Biomedical subjects

Kirsi Lauerma

Publications and source records attributed to Kirsi Lauerma.

13 recordsLinked to original sources

PubMed2006

Eight-row multidetector computed tomography coronary angiography evaluation of significant coronary artery disease in patients with severe aortic valve stenosis.

BACKGROUND: The aim of this study was to evaluate whether 8-row multidetector computed tomography coronary angiography (MDCT-CA) could replace invasive conventional coronary angiography (CCA) in patients with acquired severe aortic valve stenosis (AS). Coronary artery disease (CAD) diagnosis should be obtained with a noninvasive method in patients with AS undergoing valvular replacement. We evaluated the diagnostic accuracy of MDCT-CA in detecting high-grade (> or =50%) stenoses in the main coronary arteries in patients with AS. METHODS: Twenty-three patients with acquired severe AS underwent both CCA and MDCT-CA. We calculated the total and volumetric calcium scores and evaluated the image quality of each coronary segment as assessable or nonassessable for stenosis. The images of the arteries were evaluated for the occurrence of artifacts and the presence of high-grade stenoses (> or =50%) by visual estimation and comparison with that of CCA. RESULTS: Of the 322 segments screened 224 were assessable for stenosis. Heavy calcium load rendered 37 (38%) of the 98 coronary segments nonassessable. Compared to CCA, MDCT-CA had a sensitivity of 63%, a specificity of 96%, a positive predictive value of 52%, and a negative predictive value of 98% for > or =50% stenoses in the main coronary arteries. CONCLUSIONS: Eight-row MDCT-CA revealed a low sensitivity in detecting significant coronary artery disease in patients with acquired severe AS. High calcium burden decreased visualization of the lumen and complicated most often a correct assessment. In this patient group, CCA should still remain the primary pre-surgical test to rule out coronary lesions requiring revascularization.

Aged↗

PubMed2006

Noninvasive analysis of coronary artery disease with combination of MDCT and functional MRI.

RATIONALE AND OBJECTIVES: We evaluated the diagnostic accuracy of an eight-row multidetector computed tomography coronary angiography (MDCT-CA) in detecting high-grade (>50%) stenoses in the three main coronary arteries in patients with coronary artery disease (CAD). Side branches were excluded. We correlated magnetic resonance imaging (MRI) findings of the myocardium with MDCT-CA of the coronary arteries. MATERIALS AND METHODS: Fourteen CAD patients underwent conventional coronary angiography (CCA), MDCT-CA, and MRI. We determined the calcium burden with non-enhanced MDCT scan. Then MDCT-CA was performed after intravenous contrast injection during a single breathhold. The left ventricular (LV) MR cine imaging was assessed at rest and perfusion defects were observed during pharmacologic stress after contrast administration. Delayed contrast-enhanced MRI was performed to picture infarctions. RESULTS: MDCT-CA had sensitivity 82%, specificity 94%, positive predictive value 79%, and negative predictive value 95% of stenoses of more than 50% in the main coronary arteries when compared with CCA. LV wall dysfunction, perfusion defects, and infarctions were detected in 50%-78% of sectors assigned to calcifications or stenoses, but also in sectors supplied by normally perfused coronary arteries. CONCLUSIONS: CCA and MDCT-CA revealed comparable results in evaluating stenotic lesions above 50% in the main subepicardial coronary branches. There were no significant correlations between the degree of stenosis or calcification at MDCT-CA and the MR findings, but the combined information of MDCT-CA and MRI showed the variability of myocardial changes in regions perfused by significantly stenosed, calcified, and normal main coronary arteries.

Adult↗

PubMed2006

Magnetocardiographic assessment of healed myocardial infarction.

