Abstract TP230: Left Atrial Appendage Volume Is Increased In More Than Half Of Patients With Cryptogenic Stroke

Background: Ischemic stroke without a well-defined etiology is labelled as cryptogenic, and it accounts for 30 − 40 % of strokes in modern stroke registries. Enlarged left atrial appendage (LAA) is the most typical origin for intracardiac thrombus formation. We studied whether increased LAA volume detected with cardiac computed tomography (cCT) constitutes a risk factor in cryptogenic stroke patients.

Materials and methods: Consecutive stroke or TIA patients with cryptogenic etiology for stroke after profound clinical, radiological and cardiological investigations were selected for the study. The 1993 TOAST criteriae modified by 2010 EAE recommendations for defining cardiac sources of embolism were used for classification. Eighty-two patients (57 males; mean age 58 years) were identified. Forty control subjects without cardiovascular diseases, matched for age and gender, were selected for pair-wise comparisons (21 males; mean age 54 years). LAA volume adjusted for body surface area was measured three dimensionally by tracing the borders of LAA on CT slices. The upper limit for normal LAA volume was defined as mean + 2 SD in control subjects.

Results: In control subjects LAA volume was 3.4 ± 1.1 mL/m 2 (range 1.3 − 6.0 mL/m 2 ). The upper limit for normal LAA was 5.6 mL/m 2 . Of the patients with cryptogenic stroke/TIA 45 (55 %) had enlarged LAA. In matched pair-wise comparisons LAA volume was 67 % larger in cryptogenic stroke/TIA patients than in control subjects (5.7 ± 2.0 mL/m 2 vs. 3.4 ± 1.1 mL/m 2 ; P < 0.001).

Conclusions: LAA is significantly enlarged in more than half of patients with cryptogenic stroke, and thus do not have atrial fibrillation as a preceding risk factor. LAA thrombosis may contribute in the pathogenesis of stroke in patients considered to have cryptogenic stroke after conventional evaluation.

Accuracy and reproducibility of a retrospective outcome assessment for lumbar spinal stenosis surgery

Background

Retrospective assessment of surgery outcome is considered problematic. The aims of this study were to evaluate the reproducibility and accuracy of a retrospective outcome assessment of lumbar spinal stenosis surgery with reference to prospective outcome scale measurements.

Method

Outcome of surgery from 100 lumbar spinal stenosis (LSS) patients was evaluated retrospectively from patient files of a 3-month outpatient visit performed according to a standard clinical protocol by two independent researchers. In the retrospective analysis, outcome was graded as 2 = good if the clinical condition had clearly improved, 1 = moderate if it had just slightly improved, 0 = poor if it had not improved or was even worse than before the surgical treatment (Retrospective 3- point scale). A prospectively assessed Oswestry Disability Index questionnaire (ODI), Visual analogue pain scale (VAS) and a patient satisfaction questionnaire were used as references of standards. Reproducibility of the measurements was evaluated.

Results

The retrospective 3-point scale correlated with ODI (r = 0.528; P < 0.001) and VAS (r = 0.368; P < 0.001). The agreement was better in the good and poor outcome than in the moderate outcome. Retrospective 3-point scale demonstrated substantial intra-rater and inter-rater repeatability (κ = 0.682, P < 0.001 and κ = 0.630, P < 0.001, respectively).

Conclusions

Retrospective assessment of spinal surgery outcome is highly reproducible. Accuracy is highest in the patients with poor and good surgical result.

Low-grade inflammation and the phenotypic expression of myocardial fibrosis in hypertrophic cardiomyopathy

Objective

To investigate the role of inflammation in the phenotypic expression of myocardial fibrosis in hypertrophic cardiomyopathy (HCM).

Design

Clinical study.

Setting

Kuopio University Hospital and University of Eastern Finland, Kuopio, Finland.

Subjects

Twenty-four patients with a single HCM-causing mutation D175N in the α-tropomyosin gene and 17 control subjects.

Main outcome measures

Endomyocardial biopsy samples taken from the patients with HCM were compared with matched myocardial autopsy specimens. Levels of high-sensitivity C-reactive protein (hsCRP) and proinflammatory cytokines were measured in patients and controls. Myocardial late gadolinium enhancement (LGE) in cardiac MRI (CMRI) was detected.

