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Biomedical subjects

Bernd Hamm

Publications and source records attributed to Bernd Hamm.

At least 19 recordsLinked to original sources
PubMed2007

Multislice computed tomography: angiographic emulation versus standard assessment for detection of coronary stenoses.

The present study investigated angiographic emulation of multislice computed tomography (MSCT) (catheter-like visualization) as an alternative approach of analyzing and visualizing findings in comparison with standard assessment. Thirty patients (120 coronary arteries) were randomly selected from 90 prospectively investigated patients with suspected coronary artery disease who underwent MSCT (16-slice scanner, 0.5 mm collimation, 400 ms rotation time) prior to conventional coronary angiography for comparison of both approaches. Sensitivity and specificity of angiographic emulation [81% (26/32) and 93% (82/88)] were not significantly different from those of standard assessment [88% (28/32) and 99% (87/88)], while the per-case analysis time was significantly shorter for angiographic emulation than for standard assessment (3.4 +/- 1.5 vs 7.0 +/- 2.5 min, P < 0.001). Both interventional and referring cardiologists preferred angiographic emulation over standard curved multiplanar reformations of MSCT coronary angiography for illustration, mainly because of improved overall lucidity and depiction of sidebranches (P < 0.001). In conclusion, angiographic emulation of MSCT reduces analysis time, yields a diagnostic accuracy comparable to that of standard assessment, and is preferred by cardiologists for visualization of results.

Aged↗
PubMed2007

Coronary artery stenosis quantification using multislice computed tomography.

RATIONALE AND OBJECTIVES: Reliable noninvasive detection of stenoses with multislice computed tomography (MSCT) is feasible. This study's aim was to analyze the agreement, correlation, and reliability of MSCT with conventional coronary angiography as the reference standard for quantification of coronary artery stenoses. MATERIALS AND METHODS: A total of 118 significant (at least 50%) coronary artery stenoses with a reference vessel diameter of at least 1.5 mm in 62 patients were analyzed by MSCT using 16 detector rows (Aquilion, Toshiba, Otawara, Japan), multisegment reconstruction, and voxel sizes of 0.35x0.35x0.5 mm. The degree of stenosis on MSCT and quantitative coronary angiography (QCA) was measured by correlating the difference between the reference vessel diameter (average of 2 measurements directly proximal and distal to the stenosis) and the stenotic vessel diameter to the reference vessel diameter. RESULTS: Correlation between the percent diameter stenosis determined by MSCT (78.2+/-13.6%) and QCA (76.0+/-14.8%) was significant (P<0.001) but only moderately so (R=0.51). Bland-Altman analysis revealed no systematic under- or overestimation with MSCT but large limits of agreements (+/-27.6%). Also the limits of agreement for interobserver agreement (reliability) of MSCT data were considerably large (+/-24.8%). Among the 27 coronary artery stenoses with a reference diameter of at least 3.5 mm, there was improved correlation (R=0.80) and the limits of agreement between MSCT and QCA were significantly smaller (+/-17.3%, P<0.008). The agreement between MSCT and QCA was not significantly different for stenoses with no calcification or only calcium spots (+/-28.2%) as compared with those with moderate-or-severe calcifications (+/-27.3%; P=0.8). MSCT allowed correct classification of coronary stenoses into low-grade (below 75%) and high-grade stenoses (at least 75%), in 62% (73 of 118). CONCLUSIONS: The accuracy and reliability of coronary artery stenosis quantification with MSCT using isotropic voxel sizes and multisegment reconstruction is still too low to recommend routine clinical application because of rather low agreement, correlation, and reliability. Despite these limitations, the current results demonstrate the potential of MSCT for reliable and accurate quantification of coronary artery stenoses in the near future provided that further improvements in spatial and temporal resolution will be achieved.

Anatomy, Cross-Sectional↗
PubMed2006

Evaluation of global and regional left ventricular function with 16-slice computed tomography, biplane cineventriculography, and two-dimensional transthoracic echocardiography: comparison with magnetic resonance imaging.

