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1.
Indian J Med Sci ; 59(11): 471-9, 2005 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-16340146

RESUMEN

BACKGROUND: G-tolerance assessment is an essential element of both military pilot and pilot candidate evaluation. AIMS: Attempt at prediction of individual relaxed + Gz tolerance on the basis of head-up tilt (HUT) testing. SETTINGS AND DESIGN: In two stages, 20 healthy men at the mean age 21.5 years took part in this study. The first stage, a 45 min, HUT test was performed using the Westminster protocol. During the second stage each underwent a centrifuge evaluation in response to gradual onset rate profiles. METHODS AND MATERIAL: In each subject, heart rate (HR) and blood pressure (BP) before and at 2, 15 and 45 min of the tilt-test were recorded. The gravity-load centrifuge (GOR) studies were carried out [following the standard GOR programme, at 0.1 G%divide;s rate of gravity load increase until the gravity load tolerance limit (loss of peripheral vision) was reached]. STATISTICAL ANALYSIS USED: Relationships between variables were explored using Kendall's tau-B correlation coefficient. The critical P-level was one-tailed 0.05. RESULTS: In four of 20 subjects (20%), vasovagal syncope occurred during the tilt test. G-level tolerance of this group (of +Gz accelerations) lay in the range from +4 to +8.1 Gz, (+5.72 ? 0.86 Gz average) and was comparable to the group without syncope. Loss of consciousness did not occur in any subjects during the centrifuge test. No statistically significant correlation was observed between HR and BP during tilt test and tolerance to +Gz accelerations. CONCLUSIONS: The result of tilt testing, carried out according to the Westminster protocol, was not useful in predicting individual tolerance to +Gz gravity loads.


Asunto(s)
Hipergravedad , Pruebas de Mesa Inclinada , Adulto , Medicina Aeroespacial , Centrifugación , Humanos , Masculino
2.
Acta Radiol ; 45(5): 499-503, 2004 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-15515509

RESUMEN

PURPOSE: To describe an unusual enhancement pattern of hepatosplenic candidiasis (HSC) liver lesions in biphasic spiral liver computed tomography (CT). MATERIAL AND METHODS: Twenty-one patients with suspected HSC were scanned with a biphasic liver CT perfusion protocol. The liver lesions detected were assessed for their morphology and enhancement pattern during both perfusion phases. A liver biopsy was performed in 11/21 patients. RESULTS: The majority of hepatic lesions in 15/21 patients showed the well-known abscess-like pattern. In 6/21 patients an uncommon central contrast enhancement with a peripheral double ring was detected in the arterial phase. In some cases the lesions showed decreased diameter or even seemed to disappear completely in the portalvenous phase. CONCLUSIONS: CT in the arterial phase showed an unusual enhancement pattern of liver lesions in HSC. Scanning only in the portalvenous phase implies possible pitfalls, because lesions may be overlooked or undersized. Therefore, biphasic liver CT is considered essential in the diagnosis and follow-up of HSC in clinical practice.


Asunto(s)
Candidiasis/diagnóstico por imagen , Hepatopatías/diagnóstico por imagen , Hígado/diagnóstico por imagen , Intensificación de Imagen Radiográfica , Enfermedades del Bazo/diagnóstico por imagen , Tomografía Computarizada por Rayos X/métodos , Adulto , Candidiasis/patología , Humanos , Hígado/patología , Hepatopatías/patología , Persona de Mediana Edad
3.
Aviat Space Environ Med ; 74(6 Pt 1): 654-8, 2003 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-12793538

RESUMEN

INTRODUCTION: Levels of serum lipids and antioxidative agents are known to be important in people at risk for heart disease, but less is known about these factors in clinically healthy populations such as pilots. METHODS: We measured the activities of red blood cell antioxidative enzymes, total antioxidative activity in serum (TAS), and lipid concentrations in 229 fighter pilots in the Polish Air Force. Measured variables included total cholesterol (T-CH), as well as its low-density and high-density lipid components (LDL-CH and HDL-CH, respectively). We then calculated the atherogenicity index (T-CH/HDL-CH). In addition, we measured the activities of superoxide dismutase (SOD), glutathione peroxidase (GPx), and TAS. RESULTS: The mean lipid concentrations in the group studied fell in the expected normal ranges. However, only 22.2% of pilots had normal or below-normal lipid levels, while the majority displayed some level of hyperlipidemia (40.6% mild, 30.4% moderate, 7.4% severe). The mean atherogenic index was > 5. The mean activities of SOD, GPx, and TAS exceeded the upper limits of normal. Individuals with T-CH > 7.7 mmol x L(-1) had low activities of SOD, GPx, and TAS. Presence of normal T-CH concentration did not exclude an abnormal atherogenicity index. CONCLUSIONS: Normal T-CH concentration in a healthy population does not exclude a concomitant increase in LDL-CH and/or reduction in HDL-CH and an abnormal atherogenicity index. Those who provide medical support to pilots should emphasize the importance of a proper diet, physical activity, and use of hypolipemic drugs when indicated.


