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Dive into the research topics where Mark B.M. Hofman is active.

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Featured researches published by Mark B.M. Hofman.


Journal of the American College of Cardiology | 2003

Delayed contrast-enhanced magnetic resonance imaging for the prediction of regional functional improvement after acute myocardial infarction.

Aernout M. Beek; Harald P. Kühl; Olga Bondarenko; Jos W. R. Twisk; Mark B.M. Hofman; Willem G. van Dockum; Cees A. Visser; Albert C. van Rossum

OBJECTIVES We evaluated whether delayed contrast-enhanced magnetic resonance imaging (DCE-MRI) using an extracellular contrast agent could predict improvement of dysfunctional but viable myocardium after acute reperfused myocardial infarction (MI). BACKGROUND The transmural extent of hyperenhancement at DCE-MRI has been related to improvement of function in reperfused MI. However, evidence is still limited, and earlier reports have produced conflicting results regarding the significance of contrast patterns after infarction. METHODS Thirty patients (mean age 59 +/- 11 years, 27 males) underwent cine MRI and DCE-MRI 7 +/- 3 days after a first reperfused acute MI and follow-up cine MRI at 13 +/- 3 weeks. Segmental wall thickening and segmental extent of hyperenhancement were scored in 1,689 segments. RESULTS Of 500 dysfunctional segments, 273 (55%) improved at follow-up. There was no difference in likelihood of improvement or complete functional recovery between segments with 0% and 1% to 25% hyperenhancement. The likelihood of improvement of segments without hyperenhancement was 2.9, 14.3, and 20 times higher than that of segments with 26% to 50%, 51% to 75%, and >75% hyperenhancement, respectively (p < 0.001). The likelihood of complete functional recovery of segments without hyperenhancement was 3.8, 11.1, and 50 times higher than that of segments with 26% to 50%, 51% to 75%, and >75% hyperenhancement, respectively (p < 0.001). CONCLUSIONS In patients with recent reperfused MI, functional improvement of stunned myocardium is predicted by DCE-MRI.


Journal of the American College of Cardiology | 2003

Myocardial viability in chronic ischemic heart disease: Comparison of contrast-enhanced magnetic resonance imaging with 18F-fluorodeoxyglucose positron emission tomography

Harald P. Kühl; Aernout M. Beek; Arno P. van der Weerdt; Mark B.M. Hofman; Cees A. Visser; Adriaan A. Lammertsma; Nicole Heussen; Frans C. Visser; Albert C. van Rossum

OBJECTIVES We sought to compare contrast-enhanced magnetic resonance imaging (ceMRI) with nuclear metabolic imaging for the assessment of myocardial viability in patients with chronic ischemic heart disease and left ventricular (LV) dysfunction. BACKGROUND Contrast-enhanced MRI has been shown to identify scar tissue in ischemically damaged myocardium. METHODS Twenty-six patients with chronic coronary artery disease and LV dysfunction (mean ejection fraction 31 +/- 11%) underwent (18)F-fluorodeoxyglucose (FDG) positron emission tomography (PET), technetium-99m tetrofosmin single-photon emission computed tomography (SPECT), and ceMRI. In a 17-segment model, the segmental extent of hyperenhancement (SEH) by ceMRI, defined as the relative amount of contrast-enhanced tissue per myocardial segment, was compared with segmental FDG and tetrofosmin uptake by PET and SPECT. RESULTS In severely dysfunctional segments (n = 165), SEH was 9 +/- 14%, 33 +/- 25% (p < 0.05), and 80 +/- 23% (p < 0.05) in segments with normal metabolism/perfusion, metabolism/perfusion mismatch, and matched defects, respectively. Segmental glucose uptake by PET was inversely correlated to SEH (r = -0.86, p < 0.001). By receiver operator characteristic curve analysis, the area under the curve was 0.95 for the differentiation between viable and non-viable segments. At a cutoff value of 37%, SEH optimally differentiated viable from non-viable segments defined by PET. Using this threshold, the sensitivity and specificity of ceMRI to detect non-viable myocardium as defined by PET were 96% and 84%, respectively. CONCLUSIONS Contrast-enhanced MRI allows assessment of myocardial viability with a high accuracy, compared with FDG-PET, in patients with chronic ischemic heart disease and LV dysfunction.


