Non-ECG-gated CT pulmonary angiography and the prediction of right ventricular dysfunction in patients suspected of pulmonary embolism.

PURPOSE: Right ventricular dysfunction (RVD) is an important prognostic factor of 30-day mortality in patients with acute pulmonary embolism (PE). The aim of our study was to evaluate whether non-electrocardiogram (ECG)-gated cardiovascular parameters attained during computed tomography pulmonary angiography (CTPA) could predict RVD in patients suspected of PE using ECG-gated cardiac CT angiography as reference. METHODS: Consecutive patients suspected of PE were referred to a ventilation/perfusion single-photon emission tomography (V/Q-SPECT) as first-line imaging procedure. Patients had a V/Q-SPECT/CT, a CTPA and an ECG-gated cardiac CT angiography performed the same day. RESULTS: A total of 71 patients were available for analysis. Seventeen patients (24%) had RVD. The non-ECG-gated dimensions of left and right ventricle and the major vessels were correlated with ECG-gated cardiac dimensions. The size of the pulmonary trunk could identify patients with RVD: AUC (0·67, 95% confidence intervals (CIs) 0·52-0·82) as seen in the ROC curve (P<0·05). With a cut-off value of the pulmonary trunk of 29 mm, the sensitivity and specificity were 70·6% and 55·5%, respectively. The positive predictive and negative predictive values for detection of RVD were 59·1% and 85·7%, respectively. CONCLUSION: In the present study, we demonstrated correlation between ECG-gated cardiac dimensions and non-ECG-gated cardiovascular parameters, however with only moderate diagnostic accuracies. We demonstrated that the dimension of the pulmonary trunk might be of value in detection of patients with RVD. We suggest further studies on the potential value of non-ECG-gated cardiac dimensions in patients suspected of PE.

Stability of percutaneously implanted markers for lung stereotactic radiotherapy.

The purpose of this study was to evaluate the stability of complex markers implanted into lung tumors throughout a course of stereotactic body radiotherapy (SBRT). Fifteen patients referred for lung SBRT were prospectively included. Radio-opaque markers were implanted percutaneously, guided by computed tomography (CT). Deep inspiration breath-hold CT scans (BHCT) were acquired at planning and on three treatment days. The treatment days' BHCTs were registered to the planning BHCT. Intraobserver uncertainty in both tumor and marker registration was determined. Deviations in the difference between tumor and marker-based image registrations of the BHCT scans during treatment quantified the marker stability. Marker position deviation relative to tumor position of less than 2 mm in all three dimensions was considered acceptable for treatment delivery precision. Intra observer uncertainties for image registration in the left-right (LR), anterior-posterior (AP), craniocaudal (CC) directions and three-dimensional vector (3D) were 0.9 mm, 0.9 mm, 1.0 mm, and 1.1 mm (SD) for tumor registration and 0.3 mm, 0.5 mm, 0.7 mm, and 0.7 mm (SD) for marker registration. Mean 3D differences for tumor registrations on all days were significantly larger than for 3D marker registrations (p = 0.007). Overall median differences between tumor and marker position were 0.0 mm (range -2.9 to 2.6 mm) in LR, 0.0 mm (-1.8 to 1.5 mm) in AP, and -0.2 mm (-2.6 to 2.8 mm) in CC directions. Four patients had deviations exceeding 2 mm in one or more registrations throughout the SBRT course. This is the first study to evaluate stability of complex markers implanted percutaneously into lung tumors for image guidance in SBRT. We conclude that the observed stability of marker position within the tumor indicates that complex markers can be used as surrogates for tumor position during a short course of SBRT as long as the uncertainties related to their position within the tumor are incorporated into the planning target volume.

ANP, BNP and D-dimer predict right ventricular dysfunction in patients with acute pulmonary embolism.