Asunto(s)
Glutatión Peroxidasa , Superóxido Dismutasa , Colesterol/sangre , Humanos , Lípidos/sangre
4.
Rofo ; 174(7): 862-6, 2002 Jul.
Artículo en Alemán | MEDLINE | ID: mdl-12101476

RESUMEN

PURPOSE: To determine the incidence of acute pulmonary emboli extending across the bifurcation of the main pulmonary artery, lobar arteries or segmental arteries (interpulmonary, interlobar or intersegmental saddle emboli, respectively). METHODS: 128 patients with clinically suspected acute pulmonary embolism underwent electron beam tomography (EBT). 140 scans were acquired in the continuous volume scanning mode (3 mm slice thickness). 100 ml of contrast material were intravenously administered. Studies were reviewed for the presence of acute pulmonary embolism and the number and location of interpulmonary, interlobar or intersegmental saddle emboli. Saddle emboli were defined as emboli extending across the bifurcation of a vessel into both branches by at least 5 mm each. RESULTS: 30 of 128 (23.4 %) patients (15 men; mean age 59 +/- 17 years) had acute pulmonary embolism. One or more saddle emboli were present in 20 of 30 patients (66.7 %), a total of 77 saddle emboli were detected ranging from 1 to 10 per patient. Distribution of the saddle emboli in the 20 patients was as follows: 5 interpulmonary, 28 interlobar and 44 intersegmental. CONCLUSIONS: Pulmonary saddle emboli are present in the majority of patients with acute pulmonary embolism. They are often multiple and may be found at different levels of the pulmonary arterial vasculature.


Asunto(s)
Embolia Pulmonar/diagnóstico por imagen , Tomografía Computarizada por Rayos X , Enfermedad Aguda , Adulto , Anciano , Anciano de 80 o más Años , Femenino , Humanos , Masculino , Persona de Mediana Edad , Arteria Pulmonar/diagnóstico por imagen , Sensibilidad y Especificidad
5.
Eur Radiol ; 12(8): 2107-11, 2002 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-12136331

RESUMEN

Our objective was to compare a single-slice CT (SS-CT) scanner with a multi-slice CT (MS-CT) scanner in the depiction of osseous anatomic structures and fractures of the upper cervical spine. Two cervical spine specimens with artificial trauma were scanned with a SS-CT scanner (HighSpeed, CT/i, GE, Milwaukee, Wis.) by using various collimations (1, 3, 5 mm) and pitch factors (1, 1.5, 2, 3) and a four-slice helical CT scanner (LightSpeed, QX/i, GE, Milwaukee, Wis.) by using various table speeds ranging from 3.75 to 15 mm/rotation for a pitch of 0.75 and from 7.5 to 30 mm/rotation for a pitch of 1.5. Images were reconstructed with an interval of 1 mm. Sagittal and coronal multiplanar reconstructions of the primary and reconstructed data set were performed. For MS-CT a tube current resulting in equivalent image noise as with SS-CT was used. All images were judged by two observers using a 4-point scale. The best image quality for SS-CT was achieved with the smallest slice thickness (1 mm) and a pitch smaller than 2 resulting in a table speed of up to 2 mm per gantry rotation (4 points). A reduction of the slice thickness rather than of the table speed proved to be beneficial at MS-CT. Therefore, the optimal scan protocol in MS-CT included a slice thickness of 1.25 mm with a table speed of 7.5 mm/360 degrees using a pitch of 1.5 (4 points), resulting in a faster scan time than when a pitch of 0.75 (4 points) was used. This study indicates that MS-CT could provide equivalent image quality at approximately four times the volume coverage speed of SS-CT.