Circulation | 2005

Early Onset and Progression of Left Ventricular Remodeling After Alcohol Septal Ablation in Hypertrophic Obstructive Cardiomyopathy

Willem G. van Dockum; Aernout M. Beek; Folkert J. ten Cate; Jurriën M. ten Berg; Olga Bondarenko; Marco J.W. Götte; Jos W. R. Twisk; Mark B.M. Hofman; Cees A. Visser; Albert C. van Rossum

Background—Alcohol septal ablation (ASA) reduces left ventricular outflow tract (LVOT) pressure gradient in patients with hypertrophic obstructive cardiomyopathy (HOCM), which leads to left ventricular remodeling. We sought to describe the early to midterm changes and modulating factors of the remodeling process using cardiac MRI (CMR). Methods and Results—CMR was performed at baseline and 1 and 6 months after ASA in 29 patients with HOCM (age 52±16 years). Contrast-enhanced CMR showed no infarct-related hyperenhancement outside the target septal area. Septal mass decreased from 75±23 g at baseline to 68±22 and 58±19 g (P<0.001) at 1- and 6-month follow-up, respectively. Remote, nonseptal mass decreased from 141±41 to 132±40 and 111±27 g (P<0.001), respectively. Analysis of temporal trends revealed that septal mass reduction was positively associated with contrast-enhanced infarct size and transmural or left-sided septal infarct location at both 1 and 6 months. Remote mass reduction was associated with infarct location at 6 months but not with contrast-enhanced infarct size. By linear regression analysis, percentage remote mass reduction correlated significantly with LVOT gradient reduction at 6-month follow-up (P=0.03). Conclusions—Left ventricular remodeling after ASA occurs early and progresses on midterm follow-up, modulated by CMR infarct size and location. Remote mass reduction is associated with infarct location and correlates with reduction of the LVOT pressure gradient. Thus, myocardial hypertrophy in HOCM is, at least in part, afterload dependent and reversible and is not exclusively caused by the genetic disorder.


Magnetic Resonance in Medicine | 2001

Quantitative differentiation between BOLD models in fMRI

F.G.C. Hoogenraad; Petra J. W. Pouwels; Mark B.M. Hofman; Jürgen R. Reichenbach; Michiel Sprenger; E. M. Haacke

Several gradient‐echo fMRI blood oxygenation level‐dependent (BOLD) effects are described in the literature: extravascular spin dephasing around capillaries and veins, intravascular phase changes, and transverse relaxation changes of blood. This work considers a series of tissue compartmentalized models incorporating each of these effects, and tries to determine the model which is most consistent with the data. To isolate the different tissue contributions, a series of multi‐echo inversion recovery (IR) fMRI scans were performed. Visual stimulation experiments were performed at 1.5 T, one interleaved six‐echo and two IR six‐echo EPI scans (the latter to suppress gray matter (GM) and cerebrospinal fluid (CSF)). The tissue and vascular composition of activated areas was analyzed using independent spin‐echo IR MRI experiments and MR venography, respectively. This information was used to fit the multi‐echo fMRI data to the BOLD models. The activated areas almost always included a venous vessel visible on the venogram and consisted of GM and CSF. The fMRI signal changes were best described by extravascular dephasing effects in both GM and CSF around a venous vessel, in combination with intravascular effects. The role of spin dephasing around capillaries in GM appears to be insignificant. Magn Reson Med 45:233–246, 2001.


Journal of the American College of Cardiology | 2003

Clinical study: cardiac imagingMyocardial viability inchronic ischemic heart disease: Comparison of contrast-enhanced magnetic resonance imaging with 18F-fluorodeoxyglucose positron emission tomography

Harald P. Kühl; Aernout M. Beek; Arno P. van der Weerdt; Mark B.M. Hofman; Cees A. Visser; Adriaan A. Lammertsma; Nicole Heussen; Frans C. Visser; Albert C. van Rossum

