[Molecular imaging--a new emphasis in radiology].
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Diagnostic Imaging↗
Biomedical subjects
H Imhof
Publications and source records attributed to H Imhof.
[Interstitial pneumonias].
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Diagnosis, Differential↗
[Introduction to the topic: diagnosis of osteoporosis - a paradigm shift].
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Fractures, Spontaneous↗
[Status and integration of radiology in a large clinical center].
Radiology has undergone enormous technological and hence organizational changes in the last few decades. These changes occurred more or less in unison with total state expenditures for healthcare, whereas individual disposable income increased twice as much in the same timeframe (1988-2003). Costs for medical technology account for approximately 3-5% of national healthcare expenditures. On the national level, but also in a central hospital setting, radiology does not constitute a major cost factor. Tomographic investigations have increased by 2-3% in recent years and currently represent 30% of all radiological procedures. Increasing sophistication of diagnostics and treatment using genetic and molecular techniques, novel information technologies, and a critical evidence-based approach to all functional activity will result in a further explosion of knowledge. Radiology must meet these challenges head on by intensifying all forms of training, from basics to continuing professional education.
Delivery of Health Care, Integrated↗
[The role of projectional radiography in the detection of primary malignant and indeterminate bone neoplasms].
PURPOSE: To evaluate the role of projectional radiography in the detection of primary and potentially malignant bone neoplasms. MATERIALS AND METHODS: We retrospectively reviewed the images and medical records of 80 patients (42 male, 38 female; range: 6 to 73 years; mean: 33 years) with pathologically proven primary or indeterminate bone tumors. RESULTS: The most common symptom was local pain (84 %). In 69 of 80 patients (86 %), projectional radiography was the first imaging modality, which correctly identified the malignant character of the bone lesion in 60 of these 69 patients (87 %). In 2 patients, bone neoplasms were overlooked due to diagnostically inadequte image quality. The false-diagnosis rate was not significantly different between board-certified radiologists working in hospitals and radiologists in outpatient facilities (p > 0.05). Bone tumors predominantly affecting adults, such as chondrosarcomas, needed a longer time for the diagnosis than bone tumors mainly found in childhood, such as osteosarcomas. The median age of patients with delayed imaging work-up because of attempted conservative therapy (45 years +/- 20 years) was significant higher than the median age of patients with immediate radiographic work-up (27 years +/- 16 years). CONCLUSION: Projectional radiography is the most common initial imaging method for bone pain and continues to play an important role to reduce the time gap between first onset of symptoms and definitive treatment. In unremitting focal bone pain, bone neoplasms should be taken into consideration not only in children but also in patients beyond adolescence.
Adult↗
Quantification of axial alignment of the lower extremity on conventional and digital total leg radiographs.
The purpose was to assess axial alignment of the lower limb using mechanical axis measurements on conventional and digital radiographs. Total-leg radiographs of 24 patients, 8 male and 16 female, with a mean age of 68.6+/-10.2 years, were performed in a standardized anterior-posterior projection and standing position using a conventional and digital phosphor storage film screen radiography system. Knee joint angulation was assessed by measuring the angle between a line drawn from the center of the femoral head to the middle of the femoral condyles and a line drawn from the middle of the tibial condyles to the midpoint of the malleolus. On conventional leg radiographs, line drawing and angle measurement were performed manually with a transparent goniometer. Angle measurement on digital leg radiographs was performed on a PACS workstation using computer-assisted measurement software (IMPAX, AGFA-GEVAERT, Belgium). Evaluation time for both measurements was recorded. We diagnosed 14 varus and 10 valgus angulations of the knee joint. The mean individual difference between axis deviation of conventional digital leg radiographs was 0.93+0.6 degrees (min 0 degrees, max 2 degrees), the mean difference in varus angulation was 1.13+/-0.45 degrees (min 0.3 degrees, max 2 degrees), and the mean difference in valgus angulation was 0.65+/-0.71 degrees (min 0 degrees, max 2 degrees). Angle measurements on conventional and digital radiographs did not show any statistically significant difference. Mean time exposure was 4.9 min/patient for manual and 1.08 min/patient for computer-assisted angle measurement (P<0.001). Computer-assisted angle measurement on digital total-leg radiographs represents a reliable method with no significant angle differences compared to conventional radiographic systems and offers a significantly lower evaluation time.
Aged↗
[Shoulder instability].
