Semi-automatic tumour segmentation by selective navigation in a three-parameter volume, obtained by voxel-wise kinetic modelling of 11C-acetate

Positron emission tomography (PET) is increasingly used for delineation of tumour tissue in, for example, radiotherapy treatment planning. The most common method used is to outline volumes with a certain per cent uptake over background in a static image. However, PET data can also be collected dynamically and analysed by kinetic models, which potentially represent the underlying biology better. In the present study, a three-parameter kinetic model was used for voxel-wise evaluation of (11)C-acetate data of head/neck tumours. These parameters which represent the tumour blood volume, the uptake rate and the clearance rate of the tissue were derived for each voxel using a linear regression method and used for segmentation of active tumour tissue. This feasibility study shows that it is possible to segment images based on derived model parameters. There is, however, room for improvements concerning the PET data acquisition, noise reduction and the kinetic modelling. In conclusion, this early study indicates a strong potential of the method even though no 'true' tumour volume was available for validation.

Variation in organic matter and water color in Lake Mälaren during the past 70 years

Interest in long time series of organic matter data has recently increased due to concerns about the effects of global climate change on aquatic ecosystems. This study presents and evaluates unique time series of chemical oxygen demand (COD) and water color from Lake Malaren, Sweden, stretching almost seven decades (1935-2004). A negative linear trend was found in COD, but not in water color. The decrease was mainly due to installation of sewage works around 1970. Time series of COD and water color had cyclic pattern. It was strongest for COD, with 23 years periodicity. Similar periodicity observed in air temperature and precipitation in Sweden has been attributed to the North Atlantic Oscillation index and solar system orbit, suggesting that COD in Lake Mälaren is partly derived from algae. Discharge influenced water color more than COD, possibly because water color consists of colored substances brought into the lake from surrounding soils.

Rapid and easy semi-quantitative evaluation method for diacylglycerol and inositol-1,4,5-trisphosphate generation in orexin receptor signalling

AIM

Fluorescent protein-based indicators have enabled measurement of intracellular signals previously nearly inaccessible for studies. However, indicators showing intracellular translocation upon response suffer from serious limitations, especially the very time-consuming data collection. We therefore set out in this study to evaluate whether fixing and counting cells showing translocation could mend this issue.

METHODS

Altogether three different genetically encoded indicators for diacylglycerol and inositol-1,4,5-trisphosphate were transiently expressed in Chinese hamster ovary cells stably expressing human OX(1) orexin receptors. Upon stimulation with orexin-A, the cells were fixed with six different protocols.

RESULTS

Different protocols showed clear differences in their ability to preserve the indicator's localization (i.e. translocation after stimulus) and its fluorescence, and the best results for each indicator were obtained with a different protocol. The concentration-response data obtained with cell counting are mostly comparable to the real-time translocation and biochemical data.

CONCLUSION

The counting method, as used here, works at single time point and looses the single-cell-quantitative aspect. However, it also has some useful properties. First, it easily allows processing of a 100- to 1000-fold higher cell numbers than real-time imaging producing statistically consistent population-quantitative data much faster. Secondly, it does not require expensive real-time imaging equipment. Fluorescence in fixed cells can also be quantitated, though this analysis would be more time-consuming than cell counting. Thirdly, in addition to the quantitative data collection, the method could be applied for identifying responsive cells. This might be very useful in identification of e.g. orexin-responding neurones in a large population of non-responsive cells in primary cultures.

Who will become malnourished? A prospective study of factors associated with malnutrition in older persons living at home

OBJECTIVES

To describe the nutritional status of older persons living at home, to investigate factors of importance for nutritional status, and to describe possible relationships between nutritional status and health-related quality of life (HRQoL).

DESIGN

A longitudinal study using data from older persons born between 1916 and 1925. Data were collected at three occasions separated by four-year intervals.

SETTING

Data collection was carried out in the participants' own homes. An experimenter administered all tests and conducted the interviews.

PARTICIPANTS

A randomized selection from the Swedish Twin Register included 258 persons, all still living at home.

MEASUREMENTS

Nutritional status was assessed using the Mini Nutritional Assessment (MNA), cognitive function using the Mini-Mental State Examination (MMSE) and HRQoL using the Nottingham Health Profile (NHP). Questions covering physical, psychological and social factors that may have an impact on nutritional status were also posed.

