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  • 1
    Electronic Resource
    Electronic Resource
    Evaluation of myelination and myelination disorders with turbo inversion recovery magnetic resonance imaging (1997)
    Springer
    European radiology 7 (1997), S. 1478-1484 
    Details
    ISSN: 1432-1084
    Keywords: Key words: MR imaging ; Turbo inversion recovery ; Brain ; Growth and development ; Myelin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. The aim of our work was to determine the efficacy of turbo inversion recovery spin echo (TIRSE) pulse sequences in differentiating patients with normal and abnormal myelination. Twenty neurological normal children (aged 5 months to 12 years) as well as 65 children presenting clinically with neurologic developmental deficits (aged 2 months to 10 years) were examined using TIRSE, T1-weighted SE, and T2-weighted turbo SE pulse sequences. Contrast-to-noise-ratio (CNR) between myelinated white and gray matter was compared for the different pulse sequences. In addition, two readers analyzed all images qualitatively by consensus. The CNR values were significantly higher on TIRSE images as compared with conventional images (p 〈 0.05). Forty-two neurologically abnormal patients displayed a normal myelination on all sequences, whereas 23 showed an abnormal myelination. The TIRSE sequence provided a sensitive and specific depiction of an abnormal myelination in all of these patients. The TIRSE sequence provided additional information to conventional pulse sequences in determining myelination disorders in children, especially in children older than 2 years.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003300050320
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  • 2
    Electronic Resource
    Electronic Resource
    Imaging of trabecular bone structure in osteoporosis (1999)
    Springer
    European radiology 9 (1999), S. 1781-1788 
    Details
    ISSN: 1432-1084
    Keywords: Key words: Osteoporosis ; Trabecular bone ; Bone structure ; Texture analysis ; Bone mineral density
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. Osteoporosis is a metabolic bone disorder that is characterized by reduced bone mass and a deterioration of bone structure which results in an increased fracture risk. Since the disease is preventable, diagnostic techniques are of major importance. Standard techniques determine bone mineral density, whereas some of the newer techniques focus on trabecular structure. This article reviews structure analysis techniques in the diagnosis of osteoporosis. Imaging techniques applied to the assessment of trabecular bone structure include conventional radiography, magnification radiography, high-resolution CT (HRCT) and high-resolution MR imaging (HRMRI). The best results were obtained using high-resolution tomographic techniques. The highest spatial resolutions in vivo were achieved using HRMRI. The most common texture analysis techniques that have been used are morphological parameters (analogous to bone histomorphometry). Fractal dimension, co-occurrence matrices, mathematical filter techniques and autocorrelation functions are more complex techniques. Most of the studies evaluating structure analysis show that texture parameters and bone mineral density both predict bone strength and osteoporotic fractures, and that combining both techniques yields the best results in the diagnosis of osteoporosis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003300050922
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  • 3
    Electronic Resource
    Electronic Resource
    Fracture healing: direct magnification versus conventional radiography (1994)
    Springer
    European radiology 4 (1994), S. 341-346 
    Details
    ISSN: 1432-1084
    Keywords: Fracture healing ; Magnification radiography ; Roentgen technique
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The aim of the study was to evaluate the potential of magnification radiography in diagnosing fracture healing and assessing its complications. Seventy-three patients with fractures or who had undergone osteotomy were radiographed with both conventional (non-magnified) and magnification (5-fold) techniques. Since 10 patients were radiographed twice and 1 three times, 83 radiographs using each technique were obtained. All radiographs were analysed and the findings correlated with the patients' follow-up studies. The microfocal X-ray unit used for magnification radiography had a focal spot size of 20–130 μm. As an imaging system, digital