A simple parametric model observer for quality assurance in computer tomography.

Model observers are mathematical classifiers that are used for the quality assessment of imaging systems such as computer tomography. The quality of the imaging system is quantified by means of the performance of a selected model observer. For binary classification tasks, the performance of the model observer is defined by the area under its ROC curve (AUC). Typically, the AUC is estimated by applying the model observer to a large set of training and test data. However, the recording of these large data sets is not always practical for routine quality assurance. In this paper we propose as an alternative a parametric model observer that is based on a simple phantom, and we provide a Bayesian estimation of its AUC. It is shown that a limited number of repeatedly recorded images (10-15) is already sufficient to obtain results suitable for the quality assessment of an imaging system. A MATLAB® function is provided for the calculation of the results. The performance of the proposed model observer is compared to that of the established channelized Hotelling observer and the nonprewhitening matched filter for simulated images as well as for images obtained from a low-contrast phantom on an x-ray tomography scanner. The results suggest that the proposed parametric model observer, along with its Bayesian treatment, can provide an efficient, practical alternative for the quality assessment of CT imaging systems.

[The state and dynamics of craniocerebral traumatism in the Kamchatka Territory].

Cranio-cerebral traumatism occupies the first place among the causes of lethal outcomes and invalidism of the population and is a serious social-economic problem. This situation requires further improvement of organization of neurotraumatic aid to the population. The work determined the regional features of the problem of cranio-cerebral traumatism in the Kamchatka Territory and proposed scientific reasons for organization of medical aid to patients with cranio-cerebral injuries.

Proposed technique for evaluation of endotracheal tube fixation and comparison of four fixation methods.

BACKGROUND: The fixation of an endotracheal tube must be rapid in conditions involving numerous casualties, such as a chemical warfare (CW) situation. The tube also should be fixed and strong to prevent unplanned extubations. METHODS: We developed a technique for the evaluation of fixation methods. This technique was used to evaluate four methods. Three commercial fixators were compared with the fixation method used today in the Israeli Defense Forces (IDF) and commonly used in different out-of-hospital settings. The exercises were performed on adult intubation mannequins with and without CW protective gear. The fixations were timed, and their quality was evaluated by the participants and inspectors. RESULTS: The time score for the method used today in the IDF was significantly higher compared with the commercial fixation methods. The quality scores for the Thomas fixator and the IDF method were significantly higher than for the fixators by VBM and Rusch. The CW protective gear significantly prolonged the time but did not affect the quality of the fixation. CONCLUSIONS: With this technique, a good estimation of the time and quality of fixation can be achieved.

[Diagnostic errors in the treatment of patients with pleural diseases]. / Vrachebnye oshibki v vedenii bol'nykh s zabolevaniiami plevry.

As illustrated by analysis of 342 case histories, none of 280 patients admitted for two years to the Center for Diagnosis and Treatment of Pleural Diseases had the verified admission diagnosis. Missed diagnosis was possible because the physicians in charge had not prescribed pleural puncture, tomography of the lungs and mediastinum after maximal removal of the exudate. Other causes were inadequate investigation of the pleural fluid, administration of antibacterial therapy and glucocorticoids in obscure diagnosis. Poor diagnosis of pleural disease reflects the absence of clear-cut policy of management of such patients as a result of which in general practice pleural diseases are detected 2 weeks after visit to a doctor, on the average. To the specialized center the patients are sent only 47 days after the disease onset. Specialists of the center make differential diagnosis with early use of needle biopsy of the pleura which enables to reduce the time of making diagnosis to 10-12 days.

[Cytological parameters of bronchoalveolar lavage in patients with chronic obstructive bronchitis exposed to laser radiation of blood]. / Tsitologicheskie pokazateli bronkhoal'veoliarnogo lavazha u bol'nykh khronicheskim obstruktivnym bronkhitom pri provedenii lazernogo oblucheniia krovi.

