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A Korn,
M Fenchel,
B Bender,
S Danz,
C Thomas,
D Ketelsen,
C D Claussen,
G Moonis,
B Krauss, M Heuschmid,
U Ernemann,
H Brodoefel
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ABSTRACT: INTRODUCTION: High-pitch CT angiography (CTA) is a recent innovation that allows significant shortening of scan time with volume coverage of 43 mm per second. The aim of our study was to assess this technique in CTA of the head and neck. METHODS: CTA of supra-aortic arteries was performed in 50 patients using two acquisition protocols: conventional single-source 64-slice (pitch 1.2) and high-pitch dual-source 128-slice CT (pitch 3.2). Subjective and objective image quality of supra-aortic vessel ostia as well as intra- and extra-cranial segments was retrospectively assessed by blinded readers and radiation dose compared between the two protocols. RESULTS: Conventional and high-pitch CTA achieved comparable signal-to-noise ratios in arterial (54.3 ± 16.5 versus 57.3 ± 14.8; p = 0.50) and venous segments (15.8 ± 6.7 versus 18.9 ± 8.9; p = 0.21). High-pitch scanning was, however, associated with sharper delineation of vessel contours and image quality significantly improved at the level of supra-aortic vessel ostia (p < 0.0001) as well as along the brachiocephalic trunk (p < 0.0001), the subclavian arteries (p < 0.0001), proximal common carotid arteries (p = 0.01), and vertebral V1 segments (p < 0.0001). Using the high-pitch mode, the dose-length product was reduced by about 35 % (218.2 ± 30 versus 141.8 ± 20 mGy × cm). CONCLUSIONS: Due to elimination of transmitted cardiac motion, high-pitch CTA of the neck improves image quality in the proximity of the aortic arch while significantly lowering radiation dose. The technique thus qualifies as a promising alternative to conventional spiral CTA and may be particularly useful for identification of ostial stenosis.
Neuroradiology 12/2012; · 2.82 Impact Factor
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RöFo - Fortschritte auf dem Gebiet der R 09/2012; 184(9):765-8. · 2.76 Impact Factor
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ABSTRACT: Purpose: Endovascular aneurysm repair (EVAR) can be challenging in angulated access vessels. The aim of this study was to evaluate a new wire technique for installing a buddy wire in the event of failure of simple advancing of a super stiff guide. Materials and Method: We investigated 8 patients eligible for EVAR. All patients presented with heavily kinked pelvic access and failure of primary advancing of a stiff guide wire through a placed catheter. A double wire technique with a combination of soft and stiff wires was applied to place a super stiff buddy wire. Cumulative angulation quantified by the sum of angles of the tortuous pelvic access vessels was measured in pre- and post-interventional CT as well as in angiographic studies of the EVAR procedure. Patients were followed up on by CT in the first 6 months. Results: A buddy wire could be installed in all patients (100 %) with significant straightening of the access vessel from a median cumulative angulation of 252.4 ± 38.1° before intervention to 159.4 ± 44.6° after placement of the buddy wire (p < 0.001). There was no technical failure of device passage and all stent-grafts could be deployed safely. Three cases of stenosis caused by torsion distal to the aortic stent-graft were seen after stent-graft delivery. One case of stenosis was hemodynamically relevant and was successfully stented. No major adverse events occurred within the first 6 months of follow-up. Conclusion: The new step-by-step wire technique is feasible and safe in the case of hostile pelvic vessel access, and facilitates the advancement of aortic stent-grafts in off-label patients.
RöFo - Fortschritte auf dem Gebiet der R 07/2012; 184(10):899-904. · 2.76 Impact Factor
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ABSTRACT: Die Technik der Computertomographie und damit auch der CT-Kolonographie entwickelt sich rasant.
Der aktuelle Stellenwert der CT-Kolonographie kann wie folgt zusammengefasst werden:
Die Methode stellt eine echte Alternative zur Doppelkontrastuntersuchung dar, wenn die entsprechenden technischen Voraussetzungen
gegeben sind.
