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Biomedical subjects

G Doll

Publications and source records attributed to G Doll.

At least 19 recordsLinked to original sources
PubMed2000

Statistical methods for the comparison of measurements derived from orthodontic imaging.

Biometric comparison procedures for dental imaging methods with continuous outcome were reviewed, mainly concentrating on assessment and comparison of accuracy and precision according to the study design. Univariate graphical and numerical representations of corresponding deviations were summarized to derive a 'check list' of minimum information necessary to compare the measurement methods. The methods reviewed in this investigation are illustrated by the comparison of conventional (radiographic) cephalometry versus assessment using the DigiGraph in 50 female children. A paired t-test and the corresponding confidence interval approach were used to assess deviations in location of two imaging methods; the test procedures of Maloney/Rastogi, Hahn/Nelson, and Grubbs were surveyed as proposals for the comparison of precisions in paired data. The Krippendorff coefficient was used as an aggregate measure for method concordance. Since these methods can be performed by simple modification of standard options available in most statistical software packages, this review intends to enable dental researchers to choose the correct methods, and perform adequate data analysis and representation.

Algorithms↗
PubMed1993

[Reproducibility of the nyctohemeral cycle of blood pressure in patients with severe Parkinson disease].

UNLABELLED: Nineteen hospitalised, severe and treated parkinsonians (9 males, 10 females), stage IV and V of Hoehn and Yahr's classification, underwent 2 days running ambulatory blood pressure monitoring (ABPM) by ABPM 630 Nippon-Colin device, during a period of therapeutic stability. Hospitalisation allowed reproducibility of daily activity. Diurnal, nocturnal and 24 hours systolic blood pressure (SBP), as well as nocturnal and 24 hours diastolic blood pressure (DBP) were reproducible with a good correlation for each patient. Diurnal diastolic BP was the lone not reproducible value but had a good day 1-day 2 correlation. [table: see text] CONCLUSION: Parkinsonian ABPM data, except diurnal DBP, are reproducible.

Adult↗
PubMed1993

[The infiltrating angiolipoma--a rare soft tissue tumor with a malignant appearance].

Angiolipomas are rare benign soft tissue tumours that are mostly encapsulated by fibrous tissue. A case of an infiltrating angiolipoma with mixed vascularisation, not surrounded by a capsule, is described. Differentiation between lipoid degenerated fibromas, lipoid histiocytoses and haemangiomas is radiologically possible with an extensive security and enables an adequate choice of the surgical procedure.

Adult↗
PubMed1992

[A comparative study of the possibility of reducing the dosage in lateral teleradiographs].

Thanks to their capability for post-processing of image data, the digital radiological techniques introduced from 1970 onwards permit dose reduction with no loss of clinical information. The aim of this study was to establish the extent of possible dose reduction in orthodontic lateral cephalography. For this purpose, lateral cephalograms of a head phantom taken with varying radiation doses (5 to 150 mAs, constant 70 kV) were evaluated. The evaluations of ten judges were compared statistically. Conventional lateral cephalograms showed a statistically proven superiority of a number of exposure parameters for the sagittal and vertical localisation of reference points. This correlated with the radiological density of the structures. In contrast to the conventional technique, the reference points in all images obtained by digital luminescence radiography showed no such tendency. Digital luminescence thus meets the clinical need to reduce radiation dose (to about 20% of the usual dose) while providing no less diagnostic information.

Cephalometry↗
PubMed1992

[Initial experience with digital luminescence radiography in the radiological diagnosis of the visceral cranium].

The purpose of this study was the evaluation of digital luminescence radiography (PCR; Philips Computed Radiography) used in routine radiological analysis of the facial skull. Besides the standard radiographs additional PCR shots were taken in 16 cases. The subjective evaluation was carried out by three different people using clinical criteria. PCR films showed a significant advantage compared to standard radiographs for the above mentioned applications.

Evaluation Studies as Topic↗
PubMed1992

[Combined bilateral idiopathic necrosis of the humerus and femur heads: bone scintigraphy, x-ray, CT and MRT findings].

