Quantification of Myocardial Blood Flow by Machine Learning Analysis of Modified Dual Bolus MRI Examination.

Contrast-enhanced magnetic resonance imaging (MRI) is a promising method for estimating myocardial blood flow (MBF). However, it is often affected by noise from imaging artefacts, such as dark rim artefact obscuring relevant features. Machine learning enables extracting important features from such noisy data and is increasingly applied in areas where traditional approaches are limited. In this study, we investigate the capacity of machine learning, particularly support vector machines (SVM) and random forests (RF), for estimating MBF from tissue impulse response signal in an animal model. Domestic pigs (n = 5) were subjected to contrast enhanced first pass MRI (MRI-FP) and the impulse response at different regions of the myocardium (n = 24/pig) were evaluated at rest (n = 120) and stress (n = 96). Reference MBF was then measured using positron emission tomography (PET). Since the impulse response may include artefacts, classification models based on SVM and RF were developed to discriminate noisy signal. In addition, regression models based on SVM, RF and linear regression (for comparison) were developed for estimating MBF from the impulse response at rest and stress. The classification and regression models were trained on data from 4 pigs (n = 168) and tested on 1 pig (n = 48). Models based on SVM and RF outperformed linear regression, with higher correlation (R SVM 2 = 0.81, R RF 2 = 0.74, R linear_regression 2 = 0.60; ρSVM = 0.76, ρRF = 0.76, ρlinear_regression = 0.71) and lower error (RMSESVM = 0.67 mL/g/min, RMSERF = 0.77 mL/g/min, RMSElinear_regression = 0.96 mL/g/min) for predicting MBF from MRI impulse response signal. Classifier based on SVM was optimal for detecting impulse response signals with artefacts (accuracy = 92%). Modified dual bolus MRI signal, combined with machine learning, has potential for accurately estimating MBF at rest and stress states, even from signals with dark rim artefacts. This could provide a protocol for reliable and easy estimation of MBF, although further research is needed to clinically validate the approach.

Magnetic resonance imaging characteristics in patients with histopathologically proven fibrous dysplasia-a systematic review.

OBJECTIVE: To examine the demographics, lesion location, and characteristic magnetic resonance imaging (MRI) findings in patients with histopathologically proven fibrous dysplasia (FD). MATERIALS AND METHODS: A systematic literature search of the MRI findings in patients with histologically proven FD was performed. Altogether, 76 articles with 136 patients were evaluated. RESULTS: The mean age of the patients was 35.0 + - 18.5 years (range 1 month-75 years). Fifty-eight of the cases were females, 51 males, and in 27 gender was not defined. The most common locations were craniofacial (n = 55 (40%)), long bones (n = 31 (23%)), and spine (n = 24 (18%)). The monostotic form of FD was the most common. Signal intensities (SI) on T1-weighted images were predominantly hypointense (n = 46 (37%)). The SI was highly variable on T2-weighted images with hyperintensity being most common (n = 22 (18%)). Contrast enhancement was found in 75 (55%) FD patients. Secondary aneurysmal bone cysts (ABCs) and malignant transformation in patients without prior radiotherapy was found in some patients. CONCLUSION: Current knowledge of the MRI findings in patients with FD is based mainly on case reports. SI in patients with FD is variable and contrast enhancement is common. FD may explain etiology of spinal bone tumor in some patients. FD with malignant transformation should be considered also in patients without prior radiotherapy. Further studies are needed to clarify if FD displays specific characteristics allowing it to be distinguished from other bone tumors.

Quantification of porcine myocardial perfusion with modified dual bolus MRI - a prospective study with a PET reference.

BACKGROUND: The reliable quantification of myocardial blood flow (MBF) with MRI, necessitates the correction of errors in arterial input function (AIF) caused by the T1 saturation effect. The aim of this study was to compare MBF determined by a traditional dual bolus method against a modified dual bolus approach and to evaluate both methods against PET in a porcine model of myocardial ischemia. METHODS: Local myocardial ischemia was induced in five pigs, which were subsequently examined with contrast enhanced MRI (gadoteric acid) and PET (O-15 water). In the determination of MBF, the initial high concentration AIF was corrected using the ratio of low and high contrast AIF areas, normalized according to the corresponding heart rates. MBF was determined from the MRI, during stress and at rest, using the dual bolus and the modified dual bolus methods in 24 segments of the myocardium (total of 240 segments, five pigs in stress and rest). Due to image artifacts and technical problems 53% of the segments had to be rejected from further analyses. These two estimates were later compared against respective rest and stress PET-based MBF measurements. RESULTS: Values of MBF were determined for 112/240 regions. Correlations for MBF between the modified dual bolus method and PET was rs = 0.84, and between the traditional dual bolus method and PET rs = 0.79. The intraclass correlation was very good (ICC = 0.85) between the modified dual bolus method and PET, but poor between the traditional dual bolus method and PET (ICC = 0.07). CONCLUSIONS: The modified dual bolus method showed a better agreement with PET than the traditional dual bolus method. The modified dual bolus method was found to be more reliable than the traditional dual bolus method, especially when there was variation in the heart rate. However, the difference between the MBF values estimated with either of the two MRI-based dual-bolus methods and those estimated with the gold-standard PET method were statistically significant.