BACKGROUND: We evaluated the capability of multichannel magnetocardiography (MCG) to detect healed myocardial infarction (MI). METHODS: Multichannel MCG over frontal chest was recorded at rest in 21 patients with healed MI, detected by cine- and contrast-enhanced magnetic resonance imaging, and in 26 healthy controls. Of the 21 MI patients, 11 had non-Q wave and 10 Q wave MIs. QRS, ST-segment, T wave and ST-T wave integrals, ST-segment and T wave amplitudes, and QRS and ST-T wave magnetic field map orientations were measured. RESULTS: The MCG repolarization indexes, such as ST segment and ST-T wave integrals, separated the MI group from the controls (ST-T wave integral -1.4 +/- 5.3 vs 1.5 +/- 4.7 pTs, P = 0.034). The abnormalities were more distinct in the Q wave-MI than in the non-Q wave MI subgroup. In the latter, however, a trend similar to the Q wave MI group was found. The relation of QRS area to ST segment and T wave integral improved the detection of healed MIs compared to the ST-T wave indexes alone (QRS-ST-T discordance 14 +/- 10 vs 5.0 +/- 7.1 pTs, P = 0.003). When comparing the MI group to the controls, the orientation of the magnetic field maps differed in the ST-T wave maps (163 +/- 119 degrees vs 58 +/- 17 degrees, P < 0.001) but not in the QRS maps (111 +/- 95 degrees vs 106 +/-93 degrees, P = 0.646). CONCLUSIONS: The MCG repolarization variables can detect healed MI. These ST-T wave abnormalities are more pronounced in patients with Q wave MI than in patients with non-Q wave MIs. Relating the signals of depolarization and repolarization phases improves the detection of healed MI. Repolarization abnormalities are common in healed MI and thus should not always be interpreted as present ongoing ischemia.

Aged↗

PubMed2005

Cine MR imaging of myocardial contractile impairment in patients with hypertrophic cardiomyopathy attributable to Asp175Asn mutation in the alpha-tropomyosin gene.

PURPOSE: To prospectively investigate the relationship between myocardial contractile impairment and left ventricular (LV) hypertrophy measured at cardiac magnetic resonance (MR) imaging in patients with hypertrophic cardiomyopathy (HCM) caused by the substitution of aspartic acid 175 with asparagine (ie, Asp175Asn mutation) in the alpha-tropomyosin gene (TPM1). MATERIALS AND METHODS: The study protocol was approved by the hospital ethics committee, and all subjects gave written informed consent. LV mass, maximal LV wall thickness, and myocardial fractional thickening during systole were measured at cine MR imaging in 24 subjects (11 male, 13 female; mean age, 42 years; age range, 17-68 years) with the Asp175Asn mutation in TPM1 and in 17 healthy volunteers (eight men, nine women; mean age, 38 years; age range, 23-60 years). The proportion of hypokinetic LV segments was calculated as the number of LV segments with fractional thickening of less than 30% divided by the total number of segments measured. Anthropometric and biochemical correlates of LV hypertrophy were determined. Univariate and multiple linear regression analyses were used to investigate the association of the proportion of hypokinetic segments and other correlates of LV hypertrophy with LV mass and maximal wall thickness. RESULTS: The proportion of hypokinetic segments was higher in patients with HCM than in control subjects (37% +/- 20 [standard deviation] vs 12% +/- 12, P < .001). In stepwise multiple regression analysis, the proportion of hypokinetic segments accounted for 42% (P < .001); the LV end-diastolic volume, for 24% (P = .003); and male sex, for 10% (P = .014) of the variability in LV mass in patients with HCM. The proportion of hypokinetic LV segments, which accounted for 48% of the variability in LV maximal wall thickness (P < .001), was the only variable significantly associated with maximal wall thickness. CONCLUSION: The extent of myocardial contractile impairment is strongly and independently related to LV mass and maximal wall thickness in patients with HCM attributable to the Asp175Asn mutation in TPM1.

Adult↗

PubMed2005

Familial hypercholesterolemia patients treated with statins at no increased risk for intracranial vascular lesions despite increased cholesterol burden and extracranial atherosclerosis.