Shoulder instability is a common clinical feature leading to recurrent pain and limited range of motion within the glenohumeral joint. Instability can be due a single traumatic event, general joint laxity or repeated episodes of microtrauma. Differentiation between traumatic and atraumatic forms of shoulder instability requires careful history and a systemic clinical examination. Shoulder laxity has to be differentiated from true instability followed by the clinical assessment of direction and degree of glenohumeral translation. Conventional radiography and CT are used for the diagnosis of bony lesions. MR imaging and MR arthrography help in the detection of soft tissue affection, especially of the glenoid labrum and the capsuloligamentous complex. The most common lesion involving the labrum is the anterior labral tear, associated with capsuloperiostal stripping (Bankart lesion). A number of variants of the Bankart lesion have been described, such as ALPSA, SLAP or HAGL lesions. The purpose of this review is to highlight different forms of shoulder instability and its associated radiological findings with a focus on MR imaging.
Arthrography↗
Tumors and tumor-like lesions of the neck: from childhood to adult.
In childhood, tumors and tumor-like lesions of the neck are rare and tend to be benign. Very common are congenital cystic lesions (thyroglossal duct cysts, branchial cysts, dermoid cysts, lymphangiomas, cystic hygromas). Common neoplastic lesions are hemangiomas and papillomas. The most common malignant tumors in the head and neck region are lymphomas and rhabdomyosarcomas. Lymph node enlargements, reactive or/and infectious, account also for a significant amount of cervical masses.
Adolescent↗
Radiological progression of joint damage in a longitudinal cohort of early DMARD-treated rheumatoid arthritis patients followed for 10 years.
OBJECTIVE: The efficacy of DMARD therapy in rheumatoid arthritis (RA) can be judged by radiological analysis. This study aimed to determine the time-dependent progression of joint damage, acute-phase response, and rates of radiologic progression in early DMARD-treated RA patients over 10 years. PATIENTS AND METHODS: We evaluated outpatient records, and radiographs of hands and feet of 54 early RA patients on DMARDs for 10 years. Radiographs were quantified by the Larsen method using recently developed quantification software. RESULTS: Radiological damage attenuated, with disease progression from baseline to Year 10 [correlation coefficient (r)=0.95, probability (p)<0.001]. Radiographic scores progressed more rapidly during the first 5 years than thereafter. Cumulative erythrocyte sedimentation rate (ESR) was strongly correlated with radiological progression (p<0.001, r=0.88). CONCLUSION: Our findings reveal a higher amount of radiographic RA progression during the first years of DMARD treatment. Thus, our data provide strong evidence for the importance of both early DMARD therapy and continuous radiographic assessments in RA.
Adult↗
Quantitation of transverse maxillary dimensions using computed tomography: a methodological and reproducibility study.
The present investigation was a methodological study of a new method of quantification of a series of factors in the transverse dimension of the maxilla including the nose, maxillary bones and dental arches, based on computer tomographic (CT) scanning. The aim was to investigate a series of parameters thought to be relevant in the differential diagnosis of discrepancies in the morphology of this area and probably affected by orthodontic appliances. Based on a standardized CT scanning registration of 10 subjects, a series of points on the scans were identified and then measured in a special cephalometric computer system (linear and angular values). The quantitation was repeated by each observer and inter- and intra-observer differences were calculated. The results demonstrated that virtually all the parameters showed a high degree of reproducibility at both levels and confirmed the statistical suitability of the method described. The method will be used in a series of ongoing studies regarding the morphology and treatment of discrepancies of the midface and therefore supplement the relatively sparse information based on quantitative reports concerning this important anatomical area.
Adult↗
[Computed tomography and magnetic resonance tomography of the normal temporal bone].
The normal anatomy of the temporal bone and the inner ear will be described in detail on high resolution computed tomography (HRCT) and magnetic resonance images. The imaging technique of computer tomography--either single detector or multi detector CT--is normally obtained in an axial plane without the intravenous application of contrast material. The images are reconstructed in a high resolution bone window level setting. The coronal images are reconstructed either if used single detector or multi detector CT. Only in some cases a scan in the coronal plane is directly obtained using a single detector CT. MR imaging of temporal bone is usually performed in a head coil. Axial high resolution 3D-T2-weighted sequences either in fast spin echo technique or gradient echo technique--for example CISS-sequence--are obtained, then an axial high resolution T1-weighted sequence before and after the application of gadopentate dimiglumine is performed. HRCT excellently demonstrates the osseous structures of the temporal bone as well as of the inner ear, while MRI excellently depicts soft tissue structures especially those of the inner ear. Due to the susceptibility artifacts MRI is not very suitable for imaging the external auditory canal or the middle ear or the pneumatic system. In conclusion HRCT is so far excellent to delineate the osseous structures of the temporal bone and inner ear while MRI excellently depicts the soft tissue structures of the inner ear, the internal auditory canal and the cerebellopontine angle. Reissner's membrane, the cochlear duct, and the organ of Corti cannot be visualized even using high-resolution MRI. HRCT and MRI are therefore used as complementary methods for imaging the temporal bone.