CMR derived left ventricular septal convexity in carriers of the hypertrophic cardiomyopathy-causing MYBPC3-Q1061X mutation.

This manuscript has not been published before and is not currently being considered for publication elsewhere. Increased septal convexity of left ventricle has been described in subjects with hypertrophic cardiomyopathy (HCM) -causing mutations without left ventricular hypertrophy (LVH). Our objective was to study septal convexity by cardiac magnetic resonance (CMR) in subjects with the Finnish founder mutation Q1016X in the myosin-binding protein C gene (MYBPC3). Septal convexity was measured in end-diastolic 4-chamber CMR image in 67 study subjects (47 subjects with the MYBPC3-Q1061X mutation and 20 healthy relatives without the mutation). Septal convexity was significantly increased in subjects with the MYBPC3-Q1061X mutation and LVH (n = 32) compared to controls (11.4 ± 4.3 vs 2.7 ± 3.2 mm, P < 0.001). In mutation carriers without LVH, there was a trend for increased septal convexity compared to controls (4.9 ± 2.5 vs 2.7 ± 3.2 mm, P = 0.074). When indexed for BSA, septal convexity in mutation carriers without LVH was 2.8 ± 1.4 mm/m2 and 1.5 ± 1.6 mm/m2 in controls (P = 0.036). In all mutation carriers, septal convexity correlated significantly with body surface area, age, maximal LV wall thickness, LV mass, and late gadolinium enhancement. Subjects with the MYBPC3-Q10961X mutation have increased septal convexity irrespective of the presence of LVH. Septal convexity appears to reflect septal remodeling, and could be useful in recognizing LVH negative mutation carriers.

Novel electrocardiographic features in carriers of hypertrophic cardiomyopathy causing sarcomeric mutations.

OBJECTIVES: The sensitivity and specificity of the conventional 12-lead ECG to identify carriers of hypertrophic cardiomyopathy (HCM) - causing mutations without left ventricular hypertrophy (LVH) has been limited. We assessed the ability of novel electrocardiographic parameters to improve the detection of HCM mutation carriers. METHODS: We studied 140 carriers (G+) of the TPM1-Asp175Asn or MYBPC3-Gln1061X pathogenic variants for HCM: The G+/LVH+ group (n = 98) consisted of mutation carriers with LVH and the G+/LVH- group (n = 42) without LVH. The control group consisted of 30 subjects. The standard 12-lead ECG was comprehensively analyzed and two novel ECG variables were introduced: RV1RV3 and septal remodeling. A subset of 65 individuals underwent cardiac magnetic resonance imaging and 2D strain echocardiography. RESULTS: Conventional major ECG criteria were sensitive (90%) and specific (97%) in identifying G+/LVH+ subjects. RV1RV3 and septal remodeling were more prevalent in the G+/LVH- subjects compared to the control group (33% vs 3%, p = 0.005 and 45% vs 3%, p < 0.001, respectively). The combination of RV1RV3 and Q waves and repolarization abnormalities (QR) differentiated between the G+/LVH- subjects and the control group with a sensitivity of 52% and specificity of 97%. The combination of septal remodeling and QR differentiated between G+/LVH- subjects and the control group with a sensitivity of 64% and specificity of 97%. CONCLUSIONS: The novel ECG-parameters RV1RV3 and septal remodeling were effective in identifying G+/LVH- subjects and could be useful in the diagnostics of new suspected HCM patients and in the screening and follow-up of HCM families.

Effects of knee flexion and extension on the tibial tuberosity-trochlear groove (TT-TG) distance in adolescents.

