Cerebrovascular resistance in ischemia

The cerebrovascular resistance (CVR) of rat, and its dependence on stagnant blood or endothelial capillary swelling, was studied after 10 min of total ischemia by 10 s single carotid infusion of [¹⁴C]butanol in saline. The regional saline flow (CPR) was calculated from the uptake of [¹⁴C]butanol. CVR was estimated at infusion pressures ranging from 8–25 kPa (60–190 mm Hg).At 14.7 kPa (110 mm Hg) infusion pressure, the regional CVR of the non-ischemic group varied between 0.21 and 0.40 kPa 100 g min ml^–1. After 10 min of complete global cerebral ischemia, it increased to values between 0.82 and 1.95.Removal of blood from the brain by rinsing prior to ischemia did not change the CVR in ischemia. Increasing the plasma osmolality by 8% with mannitol before ischemia attenuated the CVR increase in ischemia. Thus, although osmotic swelling of endothelial cells contributed, the main cause of the CVR increase in ischemia was constriction of arterioles.Presented in part at the Meeting of the Scandinavian Society of Physiology in Oslo, 1979     

Deep learning-based method for the continuous detection of heart rate in signals from a multi-fiber Bragg grating sensor compatible with magnetic resonance imaging

A method for the continuous detection of heart rate (HR) in signals acquired from patients using a sensor mat comprising a nine-element array of fiber Bragg gratings during routine magnetic resonance imaging (MRI) procedures is proposed. The method is based on a deep learning neural network model, which learned from signals acquired from 153 MRI patients. In addition, signals from 343 MRI patients were used for result verification. The proposed method provides automatic continuous extraction of HR with the root mean square error of 2.67 bpm, and the limits of agreement were -4.98–5.45 bpm relative to the reference HR.     

Assessment of fetal distress based on magnetic resonance examinations: preliminary report

RATIONALE AND OBJECTIVES: Hypoxia is the main cause of injuries and intrauterine death of the fetus. Therefore, the main aim of monitoring and assessment of the fetus should be diagnosis of fetal distress before irreversible changes occur. Besides the fetal condition assessment methods used so far, in recent years in obstetrics new non-invasive imaging methods were introduced such as magnetic resonance (MR). This method enables morphologic evaluation of brain and brain tissue metabolism using magnetic resonance spectroscopy (MRS). MATERIALS AND METHODS: Twenty pregnant women with pregnancy-induced hypertension (11 cases, including 3 with coexisting diabetes mellitus and 2 with intrauterine growth retardation), chronic hypertension (2 cases), gestational diabetes mellitus (6 cases), and suspected intrauterine fetal growth retardation (IUGR) participated in the study. Cardiotocography (CTG) and Doppler ultrasound examination of the blood flow in the umbilical artery and in the middle cerebral artery were performed. RESULTS: In case of abnormal CTG and Doppler study records that indicated fetal hypoxia, MR studies showed the existence of ischemic focus in 5 patients and abnormal spectral images in 6 patients. CONCLUSION: The results of the preliminary study suggests that the use of MR in prenatal diagnosis may revolutionize the early detection of fetal injury in fetal distress. It is a valuable component of the diagnostic process, supplementing other examinations. The use of MR to assess fetal condition gives additional information and helps to make decisions about therapeutic actions.     

A conservative approach to adenomas containing invasive carcinoma removed colonoscopically

A controversy exists as to the correct therapeutic approach to colorectal polyps that contain malignancy and are removed colonoscopically. This paper presents our experience in the management of such polyps. Between 1977 and 1983, a total of 117 patients underwent colonoscopic polypectomy for 178 adenomas. Nine adenomas from nine patients showed carcinomatous invasion across the line of muscularis mucosae. None of these carcinomas was poorly differentiated and in all but two cases there was histologic evidence of complete excision. Seven patients whose adenomas containing foci of malignant changes were treated by polypectomy alone are alive without recurrence at periods from six months to over five years (mean, 40 months). The two patients in whom endoscopic removal of cancerous adenomas was found to be either doubtfully complete or incomplete, had further surgical treatment; both are alive and well after one and five years, respectively. Nine other patients whose adenomas containing malignant changes were considered unsuitable for colonoscopic polypectomy, underwent surgical resection and in none was regional lymph node or distant metastases found at laparotomy. In conclusion, our results of local endoscopic excision for adenomas containing malignant changes suggest a conservative approach to such polyps and this policy is supported by the finding that, in none of our operated patients was there any evidence of metastatic disease.