RESULTS

Approximately 17% of participants were assessed as being at risk for malnutrition or as being malnourished. Cognitive impairment, reduced perceived health, recent hospital stay and receiving meals-on-wheels were factors associated with being at risk for malnutrition.

CONCLUSION

Being at risk for malnutrition is common in older persons living at home, and many factors related to frailty increase this risk in later life. Making use of knowledge of these factors when giving care to older persons may be important in preventing nutritional problems.

CHEK2*1100delC is not an important high-risk gene in families with hereditary prostate cancer in southern Sweden

OBJECTIVE

CHEK2*1100delC is a frame-shifting germ-line mutation which abolishes the function of cell-cycle-checkpoint kinase 2 (chk2) and hence impairs the cells' response to DNA damage. This variant occurs in 1% of the general Western population but has been reported to be more common among patients with breast and prostate cancer. The aim of this study was to investigate the significance of CHEK2*1100delC as a possible high-risk gene for hereditary prostate cancer in the population of southern Sweden.

MATERIAL AND METHODS

We screened for the CHEK2*1100delC variant in 419 men diagnosed with prostate cancer in southern Sweden, 145 of whom were sporadic cases that were divided into two subgroups depending on whether they were diagnosed before (n=64) or after (n=81) the age of 55 years. A further 126 men were classified as familial prostate cancer cases and 148 as hereditary prostate cancer cases. The control group consisted of 305 military conscripts aged 18 years (range 18-21 years).

RESULTS

The CHEK2*1100delC variant was found in 1.2% of the cases (sporadic: 0.7%; familial: 1.6%; hereditary: 1.4%) and in 1.0% of the controls.

CONCLUSION

The CHEK2 1100delC mutation is not a clinically important high-risk gene for hereditary prostate cancer susceptibility in the population of southern Sweden.

Reproducibility of hepatic triglyceride content assessment in normals using localized magnetic resonance spectroscopy

AIM

To investigate the reproducibility of measurements of hepatic triglyceride content (HTGC) in subjects with normal HTGC using localized (1)H-magnetic resonance spectroscopy ((1)H-MRS) and a clinical 1.5T scanner.

METHODS

The (1)H-MRS acquisition was performed with a common protocol using the whole-body coil and no respiratory triggering. An upper limit of normal HTGC of 5.56% was used. Duplicate measurements, including subject repositioning, were acquired from 23 subjects, 19 of whom had a normal HTGC.

RESULTS

The mean coefficient of variation (CV) from the duplicate measurements was 14.8% (20.5% before exclusion of a subject who was considered to be an outlier). Mean CVs of subgroups below and above the 1% HTGC limit were 19.8 and 7.0 respectively.

CONCLUSIONS

The mean CV calculated in subjects with HTGC in the normal range was found to be higher than CVs of wide range HTGC groups reported in the literature. It is concluded that the reproducibility of HTGC measurements using (1)H-MRS depends on the HTGC range. These findings are of importance in reproducibility studies and in estimations of required study group sizes.

Familial antithrombin III deficiency as pathogenesis of deep venous thrombosis

A family including 18 members with decreased antithrombin III (AT III), measured with both a biological and an immunochemical method, is described. The pattern found on crossed immunoelectrophoresis, using heparin in the agarose in the first run, was normal, though the peaks were low. This suggests decreased synthesis of a normal protein in the affected members. AT III deficiency occurred in both the paternal and the maternal branch, of the above 18 persons had had at least one thromboembolic episode. Some of the episodes had been precipitated by the presence or occurrence of some predisposing event or circumstance. This suggests the possible occurrence of a gene making some of the maternal family members more susceptible to certain trigger factors, such as surgery, infection, pregnancy, and the puerperium. The mode of inheritance filled all the criteria for autosomal dominant transmission. Prophylactic treatment, preferably oral anticoagulants and/or dextran, is recommended for all persons with a low AT III concentration in any situation known to increase the predisposition to thrombosis. The effect of heparin in these patients is impaired since the heparin co-factor, which is identical with AT III, is lowered.

A family with thromboembolic disease associated with deficient fibrinolytic activity in vessel wall

Defective fibrinolytic activity is often a contributory factor in deep venous thrombosis. A family with a high incidence of venous thrombosis in association with such a defect is presented. Of 13 family members who had had thrombosis, 12 showed a defective capacity to release fibrinolytic activity from vessel wall after venous occlusion and/or infusion of DDAVP, a vasopressin derivative. The fibrinolytic activator activity of the vessel wall was normal in all cases. This seems to be the first family in which there is evidence of an inherited abnormal fibrinolytic activity.