Bei inkompletter Koloskopie ist eine CTC im Anschluss ohne weiteres mit sehr guten Ergebnissen durchführbar.
Die CTC kann bei der prätherapeutischen Diagnostik kolorektaler Tumoren mit einem Staging-CT des Abdomens kombiniert werden.
Die jüngsten Fortschritte bei der Bildqualität und Datenakquisition durch die Einführung der 16-Zeilen-Technologie hinsichtlich
der nochmals verbesserten räumlichen und zeitlichen Auflösung erscheinen sehr vielversprechend. Auch die Entwicklungen auf
dem Gebiet der Datennachverarbeitung können eine weitere Verbesserung v. a. hinsichtlich der zeitlichen Effektivität erbringen.
Alternative Vorbereitungsschemata zur komfortableren Darmreinigung bzw. -markierung dürften zu einer nochmals verbesserten
Akzeptanz durch die Patienten beitragen. Die Strahlenexposition ist in Low-dose-Technik noch mit der eines Kolondoppelkontrastes
vergleichbar, wenngleich sie aber durch Optimierung der Untersuchungsparameter noch gesenkt werden kann.
Der folgende Artikel soll (1) einen Überblick über den derzeitigen Status der CTC hinsichtlich Patientenvorbereitung, Bildakquisition
und Datennachbearbeitung liefern; (2) die Ergebnisse aktueller klinischer und experimenteller Studien vorstellen und (3) die
zukünftige Richtung der virtuellen Koloskopie unter Berücksichtigung der technischen Neuerungen aufzeigen.
Computertomography and with it CT-colonography evolves technically and also possibilities of data processing proceed rapidly.
The current status of CTC can be summarized as follows:
The method represents a true alternative to barium enema if technical conditions are given.
CTC can be performed with excellent results immediately following an incomplete colonoscopy.
In pretherapeutic diagnosis of colorectal carcinoma, CTC can be combined with a staging CT of the abdomen.
The recent technical advances with new 16 row technology in image quality and data acquisition – mainly concerning the spatial
and temporal resolution – are very promising. Developments in postprocessing of CT data can also contribute to a higher efficiency
of labor. Alternative preparation schemata can lead to a more comfortable bowel cleansing and stool labeling can even avoid
this procedure, resulting both in an even improved compliance. Radiation exposure in low dose technique is comparable to a
double contrast barium enema and can be still reduced by optimisation of scanning parameters.
The aim of the following article is (1 to give an overview of the current status of patient preparation, image acquisition
and data processing; (2) to review recent clinical trials and experimental studies and to show future directions of CTC with
regard to the clinical development.
Der Radiologe 04/2012; 42(9):712-721. · 0.61 Impact Factor
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ABSTRACT: In patients with peripheral artery disease, the options for interventional therapy of critical limb ischemia have increased within the last few years. Different antegrade and retrograde techniques for vascular recanalization are used to pass even complex and long stenoses or occlusions below the knee (BTK). A variety of diverse wires, catheters and stent types allows arterial recanalization of the lower leg and increases the impact of therapeutic efforts. This review article describes indications, advanced techniques as well as materials in BTK interventions and summarizes current evidence-based study results.
RöFo - Fortschritte auf dem Gebiet der R 03/2012; 184(7):607-17. · 2.76 Impact Factor
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A Korn,
M Fenchel,
B Bender,
S Danz,
T K Hauser,
D Ketelsen,
T Flohr,
C D Claussen, M Heuschmid,
U Ernemann,
H Brodoefel
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ABSTRACT: IR has recently demonstrated its capacity to reduce noise and permit dose reduction in abdominal and thoracic CT applications. The purpose of our study was to assess the potential benefit of IR in head CT by comparing objective and subjective image quality with standard FBP at various dose levels.
Ninety consecutive patients were randomly assigned to undergo nonenhanced and contrast-enhanced head CT at a standard dose (320 mAs; CTDI, 60.1) or 15% (275 mAs; CTDI, 51.8) and 30% (225 mAs; CTDI, 42.3) dose reduction. All acquisitions were reconstructed with IR in image space, and FBP and images were assessed in terms of quantitative and qualitative IQ.
