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Biomedical subjects

W Heindel

Publications and source records attributed to W Heindel.

At least 55 records · Page 3Linked to original sources
PubMed2002

[The value of magnetic resonance imaging (MRI) for the follow-up of patients with transjugular intrahepatic portosystemic shunts (TIPS)].

PURPOSE: To prospectively determine the value of magnetic resonance imaging (MRI) with flow quantification in the portal vein for the follow-up of patients with transjugular intrahepatic portosystemic shunt (TIPS). METHODS: Thirty-six patients with TIPS (23 m, 13 f) were evaluated with MR of the liver parenchyma and quantification of flow in the portal vein. MR examinations were correlated with Doppler sonography and conventional angiography including measurement of the portal pressure gradient (PPG). In cases of re-interventions (dilatation/stent application) additional examinations with MRI and Doppler sonography were performed. RESULTS: MR flow measurements in the portal vein correlated with Doppler sonography (r = 0.69) whereas no correlation of both methods with the PPG was found. No threshold velocity in the portal vein could be determined to predict shunt stenosis. All shunt occlusions (n = 5) were diagnosed correctly by MRA. Thirty measurements before and after successful angiographic interventions revealed a significant increase in portal flow velocity and a significant decrease of the PPG. Magnetic resonance images enabled a reliable detection of procedural complications (parenchymal bleedings, n = 31; extra and subcaspular hematomas, n = 2 each) and newly occurring hepatocellular carcinomas (n = 2) in the follow-up period. CONCLUSION: Magnetic resonance imaging in the follow-up of TIPS enables a morphological assessment of the liver and an accurate velocity mapping, but is not suited to predict shunt dysfunction as a single method.

Aged↗
PubMed2002

[Selenium-based digital radiography of the cervical spine: comparison with screen-film radiography for the depiction of anatomic details].

PURPOSE: To compare selenium-based digital radiography with conventional screen-film radiography of the cervical spine. MATERIALS AND METHODS: In a prospective study X-ray images of the cervical spine were obtained in 25 patients using selenium- based digital radiography and conventional screen-film radiography. All images were clinically indicated. Selenium-based digital radiography and conventional screen-film radiography were used in a randomized order. Four radiologists independently evaluated all 50 examinations for the visibility of 76 anatomic details according to a five-level confidence scale (1 = not visible, 5 = very good visibility). From the evaluation of these anatomic details scores for the upper and middle cervical spine, the cervicothoracic junction and the cervical soft tissues were calculated. The scores for selenium-based digital radiography and conventional screen-film radiography were compared using Wilcoxon's signed rank test. RESULTS: From a total of 15,200 observations (608 per patient) the following scores were calculated for selenium-based digital radiography and for screen-film radiography, respectively: Upper cervical spine 3.88 and 3.94; middle cervical spine 4.60 and 4.48; cervico-thoracic junction 3.64 and 2.62; cervical soft tissue 4.47 and 3.46. The differences between the last two scores were statistically significant (p < 0.05). CONCLUSION: The use of selenium-based digital radiography is superior to conventional screen-film radiography in the depiction of anatomic details of the cervicothoracic junction and the cervical soft tissues.

Cervical Vertebrae↗
PubMed2002

Silicone breast implants: correlation between implant ruptures, magnetic resonance spectroscopically estimated silicone presence in the liver, antibody status and clinical symptoms.