Comparison of streptokinase with heparin: late results in the treatment of deep venous thrombosis

Nineteen cases were reinvestigated 8-14 years after treatment with SK or heparin. Judging from personal interviews, foot volumometry and phlebography, treatment with SK appears to be more preferable since it was less often followed by late severe postthrombotic changes.

Venous saturation slab causes overestimation of stenosis length in two-dimensional time-of-flight magnetic resonance angiography

BACKGROUND

The use of downstream saturation slabs in two-dimensional time-of-flight magnetic resonance angiography (2D TOF MRA) of the arterial system eliminates signal from regions with countercurrent flow, as seen in veins, but possibly also beyond arterial stenoses because of flow turbulence.

PURPOSE

To investigate the contribution of a downstream saturation slab to signal intensity (SI) loss beyond stenoses at 2D TOF MRA.

MATERIAL AND METHODS

2D TOF MRA was performed on a bifurcation phantom with a tight stenosis at 1.5T during pulsatile flow. Qualitative and quantitative evaluations of stenosis delineation were performed with different echo times (TE) (3.7 or 7.0 ms), spatial resolution (1 x 1 x 1 or 1 x 1 x 5 mm(3)), and with or without a downstream saturation slab. For reference, a high-resolution contrast-enhanced sequence without flow was obtained.

RESULTS

The downstream saturation slab caused severe signal loss immediately distal to the stenosis, causing overestimation of stenosis length. This region corresponded with a region of poststenotic flow jet, where turbulence is expected. With increase in TE, there was some increased SI loss at the level of maximum stenosis. A lower spatial resolution resulted in overall poorer delineation of the stenosis.

CONCLUSION

Using clinically relevant sequence parameters, the use of a downstream saturation slab at 2D TOF MRA was found to be a major contributor to signal loss in stenotic regions, which can result in an overestimation of stenosis length.

Visceral adipose tissue, adiponectin levels and insulin resistance are related to atherosclerosis as assessed by whole-body magnetic resonance angiography in an elderly population

OBJECTIVE

The principal aim of this study was to determine whether the amount of visceral adipose tissue (VAT) is more related than subcutaneous adipose tissue (SAT) to atherosclerosis assessed by whole-body MRA (WBMRA). A further objective was to investigate whether traditional risk factors, inflammation, or adipokines could explain the hypothesized relationship between VAT and atherosclerosis.

METHODS

Men and women aged 70 were recruited from the general population into the Prospective Investigation of The Vasculature in Uppsala Seniors (PIVUS) and 306 of them underwent WBMRA in a clinical 1.5-T scanner. The arterial tree was assessed for degree of stenosis or occlusion and a total atherosclerotic score (TAS) was established. Information on risk factors and BMI and on SAT and VAT, segmented on an axial MR scan was collected. Adiponectin, leptin, and high sensitive C-reactive protein (hsCRP) were measured in serum. HOMA index was used as a marker of insulin resistance.

RESULTS

VAT was related to TAS independently of gender, total obesity (BMI), amount of SAT, hsCRP and also to the traditional risk factors included in the Framingham risk score (FRS) in an elderly population. Adiponectin or the HOMA insulin resistance, but not leptin or VAT, together with FRS was significantly related to TAS in a multiple censored regression model.

CONCLUSION

Adiponectin attenuated the relationship between VAT and TAS, suggesting that adiponectin and insulin resistance is an important link between visceral adiposity and atherosclerosis.

Assessment of lipids in skeletal muscle by high-resolution spectroscopic imaging using fat as the internal standard: comparison with water referenced spectroscopy

The main purpose of the study was to compare proton (1H) single-voxel MR spectroscopy (MRS) with high-spatial-resolution spectroscopic imaging (MRSI) to determine the lipid content in human skeletal muscle. Unsuppressed water line was used as a concentration reference in the processing of single-voxel spectra. The spectrum from yellow bone marrow with a 100% fat content and probe with the vegetable oil served as internal and external reference for high-spatial-resolution MRSI, respectively. Very good correlation was found between lipid concentrations measured by water referenced single-voxel MRS and high-spatial-resolution MRSI with yellow bone marrow as the internal standard. Excellent correlation was found between total lipid concentrations estimated by high-spatial-resolution MRSI with vegetable oil as the external fat standard and yellow bone marrow as the internal reference. From comparison of single-voxel MRS and MRSI approaches, it follows that relaxation correction of the reference water and methylene fat line is inevitable in processing the standard single-voxel spectra. The high-resolution MRSI approach is recommended to avoid the problem of relaxation corrections and enables using vegetable oil as the external fat standard.