Results

Endomyocardial samples in patients with HCM showed variable myocyte hypertrophy and size heterogeneity, myofibre disarray, fibrosis, inflammatory cell infiltration and nuclear factor kappa B (NF-κB) activation. Levels of hsCRP and interleukins (IL-1β, IL-1RA, IL-6, IL-10) were significantly higher in patients with HCM than in control subjects. In patients with HCM, there was a significant association between the degree of myocardial inflammatory cell infiltration, fibrosis in histopathological samples and myocardial LGE in CMRI. Levels of hsCRP were significantly associated with histopathological myocardial fibrosis. hsCRP, tumour necrosis factor α and IL-1RA levels had significant correlations with LGE in CMRI.

Conclusions

A variable myocardial and systemic inflammatory response was demonstrated in patients with HCM attributable to an identified sarcometric mutation. Inflammatory response was associated with myocardial fibrosis, suggesting that myocardial fibrosis in HCM is an active process modified by an inflammatory response.

Visual and quantitative assessment of lateral lumbar spinal canal stenosis with magnetic resonance imaging

BACKGROUND

Lateral lumbar spinal canal stenosis is a common etiology of lumbar radicular symptoms. Quantitative measurements have commonly demonstrated better repeatability than visual assessments. We are not aware of any studies examining the repeatability of quantitative assessment of the lateral canal.

PURPOSE

To evaluate the repeatability of visual assessments and newly developed quantitative measurements of lateral lumbar spinal canal stenosis using magnetic resonance imaging (MRI).

MATERIAL AND METHODS

Twenty-eight patients with lateral lumbar spinal canal stenosis or prior spinal surgery with recurrent symptoms were imaged with MRI. A radiologist, a neurosurgeon and a spine research trainee graded visually and quantitatively subarticular (n = 188) and foraminal zones (n = 260) of the lateral spinal canal. Quantitative measurements included the minimal subarticular width and the cross-sectional area of the foramen.

RESULTS

The repeatability of visual assessment at the subarticular zone and foraminal zones between raters varied from 0.45-0.59 and 0.42-0.53, respectively. Similarly, the intraclass correlation coefficients for the quantitative measurements varied from 0.67-0.71 and 0.66-0.76, respectively. The intra-rater repeatability for the visual assessments of the subarticular and foraminal zones was 0.70 and 0.62, respectively, while the corresponding intraclass correlation coefficients for quantitative measurements were 0.83 and 0.81, respectively.

CONCLUSION

Inter-rater repeatability of visual assessments of lateral stenosis is moderate, whereas quantitative measurements of both subarticular width and the cross-sectional area of the foramen have substantial reproducibility and may be particularly useful for longitudinal studies and research purposes. The clinical value of these parameters requires further study.

N-terminal pro-atrial natriuretic peptide reflects cardiac remodelling in stage 1 hypertension

Early detection of left ventricular hypertrophy (LVH) is beneficial, since treatment-induced regression of LVH has been unequivocally associated with a better prognosis. Our aim was to study the relation of cardiac remodelling and natriuretic peptides (NPs) in stage 1 hypertension. We studied 175 (46±7 years, 87 women and 88 men) apparently healthy middle-aged that had never been treated for hypertension. Left ventricular and atrial parameters were determined by magnetic resonance imaging. Systolic blood pressure (BP) correlated with left ventricular mass index (LVMI) (r=0.23, P<0.01) and ventricular septum thickness index (IVSI) (r=0.29, P<0.001). N-terminal pro-B-type NP (NT-proBNP) or N-terminal pro-atrial NP (NT-proANP) did not correlate with BP, LVMI or IVSI. NT-proANP correlated with left atrial area index (LAAI) (r=0.38, P<0.001), and subjects with LVH had higher LAAI than subjects with normal left ventricular geometry and no LVH (11.2±0.3 vs 10.0±0.2 cm(2) m(-2), P<0.001). In conclusion, measurement of NT-proBNP or NT-proANP does not appear to discriminate LVH in middle-aged, never treated and apparently healthy hypertensives. NT-proANP, but not NT-proBNP, reflects early cardiac remodelling in hypertensive heart disease.

