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Biomedical subjects

C F Hess

Publications and source records attributed to C F Hess.

At least 55 records · Page 3Linked to original sources
PubMed1995

Abdominal wall metastasis following percutaneous endoscopic gastrostomy.

Percutaneous endoscopic gastrostomy (PEG) has become a widely used method for nutritional support, particularly in patients with advanced head and neck carcinomas. Since the method is easy and widely established it is necessary to assess possible complications, even rare ones. In this paper we report on two patients with vaccination metastasis following PEG insertion. Both patients had advanced squamous cell carcinoma of the head and neck or the upper esophagus. In three patients previous bougienage was performed, because of considerable stenosis of the pharynx and/or esophagus. Fast-growing metastases were found at the site of PEG insertion, with and without involvement of the gastric wall. In neither case was abdominal wall metastasis the cause of death. There is a small but definite risk of tumor seeding into the abdominal wall after PEG insertion for obstructive malignant tumors. The clinical impact of this finding, however, is still undefined and needs further investigation.

Abdominal Muscles↗
PubMed1995

Atypical and anaplastic meningiomas--does the new WHO-classification of brain tumours affect the indication for postoperative irradiation?

We retrospectively analysed 13 patients (pts.) treated at the University of Tübingen from 1985 to 1993 to evaluate the results of radiation therapy (XRT) given as an adjuvant to totally or subtotally resected meningiomas. The overall survival was 38% at five years with a probability of relapse of 50% at this time. Reclassification of the tumours according to the new WHO-classification of brain tumours [14] revealed 10 grade-II-tumours (atypical meningioma) and 3 grade-III-tumours (anaplastic meningioma). Radiotherapy failed in all 3 pts. with macroscopically incomplete resection (Simpson's grade IV), who died with relapse between 4 and 51 months after radiotherapy. 5 out of 10 pts. with grade-II-tumours relapsed. All 3 pts. with grade-III-tumours died with relapse between 6 and 21 months after XRT. Morbidity was seen in 2 pts. after irradiation with 60 GY (ICRU dose specification). Complete surgical exstirpation offers the best possibility of tumour control. Grade-III-tumours should be irradiated whatever the extent of the primary surgery was. Our results might indicate a possible indication for XRT in pts. with atypical grade-II-tumours especially when radical surgery must be in doubt. Prospective multicentre trials are warranted to prove the prognostic value of the new WHO-classification for atypical and anaplastic meningiomas and to define the ultimate role of radiotherapy in this setting.

Adult↗
PubMed1995

Accuracy of field alignment in radiotherapy of head and neck cancer utilizing individualized face mask immobilization: a retrospective analysis of clinical practice.

Deviations between simulation and first check films were quantitatively assessed for 95 unselected head and neck cancer patients. All measured deviations--calculated on the basis of a total of 190 simulation and 380 verification films--were normally distributed, with mean values of 0-3 mm and standard deviations of 3-5 mm. Of the absolute deviations, 50% and 95% were within 3 mm and 9 mm, respectively. These results should be considered in clinical practice when prescribing safety margins and adequate cut off doses for sparing critical organs in head and neck cancer.

Head and Neck Neoplasms↗
PubMed1994

Reproducibility of field alignment in difficult patient positioning.

PURPOSE: Quantitative assessment of the accuracy of field alignment in a homogeneous group of patients with difficult positioning (postoperative irradiation after total hip replacement). METHODS AND MATERIALS: In 95 patients linear and rotational discrepancies were measured between the simulation and first check film and between five consecutive verification films. RESULTS: For the total group of patients, all deviations were normally distributed with mean values of approximately zero and standard deviations of 4.0-8.0 mm (linear discrepancies) and 3.5-5 degrees (rotational discrepancies). Deviations were similar for the transition from simulator to the treatment machine and for subsequent treatment delivery, with 50% and 95% of absolute differences being less than 5 mm and 15 mm, respectively. CONCLUSIONS: Our analysis indicates that statistical fluctuations are considerably more important than errors introduced at start of treatment. Therefore, a first check film seems to be inadequate to predict the expected inaccuracies for the whole course of treatment. In addition, our results should help to prescribe appropriate safety margins for patients with difficult positioning.