Anatomy, Cross-Sectional↗
[CT and MRI characteristics of tumours of the temporal bone and the cerebello-pontine angle].
Tumours lesions of the temporal bone and of the cerebello-pontine angle are rare. This tumours can be separated into benign and malignant lesions. In this paper the CT and MRI characteristics of tumours of the temporal bone and the cerebello-pontane angle will be demonstrated. High resolution CT (HRCT) as usually performed in the axial plane are using a high resolution bone window level setting, coronal planes are the reconstructed from the axial data set or will be obtained directly. With the MRI FLAIR sequence in the axial plane the whole brain will be scanned either to depict or exclude a tumour invasion into the brain. After this,T2-weighted fast spin echo sequences or fat suppressed inversion recovery sequences in high resolution technique in the axial plane will be obtained from the temporal bone and axial T1-weighted spin echo sequences before and after the intravenous application of contrast material will be obtained of this region. Finally T1-weighted spin echo sequences in high resolution technique with fat suppression after the intravenous application of contrast material will be performed in the coronal plane. HRCT and MRI are both used to depict the most exact tumorous borders. HRCT excellently depicts the osseous changes for example exostosis of the external auditory canal, while also with HRCT osseous changes maybe characterized into more benign or malignant types. MRI has a very high soft tissue contrast and may therefore either characterize vascular space-occupying lesions for example glomus jugulare tumours or may differentiate between more benign or malignant lesions. In conclusion HRCT and MRI of the temporal bone are excellent methods to depict and mostly characterize tumour lesions and can help to differentiate between benign and malignant lesion. These imaging methods shall be used complementary and may have a great impact for the therapeutic planning.
Adenocarcinoma↗
[Computed tomography and magnetic resonance imaging of congenital abnormalities of the temporal bone].
Congenital abnormalities of the temporal bone are mostly accompanied by conductive or sensori-neural hearing loss. Before any therapeutic procedures are done high resolution CT (HRCT) and magnetic resonance imaging (MRI) should be performed to establish the correct diagnosis and to plan the potentially surgical intervention. HRCT best depicts osseous changes especially those of the external auditory canal and the middle ear containing the ossicles and the osseous structures of the temporal bone and the petrous bone containing the inner ear. MRI excellently shows soft tissue changes of the inner ear especially on the high resolution 3DT2-weighted sequences which give a superb contrast between the nerves and the cerebro-spinal fluid. Malformations of the external auditory canal consists of aplasia or hypoplasia and those of the middle ear range form extreme hypoplasia or aplasia to very mild deformations of the ossicles. Malformations of the inner ear also range form complete aplasia to very mild hypoplasia of the organs of the inner ear as well as malformations concerning the nerves in the internal auditory canal range from aplasia to hypoplasia. Malformations of the temporal bone can either occur isolated or in combination in which malformations of the external and middle ear may be accompanied by those of the inner ear. Furthermore, malformations of the temporal bone may also occur in otofacial, otocervical or otoskeletal syndromes. These syndromes may be accompanied by certain malformations of the temporal bone. HRCT and MRI are both excellent methods to depict congenital abnormalities of the temporal bone and of the inner ear and should be used as complementary methods because HRCT best depicts osseous changes and MRI superbly depicts soft tissue changes. Both methods are important to establish the correct diagnosis to plan the therapeutic procedures.
Ear Canal↗
[Computed tomography and magnetic resonance imaging of acquired abnormalities of the inner ear and cerebello-pontine angle].
CT and MRI of acquired abnormalities of the inner ear and cerebello-pontine angle present themselves with very typical findings. The imaging should be adapted to the pathology looked for and either CT or MRI should be used alone or in combination. CT, especially high resolution CT (HRCT), provides an excellent bone contrast, while MRI has a much superior soft tissue contrast. Acute inflammatory changes of the inner ear are solely depicted by contrast-enhanced MRI. HRCT excellently depicts osseous changes of the inner ear and cerebellopontine angle such as chronic ossifying labyrinthitis occurring after acute labyrinthitis, otosclerotic or traumatic changes. Tumorous changes not yielding to bony changes are best delineated by MRI. Posttraumatic hemorrhage and chronic fibrotic changes within the labyrinth are depicted by MRI, only. In conclusion HRCT and MRI are excellent methods to delineate acquired abnormalities of the inner ear and cerebello-pontine angle. HRCT best depicts osseous changes while MRI best depicts soft tissue changes. HRCT and MRI are not concurrent methods but should better be used as complementary methods for imaging acquired abnormalities of inner ear and cerebellopontine angle.
Cerebellar Neoplasms↗
[Flat-screen detector systems in skeletal radiology].