BACKGROUND: Measurement of the tibial tubercle-trochlear groove (TT-TG) distance is used to assess patellofemoral instability and rotation. Since patellofemoral instability and acute patellar dislocation are common among adolescents, it is important to clarify the relationship between TT-TG distance and various flexion and extension angles in asymptomatic children. The purpose of the present study was to determine how knee flexion and extension influence TT-TG-distance values measured using 3D imaging in an anatomic axial plane among asymptomatic adolescents. METHODS: We performed magnetic resonance imaging (MRI) of 26 knees in 13 adolescents (8 boys and 5 girls) of 11-17 years of age, with no known patellofemoral disorders. Imaging was performed with 3.0 T MRI with the knee at four separate angles of flexion between 0° and 30°. Measurements were made by two independent blinded raters. RESULTS: The mean TT-TG distance in millimetres was 11.1-0.29 × the angle in degrees. TT-TG distance decreased with greater flexion, showing a mean decrease of 0.29 mm (SD, 0.04) per degree of increased flexion (p < 0.001). We found significant inter-observer (Pearson's r = 0.636, p = 0.03) and intra-observer (Pearson's r = 0.792, p ≤ 0.001) correlations. TT-TG values were not significantly correlated with age, length, weight, or body mass index. The rate of TT-TG change (change between consecutive TT-TG values/change between consecutive angles) was significantly negatively correlated with length (p = 0.014), weight (p = 0.004), and body mass index (p = 0.025). CONCLUSIONS: Our data revealed that TT-TG distance assessed in the anatomic axial plane decreased with greater flexion in adolescent. Moreover, this effect of knee angle was stronger in smaller subjects. These findings support the need for a standardized protocol for TT-TG distance measurement in adolescents.

Fibrosis and wall thickness affect ventricular repolarization dynamics in hypertrophic cardiomyopathy.

BACKGROUND: Hypertrophic cardiomyopathy (HCM) is characterized by ventricular repolarization abnormalities and risk of ventricular arrhythmias. Our aim was to study the association between the phenotype and ventricular repolarization dynamics in HCM patients. METHODS: HCM patients with either the MYBPC3-Q1061X or TPM1-D175N mutation (n = 46) and control subjects without mutation and hypertrophy (n = 35) were studied with 24-hr ambulatory ECG recordings by measuring time intervals of rate-adapted QT (QTe), maximal QT, and T-wave apex to wave end (TPE) intervals and the QTe/RR slope. Findings were correlated to specified echocardiographic and cardiac magnetic resonance imaging (CMRI) findings. RESULTS: Rate-adapted QTe interval was progressively longer in HCM patients with decreasing heart rates compared to control subjects (p = 0.020). The degree of hypertrophy correlated with measured QTe values. HCM patients with maximal wall thickness higher than the mean (20.6 mm) had longer maximum QTe and median TPE intervals compared to control subjects and HCM patients with milder hypertrophy (p < 0.001 and p = 0.014, respectively). HCM patients with late gadolinium enhancement (LGE) on CMRI had steeper QTe/RR slopes compared to HCM patients without LGE and control subjects (p = 0.044 and p = 0.001, respectively). LGE was an independent predictor of QTe/RR slope (p = 0.023, B = 0.043). CONCLUSION: Dynamics of ventricular repolarization in HCM are affected by hypertrophy and fibrosis. LGE may confer an independent effect on QT dynamics which may increase the arrhythmogenic potential in HCM.

Cardiac CT Differentiates Left Atrial Appendage Thrombi from Circulatory Stasis in Acute Stroke Patients.

BACKGROUND/AIM: The left atrial appendage (LAA) is the most typical origin for a cardioembolic thrombusins' stroke etiology. Although transesophageal echocardiography (TEE) is widely used, this technique encounters difficulties in differentiating solid thrombus from circulatory stasis/spontaneous echo contrast (SEC). We assessed whether cardiac computed tomography (cCT) could more accurately detect LAA thrombi. MATERIALS AND METHODS: A total of 102 patients with suspected acute cardioembolic stroke/ transient ischemic attack (TIA) without chronic atrial fibrillation underwent arterial and venous phase cCT and TEE. TEE and cCT were consensus read to define LAA thrombus, while TEE alone was used to determine SEC. The LAA/aorta Houndsfield unit (HU) ratio was measured in both phases independently and blinded to prior visual readings. The optimal LAA/aorta HU ratio cut-off value for differentiating thrombi and SEC was estimated. RESULTS: TEE indicated 10 SECs and three thrombi. Consensus reading of cCT and TEE indicated that all thrombi detected in TEE were false-positive but revealed three actual thrombi missed in TEE. The LAA/aorta HU ratio correlated significantly with the presence of SEC both in arterial (p=0.019) and venous phases (p=0.024) and with the presence of thrombi in both phases (p<0.001). The best trade-off values for LAA/aorta HU ratio for the detection of thrombi was <0.245 in both phases. SEC was characterized with HU ratios of >0.245 and <0.577 in the arterial phase and>0.245 and <0.824 in the venous phase. Values of sensitivity, specificity, positive and negative predictive value and accuracy for detection of thrombi were 100% for cCT in both phases. CONCLUSION: cCT is more accurate than TEE in the detection of LAA thrombi, especially when combined with the measurement of LAA/aorta HU ratio.