Aseptic bone necrosis in adults is usually caused by circulation defects or metabolic diseases but may also occur without any obvious reason. In these "idiopathic" cases, alcoholism seems to play a prominent role. In addition to the frequently affected femoral heads other bones may be involved. Here a remarkable pattern of localizations is reported: the bilateral idiopathic necroses of the heads of both humerus and femur. Untreated aseptic bone necroses close to a joint commonly leads to severe secondary arthrosis and destruction of the joint within a short time. Therefore, only a diagnosis in an early stage of the disease offers the chance of a successful joint-preserving therapy. In cases of clinically suspected aseptic bone necrosis but still negative or doubtful X-ray findings, bone scans or MRI are reliable methods of verifying the diagnosis.

Adult↗
PubMed1992

[The percutaneous irradiation of osteolytic bone metastases--a course assessment].

Percutaneous radiotherapy is the most effective modality for treatment of metastatic bone cancer. Local irradiation improves overall quality of life by relieving pain in most patients. It also helps preventing complications as pathological fractures in lytic bone lesions by new bone formation. In a retrospective study on 100 patients, irradiated for lytic bone metastases, the radiotherapeutic effect on alleviation of pain and on recalcification rate was investigated. In our experience in 84% of the cases pain and disability associated with bone metastases could be decreased. 38% of the patients had complete relief of symptoms. A correlation between subjective therapy effect and histology of the primary tumor was not demonstrated. Remineralization was found in 67% of all irradiated skeletal areas (n = 137) (recalcification rate in breast cancer 77%, in bronchial carcinoma 27%, and in renal cell carcinoma 25%). After a total dose of 30 Gy reduction of the metastases-associated pain was achieved in 81% of the cases and remineralization was observed in 70% of the cases.

Adult↗
PubMed1991

[Comparative study of the accuracy of localizing cephalometric reference points in using digital and conventional imaging technique].

The purpose of this study was to present possible advantages of digital luminescence radiography for cephalometry. Conventional and digitalized lateral headfilms were compared and evaluated. The first impression of an improved simultaneous presentation of bony structures and soft tissue profile in digital x-rays was statistically verified. A significant difference in identification of several reference points was proven by means of the F-test. The superior results of the digital luminescence radiography were evaluated in comparison with xeroradiography and experimental postdigitalization of conventional x-rays.

Cephalometry↗
PubMed1991

[Perceptibility of details in conventional and digital teleradiography--a comparative study].

By introduction of rare earth film-screen combinations instead of classical screens dose reduction has already been possible. By this study the extent of dose reduction without loss of clinical information was to be examined by comparing conventional radiographic rare earth film-screen combinations to digital radiography. Statistical analysis proves for conventional lateral cephalograms that soft tissue reference points can better be localized if small radiation doses are used. The localization of reference points in areas of less radiographic transparency is better when applying higher doses. These results were not found in images by digital radiographic technique. Reference points both of soft tissue and of more dense areas of the skull were equally to be localized independent from radiation dose by the linear sensibility characteristics of digital radiography. This enables reduction of radiation doses and therefore a contribution to radioprotection.

Cephalometry↗
PubMed1990

[An often ignored complication of left heart catheterization: embolism of cholesterol crystals. Report of 9 cases].

Cholesterol embolism (CE) is caused by the migration of cholesterol crystals from severe atheromatous lesions. Until recently, this was considered to be a classical but rare complication of atheroma. With the upsurge in techniques of left heart catheterization there has been a regain of interest in this subject. Nine cases of cholesterol embolism occurring after left heart catheterisation are reported, 3 after coronary angioplasty, and 3 cases after associated thrombolytic therapy. Three patients developed cutaneous syndromes (livedo reticularis, the "purple toe syndrome") with a favorable outcome in a few weeks. Two patients developed segmental necrosis of the small bowel requiring surgical resection of the affected area. Finally, in 4 cases, the patients died 12 hours to 3 months after catheterization: 2 patients had polyvisceral involvement; one patient developed cardiogenic shock; one patient had intestinal necrosis involving 2/3 of the ileum and the right colon. The cases illustrate the variability of the presentation of CE and its potential gravity. At present, the only effective measures are prophylactic; curative treatment remains particularly disappointing.

