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R Felix

Publications and source records attributed to R Felix.

At least 55 records · Page 3Linked to original sources
PubMed2004

Whole-body hyperthermia in the scope of von Ardenne's systemic cancer multistep therapy (sCMT) combined with chemotherapy in patients with metastatic colorectal cancer: a phase I/II study.

This phase I/II study evaluated the feasibility, toxicity and response rates of von Ardenne's systemic cancer multistep therapy (sCMT) when applied as an adjunct to cytostatic therapy in patients with metastatic colorectal cancer. sCMT consists of whole-body hyperthermia (WBH) at 41.8-42.1 degrees C, hyperglycaemia and hyperoxaemia. All patients who entered the trial first received three monthly courses of chemotherapy (folinic acid, 50 mg, days 1-5; 5-fluorouracil, 425 mg/m2, days 1-5; mitomycin 8 mg/m2, day 1), followed by response evaluation according World Health Organization (WHO) criteria. Responders (partial/complete remission) were assigned to three further courses of chemotherapy, whereas non-responders (stable/progressive disease) were allocated to additional sCMT on day 1 of every subsequent chemotherapy course. The WBH procedure was administered under general anaesthesia employing the Iratherm-2000 radiant heat device. Of 28 patients enrolled, 19 received more than three treatment courses. Eight of these 19 patients had responded to chemotherapy (PR) and thus obtained three further courses of chemotherapy alone. In 10 of 19 patients who had not responded (SD, PD), three additional courses of chemotherapy were combined with sCMT (with 25 sCMT applications). One patient who did not respond to initial treatment declined sCMT and was continued with chemotherapy alone. It was found that sCMT was feasible, but associated with a specific spectrum of grade III/IV toxicity (skin 20%, pain 16%, peripheral nerves 8% of treatment courses). The fact that three patients who did not respond to initial chemotherapy achieved a PR after additional sCMT suggests that sCMT may enhance the effect of chemotherapy in patients with colorectal cancer.

Adult↗
PubMed2004

Regional pelvic hyperthermia as an adjunct to chemotherapy (oxaliplatin, folinic acid, 5-fluorouracil) in pre-irradiated patients with locally recurrent rectal cancer: a pilot study.

The aim of this study was to evaluate the feasibility and toxicity of a novel hyperthermic chemotherapy approach for patients with locally recurrent adenocarcinoma of the rectum. All patients were pre-irradiated (> or = 45 Gy) and had histologically proven pelvic recurrence. Hyperthermic chemotherapy was applied according to a modified 'OFF'-schedule with weekly infusions of 43 mg/m2 of oxaliplatin (i.v., 120 min), 500 mg/m2 of folinic acid (i.v., 120 min) and 2.6 g/m2 of continuous infusional 5-fluorouracil (24 h) for 6 consecutive weeks. Oxaliplatin was started in parallel to pelvic radiofrequency hyperthermia that was provided by the BSD 2000-system. A total of 67 applications were administered to nine patients and were well tolerated. A total of 55/67 (82%) chemotherapy courses were applied without dose-reduction. In 62/67 (93%) hyperthermia sessions, a treatment time of > 60 min was maintained. Tolerated power levels were on average 600 W and, thus, slightly lower than those described in curative pelvic hyperthermia schedules. Eight out of 10 episodes of severe (WHO III degrees) toxicity represented typical side-effects of the chemotherapy given (nausea n = 4, diarrhoea n = 3, neuropathy n = 1). Two severe adverse events were firstly attributable to hyperthermia (haematuria, n = 1; deterioration of a decubital ulcer, n = 1). No patient suffered WHO-disease progression during the treatment period. Two patients achieved a partial remission. It is concluded that hyperthermic chemotherapy with oxaliplatin, folinic acid and 5-FU is feasible on an outpatient basis. Overall toxicity was moderate, although hyperthermia may add side-effects to this approach. Results, moreover, suggest a relevant palliative effect in patients with pre-irradiated pelvic recurrence of rectal cancer.

Adenocarcinoma↗
PubMed2004

In vitro coronary artery imaging with sixteen-slice helical computed tomography.