BACKGROUND: The aim of this study was to predict right ventricular dysfunction (RVD) using plasma concentration of D-dimer, pro-atrial natriuretic peptide (pro-ANP), brain natriuretic peptide (BNP), endothelin-1 (ET-1) and cardiac troponin I (TNI) in patients with pulmonary embolism (PE). METHODS: Patients suspected of PE had a ventilation/perfusion-single-photon emission-tomography (V/Q-SPECT), pulmonary multidetector computer tomography (MDCT) angiography, blood samples and ECG-gated cardiac CT performed the same day. RESULTS: Pro-ANP, BNP and D-dimer are associated with significantly elevated levels in PE patients with RVD. ROC curves demonstrated that D-dimer, pro-ANP and BNP were accurate for detection of RVD. CONCLUSION: Because measurements of cardiac biomarkers are inexpensive and easily obtained they may prove useful in the clinical diagnosis of RVD. However because of the small sample size, the results need to be confirmed in larger studies.

[SPECT combined with CT angiography yield better diagnostic accuracy of pulmonary embolism--secondary publication]. / SPECT kombineret med CT-angiografi giver bedre diagnostik af lungeemboli--sekundaerpublikation.

The aim of our study was to perform a prospective study that compared the diagnostic ability of V/Q single photon emission computer tomography (V/Q-SPECT), V/Q-SPECT combined with low-dose computed tomography (CT) and pulmonary multidetector computed tomography(MDCT)-angiography in patients suspected of having pulmonary embolism (PE) using a dedicated combined SPECT/MDCT-scanner. V/Q-SPECT in combination with low-dose CT had a sensitivity of 97% and a specificity of 100%. MDCT angiography had a sensitivity of 68% and a specificity of 100%. We conclude that V/Q-SPECT in combination with low-dose CT without contrast has an excellent diagnostic performance and should be considered the first-line imaging technique in the work-up of PE in most cases.

Correlation between coronary computed tomographic angiography and fractional flow reserve.

BACKGROUND: Coronary CT angiography (CCTA) has become an important modality to evaluate the presence of coronary artery disease. Coronary artery stenosis of intermediate severity remains a therapeutic dilemma. Measurement of fractional flow reserve (FFR) during coronary angiography is the most established technique to determine the hemodynamic severity of a coronary artery lesion. The aim of this study was to compare CCTA with FFR. METHODS: In 56 coronary artery stenoses (42 patients) we performed CCTA, quantitative coronary angiography and FFR. CCTA measurements included diameter stenosis (DS, %), area stenosis (AS, %), minimal lumen diameter (MLD, mm), minimal lumen area (MLA, mm(2)), lesion length (LL, mm), plaque volume (mm(3)) and burden (%). RESULTS: FFR averaged 0.81±0.14, and 10 lesions had an abnormal FFR (<0.75). We found significant correlations between FFR and DS (r=-0.67, p<0.001), AS (r=-0.68, p<0.001), MLD (r=0.58, p<0.001), MLA (r=0.53, p<0.001), LL (r=-0.36, p=0.02), plaque volume (r=-0.36, p=0.02) and plaque burden (r=-0.59, p<0.001). By multivariate regression analysis AS and LL were the strongest determinants of an abnormal FFR. The optimal cut-off value for AS was >73% (sensitivity 90%, specificity 80%, negative predictive value 97%, and positive predictive value 50%) and for LL >10 mm (sensitivity 60% and specificity 49%). CONCLUSION: This study demonstrates that quantitative CCTA is correlated to FFR. Using our CCTA criteria of abnormality, significant coronary artery stenoses can be ruled out with a high negative predictive value.

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

PURPOSE: Planar 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 METHODS: Consecutive 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 Kr. Patient follow-up was at least 6 months. RESULTS: A 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%. CONCLUSION: We conclude that V/Q SPECT has a superior diagnostic performance compared with planar V/Q scintigraphy and should be preferred when diagnosing PE.

Detection of pulmonary embolism with combined ventilation-perfusion SPECT and low-dose CT: head-to-head comparison with multidetector CT angiography.

UNLABELLED: 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 gamma-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.

[Computed tomography of the heart]. / Computertomografi af hjertet.

Noninvasive evaluation of the coronary arteries by multi-detector row computed tomography is a promising new alternative to conventional invasive coronary angiography. This article describes the technical background, methods, limitations and clinical applications and reviews current literature that compares the diagnostic accuracy of multi-detector row computed tomography with that of coronary angiography.

Quantitative assessment of left ventricular systolic wall thickening using multidetector computed tomography.