luminescence radiography was employed with magnification, while normal film-screen systems were used with conventional radiography. Manification radiography proved superior to conventional radiography in 47% of cases: endosteal and periosteal callus formations were sen earlier and better in 26 cases, and osseous union could be evaluated with greater certainty in 33 cases. In 49% of cases magnification radiography was equal and in 4% inferior to conventional radiography. Additionally an “inter-observer analysis” was carried out. Anatomical and pathological structures were classified into one of four grades. Results were significantly (P 〈 0.01) better using magnification radiography. We conclude that the magnification technique is a good method for monitoring fracture healing in its early stages.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00599068
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  • 4
    Electronic Resource
    Electronic Resource
    Unraveling the Role of Structure and Density in Determining Vertebral Bone Strength (1997)
    Springer
    Calcified tissue international 61 (1997), S. 474-479 
    Details
    ISSN: 1432-0827
    Keywords: Key words: Vertebral strength — Magnification radiographs — Texture — Quantitative computed tomography.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract. The strength of bone is determined not only by bone density but also by structure. Therefore, quantification of the structure in radiographs by texture parameters may result in a better prediction of fracture risk. Since in radiographs density and structure are strongly correlated, the predictive power of texture parameters should be corrected for the influence of BMD to determine the additional information conveyed by these parameters. In this study, we evaluated the predictive power of various texture parameters based on the Grey-Level Dependence Method and the Morphological Gradient Method. This study was performed on 67 vertebrae obtained from 20 male and 12 female human cadaver thoracolumbar spines. BMD and area of the vertebral body were determined from QCT images and texture parameters were derived from direct magnification (DIMA) radiographs. The fracture force, measured under conditions simulating the in vivo situation, was corrected with the area of the vertebra to yield the fracture stress (FS). Results of the study indicate that BMD correlates significantly with FS r= 0.82 (P 〈 0.001, n= 24) and r= 0.94 (P 〈 0.001, n= 43) for female and male vertebrae, respectively. Correlation coefficients of the investigated texture parameters were as high as 0.80 (P 〈 0.001) and 0.67 (P 〈 0.001) for the female and male vertebrae, respectively. Multiple regression analysis showed that in female vertebrae, the addition of one texture parameter to BMD results in a better prediction of strength. The multiple correlation coefficient was 0.87 (P 〈 0.001) in this case. In male vertebrae, BMD was the best predictor of fracture stress. These results suggest that texture parameters, as measured in magnification radiographs, can predict bone strength. Whereas in all cases BMD is the best single predictor of bone strength, for women texture parameters contain useful additional information.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002239900370
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  • 5
    Electronic Resource
    Electronic Resource
    Power Spectral Analysis of Vertebral Trabecular Bone Structure from Radiographs: Orientation Dependence and Correlation with Bone Mineral Density and Mechanical Properties (1998)
    Springer
    Calcified tissue international 63 (1998), S. 482-489 
    Details
    ISSN: 1432-0827
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract. Trabecular bone structure and bone density contribute to the strength of bone and are potentially important in the study of osteoporosis. Fourier transforms of the textural patterns in radiographs of trabecular bone have previously been used for the measurement of trabecular bone structure in subjects, however, the relationship between these measures and biomechanical properties of bone have not previously been established. In this study radiographs were acquired of 28 cubic specimens of spinal trabecular bone along each of the three anatomic axes: cranio-caudal or superior-inferior (SI), medial-lateral (ML), and anterior-posterior (AP). The radiographs were digitized, background corrected, and uniformly aligned. The Fast Fourier transform (FFT) was performed on a region comprised