PURPOSE: To determine the benefits of submillimeter coronary computed tomography (CT) angiography in vitro. MATERIAL AND METHODS: The coronary arteries of three domestic pigs were filled with contrast agent and depicted with clinically applicable CT angiography protocols with a slice thickness of 0.63 to 2.5 mm. RESULTS: With 2.5 mm slices, only the third-degree coronary artery branches could be discerned. With 1.25 mm slices, some fourth-degree branches of the right coronary artery could be discerned upon maximum intensity projections. With 0.63mm slices, fourth-degree coronary artery branches could be discerned in all locations. CONCLUSION: The introduction of 16-row detector CT with submillimeter z-axis resolution translates into an order-of-magnitude benefit for the depiction of coronary artery branches.

Animals↗
PubMed2004

Computed tomography-guided pulmonary nodule localization before thoracoscopic resection.

PURPOSE: To assess the success rate and complication rate of a CT-guided pulmonary nodule-marker system before thoracoscopic resection. MATERIAL AND METHODS: In 24 patients (15 M, 9 F; age range, 18-71 years) a total of 25 pulmonary nodules (in 1 patient 2 lesions simultaneously) were marked with a special wire under CT-guidance and then thoracoscopically resected. We evaluated lesion size, lesion distance to the pleura, the time of intervention, complications, and thoracoscopic success rate. RESULTS: Mean lesion size was 7 mm (range 4-15 mm) and mean lesional distance to the pleura was 13 mm (range 2-31 mm). The pulmonary nodule-marker system was positioned successfully in all 25 pulmonary nodules within 5-11 min (mean 7.5 min). Minimal pneumothoraces were observed in five patients with no requirements of chest drains. In addition, no bleeding complications or hematothorax were observed. All 25 pulmonary nodules could be resected thoracoscopically. However, in one patient (4%), the guide-wire dislocated during thoracoscopy, but the lesion could be successfully resected during thoracoscopy. CONCLUSION: The CT-guided placement of the pulmonary nodule-marker system used here offers a safe and accurate guide for the localization of small pulmonary nodules during thoracoscopic resection.

Adolescent↗
PubMed2004

Role of F18-FDG PET for monitoring of radiochemotherapy -- estimation of detectable number of tumour cells.

BACKGROUND: FDG-PET has been proven to be useful for the diagnosis of pancreatic cancer. However, no quantitative data exist concerning its sensitivity for treatment monitoring or early diagnosis. CASE REPORT: We report on a 61-year-old patient with locally advanced cancer of the pancreas head who received sequential radiochemotherapy including gemcitabine and 5-FU/FA. Under this regimen, MR and CT showed a partial remission with a residual mass which seemed to allow surgical treatment for this patient. A pre-operative FDG-PETScan displayed a count rate close to the detection limit of vital residual tumour. An R0 resection was performed successfully. However, histopathology revealed residual tumour at the core of the resected mass that had gone undetected by all imaging modalities. CONCLUSION: The number of vital tumour cells within this specimen was estimated to be 10(6)-10(7). The detection threshold for FDG-PET in pancreatic carcinoma appears to be within this range.

Cell Count↗
PubMed2004

Treatment of locally recurrent rectal cancer with special focus on regional pelvic hyperthermia.

Progress in surgery and adjuvant therapy has markedly improved local control and survival rates in patients with primary, non-metastatic rectal cancer. However, the prognosis of patients with locally recurrent disease is still poor, and a realistic chance for repeated treatment with curative intent is still restricted to the minority of cases. Therefore, effective palliation of symptoms and preservation of a good quality of life are the major goals of therapy for most patients with local recurrence of rectal cancer. Here we give a short overview on the options available for the treatment of pelvic recurrence of rectal cancer, with special focus on adjunctive regional pelvic radiofrequency hyperthermia.

Combined Modality Therapy↗
PubMed2004

Preoperative localization of parathyroid glands. Use of MRI, scintigraphy, and image fusion.

