Patrick A Hein

Charité Universitätsmedizin Berlin, Berlín, Berlin, Germany

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Publications (44)107.24 Total impact

  • Alexander Lembcke · Herko Grubitzsch · Patrick A Hein
    European journal of cardio-thoracic surgery: official journal of the European Association for Cardio-thoracic Surgery 03/2015; DOI:10.1093/ejcts/ezv088 · 2.81 Impact Factor
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    ABSTRACT: To assess the effect of lower volumes of contrast medium (CM) on image quality in high-pitch dual-source computed tomography coronary angiography (CTCA). One-hundred consecutive patients (body weight 65-85 kg, stable heart rate ≤65 bpm, cardiac index ≥2.5 L/min/m(2)) referred for CTCA were prospectively enrolled. Patients were randomly assigned to one of five groups of different CM volumes (G30, 30 mL; G40, 40 mL; G50, 50 mL; G60, 60 mL; G70, 70 mL; flow rate 5 mL/s each, iodine content 370 mg/mL). Attenuation within the proximal and distal coronary artery segments was analysed. Mean attenuation for men and women ranged from 345.0 and 399.1 HU in G30 to 478.2 and 571.8 HU in G70. Mean attenuation values were higher in groups with higher CM volumes (P < 0.0001) and higher in women than in men (P < 0.0001). The proportions of segments with attenuation of at least 300 HU in G30, G40, G50, G60 and G70 were 89 %, 95 %, 98 %, 98 % and 99 %. CM volume of 30 mL in women and 40 mL in men proved to be sufficient to guarantee attenuation of at least 300 HU. In selected patients high-pitch dual-source CTCA can be performed with CM volumes of 40 mL in men or 30 mL in women. • High-pitch dual-source coronary angiography is feasible with low contrast media volumes. • Traditional injection rules still apply: higher volumes result in higher enhancement. • The patient's gender is a co-factor determining the level of contrast enhancement. • Volumes can be reduced down to 30-40 mL in selected patients.
    European Radiology 08/2013; 24(1). DOI:10.1007/s00330-013-2988-6 · 4.34 Impact Factor
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    ABSTRACT: Twin reversed arterial perfusion sequence is a rare anomaly of monochorionic multiple pregnancies affecting 1 of 35,000 pregnancies and 1% of monochorionic twin pregnancies. In this condition the affected twin has lethal malformations including poor or absent heart development and is reversely perfused by a structurally normal co-twin. We report a case of a 21-year-old woman with a monochorionic twin pregnancy affected by twin reversed arterial perfusion sequence. This case highlights the therapeutic options and the management by radiofrequency ablation, which has been shown to be an easy and reliable technique with a high success rate compared with technically demanding fetoscopic procedures. © 2012 Wiley Periodicals, Inc. J Clin Ultrasound, 2012.
    Journal of Clinical Ultrasound 05/2013; 41(4). DOI:10.1002/jcu.21932 · 0.80 Impact Factor
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    ABSTRACT: We visualized extreme ranges of motion of the hip and located femoroacetabular impingement (FAI) and subluxations using 4dimensional (D) volume computed tomography (CT). In dynamic 4D CT, 30 patients with hip pain (>3 months) and positive clinical and radiological signs of impingement were prospectively analyzed. The investigations were performed in flexion, abduction, and external rotation. The accuracy of the CT visualization of FAI was compared with the intraoperative findings during surgical dislocation, which served as the gold standard. Compared to the intraoperative visualization of FAI, the dynamic CT images showed a high degree of accuracy. 4D CT is a suitable method to dynamically visualize the functional consequences of anatomical FAI pathologies. The location of impingement can be accurately determined, and when combined with information about possible labral tears and chondral damage supplied by magnetic resonance arthrography, allows the surgeon to select the optimal surgical access and plan the required operation for minimal invasiveness. © 2012 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res.
