Mathias Langer - Academia.edu (original) (raw)
Papers by Mathias Langer
RöFo - Fortschritte auf dem Gebiet der R
The capabilities of a patient-oriented digital optical laser-card for the documentation of the im... more The capabilities of a patient-oriented digital optical laser-card for the documentation of the image/report unit and for image transmission were assessed. 150 conventional X-rays covering the fields of urology (n = 50), traumatology (n = 50) and orthopaedics (n = 50) were digitised using a CCD scanner and subsequently transmitted to an Image-Transfer Medium (ITM) and to an optical laser-card. The image quality for the detection of relevant diagnostic parameters was evaluated by 4 radiologists and one clinician of the corresponding specialty. Based upon a total of 4740 decision readings for each method, it was found that the optical laser-card reduced the image quality significantly (p < 0.01) in comparison to the digitised ITM images in all fields. Thus, a primary diagnostic statement cannot be made based upon the images of the optical card. However, concomitant documentation of the image and opinion on the card may be used for the transmission of the radiological report, especially to external referring institutions.
European heart journal, Jan 7, 2015
We sought to evaluate the frequency of early hypo-attenuated leaflet thickening (HALT) of the SAP... more We sought to evaluate the frequency of early hypo-attenuated leaflet thickening (HALT) of the SAPIEN 3 transcatheter aortic valve (S3). Of 249 patients who had undergone S3 implantation, we studied 156 consecutive patients (85 women, median age 82.2 ± 5.5 years) by electrocardiogram (ECG)-triggered dual-source computed tomography angiography (CTA) after a median of 5 days post-transcatheter aortic valve implantation. The prosthesis was assessed for HALT. Apart from heparin, peri-interventional antithrombotic therapy consisted of single- (aspirin 29%) or dual- (aspirin plus clopidogrel 71%) antiplatelet therapy. Hypo-attenuated leaflet thickening was found in 16 patients [10.3% (95% confidence interval (CI) 5.5-15.0%)] of the patients. None of the baseline and procedural variables were significantly associated with HALT, nor did we find a significant association with the antithrombotic regimen, either peri-interventionally or at the time of CTA. Hypo-attenuated leaflet thickening was...
Chirurgische Gastroenterologie
ABSTRACT
RöFo - Fortschritte auf dem Gebiet der R
In this prospective study the diagnostic merit of radioimmunoscintigraphy (RIS) was compared with... more In this prospective study the diagnostic merit of radioimmunoscintigraphy (RIS) was compared with computed tomography (CT) and operation in the primary diagnostic procedure and follow-up of women with suspected ovarian cancer. In primary diagnosis, sensitivity, specificity, and diagnostic accuracy was 100%, 60% and 90% for RIS. In follow-up, sensitivity for local recurrence was slightly higher in CT than in RIS. It was possible to detect peritoneal carcinosis in the pelvis and lower abdominal region better with RIS, but in the upper abdominal region, peritoneal carcinosis was detected better with CT. If no differentiation between benign or malignant lesion, is possible with CT, differentiation will in many cases be possible with RIS.
Cardiology Clinics, 2012
Triage of patients with acute, potentially life-threatening chest pain is one of the most dauntin... more Triage of patients with acute, potentially life-threatening chest pain is one of the most daunting challenges currently facing emergency department physicians. Acute aortic syndrome and pulmonary embolism are two potentially underlying causes. For both, computed tomography has become the de facto clinical reference standard for diagnosis. This article discusses state-of-the-art computed tomography for the detection of these disorders, including recent advances and future perspectives.
