Ulrik Sloth Kristoffersen

Detection of Pulmonary Embolism with Combined Ventilation–Perfusion SPECT and Low-Dose CT: Head-to-Head Comparison with Multidetector CT Angiography

The diagnosis of pulmonary embolism (PE) is usually established by a combination of clinical assessment, D-dimer testing, and imaging with either pulmonary ventilation–perfusion (V/Q) scintigraphy or pulmonary multidetector CT (MDCT) angiography. Both V/Q SPECT and MDCT angiography seem to have high diagnostic accuracy. However, only limited data directly comparing these 2 modalities are available. Hybrid γ-camera/MDCT systems have been introduced and allow simultaneous 3-dimensional lung V/Q SPECT and MDCT angiography, suitable for diagnosing PE. The aim of our study was to compare, in a prospective design, the diagnostic ability of V/Q SPECT, V/Q SPECT combined with low-dose CT, and pulmonary MDCT angiography obtained simultaneously using a combined SPECT/MDCT scanner in patients suspected of having PE. Methods: Consecutive patients from June 2006 to February 2008 suspected of having acute PE were referred to the Department of Nuclear Medicine at Rigshospitalet or Frederiksberg Hospital, Denmark, for V/Q SPECT as a first-line imaging procedure. The number of eligible patients was 196. Patients with positive D-dimer results (>0.5 mmol/mL) or a clinical assessment with a Wells score greater than 2 were included and underwent V/Q SPECT, low-dose CT, and pulmonary MDCT angiography in a single session. Patient follow-up was 6 mo. Results: A total of 81 simultaneous studies were available for analysis, of which 38% were from patients with PE. V/Q SPECT had a sensitivity of 97% and a specificity of 88%. When low-dose CT was added, the sensitivity was still 97% and the specificity increased to 100%. Perfusion SPECT with low-dose CT had a sensitivity of 93% and a specificity of 51%. MDCT angiography alone had a sensitivity of 68% and a specificity of 100%. Conclusion: We conclude that V/Q SPECT in combination with low-dose CT without contrast enhancement has an excellent diagnostic performance and should therefore probably be considered first-line imaging in the work-up of PE in most cases.

Comparison of V/Q SPECT and planar V/Q lung scintigraphy in diagnosing acute pulmonary embolism.

PurposePlanar ventilation/perfusion (V/Q) scintigraphy is currently the standard method for the diagnosis of pulmonary embolism (PE) in most nuclear medicine centers. However, recent studies have shown a superior sensitivity and specificity when applying V/Q single photon emission computed tomography (SPECT) in diagnosing PE. This study evaluated the diagnostic performance of three-dimensional V/Q SPECT in comparison with planar V/Q scintigraphy. Materials and methodsConsecutive patients suspected of acute PE from June 2006 to February 2008 were referred to the Department of Nuclear Medicine at Frederiksberg Hospital, Denmark to a V/Q SPECT, as the first-line imaging procedure. Patients with positive D-dimer (>0.5 mg/l) or after clinical assessment with a Wells score of more than 2 were included and had a V/Q SPECT, low-dose CT, planar V/Q scintigraphy, and pulmonary multidetector computer tomography angiography performed the same day. Ventilation studies were performed using 81mKr. Patient follow-up was at least 6 months. ResultsA total of 36 patient studies were available for analysis, of which 11 (31%) had PE. V/Q SPECT had a sensitivity of 100% and a specificity of 87%. Planar V/Q scintigraphy had a sensitivity of 64% and a specificity of 72%. ConclusionWe conclude that V/Q SPECT has a superior diagnostic performance compared with planar V/Q scintigraphy and should be preferred when diagnosing PE.

Mesenchymal stromal cell derived endothelial progenitor treatment in patients with refractory angina

Abstract Aims. We evaluated the feasibility, safety and efficacy of intra-myocardial injection of autologous mesenchymal stromal cells derived endothelial progenitor cell (MSC) in patients with stable coronary artery disease (CAD) and refractory angina in this first in man trial. Methods and results. A total of 31 patients with stable CAD, moderate to severe angina and no further revascularization options, were included. Bone marrow MSC were isolated and culture expanded for 6–8 weeks. It was feasible and safe to establish in-hospital culture expansion of autologous MSC and perform intra-myocardial injection of MSC. After six months follow-up myocardial perfusion was unaltered, but the patients increased exercise capacity (p < 0.001), reduction in CCS Class (p < 0.001), angina attacks (p < 0.001) and nitroglycerin consumption (p < 0.001), and improved Seattle Angina Questionnaire (SAQ) evaluations (p < 0.001). For all parameters there was a tendency towards improved outcome with increasing numbers of cells injected. In the MRI substudy: ejection fraction (p < 0.001), systolic wall thickness (p = 0.03) and wall thickening (p = 0.03) all improved. Conclusions. The study demonstrated that it was safe to treat patients with stable CAD with autologous culture expanded MSC. Moreover, MSC treated patients had significant improvement in left ventricular function and exercise capacity, in addition to an improvement in clinical symptoms and SAQ evaluations. Trial registration: ClinicalTrials.gov identifier: NCT00260338.