AIM: Minimally invasive resection of hyperfunctional parathyroid glands is an alternative to open surgery. However, it requires a precise preoperative localization. This study evaluated the diagnostic use of magnetic resonance (MR) imaging, parathyroid scintigraphy, and consecutive image fusion. PATIENTS, METHODS: 17 patients (9 women, 8 men; age: 29-72 years; mean: 51.2 years) with primary hyperparathyroidism were included. Examination by MRI used unenhanced T1- and T2-weighted sequences as well as contrast-enhanced T1-weighted sequences. (99m)Tc-MIBI scintigraphy consisted of planar and SPECT (single photon emission tomography) imaging techniques. In order to improve the anatomical localization of a scintigraphic focus, SPECT-data were fused with the corresponding MR-data using a modified version of the Express 5.0 software (Advanced Visual Systems, Waltham, MA). Results of image fusion were then compared to histopathology. RESULTS: In 14/17 patients, a single parathyroid adenoma was found. There were 3 cases with hyperplastic glands. MRI detected 10 (71%), scintigraphy 12 (86%) adenomas. Both modalities detected 1/3 patients with hyperplasia. Image fusion improved the anatomical assignment of the 13 scintigraphic foci in five patients and was helpful in the interpretation of inconclusive MR-findings in two patients. CONCLUSIONS: Both MRI and (99m)Tc-MIBI scintigraphy sensitively detect parathyroid adenomas but are less reliable in case of hyperplastic glands. In case of a scintigraphic focus, image fusion considerably improves its topographic assignment. Furthermore, it facilitates the evaluation of inconclusive MRI findings.

Adult↗
PubMed2003

Diagnosis of neuroendocrine tumours by retrospective image fusion: is there a benefit?

This study evaluated the use of image fusion in the preoperative staging of neuroendocrine tumors (NET) of the pancreas and the gastrointestinal tract (GIT). Thirty-eight patients suffering from a metastasized NET with location of the primary in the pancreas ( n=15) or the GIT ( n=23) were examined by somatostatin receptor scintigraphy (SRS) and computed tomography (CT). Consecutive image registration and fusion were performed using custom-built software integrated in AVS/Express (Advanced Visual Systems, Waltham, MA, USA). Registration was performed by a voxel-based algorithm based on normalized mutual information. Image fusion was feasible in 36/38 patients. A total of 87 foci were assigned to anatomical regions (e.g. gut, pancreas, liver, lymph node or others) by two independent observers in both SRS and SRS/CT fusion images. The assignments used a binary ranking system (1="definite", 0="not definite"). These results were then retrospectively compared to the classification of the foci, based on postoperative histology or clinical follow-up. Imaging by SRS allowed a definite anatomical assignment in 57% (50/87) and 61% (53/87) of all lesions in the case of observers A and B, respectively. Image fusion improved the topographic assignment to 91% (79/87) and to 93% (81/87). The number classified as "definite" by both observers increased from 54% (47/87) to 86% (77/87). The increase in definite assignments was highly significant for both observers ( P<0.0001 for each). In the case of foci classified as liver metastases, image fusion allowed improved assignment to the corresponding liver segment from 45% (18/40) to 98% (39/40) and from 58% (23/40) to 100% (40/40) by observers A and B, respectively. Furthermore, the improved assignment of foci classified as lesions by image fusion was relevant for therapy in 7/36 patients (19%). Therefore, the image fusion technique presented herein appears to be a very useful method for clinical routine.

Adult↗
PubMed2003

[Application of multislice detector spiral computed tomography to intracranial aneurysms: first clinical experience].

PURPOSE: To identify advantages when using the new multislice spiral CT technology (MSCT) for the detection and demonstration of intracranial aneurysms with CT angiography (CTA)? MATERIAL AND METHODS: Patients with suspected intracranial aneurysms underwent 4- and 8-slice spiral CTA. Image postprocessing included "maximum intensity projection" (MIP),"volume rendering" (VR) and additionally curved multiplanar reconstructions (MPR) for aneurysms suspected at the carotid siphon. The results were compared with those achieved with digital subtraction angiography (DSA). RESULTS: In 19 patients 21 out of 22 aneurysms were detected by CTA. A high resolution three-dimensional view of the aneurysm morphology in spatial relation to the surrounding structures was achieved. Further information could be gained by making a detailed examination of the inside wall of the aneurysm, using virtual vascular 3D-endoscopy and virtual 3D-craniotomy. CONCLUSION: Compared to DSA,MS-CTA is a useful additional and in selected cases alternative modality for the detection with marked advantages in the demonstration of intracranial aneurysms.