RöFo - Fortschritte auf dem Gebiet der Röntgenstrahlen und der bildgebenden Verfahren, 1994
RöFo - Fortschritte auf dem Gebiet der Röntgenstrahlen und der bildgebenden Verfahren, 1990
RöFo - Fortschritte auf dem Gebiet der Röntgenstrahlen und der bildgebenden Verfahren, 2012
To retrospectively investigate the potential cause of contained rupture of the aortic root in bal... more To retrospectively investigate the potential cause of contained rupture of the aortic root in balloon-expandable transcatheter aortic valve implantation (TAVI) by means of pre- and postinterventional multislice computed tomography. Seventy-two patients (mean age 82±7 years, mean aortic valve area 0.69±0.19 cm(2)) underwent balloon-expandable TAVI using the EdwardsSAPIEN Transcatheter Heart Valve (23 mm, n=19; 26 mm, n=50; 29 mm, n=3). Aortic annulus dimensions were quantified by multislice computed tomography-based cross-sectional area assessment and average diameter calculation (CAAD) before and after TAVI. Post-TAVI multislice computed tomography data sets were available in 65 patients; contained aortic root rupture was diagnosed in 3 patients. Pre-TAVI CAAD was 23.1±1.8 mm; post-TAVI CAAD was 22.9±1.3 mm. Median relative change in CAAD pre- and post-TAVI was -0.5% (interquartile range, 3.6%). Relative increase of 5% to 10% was observed in 4 patients (1 with contained rupture), relative increase >10% in 2 patients, both with contained rupture. Mean relative oversizing, calculated as the relative difference in diameter between pre-TAVI CAAD and nominal diameter of the selected prosthesis, was 9.8%±7.8%. Relative oversizing was significantly higher in patients with contained rupture compared with patients without contained rupture (24.6%±5.4% versus 9.1%±6.6%; P<0.001). Relative oversizing ≥20% occurred in 6 patients (3 with contained rupture). Contained rupture of the aortic root in balloon-expandable TAVI is associated with severe prosthesis oversizing. Multislice computed tomography-based assessment of aortic annulus dimension in conjunction with adapted sizing guidelines may reduce the incidence of severe oversizing.
RöFo - Fortschritte auf dem Gebiet der Röntgenstrahlen und der bildgebenden Verfahren, 2011
CT angiography is the imaging modality of choice for the pre- and postsurgical evaluation of pati... more CT angiography is the imaging modality of choice for the pre- and postsurgical evaluation of patients with pathologies of the thoracic aorta. The purpose of this review is to familiarize the reader with the technical principle, recent technical developments and requirements for specific examination protocols and image interpretation, and to highlight common pathologies and findings.
Radiology, 1999
An unusual case of lipid embolization to brain and kidney after lymphography in a patient with no... more An unusual case of lipid embolization to brain and kidney after lymphography in a patient with non-Hodgkin lymphoma of the upper anterior mediastinum is reported. Contrast material-enhanced echocardiography demonstrated a right-to-left shunt to the left atrium without evidence of a patent foramen ovale. Echo contrast particles were transiently present within the tumor surrounding the great vessels.
Magnetic Resonance Materials in Physics, Biology and Medicine, 2006
To evaluate whether time-resolved 3D MR-angiography at 3T with a net acceleration factor of eight... more To evaluate whether time-resolved 3D MR-angiography at 3T with a net acceleration factor of eight is applicable in clinical routine and to evaluate whether good image quality and a low artifact level can be achieved with a temporal update rate that allows for additional information on pathologies. Thirty-one consecutive patients underwent time-resolved 3D contrast-enhanced MR-angiography on a 3T system. Imaging consisted of accelerated 3D gradient echo sequences combining parallel imaging with an acceleration factor of four, partial Fourier acquisition along phase and slice encoding direction, and twofold temporal acceleration using view sharing. Data volumes representing the arterial and venous contrast phases were independently evaluated by two experienced radiologists by grading of image quality and artifact level on a 0-3 scale. Time-resolved MR-angiography was successfully performed in all subjects without the need for contrast agent bolus timing. Excellent arterial (average score = 2.65 +/- 0.32) and good venous (average score = 2.56 +/- 0.28) diagnostic image quality and little image degrading due to artifacts (average score = 2.20 +/- 0.16) were confirmed by both independent readers (agreement in 65.2% of all evaluations). In 14 patients vascular pathologies were identified in the arterial phases. In eight examinations temporal resolution and depiction of contrast agent dynamics provided additional information about pathology. Without the necessity for additional bolus timing, time-resolved 3D contrast-enhanced MR-angiography with imaging acceleration along both the spatial encoding direction and temporal domain revealed excellent diagnostic image quality in neurovascular and thoracic imaging. Despite the limited spatial resolution as compared to high-resolution imaging of the carotid artery bifurcation, the results demonstrate the applicability of contrast-enhanced MR-angiography in thoracic and abdominal MRA as well as cervical imaging with a temporal update rate allowing for additional information on pathologies. Future studies may include an evaluation of optimal trade-offs between spatial and temporal resolution, different acceleration factors and a comparison to the gold-standard for accuracy.