OBJECTIVES: We sought to compare left ventricular (LV) function assessed with multislice computed tomography (MSCT), biplane cineventriculography (CVG), and transthoracic echocardiography (Echo), with magnetic resonance imaging (MRI) as the reference standard. BACKGROUND: With the same data as acquired for noninvasive coronary angiography, MSCT enables registration of myocardial function. METHODS: A total of 88 patients (64 men and 24 women) underwent MSCT with 16 x 0.5 mm detector collimation, CVG, and MRI, whereas Echo was retrospectively analyzed in a subset of 30 patients. RESULTS: Regarding the ejection fraction, the agreement was significantly superior for MSCT than for CVG (+/- 10.2% vs. +/- 16.8%; p < 0.001) and Echo (+/- 11.0% vs. +/- 21.2%; p < 0.001). For the end-diastolic and end-systolic volumes, the limits of agreement with CVG (p < 0.001) and Echo (p < 0.001 and p < 0.02, respectively) were also significantly larger than with MSCT. In comparison with MSCT, CVG significantly overestimated the end-diastolic and end-systolic volumes (p < 0.001). Intraobserver analysis of MSCT yielded limits of agreement for ejection fraction (+/- 4.8%), end-diastolic volume (+/- 15.6 ml) and end-systolic volume (+/- 8.0 ml), and myocardial mass (+/- 18.2 g). The accuracy in identifying patients and myocardial segments with abnormal regional function was significantly higher with MSCT (84% and 95%) than with CVG (63% and 90%; p < 0.002 and p < 0.001), whereas MSCT and Echo were not significantly different in identifying patients with abnormal regional function. CONCLUSIONS: Our results indicate that the assessment of global and regional LV function with MSCT is more accurate than with CVG, whereas MSCT is superior to Echo for global function. This suggests that MSCT allows reliable evaluation of global and regional LV function.

Aged↗
PubMed2006

Diagnostic quality and scoring of synovitis, tenosynovitis and erosions in low-field MRI of patients with rheumatoid arthritis: a comparison with conventional MRI.

OBJECTIVE: To compare dedicated low-field MRI (lfMRI) with conventional MRI (cMRI) in the detection and scoring of synovitis, tenosynovitis and erosions in patients with rheumatoid arthritis. PATIENTS AND METHODS: The wrist and finger joints of 17 patients with rheumatoid arthritis (median (range) disease duration 8 years (7-12); Disease Activity Score 3.3 (2.6-4.5)) were examined by 0.2 T lfMRI and 1.5 TcMRI. The protocols comprised coronal spin-echo and three-dimensional gradient-echo sequences before and after contrast medium administration. Synovitis of the metacarpophalangeal and proximal interphalangeal joints 2-5 and the wrist joints was scored according to Outcome Measures in Rheumatology recommendations. Tenosynovitis and erosions were scored using 4-point and 6-point scales, respectively. The results were analysed by calculating kappa values and performing McNemar's test intra-individually on a joint-by-joint basis. RESULTS: Agreement between the two MRI techniques was good to excellent for synovitis and erosions, and moderate for tenosynovitis. Of the 306 joints evaluated, 245 and 200 joints showed synovitis in lfMRI and cMRI, respectively. Scoring of synovitis of the finger joints yielded kappa values from 0.69 to 0.94. Of the 68 flexor tendons evaluated, tenosynovitis was diagnosed by lfMRI in 24 and by cMRI in 33 instances. Of the 391 bones evaluated, 154 and 139 showed erosions in lfMRI and cMRI, respectively. kappa values for erosion scores were between 0.65 and 1. CONCLUSION: Dedicated, lfMRI shows high agreement with cMRI in diagnosing and scoring synovitis, tenosynovitis and erosions in rheumatoid arthritis when using standardised scoring systems.

Adult↗
PubMed2006

Cost effectiveness of coronary angiography and calcium scoring using CT and stress MRI for diagnosis of coronary artery disease.

We compared the cost effectiveness of recent approaches [coronary angiography and calcium scoring using computed tomography (CT) and stress magnetic resonance imaging (MRI)] to the diagnosis of coronary artery disease (CAD) with those of the traditional diagnostic modalities [conventional angiography (CATH), exercise ECG, and stress echocardiography] using a decision tree model. For patients with a 10% to 50% pretest likelihood of coronary artery disease, non-invasive coronary angiography using CT was the most cost effective approach, with costs per correctly identified CAD patient of euro4,435 (10% likelihood) to euro1,469 (50% likelihood). Only for a pretest likelihood of 30% to 40% was calcium scoring using CT more cost effective than any of the traditional diagnostic modalities, while MRI was not cost effective for any pretest likelihood. At a pretest likelihood of 60%, CT coronary angiography and CATH were equally effective, while CATH was most cost effective for a pretest likelihood of at least 70%. In conclusion, up to a pretest likelihood for coronary artery disease of 50%, CT coronary angiography is the most cost-effective procedure, being superior to the other new modalities and the most commonly used traditional diagnostic modalities. With a very high likelihood for disease (above 60%), CATH is the most effective procedure from the perspective of society.