Hip Joint↗
PubMed1994

Malignant glioma: patterns of failure following individually tailored limited volume irradiation.

Treatment outcome was analyzed for 66 patients with malignant glioma treated with individually CT-planned multifield irradiation techniques. Total doses of 60 Gy were given, with the planning target volume (PTV) including 2 cm beyond the tumour indicated by preoperative CT examination. Median survival was 14 months, and 86% of recurrences occurred in the treated volume. Our results suggest that the used PTV and radiation technique should be appropriate in radiotherapy of malignant glioma.

Astrocytoma↗
PubMed1994

Repeated CT examinations in limited volume irradiation of brain tumors: quantitative analysis of individualized (CT-based) treatment plans.

Deviations of the position of the isocenter were quantitatively assessed for CT-based limited volume irradiation of brain tumors. Of the linear deviations, 95% were within 10 mm and 3 mm during treatment planning and delivery, respectively. The application of face masks before CT planning improved the accuracy of field alignment. Repeated CT examinations seemed to be more important after simulation than during treatment delivery.

Brain Neoplasms↗
PubMed1994

How relevant is secondary leukaemia for initial treatment selection in Hodgkin's disease?

Specific tools of decision analysis, a set of mathematical rules for simplifying complex decisions, were applied to evaluate the impact of secondary leukaemia on the selection of initial treatment in Hodgkin's disease (HD). For this purpose, a combined 'expected utility' considering survival, relapse free survival, and secondary leukaemia was determined for different treatment strategies. Our analysis revealed that considerations of secondary leukaemia for initial therapy should include the a priori estimation of all possible events which may occur after initial treatment, e.g. the probabilities of recurrence and success of salvage therapy. In early and intermediate stage HD, for example, the minimal risk of leukaemia after successful radiotherapy (RT) must be weighed against the increased risk after treatment failure and subsequent salvage therapy. Thus, the difference of expected risk of leukaemia between RT and combined modality treatment (CMT) is within 4% for HD, stage II B and near to 0% in stage III A. In advanced stage HD, the addition of RT to chemotherapy has no adverse effect on the expected utility of initial treatment. These conclusions are only marginally affected by reported differences in rates of recurrence, salvage success, and secondary leukaemia. Subjective quality of life considerations, such as the latency period between treatment and leukaemia and patients' attitudes towards the occurrence of leukaemia, did not significantly affect expected utilities. In summary, our results strongly suggest that presently there is no sound basis for reducing the intensity of initial treatment in HD to avoid secondary leukaemia.

Antineoplastic Agents↗
PubMed1993

Granulocyte colony-stimulating factor treatment of leucopenia during fractionated radiotherapy.

11 patients suffering from an isolated leucopenia during fractionated radiotherapy were treated with granulocyte colony stimulating factor (G-CSF). 4 of the patients received radiotherapy alone, and 7 patients received concomitant chemotherapy. G-CSF treatment was initiated at the occurrence of leucopenia and maintained for the duration of radiotherapy. The applied daily dose was 5 micrograms/kg subcutaneously. 10 of the 11 treated patients reacted with an increased leucocyte count, from an average of 1342 leucocytes per microliter (+/- 502/microliters) to 24,568 leucocytes per microliter (+/- 950/microliters). Neutrophil counts increased on average from 64.9% (+/- 13.9%) to 91.1% (+/- 2.3%) (n = 7). In 1 patient thrombocytopenia occurred during the continued radiotherapy. 1 other patient reacted with an unexplained fall of leucocytes after two doses of G-CSF and one fraction of mediastinal irradiation. Side-effects observed during G-CSF treatment consisted of mild bone pain (1/11) and transient increases of serum alkaline phosphatase levels (4/11). Our observations indicate that G-CSF treatment is well tolerated during continuous fractionated radiotherapy. Therefore, we conclude that G-CSF can be used clinically to alleviate neutropenia caused by radiotherapy or by combined radio-chemotherapy.

Adult↗
PubMed1993

Simultaneous supra- and infradiaphragmatic irradiation in Hodgkin's disease.