solely of trabecular bone for each image. The zero (DC), first (FMO), and second moments (SMO) of the Fourier power spectrum and the fractal dimension (FD) as determined from the Fourier power spectrum were correlated with stereology measures, with bone mineral density (BMD) as well as with measured biomechanical properties [Young's elastic modulus (YM) and ultimate strength] of the cubes. The results show that the power spectra-based measures, when compared with structural parameters determined using 3D stereology, show good correlations with bone volume fraction, trabecular spacing, thickness, and number. These power spectral measures showed fair to good correlations with BMD and the biomechanical properties. Moreover, the correlations between the power spectral measures of trabecular structure and the BMD, YM, and stereology measures of structure depend on the orientation of the radiographic image. Specifically, these were significant differences in the measured biomechanical properties and the power spectral measures of the trabecular structure between the SI and ML and the SI and AP directions. In addition, depending on the spatial frequency range for analysis, the fractal dimension showed opposite trends with changes in BMD and biomechanical properties. Multivariate regression models showed the correlation coefficients increasing with the inclusion of some of the power spectral measures, suggesting that FFT-based texture analysis may play a potential role in studies of osteoporosis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002239900562
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  • 6
    Electronic Resource
    Electronic Resource
    Cross-sectional Area of Lumbar Vertebrae in Peri- and Postmenopausal Patients With and Without Osteoporosis (2000)
    Springer
    Osteoporosis international 11 (2000), S. 304-309 
    Details
    ISSN: 1433-2965
    Keywords: Key words:Lumbar vertebrae, area – Osteoporosis – Quantitative computed tomography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract: The purpose of this study was to analyze the midvertebral area of lumbar vertebrae in osteoporotic and nonosteoporotic female patients and to find out whether the midvertebral area may be used as an additional parameter in the diagnosis of osteoporosis. In 195 peri- and postmenopausal patients (average age 51.7 ± 5.2 years) trabecular and cortical bone mineral density (BMD) were determined using quantitative CT (QCT) in L2–4. In addition, midvertebral cross-sectional area was measured in a standardized fashion on the CT sections and the height of the second lumbar vertebra was determined on the lateral digital radiographs. Body height and weight were obtained and vertebral fracture status was determined. According to WHO criteria 29 patients (average age 57.2 years) were considered osteoporotic, 93 osteopenic (average age 52.2 years) and 73 normal (average age 48.6 years). Body weight and size did not show significant differences between the individual groups. Average midvertebral area was 1278 ± 173 mm2 in the osteoporotic patients, 1186 ± 125 mm2 in the osteopenic patients and 1126 ± 127 mm2 in the normals. A correlation of r=−0.39 (p〈0.05) was obtained between BMD and area. Thirty-six of 195 patients showed osteoporotic vertebral fractures. Midvertebral area in these patients was 1266 ± 171 mm2 versus 1159 ± 133 mm2 in the nonfractured females (p〈0.05). We therefore conclude that the lumbar midvertebral area is larger in osteoporotic and osteopenic patients compared with women with normal BMD. In contrast to biomechanical considerations midvertebral area seems not to be suited as an additional measure of bone strength in vivo.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001980070118
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  • 7
    Electronic Resource
    Electronic Resource
    Trabecular Bone Architecture in the Distal Radius Using Magnetic Resonance Imaging in Subjects with Fractures of the Proximal Femur (1999)
    Springer
    Osteoporosis international 10 (1999), S. 231-239 
    Details
    ISSN: 1433-2965