Adult↗
PubMed2006

Noninvasive detection of coronary artery stenoses with multislice computed tomography or magnetic resonance imaging.

BACKGROUND: Multislice computed tomography (CT) and magnetic resonance imaging (MRI) are the main candidates for noninvasive coronary angiography; however, multislice CT, unlike MRI, exposes patients to radiation and an iodinated intravenous contrast agent. OBJECTIVE: To compare the diagnostic accuracy of multislice CT and MRI for noninvasive detection of clinically significant coronary stenoses (> or =50%). DESIGN: Prospective intention-to-diagnose study. SETTING: Single tertiary referral center, Berlin, Germany. PATIENTS: 129 consecutive patients with suspected coronary artery disease. INTERVENTIONS: Multislice CT and MRI were both performed within a median of 1 day before conventional coronary angiography, which served as the reference standard. MEASUREMENTS: Diagnostic performance of multislice CT and MRI. RESULTS: 129 patients completed the study. Altogether, 108 patients with 430 vessels could be examined with both multislice CT and MRI and were used for analysis. In the per-patient analysis, the sensitivity of multislice CT (92% [95% CI, 82% to 96%]) was significantly higher than that of MRI (74% [CI, 61% to 83%]; P = 0.013). The sensitivity for detecting clinically significant stenoses was 82% for multislice CT and 54% for MRI (P < 0.001). Specificity and negative predictive value of multislice CT and MRI in the per-vessel analysis were 90% versus 87% (P = 0.73) and 95% versus 90% (P = 0.032), respectively. The effective radiation dose used with multislice CT (mean, 12.3 mSv [SD, 1.4]) in a consecutive subgroup of 73 patients was not significantly different from that used with diagnostic cardiac catheterization (11.4 mSv [SD, 4.8]) (P = 0.169). Most patients (74%) indicated that they would prefer multislice CT for future diagnostic imaging (P < 0.001). LIMITATIONS: This was a single-center study with 129 patients. CONCLUSIONS: In patients referred for conventional coronary angiography, multislice CT compares favorably with MRI for noninvasive detection of coronary stenoses.

Coronary Angiography↗
PubMed2006

Uterine fibroids: contrast-enhanced MR angiography to predict ovarian artery supply--initial experience.

PURPOSE: To prospectively evaluate the diagnostic performance of contrast material-enhanced magnetic resonance (MR) angiography in helping predict ovarian artery supply of uterine fibroids by using postembolization conventional aortography as the reference standard. MATERIALS AND METHODS: The protocol for the study was approved by the institutional review board, and each patient gave informed consent. Ninety consecutive women (mean age, 42.5 years; range, 33-63 years) underwent MR angiography before uterine artery embolization (UAE). The number and origin of the ovarian arteries were determined. Ovarian artery supply of fibroids was graded as very unlikely, possible, or very likely by using a scoring system based on a combination of MR angiographic findings. MR angiographic results were compared with those of conventional aortography performed after UAE in all patients and followed by selective angiography in case of a suspected ovarian artery supply of fibroids. Analysis of the association between MR angiographic grading and conventional angiography as the standard of reference was performed with a chi(2) trend test. Sensitivity and specificity, including exact 95% confidence intervals (CIs), of MR angiography were determined. RESULTS: MR angiography depicted 18 ovarian arteries (four bilateral, 10 unilateral), one with an atypical origin. Five ovarian arteries were classified as very likely; three, as possible; and 10, as very unlikely sources of arterial fibroid supply. Seven (39%) of 18 ovarian arteries detected at MR angiography were visible at conventional aortography. Fibroid supply was verified at selective angiography in five ovarian arteries in five (6%) of 90 patients. There was a strong association between MR angiographic grading and the results of conventional angiography (P = .002). Sensitivity of MR angiography in depicting ovarian artery supply (grade, possible or very likely) was 100% (five of five, 95% CI: 48%; 100%) and specificity was 77% (10 of 13, 95% CI: 46%; 95%). CONCLUSION: Contrast-enhanced MR angiography can help predict ovarian artery supply of uterine fibroids.