Asunto(s)
Vértebras Cervicales/diagnóstico por imagen , Fracturas de la Columna Vertebral/diagnóstico por imagen , Tomografía Computarizada por Rayos X/métodos , Humanos , Procesamiento de Imagen Asistido por Computador
6.
Rofo ; 174(3): 273-82, 2002 Mar.
Artículo en Alemán | MEDLINE | ID: mdl-11885002

RESUMEN

Multislice CT systems allow the simultaneous acquisition of multiple slices per gantry rotation. In combination with faster gantry rotation times of 0.5 seconds, the abdominal structures can be displayed in higher spatial and temporal resolution. In MS-CT of the liver it is possible to scan the entire organ with an optimal slice thickness of 2 - 3 mm within a defined perfusion phase in less than 10 seconds. This results in an improved detection and characterization of focal liver lesions. A high-quality, 3-dimensional reconstruction of the hepatic arterial and portalvenous system is obtained with the same data set. The diagnostic use of the simultaneously acquired perfusion data will lead to a better characterization of focal liver lesions in the future. The diagnostics of the pancreas also profits from MS-CT, especially for the detection of small tumors and the evaluation of resectability of a pancreatic carcinoma. All abdominal structures can be displayed in a coronal view without loss of image quality because of the almost isotropic voxels obtained. This proves to be beneficial for the preoperative diagnostics of renal cell carcinomas, especially if the tumor extension into adjacent organs (e. g., liver or spleen) in the longitudinal direction has to be evaluated. The multiplanar display and the sophisticated 3-dimensional reconstruction tools have a substantial value for the abdominal CT angiography. It proves to have a major diagnostic impact on acute abdominal aortic and visceral arterial diseases because even large distances in the z-direction can be covered with high spatial resolution.


Asunto(s)
Neoplasias Abdominales/diagnóstico por imagen , Procesamiento de Imagen Asistido por Computador/tendencias , Imagenología Tridimensional/tendencias , Intensificación de Imagen Radiográfica/tendencias , Tomografía Computarizada por Rayos X/tendencias , Neoplasias Abdominales/irrigación sanguínea , Predicción , Humanos , Flujo Sanguíneo Regional/fisiología , Sensibilidad y Especificidad
7.
Rofo ; 173(10): 938-41, 2001 Oct.
Artículo en Alemán | MEDLINE | ID: mdl-11588683

RESUMEN

UNLABELLED: Impact of different iodine concentrations on abdominal enhancement in biphasic multislice helical CT (MS-CT). PURPOSE: To evaluate if different iodine concentrations of a contrast material (c.m.) have an impact on abdominal enhancement in MS-CT during the arterial (AP) and portal venous phase (PVP). MATERIALS AND METHODS: 75 patients underwent biphasic CT of the abdomen. They were assigned to three equally sized groups. For all patients a non-ionic c.m. (iopromide, Ultravist, Schering AG, Berlin) with different iodine concentrations and a constant total iodine load of 37 g with an injection flow rate of 4 ml/s was used. The volume of the c.m. differed depending on the iodine concentrations: group 1 (123 ml of 300 mgl/ml); group 2 (112 ml of 335 mgl/ml); group 3 (100 ml of 370 mgl/ml). The scan delay was optimized by using a bolus tracking device. The groups were compared concerning their mean enhancement of aorta, spleen, pancreas, and liver in the AP and PVP. RESULTS: The comparison of the three groups showed an improved enhancement in aorta, spleen, and pancreas during the AP by using the higher c.m. concentrations. In the PVP the c.m. enhancement of aorta, liver, spleen, and pancreas was independent of the administered c.m. concentration. CONCLUSION: Higher iodine concentrations of c.m. have a positive impact on abdominal enhancement during the AP. The concentration has no influence on the enhancement during the PVP of abdominal MS-CT.


Asunto(s)
Medios de Contraste/administración & dosificación , Yohexol/análogos & derivados , Intensificación de Imagen Radiográfica , Radiografía Abdominal , Tomografía Computarizada por Rayos X , Adulto , Anciano , Relación Dosis-Respuesta a Droga , Femenino , Humanos , Inyecciones Intravenosas , Yohexol/administración & dosificación , Masculino , Persona de Mediana Edad , Sensibilidad y Especificidad
8.
Scand J Urol Nephrol ; 35(3): 252-3, 2001 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-11487084

RESUMEN

Placement of an aortic wallstent for treatment of an abdominal aortic aneurysm (AAA) is a frequent therapeutic measure. Whereas AAA is known to mimic renal colic, aortic wallstent dislocation is a novel diagnostic problem. Herein, we report the first case of a patient with a dislocated aortic wallstent and subsequent aneurysm rupture and discuss appropriate diagnostic measures.