OBJECTIVE: To determine the impact of implant integrity on clinical symptoms and antibody status in women with silicone breast implants (SBIs). METHODS: Ninety consecutive women were examined by means of magnetic resonance imaging (MRI) to assess the integrity of their silicone breast implants. The presence of silicone in the liver was estimated by (1)H localized stimulated echo acquisition mode (STEAM) magnetic resonance spectroscopy (MRS). Results were correlated with patients' complaints, as evaluated by a standardized questionnaire, physical examination by a rheumatologist and antibody screening. RESULTS: Breast MRI revealed defects in 24 patients (26.6%); in 13 (54.2%) of these women, silicone was detected in the liver by MRS. Of the 66 patients with MRI-estimated intact implants, 15 (22.7%) had apparent silicone in their liver, arguing for gel bleeding. Clinically, two patients had had rheumatoid arthritis before SBIs, whereas the other patients revealed no typical symptoms of arthritis or connective tissue disease (CTD). The patients with MRS evidence of silicone in the liver had no statistically significant differences in their complaints with the exception of the most frequent symptom, tingling/numbness of the fingers (82.1 vs 51.6%, P=0.006). A positive pattern of antinuclear antibodies (ANA) was obtained in 13 of the 28 MRS-positive patients (46.4%) and in 15 of the 62 MRS-negative patients (24.2%, P=0.033). However, in only one of these 28 ANA-positive patients was a specific weak antibody titre against SS-A detected by ELISA. CONCLUSION: Implant integrity has no major impact on rheumatic symptoms of women with SBIs. This finding supports the standpoint that silicone does not cause either a specific CTD or any other distinct disease entity. However, the moderately increased incidences of ANA-positivity and neuropathy-associated symptoms require explanation.

Adult↗
PubMed2002

[Early recognition of bronchial carcinoma with computerized tomography].

Bronchial carcinoma is the most common cause of tumor induced death worldwide. Because of the lack of clinical symptoms and signs the diagnosis of this tumor is generally established in advanced stages. With computed tomography (CT) pulmonary nodules can be detected with high sensitivity. Nodules are, because they are surrounded by aerated lung tissue, high-contrast objects and can be investigated with low-dose computed tomography technique. The reduction of mortality is the central issue in the ongoing discussion about early diagnosis of bronchial carcinoma with computed tomography. To date, no medical society or governmental body has expressed recommendations because randomized controlled trials have not been performed yet. It is expected that such trials are started in the near future in the USA and in several European countries.

Carcinoma, Bronchogenic↗
PubMed2001

Age- and sex-specific differences in the 1H-spectrum of vertebral bone marrow.

Correct interpretation of 1H magnetic resonance (MR) studies of the red vertebral bone marrow in patients with disorders of the hematopoietic system requires knowledge of the dependence of the proton spectrum on age and sex. Infiltration of malignant cells causes a decreased red bone marrow fat signal, which is reversed upon successful treatment. The aim of this study was to establish a database of normal water/fat relations from a large group of volunteers. In all, 154 healthy volunteers from 11 to 95 years of age were examined using a 1.5-T MR system (ACS-NT, Philips). A volume of 2-8 ml in the center of a normal vertebral body was selected for spectroscopy using the PRESS sequence without water suppression (TR/TE 2 sec/40 msec). Signal intensities and T2 times of lipid and water resonances were determined. The relative fat signal intensity was calculated corrected for T2 relaxation. The relative proportion of protons in the fat signal increases with age from 24% in the age group 11-20 years to 54% in the group > or = 61 years. The proportion of fat in the vertebral bone marrow in female subjects is less than that in male subjects in the same age group (statistically significant at P < or = 0.01). In the central age group between 31 and 50 years, the difference is largest, at 12%; in the youngest and oldest age group this difference is small. T2 times are neither age nor sex dependent.

Adipose Tissue↗
PubMed2001

[Bronchial carcinoma screening with low dosage CT. Current status].

Lung cancer is the most common cause of death from malignancy. It is characterized by a favourable prognosis when treated in early stages and a poor prognosis in advanced stages. Populations at risk are relatively well defined, i.e. heavy smokers and workers exposed to asbestos and radon. Therefore, early detection using diagnostic techniques promises reduction of mortality from this tumor. Previous studies using chest radiography and sputum cytology were, however, disappointing due to poor sensitivity of these tests for early tumor stages. The new technique of low-dose computed tomography provides both high sensitivity for small tumors and a comfortable examination. As small benign pulmonary nodules are common reliable non-invasive diagnostic algorithms are required for classification of nodules. Preliminary studies using low-dose CT screening in smokers have provided promising results. Prior to a wide application of the technique in clinical routine more data are required as to inclusion criteria, examination intervals and the effect of screening on mortality reduction.

Carcinoma, Bronchogenic↗
PubMed2001

Desmoplastic fibroma in the thoracic spine: an unusual localization of a rare primary bone tumor.