Adult↗
PubMed2006

Head-to-head comparison of multislice computed tomography and exercise electrocardiography for diagnosis of coronary artery disease.

AIMS: To prospectively compare multislice computed tomography (MSCT) and exercise electrocardiography (ex-ECG) for diagnosis of coronary artery disease (CAD) with conventional coronary angiography as the reference standard. METHODS AND RESULTS: A consecutive cohort of 80 patients with suspected CAD was examined with MSCT using 16 x 0.5 mm detector collimation, ex-ECG, and conventional coronary angiography according to standard protocols. Results were compared using the paired McNemar's test, the chi(2) test, and 95%CIs. Both the sensitivity and specificity of MSCT [91% (40 of 44 patients, 95%CI 78-97%) and 83% (30 of 36 patients, 95%CI 67-94%)] were significantly higher (P = 0.039 and P < 0.001) than those for ex-ECG [73% (32 of 44 patients, 95%CI 57-85%) and 31% (11 of 36 patients, 95%CI 16-48%)]. The pairwise McNemar's test showed significant differences between MSCT and ex-ECG in the overall diagnosis in patients with suspected CAD (P = 0.036). The rate of non-diagnostic examinations was not significantly (P = 0.078) different between MSCT and ex-ECG [8% (6 of 80 patients, 95%CI 3-16%) vs. 19% (15 of 80 patients, 95%CI 11-29%)]. CONCLUSION: In this consecutive cohort of patients scheduled to undergo conventional coronary angiography, the performance of MSCT for diagnosis of CAD was superior to that of ex-ECG.

Aged↗
PubMed2006

Focal liver lesions: SPIO-, gadolinium-, and ferucarbotran-enhanced dynamic T1-weighted and delayed T2-weighted MR imaging in rabbits.

PURPOSE: To compare a superparamagnetic iron oxide (SPIO), VSOP-C184, with a gadopentetate dimeglumine with regard to signal-enhancing effects on T1-weighted dynamic magnetic resonance (MR) images and with another SPIO contrast medium with regard to signal-reducing effects on delayed T2-weighted MR images. MATERIALS AND METHODS: All experiments were approved by the responsible Animal Care Committee. Twenty rabbits (five for each contrast agent and dose) implanted with VX-2 carcinoma were imaged at 1.5 T. VSOP-C184 at 0.015 and 0.025 mmol Fe/kg was compared with gadopentetate dimeglumine at 0.15 mmol Gd/kg and ferucarbotran at 0.015 mmol Fe/kg. The imaging protocol comprised a T1-weighted dynamic gradient-echo (GRE) MR before injection and at 6-second intervals for up to 42 seconds after injection and a T2-weighted turbo spin-echo MR before and 5 minutes after injection. Images were evaluated quantitatively, and contrast media were compared by using nonparametric analysis of variance. RESULTS: At dynamic T1-weighted GRE MR imaging with 0.015-mmol Fe/kg VSOP-C184, 0.025-mmol Fe/kg VSOP-C184, gadopentetate dimeglumine, and ferucarbotran, the median peak contrast-to-noise ratio (CNR) was 20.7 (25th percentile, 16.3; 75th percentile, 22.6), 24.2 (25th percentile, 19.3; 75th percentile, 28.5), 16.4 (25th percentile, 13.7; 75th percentile, 20.3), and 14.0 (25th percentile, 11.4; 75th percentile, 16.8), respectively. Both doses of VSOP-C184 yielded significantly higher CNR (P < .05) than the other two agents. At T2-weighted turbo spin-echo imaging with 0.015-mmol Fe/kg VSOP-C184, 0.025-mmol Fe/kg VSOP-C184, gadopentetate dimeglumine, and ferucarbotran, the median CNR was 15.0 (25th percentile, 13.4; 75th percentile, 21.3), 15.7 (25th percentile, 14.5; 75th percentile, 19.8), 11.3 (25th percentile, 8.2; 75th percentile, 12.2), and 15.7 (25th percentile, 12.5; 75th percentile, 22.4), respectively. There was no significant difference between VSOP-C184 and ferucarbotran; both had a significantly higher CNR than did gadopentetate dimeglumine. CONCLUSION: VSOP-C184 produces higher liver-to-tumor contrast at dynamic T1-weighted imaging than does gadopentetate dimeglumine; at delayed T2-weighted imaging, the contrast is comparable to that achieved with ferucarbotran.

Animals↗
PubMed2006

Myocardial viability: assessment with three-dimensional MR imaging in pigs and patients.