    Journal of Orthopaedic Research 02/2013; 31(2). DOI:10.1002/jor.22224 · 2.97 Impact Factor
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    ABSTRACT: PURPOSE To evaluate the feasibility and accuracy of 320-row detector computed tomography (CT) for measuring left ventricular (LV) dimensions and function at a radiation exposure of about 1 mSv. METHOD AND MATERIALS A total of 23 patients (14 men, age 60.3±13.7 years, body weight 81.1±15.1 kg) underwent a contrast enhanced 320-row detector CT (AquilionOne, Toshiba, Japan). A dynamic volume data set of the entire heart was acquired during a single beat using following parameters: 100 kV tube voltage, 100 mA tube current, 350 ms rotation time and 200x0.5 or 240x0.5 mm collimation (z-axis coverage of 10 and 12 cm, respectively). A data set with 20 phases (in 5 % steps throughout the RR-interval) was created and analyzed on an offline workstation. Multiplanar reformations along the long and short heart axis were generated with 8 mm thickness. Using the implemented software end-diastolic, end-systolic and stroke volumes (EDV, ESV, SV), ejection fraction (EF) and myocardial mass (MM) were determined. Effective radiation dose was estimated using the dose-length-product displayed on the scanner. Magnetic resonance imaging was performed within 2 days and served as standard of truth. RESULTS Calculated radiation dose was 0.92±0.27 mSv (range 0.56-1.32 mSv). All data sets had sufficient image quality allowing a clear delineation of the myocardial borders. Comparison between CT and MRI revealed no significant differences for EDV, ESV, SV and EF (127.0±52.3 vs. 133.5±41.4 ml, 58.6±49.2 vs. 59.9±41.3 ml, 68.3±27.4 vs. 73.7±24.6 ml, 59.1±19.3 vs. 58.2±17.1 %, each with p>0.05) whereas a small bias was found for MM (135.3±33.2 vs. 127.6±32.5 g, p<0.05). Correlation coefficients for EDV, ESV, SV, EF and MM were r=0.84, r=0.93, r=0.81, r=0.94, and r=0.94, respectively (each with p<0.05). Limits of agreement for EDV, ESV, SV, EF and MM were +49.6/-62.8 ml,+37.3/-39.9 ml, +26.5/-37.1 ml,+13.2/-11.6 %, and +30.2/-14.8 g, respectively. For all parameters intra- and interobserver variability did not differ significantly between CT and MRI. CONCLUSION Dedicated CT scan techniques dramatically reduce the radiation exposure in functional cardiac imaging while maintaining a high measuring accuracy. CLINICAL RELEVANCE/APPLICATION A low radiation exposure may facilitate the acceptance of CT as additional modality for assessing LV function, especially in patients with poor sonication conditions.
    Radiological Society of North America 2011 Scientific Assembly and Annual Meeting; 12/2011
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    ABSTRACT: To investigate a single-acquisition computed tomographic angiography (CTA) protocol using a prebolus injection technique to visualize the stent-graft lumen and endoleak after endovascular aneurysm repair (EVAR). Of 162 EVAR patients referred for CTA over a 2-year period, 18 (15 men; mean age 66.4 years) with an endoleak met the study inclusion criteria, which included constant endoleak size and scans using 3 different CT protocols at least once during follow-up: monophasic CTA (C1), biphasic CTA (C2.1 and C2.2), and single-acquisition CTA using a prebolus (PB). All CTA examinations were performed with the same overall volume of contrast medium (120 mL) and were started manually using a bolus-tracking technique. Attenuation was measured within the aortic lumen proximal to the stent prosthesis (Ao) and within the endoleak itself (EL). Mean attenuation ranged between 200 (C2.2) and 313 HU (C2.1) within Ao and between 172 (C2.2) and 235 HU (C2.1) within the endoleak. The attenuation differences between Ao (C1) and Ao (PB), as well as between Ao (C2.1) and Ao (PB), were not statistically significant, while the attenuations of Ao (C2.2) and Ao (PB) differed significantly (p<0.001), with higher attenuation in PB. Compared to EL (PB), none of the mean EL attenuation values (C1, C2.1, and C2.2) differed significantly. This prebolus CTA protocol combines late-phase attenuation of a biphasic image acquisition protocol for endoleak visualization with high opacification of the stent lumen without exposing the patient to radiation twice.