A case of an intraspinal growing desmoplastic fibroma of the thoracic spine (T9-T11) is reported. Desmoplastic fibroma is a rare tumor of connective tissue that shows a locally infiltrative and destructive growth. An affection of the thoracic spine is an extremely rare manifestation. Preoperative CT documents the extent of osseous destruction and tumor associated cortical erosion. In central tumor areas an inhomogeneous, intermediate to low signal is demonstrated by MRI using T1- and T2-weighted spin-echo and turbo-spin-echo sequences. Contrast-enhanced MRI shows marked enhancement in peripheral areas depicting the extraosseous and intramedullary extension.

Adolescent↗
PubMed2001

Detection of pulmonary nodules at spiral CT: comparison of maximum intensity projection sliding slabs and single-image reporting.

The aim of this study was to compare numbers of pulmonary nodules detected with maximum intensity projections using a slab thickness of 15 mm (MIP 15) and 30 mm (MIP 30) with single image (SI) presentation of chest CT scans. Two readers reviewed MIP 15, MIP 30, and SI presentations of 10-mm (n = 8) and 5-mm collimation (n = 10) helical CT scans and recorded size, location, and diagnostic confidence (definite, probable) of pulmonary nodules. Readers 1 and 2 recorded more nodules with MIP 15 than with SI: 10-mm collimation, 77/64 and 60/56; 5-mm collimation, 64/60 and 40/36; and more "definite" nodules (10-mm collimation: 68/57 and 51/42; 5-mm collimation: 43/36 and 34/30). MIP 15 also detected more nodules than MIP 30 at 10-mm collimation: 77/72 and 60/50; with no major differences at 5-mm collimation: 64/66 and 40/38; and more "definite" nodules (10-mm collimation: 68/58 and 51/36; 5-mm collimation: 43/39 and 34/29). There were only minor differences between SI and MIP 30. Reading time and image number per study were reduced with MIP presentations by a factor of 1.4-5.3. There were no significant differences in the number of nodules detected with SI, MIP 15, and MIP 30, but MIP presentation reduced reporting time and filming cost when compared with SI reporting. For detection of nodules MIP 15 was slightly superior to MIP 30.

Adolescent↗
PubMed2001

Fast sequences with fat suppression in breath-hold mode: new standard in contrast-enhanced T1-weighted MR imaging of renal tumors?

Our purpose was to analyze detection, diagnostic characterization, and staging of renal solid lesions using different fast T1-weighted sequences with fat suppression in breath-hold mode compared with a gradient-echo sequence after contrast application. Twenty-five patients with focal renal lesions were examined with a T1-weighted ultrafast turbo spin-echo (UTSE) sequence with frequency selective fat suppression (SPIR), two different segmented echo-planar imaging (EPI) sequences - a spin-echo and a gradient-echo echo-planar sequence (SE-, FFE-EPI) combined with SPIR and a gradient-echo (fast field echo, FFE) sequence in a prospective study. The images of all sequences were visually evaluated and in addition to qualitative evaluation the contrast-to-noise ratio (CNR) for cyst and solid lesions was measured. Among the different T1-weighted sequences, the best detection and characterization of renal solid lesions were obtained with the UTSE SPIR and the SE-EPI sequence (sensitivity: 100 and 75%, respectively; specificity: 90 and 75%, respectively). The FFE and FFE-EPI sequences showed lower sensitivity (86%) and the same specificity (75%). The staging of renal tumors was best achieved with the UTSE SPIR and SE-EPI sequence (84 and 73%, respectively). The staging was correct in only 47% and 58 for the FFE and FFE-EPI sequences, respectively. The investigated sequences showed no significant differences in CNR. The combination of fat suppression and breath-hold mode improves detection, characterization, and staging of renal lesions. The UTSE SPIR and SE-EPI sequence in breath-hold mode showed specific image artifacts, but offered high sensitivity and specificity for detection and characterization of renal lesions compared with the FFE sequence. The results of this study suggest, for T1-weighted imaging of renal tumors, use of UTSE or SE-EPI sequences with fat suppression in breath-hold mode for renal imaging.

Adipose Tissue↗
PubMed2001

Pulmonary manifestations of Hodgkin's disease: radiographic and CT findings.