Multiple phospholipase activation by OX(1) orexin/hypocretin receptors

We investigated coupling of OX(1) receptors to phospholipase activation and diacylglycerol generation in Chinese hamster ovary (CHO) cells using both biochemical and fluorescence "real-time" methods. The results indicate that at lowest orexin-A concentrations (highest potency), diacylglycerol generated results from phospholipase D activity. At 10-100-fold higher orexin-A concentrations, phospholipase C is activated, likely hydrolyzing phosphatidylinositol (PI) or phosphatidylinositol monophosphate (PIP) but not phosphatidylinositol bisphosphate (PIP(2)). At further 7-fold higher orexin-A concentrations, PIP(2) is hydrolyzed, releasing both diacylglycerol and inositol-1,4,5-trisphosphate. Thus, OX(1) orexin receptors connect to multiple phospholipase activities, apparently composed of at least one phospholipase D and two different phospholipase C activities. At low agonist concentrations, diacylglycerol and phosphatidic acid are the preferred products, and interestingly, it seems that even the primarily activated phospholipase C mainly works to increase diacylglycerol and not inositol-1,4,5-trisphosphate.

A high-density SNP linkage scan with 142 combined subtype ADHD sib pairs identifies linkage regions on chromosomes 9 and 16

As part of the International Multi-centre ADHD Genetics project we completed an affected sibling pair study of 142 narrowly defined Diagnostic and Statistical Manual of Mental Disorders, fourth edition combined type attention deficit hyperactivity disorder (ADHD) proband-sibling pairs. No linkage was observed on the most established ADHD-linked genomic regions of 5p and 17p. We found suggestive linkage signals on chromosomes 9 and 16, respectively, with the highest multipoint nonparametric linkage signal on chromosome 16q23 at 99 cM (log of the odds, LOD=3.1) overlapping data published from the previous UCLA (University of California, Los Angeles) (LOD>1, approximately 95 cM) and Dutch (LOD>1, approximately 100 cM) studies. The second highest peak in this study was on chromosome 9q22 at 90 cM (LOD=2.13); both the previous UCLA and German studies also found some evidence of linkage at almost the same location (UCLA LOD=1.45 at 93 cM; German LOD=0.68 at 100 cM). The overlap of these two main peaks with previous findings suggests that loci linked to ADHD may lie within these regions. Meta-analysis or reanalysis of the raw data of all the available ADHD linkage scan data may help to clarify whether these represent true linked loci.

Ankle brachial index <0.9 underestimates the prevalence of peripheral artery occlusive disease assessed with whole-body magnetic resonance angiography in the elderly

BACKGROUND

Whole-body magnetic resonance angiography (WBMRA) permits noninvasive vascular assessment, which can be utilized in epidemiological studies.

PURPOSE

To assess the relation between a low ankle brachial index (ABI) and high-grade stenoses in the pelvic and leg arteries in the elderly.

MATERIAL AND METHODS

WBMRA was performed in a population sample of 306 subjects aged 70 years. The arteries below the aortic bifurcation were graded after the most severe stenosis according to one of three grades: 0-49% stenosis, 50-99% stenosis, or occlusion. ABI was calculated for each side.

RESULTS

There were assessable WBMRA and ABI examinations in 268 (right side), 265 (left side), and 258 cases (both sides). At least one > or =50% stenosis was found in 19% (right side), 23% (left side), and 28% (on at least one side) of the cases. The corresponding prevalences for ABI <0.9 were 4.5%, 4.2%, and 6.6%. An ABI cut-off value of 0.9 resulted in a sensitivity, specificity, and positive and negative predictive value of 20%, 99%, 83%, and 84% on the right side, and 15%, 99%, 82%, and 80% on the left side, respectively, for the presence of a > or =50% stenosis in the pelvic or leg arteries.

CONCLUSION

An ABI <0.9 underestimates the prevalence of peripheral arterial occlusive disease in the general elderly population.

