[Intravascular optical coherence tomography: differentiation of atherosclerotic plaques and quantification of vessel dimensions in crural arterial specimens]. / Intravaskuläre optische Kohärenztomographie: Unterscheidung verschiedener Plaquetypen und Vermessung von Gefässdimensionen in atherosklerotischen Unterschenkelarterien.

PURPOSE: Intravascular optical coherence tomography (OCT) is a new technique based on infrared light that visualizes the arteries with a resolution of 10-20 microm. Intravascular ultrasound (IVUS) is the current in vivo reference standard and provides a resolution of 100-150 microm. This study compared OCT to IVUS and histopathology with respect to the ability to differentiate atherosclerotic plaques and quantify vascular dimensions in peripheral crural arteries ex vivo. MATERIALS AND METHODS: 50 segments of atherosclerotic arteries derived from five amputated human lower extremities were examined. The different plaque types (fibrous, high-lipid content, calcified) were assigned by two independent examiners, and the sensitivity and specificity of OCT in comparison with histopathology as well as intra- and interobserver consensus were calculated. A comparison of OCT with IVUS addressed the parameters: luminal area (LA), vascular wall area (VA) and plaque area (PA). RESULTS: When comparing OCT and histopathology with respect to the differentiation of various plaque types, sensitivities of 81 % and specificities of 89 % for fibrous plaques, of 100 % and 93 % for lipid-rich plaques and of 80 % and 89 % for calcified plaques were achieved (overall correlation 83 %). Intra- and interobserver consensus was very high (kappa = 0.86 and kappa = 0.89, p < 0.001, respectively). There was also a high correlation between quantitative measurements (Bland-Altman plot [LA]: mean bias, 0.1 mm(2) accuracy +/- 1.8 mm(2), r = 0.95 [p < 0.001] Bland-Altman plot [VA]: mean bias, 0.3 mm(2) accuracy +/- 2.3 mm(2), r = 0.94 [p < 0.001] Bland-Altman plot [PA]: mean bias, 0.4 mm(2) accuracy +/- 2.3 mm(2), r = 0.80 [p < 0.01]. CONCLUSION: OCT allows the differentiation of atherosclerotic plaque types in crural arteries with high accuracy compared to histopathology. Quantitative measurements show a high correlation with IVUS, the current reference standard.

[Role of osteoporosis in trauma diagnostics]. / Stellenwert der Osteoporose in der traumatologischen Diagnostik.

PURPOSE: To evaluate the current bone mineral density (BMD) distribution in elderly patients hospitalized due to traumatic hip fracture and to assess the necessity of concomitant pharmacotherapy of underlying osteoporosis. MATERIALS AND METHODS: 58 female patients > or = 50 years (mean 81 years) with proven hip fracture were included. The diagnosis of fracture was established either by conventional radiography (CR) or by computed tomography (CT). BMD was assessed prospectively by means of dual energy X-ray absorption (DXA) measurement of the lumbar spine and/or femoral neck. DXA data was routinely achieved by analysis of T- and Z-values of the BMD. Distribution of BMD was assessed. Results for both measurement sites were compared using T-test and Pearson correlation analysis. RESULTS: 56/58 patients with proven hip fracture received DXA of the lumbar spine, 51 DXA of the femoral neck. The mean BMD was 0.829 +/- 0.137 g/cm (2) (lumbar spine) and 0.451 +/- 0.126 g/cm (2) (femur). T-values were - 2.8 +/- 1.14 (lumbar spine) and - 3.53 +/- 0.97 (femur). Compared to the normal distribution (lumbar spine), 53 patients (94.6 %) had diminished BMD (T < or = - 1). Of these 15 (26.8 %) had osteopenia (T > - 2.5) and 38 (67.9 %) had osteoporosis (T < or = - 2.5) according to WHO definition. With respect to femoral bone measurement, all patients (100 %) had diminished BMD (T < or = - 1), 9 patients (17.6 %) had osteopenia (T > - 2.5) and 42 patients (82.4 %) had osteoporosis (T < or = - 2.5). Results for different measurement sites differed significantly and were weakly correlated. CONCLUSION: This data indicate that diminished BMD in terms of osteopenia or osteoporosis is a frequent finding in hip fractures of elderly females. A large majority of these elderly patients therefore should be treated according to recent guidelines for treatment of osteoporosis. Our data indicate that this entity is potentially underdiagnosed and should be considered by radiologists as well as traumatologists.