The aim of this study was to assess the radiological and CT findings in patients with pulmonary Hodgkin's disease and to analyse to what extent CT provides more diagnostic information. In 37 patients with 41 episodes of pulmonary manifestation of Hodgkin's disease (histological diagnosis: 11, clinical diagnosis: 30) 39 radiographs and 33 CT scans were analysed by two readers in consensus. Pulmonary nodules were recorded in 77% of radiographs (CXR) and 88% of CT scans. Nodules were multiple in 67% (CXR) and 86% (CT) and bilateral in 43% (CXR) and 66% (CT) of cases, respectively. Nodule size ranged from 2 to 100 mm. Of the nodules, 83% at radiography and CT, respectively, were < or =30 mm, and again 83% at radiography and CT, respectively, were irregularly marginated. Diffuse infiltration with and without nodules was less common. With pulmonary manifestations at initial diagnosis of Hodgkin's disease there was always hilar or mediastinal lymphadenopathy. Of 20 episodes, in which radiograph and CT had been obtained within 8 days, CT demonstrated pulmonary involvement when chest radiography was normal in 3 cases and demonstrated more lesions in 12 cases. The typical appearance of pulmonary HD consisted of multiple, irregularly marginated pulmonary nodules. Diffuse infiltration was less common. Computed tomography was superior to radiography not only in characterization of lesions but could also demonstrate pulmonary involvement when the radiograph was normal and should, therefore, be used liberally in addition to radiography.

Adolescent↗
PubMed2001

Low-dose CT: new tool for screening lung cancer?

Lung cancer is the leading cause of death from malignant tumours as it is very common and has a poor prognosis at advanced tumour stages. Prognosis could be improved by treatment at early stages. As these stages are usually asymptomatic, a diagnostic test that would allow detection of early tumour stages in a population at risk could potentially reduce mortality from lung cancer. Previous approaches using chest radiography and sputum cytology in smokers have been disappointing. Fluorescent bronchoscopy and molecular markers are not yet applicable in clinical routine. Because of its high sensitivity for small pulmonary nodules, which are the most common manifestation of early lung cancer, CT appears suitable as a screening test. Low-dose examination parameters can and should be used for this purpose. From clinical practice it is well known that chest CT often demonstrates small pulmonary nodules, which do not represent lung cancer. Therefore, non-invasive diagnostic algorithms are required to avoid unnecessary biopsies in benign lesions. In preliminary studies of low-dose CT using algorithms based on size and density of detected nodules a large proportion of asymptomatic lung cancers and a large proportion of early, resectable tumour stages were found with a small proportion of invasive procedures for benign nodules. Before this technology can be recommended for broad application, however, further information is required regarding appropriate inclusion criteria (smoking habits, age groups) and screening intervals. Most importantly, further data are required to clarify whether lung cancer screening using low-dose CT can actually reduce mortality from lung cancer.

Diagnosis, Differential↗
PubMed2001

Abdominal spiral CT in children: which radiation exposure is required?

We decided to test to what extent dose reduction is possible in abdominal spiral computed tomography (CT) in young children without loss of anatomic diagnostic information. A retrospective study was performed of 30 abdominal CT examinations of children aged 3 months to 7 years. These were divided into two groups: group A with reduced radiation exposure (tube current 50 mA, CT dose index CTDIFDA < or =0.83 mGy) and group B with standard radiation exposure (tube current > or =100 mA, CTDIFDA > or =1.66 mGy). Image quality was assessed using a four-part scale ('excellent', 'good', 'sufficient', 'poor') on visual image impression and visibility of 32 anatomical details. Five experienced radiologists read the CT scans independently who were blinded to the examination parameters. Differences in ranked data were evaluated with Wilcoxon's rank sum test. No difference between groups A and B was observed in visual image impression. Detail visibility was significantly lower in group A, but the differences were limited to right upper quadrant structures (portal vein, common bile duct, pancreatic head, adrenals) and to arterial branches. Significant differences in visibility rated as 'poor' were only found for the hepatic, splenic and renal arteries; all other structures showed no difference between groups A and B. A protocol with reduced radiation exposure (50 mA, CTDIFDA < or =0.83 mGy) allowed the demonstration of most anatomic structures in abdominal spiral CT in young children. For the precise demonstration of small details (e.g. structures of the right upper quadrant), a protocol with standard radiation exposure (> or =100 mAs) was superior.