Compared with FBP, IR resulted in lower image noise (P ≤ .02), higher CNR (P ≤ .03), and improved subjective image quality (P ≤ .002) at all dose levels. While degradation of objective and subjective IQ at 15% dose reduction was fully compensated by IR (CNR, 1.98 ± 0.4 at 320 mAs with FBP versus 2.05 ± 0.4 at 275 mAs with IR; IQ, 1.8 versus 1.7), IQ was considerably poorer at 70% standard dose despite using the iterative approach (CNR, 1.98 ± 0.3 at 320 mAs with FBP versus 1.85 ± 0.4 at 225 mAs with IR, P = .18; IQ, 1.8 versus 2.2, P = .03). Linear regression analysis of CNR against tube current suggests that standard CNR may be obtained until approximately 20.4% dose reduction when IR is used.
Compared with conventional FBP, IR of head CT is associated with significant improvement of objective and subjective IQ and may allow dose reductions in the range of 20% without compromising standard image quality.
American Journal of Neuroradiology 02/2012; 33(2):218-24. · 2.93 Impact Factor
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ABSTRACT: Calcifications adjacent to the vessel lumen often limit the assessment of stenoses at the carotid bifurcation in 3D multi intensity projection images (3D-MIP) using conventional single energy CT. Aim of the study was to evaluate the diagnostic value of 3D-MIP images after subtraction of bone and calcified plaques (PBS) using dual energy CT for the assessment of carotid bifurcation stenoses.
36 patients with a total of 46 stenoses at the carotid bifurcation were examined with a dual energy CT system. Grade of the stenoses and plaque morphology were assessed in axial multi planar projections (axMPR) and freely rotatable 3D-MIP images before and after PBS and compared with results from DSA.
Grade of the stenosis could be evaluated in all 46 cases in DSA, axMPR and 3D-MIP after PBS. However, in 25 cases grade of the stenosis was not assessable prior to PBS. The average grade of the stenosis increased from DSA (81.4%) to axMPR (83.5%) to 3D-MIP before and after PBS (86.5% and 85.6%). The amount of pseudo-occlusions increased in concordance with the grade of the stenosis (0<9<16). Using 3D-MIP reconstructions, plaque morphology could be evaluated in 32/46 stenoses before PBS and in 44/46 cases after PBS.
PBS facilitated the evaluation of grade of the stenosis in all cases. Nevertheless, after PBS stenoses were overrated in 3D-MIP in comparison to DSA and axMPR. Moreover, plaque morphology, as an independent risk factor for stroke, can be evaluated even in calcified plaques after PBS. Therefore dual energy CTA with plaque subtraction has the potential to identify patients with vulnerable plaques better than conventional CTA.
European journal of radiology 11/2011; 80(2):e120-5. · 2.65 Impact Factor
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RöFo - Fortschritte auf dem Gebiet der R 03/2011; 183(3):203-7. · 2.76 Impact Factor
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ABSTRACT: To estimate the effective dose of prospectively triggered computed tomography coronary angiography (CTCA) in step-and-shoot (SAS) mode, depending on the tube current and tube voltage modulation.
For dose measurements, an Alderson-Rando-phantom equipped with thermoluminescent dosimeters was used. The effective dose was calculated according to ICRP 103. Exposure was performed on a 128-slice single source scanner providing a collimation of 128 × 0.6 mm and a rotation time of 0.38 seconds. CTCA in the SAS mode was acquired with variation of the tube current (160, 240, 320 mAs) and tube voltage (100, 120, 140 kV) at a simulated heart rate of 60 beats per minute and a scan range of 13.5 cm.
Depending on gender, tube current and tube voltage, the effective dose of a CTCA in SAS mode varies from 2.8 to 10.8 mSv. Due to breast tissue in the primary scan range, exposure in the case of females showed an increase of up to 60.0 ± .4% compared to males. The dose reduction achieved by a reduction of tube current showed a significant positive, linear correlation to effective dose with a possible decrease in the effective dose of up to 60.4% (r = 0.998; p = 0.044). Disproportionately high, the estimated effective dose can be reduced by using a lower tube voltage with a dose reduction of up to 52.4%.
