ESV) and LV ejection fraction(EF) were measured with RT-3DE in patients with CHD ( n =37) and in the control ( n =30).The results measured by RT 3DE were compared with those of CMRI.The diagnostic value of RT-3DE was evaluated using receiver operating characteristic(ROC) curve.Results Compared with that measured by CMRI,EDV,ESV and EF by RT 3DE( P ＞0.05) were almost similar as that in the control.Area under ROC curve of in EDV and ESV were 0.912 and 0.944 in the control.However,EDV determined by RT-3DE was smaller than that by CMRI( P ＜0.05) in CHD group.A difference (10.95 ± 31.26 ml) was existed in EDV between the two methods.ESV measured by RT-3DE was smaller than that calculated by CMRI( P ＞0.05) with a mean differance of (3.17 ± 16.42)ml in CHD group.EF by RT-3DE( P ＞0.05)was almost as same as that by CMRI in CHD group,with a mean difference of (1.54 ± 11.85)％.The area under ROC curve of EDV and ESV were 0.834 and 0.873 in CHD group and their diagnostic performance was moderate.Conclusions Measurment of LV volume and function by RT 3DE in control was more acurrate than that in CHD.In the cases of LV remodeling in patients with CHD,RT-3DE would underestimate the LV volume. Key words: Echocardiography,real time three-dimentional; Coronary disease; Ventricular functionleft; Cardiac volume; Magnetic resonance imaging

Core Lab Analysis of Baseline Echocardiographic Studies in the STICH Trial and Recommendation for Use of Echocardiography in Future Clinical Trials

The Surgical Treatment for Ischemic Heart Failure (STICH) randomized trial was designed to identify an optimal management strategy for patients with ischemic cardiomyopathy. Baseline echocardiographic examinations were required for all patients. The primary aim of this report is to describe the baseline STICH Echocardiography Core Laboratory data. The secondary aim is to provide recommendations regarding how echocardiography should be used in clinical practice and research on the basis of the experience gained from echocardiography in STICH. Between September 2002 and January 2006, 2,136 patients with ejection fractions (EFs) ≤ 35% and coronary artery disease amenable to coronary artery bypass grafting were enrolled. Echocardiography was acquired by 122 clinical enrolling sites, and measurements were performed by the Echocardiography Core Laboratory after a certification process for all clinical sites. Echocardiography was available for analysis in 2,006 patients (93.9%); 1,734 (86.4%) were men, and the mean age was 60.9 ± 9.5 years. The mean left ventricular end-systolic volume index, measureable in 72.8%, was 84.0 ± 30.9 mL/m(2), and the mean EF was 28.9 ± 8.3%, with 18.5% of patients having EFs > 35%. Single-plane measurements of left ventricular and left atrial volumes were similar to their volumes by biplane measurement (r= 0.97 and r= 0.92, respectively). Mitral regurgitation severity by visual assessment was associated with a wide range of effective regurgitant orifice area, while effective regurgitant orifice area ≥ 0.2 cm(2) indicated at least moderate mitral regurgitation by visual assessment. Deceleration time of mitral inflow velocity had a weak correlation with EF (r= 0.25) but was inversely related to estimated pulmonary artery systolic pressure (r= -0.49). In STICH patients with ischemic cardiomyopathy, Echocardiography Core Laboratory analysis of baseline echocardiographic findings demonstrated a wide spectrum of left ventricular shape, function, and hemodynamics, as well as the feasibility and limitations of obtaining essential echocardiographic measurements. It is critical that the use of echocardiographic parameters in clinical practice and research balance the strengths and weaknesses of the technique.

Availability of Semi-automatic Measurements of Left Ventricular Volume and Ejection Fraction by 2D and 3D Echocardiography

Availability of Semi-automatic Measurements of Left Ventricular Volume and Ejection Fraction by 2D and 3D Echocardiography

Cardiovascular magnetic resonance in systemic hypertension.