PURPOSE: To prospectively evaluate the correlation between a three-dimensional (3D) delayed enhancement magnetic resonance (MR) imaging sequence and a two-dimensional (2D) delayed enhancement MR imaging sequence for noninvasive assessment of myocardial viability in pigs and patients. MATERIALS AND METHODS: The pig and patient studies were approved by the responsible authorities, and patients gave written informed consent. MR imaging was performed by using a rapid 3D inversion-recovery balanced steady-state free precession sequence and a 2D segmented inversion-recovery fast low-angle shot sequence as the reference standard. Fourteen pigs with reperfused (n=7) or nonreperfused (n=7) myocardial infarction and 17 patients (13 men, four women; mean age, 64.9 years+/-8.6 [standard deviation]) suspected of having myocardial infarction were included. Linear regression analysis and Bland-Altman analysis were used to compare the infarction volumes. RESULTS: In 10 of the 14 pigs the induction of myocardial infarction was successful. In these pigs, altogether 81 segments with myocardial infarction were demonstrated by both MR sequences, and agreement between the two sequences for classification of transmural extent of myocardial infarction was 99.7%. The infarction volume determined by using 3D MR imaging (4.64 cm3+/-2.48) in the pigs highly correlated with that of 2D MR imaging (4.65 cm3+/-2.39, r=0.989, P<.001) and that of staining by using triphenyltetrazolium chloride (4.67 cm3+/-2.44, r=0.996, P<.001). Thirteen of the 17 patients examined showed myocardial infarction in 34 myocardial segments with both sequences, and agreement between the two sequences for classification of transmural extent of myocardial infarction was 98.6%. In the patients, the infarction volume determined with both sequences highly correlated (9.71 cm3+/-7.47 for the 3D sequence vs 10.01 cm3+/-8.04 for the 2D sequence, r=0.982, P<.001). The breath-hold time necessary for the 3D MR imaging (21.0+/-2.3 seconds) was significantly shorter than that for 2D MR imaging (188.3+/-20.2 seconds, P<.001). CONCLUSION: Myocardial infarction volumes obtained with the 3D MR imaging sequence are highly correlated and in good agreement with volumes obtained with the 2D MR imaging standard approach and reduced the acquisition time by a factor of nine.

Animals↗
PubMed2006

Pictorial review: electron beam computed tomography and multislice spiral computed tomography for cardiac imaging.

Electron beam computed tomography (EBCT) revolutionized cardiac imaging by combining a constant high temporal resolution with prospective ECG triggering. For years, EBCT was the primary technique for some non-invasive diagnostic cardiac procedures such as calcium scoring and non-invasive angiography of the coronary arteries. Multislice spiral computed tomography (MSCT) on the other hand significantly advanced cardiac imaging through high volume coverage, improved spatial resolution and retrospective ECG gating. This pictorial review will illustrate the basic differences between both modalities with special emphasis to their image quality. Several experimental and clinical examples demonstrate the strengths and limitations of both imaging modalities in an intraindividual comparison for a broad range of diagnostic applications such as coronary artery calcium scoring, coronary angiography including stent visualization as well as functional assessment of the cardiac ventricles and valves. In general, our examples indicate that EBCT suffers from a number of shortcomings such as limited spatial resolution and a low contrast-to-noise ratio. Thus, EBCT should now only be used in selected cases where a constant high temporal resolution is a crucial issue, such as dynamic (cine) imaging. Due to isotropic submillimeter spatial resolution and retrospective data selection MSCT seems to be the non-invasive method of choice for cardiac imaging in general, and for assessment of the coronary arteries in particular. However, technical developments are still needed to further improve the temporal resolution in MSCT and to reduce the substantial radiation exposure.

Animals↗
PubMed2006

Combination of free-breathing and breathhold steady-state free precession magnetic resonance angiography for detection of coronary artery stenoses.

