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Biomedical subjects

U Lörcher

Publications and source records attributed to U Lörcher.

18 recordsLinked to original sources
PubMed2001

Automated CT image evaluation of the lung: a morphology-based concept.

UNLABELLED: Computed tomography (CT) provides the most reliable method to detect emphysema in vivo. Commonly used methods only calculate the area of low attenuation [pixel index (PI)], while a radiologist considers the bullous morphology of emphysema. The PI is a good, well-known measure of emphysema. But it is not able to detect emphysema in cases in which emphysema and fibrosis occur at the same time. This is because fibrosis leads to a low number of low-attenuation pixels, while emphysema leads to a high number of pixels. The PI takes the average of both and, consequently, may present a result within the normal range. METHOD: The main focus of this paper is to present a new algorithm of thoracic CT image evaluation based on pulmonary morphology of emphysema. The PI is extended, in that it is enabled to differentiate between small, medium, and large bullae (continuous low-attenuation areas). It is not a texture-based algorithm. The bullae are sorted by size into four size classes: class 1 being within the typical size of lung parenchyma; classes 2-4 presenting small, medium, and large bullae. It is calculated how much area the different classes take up of all low-attenuation pixels. The bullae index (BI) is derived from the percentage of areas covered, respectively, by small, medium, and large bullae. From the relation of the area of bullae belonging to class 4, to that of those belonging to class 2, a measure of the emphysema type (ET)is calculated. It classifies the lung by the type of emphysema in bullous emphysema or small-sized, diffuse emphysema, respectively. RESULTS: The BI is as reliable as the PI. In cases in which the PI indicates normal values while in fact emphysema is coexisting with fibrosis, the BI, nevertheless, detects the destruction caused by the emphysema. The BI combined with the ET reflects the visual assessment of the radiological expert. CONCLUSION: The BI is an objective and reliable index in order to quantify emphysematous destruction, hence, avoiding interobserver variance. This is particularly interesting for follow-up. The classification of the ET is a helpful and unique approach to achieving an exact diagnosis of emphysema.

Algorithms↗
PubMed2001

[Pulmonary lymphangioleiomyomatosis--review and personal results].

Pulmonary lymphangioleiomyomatosis (LAM) is characterised by the proliferation of smooth muscle cells in the peribronchial, perivascular and perilymphatic tissue resulting in severe destructive changes of the lung parenchyma. We reviewed the literature and compared the findings in chest radiograph and CT with our own results obtained in a group of 12 patients suffering from histological proven LAM. The main findings of LAM in chest radiograph are a diffuse reticular opacity and an increased lung volume, often large cysts are visible. The CT scans reveal that cystic lesions are present in all patients, but the reported size of the cystic lesions is contradictory. We postulate two main types of LAM: the one resulting in a diffuse distribution of multiple small cysts, partially demonstrating a honey-combing pattern, the other showing severe destruction of the lung parenchyma due to large cysts. The presence of fibrotic changes and architectural distraction does not exclude LAM. So chest radiograph as well as computed tomography reveal neither uniform nor pathognomonic findings. Differential diagnosis of LAM seems to be more difficult than most authors believe.

Adult↗
PubMed1997

Spirometric gated quantitative computed tomography of the lung in healthy smokers and nonsmokers.

RATIONALE AND OBJECTIVES: The authors investigated the influence of cigarette smoking on healthy, asymptomatic smokers and nonsmokers with the help of spirometric triggered quantitative computed tomography. In our prospective study, the authors compared conventional lung function parameters with the computed tomography values (lung attenuation, lung area). METHODS: The study group comprised 40 healthy volunteers consisting of 20 smokers and nonsmokers (20 females and 20 males). The corresponding groups have been matched concerning their age, height, body mass, (cigarette) pack years. Computer tomography scans were triggered at 35%, 50%, 70% and 95% of vital capacity at a defined apical and a basal level. RESULTS: Functional residual capacity (FRC), total lung capacity and airway resistance showed close correlations to lung parenchymal attenuation values especially at full inspiration and expiration. For example, the authors found a correlation coefficient of r = -0.845 (P < or = 0.001) concerning the FRC and lung attenuation values in the apical lung at 35% of vital capacity in male smokers. Male smokers proved to have a significantly higher pulmonary lung density at all inspiratory states than the other groups (P < or = 0.05; Student's t test). Although male smokers had a higher vital capacity they showed a smaller cross-sectional area increase of the lung during inspiration than nonsmokers. This phenomenon is a result of the decreasing compliance of the smoker's lung, due to small airways disease and hypoxic vasoconstriction. CONCLUSIONS: Spirometric-triggered quantitative computed tomography has proved to be a sensitive diagnostic device for the investigation of early pathomorphologic changes in healthy, asymptomatic cigarette smokers.

Female↗
PubMed1996

Pulmonary alveolar microlithiasis in children.

Two asymptomatic Turkish sibs are presented, a 4-year-old boy and his 7-year-old sister, with pulmonary alveolar microlithiasis (PAM) confirmed by transbronchial lung biopsy and bronchoalveolar lavage. Chest radiographs and high resolution CT demonstrated widespread intra-alveolar calcifications in both lungs. The lesions were sharply defined and less than 1 mm in diameter. CT documented a high concentration of microliths along the bronchovascular bundles, the intralobular fissure and the (sub)pleural lung parenchyma. The combination of bronchoalveolar lavage and roentgenographic appearance in high resolution CT are characteristic and pathognomonic, and can confirm the diagnosis. The more severe changes in the elder sib and the radiographic controls suggest that the pulmonary disease may be progressive in our patients. The described family of consanguineous, unaffected parents with two affected and one healthy child confirmed the autosomal recessive inheritance of PAM (McKusick 265100). In addition, the affected girl had autosomal recessive Waardenburg-anophthalmia syndrome (McKusick 206920), raising the question of whether this is a chance occurrence or possibly a contiguous gene syndrome.