AIM: Clinicocytological evaluation of efficacy of combined treatment of chronic obstructive bronchitis (COB) in exacerbation with application of laser radiation of blood. MATERIALS AND METHODS: Combined treatment with the use of He-Ne intravenous and transcutaneous radiation of blood was given to 32 patients with COB. 27 COB patients treated without blood irradiation served control. Mean age of the patients (39 males and 20 females) was 59 +/- 9.5 years. In addition to conventional methods of examination and control of the treatment effect, cytological and bacteriological tests of BAL precipitate smears were made. RESULTS: Combined COB treatment with the use of laser blood radiation has an antiinflammatory action, promotes normalization of mucociliary transport, activation of phagocytosis and immune defense, cleansing of bronchial tree, reduction of obstruction (by FEV per 1 s), effective management of exacerbations. Hospital stay decreased by 3-4 days. Blood irradiation has the advantages as a noninvasive method. CONCLUSION: Clinical, cytological and bacteriological tests, determination of FEV provide a significant assessment of treatment efficacy in dynamics and facilitate the choice of the most effective regimen for management of COB in exacerbation.

[Cyclophosphane in the treatment of trophic ulcers of lower extremities with allergic and autoimmune components]. / Tsiklofosfan v lechenii troficheskikh iazv nizhnikh konechnostei s allergicheskim i autoimmunnym komponentov.

In 36 patients with varicose-trophic ulcers of the lower extremities with marked allergic and autoimmune components use of low frequency ultrasound through 0.02% solution of chlorhexidine and 0.2% cyclophosphamide made it possible to diminish allergic dermatitis and eczema after 5 or 7 procedures. The ulcers cleaned in 8-13 days (sometimes, in 14-18 days). In 27 patients surgical correction of venous blood flow was performed after the sanatation and autodermoplasty of the ulcers. There were no recurrences in the long-term period (up to 2 years).

[Treatment of purulent postoperative wounds with collagen and immobilised gentamycin]. / Lechenie gnoínykh ran kollagenom s immobilizirovannym gentamitsinom.

The results of treatment of purulent postoperative wounds in 184 patients are discussed. All the patients were operated on urgently. Various destructive diseases of the abdominal cavity organs, complicated with peritonitis, were the indication for the surgery. The abdominal cavity was drained through laparatomic wound. The wounds became suppurative with subsequent diastasis of the wound edges. Microbiologic, cytologic and clinical tests were used to estimate effectiveness of the treatment with the use of collagen sponge with immobilised gentamycin. The method has provided fastening of the healing process and shortening of in-hospital stay.

[The combined-action preparation Sipralinat in the treatment of suppurative diseases of the soft tissues and osteomyelitis of the bones of the foot]. / Preparat kombinirovannogo deistviia Sipralinat v lechenii gnoinykh zabolevanii miagkikh tkanei i osteomielita kostei stopa.

Sipralynate is a powder containing the broad spectrum antibiotic sisomicin, the enzyme protease C and the polymer carrier sodium alginate with a drainage capacity promoting wound regeneration. The clinical trials with sipralynate showed that it was highly efficient in the treatment of patients with suppurative infections of the soft tissues and ossa pedis osteomyelitis. The tolerance was good.

[Diagnosis and surgical treatment of foot osteomyelitis]. / Osobennosti diagnostiki i khirurgicheskogo lecheniia osteomyelita stopy.

The article analyses the results of surgical treatment of 227 patients with osteomyelitis of the foot bones. The peculiarities of the course of the disease, determined by the anatomical and functional features and the concomitant pathological conditions, are evaluated. Comparative appraisal of various methods of examination showed the radionuclide method to be most informative. The peculiarities of surgical operations in pyoinflammatory diseases of the foot bones, which are due to the necessary preservation of a segment of the foot for subsequent correction, call for obligatory application of combined necrectomy and a complex of agents with polyfunctional activity in addition to the traditional mechanical methods of treatment of the bone defect. The results of complex treatment were good in 72%, satisfactory in 23%, and poor in 5% of patients.

[The polymer sorbent regenkur in the treatment of suppurative wounds]. / Polimernyi sorbent regenkur v lechenii gnoinykh ran.