PURPOSE: To analyze the incremental diagnostic value of a combination of two approaches (free-breathing and breathhold) vs. the sole free-breathing approach to coronary magnetic resonance angiography (CMRA) for detection of significant stenoses. MATERIALS AND METHODS: Thirty patients were consecutively included in this prospective trial. CMRA was performed on a 1.5-T MR scanner (Magnetom Sonata, Siemens) using a balanced steady-state free precession (SSFP) sequence during free-breathing (2.4 x 0.9 x 0.7 mm3). Breathholding acquisitions (3.0 x 1.5 x 0.7 mm3) were only performed in cases in which the quality of free-breathing CMRA precluded assessment. Patients with contraindications to CMRA, claustrophobia, or nonassessable images were not excluded from the assessment of diagnostic accuracy (intention-to-diagnose design). RESULTS: In 60% of all free-breathing coronary acquisitions the image quality was adequate for diagnostic assessment. For the remaining 40% of the cases, breathhold acquisitions were obtained. The sensitivity, specificity, nonassessable rate, and accuracy in identifying main coronary branches with significant stenoses using the combination of both breathing approaches and the free-breathing approach alone were 65% vs. 32%, 73% vs. 53%, 24% vs. 52%, and 71% vs. 46%, respectively (P < 0.001). CONCLUSION: In this consecutive cohort of patients, the combination of free-breathing and breathhold CMRA significantly improved diagnostic accuracy. Nevertheless, even this combination did not reach accuracies sufficient for routine clinical application.

Cohort Studies↗
PubMed2006

Respiratory-triggered MRCP applying parallel acquisition techniques.

PURPOSE: To evaluate the influence of parallel imaging on the image quality of respiratory triggered magnetic resonance cholangiopancreatography (MRCP). MATERIALS AND METHODS: A total of 30 consecutive patients underwent MRCP applying a respiratory triggered T2-weighted (T2w) turbo spin-echo (TSE) sequence without and with parallel imaging (acceleration factor of 2). Acquisition times of both sequences were recorded. Quantitative evaluation included measurement of a contour sharpness index of two segments of the pancreaticobiliary tree as well as calculation of the relative contrast between ductal structures and organ parenchyma at four different segments. The qualitative evaluation was performed by two independent radiologists who graded overall image quality, depiction of eight segments of the pancreaticobiliary tree, and the frequency of artifacts. RESULTS: The application of parallel imaging significantly (P<0.05) reduced the acquisition time of the respiratory triggered MRCP sequence by 37.7% (six minutes and two seconds+/-one minute and 26 seconds vs. three minutes and 46 seconds+/-58 seconds). The quantitative and qualitative evaluation revealed no statistically significant differences between the two sequences (P>0.05). The frequency of artifacts was at the same level for both sequences as well. CONCLUSION: The application of parallel imaging for respiratory triggered MRCP significantly reduces the acquisition time without relevant influence on image quality.

Adult↗
PubMed2006

Contrast enhancement in electron beam tomography of the heart: comparison of a monomeric and a dimeric iodinated contrast agent in 59 patients.

RATIONALE AND OBJECTIVES: The aim of the study is to determine whether intravascular time-density course and visualization of the coronary arteries differ with use of a hyperosmolar monomeric versus an iso-osmolar dimeric contrast agent in electron beam tomography (EBT) of the heart. MATERIALS AND METHODS: Fifty-nine patients underwent EBT of the coronary arteries using the monomeric ioversol or the dimeric iodixanol at the same concentration of 320 mg I/mL. Contrast volume was determined relative to body surface area and injected over 40 seconds. Intravascular time-density curves were created for quantitative analysis. For qualitative assessment, visualization of coronary arteries on axial scans and three-dimensional reconstructions was scored. Patients were matched for contrast flow, transit time, and mean pulse rate for statistical analysis. RESULTS: Ioversol produced a significantly greater increase in intravascular density for up to 30 seconds after injection (P < .01) compared with iodixanol. No difference between the two contrast media was seen in the qualitative assessment. CONCLUSION: Monomeric and dimeric contrast media differ in their time-density curves at coronary EBT, a reason for which is not apparent. Qualitative evaluation of coronary arteries is not affected by this difference.

Area Under Curve↗
PubMed2006

Real-time sonoelastography performed in addition to B-mode ultrasound and mammography: improved differentiation of breast lesions?