BACKGROUND AND PURPOSE: To correlate known vascular disease risk factors and the signs of extracranial and intracranial changes of vascular origin in young patients with heterozygous familial hypercholesterolemia (FH). METHODS: 39 DNA test-verified heterozygous FH North Karelian patients (FH-NK), aged 6 to 48, 28 of them treated with statins, and 25 healthy controls underwent brain magnetic resonance imaging (MRI) and carotid ultrasound. RESULTS: Common carotid intima-media thickness was significantly greater in the patients (P=0.005). MR angiography showed no pathological changes, other than 1 incidental aneurysm. The number and size of white matter hyperintensities on T2-weighted MR images, considered as markers of microvascular alterations, did not differ between patients and controls. CONCLUSIONS: FH-NK patients treated with statins seem to be at no increased risk for brain infarcts or other brain lesions of vascular origin when younger than age 50.

Adolescent↗

PubMed2005

Correction of motion artifacts from cardiac cine magnetic resonance images.

RATIONALE AND OBJECTIVES: An image registration method was developed to automatically correct motion artifacts, mostly from breathing, from cardiac cine magnetic resonance (MR) images. MATERIALS AND METHODS: The location of each slice in an image stack was optimized by maximizing a similarity measure of the slice with another image slice stack. The optimization was performed iteratively and both image stacks were corrected simultaneously. Two procedures to optimize the similarity were tested: standard gradient optimization and stochastic optimization in which one slice is chosen randomly from the image stacks and its location is optimized. In this work, cine short- and long-axis images were used. In addition to visual inspection results from real data, the performance of the algorithm was evaluated quantitatively by simulating the movements in four real MR data sets. The mean error and standard deviation were defined for 50 simulated movements as each slice was randomly displaced. The error rate, defined as the percentage of non-satisfactory registration results, was evaluated. The paired t-test was used to evaluate the statistical difference between the tested optimization methods. RESULTS: The algorithm developed was successfully applied to correct motion artifacts from real and simulated data. The results, where typical motion artifacts were simulated, indicated an error rate of about 3%. Subvoxel registration accuracy was also achieved. When different optimization methods were compared, the registration accuracy of the stochastic approach proved to be superior to the standard gradient technique (P < 10(-9)). CONCLUSIONS: The novel method was capable of robustly and accurately correcting motion artifacts from cardiac cine MR images.

Adult↗

PubMed2005

Spatial repolarization abnormalities in old myocardial infarction.

Conventional electrocardiogram criteria for myocardial infarction (MI) rely on QRS features, but ST-T segment is also affected. We recorded body surface potential mapping in 24 patients with prior MI and in 24 controls. T-wave maximum amplitude and QRS and ST-T integrals were automatically determined. Old MI was verified by magnetic resonance imaging. ST-T integral and T-wave maximum amplitude outperformed QRS integral in detecting MI, with area under receiver operating characteristic curve of 94%, 95%, and 83%, respectively. ST-T integral performed better in non-Q-wave than Q-wave MI, with area under receiver operating characteristic curve of 97% and 92%, respectively. QRS integral correlated negatively with ST-T integral in patients with MI (r = -0.58, P < .001) and positively in controls (r = 0.45, P < .001). In conclusion, ST-T integral proved equal to QRS integral in old MI detection. Inclusion of ventricular repolarization phase and development of electrocardiographic analysis over larger chest area may improve the QRS-based diagnosis of old myocardial infarction.

Adult↗

PubMed2004

Cardiac involvement in Mulibrey nanism: characterization with magnetic resonance imaging.