Journal of Vascular Surgery, 2009
Journal of Magnetic Resonance Imaging, 2007
Journal of Magnetic Resonance Imaging, 2002
To prospectively evaluate hematopoietic bone marrow of male professional cyclists in relation to ... more To prospectively evaluate hematopoietic bone marrow of male professional cyclists in relation to performance data and laboratory data, and in comparison to age-matched healthy volunteers. Twenty male cyclists and 44 volunteers (27 males and 17 females) were prospectively studied by magnetic resonance imaging (MRI) at high-field strength. A sagittal T1-weighted (T1-w) spin-echo (SE) sequence, a gradient-echo (GE) sequence with an echo time (TE) for out-of-phase (OOP) imaging, and a turbo inversion-recovery sequence with short inversion time (TIRM) for fat suppression was used. The averaged bone marrow signal intensity (SI) of three adjacent vertebrae was related to the signal of an adjacent nondegenerative disk. The cyclists revealed a significantly different SI as compared to male volunteers in the OOP (0.34 +/- 0.14 vs. 0.28 +/- 0.09, P < 0.05) and T1-w sequences (1.62 +/- 0.19 vs. 1.77 +/- 0.30, P < 0.05). Only in TIRM was there a significant difference compared to female volunteers (0.36 +/- 0.08 vs. 0.44 +/- 0.04, P < 0.01). MRI data of cyclists did not correlate to hemoglobin, erythrocyte, or reticulocyte counts; ferritin, relative heart volume, relative maximal power (rPmax; W/kg bw), or relative maximal oxygen consumption (VO(2)max). A borderline linear correlation was found for hematocrit (OOP: r = 0.42, P = 0.06; TIRM: r = 0.44, P = 0.06). Bone marrow hyperplasia is observed in male professional cyclists in the axial skeleton. The MR findings are probably independent of mechanically induced marrow edema. A multifactorial cause must be considered, as single laboratory and performance data did not appear to contribute significantly to these results.
Journal of Endourology, 1995
In 50 patients treated for urolithiasis by extracorporeal shockwave lithotripsy (ESWL++), the rad... more In 50 patients treated for urolithiasis by extracorporeal shockwave lithotripsy (ESWL++), the radiographs taken before and 1 day afterward were initially assessed by conventional radiography and subsequently after standardized digitization and postprocessing. Clinical outcome and passage of stone fragments were reevaluated 3 weeks after ESWL. Using specially developed software routines, new disintegration parameters could be obtained by detecting the number of relevant minima in light-intensity distribution along the length axis of the concrement in digitized images. Comparing the digitized images before with those after ESWL, the concremental surface and axial length in digitized images on average showed no statistically significant difference. However, the number of visually and automatically detected light-intensity minima of the concrement region in digitized images obtained 1 day after ESWL was significantly higher than prior to ESWL and correlated significantly with the number of fissure lines in the conventional images. These new features in digitized images showed a high sensitivity in predicting later passage of stone fragments. Moreover, in six of the seven patients without detectable fissure lines in the early conventional radiographs but obvious signs of concretemental disintegration 3 weeks after ESWL, there was an increase in the number of light-intensity minima in the digitized images 1 day after ESWL. Our findings indicate that this method of digitization and post-processing of radiographs may improve the assessment of ESWL effectiveness by improving standardization in the analysis of all surveyed parameters and by offering new relevant disintegration measures.