    Keywords: Key words:Calcaneus – High-resolution MRI – Osteoporosis – Radius – Structural analysis – Trabecular bone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract: To determine whether magnetic resonance (MR)-derived measures of trabecular bone architecture in the distal radius are predictive for prevalent hip fractures, 20 subjects with hip fractures and 19 age-matched postmenopausal controls were studied. Bone mineral density (BMD) measures at the hip (dual-energy X-ray absorptiometry, DXA) and the distal radius (peripheral quantitative computed tomography, pQCT) were also obtained. We compared the MR-based structural measures derived in the radius with those in the calcaneus of the same patients. In the radius, images were acquired at an in-plane resolution of 156 μm and a slice thickness of 0.5 mm. Stereologic measures such as the apparent trabecular thickness (app. Tb.Th), fractional trabecular bone volume (app. BV/TV), trabecular spacing (app. Tb.Sp) and trabecular number (app. Tb.N) were derived from the images. Measures of app. Tb.Sp and app. Tb.N in the distal radius showed significant (p〈0.05) differences between the two groups, as did hip BMD measures. However, radial trabecular BMD measures showed only a marginal difference (p= 0.05). Receiver operating curve analysis was used to determine the diagnostic efficacy of BMD, structural measures and a combination of the two. The area under the curve (AUC) for total hip BMD was 0.73, and for radial trabecular BMD was 0.69. AUC for most of the measures of trabecular bone structure at the distal radius was lower than for hip BMD measures; however, AUC for app. Tb.N at the radius was 0.69, comparable to trabecular BMD using pQCT. The AUC for combined BMD (hip) and structure measures was higher (0.87) when radius and calcaneus structure was included. Measures of trabecular architecture derived from MR images combined with BMD measures improve the discrimination between subjects with hip fractures and normal age-matched controls.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001980050221
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  • 8
    Electronic Resource
    Electronic Resource
    Computergestützte Strukturanalyse des trabekulären Knochens in der Osteoporosediagnostik (1998)
    Springer
    Der Radiologe 38 (1998), S. 853-859 
    Details
    ISSN: 1432-2102
    Keywords: Schlüsselwörter Osteoporose ; Trabekulärer Knochen ; Knochenstruktur ; Texturanalyse ; Knochenmineraldichte ; Key words Osteoporosis ; Trabecular bone ; Bone structure ; Texture analysis ; Bone mineral density
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary Osteoporosis is characterized by reduced bone mass and a deterioration of bone structure which results in an increased fracture risk. The purpose of this review is to evaluate structure analysis techniques in the diagnosis of osteoporosis. Several imaging techniques were applied to analyze trabecular bone, such as conventional radiography, high-resolution computed tomography (HR-CT) and high-resolution magnetic resonance imaging (HR-MRI). The best results were obtained using high-resolution tomographic techniques. The highest spatial resolutions in vivo were achieved using HR-MRI. These studies show that texture parameters and bone mineral density predict bone strength and osteoporotic fractures in a complementary fashion. Combining both techniques yields the best results in the diagnosis of osteoporosis.
    Notes: Zusammenfassung Bei der Osteoporose kommt es zu einem Knochenmassenverlust und zu einem Umbau der trabekulären Knochenstruktur mit erhöhter Frakturgefährdung. Ziel der vorliegenden Übersicht ist es, den Stellenwert strukturanalytischer Verfahren im Rahmen der Osteoporosediagnostik zu analysieren. Als bildgebende Verfahren zur Strukturanalyse wurden konventionelle Radiographie, hochauflösende Computertomographie (HR-CT) und hochauflösende Magnetresonanztomographie (HR-MRT) eingesetzt. Die besten Ergebnisse wurden mit hochauflösenden tomographischen Verfahren erzielt, wobei die hochauflösende MRT die beste Ortsauflösung erzielte. Die vorliegenden Untersuchungen zeigen, daß Texturparameter und Knochendichte sich komplementär zueinander verhalten. Die Kombination beider Verfahren erzielt die beste Prädiktion der biomechanisch bestimmten Knochenstabilität und die beste Differenzierung von Patienten mit und ohne osteoporotische Frakturen.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001170050434
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  • 9
    Electronic Resource
    Electronic Resource
    Imaging of bone tumors: evaluation of direct magnification radiography (1996)
    Springer
    Skeletal radiology 25 (1996), S. 441-447 
    Details
    ISSN: 1432-2161