From 1982 to 1989, 68 patients with Stages IA to IIIB Hodgkin's disease were treated by simultaneous supra- and infradiaphragmatic irradiation (SSI-RT). 46 patients received exclusive radiotherapy for Stages IA and IIA (extended mantle field irradiation (EMF) 31, and total lymphatic irradiation (TLI) 15). Combined modality treatment including pre-irradiation chemotherapy, was given to 22 patients (CH-EMF 12 and CH-TLI 10). The median follow-up was 64 months. 5-year overall survival was 94% in combined Stages IA and IIA, and 100% in Stage IIIA. 5-year freedom from relapse was 87% in combined Stages IA and IIA, and 80% in Stage IIIA. Toxicity was evaluated in 64 patients. Acute and long term toxicity was similar to previously reported data on sequential supra- and infradiaphragmatic irradiation. In SSI-RT prior chemotherapy affected pre-irradiation blood counts and was associated with delayed post-irradiation haematological recovery. The relative mean white blood cell (WBC) decrease ranged from 47% (EMF) to 61% (TLI). The mean platelet decrease ranged from 43% (EMF) to 80% (CH-TLI). Both prior chemotherapy and total lymphoid irradiation increased haematotoxicity. The mean duration of breaks ranged from 3.9 days in EMF to 14.9 days in CH-TLI. The mean treatment time, ranging from 43 days in EMF to 54 days in TLI, was significantly shorter than in sequential schedules (up to 112 days). Our results indicate that SSI-RT is an effective and safe treatment. Its use seems to be limited mainly by prior chemotherapy. As compared to sequential schedules, the risk of match line overlap is avoided, overall treatment time is decreased, and treatment costs are minimized.

Adolescent↗
PubMed1993

Ultrasound diagnosis of splenic lymphoma: ROC analysis of multidimensional splenic indices.

To assess the efficacy of splenic size in the sonographic diagnosis of lymphomatous involvement of the spleen, the authors studied 31 patients with splenic lymphoma (Hodgkin's disease, 17 and non-Hodgkin's lymphoma, 14) and 218 individuals without evidence of splenic disease. All subjects were studied with both a linear and a sector transducer. The longitudinal, transverse and diagonal diameters of the spleen were measured, and two- and three-dimensional splenic indices were calculated. The analysis of the diagnostic performance of these criteria, compared by means of receiver-operating characteristic (ROC) curves, revealed that diagnosis of splenic involvement by malignant lymphoma was considerably more reliable with a sector than with a linear scanner. If the longitudinal diameter was measured with a sector scanner, sensitivities were 66% and 74%, at specificities of 95% and 90% respectively (cut-off points: 12.5 cm and 11.3 cm, respectively). For the sector scanner, there was no advantage in using other diameters or multidimensional indices. Additional ROC analysis of recently published data indicating excellent discrimination capacity of a computed tomography index revealed that these results were largely owing to patient selection. In contrast, our data suggest that the potential of current non-invasive assessment of splenic lymphoma is limited. However, ultrasound may eventually help to eliminate staging laparotomy in selected cases, e.g. in patients with low risk of abdominal disease and with increased surgical risk.

Adult↗
PubMed1993

[Dosage specification at the ICRU reference point: the consequences for clinical practice. International Commission on Radiation Units and Measurements].

In the Department of Radiotherapy, University of Tübingen, dose specification is performed according to the new ICRU recommendations since June, 1991. The purpose was to prescribe, record and report photon beam therapy in a consistent way applicable to most clinical situations and to provide uniform criteria for a comparison of treatment results from different radiotherapy centers. For "level 2" plans (including CT planning), the concept of dose specification has been changed to the "ICRU reference point" instead of to form the isodose encompassing the target volume as we did previously. A total of 24 representative treatment plans have been analyzed to assess the consequences of this change on dose prescription, treatment technique, and the size of the irradiated volume. Our results revealed that the prescription of single and total doses have to be individually adjusted according to the specific treatment plans. ICRU recommendations on dose homogeneity may significantly affect treatment technique and field sizes. Small deviations in dose prescription may be of particular influence on late responding normal tissues ("double trouble" due to simultaneous adjustment of single and total doses). Detailed comparisons of individual treatment plans with respect to physical, biological, and clinical data are obviously necessary in order to make sure that the outcome of a radiation treatment is not deviating too much from the clinical experience based on the former dose specification concept.