Biopsy↗
PubMed1993

Preliminary results of an interdisciplinary survey of drug victims.

In an interdisciplinary study, 53 cases of drug-related death were investigated. Forty per cent of these cases exhibited acute or chronic hepatitis; foreign body granulomas were detected in 30%. By CT-scan of the left lung, small abscesses and pneumonic focuses could be localized. The spectrum of bacterial strains isolated from lung tissue did not differ significantly from that of a control group. Severe alterations of the testes, i.e. reduction of spermatogenesis, was present in a considerable number of cases. The high rate of myocarditis diagnosed (18%) supports the idea that besides acute intoxication, drug-related death is due to multifactorial origin.

Acute Disease↗
PubMed1991

[Para-pleural lung lesions: diagnostic value of sonography versus computerized tomography].

UNLABELLED: 45 patients with pleural and/or peripheral lung lesions detected by chest radiography were examined by chest ultrasound. A chest CT-scan was obtained as a reference method afterwards. In 43 pleural or peripheral lung lesions we found corresponding results comparing size, invasivity and nature comparing the two diagnostic methods. In 35 of 41 cases an ultrasound (US)-guided needle biopsy confirmed the preliminary diagnosis suspected after sonography of the chest. Six needle biopsies allowed no definite diagnosis. Two patients developed a pneumothorax that required drainage after US-guided needle biopsy. CONCLUSION: Real-time sonography of the chest and chest CT-scans are complementary methods examining pleural and peripheral lung lesions, corresponding results are demonstrated in respect of location, size, invasivity and nature of the lesions.

Biopsy, Needle↗
PubMed1990

[Changes in the lungs and pleura following chemoembolization of liver tumors with mitomycin-lipiodol].

The authors performed 68 liver embolizations in 51 patients. As selectively as possible, Lipiodol, to block the capillary bed, and a chemotherapeutic agent were injected into the liver tumors. A CT performed 24 hours after treatment showed the distribution of the contrast medium which is also an indicator of the distribution of the chemotherapeutic agents. It was found that the contrast medium had accumulated not only in the liver but also in the lungs. Here, four different degrees of accumulation were found, according to the amount of Lipiodol used. Embolization of the liver thus involves potential hazards for the lungs, such as microembolisms, pneumonia, and toxic effects of the chemotherapeutic agents.

Adult↗
PubMed1989

[Combination fractures of the pelvic girdle: comparison of CT with the conventional pelvic image].

102 polytraumatised patients with pelvic fractures were studied by conventional x-rays of the pelvis as well as by computed tomography to obtain detailed information on type and degree of the fractures. We paid particular attention to acetabular and sacral fractures and combinations thereof. We found that only computed tomography enabled us to precisely define type and degree of pelvic injury. We thus draw the conclusion that each patient with proven or suspected pelvic injury should be subjected to a CT study to enable the surgeon to plan his therapy-conservative or surgical-to the best benefit of the patient.

Acetabulum↗
PubMed1989

[Appendicitis in the computed tomographic image].

29 patients with unclear symptoms in the right lower abdomen received a CT-examination in an attempt to prove or exclude appendicitis. In almost all cases it was possible to demonstrate the inflammatory process in the appendix itself (size of the organ). More diagnostic information was obtained by careful examination of the accompanying reactions of the cecum, the mesenteriolum, the fascia and other neighboring organs. Thus CT is a valuable tool in the diagnosis of appendicitis and facilitates the decision for or against an appendectomy, which otherwise may be very difficult.

Acute Disease↗
PubMed1988

[Benign segmental bronchial obstruction in computed tomography].

The benign segmental bronchial obstruction--mostly discovered on routine chest films--can well be diagnosed by CT. The specific findings in CT are the site of the bronchial obstruction, the mucocele and the localized emphysema of the involved segment. Furthermore CT allows a better approach to the underlying process.

Adolescent↗
PubMed1986

[Rounded atelectasis in the computerized tomographic image].

The rounded (helical) atelectasis is a benign alteration of the lung that can be diagnosed by radiography. Besides the criteria of the chest x-ray film and of the conventional tomogram (shadow close to the pleura, located mainly in the inferior lobe, with "comet-sign" and pleural thickening) the most important finding in computed tomography is the "octopus-sign".

Humans↗
PubMedDate not supplied

[Peutz-Jeghers syndrome--new possibilities of noninvasive diagnosis].

The ultrasonographic findings on Peutz-Jeghers syndrome are demonstrated on two cases. As a non-invasive method the digitalized computered sonography may give the opportunity to detect even small polyps. The sensitivity of this method is comparable with the MRI and gives new perspectives in the follow up of Peutz-Jeghers syndrome.

Adolescent↗
PubMedDate not supplied

[Origin and course of renal arteries. A CT study for determining optimal projection plane in renal artery angiography].

In an attempt to optimize renal artery angiography we performed a CT-study. In 500 patients we determined the angle at which the arteries arise from the aorta and their course. Both renal arteries are in one plane, which is tilted 13 degrees ventrally on the right and 13 degrees dorsally on the left. More distally we found an angle of 35 degrees on the right and an angle of 29 degrees on the left in the dorsal direction. These findings were independent of age and sex of the patient.

Adolescent↗