    Journal of Endovascular Therapy 12/2011; 18(6):771-8. DOI:10.1583/11-3489.1 · 3.59 Impact Factor
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    ABSTRACT: PURPOSE To evaluate the effect of reduced volumes of contrast material (CM) on image quality for dynamic computed tomography (CT) imaging of the aortic valve in patients with valvular stenosis and impaired renal function. METHOD AND MATERIALS A total of 21 high-risk patients (9 men, age 72.4±6.6 years, body weight 74.8±11.2 kg) with known aortic valve stenosis and several co-morbidities were referred to a cardiac CT prior to transcatheter aortic valve implantation. All patients had a normal ventricular function. A dynamic volume data set of the heart was acquired during a single beat using the following parameters: 100 kV tube voltage, 550 mA tube current, 350 ms rotation time and 320x0.5 collimation (resulting in a z-axis coverage of 16 cm). In each patient a CM bolus with a volume corresponding to 92.5 mg iodine (Iopromid, Ultravist 370, Bayer-Schering Pharma, Germany) per kg body weight was injected over 5 seconds. Scanning was started instantly after arriving of the CM bolus in the left ventricle using bolus tracking. A data set with 20 phases (in 5 % steps throughout the RR-interval) was created and analyzed on an offline workstation using multiplanar reformations of the aortic valve complex. Aortic valve area (AVA) was determined panimetrically. Transthoracic and transesophageal echocardiography (TTE, TEE) served as references. RESULTS All data sets had adequate image quality allowing a sufficient delineation of the aortic valve cusps. The injected CM volume was on average 19.2±2.8 ml with a range of 15-23 ml. Mean attenuation in the aortic root was 245.5±56.4 HU ranging between 182 and 341 HU. Contrast-to-noise ratio was on average 10.2±3.1 with a range of 5.1-16.9. The AVA on CT (0.79±0.17cm2) was not significantly different from TEE (0.80±0.21 cm2; p>0.05) but and slightly larger than TTE (0.71±0.18 cm2; p<0.05). A close correlation was found between CT and TTE (r=0.86, p<0.05) as well as CT and TEE (r=0.78, p<0.05). Limits of agreement between modalities were in an acceptable range. . CONCLUSION Dedicated CT scan protocols permit a significant reduction of CM volumes for assessing aortic valve stenosis severity without deteriorating measuring accuracy. CLINICAL RELEVANCE/APPLICATION Examination protocols with very low CM volumes may facilitate the use of CT as an additional diagnostic tool in patients with suspected aortic valve stenosis and high risk for CM-induced nephropathy.
    Radiological Society of North America 2011 Scientific Assembly and Annual Meeting; 11/2011
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    ABSTRACT: To retrospectively evaluate the quality and complications of CT-guided biopsies and their impact on treatment. A total of 265 CT-guided interventions performed during a 6-month period were extracted by digital database query. These included 127 CT-guided biopsies, which were classified by patient age, organ/body area, histopathological biopsy diagnosis, complications, and performing physician. In 51 % of cases (65 / 127), CT-guided biopsies led to a malignant diagnosis and a change in the patient's treatment. Retrospectively, complications were to be expected in a range of 12 - 26 %, given a 95 % confidence interval. In terms of organ/body area, most complications occurred in lung biopsies (23 / 56; 41 %). 80 % of CT-guided biopsies were performed without complications. 2 of the 11 physicians performed 66 % of all biopsies (84 / 127) and had significantly fewer complications than the others. Patient age was a statistically significant factor for complications (p < 0.018) as well as for a malignant biopsy diagnosis (p < 0.009). Our initial quality control assessment suggests that frequent use of CT-guided biopsy by the performing physician rather than the general level of experience is associated with fewer complications for patients. Age is a significant factor for complications of CT-guided biopsies, thus leading to an increased risk/benefit ratio. As expected, age also significantly increases the risk of a malignant biopsy result. Complications and malignant biopsy results were not significantly associated. CT-guided biopsies triggered a change in treatment in over 50 % of cases.