BACKGROUND: Multidetector computed tomography (MDCT) of the heart provides both anatomical and functional information. The objective of this study was to evaluate the accuracy of quantitative assessment of left ventricular contractile function in relation to two-dimensional transthoracic echocardiography (TTE). MATERIALS AND METHODS: Sixty-four patients with known or suspected coronary artery disease underwent ECG-gated 64-slice MDCT and TTE. Regional left ventricular contractile function was measured by percent systolic wall thickening (SWT) in 16 myocardial segments using MDCT, and compared with visual evaluation of wall motion score (WMS) by TTE. Global SWT by MDCT was calculated as the mean SWT of all myocardial segments and compared with wall motion index (WMI) by TTE. RESULTS: Eight hundred and eleven segments (81%) were classified as normokinetic, 142 (14%) as hypokinetic, 41 (4%) as akinetic and 5 (0.5%) as dyskinetic by TTE. A significant inverse linear trend was found between regional SWT by MDCT and WMS by TTE (p<0.001). Sensitivity and specificity for the identification of regional abnormalities of contractile function were 76% and 78%, respectively. A linear correlation between global SWT by MDCT and WMI by TTE was found (r=-0.8, p<0.001). Sensitivity and specificity for the identification of WMI>1.5 using global SWT was 91% and 94%, respectively. CONCLUSION: Quantification of systolic wall thickening by MDCT provides functional information, which is well correlated to visual assessment of global left ventricular contractile function by TTE.

Diagnostic sensitivity and specificity of Doppler ultrasound in rheumatoid arthritis.

OBJECTIVE: To evaluate the sensitivity and specificity of Doppler ultrasound (DUS) in diagnosing arthritis in the wrist and hands, and, if possible, to define a cutoff level for our ultrasound measures for inflammation, resistive index (RI), and color fraction. METHODS: Using DUS, 88 patients with active RA were selected for study and 27 healthy controls. A total of 419 joints were examined. The synovial vascularization was determined by color Doppler and spectral Doppler estimating the color fraction (the percentage of color pixels inside the synovium was the region of interest) and RI in wrist, metacarpophalangeal (MCP), and proximal interphalangeal (PIP) joints. Receiver-operator characteristic (ROC) curves were made for both US measures. Cutoff levels were selected from the ROC curves as the values with the optimum sensitivity and specificity. RESULTS: Analyses were carried out for small joints (MCP and PIP), wrists, and for all joints (pooled). Pooled joint analysis showed the area under the curve for both RI and color fraction was 0.84. The cutoff level for the color fraction was 0.01 and for RI 0.83. With these cutoff levels, the sensitivity and specificity for the color fraction were 0.92 and 0.73, respectively. For RI a sensitivity of 0.72 and specificity of 0.70 were found. Analysis of small joints and wrist gave very similar results. CONCLUSION: DUS may detect vascularization of the inflamed synovium with a high sensitivity and a moderate specificity with selected cutoff levels.

Optimal set-up for ultrasound guided punctures using new scanner applications: an in-vitro study.

OBJECTIVE: To investigate if US-visualisation of the needle tip echo during US-guided punctures could be improved by use of new technological applications. METHOD: an US-guided 18 G Trocar needle was inserted into targets of a puncture phantom. The punctures were performed in series of 10 using different settings of the US-scanner (GE Logic 700 Expert). At 7-cm of puncture depth the quality of the echo was tested using four different settings; normal (N), N + automatic tissue optimising (ATO), coded harmonic imaging (CHI), CHI + ATO and at 13-cm of puncture depths six different settings; N, N + ATO, coded excitation (CE), CE+ATO, CHI, CHI+ATO. In total 100 (40 + 60) images were randomly numbered and read independently by three radiologists with regard to scoring of the quality of the echoes from the needle tip, needle shaft and the target. RESULTS: US visualisation of the needle tip was significantly (P < 0.005) improved as compared to normal settings (N) when the settings of ATO and CE were used. CHI resulted in the lowest score. A high agreement between observers was registered. Similar results were registered with regard to scorings from the needle shaft and target. CONCLUSION: Not only changes of needle designs and puncture techniques can enhance echoes from the needle but also changes in the settings of the US-scanner with the use of new technological applications can improve visualisation of the needle echo.