Asunto(s)
Aneurisma de la Aorta Abdominal/complicaciones , Aneurisma de la Aorta Abdominal/diagnóstico por imagen , Rotura de la Aorta/diagnóstico por imagen , Rotura de la Aorta/etiología , Cólico/diagnóstico por imagen , Enfermedades Renales/diagnóstico por imagen , Falla de Prótesis , Stents , Anciano , Anciano de 80 o más Años , Diagnóstico Diferencial , Humanos , Masculino , Radiografía
9.
Rofo ; 173(6): 528-35, 2001 Jun.
Artículo en Alemán | MEDLINE | ID: mdl-11471294

RESUMEN

AIM: To determine the value of multi-slice CT for the diagnosis of acute pulmonary embolism and an underlying venous thrombosis. METHODS: 70 patients with clinically suspected acute pulmonary embolism were examined. Using multi-slice CT a combined examination of the pulmonary arteries and the veins of the lower limb, pelvis and abdomen was performed. Only one single bolus of 150 ml iopromid 300 was injected into a cubital vein with a flow of 4 ml/s. First, the pulmonary arteries were scanned with a slice thickness of 2.5 mm and a pitch of 1.5. On arrival of the contrast medium at the popliteal veins, indicated by bolus trakking, the veins of the lower limbs up to the end of the inferior vena cava were imaged using a slice thickness of 3.75 mm and a pitch of 1.5. The results could be compared with a ventilation-perfusion scan in 48 cases, with a Doppler ultrasound examination in 46 cases, and with a venography in 10 cases. Furthermore, the image quality of all arterial and venous regions was subjectively assessed. RESULTS: In all patients who underwent multi-slice CT the pulmonary arteries as well as the veins of the lower half of the body could be recorded completely. Regarding the pulmonary arteries the image quality showed excellent results for the central and segmental arteries. The region up to the 3rd division in subsegmental branches could be sufficiently judged. More peripherally, a diagnostic assessment was not possible. The image quality of the veins was excellent in all sections, except the calf, where a reliable diagnosis could not be made. The comparison with the other techniques confirmed the superiority of multi-slice CT concerning the central and segmental pulmonary arteries and the veins from the popliteal vein to the inferior vena cava. In contrast, peripheral pulmonary emboli can be detected more certainly in ventilation/perfusion scans. The veins of the calf can be evaluated more reliably with venography. CONCLUSION: Multi-slice CT proved to be an outstanding tool in the diagnosis of acute pulmonary embolism. The clinically suspected disease and a causing venous thrombosis can be detected in a fast and reliable way. At present, multi-slice CT is not suitable for the recognition of peripheral emboli. However, expected technical developments hold promise for future improvements.


Asunto(s)
Embolia Pulmonar/diagnóstico por imagen , Tomografía Computarizada por Rayos X , Trombosis de la Vena/diagnóstico por imagen , Adulto , Anciano , Anciano de 80 o más Años , Femenino , Humanos , Masculino , Persona de Mediana Edad , Flebografía , Arteria Pulmonar/diagnóstico por imagen , Sensibilidad y Especificidad
10.
Eur J Radiol ; 33(1): 41-9, 2000 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-10674789

RESUMEN

OBJECTIVE: Evaluation of different contrast-enhanced MR angiography imaging protocols for visualization of the entire aorta in breath-hold technique. METHODS AND PATIENTS: Three different CE (0.15 mmol/kg) MRA protocols were evaluated by phantom and patient studies: (1) two separate MRA with conventional application of the body-phased array coil; (2) a single-shot MRA with modified application of the body-phased array coil; (3) a single-shot MRA with the body coil. Duplex sonography, CTA and DSA were used as standard of reference. RESULTS: In all examinations the entire aorta could be visualized. The best SNR was acquired with protocol (1). The SNR of protocol (2) was reduced if the sagittal body diameter of the patient was greater than 20 cm and decreased significantly with diameters over 30 cm. By the use of protocol (3) the SNR was notably poor. The quality scored for the visualization of the entire aorta was 97.5% (protocol 1); 92.5% (protocol 2); and 80.0% (protocol 3). CONCLUSION: In most cases the modified application of the body-phased array coil allows the imaging of the entire aorta as a single-shot 3D CE MRA in diagnostic quality.