Journal of Computer Assisted Tomography, 1989
Single photon emission computed tomography (SPECT) examinations of regional cerebral blood flow (... more Single photon emission computed tomography (SPECT) examinations of regional cerebral blood flow (rCBF) and regional cerebral blood volume (rCBV) were carried out in 23 patients with 19 subacute and 7 chronic cerebral infarctions. Corresponding magnetic resonance (MR) examinations (unenhanced and contrast enhanced scans) were done within a time interval of 2 days. Although all subacute lesions showed an increased rCBV, the rCBF could be either increased or decreased. Contrast enhancement in MR was associated with increased rCBV but not with increased rCBF. In all chronic lesions rCBV and rCBF were decreased and there was no contrast enhancement detectable in MR. The application of Gd-diethylenetriamine pentaacetic acid as contrast agent in MR demonstrates blood-brain barrier disruption as focal or gyral contrast enhancement in cerebral infarction. The SPECT examinations revealed an increased rCBV indicating a vasodilation or vasoparalysis. The rCBF was either increased or decreased depending on the collateral formation or recanalization of occluded vessels.
Journal of Cardiovascular Pharmacology, 1989
Thirty-two hypertensive subjects with diastolic blood pressure greater than 95 mm Hg were treated... more Thirty-two hypertensive subjects with diastolic blood pressure greater than 95 mm Hg were treated with ramipril over a period of 3 months. To determine the effective decrease of blood pressure and for reliable and reproducible demonstration of regression of myocardial hypertrophy during ramipril treatment, we performed parallel measurements with magnetic resonance imaging (MRI) and echocardiography. Measurements were carried out before treatment, 4 h after the first dose, and after 14 days and 3 months of treatment. MRI slices showed a significant decrease of interventricular septal thickness from 19.57 to 15.20 mm, whereas echocardiography demonstrated an equivalent decrease from 18.78 to 14.57 mm. At each measuring point, quantification of wall thickness was performed three times and the means were calculated. The septum and the posterior wall of the left ventricle were also measured at three different points. The values were obtained with negligible scatter and the changes with ramipril treatment were highly significant (p less than 0.001). A concomitant decrease of blood pressure was also observed. The therapeutic aim to reduce diastolic blood pressures below 90 mm Hg was achieved in all patients. In addition to the significant reduction in blood pressure, the angiotensin converting enzyme (ACE) inhibitor ramipril caused a significant regression of pathologic left ventricular hypertrophy demonstrated by magnetic resonance imaging and echocardiography.
JACC: Cardiovascular Interventions, 2012
This study sought to investigate pulsatile changes of the aortic annulus and their impact on pros... more This study sought to investigate pulsatile changes of the aortic annulus and their impact on prosthesis selection by computed tomography (CT). Precise noninvasive prosthesis sizing is a prerequisite for transcatheter aortic valve replacement. A total of 110 patients with severe aortic stenosis (mean age: 82.9 ± 8 years, mean aortic valve area: 0.69 ± 0.18 cm(2)) underwent electrocardiogram-gated CT. Aortic annulus dimensions were planimetrically quantified as area-derived diameter (D(A) = 2 ×✓(CSA/π), where CSA is the cross-sectional area) and perimeter-derived diameter (D(P) = P/π, where P is the length of the perimeter) in 5% increments of the RR interval. Hypothetical prosthesis sizing was based on D(A) and D(P) (23-mm prosthesis for <22 mm; 26 mm: 22 to 25 mm; 29 mm: >25 mm) and compared between maximum and traditional cardiac CT reconstruction phases at 35% and 75% of RR. Agreement for prosthesis selection was calculated by κ statistics. D(A) and D(P) were increased and eccentricity was reduced during systole, with D(A-MAX) and D(P-MAX) most often observed at 20% of RR. D(P) was consistently larger than D(A). Average net differences were 2.0 ± 0.6 mm and 1.7 ± 0.5 mm by D(A-MIN) versus D(A-MAX) and D(P-MIN) versus D(P-MAX). Agreement for prosthesis sizing was found in 93 of 110 patients (κ = 0.75) by D(A-75%) and in 80 of 110 patients (κ = 0.53) by D(A-MAX) compared with D(A-35%); and in 94 of 110 patients (κ = 0.73) by D(P-75%) and in 93 of 110 patients (κ = 0.73) by D(P-MAX) compared with D(P-35%). With sizing by D(A-75%) or D(P-75%), nominal prosthesis diameter was smaller than D(A-MAX) or D(P-MAX) in 15 and 6 patients respectively. Aortic annulus morphology exhibits conformational pulsatile changes throughout the cardiac cycle due to deformation and stretch. These changes affect prosthesis selection. Prosthesis selection by diastolic perimeter- or area-derived dimensions harbors the risk of undersizing.