OBJECTIVES We sought to compare contrast-enhanced magnetic resonance imaging (ceMRI) with nuclear metabolic imaging for the assessment of myocardial viability in patients with chronic ischemic heart disease and left ventricular (LV) dysfunction. BACKGROUND Contrast-enhanced MRI has been shown to identify scar tissue in ischemically damaged myocardium. METHODS Twenty-six patients with chronic coronary artery disease and LV dysfunction (mean ejection fraction 31 +/- 11%) underwent (18)F-fluorodeoxyglucose (FDG) positron emission tomography (PET), technetium-99m tetrofosmin single-photon emission computed tomography (SPECT), and ceMRI. In a 17-segment model, the segmental extent of hyperenhancement (SEH) by ceMRI, defined as the relative amount of contrast-enhanced tissue per myocardial segment, was compared with segmental FDG and tetrofosmin uptake by PET and SPECT. RESULTS In severely dysfunctional segments (n = 165), SEH was 9 +/- 14%, 33 +/- 25% (p < 0.05), and 80 +/- 23% (p < 0.05) in segments with normal metabolism/perfusion, metabolism/perfusion mismatch, and matched defects, respectively. Segmental glucose uptake by PET was inversely correlated to SEH (r = -0.86, p < 0.001). By receiver operator characteristic curve analysis, the area under the curve was 0.95 for the differentiation between viable and non-viable segments. At a cutoff value of 37%, SEH optimally differentiated viable from non-viable segments defined by PET. Using this threshold, the sensitivity and specificity of ceMRI to detect non-viable myocardium as defined by PET were 96% and 84%, respectively. CONCLUSIONS Contrast-enhanced MRI allows assessment of myocardial viability with a high accuracy, compared with FDG-PET, in patients with chronic ischemic heart disease and LV dysfunction.


Radiology | 2009

Assessment of Microvascular Obstruction and Prediction of Short-term Remodeling after Acute Myocardial Infarction: Cardiac MR Imaging Study

Robin Nijveldt; Mark B.M. Hofman; Alexander Hirsch; Aernout M. Beek; Victor A. Umans; Paul R. Algra; Jan J. Piek; Albert C. van Rossum

PURPOSE To evaluate which cardiac magnetic resonance (MR) imaging technique for detection of microvascular obstruction (MVO) best predicts left ventricular (LV) remodeling after acute myocardial infarction (MI). MATERIALS AND METHODS This study had local ethics committee approval; all patients gave written informed consent. Sixty-three patients with first acute MI, treated with primary stent placement and optimal medical therapy, underwent cine MR imaging at 4-7 days and at 4 months after MI. Presence of MVO was qualitatively evaluated at baseline by using three techniques: (a) a single-shot saturation-recovery gradient-echo first-pass perfusion sequence (early hypoenhancement), mean time, 1.09 minutes +/- 0.07 (standard deviation) after contrast material administration; (b) a three-dimensional segmented saturation-recovery gradient-echo sequence (intermediate hypoenhancement), mean time, 2.17 minutes +/- 0.26; and (c) a two-dimensional segmented inversion-recovery gradient-echo late gadolinium enhancement sequence (late hypoenhancement), mean time, 13.32 minutes +/- 1.26. Contrast-to-noise ratios (CNRs) were calculated from the signal-to-noise ratios of the infarcted myocardium and MVO areas. Univariable linear regression analysis was used to identify the predictive value of each MR imaging technique. RESULTS Early hypoenhancement was detected in 44 (70%) of 63 patients; intermediate hypoenhancement, in 39 (62%); and late hypoenhancement, in 37 (59%). Late hypoenhancement was the strongest predictor of change in LV end-diastolic and end-systolic volumes over time (beta = 14.3, r = 0.40, P = .001 and beta = 11.3, r = 0.44, P < .001, respectively), whereas intermediate and late hypoenhancement had comparable predictive values of change in LV ejection fraction (beta = -3.1, r = -0.29, P = .02 and beta = -2.8, r = -0.27, P = .04, respectively). CNR corrected for spatial resolution was significantly superior for late enhancement compared with the other sequences (P < .001). CONCLUSION By using cardiac MR imaging, late hypoenhancement is the best prognostic marker of LV remodeling, with highest CNR between the infarcted myocardium and MVO regions.


American Heart Journal | 1995

Semiquantitation of regional myocardial blood flow in normal human subjects by first-pass magnetic resonance imaging

Jan T. Keijer; Albert C. van Rossum; Machiel J. van Eenige; Arend J.P. Karreman; Mark B.M. Hofman; Jaap Valk; Cees A. Visser

The purpose of this study was to investigate the feasibility of first-pass MR imaging for measurement of regional myocardial blood flow in human beings. The first pass of the contrast agent Gd-DTPA through the myocardium was imaged in 12 normal volunteers with an ECG-gated Turbo-Flash sequence. The MTT of the contrast agent through the myocardium after a bolus injection was derived from curves of SI versus time. The bolus was injected through an intravenous catheter, which was advanced to the central venous position (preferably the right atrium). To investigate myocardial input function, different bolus concentrations and catheter positions were compared. It is concluded that first-pass MR imaging is feasible in human subjects when a central injection of 0.03 mmol/kg of Gd-DTPA is applied. MTT values were similar throughout the myocardium of normal subjects at rest, reflecting normal perfusion. Absolute values of MTT were related to the myocardial input.