Further substantial dose reduction of low-dose CTCA in SAS mode can be achieved by adapting the tube current and tube voltage and should be implemented in the clinical routine, i. e. adapting those protocol parameters to patient body weight.
RöFo - Fortschritte auf dem Gebiet der R 12/2010; 182(12):1105-9. · 2.76 Impact Factor
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ABSTRACT: The study was designed as a feasibility trial to evaluate the use of GP IIb/IIIa blockade in connection with drug eluting stents, bare stents and PTA only. Sixty patients with current ulcers were randomly assigned to receive abciximab plus a sirolimus coated stent (N.=14), abciximab plus a bare stent (N.=16), abciximab plus PTA (N.=14) and PTA alone (N.=19). Angiographic control was performed at two and six months. Recanalization was successful in all cases. Two month restenosis rate was 9%, 45.5%, 67% and 46%. At six month follow-up restenosis rate was 9%, 67%, 75% and 58%, respectively; 14% of all patients had major amputations within six months. Adjunctive administration of abciximab during peripheral arterial intervention below the knee was found to be safe. Sirolimus coated stent administration was followed by a higher patency rate.
The Journal of cardiovascular surgery 04/2010; 51(2):203-12. · 1.56 Impact Factor
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C Thomas,
A Korn,
B Krauss,
D Ketelsen,
I Tsiflikas,
A Reimann,
H Brodoefel,
C D Claussen,
A F Kopp,
U Ernemann, M Heuschmid
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ABSTRACT: We sought to evaluate the feasibility and efficiency of dual energy (DE) bone and plaque removal in head and neck CT angiography.
20 patients with suspected carotid stenoses received head and neck DE-CTA as part of their pre-interventional workup. Visual grading using multiplanar reformations (MPR), thick slab maximum intensity projections (MIP) and quantitative vessel analysis (QVA) of stenoses was performed prior and after DE bone removal. Results were evaluated for the detection of relevant stenoses (vessel area reduction >70%). Vessel segmentation errors were analyzed.
Segmentation errors occurred in 19% of all vessel segments. Nevertheless, most post-bone removal artifacts could be recognized using the MPR technique for reading. Compared to MPR reading prior to bone removal, sensitivity, specificity, positive and negative predictive values after bone removal were 100%, 98%, 88% and 100% for MPR reading and 100%, 91%, 63% and 100% for exclusive MIP reading, respectively. There was a good agreement between the QVA results prior and post-DE plaque removal (r(2)=0.8858).
DE bone and plaque removal for head and neck angiography is feasible and offers a rapid and highly sensitive overview over vascular head and neck studies. Due to a slightly limited specificity of the MIP technique due to segmentation errors, possible stenoses should be verified and graded using MPR techniques.
European journal of radiology 06/2009; 76(1):61-7. · 2.65 Impact Factor
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ABSTRACT: If diagnostic imaging during pregnancy is performed, potential risks not only for the mother but also for the fetus have to be considered. Ultrasonography should be performed primarily because it is harmless for the fetus. Other imaging modalities like x-ray, computed tomography (CT) and magnetic resonance imaging (MRI) should be reserved for cases in which results of ultrasonography are inconclusive and patient care depends on further imaging. If pulmonary disease is suspected (e. g. pneumonia) chest x-ray should be performed. CT should be considered if chest x-ray is nondiagnostic or inadequate (e. g. suspicion of pulmonary embolism). In patients with abdominal symptoms the indication either for CT or MRI depends on the presumed disease. Every abdominal CT during pregnancy should include an estimation of radiation dose. Dose estimation is not necessary after CT of the chest. In case of pelvic disease in particular concerning the ovaries and the uterus as well as fetal imaging MRI is the method of choice. Contrast media should only given intravenously when a compelling clinical indication exists and the potential benefit to the patient outhweights the potential risk to the fetus.