RöFo - Fortschritte auf dem Gebiet der R
The capabilities of a patient-oriented digital optical laser-card for the documentation of the im... more The capabilities of a patient-oriented digital optical laser-card for the documentation of the image/report unit and for image transmission were assessed. 150 conventional X-rays covering the fields of urology (n = 50), traumatology (n = 50) and orthopaedics (n = 50) were digitised using a CCD scanner and subsequently transmitted to an Image-Transfer Medium (ITM) and to an optical laser-card. The image quality for the detection of relevant diagnostic parameters was evaluated by 4 radiologists and one clinician of the corresponding specialty. Based upon a total of 4740 decision readings for each method, it was found that the optical laser-card reduced the image quality significantly (p < 0.01) in comparison to the digitised ITM images in all fields. Thus, a primary diagnostic statement cannot be made based upon the images of the optical card. However, concomitant documentation of the image and opinion on the card may be used for the transmission of the radiological report, especially to external referring institutions.
European heart journal, Jan 7, 2015
We sought to evaluate the frequency of early hypo-attenuated leaflet thickening (HALT) of the SAP... more We sought to evaluate the frequency of early hypo-attenuated leaflet thickening (HALT) of the SAPIEN 3 transcatheter aortic valve (S3). Of 249 patients who had undergone S3 implantation, we studied 156 consecutive patients (85 women, median age 82.2 ± 5.5 years) by electrocardiogram (ECG)-triggered dual-source computed tomography angiography (CTA) after a median of 5 days post-transcatheter aortic valve implantation. The prosthesis was assessed for HALT. Apart from heparin, peri-interventional antithrombotic therapy consisted of single- (aspirin 29%) or dual- (aspirin plus clopidogrel 71%) antiplatelet therapy. Hypo-attenuated leaflet thickening was found in 16 patients [10.3% (95% confidence interval (CI) 5.5-15.0%)] of the patients. None of the baseline and procedural variables were significantly associated with HALT, nor did we find a significant association with the antithrombotic regimen, either peri-interventionally or at the time of CTA. Hypo-attenuated leaflet thickening was...
Chirurgische Gastroenterologie
ABSTRACT
RöFo - Fortschritte auf dem Gebiet der R
In this prospective study the diagnostic merit of radioimmunoscintigraphy (RIS) was compared with... more In this prospective study the diagnostic merit of radioimmunoscintigraphy (RIS) was compared with computed tomography (CT) and operation in the primary diagnostic procedure and follow-up of women with suspected ovarian cancer. In primary diagnosis, sensitivity, specificity, and diagnostic accuracy was 100%, 60% and 90% for RIS. In follow-up, sensitivity for local recurrence was slightly higher in CT than in RIS. It was possible to detect peritoneal carcinosis in the pelvis and lower abdominal region better with RIS, but in the upper abdominal region, peritoneal carcinosis was detected better with CT. If no differentiation between benign or malignant lesion, is possible with CT, differentiation will in many cases be possible with RIS.
Cardiology Clinics, 2012
Triage of patients with acute, potentially life-threatening chest pain is one of the most dauntin... more Triage of patients with acute, potentially life-threatening chest pain is one of the most daunting challenges currently facing emergency department physicians. Acute aortic syndrome and pulmonary embolism are two potentially underlying causes. For both, computed tomography has become the de facto clinical reference standard for diagnosis. This article discusses state-of-the-art computed tomography for the detection of these disorders, including recent advances and future perspectives.