Detection and quantification of rotator cuff tears with ultrasonography and magnetic resonance imaging - a prospective study in 77 consecutive patients with a surgical reference

The aim of this study was to compare the accuracy of ultrasonography (US) and magnetic resonance artrography (MRA) for the detection and measurement of rotator cuff tears, using surgical findings as a standard. A total of 77 consecutive patients with suspected rotator cuff tears were prospectively studied with US and MRA. Rotator cuff tears were identified by US with sensitivity, specificity, positive predictive and negative predictive values of 92%, 45%, 91% and 50%, respectively, and by MRA with values of 97%, 82%, 97% and 82%, respectively. US was not reliable for differentiating between partial and full thickness tears. US and MRA underestimated the tear sizes by an average of 15 mm and 4 mm, respectively. Our results suggest that US could be used as a screening test to confirm a suspected rotator cuff tear. In patients with negative findings, an MRA should be considered for substantiation.

Cardiac sympathetic activity is associated with inflammation and neurohumoral activation in patients with idiopathic dilated cardiomyopathy

BACKGROUND

Idiopathic dilated cardiomyopathy (IDC) is characterized by sympathetic nervous overactivity, inflammation and neurohumoral activation; however, their interrelationships are poorly understood.

METHODS AND RESULTS

We studied 99 patients with IDC (age 54 +/- 1 years, left ventricular ejection fraction (EF) 40 +/- 1%, maximum oxygen uptake (VO(2)max) 20 +/- 1 ml kg(-1) min(-2), mean +/- SEM) by using (123)I-metaiodobenzylguanidine (MIBG) imaging. MIBG washout and MIBG heart/mediastinum (H/M)-ratio at 4 h postinjection were calculated. In addition, the plasma levels of interleukin (IL)-6 and N-terminal B-type natriuretic peptide (NT-proBNP) were measured. MIBG washout and MIBG H/M ratio had a significant correlation with IL-6 (r = 0.42, P<0.001 and r = -0.31, P<0.01) and NT-proBNP (r = 0.48, P<0.001 and r = -0.40, P<0.001). During a median follow-up of 4.1 years, 20 patients (20%) had an adverse cardiac event (death, heart transplantation or application of biventricular pacemaker or implantable cardioverter-defibrillator). In these patients, MIBG washout was higher (53 +/- 4 versus 40 +/- 2%, P = 0.01) and H/M ratio lower (1.38 +/- 0.04 versus 1.51 +/- 0.02, P = 0.01) than in patients without an event.

CONCLUSIONS

In dilated cardiomyopathy, myocardial sympathetic innervation and activity are related to inflammation and neurohumoral activation. These relationships are at least partly independent of left ventricular function and exercise capacity.

Influence of 12 weeks of jogging on magnetic resonance-determined left ventricular characteristics in previously sedentary subjects free of cardiovascular disease

Hypertrophy of the left ventricle is a diagnostic dilemma in subjects who engage in regular endurance exercise. We studied prospectively whether endurance training in previously sedentary young and middle-aged men and women can alter left ventricular (LV) characteristics. We recruited 33 healthy young and middle-aged subjects (18 women, 15 men, ages 21 to 59 years) to undergo 12 weeks of home-based brisk walking and jogging at a target heart rate > or =120 beats/min for > or =30 minutes 3 times a week. LV characteristics were measured by cine magnetic resonance imaging. Training intensity as estimated by heart rate correlated positively with the increase in LV myocardial area (r = 0.51, p = 0.005) in the 28 men and women completing the study. In the 13 men and women who trained with heart rate of > or =120 beats/min, LV myocardial area was larger after than before training (17.7 +/- 2.9 vs 16.8 +/- 2.8 cm(2), p <0.05). Moreover, in these subjects LV myocardial area increased more (5.5 +/- 9.0% vs -3.0 +/- 5.0%) than in the 15 men and women who trained at a lower intensity (p <0.05). LV end-systolic and end-diastolic area and ejection fraction did not change significantly. In conclusion, moderate-to-vigorous endurance training at moderate volumes does not influence LV end-diastolic volume or ejection fraction, but has a minor influence on LV hypertrophy in previously sedentary young and middle-aged men and women.