Systemic hypertension is a highly prevalent potentially modifiable cardiovascular risk factor. Imaging plays an important role in the diagnosis of underlying causes for hypertension, in assessing cardiovascular complications of hypertension, and in understanding the pathophysiology of the disease process. Cardiovascular magnetic resonance (CMR) provides accurate and reproducible measures of ventricular volumes, mass, function and haemodynamics as well as uniquely allowing tissue characterization of diffuse and focal fibrosis. In addition, CMR is well suited for exclusion of common secondary causes for hypertension. We review the current and emerging clinical and research applications of CMR in hypertension.

Significant Bias Associated With Left Ventricular Volume Measurements by MRI Compared to Echo (2D, 2D-Contrast and 3D)—A Systematic Review

Significant Bias Associated With Left Ventricular Volume Measurements by MRI Compared to Echo (2D, 2D-Contrast and 3D)—A Systematic Review

MR imaging correlates of white-matter pathology in a preterm baboon model

Cerebral white-matter (WM) abnormalities on magnetic resonance imaging (MRI) correlate with neurodevelopmental disability in infants born prematurely. Quantitative histological measures of WM and ventricular volumes correlated with qualitative MRI scores of WM volume loss and ventriculomegaly. Diffuse astrocytosis was associated with signal abnormality on T(2)-weighted imaging and higher apparent diffusion coefficient in WM. Loss of oligodendrocytes was associated with lower relative anisotropy characterized by higher radial diffusivity values. The relationship between histopathology and MRI abnormalities was more pronounced in animals in the 28 d model, equivalent to the term human infant. MRI reflects microstructural and anatomical abnormalities that are characteristic of WM injury in the preterm brain, and these changes are more evident on MRI at term-equivalent postmenstrual age. We assessed the histopathological correlates of MRI abnormalities in a baboon model of premature birth. Baboons were delivered at 125 d of gestation (dg, term ~185 dg) and maintained in an animal intensive care unit for 14 (n = 26) or 28 d (n = 17). Gestational control animals were delivered at 140 dg (n = 9) or 153 dg (n = 4). Cerebral WM in fixed brains was evaluated using MRI, diffusion tensor imaging (DTI), and histopathology.

Comparison of dual-source 64-slice adenosine stress CT perfusion with stress-gated SPECT-MPI for evaluation of left ventricular function and volumes

Evaluation of left ventricular (LV) volumes and ejection fraction (LVEF) represent important components of pharmacologic stress imaging with either myocardial CT perfusion (CTP) or gated single-photon emission CT (SPECT) myocardial perfusion imaging (SPECT-MPI). We compared measurements of left ventricular function and volumes obtained with CTP and SPECT-MPI. Forty-seven patients (mean age, 62 ± 11 years; male, n = 39) underwent stress CTP and SPECT-MPI. LVEF (in %), end-systolic volume (ESV; in mL), and end-diastolic volume (EDV; in mL) derived from stress CTP images were compared with SPECT-MPI. Stress CTP was in good agreement with SPECT-MPI for quantification of LVEF (r = 0.91), EDV (r = 0.75), and ESV (r = 0.83; all P < 0.001). The mean LVEF measured by stress CTP (66% ± 17%) was similar to SPECT-MPI (64% ± 15%). Similar values were also derived for mean EDV (123 ± 30 mL vs 120 ± 34 mL) and ESV (44 ± 28 mL vs 51 ± 34 mL) for CTP and SPECT-MPI, respectively. Good agreement was also shown between both techniques for the assessment of regional wall motion with identical wall motion scores in 95.3% of the segments (κ = 0.79). LVEF and LV volume parameters as determined by dual-source 64-slice adenosine stress CTP show a high correlation with values obtained with stress-gated SPECT-MPI.