Asunto(s)
Enfermedades de la Aorta/diagnóstico , Angiografía por Resonancia Magnética/métodos , Adolescente , Adulto , Anciano , Disección Aórtica/diagnóstico , Angiografía de Substracción Digital , Aneurisma de la Aorta/diagnóstico , Coartación Aórtica/diagnóstico , Constitución Corporal , Medios de Contraste , Estudios de Factibilidad , Femenino , Gadolinio DTPA , Humanos , Aumento de la Imagen/instrumentación , Aumento de la Imagen/métodos , Procesamiento de Imagen Asistido por Computador/instrumentación , Procesamiento de Imagen Asistido por Computador/métodos , Angiografía por Resonancia Magnética/instrumentación , Masculino , Persona de Mediana Edad , Fantasmas de Imagen , Tomografía Computarizada por Rayos X/métodos , Ultrasonografía Doppler Dúplex
11.
Rofo ; 172(11): 927-33, 2000 Nov.
Artículo en Alemán | MEDLINE | ID: mdl-11142127

RESUMEN

PURPOSE: The aim of this study is to determine the optimal scan parameters for the evaluation of experimental vascular stenoses with a multislice-helical CT. MATERIAL AND METHODS: A vascular phantom consisting of four tubes with an inner diameter of 8 mm and with experimental stenoses of 50%, 75% and 90% was scanned in different tube orientations using a multislice-CT scanner (LightSpeed QX/i, GE, Milwaukee, USA). Examinations were performed with increasing collimations (1.25-5 mm), tube currents (100-300 mA) and two different table speeds (0.75 HQ mode and 1.5 HS mode). RESULTS: The most exact measurements were obtained in tubes angulated parallel to the scan direction with a collimation of 2.5 mm in the HQ mode (7.5 mm/rot.). An almost equivalent accuracy was obtained in the HS mode (15 mm/rot.) with a collimation of 2.5 mm when higher tube currents (300 mA) were employed. The degree of stenoses was overestimated when the tube was angulated perpendicular to the z-axis. CONCLUSION: Multislice-CT provides a good detection rate of vascular stenoses especially at 0 degree and also at 45 degrees angulation in the HQ mode. The use of the HS mode with higher tube currents allows scanning of longer distances with almost identical accuracy.


Asunto(s)
Angiografía/métodos , Procesamiento de Imagen Asistido por Computador , Fantasmas de Imagen , Tomografía Computarizada por Rayos X/métodos , Humanos , Reproducibilidad de los Resultados , Sensibilidad y Especificidad
12.
Radiology ; 213(3): 881-8, 1999 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-10580970

RESUMEN

PURPOSE: To determine if magnetic resonance (MR) imaging can help determine the therapeutic approach in women with breast cancer. MATERIALS AND METHODS: Preoperative contrast-enhanced MR imaging of the breast was performed in 463 patients with probably benign lesions (n = 63), suspicious lesions (n = 230), or lesions highly suggestive of malignancy (n = 170) per established clinical, mammographic, and/or ultrasonographic (US) criteria. T1-weighted fast low-angle shot MR imaging was performed before and after administration of gadopenetetate dimeglumine. MR imaging findings were correlated with other imaging results and histopathologic findings. Special attention was paid to multifocality and multicentricity. RESULTS: Histopathologic analysis revealed 143 benign and 405 malignant lesions. The sensitivity, specificity, and accuracy were 58%, 76%, and 62% for clinical examination; 86%, 32%, and 72% for conventional mammography; 75%, 80%, and 76% for US; and 93%, 65%, and 85% for contrast-enhanced MR imaging. Multifocality in 30 of 42 patients, multicentricity in 24 of 50 patients, and additional contralateral carcinomas in 15 of 19 patients were depicted with MR imaging alone. Due to the MR imaging findings, therapy was changed correctly in 66 patients (14.3%); unnecessary open biopsy was performed in 16 patients (3.5%). CONCLUSION: Contrast-enhanced MR imaging of the breast is highly sensitive for invasive breast cancer. MR imaging may reveal unsuspected multifocal, multicentric, or contralateral breast carcinoma and result in therapy changes.