Significance of plasma levels of N-terminal Pro-B-type natriuretic peptide on left ventricular remodeling in non-obstructive hypertrophic cardiomyopathy attributable to the Asp175Asn mutation in the alpha-tropomyosin gene

Hypertrophic cardiomyopathy (HC) is an inherited heart disease characterized by left ventricular (LV) remodeling. The present study was conducted to investigate the association of N-terminal pro-B-type natriuretic peptide (NT-pro-BNP) levels with LV remodeling on magnetic resonance imaging and procollagen formation in 17 healthy controls and 24 patients with nonobstructive HC attributable to an identical Asp175Asn (aspartic acid to asparagine at codon 175) mutation in the alpha-tropomyosin gene. None of the patients had history of decompensated heart failure, and all patients had normal LV ejection fraction. Patients with HC had higher NT-pro-BNP levels compared with controls (median 60 pmol/L, range <40 to 359, vs <40 pmol/L; p <0.001), but 9 patients with HC had normal NT-pro-BNP levels (<40 pmol/L). In patients with HC, levels of NT-pro-BNP were correlated significantly with LV end-systolic volume index (r = 0.50, p <0.05), LV mass index (r = 0.47, p <0.05), proportion of hypokinetic segments (r = 0.50, p <0.05), and levels of serum aminoterminal propeptide of type III procollagen (r = 0.52, p <0.01). When patients with HC were divided into 3 groups on the basis of their NT-pro-BNP levels, there were statistically significant linear associations of LV end-systolic volume (test for linearity p = 0.034), LV mass index (p = 0.009), proportion of hypokinetic segments (p = 0.016), and levels of serum aminoterminal propeptide of type III procollagen (p = 0.020) with NT-pro-BNP levels over the 3 groups, suggesting a tight relation between LV remodeling and levels of NT-pro-BNP. In conclusion, in patients with nonobstructive HC attributable to an Asp175Asn mutation in the alpha-tropomyosin gene, elevated NT-pro-BNP levels are associated with incipient LV remodeling, suggesting that NT-pro-BNP could be used to diagnose insidious unfavorable LV remodeling in HC.

Electrocardiographic left ventricular hypertrophy has low diagnostic accuracy in middle-aged subjects

OBJECTIVE

To evaluate the usefulness of electrocardiographic left ventricular hypertrophy (ECG LVH) as a marker of LVH in middle-aged subjects.

METHODS

LVH was determined by cardiovascular magnetic resonance imaging (MRI) in 188 apparently healthy middle-aged [97 men (45+/-7 years) and 91 women (47+/-6 years)]. Receiver operating characteristic (ROC) curves, test sensitivity, specificity, positive and negative predictive values for identifying LVH at different ECG criteria were calculated.

RESULTS

Systolic and diastolic blood pressures were 142+/-13 mmHg and 90+/-8 mmHg in men and 139+/-10 mmHg and 90+/-8 mmHg in women, respectively. LVMI was 78+/-17 g/m2 in men and 67+/-12 g/m2 in women, and 14% of men and 22% of women had LVH in cardiac MRI. Only Sokolow-Lyon and Sokolow-Lyon product had the area under the ROC curve over 0.70. Sokolow-Lyon product had the highest sensitivity (47%). All ECG criteria had high negative predictive values, but the positive predictive values were below 46%.

CONCLUSIONS

Commonly used ECG criteria of LVH have low discrimination ability in middle-aged subjects. ECG LVH alone should not be used as a marker of target organ damage in middle-aged, never treated and apparently healthy hypertensives.

Myocardial perfusion, oxidative metabolism, and free fatty acid uptake in patients with hypertrophic cardiomyopathy attributable to the Asp175Asn mutation in the α-tropomyosin gene: A positron emission tomography study

BACKGROUND

The relationship between myocardial metabolic changes and the severity of left ventricular (LV) hypertrophy in patients with hypertrophic cardiomyopathy (HCM) is largely unknown. We characterized metabolic abnormalities in patients with a genetically identical cause for HCM but with variable LV hypertrophy.