DMW - Deutsche Medizinische Wochenschrift 05/2009; 134(14):686-9; discussion 690. · 0.53 Impact Factor
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ABSTRACT: Non-invasive assessment of plaque volume and composition is important for risk stratification and long-term studies of plaque stabilisation. Our aim was to evaluate dual-source computed tomography (DSCT) and colour-coded analysis in the quantification and classification of coronary atheroma. DSCT and virtual histology intravascular ultrasound (IVUS-VH) were prospectively performed in 14 patients. 22 lesions were compared in terms of plaque volume, maximal per cent vessel stenosis and percentages of fatty, fibrous or calcified components. Plaque characterisation was performed with software that automatically segments luminal or outer vessel boundaries and uses CT attenuation for a colour-coded plaque analysis. Good correlation was found for per cent vessel stenosis in DSCT (53+/-13%) and IVUS (51+/-14%; r(2) = 0.70). Mean volumes for entire plaque and non-calcified atheroma were 68.5+/-33 mm(3) and 56.7+/-30 mm(3), respectively, in DSCT and 60.8+/-29 mm(3) and 55.8+/-26 mm(3), respectively, in IVUS. Mean percentages of fatty, fibrous or calcified components were 28.2+/-6%, 53.2+/-9% and 18.7+/-13%, respectively, in DSCT and 29.9+/-5%, 55.3+/-12% and 14.4+/-9%, respectively, in IVUS-VH. Significant overestimation was present for the entire plaque and the volume of calcified plaque (p = 0.03; p = 0.0004). Although good correlation with IVUS was obtained for the entire plaque (r(2) = 0.76) and non-calcified plaque volume (r(2) = 0.84), correlation proved very poor and insignificant for percentage plaque composition. Interclass correlation coefficients for non-calcified plaque volume and percentages of fatty, fibrous or calcified components were 0.99, 0.99, 0.95 and 0.98, respectively, and intraclass coefficients were 0.98, 0.93, 0.98 and 0.99, respectively. We found that using Hounsfield unit-based analysis, DSCT allows for accurate quantification of non-calcified plaque. Although percentage plaque composition proves highly reproducible, it is not correlated with IVUS-VH.
The British journal of radiology 04/2009; 82(982):805-12. · 2.11 Impact Factor
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C Thomas,
O Patschan,
D Ketelsen,
I Tsiflikas,
A Reimann,
H Brodoefel,
M Buchgeister,
U Nagele,
A Stenzl,
C Claussen,
A Kopp, M Heuschmid,
H-P Schlemmer
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ABSTRACT: The efficiency and radiation dose of a low-dose dual-energy (DE) CT protocol for the evaluation of urinary calculus disease were evaluated. A low-dose dual-source DE-CT renal calculi protocol (140 kV, 46 mAs; 80 kV, 210 mAs) was derived from the single-energy (SE) CT protocol used in our institution for the detection of renal calculi (120 kV, 75 mAs). An Alderson-Rando phantom was equipped with thermoluminescence dosimeters and examined by CT with both protocols. The effective doses were calculated. Fifty-one patients with suspected or known urinary calculus disease underwent DE-CT. DE analysis was performed if calculi were detected using a dedicated software tool. Results were compared to chemical analysis after invasive calculus extraction. An effective dose of 3.43 mSv (male) and 5.30 mSv (female) was measured in the phantom for the DE protocol (vs. 3.17/4.57 mSv for the SE protocol). Urinary calculi were found in 34 patients; in 28 patients, calculi were removed and analyzed (23 patients with calcified calculi, three with uric acid calculi, one with 2,8-dihyxdroxyadenine-calculi, one patient with a mixed struvite calculus). DE analysis was able to distinguish between calcified and non-calcified calculi in all cases. In conclusion, dual-energy urinary calculus analysis is effective also with a low-dose protocol. The protocol tested in this study reliably identified calcified urinary calculi in vivo.
European Radiology 03/2009; 19(6):1553-9. · 3.22 Impact Factor
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RöFo - Fortschritte auf dem Gebiet der R 01/2009; 180(12):1031-4. · 2.76 Impact Factor
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ABSTRACT: Important oropharyngeal structures can be superimposed by metallic artifacts due to dental implants. The aim of this study was to compare the image quality of multiplanar reconstructions and an angulated spiral in dual-source computed tomography (DSCT) of the neck.