[Correlation of different types of emphysema in high-resolution computed tomography (HR-CT) with the ILO-classification of coal workers pneumoconiosis]. / Zusammenhang zwischen Empyhsemtyp und Schweregrad der Pneumokoniose bei Bergleuten: Korrelation von HR-CT-Befunden und ILO-Klassifikation.

PURPOSE: The complaints of patients suffering from pneumoconiosis and the decrease in cardio-respiratory function tests are related to the major complications, emphysema or bronchitis, resp. to a lesser degree the complaints are directly influenced by the silicotic process itself. Up to now, no large study has analysed the correlation of different types and severity of emphysema with the ILO-classification of pneumoconiosis in miners. MATERIAL AND METHODS: In 104 miners the severity of pneumoconiosis was classified by ILO. By HR-CT the type and severity of emphysema was analysed using a 4-point-scale. The correlation of emphysema with the ILO-classification was tested with Pearson-correlation. RESULTS: The centrolobular emphysema was the dominant type with 59 %, but there was no dependence on the severity of pneumoconiosis. Only the paracicatricial emphysema had a significant correlation (p < 0.05) with the degree of large opacities. On the other hand, the paracicatricial emphysema was only detected in 32 %; under quantitative aspects it was seen to be less common than the centrolobular, the parapleural and the paraseptal emphysema (46 %). There was no significant correlation with the size and distribution of the small opacities and the different types of emphysema. CONCLUSIONS: Only the large opacities had a significant correlation with the appearance of paracicatricial emphysema. The other types of emphysema, especially, the dominant centrolobular type had no obvious association with pneumoconiosis. The multifactoral genesis of emphysema has to be taken into account.

[Multidetector-row CT of the lungs: Multiplanar reconstructions and maximum intensity projections for the detection of pulmonary nodules]. / Mehrschicht-Spiral-CT der Lunge: Multiplanare Rekonstruktionen und Maximum-Intensitäts-Projektionen in der Detektion von Lungenrundherden.

PURPOSE: The present study was performed to evaluate the utility of axial, coronal and sagittal multiplanar reformations (MPR) and maximum intensity projections (MIP) in the detection of pulmonary nodules as compared to axial standard reconstructions (SR). MATERIALS AND METHODS: 103 patients with suspicion or evidence of pulmonary nodules underwent multidetector-row computed tomography (MDCT; Somatom plus 4 Volume Zoom, Siemens, Germany) of the chest in a single-breath-hold technique. The raw data were acquired with a collimation of 1 mm and a pitch of 6 and underwent reconstruction with 0.6 mm increment. MPR and MIP in three planes [5 mm slice thickness (SL), 4 mm increment] were calculated from the raw data and compared to axial SR (5 mm SL). Three blinded observers evaluated the number, size and the quality of depiction of pulmonary nodules according to a 3-point confidence scale (1 = certain, 2 = probable, 3 = uncertain). Four patient groups were formed using the axial SR. Group 1 presenting no nodules, group 2 presenting probable nodules and group 3 presenting definitively lung nodules. Patients with more than 7 pulmonary nodules (group 4) were not included in the study. The 1 mm slice was used as the gold standard. RESULTS: Inter-observer correlation was good at r = 0.77. MIP were superior in the depiction of pulmonary nodules at a statistically significant level of p < 0.05 (mean values in group 3 = 2.58 to 1.97 and group 2 = 0.99 to 0.79 with MIP and SR, respectively). In four patients 6 additional lesions were identified with MIP that were missed with axial SR. Overall, with SR 72 nodules, with MPRs 78, and with MIPs 99 nodules were delineated. Pulmonary nodules larger than 5 mm in size were equally well depicted with both modalities, whereas lesions smaller than 5 mm in size were significantly better depicted with MIP (p < 0.05). Diagnostic confidence for all lesions was highest with MIP and least with SR. CONCLUSION: MIP reformations on the basis of MDCT data sets are superior in the depiction and diagnosis of pulmonary nodules as compared to axial standard reconstructions and MPR.

[Diagnostic value of different rectal contrast media in the detection of colorectal diseases by multi-slice CT]. / Diagnostische Wertigkeit verschiedener rektaler Darmkontrastierungen zur Erfassung von kolorektalen Erkrankungen im Multi-Detektor-CT.