Aged↗
PubMed1990

Comparison of circadian blood pressure variations in hypertensive patients with renal artery stenosis and essential hypertension.

Ambulatory blood pressure measurements in 20 hypertensive patients with uni- or bilateral renal artery stenosis were compared with those in 20 essential hypertensive patients. Analysis of the 24 hour blood pressure curve of the renal artery stenosis group shows a tendency to equalization of blood pressure throughout the day. The nocturnal decrease of systolic or diastolic blood pressure was not significantly different between the two groups (9.2 vs. 15.3 mmHg). The blunted curve seems to be related more to the severity of hypertension than to its aetiology, but further studies are required to elucidate this point.

Adult↗
PubMed1989

[Total abnormal pulmonary venous return surgically treated in an adult].

The authors report a case of total anomalous pulmonary venous return (TAPVR) draining into the innominate (brachiocephalic) vein, discovered in a 40-year old male patient and successfully treated by surgery. This type of cardiopathy is usually suspected in the neonatal period, being badly tolerated, and such a prolonged survival is quite exceptional. Survival is conditioned by the site of the TAPVR, by the size of the atrial septal defect and also by the presence or absence of an obstacle to the pulmonary venous return and of pulmonary arterial hypertension. In the absence of pulmonary vascular disease, surgical correction is mandatory and results in regression of the symptoms and of the pulmonary arterial hypertension.

Adult↗
PubMed1989

[Arterial and venous thromboembolic complications in patients with renal transplants. Apropos of 2 cases].

The study of two cases of young patients with renal transplants who, successively and a few months after the procedure, presented a thrombophlebitis of the lower extremities (with or without pulmonary embolism), then an acute coronary insufficiency, without any encouraging or triggering factor, raises the hypothesis that this is not a mere coincidence. In fact, in the literature, numerous cardiovascular risk factors) inherent in complicated chronic renal failure, dialysis, steroid therapy and immuno-suppressive treatment (Azathioprime, under these circumstances) were demonstrated. In addition, abnormalities of the platelets aggregation, hemostasis and fibrinolysis, were at the origin of thrombo-embolic accidents. Besides any specific cardiovascular risk factor or any obvious biological anomaly, there is still a predisposition of patients with renal transplants, to arterial as well as venous thrombo-embolic accidents.

Adult↗
PubMed1988

[Value of esophageal stimulation for decreasing auricular flutter].

The purpose of this study was to evaluate the effectiveness of trans-esophageal atrial stimulation in decreasing atrial flutters. 31 patients, aged between 26 and 86 years, underwent 38 esophageal stimulations between August 1986 and April 1987. Esophageal stimulation was carried out with a device delivering major stimuli (10 to 20 ms) as well as high voltages (10 to 20 volts). A bipolar probe of permanent intracardiac stimulation was placed behind the left atrium, via a trans-esophageal approach under ECG guidance. Stimulations were carried out at a slightly faster rhythm than that of the atrial flutter, for 1 to 30 seconds with a progressive increase of the stimulation frequency (280 to 960 impulses/min) until either a sinus rhythm or an atrial fibrillation was obtained. A sinus rhythm was obtained immediately (21 times out of 38; 55.3%) and at the 24th hour after temporary atrial fibrillation in 8 additional patients (21%). The reduction percentage at 24 hours was therefore 76.3 p. cent. In 6 patients (15.8%), esophageal stimulation failed and in 3 additional patients, after atrial fibrillation, there was either relapse into flutter, or persistence of atrial fibrillation at the 24th hour. Esophageal stimulation was well tolerated in all cases. There were no local or rhythm complications. In conclusion, trans-esophageal atrial stimulation appears to be effective, easy to implement, economical and well tolerated. Its primary use to decrease atrial flutter seems justified, permitting to avoid in 75 p. cent of the time, recourse to intracardiac atrial stimulation or external shock.

Adult↗