Sixty-two patients were included for neck imaging with DSCT. MPRs from an axial dataset and an additional short spiral parallel to the mouth floor were acquired. Leading anatomical structures were then evaluated with respect to the extent to which they were affected by dental artifacts using a visual scale, ranging from 1 (least artifacts) to 4 (most artifacts).
In MPR, 87.1 % of anatomical structures had significant artifacts (3.12 +/- 0.86), while in angulated slices leading anatomical structures of the oropharynx showed negligible artifacts (1.28 +/- 0.46). The diagnostic growth due to primarily angulated slices concerning artifact severity was significant (p < 0.01).
MPRs are not capable of reducing dental artifacts sufficiently. In patients with dental artifacts overlying the anatomical structures of the oropharynx, an additional short angulated spiral parallel to the floor of the mouth is recommended and should be applied for daily routine. As a result of the static gantry design of DSCT, the use of a flexible head holder is essential.
RöFo - Fortschritte auf dem Gebiet der R 12/2008; 181(1):54-9. · 2.76 Impact Factor
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ABSTRACT: To assess HU-based color mapping for characterization of coronary plaque, using intravascular ultrasound virtual histology (IVUS-VH) as a standard of reference. Dual-source computed tomography and IVUS-VH were prospectively performed in 13 patients. In five lesions, HU thresholds of the color-coding software were calibrated to IVUS-VH. In a 15-lesion verification cohort, volumes of vessel, lumen and plaque or percentages of lipid, fibrous and calcified components were obtained through use of pre-set HU cut-offs as well as through purely visual adjustment of color maps. Calibrated HU ranges for fatty or fibrous plaque, lumen and calcification were -10-69, 70-158, 159-436 and 437+. Using these cut-offs, HU-based analysis achieved good agreement of plaque volume with IVUS (47.0 vs. 51.0 mm(3)). Visual segmentation led to significant overestimation of atheroma (61.6 vs. 51.0 mm(3); P = 0.04) Correlation coefficients for volumes of vessel, lumen and plaque were 0.92, 0.87 and 0.83 with HU-based analysis or 0.92, 0.85 and 0.71 with visual evaluation. With both methods, correlation of percentage plaque composition was poor or insignificant. HU-based plaque analysis showed good reproducibility with intra-class correlation coefficients being 0.90 for plaque volume and 0.81, 0.94 or 0.98 for percentages of fatty, fibrous or calcified components. With use of optimized HU thresholds, color mapping allows for accurate and reproducible quantification of coronary plaque.
European Radiology 06/2008; 18(11):2466-74. · 3.22 Impact Factor
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ABSTRACT: The aim of this study was to assess the impact of heart rate, heart rate variability and calcification on image quality and diagnostic accuracy in an unselected patient collective.
One hundred and two consecutive patients with known or suspected coronary artery disease underwent both 64-MSCT and invasive coronary angiography. Image quality (IQ) was assessed by independent observers using a 4-point scale from excellent (1) to non-diagnostic (4). Accuracy of MSCT regarding detection or exclusion of significant stenosis (>50%) was evaluated on a per segment basis in a modified AHA 13-segment model. Effects of heart rate, heart rate variability, calcification and body mass index (BMI) on IQ and accuracy were evaluated by multivariate regression. IQ and accuracy were further analysed in subgroups of significant predictor variables and simple regression performed to calculate thresholds for adequate IQ.
Mean heart rate was 68.2+/-13.3 bpm, mean heart rate variability 11.5+/-16.0 beats per CT-examination (bpct) and median Agatston score 226.5. Average IQ score was 2+/-0.6 whilst diagnostic quality was obtained in 89% of segments. Overall sensitivity, specificity, PPV or NPV was 91.2%, 99.2%, 95.3% or 98.3%. According to multivariate regression, overall IQ was significantly related to heart rate and calcification (P=0.0038; P<0.0001). The effect of heart rate variability was limited to IQ of RCA segments (P=0.018); BMI was not related to IQ (P=0.52). Calcification was the only predictor variable with significant effect on the number of non-diagnostic segments (P<0.0001). In a multivariate regression, calcification was also the single factor with impact on diagnostic accuracy (P=0.0049).