Mulibrey nanism (MUL) is an autosomal recessive disorder that is enriched in the Finnish population. Variable degrees of pericardial and myocardial involvement can lead to heart failure and premature death. The purpose of this study was using magnetic resonance imaging (MRI) to assess structural and functional abnormalities of the MUL cardiopathy in all four cardiac chambers as well as in the pericardium. Thirty-one patients with MUL (mean age 27, range 15-50 years) and 16 controls (mean age 31, range 19-45 years) were examined with a Siemens Vision 1.5-T imager. Ten patients had undergone pericardiectomies to relieve symptoms of constrictive pericarditis. In surgery performed 0.5-25 years before MRI, the removed pericardium was found to be thickened and consisting of scarlike fibrosis. Turbo spin echo images were obtained for assessment of pericardial thickness, and breath hold left ventricular (LV) short axis and four-chamber cine images were obtained for the volumetric data. In MRI, pericardial thickness was normal (under 3.4 mm) in all patients with MUL. In the 10 pericardiectomized patients, the remnants of the pericardium were of normal thickness as well. The LV septum (p = 0.01) and posterior wall (p<0.001) were hypertrophied and end-diastolic volumes of both ventricles (p<0.05) were reduced in all patients. The LV systolic function was preserved. The volume chance during the first third of diastole (p = 0.030), the absolute peak filling rate (p = 0.047), and the time to peak rate of LV diastolic filling (p = 0.030) indicated restrictive LV diastolic filling. The right ventricular ejection fraction and contraction of both atria were reduced.

Adolescent↗

PubMed2004

Temporal analysis of the depolarization wave of healed myocardial infarction in body surface potential mapping.

BACKGROUND: We studied the ability of different time segments of the depolarization wave recorded with body surface potential mapping (BSPM) to detect and localize myocardial infarction (MI). METHODS: BSPM was recorded in 24 patients with remote MI and in 24 healthy controls. Cine and contrast-enhanced magnetic resonance imaging (MRI) was used as a reference method. Patients were grouped according to anatomical location of their MI. The QRS complex was divided into six temporally equal segments, for which time integrals were calculated. RESULTS: The time segments of the QRS complex showed different MI detection capability depending on MI location. For anterior infarction the second segment of the QRS complex was the best in MI detection and the optimal area was on the right inferior quadrant of the thorax (time integral average -1.5 +/- 1.8 mVms patients, 1.0 +/- 1.6 mVms controls, P = 0.002). For lateral infarction the first segment of the QRS complex performed best and the optimal area for MI detection was the left fourth intercostal area (time integral average 1.8 +/- 1.0 mVms patients, 0.7 +/- 0.5 mVms controls, P = 0.024). For inferior and posterior MI the mid-phases of the QRS complex were the best and the optimal area was the mid-inferior area of the thorax (time integral average -6.2 +/- 8.3 mVms patients, 3.3 +/- 4.3 mVms controls, P = 0.002; -9.1 +/- 6.1 mVms patients, 0.6 +/- 7.1 mVms controls, P = 0.001, respectively). CONCLUSIONS: Time segment analysis of the depolarization wave offers potential for improving the detection and localization of healed MI.

Aged↗

PubMed2003

A 3-D model-based registration approach for the PET, MR and MCG cardiac data fusion.

In this paper, a new approach is presented for the assessment of a 3-D anatomical and functional model of the heart including structural information from magnetic resonance imaging (MRI) and functional information from positron emission tomography (PET) and magnetocardiography (MCG). The method uses model-based co-registration of MR and PET images and marker-based registration for MRI and MCG. Model-based segmentation of MR anatomical images results in an individualized 3-D biventricular model of the heart including functional parameters from PET and MCG in an easily interpretable 3-D form.

Aged↗

PubMed2003

Wall motion and perfusion analysis of transmyocardial laser revascularization.

OBJECTIVE: Transmyocardial laser revascularization (TMLR) creates channels in the myocardium. The aim of the treatment is to relieve angina in patients with end-stage coronary artery disease. We studied the effect of TMLR on myocardial function and perfusion with the combination of cine magnetic resonance imaging (MRI) and thallium scintigraphy. DESIGN: Eight patients with severe triple-vessel coronary artery disease were studied with MRI and thallium scintigraphy before and 6 months after laser treatment. RESULTS: TMLR did not improve global left ventricular (LV) function or myocardial perfusion. However, systolic wall thickening deprived in segments with fixed perfusion defects in 6 months and laser treatment prevented this deprivation (p = 0.03). In addition single photon emission computed tomography (SPECT) imaging indicated that TMLR prevented conversion of reversible into fixed defects. CONCLUSION: In severe, progressing coronary artery disease TMLR does not improve global LV function or myocardial perfusion, but it preserves systolic wall thickening in fixed defects (scar). It also prevents changes from ischemic myocardial regions to scar.