Adult↗
PubMed2003

Common herbs, essential oils, and monoterpenes potently modulate bone metabolism.

During our survey of herbs looking for activity on bone metabolism, we found that the dried leaves of sage strongly inhibit bone resorption. Therefore, we investigated several common herbs rich in essential oils (sage, rosemary, and thyme) and essential oils extracted from these herbs and other plants (oils of sage, rosemary, juniper, pine, dwarf pine, turpentine, and eucalyptus) as well as their monoterpene components (thujone, eucalyptol, camphor, borneol, thymol, alpha-pinene, beta-pinene, bornylacetate as well as menthol) and found that they inhibit bone resorption when added to the food of rats. Pine oil, used as a representative essential oil, protects an osteoporosis model, the aged ovariectomized rat, from bone loss. The monoterpenes borneol, thymol, and camphor are directly inhibitory in the osteoclast resorption pit assay. Nonpolar monoterpenes may require metabolism to be active in vitro, for example, cis-verbenol, a metabolite of alpha-pinene occurring in human urine, inhibits osteoclast activity in contrast to the parent compound. Within 30 min borneol inhibits the formation of actin rings, a characteristic of resorbing osteoclasts indicating cell polarization. Both the in vitro and the in vivo effects of borneol are reversible. Our study demonstrates for the first time that essential oils and monoterpenes are efficient inhibitors of bone resorption in the rat.

Animals↗
PubMed2003

Cryopreservation with dimethyl sulfoxide sustains partially the biological function of osteochondral tissue.

The clinical routine use of bone allograft transplants dates back to the discovery that grafts devitalized by freezing bear a reduced antigenicity. Graft failures, caused by a host versus graft reaction, however, remain a clinical problem. Previous investigations on pancreatic islet allografts revealed improved survival and biological function when fast cryopreservation (-70 degrees C/min) was performed in the presence of dimethyl sulfoxide (DMSO). The aim of this study was to determine the effect of fast freezing using DMSO on the biological function of osteochondral tissues. Organ culture was performed with neonatal femora of mice, untreated, rapidly frozen (-70 degrees C/min) with DMSO, or frozen without DMSO. After the culture, tissue morphology, cellular proliferation, osteoblast function, osteoclasts, and the presence of antigen-presenting cells were investigated. In untreated control femora histology appeared normal and proliferating and collagen-synthesizing osteoblasts, osteoclasts, and B-cells and macrophages were present. In frozen femora (with and without DMSO) a disintegration of the periosteum and the epiphyseal growth plate were observed and no active osteoblasts could be detected. Osteoclasts were partially detached from the bone surface. Cell proliferation was fully blocked in femora frozen in the absence of DMSO, while freezing in the presence of DMSO preserved cell proliferation in the medullary canal. The proliferating cells do not express epitopes present on the cells of the B-cell or macrophage lineages. Although the biological function of osteoblasts and osteoclasts was lost upon freezing of osteochondral tissue, DMSO included in freezing protocols preserves some residual cell viability which may be of importance for early graft revascularization as has been previously demonstrated by our group.

Acid Phosphatase↗
PubMed2003

[Computed tomography of the patellofemoral alignment after arthroscopic reconstruction following patella dislocation].