METHODS AND RESULTS

Eight patients with HCM attributable to the Asp175Asn mutation in the alpha-tropomyosin gene underwent myocardial perfusion, oxidative, and free fatty acid (FFA) metabolism measurements via positron emission tomography and oxygen 15-labeled water, carbon 11 acetate, and fluorine 14(R,S)-[18F] Fluoro-6-thia-heptadecanoic acid (18 FTHA). LV mass, work, and efficiency were assessed by echocardiography. Thirty-six healthy volunteers served as control subjects. Compared with control subjects, HCM patients had increased myocardial oxidative metabolism and FFA uptake (P < .05). However, in patients, LV mass was inversely related to global myocardial perfusion, oxidative metabolism, and FFA uptake (all P < .03), and regional wall thickness was inversely related to regional perfusion (P < .01), oxidative metabolism (P < .001), and FFA uptake (P < .01). Therefore patients with mild (LV mass less than median of 177 g) but not advanced LV hypertrophy were characterized by increased perfusion, oxidative metabolism, and LV efficiency as compared with control subjects (P < .05).

CONCLUSIONS

In HCM attributable to the Asp175Asn mutation in the alpha-tropomyosin gene, myocardial oxidative metabolism and FFA metabolism are increased and inversely related to LV hypertrophy at both the whole heart and regional level. Increased metabolism and efficiency characterize patients with mild myocardial hypertrophy. These hypermetabolic alterations regress with advanced hypertrophy.

Characterization and molecular detection of atherothrombosis by magnetic resonance--potential tools for individual risk assessment and diagnostics

This review focuses on recent non-invasive or minimally invasive magnetic resonance (MR) approaches to study atherothrombosis. The potential benefits of combining diverse metabolic information obtained by the variety of MR techniques from tissues in vivo and ex vivo and from body fluids in vitro are also briefly discussed. A well established methodology is available for lipoprotein subclass quantification from plasma by 1H MR spectroscopy providing information for assessing the long-term risk of atherosclerosis. Multi-contrast MR imaging in vivo relying on endogenous contrast allows partial characterization of components in atherothrombotic plaques. The use of exogenous contrast agents in MR angiography enhances blood-tissue contrast and provides functional information on plaque metabolism, improving plaque characterization and assessment of plaque vulnerability by MR imaging. Recent applications of molecular targeted MR imaging have revealed novel opportunities for specific early detection of atherothrombotic processes, such as angiogenesis and accumulation of macrophages. Currently, MR imaging and spectroscopy can produce such metabolic in vivo and in vitro information that in combination could facilitate the screening, identification and follow-up of cardiovascularly vulnerable patients in research settings. The recent developments imply that in the near future MR techniques will be part of clinical protocols for individual diagnostics in atherothrombosis.

Repair of right ventricular free wall defect with a de-epithelized pedicled myocutaneous latissimus dorsi muscle flap

Rupture of the right ventricle may occur because of sternal dehiscence or mediastinitis after cardiac surgery. Direct suture, polytetrafluoroethylene patch, fasciae, and muscle flaps have been used to close a right ventricular rupture. A unique occurrence of repair of a full-thickness right ventricle defect with a de-epithelized myocutaneous flap is presented. Our patient experienced a rupture of the right ventricle complicating sternal wound infection. The rupture was reconstructed with a polytetrafluoroethylene patch, but the patch needed to be removed because of infection. The defect was reconstructed with a de-epithelized myocutaneous latissimus dorsi flap. The patient indicated no signs of complication during follow-up.

Very acute cardiac toxicity during BEAC chemotherapy in non-Hodgkin's lymphoma patients undergoing autologous stem cell transplantation

Cardiotoxicity is potentially the most threatening nonhaematological side effect of high-dose CY. We prospectively evaluated the very acute cardiac effects of high-dose CY in 17 adult non-Hodgkin's lymphoma (NHL) patients receiving CY 1500 mg/m2/day as a part of BEAC high-dose therapy (HDT). Magnetic resonance imaging (MRI) and plasma natriuretic peptide (NT-proBNP, NT-proANP) measurements were performed prior to HDT (d-7) and just after completing HDT (d-2). After the high-dose CY left atrial end-systolic area increased from 15.2+/-1.2 to 18.5+/-1.4 cm2 (P=0.001), left ventricular end-diastolic volume from 136.1+/-12.3 to 156.6+/-11.1 cm3 (P=0.04) and left ventricular end-systolic volume from 67.4+/-7.8 to 75.3+/-7.1 cm3 (P=0.018). However, no significant change in left ventricular ejection fraction (LVEF) was observed. At the same time, plasma levels of NT-proBNP increased from 134.9+/-53.3 to 547.1+/-168.4 pmol/l (P=0.003) and NT-proANP from 481.1+/-105.5 to 1056.6+/-193.1 pmol/l (P=0.001), respectively. To conclude, high-dose CY results in very acute cardiac toxicity characterised by enlargement of the heart chambers in NHL patients previously treated with anthracyclines. This toxicity can be detected with increased concentrations of circulating natriuretic peptides but not with LVEF measurement.