Aged↗

PubMed2003

First-pass MR imaging in the assessment of perfusion impairment in patients with hypertrophic cardiomyopathy and the Asp175Asn mutation of the alpha-tropomyosin gene.

PURPOSE: To assess first-pass magnetic resonance (MR) imaging in the evaluation of perfusion impairment in a genetically homogeneous population of patients with hypertrophic cardiomyopathy (HCM) and the Asp175Asn mutation of the alpha-tropomyosin gene and to evaluate the association between hypertrophy and perfusion. MATERIALS AND METHODS: Rest-stress first-pass MR imaging with gadopentetate dimeglumine was performed in 17 patients with HCM and the Asp175Asn substitution in the alpha-tropomyosin gene and in five control subjects. Global and segmental first-pass reserve index (FPR) measurements were derived from signal intensity versus time curves. Left ventricular (LV) wall thickness and LV mass index were measured on cine MR images. The Mann-Whitney test was used to evaluate the difference in FPR between the patient group and the control group. The Spearman correlation was used to evaluate the association between LV hypertrophy and FPR. RESULTS: Global FPR was significantly lower in the patients with HCM than in the control subjects (1.12 +/- 0.35 vs 1.80 +/- 0.58, P =.015). In patients with HCM, maximal LV wall thickness and LV mass index correlated negatively with global FPR (r = -0.723, P =.001 and r = -0.598, P =.011, respectively). At the regional level, segmental FPR correlated inversely with LV wall thickness (r = -0.389; P <.001) in patients with HCM. CONCLUSION: First-pass MR imaging facilitates global and regional evaluation of perfusion impairment in patients with HCM. The severity of perfusion impairment is associated with the degree of LV hypertrophy.

Adenosine↗

PubMed2003

Cardiac adrenergic activity is associated with left ventricular hypertrophy in genetically homogeneous subjects with hypertrophic cardiomyopathy.

UNLABELLED: Hypertrophic cardiomyopathy (HCM) is a genetic disease caused by mutations in genes encoding sarcomeric proteins. However, other genetic and possibly also environmental factors modify the phenotypic expression of left ventricular (LV) hypertrophy. The present study investigated whether cardiac adrenergic activity affects the severity of LV hypertrophy in genetically identical patients with HCM. METHODS: The study population consisted of 21 patients with HCM caused by the Asp175Asn substitution of the alpha-tropomyosin gene (TPM1-Asp175Asn) and 9 healthy volunteers. LV mass and segmental wall thickness were measured with MRI. Presynaptic cardiac adrenergic activity was measured with (123)I-metaiodobenzylguanidine (MIBG) SPECT. Global and segmental washouts of (123)I-MIBG were calculated. RESULTS: Global myocardial (123)I-MIBG washout was faster in patients with TPM1-Asp175Asn than in healthy volunteers (50% +/- 9% vs. 37% +/- 8%, P = 0.001). In linear regression analysis, global (123)I-MIBG washout was associated with the LV mass index and LV maximal wall thickness index in HCM patients (r = 0.512, P = 0.018, and r = 0.478, P = 0.028, respectively). The mean (123)I-MIBG washout was higher in LV segments >/= 15 mm thick than in LV segments < 15 mm thick (56 +/- 10 vs. 49% +/- 10%, P = 0.002). CONCLUSION: In patients with HCM sharing the same causal gene defect, the degree of LV hypertrophy is related to (123)I-MIBG washout, suggesting that cardiac adrenergic activity modifies phenotypic expression in HCM.

3-Iodobenzylguanidine↗