    RöFo - Fortschritte auf dem Gebiet der R 08/2011; 183(9):842-8. DOI:10.1055/s-0031-1281594 · 1.96 Impact Factor
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    ABSTRACT: To investigate image quality of triple-rule-out (TRO) computed tomography (CT) using a 320-row-detector CT system with substantially reduced contrast medium volume at 100 kV. Forty-six consecutive patients with noncritical, acute chest pain underwent 320-row-detector CT using a two-step TRO protocol consisting of a non-spiral, non-gated chest CT acquisition (150 mA) followed by a non-spiral, electrocardiography-gated cardiac acquisition (200-500 mA based on body mass index (BMI)). Data were acquired using a biphasic injection protocol with a total iodinated contrast medium volume of 60 ml (370 mg/ml). Vessel attenuation and effective doses were recorded. Image quality was scored independently by two readers. Mean attenuation was 584 ± 114 Hounsfield units (HU) in the ascending aorta, 335 ± 63HU in the aortic arch, 658 ± 136HU in the pulmonary trunk, and 521 ± 97HU and 549 ± 102HU in the right and left coronary artery, respectively. In all but one patient, attenuation and image quality allowed accurate visualization of the pulmonary arteries, thoracic aorta, and coronary arteries in a single examination. Ninety-six percent of all coronary artery segments were rated diagnostic. Radiation exposure ranged between 2.0 and 3.3 mSv. Using 320-row-detector CT the investigated low-dose TRO protocol resulted in excellent opacification and image quality with substantial reduction of contrast medium volume compared to recently published TRO protocols.
    European Radiology 02/2011; 21(7):1416-23. DOI:10.1007/s00330-011-2088-4 · 4.34 Impact Factor
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    ABSTRACT: PURPOSE To investigate a monophasic computed tomography angiography (CTA) protocol using a pre-bolus injection technique in order to visualize stent graft lumen and endoleak after aortic endovascular aneurysm repair (EAR). METHOD AND MATERIALS Out of 162 patients referred for CTA after aortic endovascular aneurysm repair over a 2 year time period including 62 patients with presence of an endoleak, 18 patients (mean age 66.4; min 47, max 81; 15 men, 3 women) met the following study inclusion criteria: Constant endoleak size and all of the CT protocols were used at least once during follow-up imaging: A monophasic (C1) and a biphasic (C2.1 and C2.2; second acquisition after 30 seconds) CTA, each with single bolus injection of 120 mL contrast medium, as well as a single acquisition CTA using a pre-bolus (PB; 60 mL) followed by injection of further 60 mL contrast medium after 60 seconds delay. In all CTA examinations the same contrast material (350 mmol/L iodine) was injected at a flow rate of 3.5 mL/s. All CTA scans were started manually using a bolus tracking technique. Attenuation was measured using a region of interest within the aortic lumen proximal to the stent prosthesis (Ao) and within the endoleak itself (EL). RESULTS Mean attenuation within Ao ranged between 200 HU (C2.2) and 313 HU (C2.1) and within EL between 172 HU (C2.2) and 235 HU (C2.1). Attenuation difference between Ao (C1) and Ao (PB) as well as between Ao (C2.1) and Ao(PB) was not statistically significant. Attenuation between Ao(C2.2) and Ao(PB) differed significantly (t-test; p = .0004) with greater HU values for PB. Attenuation between EL (C1), EL (C2.1) and EL (C2.2) each compared to EL (PB) was not statistically significant. The attenuation difference between Ao and EL was largest in PB (mean 90 HU), followed by C1, C2.1 and C2.2 (mean HU 81, 78 and 28, respectively), reaching statistical significance solely for the comparison of protocol PB vs. C2.2. (p = .0027). CONCLUSION The investigated pre-bolus CTA protocol after aortic EAR combines late phase attenuation of a biphasic image acquisition protocol for endoleak visualization and concomitant high opacification of the stent lumen without exposing the patient to radiation twice, due to single phase scanning. CLINICAL RELEVANCE/APPLICATION CT units using a biphasic CTA protocol for follow-up of constant size endoleaks after aortic EAR may consider using a pre-bolus protocol instead.