Current perspectives in hypertrophic cardiomyopathy with the focus on patients in the Finnish population: a review.

Hypertrophic cardiomyopathy (HCM) is the most common inherited heart disease, with the prevalence of about 1/500. During the last two decades, the knowledge of the etiology, pathogenesis, risk stratification and prevention of sudden death in HCM has substantially advanced. Most often, HCM is familial and caused by mutations in sarcomere genes, inherited in an autosomal dominant manner. In Finland, genetic background of HCM is unique, with a few founder mutations in cardiac sarcomere genes accounting for a considerable proportion of the disease. Pathogenic mechanisms induced by disease-causing mutations are still poorly understood, although alterations in intracellular calcium handling and inefficient generation of contractile force in myocytes are considered key features in triggering the hypertrophic response. Clinical features of the disease are highly variable from no symptoms to the spectrum of exertional dyspnea, angina, palpitations, syncope and sudden death. In the current patient care, implantable cardioverter defibrillators (ICDs) are successfully used to prevent sudden cardiac death in high risk subjects. Targeted genetic testing is recommended to confirm the diagnosis in patients with HCM and to identify family members with the disease. Future research is needed to elucidate key cellular mechanisms leading to HCM, which may allow specific prevention and treatment of the disease. Key messages Hypertrophic cardiomyopathy, most often caused by defects in sarcomere genes, is the most common inherited heart disease, and a common cause of sudden cardiac death (SCD) in athletes and young subjects. Cardiac imaging, ECG and genetic testing are pivotal in the diagnosis of the disease in patients and first-degree relatives. Implantable cardioverter defibrillators in patients with high risk for SCD and tailored pharmacotherapy are efficient tools in patient care, but so far, exact mechanisms leading to cardiac hypertrophy in HCM are only partially understood, and there is no curative treatment for the disease.

Left ventricular mechanical dispersion is associated with nonsustained ventricular tachycardia in hypertrophic cardiomyopathy.

OBJECTIVE: We assessed the value of speckle tracking two-dimensional (2D) strain echocardiography (2DSE) measured mechanical dispersion (MD) with other imaging and electrocardiographic parameters in differentiating hypertrophic cardiomyopathy (HCM) patients with and without nonsustained ventricular tachycardia (NSVT) on 24-h ambulatory ECG monitoring. METHODS AND RESULTS: We studied 31 patients with HCM caused by the Finnish founder mutation MYBPC3-Q1061X and 20 control subjects with comprehensive 2DSE echocardiography and cardiac magnetic resonance imaging (CMRI). The presence of NSVT was assessed from ambulatory 24-h ECG monitoring. NSVT episodes were recorded in 11 (35%) patients with HCM. MD was significantly higher in HCM patients with NSVT (93 ± 41 ms) compared to HCM patients without NSVT (50 ± 18 ms, p = 0.012) and control subjects (41 ± 16 ms, p < 0.001). MD was the only variable independently associated with the presence of NSVT (OR: 1.60, 95% CI: 1.05-2.45, p = 0.030). Assessed by ROC curves, MD performed best in differentiating between HCM patients with and without NSVT (AUC = 0.81). CONCLUSIONS: Increased mechanical dispersion was associated with NSVT in HCM patients on 24-h ambulatory ECG monitoring. Key messages The prediction of sudden cardiac death in hypertrophic cardiomyopathy remains a challenge and novel imaging methods are required to identify individuals at risk of malignant ventricular arrhythmias. Mechanical dispersion by speckle tracking echocardiography is associated with NSVT on 24-h ambulatory ECG monitoring in patients with hypertrophic cardiomyopathy.

Cardiovascular magnetic resonance of mitral valve length in hypertrophic cardiomyopathy.