PURPOSE: Assessment of 3 different rectal contrast agents (water, methylcellulose, ultrasound gel) for their suitability for colorectal imaging in multislice CT (MS-CT). METHODS: 115 patients with colorectal diseases underwent MS-CT with varying, rectal contrast agents in a prospective study. Images were assessed by 2 independent CT-experienced radiologists. 6 criterias were evaluated, using a 5-point scale. RESULTS: Methylcellulose (MC) proved to be significantly superior to ultrasound gel (US). Especially, differentiation of healthy and diseased bowel and bowel wall and lumen were aided, which was proven by quantitative analysis of attenuation values. Rectal distension is greater using MC or US than for water. More proximal parts of the colon could be better distended with water. The interobserver correlation was good (kappa 0.76). CONCLUSIONS: Rectal filling with MC significantly improves diagnostic confidence in colorectal examinations. Ease of administration and lack of problems suggest its use as a clinical routine tool.

[Value of multiplanar reformations (MPR)in multi-slice spiral CT of the lung]. / Wertigkeit multiplanarer Reformationen (MPR) in der Mehrschicht-Spiral-CT der Lunge.

PURPOSE: To evaluate the quality of multiplanar reformations (MPR) of multidetector spiral-CT (MD-CT) data sets of the chest based on anatomic criteria. METHODS: 90 patients with suspected or known diseases of the lung parenchyma underwent thoracic MD-CT with 1-mm collimation. Axial scans were reconstructed with 1-mm slice width and 0.6-mm reconstruction increment. Coronal and sagittal MPRs were reconstructed with 3, 5 and 8 mm thickness from the axial scans. Three blinded readers rated image quality based on several anatomic criteria and the presence of different artifacts using a 5-point scale. The scores for MPRs were compared with those of 5-mm thick axial scans. RESULTS: All anatomical structure were equally well depicted on MPRs as on axial scans with very good interobserver correlation (kappa 0.69-0.76). Only the lung parenchyma directly adjacent to the heart and the great vessels were visualized with limited quality due to cardiac pulsation artifacts. Advantages of sagittal MPRs include the sharper delineation of interlobar fissures and thus improved anatomic localization of a lesion. Coronal reformations also offer improved anatomic orientation in comparison with 5-mm axial scans. A slice thickness of 5 mm for MPRs yielded best results. CONCLUSIONS: MPRs allow an unrestricted assessment of the lung. Sagittal and coronal reformations improve the topographical visualization of chest anatomy.

[Low-dose spiral CT of the lung in the follow-up of non-malignant lung disease]. / Niedrigdosis-Spiral-CT des Thorax in der Verlaufskontrolle nichtmaligner Lungenerkrankungen.

PURPOSE: To assess image quality of chest CT with an 80 to 90 percent dose reduction in follow-up studies of patients with lung disease, dose and image quality of a low-dose protocol was investigated. MATERIALS AND METHODS: A follow-up low-dose CT (ND-CT, 120 kV, 10 mAs/slice, 3 mm slice thickness) was performed on 35 patients with non-malignant lung disease and compared with the initial standard dose CT (= SD-CT, 100 mAs/slice, 3 or 5 mm slice thickness). The dose was measured by thermo-luminescence in an Alderson phantom. Image quality was assessed by four independent radiologists in six perihilar, central and peripheral lung regions using a 4-point-scale ("very good", "good", "moderate", and "poor"). RESULTS: Effective dose was 0.5 mSv for ND-CT and 4.0 - 5.0 mSv for SD-CT. The ratings "very good"/"good" were given in the perihilar regions in ND-CT 97.5 % versus SD-CT 99.3 % (n. s.), in the central regions in ND-CT 96.4 % versus SD-CT 94.6 % (n. s.), and in the peripheral regions in ND-CT 70.0 % versus SD-CT 88.2 % (p < 0.01). CONCLUSION: Follow-up CT of pulmonary structures in patients with chronic lung disease can be performed with substantial dose reduction. A decrease of image quality may result in peripheral lung regions.

Pulmonary MRI--a new approach for the evaluation of febrile neutropenic patients with malignancies.

GOALS OF WORK: Immunocompromised patients with malignant diseases often suffer from pulmonary infections. Early detection of these life-threatening infections is crucial to start effective treatment. The gold standard for the diagnosis of these disorders is high-resolution computed tomography (HR-CT) of the chest. This method, however, has limitations, for instance, in the discrimination of early interstitial infiltrates and the use of X-rays. We conducted a study to determine the feasibility and sensitivity of magnetic resonance imaging (MRI) of the lung compared to HR-CT in immunocompromised patients with persistent fever in neutropenia and suspected pneumonia. MATERIALS AND METHODS: Between January 2003 and July 2004, 50 consecutive neutropenic patients with fever of unknown origin and negative chest X-ray were examined with HR-CT of the lungs. Patients with pulmonary infiltrates were further examined with MRI of the chest within 24 h after HR-CT using a specific lung protocol. In addition, microbiological testing was performed for the characterization of the causative pathogen. RESULTS: Of 50 patients, 35 had pulmonary infiltration according to HR-CT; these were examined with MRI of the lungs. MRI showed a high correlation (91%) with the findings in HR-CT. Both HR-CT and MRI were feasible in 94% of the examined patients. In 12 of 35 patients, fungal pathogens were identified in microbiological testing. CONCLUSIONS: MRI of the lungs is feasible in neutropenic patients with suspected pulmonary infection. Compared to HR-CT, MRI displays a high sensitivity in the detection of pulmonary infiltrates. MRI offers the opportunity of follow-up examinations without repeated X-ray exposure to the patient.