RöFo - Fortschritte auf dem Gebiet der Röntgenstrahlen und der bildgebenden Verfahren, 1994
RöFo - Fortschritte auf dem Gebiet der Röntgenstrahlen und der bildgebenden Verfahren, 1990
RöFo - Fortschritte auf dem Gebiet der Röntgenstrahlen und der bildgebenden Verfahren, 2012
To retrospectively investigate the potential cause of contained rupture of the aortic root in bal... more To retrospectively investigate the potential cause of contained rupture of the aortic root in balloon-expandable transcatheter aortic valve implantation (TAVI) by means of pre- and postinterventional multislice computed tomography. Seventy-two patients (mean age 82±7 years, mean aortic valve area 0.69±0.19 cm(2)) underwent balloon-expandable TAVI using the EdwardsSAPIEN Transcatheter Heart Valve (23 mm, n=19; 26 mm, n=50; 29 mm, n=3). Aortic annulus dimensions were quantified by multislice computed tomography-based cross-sectional area assessment and average diameter calculation (CAAD) before and after TAVI. Post-TAVI multislice computed tomography data sets were available in 65 patients; contained aortic root rupture was diagnosed in 3 patients. Pre-TAVI CAAD was 23.1±1.8 mm; post-TAVI CAAD was 22.9±1.3 mm. Median relative change in CAAD pre- and post-TAVI was -0.5% (interquartile range, 3.6%). Relative increase of 5% to 10% was observed in 4 patients (1 with contained rupture), relative increase >10% in 2 patients, both with contained rupture. Mean relative oversizing, calculated as the relative difference in diameter between pre-TAVI CAAD and nominal diameter of the selected prosthesis, was 9.8%±7.8%. Relative oversizing was significantly higher in patients with contained rupture compared with patients without contained rupture (24.6%±5.4% versus 9.1%±6.6%; P<0.001). Relative oversizing ≥20% occurred in 6 patients (3 with contained rupture). Contained rupture of the aortic root in balloon-expandable TAVI is associated with severe prosthesis oversizing. Multislice computed tomography-based assessment of aortic annulus dimension in conjunction with adapted sizing guidelines may reduce the incidence of severe oversizing.
RöFo - Fortschritte auf dem Gebiet der Röntgenstrahlen und der bildgebenden Verfahren, 2011
CT angiography is the imaging modality of choice for the pre- and postsurgical evaluation of pati... more CT angiography is the imaging modality of choice for the pre- and postsurgical evaluation of patients with pathologies of the thoracic aorta. The purpose of this review is to familiarize the reader with the technical principle, recent technical developments and requirements for specific examination protocols and image interpretation, and to highlight common pathologies and findings.
Radiology, 1999
An unusual case of lipid embolization to brain and kidney after lymphography in a patient with no... more An unusual case of lipid embolization to brain and kidney after lymphography in a patient with non-Hodgkin lymphoma of the upper anterior mediastinum is reported. Contrast material-enhanced echocardiography demonstrated a right-to-left shunt to the left atrium without evidence of a patent foramen ovale. Echo contrast particles were transiently present within the tumor surrounding the great vessels.
Magnetic Resonance Materials in Physics, Biology and Medicine, 2006
To evaluate whether time-resolved 3D MR-angiography at 3T with a net acceleration factor of eight... more To evaluate whether time-resolved 3D MR-angiography at 3T with a net acceleration factor of eight is applicable in clinical routine and to evaluate whether good image quality and a low artifact level can be achieved with a temporal update rate that allows for additional information on pathologies. Thirty-one consecutive patients underwent time-resolved 3D contrast-enhanced MR-angiography on a 3T system. Imaging consisted of accelerated 3D gradient echo sequences combining parallel imaging with an acceleration factor of four, partial Fourier acquisition along phase and slice encoding direction, and twofold temporal acceleration using view sharing. Data volumes representing the arterial and venous contrast phases were independently evaluated by two experienced radiologists by grading of image quality and artifact level on a 0-3 scale. Time-resolved MR-angiography was successfully performed in all subjects without the need for contrast agent bolus timing. Excellent arterial (average score = 2.65 +/- 0.32) and good venous (average score = 2.56 +/- 0.28) diagnostic image quality and little image degrading due to artifacts (average score = 2.20 +/- 0.16) were confirmed by both independent readers (agreement in 65.2% of all evaluations). In 14 patients vascular pathologies were identified in the arterial phases. In eight examinations temporal resolution and depiction of contrast agent dynamics provided additional information about pathology. Without the necessity for additional bolus timing, time-resolved 3D contrast-enhanced MR-angiography with imaging acceleration along both the spatial encoding direction and temporal domain revealed excellent diagnostic image quality in neurovascular and thoracic imaging. Despite the limited spatial resolution as compared to high-resolution imaging of the carotid artery bifurcation, the results demonstrate the applicability of contrast-enhanced MR-angiography in thoracic and abdominal MRA as well as cervical imaging with a temporal update rate allowing for additional information on pathologies. Future studies may include an evaluation of optimal trade-offs between spatial and temporal resolution, different acceleration factors and a comparison to the gold-standard for accuracy.