BACKGROUND: Previous data suggest that mitral valve leaflets are elongated in hypertrophic cardiomyopathy (HCM), and mitral valve leaflet elongation may constitute a primary phenotypic expression of HCM. Our objective was to measure the length of mitral valve leaflets by cardiovascular magnetic resonance (CMR) in subjects with HCM caused by a Finnish founder mutation in the myosin-binding protein C gene (MYBPC3-Q1061X), carriers of the same mutation without left ventricular hypertrophy, as well as in unselected consecutive patients with HCM, and respective controls. METHODS: Anterior mitral valve leaflet (AML) and posterior mitral valve leaflet (PML) lengths were measured by CMR in 47 subjects with the Q1061X mutation in the gene encoding MYBPC3 and in 20 healthy relatives without the mutation. In addition, mitral valve leaflet lengths were measured by CMR in 80 consecutive non-genotyped patients with HCM in CMR and 71 age- and gender-matched healthy subjects. RESULTS: Of the subjects with the MYBPC-Q1016X mutation, 32 had left ventricular hypertrophy (LVH, LV maximal wall thickness ≥ 13 mm in CMR) and 15 had no hypertrophy. PML was longer in patients with the MYBPC3-Q1061X mutation and LVH than in controls of the MYBPC group (12.8 ± 2.8 vs 10.6 ± 1.9 mm, P = 0.013), but the difference between the groups was not statistically significant when PML was indexed for BSA (P = 0.066), or when PML length was adjusted for BSA, age, gender, LV mass and ejection fraction (P = 0.195). There was no significant difference in the PML length in mutation carriers without LVH and controls (11.1 ± 3.4 vs 10.6 ± 1.9, P = 0.52). We found no difference in AML lengths between the MYBPC mutation carriers with or without hypertrophy and controls. In 80 consecutive non-genotyped patients with HCM, there was no difference either in AML or PML lengths in subjects with HCM compared to respective control subjects. CONCLUSIONS: In subjects with HCM caused by the Q1061X mutation in the MYBPC3 gene, the posterior mitral valve leaflets may be elongated, but mitral valve elongation does not constitute primary phenotypic expression of the disease. Instead, elongated mitral valve leaflets seem to be associated with body size and left ventricular remodeling.

Diagnostic Performance of Left Atrial Diameter Measurement in Computed Tomography to Detect Increased Left Atrial Volume.

BACKGROUND/AIM: The left atrium (LA) is frequently imaged in cardiac computed tomographic (cCT) examinations. The LA volume can be accurately measured with three-dimensional (3D) volumetry but this method is time consuming and thus not routinely used in clinical practice. Accordingly, increased LA size may be overlooked although volume enlargement is associated with adverse cardiovascular events. We evaluated the accuracy of LA diameter measurement in cCT and in transthoracic echocardiography (TTE) in the diagnosis of LA enlargement using 3D cCT as the reference standard. PATIENTS AND METHODS: Altogether, 146 patients with suspected cardiogenic stroke underwent cCT and TTE. LA volume by cCT was determined for all patients. LA diameter was measured in both modalities. Furthermore, 40 healthy controls were analyzed in order to assess the cut-off values for normal LA volume. Diagnostic performance of cCT and conventional TTE diametrical measurements for detecting enlarged LA volume were analyzed and compared using Cohen's kappa (κ). RESULTS: In controls, the mean LA volume was 59.8±15.3 ml and the mean LA diameter was 30.4±5.0 mm by cCT. The mean value plus twice the standard deviation, which was considered the upper limit, for normal LA volume and diameter were 90.4 ml and 40.4 mm, respectively. Age- and gender-matched patients with stroke had statistically significantly (p<0.001) larger LA volumes (85.5±21.1 vs. 59.8±15.3 ml) and diameters (37.6±5.7 vs. 30.4±5.0 mm) than controls. LA diameter measurement by cCT was more reliable in detecting an LA volume enlargement than the corresponding measurement with TTE (κ=0.489 vs. 0.234; p=0.002). CONCLUSION: An enlarged LA diameter measured by cCT was more reliable than TTE at detecting enlarged LA volume.

Acute phase IL-10 plasma concentration associates with the high risk sources of cardiogenic stroke.

BACKGROUND: Etiological assessment of stroke is essential for accurate treatment decisions and for secondary prevention of recurrence. There is evidence that interleukin-10 (IL-10) associates with ischemic stroke. The aim of this prospective study was to assess the levels of IL-10 in ischemic stroke with unknown or suspected cardiogenic etiology, and evaluate the correlation between IL-10 plasma concentration and the number of diagnosed high risk sources for cardioembolism. METHODS: A total of 141 patients (97 males; mean age 61±11 years) with acute ischemic stroke with unknown etiology or suspected cardiogenic etiology other than known atrial fibrillation (AF) underwent imaging investigations to assess high risk sources for cardioembolic stroke established by the European Association of Echocardiography (EAE). IL-10 was measured on admission to the hospital and on a three month follow-up visit. RESULTS: Acute phase IL-10 concentration was higher in patients with EAE high risk sources, and correlated with their number (p<0.01). In patients with no risk sources (n = 104), the mean IL-10 concentration was 2.7±3.1 ng/L (range 0.3-16.3 ng/L), with one risk source (n = 26) 3.7±5.5 ng/L (0.3-23.6 ng/L), with two risk sources (n = 10) 7.0±10.0 ng/L (1.29-34.8 ng/L) and with three risk sources (n = 1) 37.2 ng/L. IL-10 level was not significantly associated with cerebral infarct volume, presence of previous or recent myocardial infarction, carotid/vertebral artery atherosclerosis, paroxysmal AF registered on 24-hour ECG Holter monitoring or given intravenous thrombolytic treatment. CONCLUSION: IL-10 plasma concentration correlates independently with the number of EAE cardioembolic risk sources in patients with acute stroke. IL-10 may have potential to improve differential diagnostics of stroke with unknown etiology.