Germany↗
PubMed1989

Diagnosis of liver cirrhosis with US: receiver-operating characteristic analysis of multidimensional caudate lobe indexes.

To assess the utility of changes in the volume of the caudate lobe in the sonographic diagnosis of liver cirrhosis, the authors studied 58 patients with histologically proved cirrhosis, 18 patients with fatty liver, 28 patients with liver metastases, seven patients with lymphomatous liver involvement, and 75 healthy individuals. The longitudinal (CL), transverse (CT), and anteroposterior (CAP) diameters of the caudate lobe and the transverse diameter of the right lobe (RL) were measured, and one-, two-, and three-dimensional caudate lobe indexes and ratios were calculated. The analysis of the diagnostic performance of these criteria, compared by means of receiver-operating characteristic curves, revealed that the ratio of the three-dimensional caudate index (CI3) to the right lobe diameter (CI3/RL = [CL X CT X CAP]/RL) was superior to all other calculated criteria. At a specificity of 95%, the sensitivity of CI3/RL was 94.7%, compared with 73.3% for CT/RL. No significant differences were found between the control group and patients with fatty liver, metastases, or lymphomatous involvement. The study suggests that CI3/RL is the most reliable quantitative criterion for the US diagnosis of liver cirrhosis.

Fatty Liver↗
PubMed1989

Diagnosis of fistulae and sinus tracts in patients with Crohn disease: value of MR imaging.

To investigate the potential of MR imaging in the evaluation of sinus tracts or fistulae associated with Crohn disease, 17 patients with pelvic or abdominal fistulae or sinus tracts underwent MR imaging with multislice spin-echo techniques, 500/15 and 1600/22,80 (TR/TE). The presence of fistulae and/or sinus tracts was confirmed by contrast-enhanced CT (n = 17) and/or sonography (n = 8), sinography (n = 6), or barium studies (n = 4). In all but three cases the fistulae and extramucosal inflammatory abnormalities were shown by MR. T1-weighted images provided excellent delineation of the extension of the fistulae relative to sphincters and adjacent hollow viscera and showed inflammatory changes in fat planes. T2-weighted images showed fluid collections within the fistulae, localized fluid collections in extraintestinal tissues, and inflammatory changes within muscles. The supralevator and infralevator compartments were well defined on coronal images. Thus, the perirectal spread of fistulae and sinus tracts with respect to the levator ani could be demonstrated in all cases. Our results suggest that MR imaging is useful for the demonstration and evaluation of pelvic and abdominal sinus tracts or fistulae associated with Crohn disease.

Abscess↗
PubMed1988

[Renal involvement in malignant lymphoma: significance of imaging technics for determining spread].

Large autopsy series show an incidence of 33 to 62% of renal involvement in all patients with malignant lymphoma; at the time of diagnosis, this is found only very rarely. The present paper describes three patients with renal involvement at the time of diagnosis. The value of sonography, CT and angiography in detecting renal involvement and its clinical significance in the management of malignant lymphoma is discussed.

Adult↗
PubMed1988

[Parameter-weighted MR images and their optimization: theory and example of images for the flash sequence compared to the spin-echo sequence].

In this paper the signal intensity and parameter-weighting zones of spin echo and gradient echo sequences (FLASH) have been analysed. Using information available in the literature, with additional analytical and numerical techniques, it is possible to determine parameters which maximise tissue contrast for T1, T2 and proton-weighted images. The technique is equally applicable to spin echo and FLASH sequences. The advantages of optimised gradient echo sequences compared with spin echo sequences with respect to its signal to noise ratio for short repetition times are analysed quantitatively. T2-weighted images can be generated as rapid as T1-weighted images, using the FLASH sequences when using a small angle of spin and relatively long echo. Illustrations are shown to demonstrate the numerical results (field strength 1.5 tesla). This is followed by a discussion of possible opposing effects.

Humans↗