Whilst heart rate, heart rate variability and calcification all show an inverse correlation to IQ, severe calcium burden remains the single factor with translation of such effect into decrease of diagnostic accuracy.
European Journal of Radiology 05/2008; 66(1):134-41. · 2.61 Impact Factor
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H Brodoefel,
A Reimann,
B Klumpp,
M Fenchel, M Heuschmid,
C Burgstahler,
S Schroeder,
S Miller,
C D Claussen,
A M Scheule,
A F Kopp
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ABSTRACT: The purpose was to assess 64-slice CT in the analysis of global and regional ventricular function, using a model of acute and subacute myocardial infarction in comparison with cine-MRI. Seven pigs underwent standard MSCT and MRI examination a median 1 and 21 days following creation of reperfused myocardial infarction. Endocardial and epicardial contours were manually defined and ventricular volumes calculated according to Simpson's method. Results were compared by Pearson's correlation coefficient and Blant-Altman analysis. Wall motion was assessed on cine-images and evaluated by kappa statistics. MSCT revealed a strong correlation with cine-MRI regarding quantification of end-diastolic volume (EDV; r = 0.97), end-systolic volume (ESV; r = 0.97), stroke volume (SV; r = 0.94), ejection fraction (EF; r = 0.95) or myocardial mass (MM; r =0.94 ). Minor overestimation was observed for EDV and ESV (bias -1.7 ml; -1.5 ml; P=0.095; 0.025), whilst the mean difference for EF was found to be negligible (bias 0.9%; P = 0.18). Both modalities showed a 96.2% segmental agreement in regional wall motion (weighted-kappa 0.91 for 238 segments). This was true for both acute and subacute infarct phase and MSCT, and thereby enabled accurate intraindividual follow-up of segmental dysfunction. Sixty-four-slice CT allows for reliable analysis of global cardiac function and, moreover, provides accurate evaluation of wall motion in acute and subacute myocardial infarct.
European Radiology 12/2007; 17(11):2948-56. · 3.22 Impact Factor
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ABSTRACT: The radiation exposure of four different 64-slice MDCT-colonography (CTC) protocols was evaluated using an Alderson-Rando phantom. Protocols using 30 mAs (collimation 20 x 1.2 mm), 50 mAs (collimation 20 x 1.2 and 64 x 0.6 mm) and 80 mAs (20 x 1.2 mm) representing screening low-dose, routine, narrow collimation and oncologic staging setups were measured with an Alderson-Rando phantom (Alderson Research Laboratories Inc.). Scans were performed on a 64-row MDCT (SOMATOM Sensation 64, Siemens) simulating the prone and supine positions with a constant voltage of 120 kV. Dose values (male/female) were 2.5/2.9, 3.8/4.2, 4.2/4.5 and 5.7/6.4 mSv for 30, 50 (20 x 1.2 and 64 x 0.6 mm) and 80 mAs, respectively. Measurements showed an elevated dose for females (11.5% mean; compared to males). Use of narrow collimation combined with 50 mAs resulted in a small increase of dose exposure of 10.5 (male) and 7.1% (female). Gonad doses ranged from 0.9 to 2.6 mSv (male) and from 1.5 to 3.5 mSv (female). In all protocols, the stomach wall, lower colon, urinary bladder and liver were slightly more highly exposed (all <2.3 mSv) than the other organs, and the breast dose was <0.3 mSv in every setup. Values of radiation exposure in 64- and 16-slice CTC differ only marginally when using the narrow collimation. In 64-slice CTC, the use of narrow (64 x 0.6 mm) collimation shows slightly elevated dose values compared to wider (20 x 1.2 mm) collimation.
European Radiology 10/2007; 17(10):2616-21. · 3.22 Impact Factor