Real Time Triplane Echocardiography in the Assessment of the Functional Area of Prosthetic Aortic Valves: Reliability and Feasibility

Our study is aimed at evaluating the feasibility and reliability of a simple method for the measurement of the functional area of prosthetic aortic valves (EOA). Three-dimensional echocardiography has proven accurate for left ventricular volume, stroke volume, and aortic valve area measurement. We studied the feasibility and reliability of real time simultaneous triplane echocardiography (RT3P) for assessing the EOA with a fast formula based on the principle of continuity equation, in which we replaced Doppler-derived stroke volume (SV) with SV directly measured with RT3P. EOA of prosthetic aortic valves were measured in 23 consecutive patients requiring periodical follow up. EOA was calculated using Doppler continuity equation (DCE) and the RT3P method by replacing Doppler-derived SV with SV measured with real time triplane echocardiography. We compared functional areas obtained with the two methods with the prosthetic area indicated in the manufacturer's specifications and with the mean transprosthetic gradient. Both methods had a good correlation with the area indicated by the manufacturer. RT3P revealed an inverse correlation between functional area and mean gradient that was better than DCE (P = 0.0359). Inter- and intraobserver variability was not different between the two methods. Execution time was significantly shorter for RT3P. RT3P is a simple method that can be performed quite rapidly, and can complement the overall assessment of prosthetic valve function. Further studies can confirm our technique.

Reproducibility of echocardiographic measurements of human fetal left ventricular volumes and ejection fractions using four-dimensional ultrasound with the spatio-temporal image correlation modality

Objectives To determine the reproducibility, both reliability and agreement, of measurements of fetal left ventricular parameters from volumes obtained by spatio-temporal image correlation (STIC) acquisition applying virtual organ computer-aided analysis (VOCAL) and Simpson's rule (method of discs). Furthermore the success rate of STIC acquisition was determined. Study design In 84 pregnancies between 20 and 34 weeks of gestation the fetal heart was scanned using the STIC modality. An optimal four-chamber view in end-diastole and end-systole was obtained. Left ventricular end-diastolic volume, left ventricular end-systolic volume, stroke volume and ejection fraction were determined. For calculations based on Simpson's rule only one plane was traced, whereas for VOCAL six planes were traced. To quantify the reliability intraclass correlation coefficients were calculated for both intra- and inter-observer measurements. Agreement of measurements was evaluated by Bland–Altman plots. Results The STIC volumes of 54 women (64%) were excluded from the study because of poor quality, leaving 30 volumes for further analysis. Intraclass correlation coefficients for intra-observer reliability for VOCAL and Simpson were 0.99 and 0.99 for left ventricular end-diastolic volume, 0.95 and 0.92 for left ventricular end-systolic volume, 0.98 and 0.97 for stroke volume, 0.76 and 0.77 for ejection fraction, respectively. Intraclass correlation coefficients for inter-observer reliability for VOCAL and Simpson were 0.97 and 0.86 for left ventricular end-diastolic volume, 0.97 and 0.86 for left ventricular end-systolic volume, 0.95 and 0.81 for stroke volume, 0.68 and 0.63 for ejection fraction, respectively. According to Bland–Altman plots, the mean percentage difference and 95% limits of intra- and inter-observer agreement for left ventricular stroke volume measurements using VOCAL were −0.2 (−25.1, 24.7)% and 2.8 (−34.2, 39.8)%, respectively. For left ventricular stroke volume measured with Simpson versus VOCAL the mean percentage difference and 95% limits of agreement were −1.8 (−22.1, 18.5)%. Conclusions 4D STIC enables reproducible measurements of left ventricular volumes. Reliability of the VOCAL mode is not essentially different from the single-plane method used in Simpson's rule. The large percentage of poor quality STIC volumes and the wide limits of inter-observer agreement would create obstacles for the clinical applicability of this technique.