RATIONALE AND OBJECTIVES: The goal of the present study was to compare the sensitivity and specificity of elastography with that of B-mode ultrasound (US) and mammography. MATERIALS AND METHODS: A total of 300 patients with histologically confirmed breast lesions (168 benign, 132 malignant) were included. Evaluation was by means of the three-dimensional finite-element method. The data are color-coded and superimposed on the B-mode US scan. The images were evaluated by two independent readers. The results were compared with mammography, histology, and the data obtained by previous US investigations. Sensitivities and specificities were calculated. RESULTS: Sensitivity and specificity in the differentiation of benign and malignant lesions were 87% and 85%, respectively, for mammography and 94% and 83% for B-mode US. The two examiners were in very good agreement in their evaluation of the elastograms (kappa: 0.86). Elastography had a sensitivity of 82% and a specificity of 87%. Elastography was superior to B-mode US in diagnosing Breast Imaging Reporting and Data System (BI-RADS) 3 lesions (92% vs. 82% specificity) and in lipomatous involution (80% vs. 69% specificity). CONCLUSION: Elastography in breast lesions showed a higher specificity and a lower sensitivity in comparison with B-mode sonography. Elastography may be beneficial in BI-RADS 3 lesions and in lipomatous involution.

Adolescent↗
PubMed2006

Multisegment and halfscan reconstruction of 16-slice computed tomography for assessment of regional and global left ventricular myocardial function.

RATIONALE AND OBJECTIVES: We sought to prospectively compare multisegment and halfscan reconstruction of 16-slice computed tomography (CT) for the assessment of regional and global left ventricular myocardial function with magnetic resonance imaging (MRI) as the reference standard. MATERIALS AND METHODS: Forty-two patients underwent CT with 16 x 0.5-mm detector collimation. Electrocardiogram-gated reconstructions were generated with multisegment reconstruction (using up to 4 segments correlated with the raw data of up to 4 heartbeats) and standard halfscan reconstruction. Steady-state free-precession cine MRI was acquired within 24 hours. RESULTS: More normal myocardial segments were identified correctly with multisegment (95%, 620/656) compared with halfscan reconstruction (88%, 582/656) of CT (P < 0.001). Also, the accuracy (92% [657/714] vs. 87% [620/714]) and rate of nondiagnostic segments (0% vs. 5% [33/714]) were significantly better when using multisegment reconstruction (P < 0.001). The image quality with multisegment reconstruction was significantly superior to that achieved with halfscan reconstruction (P < 0.001). In the assessment of global left ventricular function, multisegment and halfscan reconstruction of CT showed high correlations for all parameters with MRI, whereas Bland-Altman analysis revealed smaller limits of agreement for assessment of myocardial mass with multisegment reconstruction (P = 0.025), but no significant differences between both reconstruction techniques in the measurement of left ventricular volumes as compared with MRI. CONCLUSIONS: Multisegment reconstruction of 16-detector row CT improves image quality and assessment of regional wall motion compared with standard halfscan reconstruction.

Adult↗
PubMed2006

Neointima inhibition: comparison of effectiveness of non-stent-based local drug delivery and a drug-eluting stent in porcine coronary arteries.

PURPOSE: To compare the inhibition of neointimal proliferation by using non-stent-based local drug delivery and a drug-eluting stent in porcine coronary arteries. MATERIALS AND METHODS: Experiments were conducted with permission of the animal protection committee of the local government. Paclitaxel was either dissolved in a nonionic contrast medium or coated on balloons. Stents were crimped on the coated balloons. Effectiveness was tested in 22 pigs. Two coronary stents were placed in each pig, and slight overstretch was applied. The animals were treated as follows: group A (control group), uncoated balloons, bare stents, and "plain" contrast medium; group B, same treatment as group A, but with paclitaxel in the contrast medium; group C, paclitaxel-coated balloons, with premounted bare stents and plain contrast medium; and group D, sirolimus-eluting stents, noncoated balloons, and plain contrast medium. Stenosis was assessed 4 weeks later at angiography and histomorphometry. For exploratory purposes, continuous variables of quantitative coronary angiography and histomorphometry were compared by using analysis of variance. RESULTS: Results at follow-up angiography indicated a mean of 1.00 mm +/- 0.18 (standard deviation) lumen diameter loss in the control group and 0.14 mm +/- 0.18 loss in the group treated with the paclitaxel-coated balloon (group C; P < .001). Findings at histomorphometry confirmed the effectiveness of drug delivery, with the most impressive inhibition of neointimal proliferation from coated balloons-the neointimal area was 2.4 mm2 +/- 0.3 (P < .01 vs all other groups), compared with 5.2 mm2 +/- 0.3 in group A (control group), 4.3 mm2 +/- 0.3 in group B, and 3.8 mm2 +/- 0.3 in group D. CONCLUSION: In spite of the short intima contact time, paclitaxel coated on the balloon inhibits neointimal formation in the porcine model of coronary stent placement.

Analysis of Variance↗