Journal of Magnetic Resonance Imaging | 1999

Sub-millimeter fMRI at 1.5 Tesla: correlation of high resolution with low resolution measurements.

Frank G.C. Hoogenraad; Mark B.M. Hofman; Petra J. W. Pouwels; Jürgen R. Reichenbach; Serge A.R.B. Rombouts; E. Mark Haacke

Functional magnetic resonance imaging of the visual cortex with an in‐plane resolution of 0.4 × 0.4 mm2 was performed using a simple visual stimulus resulting in clear maps of activation. A collapsing filter was used to compare these high‐resolution images with low‐resolution images collected during the same session. A good correspondence between the high‐ and low‐resolution functional maps was found with respect to the center of localization of activation. However, only 20% of the size of activated areas in the low‐resolution experiment was observed at high resolution, which was partly caused by the difference in signal‐to‐noise ratio. The high‐resolution images produce signal changes much higher than the low‐resolution images due to reduced partial volume effects. Additionally, the high‐resolution functional maps were compared with detailed anatomical and venous information. The activated areas were predominantly observed at venous vessels within the sulci with a diameter on the order of the pixel size. J. Magn. Reson. Imaging 1999;9:475–482.


Magnetic Resonance Imaging | 2000

High-resolution segmented EPI in a motor task fMRI study

Frank G.C. Hoogenraad; Petra J. W. Pouwels; Mark B.M. Hofman; Serge A.R.B. Rombouts; C Lavini; Martin O. Leach; E.M Haacke

A high-resolution gradient echo, multi-slice segmented echo planar imaging method was used for functional MRI (fMRI) using a motor task at 1.5 Tesla. Functional images with an in-plane resolution of 1 mm and slice thickness of 4 mm were obtained with good white-gray matter contrast. The multi-shot approach, combined with a short total readout period of 82 ms, limits blurring effects for short T(2)(*) tissues (such as gray matter), assuring truly high-resolution images. In all subjects, motor functions were clearly depicted in the contralateral central sulcus over several slices and sometimes activation was detected in the supplementary motor area and/or ipsilateral central sulcus. The average signal change of 11+/-3% was much higher than in standard low-resolution fMRI EPI experiments, as a result of larger relative blood fractions.


American Heart Journal | 1995

Protocol for two-dimensional magnetic resonance coronary angiography studied in three-dimensional magnetic resonance data sets.

Johannes C. Post; Albert C. van Rossum; Mark B.M. Hofman; Jaap Valk; Cees A. Visser

The purpose of this study was to develop a standardized method of 2D MRA of the proximal 50 mm of the major epicardial coronary arteries. Therefore the efficacy of fixed imaging planes (transverse, coronal, sagittal, 30-degree RAO equivalent, and 60-degree LAO equivalent) in imaging coronary arteries was compared to that of oblique planes defined by the operator on a previously obtained image. 3D data sets obtained by a respiratory-gated 3D MRA method in eight patients with a mean age of 57 years were studied by multiplanar reformatting. Efficacy of planes was expressed as an IOE. Fixed transverse imaging planes proved to be equally efficacious as operator-defined planes in imaging the left main (IOE 2.2 +/- 1.0 vs 2.2 +/- 0.9, p = NS) and LAD (IOE 6.0 +/- 1.9 vs 8.2 +/- 2.0, p = NS). Operator-defined planes were superior to fixed imaging planes in imaging the RCA (IOE 6.3 +/- 1.2 vs 3.5 +/- 1.2, p < 0.001) and the LCx (IOE 6.2 +/- 2.3 vs 4.8 < 2.3, p < 0.05). On the basis of these results, a standardized 2D MRA protocol for the proximal coronary arteries was proposed. Pitfalls in interpretation of coronary MRA images were discussed.

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Albert C. van Rossum

VU University Medical Center

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Aernout M. Beek

VU University Medical Center

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Cees A. Visser

VU University Medical Center

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Willem G. van Dockum

VU University Medical Center

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Jaap Valk

VU University Amsterdam

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Jos W. R. Twisk

VU University Medical Center

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Robin Nijveldt

VU University Medical Center

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Marco J.W. Götte

VU University Medical Center

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Folkert J. ten Cate

Erasmus University Rotterdam

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