Implementation of flat-panel detectors and digital integration of the technique instead of the use of conventional radiographs leads to a shortening of the work process. With flat-panel technology the image production process is shortened by more than 30%. Major advantages in the implementation of integrated RIS, PACS and flat-panel detector system are increases in quality because most mistakes in picture labeling can be avoided, easier handling without the need for cassettes, and the possibility of image post-processing. The diagnostic quality of the images in the field of musculoskeletal radiology is, in comparison to conventional radiographs, at least adequate and in most cases markedly improved with a marked reduction in radiation exposure of around 30-50%. With respect to the numerous advantages of the digital techniques and especially flat-panel technology there is a very high likelihood that conventional radiographs will be substituted in the coming years, even though the cost of the new technology is currently significantly higher compared to conventional systems.
Artifacts↗
Spiral CT and radiation dose.
Recent studies in the USA and Europe state that computed tomography (CT) scans compromise only 3-5% of all radiological exams, but they contribute 35-45% of total radiation dose to the patient population. These studies lead to concern by several public authorities. Basis of CT-dose measurements is the computed tomography dose index (CTDI), which was established 1981. Nowadays there are several modifications of the CTDI values, which may lead to confusion. It is suggested to use the standardized CTDI-100 w. value together with the dose length product in all CT-examinations. These values should be printed on all CT-images and allows an evaluation of the individualized patient dose. Nowadays, radiologist's aim must be to work at the lowest maximal diagnostic acceptable signal to noise ratio. To decrease radiation dose radiologist should use low kV and mA, but high pitches. Newly developed CT-dose-reduction soft-wares and filters should be installed in all CT-machines. We should critically compare the average dose used for a specific examination with the reference dose used in this country and/or Europe. Greater differences should caution the radiologist. Finally, we as radiologists must check very carefully all indications and recommend alternative imaging methods. But we have also to teach our customers-patients and medical doctors who are non-radiologists-that a 'good' image is not that which show all possible information, but that which visualize 'only' the diagnostic necessary information.
Europe↗
Head and neck imaging with MDCT.
Multi-slice CT (MDCT) is rapidly becoming the new standard in radiological imaging. Although its advantages in cardiovascular, thoracic and abdominal imaging are evident, the extent of its usefulness for imaging the head and neck has yet to be clarified. Because of the shorter examination time motion artifacts are reduced, phonation-studies are possible. Due to the thin-slicing and nearly isotropic multiplanar reconstruction (MPR) examination in only one plane is necessary, saving both time and radiation exposure. The shorter examination requires the use of higher concentrated contrast medium (400 mg of iodine/ml). The use of such a contrast medium produces a higher degree of contrast enhancement and provides a 5-10% higher contrast between the surrounding normal and pathological tissue, but is more time critical. MPRs are easily done in any plane within seconds and enables also three-dimensional visualization, what helps in the use of minimal invasive therapy, training and teaching and provides a way of handling the hundreds of images acquired during scanning.
Carcinoma, Squamous Cell↗
Comparison of imaging-guided and non-imaging-guided quantitative sonography of the calcaneus with dual X-ray absorptiometry of the spine and femur.
OBJECTIVE: The purpose of our study was to evaluate the diagnostic agreement between imaging-guided and non-imaging-guided quantitative sonography of the calcaneus and dual X-ray absorptiometry of the spine and femur to show osteoporosis. SUBJECTS AND METHODS: In 113 patients (73 women, 59 +/- 14 years old; 40 men, 48 +/- 16 years old), dual X-ray absorptiometry of the lumbar spine and the proximal femur, imaging-guided quantitative sonography, and non-imaging-guided quantitative sonography of the calcaneus were performed. The percentage of patients having a T-score equal to or less than a threshold of -2.5 SDs (prevalence of osteoporosis) was calculated for each imaging technique. The diagnostic agreement of the three techniques in identifying individuals with osteoporosis was assessed. RESULTS: Eleven percent of the women and 8% of the men were classified as osteoporotic by imaging-guided quantitative sonography, and 38% of the women and 25% of the men were so classified by non-imaging-guided quantitative sonography. At dual X-ray absorptiometry of the spine, 44% of the women and 38% of the men were classified as osteoporotic, and, at different femoral regions, 19-60% of the women and 8-38% of the men were so classified. Kappa analysis for both quantitative sonography techniques was not significant. Kappa analysis for both quantitative sonography techniques and dual X-ray absorptiometry showed diagnostic agreement to be generally poor. CONCLUSION: No advantage in diagnostic accuracy could be found for imaging-guided quantitative sonography. The considerable diagnostic disagreement between both quantitative sonography techniques and dual X-ray absorptiometry could be confusing in daily clinical practice.
Absorptiometry, Photon↗