Journal of Vascular Surgery, 2009
Journal of Magnetic Resonance Imaging, 2007
Journal of Magnetic Resonance Imaging, 2002
To prospectively evaluate hematopoietic bone marrow of male professional cyclists in relation to ... more To prospectively evaluate hematopoietic bone marrow of male professional cyclists in relation to performance data and laboratory data, and in comparison to age-matched healthy volunteers. Twenty male cyclists and 44 volunteers (27 males and 17 females) were prospectively studied by magnetic resonance imaging (MRI) at high-field strength. A sagittal T1-weighted (T1-w) spin-echo (SE) sequence, a gradient-echo (GE) sequence with an echo time (TE) for out-of-phase (OOP) imaging, and a turbo inversion-recovery sequence with short inversion time (TIRM) for fat suppression was used. The averaged bone marrow signal intensity (SI) of three adjacent vertebrae was related to the signal of an adjacent nondegenerative disk. The cyclists revealed a significantly different SI as compared to male volunteers in the OOP (0.34 +/- 0.14 vs. 0.28 +/- 0.09, P < 0.05) and T1-w sequences (1.62 +/- 0.19 vs. 1.77 +/- 0.30, P < 0.05). Only in TIRM was there a significant difference compared to female volunteers (0.36 +/- 0.08 vs. 0.44 +/- 0.04, P < 0.01). MRI data of cyclists did not correlate to hemoglobin, erythrocyte, or reticulocyte counts; ferritin, relative heart volume, relative maximal power (rPmax; W/kg bw), or relative maximal oxygen consumption (VO(2)max). A borderline linear correlation was found for hematocrit (OOP: r = 0.42, P = 0.06; TIRM: r = 0.44, P = 0.06). Bone marrow hyperplasia is observed in male professional cyclists in the axial skeleton. The MR findings are probably independent of mechanically induced marrow edema. A multifactorial cause must be considered, as single laboratory and performance data did not appear to contribute significantly to these results.
Journal of Endourology, 1995
In 50 patients treated for urolithiasis by extracorporeal shockwave lithotripsy (ESWL++), the rad... more In 50 patients treated for urolithiasis by extracorporeal shockwave lithotripsy (ESWL++), the radiographs taken before and 1 day afterward were initially assessed by conventional radiography and subsequently after standardized digitization and postprocessing. Clinical outcome and passage of stone fragments were reevaluated 3 weeks after ESWL. Using specially developed software routines, new disintegration parameters could be obtained by detecting the number of relevant minima in light-intensity distribution along the length axis of the concrement in digitized images. Comparing the digitized images before with those after ESWL, the concremental surface and axial length in digitized images on average showed no statistically significant difference. However, the number of visually and automatically detected light-intensity minima of the concrement region in digitized images obtained 1 day after ESWL was significantly higher than prior to ESWL and correlated significantly with the number of fissure lines in the conventional images. These new features in digitized images showed a high sensitivity in predicting later passage of stone fragments. Moreover, in six of the seven patients without detectable fissure lines in the early conventional radiographs but obvious signs of concretemental disintegration 3 weeks after ESWL, there was an increase in the number of light-intensity minima in the digitized images 1 day after ESWL. Our findings indicate that this method of digitization and post-processing of radiographs may improve the assessment of ESWL effectiveness by improving standardization in the analysis of all surveyed parameters and by offering new relevant disintegration measures.
Journal of Computer Assisted Tomography, 1989
Single photon emission computed tomography (SPECT) examinations of regional cerebral blood flow (... more Single photon emission computed tomography (SPECT) examinations of regional cerebral blood flow (rCBF) and regional cerebral blood volume (rCBV) were carried out in 23 patients with 19 subacute and 7 chronic cerebral infarctions. Corresponding magnetic resonance (MR) examinations (unenhanced and contrast enhanced scans) were done within a time interval of 2 days. Although all subacute lesions showed an increased rCBV, the rCBF could be either increased or decreased. Contrast enhancement in MR was associated with increased rCBV but not with increased rCBF. In all chronic lesions rCBV and rCBF were decreased and there was no contrast enhancement detectable in MR. The application of Gd-diethylenetriamine pentaacetic acid as contrast agent in MR demonstrates blood-brain barrier disruption as focal or gyral contrast enhancement in cerebral infarction. The SPECT examinations revealed an increased rCBV indicating a vasodilation or vasoparalysis. The rCBF was either increased or decreased depending on the collateral formation or recanalization of occluded vessels.