Reduction in circulating markers of endothelial dysfunction in HIV-infected patients during antiretroviral therapy.

Antiretroviral therapy (ART) in HIV‐infected patients is associated with increased cardiovascular risk. Circulating markers of endothelial dysfunction may be used to study early atherogenesis. The aim of our study was to investigate changes in such markers during initiation of ART.

Changes in lung function of HIV-infected patients: a 4·5-year follow-up study

To investigate the development of lung function in HIV‐infected patients.

Autonomic dysfunction in HIV patients on antiretroviral therapy: studies of heart rate variability

Background:  The presence of autonomic dysfunction in HIV patients is largely unknown. Early studies found autonomic dysfunction in patients with AIDS. Introduction of highly active antiretroviral combination therapy (ART) has dramatically changed the course of the disease and improved prognosis and decreased morbidity. At present it is not known whether introduction of ART also has decreased autonomic dysfunction.

Changes in biomarkers of cardiovascular risk after a switch to abacavir in HIV‐1‐infected individuals receiving combination antiretroviral therapy

To investigate, using a longitudinal design, whether biomarkers of cardiovascular risk change after a switch to an abacavir (ABC)‐containing regimen in HIV‐1‐infected individuals already receiving combination antiretroviral therapy (ART).

Carotid intima-media thickness in HIV patients treated with antiretroviral therapy.

Introduction:  Increased cardiovascular risk in HIV patients in antiretroviral therapy (ART) may be due to HIV infection, direct effect of ART or dyslipidaemia induced by ART. Our aim was to study the relative importance of HIV, ART and dyslipidaemia on atherosclerosis, assessed by the comparison of carotid artery intima–media thickness (IMT) in non‐smoking HIV patients with high or low serum cholesterol levels as well as in healthy volunteers.

Silent Ischemic Heart Disease and Pericardial Fat Volume in HIV-Infected Patients: A Case-Control Myocardial Perfusion Scintigraphy Study

Objectives to determine the prevalence of asymptomatic ischemic heart disease (IHD) in HIV patients by myocardial perfusion scintigraphy (MPS) and to determine the value of coronary artery calcium score (CACS), carotid intima-media thickness (cIMT) and pericardial fat volume as screening tools for detection of IHD in subjects with HIV. Background Patients with HIV seem prone to early development of IHD. Methods 105 consecutive HIV patients (mean age 47.4 years; mean duration of HIV 12.3 years; mean CD4+ cell count 636×106/L; all receiving antiretroviral therapy) and 105 controls matched for age, gender and smoking status, without history of IHD were recruited. MPS, CACS, cIMT, pericardial fat volume, and cardiovascular risk scores were measured. Results HIV patients demonstrated higher prevalence of perfusion defects than controls (18% vs. 0%; p<0.001) despite similar risk scores. Of HIV patients with perfusion defects, 42% had a CACS = 0. CACS and cIMT were similar in HIV patients and controls. HIV patients on average had 35% increased pericardial fat volume and increased concentration of biomarkers of atherosclerosis in the blood. HIV patients with myocardial perfusion defects had increased pericardial fat volume compared with HIV patients without perfusion defects (314±43 vs. 189±12 mL; p<0.001). Conclusions HIV patients had an increased prevalence of silent IHD compared to controls as demonstrated by MPS. The finding was strongly associated with pericardial fat volume, whereas cardiovascular risk scores, cIMT and CACS seem less useful as screening tools for detection of myocardial perfusion defects in HIV patients.

Effect of eight weeks of endurance exercise training on right and left ventricular volume and mass in untrained obese subjects: a longitudinal MRI study.

The aim of the present investigation was to examine how 8 weeks of intense endurance training influenced right and left ventricular volumes and mass in obese untrained subjects. Ten overweight subjects (19–47 years; body mass index of 34±5 kg/m2) underwent intensive endurance training (rowing) three times 30 min/week for 8 weeks at a relative intensity of 72±8% of their maximal heart rate response (mean±SD). Before and after 8 weeks of endurance training, the left and the right end‐diastolic volume (EDV), end‐systolic volume (ESV), ejection fraction (EF), stroke volume (SV) and ventricular mass (VM) were measured by Magnetic resonance imaging (MRI). Submaximal heart rate decreased from 126±5 to 113±3 b.p.m. (10%; P<0.01), and from 155±5 to 141±4 b.p.m. (9%; P<0.001) at submaximal workloads of 70 and 140 W (110 W for women), respectively (mean±SEM). Resting ventricular parameters increased significantly: left ventricular SV, EDV and VM increased by 6%, 7% and 13%, respectively (P<0.01). The right side of the heart showed significant changes in SV, EDV and VM with increase of 4%, 4% and 12%, respectively (P<0.05). Eight weeks of endurance training significantly increased left ventricular SV and right ventricular SV, due to an increase in left ventricular EDV and right ventricular EDV. Furthermore, left VM and right VM increased. We conclude that using MRI and a longitudinal design it was possible to demonstrate similar and balanced changes in the right and left ventricle in response to training.