The risk of myocardial infarction and sudden cardiac death amongst snuff users with or without a previous history of smoking

OBJECTIVES

To investigate the risk of a first myocardial infarction (MI) and sudden cardiac death (SCD) amongst male snuff users.

DESIGN

We used a prospective incident case-referent study design nested in the population-based Västerbotten Intervention Program and the Northern Sweden MONICA study.

SUBJECTS

Tobacco habits and cardiovascular risk factors were assessed at baseline screening and compared in 525 male MI cases (including 93 SCD cases) and 1798 matched referents.

RESULTS

Myocardial infarction occurred on average 4 years and 2 months after the baseline screening. No increased risk for MI was found amongst snuff users without a previous history of smoking compared with nontobacco users after adjustments for body mass index, leisure time physical activity, educational level and cholesterol level (OR 0.82; 95% CI, 0.46-1.43). For snuff users with a previous history of smoking, the adjusted OR was 1.25 (95% CI, 0.80-1.96). Significantly increased risk for MI was found in current smokers with or without current snuff use. For SCD cases with survival time<24 h, the adjusted OR for snuff users without previous history of smoking was 1.18 (95% CI, 0.38-3.70) and for cases with survival time<1 h the OR was 0.38 (95% CI, 0.08-1.89).

CONCLUSIONS

We found no increased risk for MI amongst snuff users without a previous history of smoking. Amongst snuff users with a previous history of smoking, the tendency towards an increased risk for MI may reflect the residual risk from former smoking. This study does not support the hypothesis that the risk for SCD is increased amongst snuff users.

Patient acceptance of a novel electronic auto-injector device to administer recombinant human growth hormone: results from an open-label, user survey of everyday use

OBJECTIVE

To measure the user acceptance of a electronic auto-injector device (easypod) for recombinant human growth hormone (r-hGH) administration.

STUDY DESIGN AND METHODS

This was an open-label, uncontrolled study in which participants (n = 61) were trained to use the device to administer subcutaneous recombinant human growth hormone (r-hGH). Participants' opinions on the device were recorded by questionnaire and/or telephone interview during training and after 15 and 60 days of use. Opinions on the device were also collected from nurses or physicians who trained the participants in device use.

RESULTS

After 60 days, 98% (54/55) of responders reported a 'good' or 'very good' overall impression of the device. The pre-programmed dose feature, skin sensor, on-screen instructions, display of remaining dose, confirmation of injected dose and automatic needle attachment were identified by the majority of participants as 'very useful'. Participants were reported to have easily understood the injection process, and 87% (48/55) expressed a preference to continue use of the device. The device had a good safety profile, and no adverse events were reported during the study or follow-up periods.

CONCLUSIONS

Participants had a good overall impression of the device and the majority expressed a preference to continue its use. The combination of features offered by the device make it user-friendly, and such ease of use may facilitate greater adherence to treatment, in turn improving therapy outcomes.

Automated and reproducible segmentation of visceral and subcutaneous adipose tissue from abdominal MRI

OBJECTIVES

(1) To develop a fully automated algorithm for segmentation of visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT), excluding intermuscular adipose tissue (IMAT) and bone marrow (BM), from axial abdominal magnetic resonance imaging (MRI) data. (2) To evaluate the algorithm accuracy and total method reproducibility using a semi-automatically segmented reference and data from repeated measurements.

BACKGROUND

MRI is a widely used in adipose tissue (AT) assessment. Manual analysis of MRI data is time consuming and biased by the operator. Automated analysis spares resources and increase reproducibility. Fully automated algorithms have been presented. However, reproducibility analysis has not been performed nor has methods for exclusion of IMAT and BM been presented.

METHODS

In total, 49 data sets from 31 subjects were acquired using a clinical 1.5 T MRI scanner. Thirteen data sets were used in the derivation of the automated algorithm and 36 were used in the validation. Common image analysis tools such as thresholding, morphological operations and geometrical models were used to segment VAT and SAT. Accuracy was assessed using a semi-automatically created reference. Reproducibility was assessed from repeated measurements.

RESULTS

Resulting AT volumes from the automated analysis and the reference were not found to differ significantly (2.0+/-14% and 0.84+/-2.7%, given as mean+/-s.d., for VAT and SAT, respectively). The automated analysis of the repeated measurements data significantly increased the reproducibility of the VAT measurements. One athletic subject with very small amounts of AT was considered to be an outlier.