Child↗
PubMed2001

Proof of a gunshot wound and its delayed effects 54 years post injury.

In 1945 a 6-year-old girl received a tangential gunshot injury to the left posterior inferior skull. After hospitalisation because of septicemia she was unable to walk for several months. Since 1967 she had been repeatedly applying for compensation because of pseudoneurasthenia and residual ataxia and many medical examinations were performed including X-ray, CT and MRI. Although certain objective findings (e. g. cerebellar atrophy) could be verified, a causal connection between the gunshot injury and the clinical findings could not be established. Therefore previous investigators concluded on a vascular origin of the disease. During the present re-examination of the patient, the authors found patch-like scars at the left posterior inferior skull base and behind the left ear, a cord-like scar formation in the subcutaneous tissue, connecting both skin scars, a gutter-like defect in the left occipital base of the skull and an indention of the left mastoid process, both again in line between the skin scars and a large defect of the left cerebellar hemisphere. It could be concluded with certainty that the anatomical findings and the clicinal symptoms were the direct result of a gunshot injury. Previous investigations had failed because of deficient investigations and techniques. In addition to an anatomical reconstruction, three dimensional reconstructions from CT scans proved most helpful.

Ataxia↗
PubMed2001

Osteoid osteoma: CT-guided percutaneous radiofrequency ablation and follow-up in 47 patients.

PURPOSE: To evaluate computed tomography (CT)-guided radiofrequency (RF) ablation as a minimally invasive therapy for osteoid osteoma with regard to technical and clinical success and immediate and delayed complications. MATERIALS AND METHODS: Forty-seven patients (age range, 8-41 y; mean age, 19.6 y) with osteoid osteomas (femur, n = 25; tibia, n = 15; pelvis, n = 2; humerus, n = 1; ulna, n = 1; talus, n = 1; calcaneus, n = 1; vertebral body, n = 1) were treated with CT-guided RF ablation in 15 cases after one (n = 10) or two (n = 5) unsuccessful attempts at open surgical resection. Percutaneous therapy was performed with use of general or spinal anesthesia. After localization of the nidus with 1-3-mm CT sections, osseous access was established with either a 2-mm coaxial drill system or an 11-gauge Jamshidi needle. RF ablation was performed at 90 degrees C for a period of 4-5 minutes with use of a rigid RF electrode with a diameter of 1 mm. The procedures were regarded as technically successful if the tip of the RF electrode could be placed within the center of the nidus and could be heated to the desired temperature. Clinical success of treatment was defined as permanent relief of pain and return to normal function without additional treatment. In case of persistence or recurrence of symptoms after RF ablation, treatment was regarded as secondarily successful if permanent relief of symptoms could be achieved in a second procedure. RESULTS: All procedures were technically successful. Clinical success was achieved in 94% of patients (44 of 47). Three patients had recurrence of pain 3, 5, and 7 months after treatment, respectively (mean observation interval, 22 mo). All recurrences were treated successfully in a second procedure (secondary success rate, 100%). No immediate or delayed complications were observed. CONCLUSION: CT-guided percutaneous RF ablation is a simple, minimally invasive, safe and highly effective technique for treatment of osteoid osteoma.

Adolescent↗
PubMed2001

[Gd-BOPTA enhanced excretory MR urography without administration of diuretics].

