PubMed Health⌕ Search

Biomedical subjects

Mathias Langer

Publications and source records attributed to Mathias Langer.

47 records · Page 3Linked to original sources
PubMed2003

CT-guided radiofrequency heat ablation of malignant lung tumors.

BACKGROUND: Radiofrequency heat ablation (RFA) is an advanced minimal-invasive technique for the treatment of primary and secondary malignancies in several organs. This article presents the successful percutaneous computed tomography (CT)-guided radiofrequency heat ablation of a peripheral bronchiogenic carcinoma and four lung metastases in three patients. MATERIAL/METHODS: Pain relief in a palliative care situation was the indication for RFA treatment in two patients. A primary curative tumor treatment with RFA was intended in one patient, who refused surgery. All procedures were performed under conscious sedation and local anesthesia. RESULTS: RFA treatment was carried out without major complications in these patients. No signs of infection or significant bleeding were observed. One patient developed a pneumothorax two days after the procedure, which was drained sufficiently. All patients had elevated temperatures, up to 38.5 degrees C for three days after RFA, due to tumor lysis. Pain relief was possible. Control CT scans three months after percutaneous RFA revealed shrinkage of the treated tumor nodules. CONCLUSIONS: Percutaneous RFA was successfully performed in three patients. CT-guided percutaneous RFA of non-resectable lung neoplasms may be a complement to chemotherapy and radiation therapy. Further clinical experience and prospective studies are needed to determine the long-term efficacy and safety of RFA in the treatment of lung tumors.

Catheter Ablation↗
PubMed2002

Characterization of hematopoietic bone marrow in male professional cyclists by magnetic resonance imaging of the lumbar spine.

PURPOSE: To prospectively evaluate hematopoietic bone marrow of male professional cyclists in relation to performance data and laboratory data, and in comparison to age-matched healthy volunteers. MATERIALS AND METHODS: Twenty male cyclists and 44 volunteers (27 males and 17 females) were prospectively studied by magnetic resonance imaging (MRI) at high-field strength. A sagittal T1-weighted (T1-w) spin-echo (SE) sequence, a gradient-echo (GE) sequence with an echo time (TE) for out-of-phase (OOP) imaging, and a turbo inversion-recovery sequence with short inversion time (TIRM) for fat suppression was used. The averaged bone marrow signal intensity (SI) of three adjacent vertebrae was related to the signal of an adjacent nondegenerative disk. RESULTS: The cyclists revealed a significantly different SI as compared to male volunteers in the OOP (0.34 +/- 0.14 vs. 0.28 +/- 0.09, P < 0.05) and T1-w sequences (1.62 +/- 0.19 vs. 1.77 +/- 0.30, P < 0.05). Only in TIRM was there a significant difference compared to female volunteers (0.36 +/- 0.08 vs. 0.44 +/- 0.04, P < 0.01). MRI data of cyclists did not correlate to hemoglobin, erythrocyte, or reticulocyte counts; ferritin, relative heart volume, relative maximal power (rPmax; W/kg bw), or relative maximal oxygen consumption (VO(2)max). A borderline linear correlation was found for hematocrit (OOP: r = 0.42, P = 0.06; TIRM: r = 0.44, P = 0.06). CONCLUSION: Bone marrow hyperplasia is observed in male professional cyclists in the axial skeleton. The MR findings are probably independent of mechanically induced marrow edema. A multifactorial cause must be considered, as single laboratory and performance data did not appear to contribute significantly to these results.

Adult↗
PubMed2002

Pancreatico-mediastinal fistula with a mediastinal mass lesion demonstrated by MR imaging.

Internal pancreatic fistulas are uncommon but well-recognized complications of inflammatory pancreatic disease. A case of a pancreatico-mediastinal fistula with a mediastinal mass lesion in a patient with a documented history of chronic alcohol consumption and previous episodes of acute pancreatitis is described. Since the clinical symptomatology was dominated by pulmonary complaints, magnetic resonance (MR) imaging using a breathhold coronal T2-weighted sequence with spectral fat saturation was essential in clarifying this difficult and rare pathology. Furthermore, the depiction of a fistulous tract between a mediastinal mass lesion and the retroperitoneum posterior to the pancreas, i.e., a pancreatico-mediastinal fistula by MR imaging has not been previously reported, to the best of our knowledge.

Adipose Tissue↗
PubMed2002

Comparative diagnostic value and therapeutic relevance of magnetic resonance imaging and bone marrow scintigraphy in patients with metastatic solid tumors of the axial skeleton.