PURPOSE: To evaluate the diagnostic impact of different CT-based measurements to analyze the patellofemoral alignment after arthroscopic reconstruction in patients with patella dislocation. MATERIALS AND METHODS: In 18 patients with dislocation of the patella, CT of the patellofemoral joint was performed after arthroscopic reconstruction. Various methods recommended in the literature were used to analyze the structure and the alignment of the patellofemoral joint with a relaxed quadriceps muscle. Axial CT scans were taken in four different knee flexion angles (15 degrees, 30 degrees, 45 degrees, 60 degrees ). RESULTS: After arthroscopic stabilization in patients with patella dislocation, only the lateral patellofemoral angle (15 degrees and 30 degrees knee flexion) and the congruence angle (15 degrees knee flexion) showed significant differences between the CT-measurements in the normal and the operated group. The differences of the remaining mean values were not significant due to a high standard deviation. With increasing flexion of the knee, the differences between the normal and the dislocation group almost disappeared. Only the lateral patellofemoral angle, the patella tilt and the lateral patella shift revealed differences between the normal and the group with recurrent dislocation in every degree of knee flexion. With increasing knee flexion above 30 degrees and especially at 60 degrees, the majority of the measured values returned to the normal range. CONCLUSIONS: For CT-measurements of the patellofemoral joint after arthroscopic stabilization, the patellofemoral angle and the congruence angle seemed to be most useful. The measurements of the patellofemoral joint should be taken in various degrees of knee flexion.

Adolescent↗
PubMed2003

[Morphology of gastrointestinal stromal tumors in advanced stages of the disease: baseline findings before chemotherapy with imatinib].

PURPOSE: Gastrointestinal stromal tumors (GISTs) are rare tumors of the gastrointestinal tract with an increasing detection rate due to improved differentiating methods in current diagnostic pathology. This study evaluates the radiologic characteristics of these neoplasms to discover specific signs leading to an earlier diagnosis. MATERIALS AND METHODS: As part of a randomized phase III clinical trial of the European Organization for Research and Treatment of Cancer (EORTC), 72 patients with advanced stage GIST were treated with the selective tyrosine-kinase-inhibitor imatinib (Glivec, Novartis, Switzerland). For initial staging, 60 patients underwent MRI and 12 patients underwent CT. RESULTS: GISTs are mesenchymal tumors that grow submucosally and exophytically and become multiple, nodular or ovoid in the advanced stage. The predominant findings are peripheral solid structures with strong contrast enhancement and a central necrosis. Metastases are primarily located in the liver, where they appear as oval or round, sharply delineated solitary lesions with central necrosis. CT demonstrates the primary tumors and local recurrences as nearly isodense with the liver. On MRI, the lesions are hypointense on T 1 -weighted sequences and hyperintense on T 2 -weighted sequences, compared to the liver. CONCLUSION: Immunopathology now enables the exact histologic separation of GISTs from other mesenchymal tumors. The radiological morphology is not sufficiently specific to differentiate GISTs from other mesenchymal tumors. In view of new therapeutic options, cognizance of their typical manifestations is of increasing importance for radiologists.

Adult↗
PubMed2003

[MR-based volumetric analysis of small tumor volumes: accuracy of phantom examinations of simulated eye tumors].

PURPOSE: The determination of tumor volume in ocular tumors is very important for the planning and success of radiation therapy. This study uses an animal model to evaluate the accuracy of MR-based volumetry of ocular tumors. MATERIALS AND METHODS: In a total of 25 porcine eyes obtained from the slaughterhouse, ocular tumors were produced by injecting a mixture of hand creme and Gd-DTPA under ophthalmoscopic guidance. The injected volume varied between 0.05 ml and 2.7 ml. The eyes were examined with a 1.5 Tesla scanner and a 4 cm circular surface coil especially developed for ocular MRI. After data transfer to a separate workstation, volumetric analysis was carried out by three independent radiologists using semiautomated software. The determined volume was compared with the injected volume. RESULTS: Of the 25 prepared porcine eyes, 23 were suitable for volumetric analysis. The injection of the mixture of hand creme and Gd-DTPA produced two different types of tumors. Ophthalmoscopically, 14 ellipsoid and 9 lobulated to mushroom-shaped tumors were found and confirmed by MRI. Minor deviation was found between injected volume and volume calculated by MRI, with a correlation coefficient of 0.96. CONCLUSION: Using appropriate technique, MRI is capable of determining small tumor volumes with high accuracy in an animal model. Minor differences can be expected when transferring the results to clinical studies.

Animals↗
PubMed2003

[Accuracy of routine MRI in lesions of the supraspinatus tendon--comparison with surgical findings].