PURPOSE: To evaluate the feasibility and clinical utility of Gd-BOPTA enhanced excretory magnetic resonance urography without additional administration of diuretics in correlation with conventional urography. METHOD: 15 preoperative patients with pelvic tumors were examined at 1.5 T using a breath-hold high-resolution 3D-FLASH sequence during first-pass as well as 5, 10, 15 minutes after i.v. injection of 0.05 mmol/kg BW Gd-BOPTA (MultiHance) without administration of diuretics. Post-processed coronal and multiplanar MIP reconstructions were compared to conventional excretory urography with regard to morphologic accuracy, anatomic variability, filling defects, cause and level of obstruction or compression, tumor visibility, and time-effectiveness by two independent radiologists. RESULTS: Visualization of the urinary tract by MRU was comparable to conventional excretory urography in 14 of 15 cases. Caliceal fornices were better delineated on conventional urographies, whereas MRU was considered superior in the assessment of the inferior ureter sections, the urinary bladder and obstructive tumors, whose extents could be clearly marked out. Examination times of both techniques were comparable. CONCLUSION: These first results show that non-diuretic Gd-BOPTA enhanced MRU is comparable to conventional excretory urography for the preoperative diagnosis of pelvic tumors. Further improvements of this technique seem possible by optimization of examination intervals and injection doses.

Adult↗
PubMed2001

[MRI study of left ventricular function in patients with coronary disease and myocardial dysfunction before and after coronary revascularization].

PURPOSE: To evaluate left ventricular (LV) myocardial function in ten patients with coronary artery disease (CAD) preoperatively and 6 months after coronary bypass grafting (CABG) by cardiac MRI. MATERIAL AND METHODS: Ten patients (mean 65.2 +/- 5.9 years) with angiographically proven CAD and an indication for elective CABG underwent prospective evaluation of global LV function and regional wall motion by Cine-MRI at rest using a multiphase FLASH-2D sequence following regions of interest (ROI)-defined diagnostics of regional myocardial wall motion by means of levocardiography. Within the ROIs a total of 613 LV myocardial segments were analyzed preceding and following surgical revascularization. Results were compared with the data of 10 healthy volunteers. RESULTS: Preoperatively, patients showed reduced stroke volume and ejection fraction compared with volunteers (p < 0.01). Enddiastolic wall thickness (EDWT) and systolic wall thickening (SWT) were significantly lower in the patients (p < 0.01). Based on preoperative levocardiography ROI-defined myocardial segments showed a significantly lower preoperative EDWT in areas with wall motion abnormalities (7.4 +/- 2.5 mm; p < 0.01) than in normal myocardium (9.2 +/- 2.1 mm). Ejection fraction (p < 0.05), endsystolic wall thickness, and SWT (p < 0.01) improved significantly after bypass surgery. On ROI-defined analysis myocardial segments with impaired preoperative wall motion (n = 243) showed a significant increase of EDWT, ESWT and SWT (p < 0.01). CONCLUSION: In patients with CAD, cardiac MRI enables the non-invasive determination of postinfarctional LV remodeling with an increased EDWT of myocardial segments with normal regional wall motion and of the improvement in global and regional myocardial function following coronary bypass surgery.

Aged↗
PubMed2001

[Multi-slice spiral CT of the abdomen in oncological patients: influence of table support and detector configuration on image quality and radiation exposure].

PURPOSE: To evaluate the image quality and radiation exposure of different spiral CT scanning parameters for routine staging examination of the abdomen in oncologic patients using a multi-slice CT scanner. METHODS/MATERIALS: Examination of 40 patients in 4 groups on a multi-slice CT scanner (Somatom VolumeZoom, Siemens AG, Forchheim). Functional detector width (4 x 2.5, 4 x 5 mm) and pitch (table feed in relation to collimated slice width) were varied (3 and 5). Tube voltage (120 kV), effective tube current (160 mAs), slice-thickness (6 mm), increment (4 mm), kernel (B 30), and contrast injection parameters were kept constant. Axial images were assessed by three radiologists regarding delineation of anatomic structures, artifacts, and overall image quality. RESULTS: Significantly reduced image quality especially due to artifacts was observed using a 5 mm detector configuration with a pitch of 5 (scan time 9 sec). Image quality was rated best for a 2.5 mm detector configuration with a pitch of 3 and a scan time of 28 sec. The effective dose was independent of the pitch. However, the mean effective dose was 9% higher using the smaller detector configuration (9.9 mSv vs 10.9 mSv). CONCLUSIONS: For routine staging CT of the abdomen use of a 4 x 2.5 mm detector configuration with a pitch between 3 and 5 is recommended. A 4 x 5 mm detector configuration using overlapping data acquisition can also be recommended, but additional thin slice reformations are not possible.

Abdominal Neoplasms↗