Journal of Cardiovascular Pharmacology, 1989
Thirty-two hypertensive subjects with diastolic blood pressure greater than 95 mm Hg were treated... more Thirty-two hypertensive subjects with diastolic blood pressure greater than 95 mm Hg were treated with ramipril over a period of 3 months. To determine the effective decrease of blood pressure and for reliable and reproducible demonstration of regression of myocardial hypertrophy during ramipril treatment, we performed parallel measurements with magnetic resonance imaging (MRI) and echocardiography. Measurements were carried out before treatment, 4 h after the first dose, and after 14 days and 3 months of treatment. MRI slices showed a significant decrease of interventricular septal thickness from 19.57 to 15.20 mm, whereas echocardiography demonstrated an equivalent decrease from 18.78 to 14.57 mm. At each measuring point, quantification of wall thickness was performed three times and the means were calculated. The septum and the posterior wall of the left ventricle were also measured at three different points. The values were obtained with negligible scatter and the changes with ramipril treatment were highly significant (p less than 0.001). A concomitant decrease of blood pressure was also observed. The therapeutic aim to reduce diastolic blood pressures below 90 mm Hg was achieved in all patients. In addition to the significant reduction in blood pressure, the angiotensin converting enzyme (ACE) inhibitor ramipril caused a significant regression of pathologic left ventricular hypertrophy demonstrated by magnetic resonance imaging and echocardiography.
JACC: Cardiovascular Interventions, 2012
This study sought to investigate pulsatile changes of the aortic annulus and their impact on pros... more This study sought to investigate pulsatile changes of the aortic annulus and their impact on prosthesis selection by computed tomography (CT). Precise noninvasive prosthesis sizing is a prerequisite for transcatheter aortic valve replacement. A total of 110 patients with severe aortic stenosis (mean age: 82.9 ± 8 years, mean aortic valve area: 0.69 ± 0.18 cm(2)) underwent electrocardiogram-gated CT. Aortic annulus dimensions were planimetrically quantified as area-derived diameter (D(A) = 2 ×✓(CSA/π), where CSA is the cross-sectional area) and perimeter-derived diameter (D(P) = P/π, where P is the length of the perimeter) in 5% increments of the RR interval. Hypothetical prosthesis sizing was based on D(A) and D(P) (23-mm prosthesis for <22 mm; 26 mm: 22 to 25 mm; 29 mm: >25 mm) and compared between maximum and traditional cardiac CT reconstruction phases at 35% and 75% of RR. Agreement for prosthesis selection was calculated by κ statistics. D(A) and D(P) were increased and eccentricity was reduced during systole, with D(A-MAX) and D(P-MAX) most often observed at 20% of RR. D(P) was consistently larger than D(A). Average net differences were 2.0 ± 0.6 mm and 1.7 ± 0.5 mm by D(A-MIN) versus D(A-MAX) and D(P-MIN) versus D(P-MAX). Agreement for prosthesis sizing was found in 93 of 110 patients (κ = 0.75) by D(A-75%) and in 80 of 110 patients (κ = 0.53) by D(A-MAX) compared with D(A-35%); and in 94 of 110 patients (κ = 0.73) by D(P-75%) and in 93 of 110 patients (κ = 0.73) by D(P-MAX) compared with D(P-35%). With sizing by D(A-75%) or D(P-75%), nominal prosthesis diameter was smaller than D(A-MAX) or D(P-MAX) in 15 and 6 patients respectively. Aortic annulus morphology exhibits conformational pulsatile changes throughout the cardiac cycle due to deformation and stretch. These changes affect prosthesis selection. Prosthesis selection by diastolic perimeter- or area-derived dimensions harbors the risk of undersizing.