PURPOSE: To evaluate the comparative impact of magnetic resonance imaging (MRI) and bone marrow scintigraphy (BMS) in bone marrow metastases of solid tumors. METHODS: In 20 patients with solid tumors MRI of the axial skeleton and whole-body BMS were retrospectively reviewed. Detectability of metastases, extent of disease and therapeutic implications were assessed. RESULTS: In 15/20 (75%) patients MRI and BMS concordantly revealed bone marrow metastases of the axial skeleton. In nine of these 15 patients (60%) MRI showed more metastases. Local radiotherapy or surgery was performed in seven of these cases (78%). BMS detected additional metastases of the appendicular skeleton in 8/15 (53%) patients. In 4/20 cases (20%) the imaging findings were discordant. In three patients with degenerative changes (n=2) or lipoma (n=1) BMS was false positive. In another patient BMS failed to detect metastases proven by MRI and clinical follow-up resulting in subsequent radiation therapy. One patient had normal bone marrow. CONCLUSION: MRI appears to be more sensitive and specific in the detection of bone marrow metastases in the axial skeleton and is of clinical importance for subsequent local therapy.

Bone Marrow Neoplasms↗
PubMed2002

Combined radiofrequency thermal ablation and percutaneous cementoplasty treatment of a pathologic fracture.

Skeletal metastases commonly occur in patients with cancer and treatment is necessary to alleviate pain and prevent complications, such as mobility deficiencies and pathologic fractures. The authors present a patient with a stage IV malignant melanoma and a pathologic fracture of the left tibial plateau treated with radiofrequency heat ablation and percutaneous cementoplasty for defect filling and stabilization. The authors believe that this approach may be an alternative to the standard treatments in palliative-care situations.

Adult↗
PubMed2002

Magnetic resonance imaging for supraspinatus muscle atrophy after cuff repair.

Between 1998 to 2000, the shoulders of 17 patients with rotator cuff tears were examined using magnetic resonance imaging preoperatively, and 6 and 12 months after open surgical repair. To assess the course of the supraspinatus muscle atrophy, the easily reproducible magnetic resonance imaging parameters occupation ratio and tangent sign in the Y-shaped view of the supraspinous fossa were evaluated and compared with the clinical examination. Occupation ratio is a quantitative parameter that reflects the area ratio, expressed as a percentage of the supraspinatus muscle belly to the supraspinous fossa. The tangent sign is a qualitative parameter that represents a line connecting the coracoid process and the apex of the scapular spine. Occupation ratio and tangent sign are reliable diagnostic tools in magnetic resonance imaging assessment of supraspinatus muscle atrophy. The sensitivity of the magnetic resonance imaging parameter occupation ratio is 75% and the specificity is 85%. The imaging parameter tangent sign has a sensitivity of 100% and a specificity of 85%. There is a significant relationship between occupation ratio, tangent sign, and improvement of strength and mobility registered in the score of Constant and Murley 12 months after surgery.

Adult↗
PubMedDate not supplied

Comparison of reconstruction intervals in routine ECG-pulsed 64-row-MSCT coronary angiography in frequency controlled patients.

PURPOSE: In light of the increasing use and acceptance of multislice computed tomography (MSCT) coronary angiography it was the purpose of this study to compare reconstruction intervals used in a routine ECG-pulsed MSCT coronary artery angiography setting with frequency controlled patients. METHODS: Examinations were performed on a Siemens Somatom Sensation 64 scanner with a total of 110 ml of contrast agent and ECG pulsing (interval from 40% to 70%) after oral application of a beta-blocker if the heart rate was higher than 65 bpm. All human subjects were referred for the evaluation of suspected coronary artery disease. Coronary artery segments were evaluated by two experienced radiologists in a consensus reading. A ranking of diagnostic image quality (from 1 (no evaluation possible) to 5 (excellent image quality)) was statistically evaluated by Wilcoxon Signed Rank Test. RESULTS: In 45 patients (30 male, 15 female, age 63.8 +/- 12.1 years) we detected a significant advantage of the 60% reconstruction interval over 40%, 50%, and 70% (for each p < 0.05). In cases of sudden arrhythmia or movement during the scan, additional reconstruction intervals within the ECG-pulsed reconstruction intervals remained necessary for diagnosis. CONCLUSION: In a routine diagnostic setting with frequency controlled patients and ECG pulsing the 60% reconstruction interval can be considered superior for the initial diagnosis in 64-row multislice computed tomography coronary angiography. However, further information can be derived from various reconstruction intervals such as 40% and 70%.

Adult↗
PubMedDate not supplied

Differentiation of anal sphincters with high-resolution magnetic resonance imaging using contrast-enhanced fast low-angle shot 3-dimensional sequences.