    Radiological Society of North America 2010 Scientific Assembly and Annual Meeting; 11/2010
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    Maximilian de Bucourt · Patrick A Hein · Patrik Rogalla
    Journal of the American College of Cardiology 09/2010; 56(12):e23. DOI:10.1016/j.jacc.2009.11.106 · 15.34 Impact Factor
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    ABSTRACT: PURPOSE To determine the radiation dose and to evaluate the image quality of 320-slice dynamic volume CT in children. METHOD AND MATERIALS 39 patients (1 day–14 years, mean: 2.1 years, median: 0.8 years) underwent a dynamic volume CT (Toshiba Aquilion One). The scan parameters wer as follows: 80 kV for scans follwing intravenous contrast material injection, 120 kV in non-contrast scans, 10-50 mA, 0.35 to 0.5s gantry rotation time, 1-3 rotation acquisition. The formula (body weight in [kg]+5) x f was used for mAs calculation with f=1 for chest and 1.5 for abdominal scans at 120 kV. For 80 kV scans, the mAs-value was multiplied by a factor of 2.5. In non-cooperative patients and patients not able to hold their breath, 3 rotations at 0.35 s were acquired to shift the reconstruction within the acquisition window for motion artifact reduction. All scans were evaluated in respect to image quality on a scale of 1-3 (1= poor, 3=good), the resulting radiation dose was calculated based on the DLP displayed on the patient dose report and veryfied using commercially available software for dose calculation in CT (CT-Expo). RESULTS 16 cm detector coverage sufficed for scanning of the target area with exception of four patients (two chest, two abdominal scans). None of the scans was rated poor, one patient moved despite manual fixation so that a repeat scan was deemed necessary. Despite continuous respiratory motion in 10 patients, axial slices were rated as good, in one patient, motion blur was rated relevant but did not hinder diagnosis. Radiation exposure (calculated by both methods) ranged from 0.2 to 2.3 mSv, depending on the scanning area and parameters used. CONCLUSION Although no intraindividual comparison to helical CT was performed, 320-slice dynamic volume CT carries the potential for dose reduction in the pediatric patient population without the penalty of poor image quality. Motion artifacts rarely occur. CLINICAL RELEVANCE/APPLICATION 320-slice non-helical CT represents a further advancement to reduce radiation dose in pediatric CT scanning.
    Radiological Society of North America 2009 Scientific Assembly and Annual Meeting; 12/2009
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    ABSTRACT: To compare the intra- and interobserver variability of diameter and semiautomated volume measurements of brain metastases on contrast-enhanced magnetic resonance imaging (CE-MRI) data. About 75 MRI staging examinations of patients with metastasized renal cell carcinoma, thyroid cancer, or malignant melanoma (mean age, 56 years; range, 40-75 years) were included. Patients had been examined with a routine MRI protocol, including a CE 3D T1-weighted MP-RAGE sequence (1-mm slice thickness). MRI data were retrospectively analyzed using the OncoTREAT segmentation system (MeVis, Bremen, Germany, version 1.6). Volume of 355 enhancing brain metastases included in the analysis as well as the largest diameter according to Response Evaluation Criteria for Solid Tumors were measured by 2 radiologists. Intra- and interobserver variability was calculated. Metastases (n = 355) had a mean diameter of 12.2 mm (range, 3.4-44.3 mm) and a mean volume of 1.4 cm(3) (range, 12-25.1 cm(3)). With respect to interobserver variability analysis revealed broader limits of agreement for response evaluation criteria for solid tumor measurements of all lesions (range, +/-27.8%-+/-33.0%; unsigned mean: 0.2%-2.5%) than for volume measurements (range, +/-21.4%-+/-23.3%; unsigned mean, 0.1%-0.3%) with statistically significant differences between diameter and volume measurements (P <or= 0.001). Limits of agreement were similar for intra- and interobserver comparisons. Semiautomated segmentation of brain metastases on the basis of CE-MRI yielded reproducible volume measurements with a lower variability compared with linear measurements. Volumetry of contrast-enhancing brain metastases appears to be a suitable method for size determination in oncologic follow-up imaging.