[Magnetic resonance imaging in the evaluation of pneumonia]. / Nachweis von pneumonischen Infiltraten mit der MRT.

Magnetic resonance imaging (MRI) of the lung is challenging because of substantial drawbacks. However, lung pathologies that are associated with increased attenuation values in CT enhance visualization in MRI: proton density is increased and tissue-air interfaces, resulting in susceptibility artifacts, are reduced in pneumonia, pneumonitis, edema, and carcinoma. On the other hand, many lung diseases result in shortness of breath, so that patients cannot hold their breath for long periods. Therefore, fast imaging techniques are required which should also allow for high spatial resolution so that small lesions can be detected. Calcifications and air pockets within lesions are not readily recognized with MRI. Thin section CT is standard for the diagnosis of pneumonia. With parallel imaging techniques, MRI examination of the lungs can be performed with short periods of breath holding, which allow for sub-centimeter resolution in the z-axis. Especially for follow-up examinations in immunocompromised patients and, in some instances, for the staging of malignant diseases (malignant pleural mesothelioma, lung cancer, respectively), MRI is very promising and may contribute to a decrease in the radiation exposure of the patients.

[Pulmonary manifestations in rheumatic systemic diseases]. / Pulmonale Manifestationen bei Erkrankungen des rheumatischen Formenkreises.

Collagen based vascular diseases with pulmonary involvement comprise rheumatoid arthritis, systemic lupus erythematosus, progressive systemic sclerosis, dermatomyositis and polymyositis, ankylosing spondylitis, Sjögren's syndrome, and mixed connective tissue diseases. The different characteristics of pulmonary involvement are described. In such circumstances, early recognition of lung involvement is of considerable significance and the relationship to the corresponding disease has to be made. Frequently unrecognised pulmonary involvement ends up as fibrosis with irreversible deficits in respiratory function.

[Image analysis in multislice spiral CT of the lung with MPR and MIP reconstructions]. / Bildanalyse bei der Mehrschicht-Spiral-CT der Lunge mit MPR- und MIP-Rekonstruktionen.

PURPOSE: To test, whether axial, coronal and sagittal MIP and MPR reconstructions of diagnostic quality can be obtained from 1-mm collimation MSCT data of the chest for the evaluation of thoracic anatomy and pathology. MATERIALS AND METHODS: 1-mm collimation MSCT scans were obtained with a pitch of 6 in an acrylic phantom and in 20 patients. Axial images were reconstructed with 0.6-mm increment. Multiplanar reformations (MPRs) and sliding thin-slab maximum intensity projections (STS-MIPs) were reconstructed in axial, coronal and sagittal planes. Images were printed in lung windows and evaluated by three readers by using a standardized evaluation scheme. RESULTS: Overall, both methods allowed good visualization of anatomic structures. MIP was superior for visualization of the pulmonary arteries (p < 0.05) while central and peripheral bronchi and the lung parenchyma were better depicted on multiplanar reconstructions. A confident diagnosis of thoracic pathology was feasible using both modalities, however MIPs appeared less usefull for evaluation of gross parenchymal abnormalities, such as pneumonic infiltrates or fibrotic changes. No significant difference in the degree of motion artifacts were detected between both modalities. CONCLUSION: MSCT data sets are ideally suited for generating MPR and MIP reconstructions. While MIPs are superior for the evaluation of thoracic vessels, MPR is advantageous for visualizing central and peripheral bronchi and the pulmonary parenchyma.

Staging of rectal cancer: diagnostic potential of multiplanar reconstructions with MDCT.

OBJECTIVE: The purpose of this study was to evaluate whether multiplanar reconstructions (MPRs) of MDCT could improve local staging of rectal cancer. CONCLUSION: Adding MPRs, on the basis of the MDCT data sets, provides definite improvements in the accurate local staging of rectal cancer compared with standard axial reconstructions alone.