PURPOSE: To determine the correlation of the extent of lesions of the supraspinatus tendon in MRI's of the shoulder with surgical or arthroscopic findings using the classification of Snyders and Batemann, respectively. MATERIALS AND METHODS: The preoperative MRI's of 80 patients (age: 16 - 76/47.4 +/- 14.0 years) which were performed due to various complaints of the shoulder were analyzed retrospectively by two experienced and blinded radiologists. We evaluated the incidence and the extent of partial or complete ruptures of the supraspinatus tendon. After MRI, an arthroscopic or open surgical intervention was performed (= gold standard). Various MR-scanners were used with a field strength of 1.0 T (17 cases), or 1.5 T (63 cases) and flexible or inflexible arthro coils. Additionally to plain MRI, 38 of 80 patients underwent contrast enhanced MRI. The MR and the surgical or arthroscopic findings were compared and statistically analyzed. RESULTS: Neglecting the localization and the extent of discontinuity of the supraspinatus tendon, the sensitivity of the 80 MRI's was 0.93, the specificity 0.69, and the accuracy 0.85. The sensitivity increased to 0.96 with constant specificity and an accuracy of 0.83 excluding the lesions with an extent below 1 cm. Compared with non-enhanced examinations, the contrast enhanced MRI revealed higher sensitivity (+ 7 %, 0.89 vs. 0.96), higher specificity (+ 11 %, 0.64 vs. 0.75), and higher accuracy (+ 8 %, 0.81 vs. 0.89) in depicting lesions of the supraspinatus tendon at all. On T 1 -weighted images, the detection of lesions at all and the differentiation between partial and complete ruptures were improved significantly by contrast enhancement, especially in lesions with an extent below 1 cm. Diagnostic failures were seen in examinations without intravenous contrast application, artifacts, extent of the lesion below 1 cm, differentiating between degeneration and partial rupture of the tendon, differentiating between severely degenerated tendons with partial rupture and complete rupture, and covered ruptures. CONCLUSIONS: The performance and consecutively the analysis of the widely used MRI of the shoulder is often not sufficiently reliable in its present routine form. To be able to compete with other imaging modalities such as sonography, standardized MR protocol, contrast enhancement as needed, avoiding the described source of failure, and an exact analysis should be applied.

Adolescent↗
PubMed2003

[Evaluation of left ventricular volumes in patients with congenital heart disease and abnormal left ventricular geometry. Comparison of MRI and transthoracic 3-dimensional echocardiography].

PURPOSE: To assess the new method of 3-dimensional echocardiography in comparison to the "gold standard" MRI as to its ability to calculate left ventricular volumes in patients with congenital heart disease. MATERIALS AND METHODS: Eighteen patients between the ages of 3.9 to 37.3 years (mean: 12.8 +/- 9.7) with a geometrically abnormal left ventricle were examined using a 1.5T scanner with a fast gradient-echo sequence (TR = 14 ms, TE = 2.6 - 2.9 ms, FOV = 300 - 400 mm, flip angle = 20 degrees, matrix = 128 : 256, slice thickness = 5 mm, retrospective gating) in multislice-multiphase technique. Transthoracic 3D-echocardiography was performed with a 3.5 MHz transducer and a Tomtec (Munich, Germany) system for 3D reconstruction. RESULTS: Volume calculation was possible in all patients with 3D-echocardiography, but the muscle mass calculation only succeeded in 11 of 18 patients (61 %) due to inadequate visualization of the entire myocardium. Comparing MRI and 3D-echocardiography, the correlation was r = 0.97 for the end-systolic volumes, r = 0.98 for the end-diastolic volumes, r = 0.79 for the end-systolic muscle mass and r = 0.77 for the end-diastolic muscle mass. The agreement between both methods was considered good for the calculated end-diastolic volumes and sufficient for the calculated end-systolic volumes. The muscle mass calculations showed larger differences especially for the end-systolic mass. Mean intraobserver variability was 18.6 % for end-systolic and 8.3 % for end-diastolic volumes. CONCLUSION: In patients with an abnormal left ventricular configuration due to congenital heart disease, the new method of 3D-echocardiography is sufficient for volume calculations in preselected patients. The high intraobserver variability is still a limitation of transthoracic 3D-echocardiography in comparison to MRI.

Adolescent↗