    Investigative radiology 12/2009; 45(1):49-56. DOI:10.1097/RLI.0b013e3181c02ed5 · 4.45 Impact Factor
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    ABSTRACT: To assess reduced volumes of contrast agent on image quality for coronary computed tomography angiography (CCTA) by using single-beat cardiac imaging with 320-slice CT. Forty consecutive male patients (mean age: 55.8 years) undergoing CCTA with body weight <or=85 kg, heart rate <or=65 bpm, and ejection fraction >or=55% were included. Image acquisition protocol was standardized (120 kV, 400 mA, and prospective ECG-triggered single-beat nonspiral CCTA). Patients were randomly assigned to one of four groups (G1: received 40 ml, G2: 50 ml, G3: 60 ml, G4: 70 ml). Groups were compared with respect to aortic attenuation, image noise, and image quality. CT values (mean +/- standard deviation) in the aortic root were measured as 423 +/- 38 HU in G1, and 471 +/- 68, 463 +/- 60, and 476 +/- 78 HU in G2-4, respectively. There were no statistically significant differences in attenuation among the groups (P > 0.068). All 40 CT datasets were rated diagnostic, and image noise and image quality were not statistically different among groups. Using 320-slice volume CT, diagnostic image quality can be achieved with 40 ml of contrast material in CCTA in patients with normal body weight, cardiac function, and low heart rate.
    European Radiology 12/2009; 20(6):1337-43. DOI:10.1007/s00330-009-1692-z · 4.34 Impact Factor
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    ABSTRACT: PURPOSE To determine whether ultra-low dose CT (ULD-CT) can replace conventional abdominal X-ray for evaluation of the acute abdomen. METHOD AND MATERIALS 54 consecutive patients who presented to the emergency room with acute abdomen where prospectively enrolled (IRB approved). Three indications were accepted for performing ULD-CT of the abdomen (Toshiba Aquilion 16/64, 120 kV, 10-40 mA, dose modulation, 0.5 mm slice thickness): rule out bowel obstruction (G1), hollow organ perforation (G2), and urolithiasis (G3). Two blinded readers from two institutions (15 years of experience each) evaluated axial, coronal, and sagittal reconstructions, categorized findings and/or gave a free text diagnosis, rated image quality (1=excellent to 10=insufficient) and diagnostic confidence (1 =sure to 10=unsure), gave a binary answer on whether a further study would be needed and whether ULD-CT could replace abdominal X-ray. Comparison was made using Fisher’s exact and paired T-test. Confirmation of final diagnosis was: surgery, biopsy, stone extraction, standard-dose CT, and/or respective laboratory values. Radiation dose was recorded. RESULTS 10 patients had normal findings, 11 had G1, 9 had G2, and 12 had G3. Except for disagreement in one patient (reader 1: G2, reader 2: G1, final surgical diagnosis: post-operative adhesions), all other diagnoses were in agreement and correct. For reader 1 and 2, sensitivity, PPV, NPV, mean image quality and confidence level, suggested further study, and replacement of X-ray were 0.98/1.0, 1.0/1.0, 0.91/1.0, 3.1/2.6 and 1.9/1.6 (both p<0.02), 10/5 (p=0.26), and 54/54, respectively. Relevant (correct) incidental findings were noted in 12 patients by both readers. Radiation dose varied between 0.3 and 0.9 mSv. CONCLUSION Ultra-low dose CT of the abdomen with a dose profile comparable to abdominal X-ray may serve as a diagnostic replacement for conventional X-ray in specific indications. CLINICAL RELEVANCE/APPLICATION Ultra-low dose CT carries the potential to replace conventional abdominal X-ray in specific emergency indications.