Functional variables associated with the clinical grade of dyspnoea in coal miners with pneumoconiosis and mild bronchial obstruction.

OBJECTIVES: Dyspnoea is a common symptom in coal miners with pneumoconiosis. Among others, gas exchange disturbances due to airway obstruction or mismatch between ventilation and perfusion may be underlying mechanisms. The validation of dyspnoea by the degree of airway obstruction is controversial, because the extent of airway obstruction often does not correlate with the clinical grade of breathlessness. METHODS: The association was investigated between breathlessness (self reported, on a six point scale) and indices of submaximal spiroergometry in 66 coal workers with radiographically confirmed pneumoconiosis (International Labour Organisation (ILO) grade of profusion > or =1/0, mean (SD) age 64 (5.5) years, mean (SD) forced expired volume in 1 second (FEV(1)) 77.5 (22.9) % predicted). RESULTS: The clinical degree of breathlessness was independently associated with minute ventilation/oxygen consumption (VE/VO(2)) ratio (beta 0.423, 95% confidence interval (95% CI) 0.18 to 0.67, p=0.001) and smoking (beta 0.318, 95% CI 0.21 to 1.79, p=0.014) in a multiple linear regression analysis. The VE/VO(2) ratio (beta 0.556, 95% CI 0.20 to 0.90, p=0.003) was also the best predictor of breathlessness when only coal miners with airway obstruction (FEV(1) < 80% predicted) were analyzed. CONCLUSION: The VE/VO(2) ratio as a measurement of mismatch between ventilation and perfusion predicted the clinical grade of breathlessness better than measurements of bronchial obstruction at rest in coal workers with pneumoconiosis.

Multislice helical CT of focal and diffuse lung disease: comprehensive diagnosis with reconstruction of contiguous and high-resolution CT sections from a single thin-collimation scan.

OBJECTIVE: We tested breath-held 1-mm multislice helical CT for obtaining both contiguous and high-resolution CT sections of the chest from a single set of raw data. SUBJECTS AND METHODS: Seventy patients with suspected focal and diffuse lung disease were allocated into two groups for comparison. The first group (n = 35) underwent multislice helical CT of the chest with 1-mm collimation and a pitch of 6. From the raw data, 5-mm contiguous and 1.25-mm high-resolution CT sections were reconstructed. The second group (n = 35) underwent conventional single-slice helical CT and high-resolution CT. High-resolution CT sections and 5-mm scans were rated for overall image quality, spatial resolution, subjective signal-to-noise ratio, diagnostic value, depiction of bronchi and parenchyma, and motion and streak artifacts. The 5-mm scans were also rated for contrast resolution and depiction of the heart and vessels. Radiation dose was calculated. RESULTS: We rated 5-mm multislice helical CT superior to 5-mm single-slice helical CT, having a significantly higher total score (p = 0.0001). No significant difference (p = 0.986) was found between multislice and single-slice high-resolution CT sections. Radiation dose was 5.55 mSv for multislice helical CT and 5.50 mSv for single-slice helical CT. CONCLUSION: Contiguous chest scans of superior quality and high-resolution CT sections of equal image quality compared with single-slice helical CT can be obtained using multislice helical CT. Therefore, a comprehensive diagnosis is feasible in patients with suspected focal and diffuse lung disease by obtaining a single scan.

[Imaging of the thorax with multislice spiral CT]. / Bildgebung des Thorax mit der Mehrschicht-Spiral-CT.

With multislice spiral computed tomography (MSCT), existing indications for performing CT of the chest are strengthened and new applications are emerging. The high speed of MSCT improves efficiency, image quality and patient comfort of "routine" imaging of the chest. The ability to cover large volumes with thin slices improves the evaluation of mediastinal lymph nodes and pulmonary nodules and allows for high-quality secondary reconstruction. If a comprehensive diagnosis of the mediastinal structures and the pulmonary parenchyma is desired, MSCT for the first time allows reconstruction of contiguous and high-resolution (HRCT) sections from the same set of thin-collimation raw data. This way, contiguous chest images of superior and HRCT sections of equal image quality compared to conventional CT scanning can be obtained. Vascular protocols greatly benefit from the high speed of MSCT: For imaging the thoracic aorta or pulmonary emboli (PE), the amount of contrast material can be substantially reduced. Owing to thin collimation, the detection rate of small peripheral emboli can be significantly increased. If indicated, the entire subphrenic venous system can be evaluated during the same session, without additional contrast material.