Asunto(s)
Neoplasias de la Mama/diagnóstico , Carcinoma Ductal de Mama/diagnóstico , Imagen por Resonancia Magnética , Adulto , Anciano , Mama/patología , Neoplasias de la Mama/patología , Neoplasias de la Mama/cirugía , Carcinoma Ductal de Mama/patología , Carcinoma Ductal de Mama/cirugía , Medios de Contraste , Femenino , Gadolinio DTPA , Humanos , Mamografía , Persona de Mediana Edad , Estadificación de Neoplasias , Neoplasias Primarias Múltiples/diagnóstico , Neoplasias Primarias Múltiples/patología , Neoplasias Primarias Múltiples/cirugía , Pronóstico , Ultrasonografía Mamaria
13.
Radiologe ; 39(11): 979-87, 1999 Nov.
Artículo en Alemán | MEDLINE | ID: mdl-10602804

RESUMEN

UNLABELLED: Acute diseases of the central arteries require an immediate investigation. An efficient, fast and reliable diagnosis is necessary because of the high mortality, if the patient remains untreated. These requirements are perfectly fulfilled by the new CT-techniques. METHODS: Suspected aortic diseases were examined with a new multi-slice helical CT. The thoracic or the abdominal aorta as well as the entire vascular tree from the supra-aortic branches to the inguinal arteries were investigated with different CT protocols. The slice-thickness and the scan mode were changed while the total examination time was kept constant for the first two groups. In the third group a monophasic examination was compared to a biphasic one. RESULTS: In the diagnosis of acute aortic diseases multi-slice helical CT proved to be a fast and reliable method with all scan protocols. The objective measurements of contrast homogeneity and image quality were comparable in the first two groups. The monophasic contrast medium injection protocol was superior to the biphasic administration mode. CONCLUSIONS: Multi-slice helical CT appears to be a very effective approach for the diagnosis of acute aortic diseases and seems to be the new gold standard.


Asunto(s)
Aneurisma de la Aorta Torácica/diagnóstico por imagen , Disección Aórtica/diagnóstico por imagen , Rotura de la Aorta/diagnóstico por imagen , Tomografía Computarizada por Rayos X/métodos , Enfermedad Aguda , Aorta Torácica/diagnóstico por imagen , Estenosis de la Válvula Aórtica/diagnóstico por imagen , Aortografía/instrumentación , Aortografía/métodos , Medios de Contraste , Estudios de Seguimiento , Humanos , Tomografía Computarizada por Rayos X/instrumentación
14.
Radiologe ; 39(11): 971-8, 1999 Nov.
Artículo en Alemán | MEDLINE | ID: mdl-10602803

RESUMEN

PURPOSE: Scan protocol optimization and value of a multi-row-detector helical CT (MS-CT) in comparison to a single-row-detector spiral CT (SS-CT) for imaging of focal liver lesions. MATERIALS AND METHODS: The ability of a MS-CT with different scan parameters (slice thickness, scan mode, table-speed, reconstruction interval) for the detection of low-contrast objects was evaluated with a liver phantom and compared to a SS-CT. The clinical value (detection and characterization) of MS-CT with various slice thicknesses (3.75, 5, 7.5 mm) was compared intraindividually in 20 patients with a total of 43 benign and malignant lesions. RESULTS: In the experimental study the MS-CT reached the same detection rates for low-contrast objects despite a three-times faster scan-time compared to a SS-CT. The slice thicknesses of 3.75 and 5 mm proved to be optimal and were superior to a thickness of 7.5 mm for the detection and characterization of liver lesions. A distinct separation between arterial and portal venous phase was achieved by this protocol. CONCLUSION: The MS-CT allows a reliable acquisition of the entire liver parenchyma in defined perfusion phases. It improves the detection and characterization of focal liver lesions with optimized scan parameters with a significantly faster scan time than with the SS-CT.


Asunto(s)
Hígado/diagnóstico por imagen , Tomógrafos Computarizados por Rayos X , Tomografía Computarizada por Rayos X/instrumentación , Adulto , Carcinoma Hepatocelular/diagnóstico por imagen , Medios de Contraste/administración & dosificación , Femenino , Humanos , Yohexol/administración & dosificación , Yohexol/análogos & derivados , Neoplasias Hepáticas/diagnóstico por imagen , Masculino , Persona de Mediana Edad , Fantasmas de Imagen/estadística & datos numéricos , Tomógrafos Computarizados por Rayos X/estadística & datos numéricos , Tomografía Computarizada por Rayos X/métodos , Tomografía Computarizada por Rayos X/estadística & datos numéricos
15.
Rofo ; 171(2): 100-5, 1999 Aug.
Artículo en Alemán | MEDLINE | ID: mdl-10506882