OBJECTIVE: The imaging of the anal apparatus is becoming more and more important in the management of patients who suffer from anorectal disease. The exact differentiation of the sphincter muscles is a major requirement for the detection of disorders of the anal canal. The purpose of this study was to evaluate a new magnetic resonance (MR) imaging protocol using contrast-enhanced, high-resolution, fast low-angle shot, 3-dimensional (3D) sequences and image subtraction regarding the visualization and differentiation of the internal and external sphincter muscles. METHODS: High-resolution pelvic MR imaging (1.5 T) was performed in 85 patients (42 male, 43 female; age range: 12-81 years) with a phased-array body coil. For an anatomic overview of the pelvic region, a short tau inversion recovery sequence in the coronal plane was carried out, followed by a 3D, high-resolution, fat-saturated, T1-weighted, gradient echo sequence before and after intravenous administration of a contrast agent (gadobenic acid, 0.15 mmol/kg). To optimize the visualization of the sphincter muscles, subtraction of the unenhanced from the contrast-enhanced sequences was routinely performed. The signal intensities of the internal and external sphincter muscles were measured in the axial plane on the subtracted images. RESULTS: The distribution of the mean signal intensities of the internal and external sphincter muscles as well as the difference between both revealed a normal deviation. The confidence interval on a 95% significance level ranged between 1.6941 and 1.9393, with a mean of 1.81. In the whole study group, the signal intensity of the internal sphincter muscle was significantly higher than that of the external sphincter, thus facilitating the identification and differentiation of the 2 components of the anal sphincter complex. CONCLUSION: The presented MR imaging protocol is robust, provides a high image quality, and is well accepted by patients because of its noninvasiveness.

Adolescent↗
PubMedDate not supplied

Computed tomography coronary angiography with 370-millisecond gantry rotation time: evaluation of the best image reconstruction interval.

OBJECTIVE: To evaluate the best reconstruction window for noninvasive coronary angiography when using a 16-detector row computed tomography (CT) scanner with a gantry rotation time of 370 milliseconds. METHODS: In a pilot study, 189 coronary artery segments of 21 patients with a mean heart rate of 65 beats per minute (bpm, maximum: 45-94 bpm) were investigated using a 16-detector row CT scanner. Raw data were reconstructed in 10% increments from 40% to 70% of the RR interval. Two experienced observers independently evaluated the image quality of the coronary arteries in a segmental fashion. A 5-point ranking scale was applied, with 1 being very poor (no evaluation possible); 2, poor; 3, moderate; 4, good; and 5, very good. RESULTS: In the mean of all patients, the best reconstruction window was found to be at 60% of the RR interval. In patients with higher heart rates, the best reconstruction window was found to be at an earlier stage of the R wave-to-R wave interval. CONCLUSIONS: Initial results show that good diagnostic image quality could be achieved for all evaluated segments of the coronary tree with image reconstructions at 60% of the R wave-to-R wave interval in patients with heart rates of 70 bpm or less. Using a 16-detector row CT scanner with a gantry rotation time of 370 milliseconds, the need for adapting the reconstruction window to each segment for the best image quality was overcome in those cases. In patients with heart rates faster than 70 bpm, reconstructions at an earlier stage within the cardiac cycle were necessary.

Adult↗
PubMedDate not supplied

Sinonasal computed tomography in patients with Wegener's granulomatosis.

The goal of this study was to describe pathologies of sinonasal CT in patients with Wegener's granulomatosis. Between 1993 and 2004, sinonasal CT was performed in 28 patients (15 male, 13 female) with Wegener's granulomatosis. The following imaging findings were assessed on the CT scans: mucosal thickening, subtotal opacification, air-fluid level, bony destruction, sclerosing osteitis, bony thickening, orbital mass, and saddle nose deformity. Of the 28 patients, 61% showed mucosal thickening in the nasal cavity and 75% in the paranasal sinuses. A subtotal opacification of the paranasal sinuses was detected in 25%, and of the mastoid cells in 7% of patients. Fifty-seven percent of patients had bony destruction of the nasal cavity, and 54% of the paranasal sinuses. CT revealed sclerosing osteitis of the paranasal sinuses in 21%, and of the mastoid cells in 18% of patients. Bony thickening of the paranasal sinuses was detected in 18%, and of the mastoid cells in 14% of patients. With respect to all imaging findings, the maxillary sinuses were the most frequently affected paranasal sinuses. The authors conclude that the following sinonasal CT findings are observed in patients with Wegener's granulomatosis: (1) bony destruction, mainly of the nasal cavity, maxillary sinuses, and mastoid cells; (2) sclerosing osteitis, mainly of the maxillary sinuses and mastoid cells; (3) bony thickening, mainly of the maxillary sinuses and mastoid cells; and (4) mucosal thickening, mainly of the maxillary sinuses. These findings are, however, nonspecific and should be combined with other clinicopathologic and laboratory studies to confirm the diagnosis of Wegener's granulomatosis.

Adult↗