Clinico-laboratory tests of the new Soviet polymer sorbent Regenkur obtained on the basis of rarely cross-linked cellulose ester were conducted on 60 patients with acute purulent diseases of the soft tissues in the surgical clinic, Sechenov Medical Academy. In treatment with sorbent applications the number of microorganisms reduced by several factors on the 3rd-5th day; on the average, the term of wound cleansing was 4.6 days, granulations appeared on day 4.3 and peripheral epithelialization on day 6.5. The duration of hospital stay decreased by one third. Advantages of the new sorbent over those of the well-known foreign analogue Debrizan were revealed.

[Hemodilution coagulopathy and infusion-transfusion therapy of massive hemorrhage in obstetric practice]. / Gemodiliutsionnaia koagulopatiia i osobennosti infuzionno-transfuzionnoi terapii massivnoi krovopoteri v akusherskoi praktike.

The paper presents the experience gained by a critical hematological care team in diagnosis and treatment of hemodilution coagulopathy. The investigations were performed in Leningrad obstetric hospitals in 1985-1990 and included 38 patients. Basic principles of the therapy and its control are described. The policy of infusion-transfusion treatment indicated in the paper secured successful management of puerpera with massive blood loss.

[Detection of patients with lung cancer in a tuberculosis hospital]. / Vyiavlenie bol'nykh rakom legkogo v tuberkuleznoi bol'nitse.

For the period from 1985 to 1987 lung cancer (LC) was verified in 165 cases. High oncologic concern of the hospital doctors is explained by the fact that 92% of the patients were suspected to have LC during the first 3 days of their examination, and by the end of the 2nd week it was verified in 74.6% of them. On the average, LC diagnosis took 15.6 days. The period of LC diagnosis depends primarily on the method of producing reliable symptoms: it is minimum (7-8 days) when tumoral cells are found in sputum and exudate, and it is maximum (33 days) when diagnostic thoracotomy is done. 49.5% of the patients apply for medical care 3 to 12 months after their clinical symptoms. At the same time 67.9% of the cases examined are associated with false results that lead to their late referral to a diagnostic unit.

[Hemorrhagic complications caused by heparin therapy]. / Gemorragicheskie oslozhneniia, obuslovlennye geparinoterapiei.

The article deals with complications resulting from the application of heparin. An analysis of 92 case histories is given where hemorrhages made their appearance due to noncorrect administration of heparin. Recommendations are given for purposeful therapy of these complications and their prophylactics.

[Clinical aspects of indirect myocardial revascularization in patients with ischemic heart disease]. / Klinicheskie aspekty nepriamoi revaskuliarizatsii miokarda u bol'nykh ishemicheskoi bolezn'iu serdtsa.

The article analyses the experience in surgical treatment of patients with ischemic heart disease (504 cases) by indirect revascularization of the myocardium by creating aseptic mediastino-exo-pericarditis. Clinical characteristic of the patients is given, 81.1% of them had a history of myocardial infarction; 57.7% were invalids; the diagnosis was confirmed by coronarography in 56.2%; 92.1% of patients who underwent operation were related to III-IV functional classes. Late-5-year results showed marked improvement of the condition in 47.3%, moderate improvement in 31.6% and absence of an effect in 21.1% of patients. Postoperative lethality was 1.1%.

[Comparative evaluation of the effectiveness of biologically active and regular drainage in the prevention of disorders of wound healing]. / Sravnitel'naia otsenka éffektivnosti biologicheski aktivnogo i obychnykh drenazhei v profilaktike narusheniia zazhivleniia ran.

An analysis of clinical material on 35 patients with pyo-inflammatory processes in soft tissues is presented which were treated using biologically active drains. The cytological and cytochemical investigations have shown that draining properties of the biologically active drains are much better than those of the chlorvinyl and silicon drains.

[Effect of biologically active dressings of wounds on the course of the wound process]. / Vliianie biologicheski aktivnykh pereviazochnykh pokrytii ran na techenie ranevogo protsessa.

A comparative analysis of the effectiveness and expediency of the local application of collocyl (128 patients), trypsin immobilized on textile cellulose and kapron matrix (186 patients) and gauze bandage moistened with a solution of enzymes and 10% sodium chloride was made. It was shown that collocyl as well as trypsin modified gauze and kapron accelerated cleansing the wounds of nonviable tissues, decreased their infectivity, reduced intoxication of the organism and improved the course of the wound process.