RESUMEN

PURPOSE: To evaluate the feasibility and diagnostic value of there different MR angiographic imaging techniques for the assessment of the central body veins. METHODS: 25 investigations of the central veins were performed with an ECG-triggered black-blood HASTE sequence, a segmented 2D cine FLASH sequence and a contrast-enhanced 3D-FISP angiography. The results of the MR-studies were compared with those of spiral CT or venography. RESULTS: The HASTE sequence was suitable for the assessment of the complete central body vein system also in less cooperative patients. The combination with the 2D cine FLASH sequence enabled the detection of intravascular tumors or thromboses and the graduation of subtotal occlusions. The involvement of the right atrium was proved in 2/2 cases. The attachment at the vessel wall could be assessed. Only contrast-enhanced 3D MRA visualized the renal veins and complex collaterals sufficiently. But this procedure has to be done in a strict breath-hold technique. CONCLUSION: In the present study all thromboses and tumor cones of the central body veins were detected with the combined use of HASTE/Cine FLASH. For the assessment of complex collaterals and the renal vessels the application of contrast-enhanced 3D-MRA techniques is necessary.


Asunto(s)
Angiografía por Resonancia Magnética/métodos , Venas Cavas/patología , Adolescente , Adulto , Anciano , Angiografía de Substracción Digital , Medios de Contraste , Femenino , Gadolinio DTPA , Humanos , Angiografía por Resonancia Magnética/instrumentación , Imagen por Resonancia Cinemagnética/instrumentación , Imagen por Resonancia Cinemagnética/métodos , Masculino , Persona de Mediana Edad , Variaciones Dependientes del Observador , Tomografía Computarizada por Rayos X , Venas Cavas/diagnóstico por imagen , Trombosis de la Vena/diagnóstico
16.
Rofo ; 171(3): 219-25, 1999 Sep.
Artículo en Alemán | MEDLINE | ID: mdl-10520332

RESUMEN

PURPOSE: Presentation and evaluation of slice sensitivity profile and pixel noise of multi-slice CT in comparison to single-slice CT. METHODS: Slice sensitivity profiles and pixel noise of a multi-slice CT equipped with a 2D matrix detector array and of a single-slice CT were evaluated in phantom studies. RESULTS: For the single-slice CT the width of the slice sensitivity profiles increased with increasing pitch. In spite of a much higher table speed the slice sensitivity profiles of multi-slice CT were narrower and did not increase with higher pitch. Noise in single-slice CT was independent of pitch. For multi-slice CT noise increased with higher pitch and for the higher pitch decreased slightly with higher detector row collimation. CONCLUSIONS: Multi-slice CT provides superior z-resolution and higher volume coverage speed. These qualities fulfill one of the prerequisites for improvement of 3D postprocessing.


Asunto(s)
Procesamiento de Imagen Asistido por Computador/instrumentación , Tomografía Computarizada por Rayos X/instrumentación , Artefactos , Diseño de Equipo , Humanos , Sensibilidad y Especificidad , Tecnología Radiológica/instrumentación
17.
Rofo ; 170(6): 587-90, 1999 Jun.
Artículo en Alemán | MEDLINE | ID: mdl-10420910

RESUMEN

Hepatosplenic candidiasis is a severe complication encountered in immuno-compromised patients. Different imaging techniques can establish the diagnosis. After an introduction to the pathophysiological and clinical principles, the role of plain radiography, radionuclide scans, ultrasound, computed tomography and magnetic resonance imaging is discussed.


Asunto(s)
Candidiasis/diagnóstico , Diagnóstico por Imagen , Hepatopatías/diagnóstico , Infecciones Oportunistas/diagnóstico , Enfermedades del Bazo/diagnóstico , Humanos , Hígado/patología , Sensibilidad y Especificidad , Bazo/patología
18.
Radiology ; 211(1): 51-8, 1999 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-10189453

RESUMEN

PURPOSE: To optimize and determine the value of dual-phase contrast material-enhanced three-dimensional (3D) magnetic resonance (MR) angiography for preoperative evaluation of the blood supply to the liver. MATERIALS AND METHODS: Dual phase 3D MR angiography of the hepatic arteries and portal vein was performed in 140 patients. In 80 patients, the value of fat saturation, digital image subtraction, an anticholinergic agent, and a high-caloric meal were evaluated. In the next 60 patients, MR angiographic and digital subtraction angiographic (DSA) image quality and diagnostic value were compared. RESULTS: Fat-saturated images were of significantly better quality (P < .01) than non-fat-saturated images. Digital image subtraction was useful in only 23 of 40 patients. The injection of an anticholinergic agent was superfluous, whereas administration of a high-caloric meal helped in demonstration of the superior mesenteric artery and portal vein. Classification on MR angiograms of the arterial blood supply was correct in 57 of 60 patients. All arterial and portal venous lesions were seen on MR angiograms, and MR angiograms had a significantly higher subjective image-quality ranking than did DSA images in the evaluation of the portal vein (P < .05). CONCLUSION: Fat saturation and use of a high-caloric meal improve the results of MR angiography of hepatic vessels. MR angiography was comparable to DSA for evaluation of the arterial system and was superior for demonstration of the portal vein; therefore, MR angiography could replace intraarterial DSA.