    Radiological Society of North America 2009 Scientific Assembly and Annual Meeting; 12/2009
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    ABSTRACT: We sought to compare the performance of 3 computer-aided detection (CAD) polyp algorithms in computed tomography colonography (CTC) with fecal tagging. CTC data sets of 33 patients were retrospectively analysed by 3 different CAD systems: system 1, MedicSight; system 2, Colon CAD; and system 3, Polyp Enhanced View. The polyp database comprised 53 lesions, including 6 cases of colorectal cancer, and was established by consensus reading and comparison with colonoscopy. Lesions ranged from 6-40 mm, with 25 lesions larger than 10 mm in size. Detection and false-positive (FP) rates were calculated. CAD systems 1 and 2 could be set to have varying sensitivities with higher FP rates for higher sensitivity levels. Sensitivities for system 1 ranged from 73%-94% for all lesions (78%-100% for lesions > or =10 mm) and, for system 2, from 64%-94% (78%-100% for lesions > or =10 mm). System 3 reached an overall sensitivity of 76% (100% for lesions > or =10 mm). The mean FP rate per patient ranged from 8-32 for system 1, from 1-8 for system 2, and was 5 for system 3. At the highest sensitivity level for all polyps (94%), system 2 showed a statistically significant lower FP rate compared with system 1 (P = .001). When analysing lesions > or =10 mm, system 3 had significantly fewer FPs than systems 1 and 2 (P < .012). Standalone CTC-CAD analysis in the selected patient collective showed the 3 systems tested to have a variable but overall promising performance with respect to sensitivity and the FP rate.
    Canadian Association of Radiologists Journal 12/2009; 61(2):102-8. DOI:10.1016/j.carj.2009.10.005 · 0.58 Impact Factor
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    ABSTRACT: We sought to determine the comparability of multislice computed tomography (MSCT) and magnetic resonance imaging (MRI) for measuring the aortic valve orifice area (AVA) and grading aortic valve stenosis. Twenty-seven individuals, among them 18 patients with valvular stenosis, underwent AVA planimetry by both MSCT and MRI. In the subset of patients with valvular stenosis, AVA was also calculated from transthoracic Doppler echocardiography (TTE) using the continuity equation. There was excellent correlation between MSCT and MRI (r = 0.99) and limits of agreement were in an acceptable range (± 0.42 cm(2)) although MSCT yielded a slightly smaller mean AVA than MRI (1.57 ± 0.83 cm(2) vs. 1.67 ± 0.98 cm(2), p < 0.05). However, in the subset of patients with valvular stenosis, the mean AVA was not different between MSCT and MRI (1.05 ± 0.30 cm(2) vs. 1.04 ± 0.39 cm(2); p > 0.05). The mean AVAs on both MSCT and MRI were systematically larger than on TTE (0.88 ± 0.28 cm(2), p < 0.001 each). Using an AVA of 1.0 cm(2) on TTE as reference, the best threshold for detecting severe-to-critical stenosis on MSCT and MRI was an AVA of 1.25 cm(2) and 1.30 cm(2), respectively, resulting in an accuracy of 96% each. Our study specifies recent reports on the suitability of MSCT for quantifying AVA. The data presented here suggest that certain methodical discrepancies of AVA measurements exist between MSCT, MRI and TTE. However, MSCT and MRI have shown excellent correlation in AVA planimetry and similar accuracy in grading aortic valve stenosis.