    Keywords: Key words Bone neoplasms ; diagnosis ; Magnification radiography ; Bones ; radiography ; Radiography ; comparative studies ; Radiography ; technology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Objective. To evaluate the potentials of magnification radiography as compared with conventional radiography in diagnosing bone tumors. Design and patients. Sixty-two patients with primary bone tumors and tumorlike lesions underwent radiography with both conventional (non-magnified) and magnification (fivefold) techniques. All radiographs were analyzed by four radiologists and the findings correlated with the histopathology findings. The microfocal X-ray unit used for magnification radiography had a focal spot size of 20–130 μm. Digital luminescence radiography was employed with magnification, while normal film-screen systems were used with conventional radiography. Results. The diagnosis of benign and malignant lesions as well as the individual tumor diagnosis were determined with higher accuracy using magnification compared with conventional radiography (88% vs 75% and 71% vs 52%, p〈0.01). Margins of destruction, periosteal reactions and matrix patterns were evaluated with higher certainty by all of the radiologists (p〈0.01). Conclusion. Magnification radiography may improve the evaluation and diagnosis of bone tumors.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002560050112
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  • 10
    Electronic Resource
    Electronic Resource
    Einsatz von Gadoteridol in der MR-Diagnostik rheumatoider Gelenkveränderungen (1996)
    Springer
    Der Radiologe 36 (1996), S. 141-147 
    Details
    ISSN: 1432-2102
    Keywords: Schlüsselwörter Magnetresonanztomographie ; MR-Kontrastmittel ; paramagnetische ; Arthritiden ; Frühdiagnostik ; Chronische Polyarthritis ; Key words Magnetic resonance imaging ; MR contrast media ; paramagnetic ; Inflammatory joint disease ; diagnosis ; Rheumatoid arthritis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary Purpose: To investigate the diagnostic and clinical usefulness of a new non-ionic, hydrophilic gadolinium (III) chelate [Gd(HP-DO3A), gadoteridol, ProHance] and to compare it with Gd-DTPA (gadopentetate dimeglumine, Magnevist). Methods: In a Phase III clinical trial, 20 patients with rheumatic joint disease were examined before and after intravenous administration of gadoteridol in two different doses (0.1 and 0.3 mmol/kg bodyweight). Magnetic resonance imaging (MRI) was performed at 1.5 T with T1-weighted FLASH and T2-weighted spin echo sequences. Fourteen patients were examined with gadopentetate dimeglumine for comparison. Dynamic changes of signal intensity in the joints and muscle tissue were determined quantitatively. Results: No significant changes in cardiovascular data and no adverse effects occurred after injection of gadoteridol. The 0.3 mmol/kg dose showed no advantage in diagnostic contrast over the 0.1 mmol/kg dose. No significant differences (p 〉 0.01) were noted between gadoteridol and gadopentetate dimeglumine in patients with early rheumatoid arthritis. Conclusion: Gadoteridol proved useful in the detection of early rheumatoid arthritis. No significant differences were observed between the two gadoteridol doses. There were no diagnostically relevant differences between gadoteridol and gadopentetate dimeglumine.
    Notes: Zusammenfassung Ziel der Studie war es, die klinische Verträglichkeit und die diagnostische Wertigkeit von Gadoteridol für die Beurteilung entzündlicher Gelenkveränderungen zu untersuchen. Im Rahmen einer Phase-III-Studie wurden 20 Patienten mit rheumatischen Gelenkerkrankungen vor und nach intravenöser Injektion des gadoliniumhaltigen, paramagnetischen Kontrastmittels Gadoteridol (Gd(HP-DO3A), ProHance®) MR-tomographisch untersucht. Zwei Kontrastmitteldosen (0,1 und 0,3 mmol/kg Körpergewicht) wurden evaluiert und ein Vergleichskollektiv von 14 Patienten mit Gadopentetat Dimeglumin (Gd-DTPA, Magnevist®) untersucht. Dynamische Signalintensitätsveränderungen der Gelenkstrukturen nach Kontrastmittelinjektion wurden quantitativ bestimmt. Bei guter Verträglichkeit der Kontrastmittelverabreichung ergaben sich bis 2 h nach Injektion von Gadoteridol keine signifikanten Änderungen der Kreislaufparameter. Die Dosis von 0,1 mmol/kg Körpergewicht erwies sich bei 1,5 Tesla als diagnostisch ausreichend. Gadoteridol zeigte im Vergleich zu Gadopentetat Dimeglumin bei frühen rheumatischen Gelenkveränderungen keine signifikanten Unterschiede bezogen auf qualitative Parameter und quantitativ bestimmte dynamische Signalintensitätsveränderungen (p 〉 0,01).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001170050051
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