CONCLUSIONS

An automated method for segmentation of VAT and SAT and exclusion of IMAT and BM from abdominal MRI data has been reported. The accuracy and reproducibility of the method has also been demonstrated using a semi-automatically segmented reference and analysis of repeated acquisitions. The accuracy of the method is limited in lean subjects.

Changes in multi-segmented body movements and EMG activity while standing on firm and foam support surfaces

Postural control ensures stability during both static posture and locomotion by initiating corrective adjustments in body movement. This is particularly important when the conditions of the support surface change. We investigated the effects of standing on a compliant foam surface using 12 normal subjects (mean age 26 years) in terms of: linear movements at the head, shoulder, hip and knee; EMG activity of the tibialis anterior and gastrocnemius muscles and torques towards the support surface. As subjects repeated the trials with eyes open or closed, we were also able to determine the effects of vision on multi-segmented body movements during standing upon different support surface conditions. As expected, EMG activity, torque variance values and body movements at all measured positions increased significantly when standing on foam compared with the firm surface. Linear knee and hip movements increased more, relative to shoulder and head movements while standing on foam. Vision stabilized the head and shoulder movements more than hip and knee movements while standing on foam support surface. Moreover, vision significantly reduced the tibialis anterior EMG activity and torque variance during the trials involving foam. In conclusion, the foam support surface increased corrective muscle and torque activity, and changed the firm-surface multi-segmented body movement pattern. Vision improved the ability of postural control to handle compliant surface conditions. Several essential features of postural control have been found from recording movements from multiple points on the body, synchronized with recording torque and EMG.

Correlation of femoral artery flow velocity waveform with ipsilateral iliac artery stenoses assessed with magnetic resonance imaging

BACKGROUND

Magnetic resonance (MR) permits quantitative flow velocity measurements that could be used to detect changes in the curve profile downstream of a high-grade stenosis.

PURPOSE

To assess whether MR flow measurements can be used to detect iliac artery stenoses.

MATERIAL AND METHODS

Contrast-enhanced magnetic resonance angiography (MRA) and quantitative flow measurements in the lower aorta and proximal femoral arteries were performed in 29 patients with suspected iliac artery stenoses. Stenoses were graded into five degrees: 0%, 1-49%, 50-74%, 75-99%, and 100% diameter reduction. The femoral artery waveforms were evaluated qualitatively by two independent reviewers regarding peak systolic velocity (PSV), aortofemoral difference in time-to-peak (DeltaTTP), systolic acceleration (SA), curve-shape index (CSI), and the presence of an early diastolic flow reversal. The correlation between these parameters and the degree of stenosis was assessed.

RESULTS

A significant correlation with degree of stenosis was observed for the qualitative flow waveform evaluations, with a high degree of interobserver agreement (kappa = 0.84). A significant correlation was also found between degree of stenosis and PSV, DeltaTTP, SA, CSI, and presence of diastolic flow reversal. The flow velocity pattern, however, remained unchanged, both qualitatively and quantitatively, up to a stenosis degree of at least 75%.

CONCLUSION

Iliac artery stenoses cause femoral artery flow waveform changes that can be detected with MRI, but only at high-grade levels.

The exactness of left ventricular segmentation in cine magnetic resonance imaging and its impact on systolic function values

PURPOSE

To evaluate the impact of exactness of the segmentation of the left ventricle (LV), using cine magnetic resonance imaging (MRI).

MATERIAL AND METHODS

Steady-state free-precession cine MRI was performed on 100 randomly selected subjects. Myocardial borders were outlined on short-axis images using three methods: method 1 was computer assisted, excluding papillary muscles from the left ventricular mass (LVM); method 2 was similar but included papillary muscles; and method 3 was manually traced including papillary muscles. LV end-systolic (ES) and end-diastolic (ED) masses and volumes, ejection fraction (EF), stroke volume (SV), and cardiac output (CO) were calculated from these measurements. The difference between the ES and ED LVM was used to estimate the exactness of the methods.

RESULTS

Method 3 was the most exact, and method 1 was the least exact. The three methods generated differing EF, SV, and CO measurements. With an ES-ED LVM difference exceeding 20 g, the mean SV measurement error was 8.8+/-3.6 ml.

CONCLUSION

Manual tracing proved more exact than computer-assisted quantification. Exactness had an impact on EF, SV, and CO measurements, and the ES-ED LVM difference can be used to identify assessments that would benefit from more exact segmentation.