Increased visceral adipose tissue as a potential risk factor in patients with embolic stroke of undetermined source (ESUS).

PURPOSE: The etiology of an ischemic stroke remains undetermined in 20-35% of cases and many patients do not have any of the conventional risk factors. Increased visceral adipose tissue (VAT) is a suggested new risk factor for both carotid artery atherosclerosis (CAA) and atrial fibrillation (AF), but its role in the remaining stroke population is unknown. We assessed the amount of VAT in patients with embolic stroke of undetermined source (ESUS) after excluding major-risk cardioembolic sources, occlusive atherosclerosis, and lacunar stroke. METHODS: Altogether 58 patients (mean age 57.7 ± 10.2 years, 44 men) with ischemic stroke of unknown etiology but without CAA, known AF or small vessel disease underwent computed tomography angiography and assessment of VAT. For comparison VAT values from three different reference populations were used. Conventional risk factors (smoking, hypertension, diabetes, increased total and LDL-cholesterol, decreased HDL-cholesterol) were also registered. RESULTS: Mean VAT area was significantly higher in stroke patients (205 ± 103 cm2 for men and 168 ± 99 cm2 for women) compared to all reference populations (P < 0.01). 50% of male and 57% of female patients had an increased VAT area. In male patients, VAT was significantly higher despite similar body mass index (BMI). Increased VAT was more common than any of the conventional risk factors. CONCLUSION: Increased VAT was found in over half of our patients with ESUS suggesting it may have a role in the pathogenesis of thromboembolism in this selected group of patients.

Visually assessed severity of lumbar spinal canal stenosis is paradoxically associated with leg pain and objective walking ability.

BACKGROUND: Lumbar spinal stenosis (LSS) is the common term used to describe patients with symptoms related to the anatomical reduction of the lumbar spinal canal size. However, some subjects may have a markedly narrowed canal without any symptoms. This raises the question of what is the actual role of central canal stenosis in symptomatic patients. The purpose of this study was to compare radiological evaluations of LSS, both visually and quantitatively, with the clinical findings of patients with LSS. METHODS: Eighty patients [mean age 63 (11) years, 44% male], with symptoms severe enough to indicate LSS surgery, were included in this prospective single-center study. Lumbar magnetic resonance imaging was performed and one experienced neuroradiologist classified patients into three groups: 0 = normal or mild stenosis, 1 = moderate stenosis, and 2 = severe stenosis. In addition, the same observer measured the minimal dural sac area level by level from the inferior aspect of L1 to the inferior aspect of S1. The association between radiological and clinical findings were tested with Oswestry Disability Index, overall visual analog pain scale, specific low back pain, specific leg pain, Beck Depression Inventory, and walking distance on treadmill exercise test. RESULTS: In the visual classification of the central spinal canal, leg pain was significantly higher and walking distance achieved was shorter among patients with moderate central stenosis than in patients with severe central stenosis (7.33 (2.29) vs 5.80 (2.72); P = 0.008 and 421 (431) m vs 646 (436) m; P = 0.021, respectively). Patients with severe stenosis at only one level also achieved shorter walking distance than patients with severe stenosis of at least two levels. No correlation between visually or quantitatively assessed stenosis and other clinical findings was found. CONCLUSIONS: There is no straightforward association between the stenosis of dural sac and patient symptoms or functional capacity. These findings indicated that dural sac stenosis is not the single key element in the pathophysiology of LSS.

Preoperative MRI findings predict two-year postoperative clinical outcome in lumbar spinal stenosis.