Cine MR Imaging of Myocardial Contractile Impairment in Patients with Hypertrophic Cardiomyopathy Attributable to Asp175Asn Mutation in the α-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.

Multi-detector row CT angiography in the assessment of carotid artery disease in symptomatic patients: comparison with rotational angiography and digital subtraction angiography

BACKGROUND AND PURPOSE

Compared with the single-detector technique, multi-detector row CT angiography permits larger anatomic coverage that includes both the epiaortic and entire carotid circulations. We evaluated the accuracy of multi-detector row CT angiography by using multiplanar reformation (MPR) for measuring carotid artery diameters compared with that of rotational angiography. We also evaluated the diagnostic performance of CT angiography compared with digital subtraction angiography (DSA).

METHODS

In 35 patients, CT angiograms of 70 carotid arteries were compared with DSA images, and CT angiograms of 33 carotid arteries were compared with rotational angiograms. CT angiographic interpretation was performed first interactively at a workstation. Diameter measurements of normal and stenosed carotid arteries were performed on cross-sectional and oblique sagittal MPRs. Degree of stenosis was calculated per North American Symptomatic Carotid Endarterectomy Trial criteria independently by two observers for each technique.

RESULTS

Degree of stenosis was slightly underestimated with CT angiography, with mean differences (+/- SD) per observer of 6.9 +/- 17.6% and 10.7 +/- 16.1% for cross-sectional and 2.8 +/- 19.2% and 9.1 +/- 16.8% for oblique sagittal MPRs compared with rotational angiography. CT angiography was somewhat inaccurate for measuring the absolute minimal diameter of high-grade stenoses. On symptomatic sides (n = 35), interactive CT angiographic interpretation combined with MPR measurements for lesions with a visual estimate of 50% or greater stenosis achieved a sensitivity of 95% (20/21) and specificity of 93% (13/14) in the detection of carotid stenosis (>/= 50%) verified with DSA.

CONCLUSION

Regardless of slight underestimation of carotid stenosis with CT angiography compared with rotational angiography, diagnostic performance of CT angiography with interactive interpretation proved to be good. Also, the method is highly sensitive for detection of carotid artery stenosis, indicating the suitability of CT angiography as a screening method for symptomatic patients. For hemodynamically significant stenoses revealed by CT angiographic screening, conventional angiography still seems to be necessary.

Is it time for cardiac innervation imaging?

The autonomic nervous system plays an important role in the regulation of cardiac function and the regional distribution of cardiac nerve terminals can be visualized using scintigraphic techniques. The most commonly used tracer is iodine-123-metaiodobenzylguanidine (MIBG) but C-11-hydroxyephedrine has also been used with PET. When imaging with MIBG, the ratio of heart-to-mediastinal counts is used as an index of tracer uptake, and regional distribution is also assessed from tomographic images. The rate of clearance of the tracer can also be measured and indicates the function of the adrenergic system. Innervation imaging has been applied in patients with susceptibility to arrhythmias, coronary artery disease, hypertrophic and dilated cardiomyopathy and anthracycline induced cardiotoxicity. Abnormal adrenergic innervation or function appear to exist in many pathophysiological conditions indicating that sympathetic neurons are very susceptible to damage. Abnormal findings in innervation imaging also appear to have significant prognostic value especially in patients with cardiomyopathy. Recently, it has also been shown that innervation imaging can monitor drug-induced changes in cardiac adrenergic activity. Although innervation imaging holds great promise for clinical use, the method has not received wider clinical acceptance. Larger randomized studies are required to confirm the value of innervation imaging in various specific indications.