Automatic endotracheal tube position confirmation system based on image classification--a preliminary assessment

Endotracheal intubation is a complex medical procedure in which a ventilating tube is inserted into the human trachea. Improper positioning carries potentially fatal consequences and therefore confirmation of correct positioning is mandatory. This paper introduces a novel system for endotracheal tube position confirmation. The proposed system comprises a miniature complementary metal oxide silicon sensor (CMOS) attached to the tip of a semi rigid stylet and connected to a digital signal processor (DSP) with an integrated video acquisition component. Video signals are acquired and processed by a confirmation algorithm implemented on the processor. The confirmation approach is based on video image classification, i.e., identifying desired expected anatomical structures (upper trachea and main bifurcation of the trachea) and undesired structures (esophagus). The desired and undesired images are indicators of correct or incorrect endotracheal tube positioning. The proposed methodology is comprised of a continuous and probabilistic image representation scheme using Gaussian mixture models (GMMs), estimated using a greedy algorithm. A multi-dimensional feature space, which consists of several textural-based features, is utilized to represent the images. The performance of the proposed algorithm was evaluated using two datasets: a dataset of 1600 images extracted from 10 videos recorded during intubations on dead cows, and a dataset of 358 images extracted from 8 videos recorded during intubations performed on human subjects. Each one of the video images was classified by a medical expert into one of three categories: upper tracheal intubation, correct (carina) intubation and esophageal intubation. The results, obtained using a leave-one-case-out method, show that the system correctly classified 1530 out of 1600 (95.6%) of the cow intubations images, and 351 out of the 358 human images (98.0%). Misclassification of an image of the esophagus as carina or upper-trachea, which is potentially fatal, was extremely rare (only one case when in the animal dataset and no cases when in the human intubation dataset). The classification results of the cow intubations dataset compare favorably with a state-of-the-art classification method tested on the same dataset.     

A novel design of injectable porous hydrogels with in situ pore formation

The use of injectable porous hydrogels is of great interest in biomedical applications due to their excellent permeability and ease of integration into sites of surgical intervention. By implementing a method that enables the formation in situ of pores with controllable porosity and pore size, it is possible to synthesize bioactive hydrogels that are tailor-made for specific biomedical applications. An emulsion-templating technique was used to encapsulate oil droplets, which are subsequently leached out of the hydrogel to create the porous structure. Pore size and porosity were manipulated by changing oil-to-water ratios and the surfactant concentrations. Highly swellable porous hydrogels were obtained with control over mechanical strength and diffusive properties. The relationship between porosity, pore size, and the hydrogel’s physical and mechanical characteristics was analyzed, and the potential of this material as a protein drug delivery system was demonstrated.     

Should ovarian cryopreservation be offered to girls with cancer

Current therapy of childhood cancer makes long-term survival a realistic outcome for most patients. However, some treatment regimens entail a significant risk of infertility. No established method for preservation of female fertility is currently available. Ovarian cryopreservation is an experimental technology that is being offered with increasing frequency to women undergoing cancer therapy. It has not yet been reported in children and adolescent girls. The aim of this review is to stimulate discussion on the possibility of performing ovarian cryopreservation in pre-menarcheal girls in advance of therapies that may induce ovarian failure. We present a multi-disciplinary discussion of the risks and benefits associated with the procedure and propose guidelines for its implementation. We propose that all girls about to receive treatment that has a high risk for infertility be offered consultation about the possibility of ovarian cryopreservation.     

Linear accelerator radiosurgery for meningiomas in and around the cavernous sinus

OBJECTIVE: A retrospective study to evaluate the efficacy and side effects of linear accelerator radiosurgery in the treatment of cavernous sinus meningiomas. METHODS: Between 1993 and 2001, 42 patients with meningiomas involving the cavernous sinus underwent linear accelerator radiosurgery at our institution. A mean radiation dose of 14 Gy was delivered to the tumor margin. The median tumor volume was 8.2 cm3 (mean, 8.4 cm3). Median follow-up was 36 months (mean, 38 mo). RESULTS: Control of tumor growth was achieved in 97.5% of the patients. There was no mortality or permanent extraocular motor or pituitary dysfunction. Treatment-related complications included new trigeminal neuropathy in 4.7% and a new visual field defect in 2.8%. Two patients required shunt placement after developing hydrocephalus. One patient with symptomatic temporal lobe edema underwent partial excision of the tumor. Improvement of existing cranial neuropathies was noted in 29% of affected trigeminal nerves, in 22% of oculomotor nerves, and in 13% of Cranial Nerves IV and VI. CONCLUSION: This study indicates that linear accelerator radiosurgery can achieve a high control rate of meningiomas involving the cavernous sinus with no mortality and a low incidence of morbidity.     