PURPOSE: To study the predictive value of preoperative magnetic resonance imaging (MRI) findings for the two-year postoperative clinical outcome in lumbar spinal stenosis (LSS). METHODS: 84 patients (mean age 63±11 years, male 43%) with symptoms severe enough to indicate LSS surgery were included in this prospective observational single-center study. Preoperative MRI of the lumbar spine was performed with a 1.5-T unit. The imaging protocol conformed to the requirements of the American College of Radiology for the performance of MRI of the adult spine. Visual and quantitative assessment of MRI was performed by one experienced neuroradiologist. At the two-year postoperative follow-up, functional ability was assessed with the Oswestry Disability Index (ODI 0-100%) and treadmill test (0-1000 m), pain symptoms with the overall Visual Analogue Scale (VAS 0-100 mm), and specific low back pain (LBP) and specific leg pain (LP) separately with a numeric rating scale from 0-10 (NRS-11). Satisfaction with the surgical outcome was also assessed. RESULTS: Preoperative severe central stenosis predicted postoperatively lower LP, LBP, and VAS when compared in patients with moderate central stenosis (p<0.05). Moreover, severe stenosis predicted higher postoperative satisfaction (p = 0.029). Preoperative scoliosis predicted an impaired outcome in the ODI (p = 0.031) and lowered the walking distance in the treadmill test (p = 0.001). The preoperative finding of only one stenotic level in visual assessment predicted less postoperative LBP when compared with patients having 2 or more stenotic levels (p = 0.026). No significant differences were detected between quantitative measurements and the patient outcome. CONCLUSIONS: Routine preoperative lumbar spine MRI can predict the patient outcome in a two-year follow up in patients with LSS surgery. Severe central stenosis and one-level central stenosis are predictors of good outcome. Preoperative finding of scoliosis may indicate worse functional ability.

Morphological and volumetric analysis of left atrial appendage and left atrium: cardiac computed tomography-based reproducibility assessment.

OBJECTIVES: Left atrial appendage (LAA) dilatation and morphology may influence an individual's risk for intracardiac thrombi and ischemic stroke. LAA size and morphology can be evaluated using cardiac computed tomography (cCT). The present study evaluated the reproducibility of LAA volume and morphology assessments. METHODS: A total of 149 patients (47 females; mean age 60.9±10.6 years) with suspected cardioembolic stroke/transient ischemic attack underwent cCT. Image quality was rated based on four categories. Ten patients were selected from each image quality category (N = 40) for volumetric reproducibility analysis by two individual readers. LAA and left atrium (LA) volume were measured in both two-chamber (2CV) and transversal view (TV) orientation. Intertechnique reproducibility was assessed between 2CV and TV (200 measurement pairs). LAA morphology (A = Cactus, B = ChickenWing, C = WindSock, D = CauliFlower), LAA opening height, number of LAA lobes, trabeculation, and orientation of the LAA tip was analysed in all study subjects by three individual readers (447 interobserver measurement pairs). The reproducibility of volume measurements was assessed by intra-class correlation (ICC) and the reproducibility of LAA morphology assessments by Cohen's kappa. RESULTS: The intra-observer and interobserver reproducibility of LAA and LA volume measurements was excellent (ICCs>0.9). The LAA (ICC = 0.954) and LA (ICC = 0.945) volume measurements were comparable between 2CV and TV. Morphological classification (ĸ = 0.24) and assessments of LAA opening height (ĸ = 0.1), number of LAA lobes (ĸ = 0.16), trabeculation (ĸ = 0.15), and orientation of the LAA tip (ĸ = 0.37) was only slightly to fairly reproducible. CONCLUSIONS: LA and LAA volume measurements on cCT provide excellent reproducibility, whereas visual assessment of LAA morphological features is challenging and results in unsatisfactory agreement between readers.

Correlation of lateral stenosis in MRI with symptoms, walking capacity and EMG findings in patients with surgically confirmed lateral lumbar spinal canal stenosis.