Brain and ventricular volume in patients with syndromic and complex craniosynostosis

PurposeBrain abnormalities in patients with syndromic craniosynostosis can either be a direct result of the genetic defect or develop secondary to compression due to craniosynostosis, raised ICP or hydrocephalus. Today it is unknown whether children with syndromic craniosynostosis have normal brain volumes. The purpose of this study was to evaluate brain and ventricular volume measurements in patients with syndromic and complex craniosynostosis. This knowledge will improve our understanding of brain development and the origin of raised intracranial pressure in syndromic craniosynostosis.MethodsBrain and ventricular volumes were calculated from MRI scans of patients with craniosynostosis, 0.3 to 18.3 years of age. Brain volume was compared to age matched controls from the literature. All patient charts were reviewed to look for possible predictors of brain and ventricular volume.ResultsTotal brain volume in syndromic craniosynostosis equals that of normal controls, in the age range of 1 to 12 years. Brain growth occurred particularly in the first 5 years of age, after which it stabilized. Within the studied population, ventricular volume was significantly larger in Apert syndrome compared to all other syndromes and in patients with a Chiari I malformation.ConclusionsPatients with syndromic craniosynostosis have a normal total brain volume compared to normal controls. Increased ventricular volume is associated with Apert syndrome and Chiari I malformations, which is most commonly found in Crouzon syndrome. We advice screening of all patients with Apert and Crouzon syndrome for the development of enlarged ventricle volume and the presence of a Chiari I malformation.

Simultaneous Measurement of Left and Right Ventricular Volumes and Ejection Fraction During Dobutamine Stress Cardiovascular Magnetic Resonance

During cardiovascular stress, if right ventricular (RV) stroke volume exceeds left ventricular (LV) stroke volume, then a large volume of blood is displaced into the pulmonary circulation that may precipitate pulmonary edema. We sought to determine the metrics by which cardiovascular magnetic resonance (CMR) could measure simultaneous displacement of RV and LV stroke volumes during dobutamine stress. Thirteen healthy subjects (5 women) aged 53 ± 10 years without medical conditions and taking no medications underwent 2 CMR examinations at 1.5 T separated by 4 to 8 weeks in which RV and LV stroke volumes were determined during intravenous dobutamine and atropine infused to achieve 80% of the maximum predicted heart rate response for age. The RV and LV stroke volumes were highly correlated at each level of stress (rest: r = 0.98, P = 0.007; low stress: r = 0.87, P = 0.001; and peak stress: r = 0.88, P = 0.001), and the mean difference in SV at each level of stress (rest, low stress, and peak stress was 0 to 2 mL on examinations 1 and 2. Simultaneous change in right and left ventricular stroke volumes can be assessed in a highly reproducible manner throughout the course of dobutamine CMR stress administered to achieve 80% of maximum predicted heart rate response for age. This technology may help identify discrepancies in RV and LV stroke volumes during cardiovascular stress that are associated with the development of pulmonary edema.

A Pilot Study of Quantitative MRI Measurements of Ventricular Volume and Cortical Atrophy for the Differential Diagnosis of Normal Pressure Hydrocephalus

Current radiologic diagnosis of normal pressure hydrocephalus (NPH) requires a subjective judgment of whether lateral ventricular enlargement is disproportionate to cerebral atrophy based on visual inspection of brain images. We investigated whether quantitative measurements of lateral ventricular volume and total cortical thickness (a correlate of cerebral atrophy) could be used to more objectively distinguish NPH from normal controls (NC), Alzheimer's (AD), and Parkinson's disease (PD). Volumetric MRIs were obtained prospectively from patients with NPH (n = 5), PD (n = 5), and NC (5). Additional NC (n = 5) and AD patients (n = 10) from the ADNI cohort were examined. Although mean ventricular volume was significantly greater in the NPH group than all others, the range of values overlapped those of the AD group. Individuals with NPH could be better distinguished when ventricular volume and total cortical thickness were considered in combination. This pilot study suggests that volumetric MRI measurements hold promise for improving NPH differential diagnosis.