    European journal of radiology 09/2009; 77(3):426-35. DOI:10.1016/j.ejrad.2009.08.014 · 2.16 Impact Factor
  • PA Hein · P Rogalla · C Klessen · A Lembcke · V C Romano
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    ABSTRACT: To evaluate the impact of dose reduction on the performance of computer-aided lung nodule detection systems (CAD) of two manufacturers by comparing respective CAD results on ultra-low-dose computed tomography (ULD-CT) and standard dose CT (SD-CT). Multi-slice computed tomography (MSCT) data sets of 26 patients (13 male and 13 female, patients 31 - 74 years old) were retrospectively selected for CAD analysis. Indication for CT examination was staging of a known primary malignancy or suspected pulmonary malignancy. CT images were consecutively acquired at 5 mAs (ULD-CT) and 75 mAs (SD-CT) with 120 kV tube voltage (1 mm slice thickness). The standard of reference was determined by three experienced readers in consensus. CAD reading algorithms (pre-commercial CAD system, Philips, Netherlands: CAD-1; LungCARE, Siemens, Germany: CAD-2) were applied to the CT data sets. Consensus reading identified 253 nodules on SD-CT and ULD-CT. Nodules ranged in diameter between 2 and 41 mm (mean diameter 4.8 mm). Detection rates were recorded with 72 % and 62 % (CAD-1 vs. CAD-2) for SD-CT and with 73 % and 56 % for ULD-CT. Median false positive rates per patient were calculated with 6 and 5 (CAD-1 vs. CAD-2) for SD-CT and with 8 and 3 for ULD-CT. After separate statistical analysis of nodules with diameters of 5 mm and greater, the detection rates increased to 83 % and 61 % for SD-CT and to 89 % and 67 % for ULD-CT (CAD-1 vs. CAD-2). For both CAD systems there were no significant differences between the detection rates for standard and ultra-low-dose data sets (p > 0.05). Dose reduction of the underlying CT scan did not significantly influence nodule detection performance of the tested CAD systems.
    RöFo - Fortschritte auf dem Gebiet der R 06/2009; 181(11):1056-64. DOI:10.1055/s-0028-1109394 · 1.96 Impact Factor
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    ABSTRACT: The purpose of this study was to evaluate a whole-organ perfusion protocol of the pancreas in patients with primary pancreas carcinoma and to analyse perfusion differences between normal and diseased pancreatic tissue. Thirty patients with primary pancreatic malignancy were imaged on a 320-slice CT unit. Twenty-nine cancers were histologically proven. CT data acquisition was started manually after contrast-material injection (8 ml/s, 350 mg iodine/ml) and dynamic density measurements in the right ventricle. After image registration, perfusion was determined with the gradient-relationship technique and volume regions-of-interest were defined for perfusion measurements. Contrast time-density curves and perfusion maps were generated. Statistical analysis was performed using the Kolmogorov-Smirnov test for analysis of normal distribution and Kruskal-Wallis test (nonparametric ANOVA) with Bonferroni correction for multiple stacked comparisons. In all 30 patients the entire pancreas was imaged, and registration could be completed in all cases. Perfusion of pancreatic carcinomas was significantly lower than of normal pancreatic tissue (P < 0.001) and could be visualized on colored perfusion maps. The 320-slice CT allows complete dynamic visualization of the pancreas and enables calculation of whole-organ perfusion maps. Perfusion imaging carries the potential to improve detection of pancreatic cancers due to the perfusion differences.
    European Radiology 06/2009; 19(11):2641-6. DOI:10.1007/s00330-009-1453-z · 4.34 Impact Factor
  • European journal of cardio-thoracic surgery: official journal of the European Association for Cardio-thoracic Surgery 03/2009; 35(4):726. DOI:10.1016/j.ejcts.2008.12.012 · 2.81 Impact Factor