BACKGROUND: To evaluate the clinical significance of lateral lumbar spinal canal stenosis (LLSCS), found by magnetic resonance imaging (MRI), through correlating the imaging findings with patient symptoms, walking capacity and electromyography (EMG) measurements. METHOD: 102 patients with symptoms of LSS referred for operative treatment were studied in this uncontrolled study. Of these patients, subjects with distinct only lateral LSS were included. Accordingly, 140 roots in 14 patients (mean age 58, range 48-76 years, male 43%) were evaluated. In MR images the entrance and mid zones of the lateral lumbar nerve root canal were graded as normal, narrowed but not compressed, or compressed. In quantitative analysis, the minimal widths of the lateral recess and mid zone area were measured. Clinical symptoms were recorded with the Oswestry Disability Index (ODI), overall Visual Analogue Scale (VAS), specific low back pain (LBP; NRS-11), specific leg pain (LP NRS-11), Beck Depression Inventory (BDI) and walking distance in the treadmill test. Lumbar paraspinal (L2- L5) and lower limb (L3 - S1) needle EMG studies were performed. The findings were classified root by root as 1 = normal, 2 = abnormal. The associations between radiological, EMG and clinical findings were tested with each other. RESULTS: EMG findings were normal in 92 roots and abnormal in 48 roots. All of the patients had at least one abnormal nerve root finding. Severity of the mid zone stenosis in MRI correlated with abnormal EMG findings (p = 0.015). Patients with abnormal EMG had also higher scores in the VAS (41.9 ± 25.7 vs 31.5 ± 18.1; p = 0.018), NRS leg pain (7.5 ± 1.5 vs 6.3 ± 2.1; p = 0.000) and BDI (9.8 ± 3.8 vs 8.0 ± 3.9; p = 0.014). However, no statistically significant correlations between MRI findings and clinical symptoms or walking capacity were found. CONCLUSIONS: Among persons previously selected for surgery, lateral stenosis seen on MRI correlates with EMG, and thus may be a clinically significant finding. Our EMG findings were also associated with patient symptoms. However, no relationships between the MRI findings and symptoms or walking capacity were found, suggesting their multifactorial etiology.

Determinants of left atrial appendage volume in stroke patients without chronic atrial fibrillation.

BACKGROUND: Left atrial appendage (LAA) volume has been shown to be increased in patients with acute cryptogenic stroke. Atrial fibrillation (AF) is a well-recognized risk factor but it is not the only one associated with LAA enlargement. The aim of the study was to clarify the multifactorial etiology of LAA enlargement in cardiogenic stroke/TIA patients without AF. METHODS: Altogether 149 patients with suspected cardioembolic stroke/TIA (47 females; mean age 61 years) underwent cardiac CT. Diagnosed AF on admittance was an exclusion criteria but 24-hour Holter ambulatory ECG revealed paroxysmal AF (PAF) in 20 patients. Body surface area adjusted LAA volume was evaluated. Eighteen different variables were registered including general characteristics, definite and potential causal risk factors for ischemic stroke/TIA, clinical echoparameters and CT based cardiac volumetric and adipose tissue measurements. A stepwise linear regression analysis was performed to achieve a model adjusted for the number of predictors of LAA volume increase. RESULTS: In linear regression analysis, the best model accounted for 30% of the variability in LAA volume, including PAF (19%) and enlarged left atrial volume (6%), enlarged left ventricle end-systolic diameter (3%) and decreased pericardial adipose tissue (2%). No multi-colinearity between variables was observed. In addition to PAF, no other definitive or potential causal risk factors could account for the LAA volume in these patients. CONCLUSIONS: LAA volume increase seems to be poorly associated with currently known stroke/TIA risk factors, except for AF. Targeting more comprehensive ECG monitoring for stroke patients with increased LAA volume should be considered.

Effect of middle cerebral artery territory ischemic stroke on QT interval.

BACKGROUND: Prolonged QT interval associates with increased risk for sudden cardiac death after acute ischemic stroke. However, pathophysiology of prolonged QT interval after stroke is poorly elucidated. In this study, we investigated whether QT interval dynamics is different in patients with right and left middle cerebral artery (MCA) territory stroke. METHOD: Electrocardiogram (ECG) intervals were compared between baseline (retrieved retrospectively from medical records) and admission (acquired at the acute hospital admission) in 33 patients (65 ± 9.5 years) with right or left MCA territory ischemic stroke. Head computed tomography (CT), cardiac ultrasound, and cardiac CT scans were undertaken. RESULTS: Stroke was located in the right MCA territory in 21 (64%) and in the left MCA territory in 12 (36%) patients. Patients with right and left MCA stroke were similar with respect to time interval between baseline and admission ECG recordings, positive history of heart disease, and left ventricular dimensions. Increase in heart rate-corrected QT interval (QTc) from baseline to admission was demonstrated to occur more often in patients with right (16 of 21; 76%) than in patients with left (3 of 12; 25%; P < .01) MCA stroke. ΔQTc between baseline and admission was significantly longer in patients with right (23 ± 23 milliseconds) than in patients with left (-11 ± 19 milliseconds; P < .0001) MCA stroke. Percent ΔQTc between baseline and admission was longer in patients with right (5.5% ± 5.5%) than in patients with left (-2.6% ± 4.7%; P < .001) MCA stroke. CONCLUSIONS: Right MCA ischemic stroke results in prolongation of QT interval. Findings indicate cerebral asymmetry in brain-heart interaction during acute ischemic stroke.