P Hein

Charité Universitätsmedizin Berlin, Berlín, Berlin, Germany

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Publications (57)106.33 Total impact

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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; · 4.34 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 09/2012; · 2.88 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 05/2012; · 0.70 Impact Factor
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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. · 2.70 Impact Factor
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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. · 2.76 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. · 4.34 Impact Factor
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    Journal of the American College of Cardiology 09/2010; 56(12):e23. · 14.09 Impact Factor
  • Rofo-fortschritte Auf Dem Gebiet Der Rontgenstrahlen Und Der Bildgebenden Verfahren - ROFO-FORTSCHR RONTGENSTRAHL. 01/2010; 182.
  • Rofo-fortschritte Auf Dem Gebiet Der Rontgenstrahlen Und Der Bildgebenden Verfahren - ROFO-FORTSCHR RONTGENSTRAHL. 01/2010; 182.
  • Rofo-fortschritte Auf Dem Gebiet Der Rontgenstrahlen Und Der Bildgebenden Verfahren - ROFO-FORTSCHR RONTGENSTRAHL. 01/2010; 182.
  • Rofo-fortschritte Auf Dem Gebiet Der Rontgenstrahlen Und Der Bildgebenden Verfahren - ROFO-FORTSCHR RONTGENSTRAHL. 01/2010; 182.
  • A Lembcke, P Hein, P Rogalla
    Rofo-fortschritte Auf Dem Gebiet Der Rontgenstrahlen Und Der Bildgebenden Verfahren - ROFO-FORTSCHR RONTGENSTRAHL. 01/2010; 182.
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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. · 4.34 Impact Factor
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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. · 4.85 Impact Factor
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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. · 0.43 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. · 2.65 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. · 4.34 Impact Factor
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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. · 2.76 Impact Factor
  • European journal of cardio-thoracic surgery: official journal of the European Association for Cardio-thoracic Surgery 03/2009; 35(4):726. · 2.40 Impact Factor
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    ABSTRACT: We sought to determine the feasibility and image quality of 320-slice volume computed tomography (CT) angiography for the evaluation of patients with acute chest pain. Thirty consecutive patients (11 female, 19 male, mean age 63.2 +/- 14.2 years) with noncritical, acute chest pain underwent 320-slice CT using a protocol consisting of a nonspiral, nongated CT of the entire chest, followed by a nonspiral, electrocardiography-gated CT study of the heart. Data were acquired following a biphasic intravenous injection of 90 ml iodinated contrast agent. Vessel attenuation values of different thoracic vascular territories were recorded, and image quality scored on a five-point scale by two readers. Mean attenuation was 467 +/- 69 HU in the ascending aorta, 334 +/- 52 HU in the aortic arch, 455 +/- 71 HU in the descending aorta, 492 +/- 94 HU in the pulmonary trunk, and 416 +/- 63 HU and 436 +/- 62 HU in the right and left coronary artery, respectively. Radiation exposure estimates ranged between 7 and 14 mSv. The CT protocol investigated enabled imaging of the thoracic aorta, coronary and pulmonary arteries with an excellent diagnostic quality for chest pain triage in all patients. This result was achieved with less contrast material and reduced radiation exposure compared with previously investigated imaging protocols.
    European Radiology 02/2009; 19(5):1148-55. · 4.34 Impact Factor