Asunto(s)
Angiografía de Substracción Digital/métodos , Hígado/irrigación sanguínea , Angiografía por Resonancia Magnética/métodos , Antagonistas Colinérgicos , Medios de Contraste , Alimentos Formulados , Gadolinio DTPA , Arteria Hepática/patología , Humanos , Procesamiento de Imagen Asistido por Computador , Yohexol/análogos & derivados , Hepatopatías/diagnóstico por imagen , Hepatopatías/patología , Trasplante de Hígado , Persona de Mediana Edad , Vena Porta/patología , Estudios Prospectivos , Escopolamina
19.
Curr Opin Urol ; 9(2): 135-41, 1999 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-10726084

RESUMEN

Helical computed tomography is a new technique that acquires a volumetric data set of both kidneys within a single breath-hold. It has proved to be superior to conventional computed tomography. Multiphasic helical computed tomography after the administration of contrast material shows advantages concerning the detection and characterization of renal lesions and the preoperative staging of renal cell carcinomas. The proper scan protocol for a sufficient examination of the kidneys is described as well as its diagnostic value. The characteristic computed tomography morphology of benign and malignant renal lesions is reviewed and the advantages of helical computed tomography are illustrated.


Asunto(s)
Enfermedades Renales/diagnóstico por imagen , Tomografía Computarizada por Rayos X/métodos , Animales , Medios de Contraste/administración & dosificación , Humanos
20.
Magn Reson Imaging ; 16(8): 887-92, 1998 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-9814770

RESUMEN

We determined whether the accuracy of magnetic resonance angiography (MRA) in the peripheral run-off vessels can be improved by using contrast-enhanced (CE) three-dimensional (3D) technique in comparison to electrocardiograph (ECG)-triggered two-dimensional (2D) time-of-flight (TOF) technique. In a prospective study 20 patients with occlusions of the pelvic and/or femoral arteries underwent a CE 3D MRA (repetition time (TR): 5 ms, (TE) echo time: 2 ms, flip angle (FA): 30 degrees ) and an ECG-triggered 2D time-of-flight (TOF) technique (TR: 408 resp. 608 ms, TE: 7 ms, FA: 70 degrees) of the run-off vessels on a 1.5 T MR system. Each patient received a contrast material volume of 0.15 mmol/kg of body weight of gadolinium (Gd)/DTPA using an automatic injector. The tube system to the patient was flushed by 50 mL of a saline solution applied with the same injection rate as the contrast material administration. The start of the 3D MR sequence was tailored individually to the applied contrast material after determination of circulation times by a prior bolus. All patients underwent each conventional or digital arteriography for comparison, as well. The visualization of the run-off vessels was ranked on a scale of 0-3 (0 = poor, 1 = fair, 2 = good, 3 = excellent) by three blinded reviewers. They also graded the vascular segments as either occluded or significantly altered (>50% reduction in diameter) or free of significant stenosis. CE 3D MRA was significantly faster in imaging the run-off vessels in comparison to the ECG-triggered 2D TOF technique. All 160 vascular segments were visualized with the 3D method, whereas only 142/160 segments were seen with 2D technique. The resulting image quality ranking of all vascular segments was significantly higher (p < 0.05) using CE 3D MRA (2.8) than with the 2D TOF technique (2.4). The detection of the stenoses was possible with both techniques. The grading of seven of seven stenoses was correct with 3D method and in five of seven cases with the 2D TOF technique. All vessel occlusions were detected by using both techniques. Small collaterals were visualized in more detail with the CE 3D MR angiography. These data demonstrate an improvement in image quality and accuracy of MRA of the peripheral arteries using a CE 3D technique in comparison to an ECG-triggered 2D TOF sequence.


Asunto(s)
Electrocardiografía , Angiografía por Resonancia Magnética/métodos , Enfermedades Vasculares Periféricas/diagnóstico , Medios de Contraste , Femenino , Gadolinio DTPA , Humanos , Procesamiento de Imagen Asistido por Computador , Masculino , Estudios Prospectivos , Arterias Tibiales/patología
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