Mutated alleles of the rod and cone Na-Ca+K-exchanger genes in patients with retinal diseases

PURPOSE: To study the possible involvement of the rod (SLC24A1) and cone (SLC24A2) Na-Ca+K exchanger (NCKX) genes in retinal diseases. METHODS: DNA was collected from unrelated patients with retinal disease, mainly from North America. A human genomic library was screened with the cone NCKX cDNA, and hybridizing clones were sequenced to determine the genomic organization of the SLC24A2 gene. The single-strand conformation polymorphism (SSCP) technique and direct sequencing were used to screen the patients' DNA for mutations in SLC24A1 and SLC24A2. The effect of selected missense changes on protein function was tested by measuring potassium-dependent Na-Ca exchange of the mutant proteins expressed in insect cells. RESULTS: Twenty-seven novel sequence changes were found in the rod NCKX gene, 21 of which are unlikely to be pathogenic, because they did not cosegregate with the disease or did not affect conserved regions of the protein. Of the remaining six, two were frameshift mutations found in one patient each. If translated, these alleles would encode nonfunctional proteins. Three of the six possibly pathogenic mutations were missense changes located in conserved regions, and their protein functions were assayed. Only one (Ile992Thr) had a significantly low level of exchanger function, but it was found in two unrelated patients who were heterozygotes with different retinal diseases, and this mutation could not be unequivocally associated with either disease. The last of the six changes is likely to create a new splice acceptor site. The genomic organization of the cone NCKX gene was determined, and it contained 11 exons with a few splice variants. Fifteen novel sequence changes were identified in the cone exchanger gene in patients with a cone dysfunction or degeneration. Only three of these sequence changes, all missense changes found in heterozygous patients, were considered possibly pathogenic. Functional analysis showed only a slight reduction in the activity of the corresponding mutant proteins. CONCLUSIONS: Although variant alleles of the rod and cone NCKX genes were found, none could be definitively associated with a specific retinal disease. The human phenotype associated with mutant exchanger alleles remains unknown.     

Whiplash injury--a retrospective study on patients seeking compensation

The purpose of this cohort study is to evaluate the objective long-term findings and the final outcome of a population suffering from whiplash-associated disorders (WAD) after rear-end car collision and claiming legal compensation. Eight hundred and sixty-six patients after whiplash injury were followed up on average 32 months post-trauma. All patients had clinical examination and radiographs performed on the day of the accident and at follow up. MRI, CT scan, bone scan, electromyographic (EMG) tests were performed upon request of the treating physician and correlated by the authors with the clinical findings. Cervical pain was the most common complaint (96%). Radiating pain to one side of the upper limbs or the shoulder was also very common (36 and 24%, respectively). Chin to chest test was found to be a strong indicator in differentiating between the less severe (grades 1 and 2) to more severe (grades 3 and 4) WAD patients. In 10% of the patients with normal radiographic findings, degenerative changes were found at follow up. CT scan and MRI did not add to patient diagnosis, except for those patients suffering from degenerative changes and decreased range of motion (RoM). Based on our findings the initial radiograph taken in the emergency room was the best imaging modality and probably the only one needed routinely following whiplash injury. Although this is a special subgroup of patient seeking compensation, the overall prognosis is favorable in all grades of WAD injury and there is no need for further diagnostic expenditures.     

Significance of secondary ultrasonographic endometrial thickening in postmenopausal tamoxifen-treated women

BACKGROUND: Ultrasonography has a limited value in endometrial assessment for identification of endometrial pathologies in postmenopausal tamoxifen-treated patients. METHODS: We compared the rate of endometrial pathologies and the mean +/- SD of endometrial thickness diagnosed after the first and second transvaginal ultrasonographic studies performed on 55 postmenopausal tamoxifen-treated patients with secondary endometrial thickening (Group I). This rate was also compared with 46 similar patients without secondary thickening (Group II). We also compared the mean +/- SD of endometrial thickness detected in various ultrasonographic studies, as well as various clinical features. RESULTS: A significantly higher rate of endometrial pathologies, including two cases of endometrial cancer identified in gynecologically asymptomatic patients (3.6%), was diagnosed in Group I after the second study compared with the first study (52.7% and 9.1%, respectively; P = 0.001) and compared with those diagnosed after the second study in Group II (30.4%; P = 0.03). There was a significant increase (74.7 +/- 115%) in endometrial thickness after the second study compared with the first study performed on Group I (10.7 +/- 5.53 mm and 16.59 +/- 5.53 mm, respectively; P = 0.0001) and a significant difference in endometrial thickness demonstrated in the second study performed on Groups I and II (16.59 +/- 5.53 mm and 11.4 +/- 3.91 mm, respectively; P = 0.001).There were no significant differences in the time elapsed since the diagnosis of breast carcinoma and from the beginning of tamoxifen treatment to the performance of the first ultrasonographic study as well as the time elapsed between the first and second studies performed. CONCLUSIONS: A significant increase (> 50%) in secondary endometrial thickening, measured ultrasonographically, in postmenopausal tamoxifen-treated patients, is associated with a high rate of endometrial pathologies, including endometrial cancer.