Research progress on electrical impedance tomography in pulmonary perfusion / 生物医学工程学杂志

Electrical impedance tomography (EIT) is an emerging technology for real-time monitoring based on the impedance differences of different tissues and organs in the human body. It has been initially applied in clinical research as well as disease diagnosis and treatment. Lung perfusion refers to the blood flow perfusion function of lung tissue, and the occurrence and development of many diseases are closely related to lung perfusion. Therefore, real-time monitoring of lung perfusion is particularly important. The application and development of EIT further promote the monitoring of lung perfusion, and related research has made great progress. This article reviews the principles of EIT imaging, lung perfusion imaging methods, and their clinical applications in recent years, with the aim of providing assistance to clinical and scientific researchers.

Method to Identify Accessory Root Canals using a New CBCT Software

Abstract This study describes a methodology to identify accessory root canals using the e-Vol DX software in CBCT scans. Accessory root canals are strategic shelters for microorganisms present in root canal infections. The identification of these small canals in periapical radiographic exams has limitations, besides being markedly limited accessibility to the action of endodontic instruments and to the antimicrobial agents. A significant number of accessory canals have sufficient diameters to be visible on cone-beam computed tomography (CBCT) images of high spatial resolution. Therefore, it may go unnoticed or even confused when there is no specific training for this type of diagnosis. The methodology consists in establishing thin slices (0.1mm or smaller) obtained from coronal, sagittal and axial slices. The method consists of the following steps: during navigation along the long axis of a root canal when finding a possible hypodense line of main root canal in a tomographic section (axial, sagittal or coronal), the navigation software lines of the multiplanar reconstruction (MPR) must be adjusted so that they are parallel and perpendicular to the hypodense line (parallax correction). Then, after judiciously adjusted, the accessory canal image will invariably appear as a line on one of the MPR tomographic slices, another line on another slice, and a dot on the third slice. The three sections of the MPR present images with the "line-line-dot" sequence. In this way, it is possible to identify an accessory root canal and also visualize it in volumetric reconstruction in a specific filter. The application of this method is easy to employed and may benefit the diagnosis when you want to visualize accessory root canals and distinguish it from root fracture line.

Resumo Este estudo descreve um método para identificar canais radiculares acessórios usando o software e-Vol DX em imagens de TCFC. Os canais radiculares acessórios constituem abrigos estratégicos aos micro-organismos presentes nas infecções endodônticas. A identificação destes pequenos canais em exames radiográficos periapicais apresenta limitações, além de apresentar baixa acessibilidade natural a ação dos instrumentos endodônticos e dos agentes antimicrobianos. Os canais acessórios apresentam diâmetros suficientes para ficarem visíveis em imagens de tomografia computadorizada de feixe cônico (TCFC) de alta resolução espacial. Porém, podem passar despercebidos ou até confundidos quando não ocorrer treinamento específico para este tipo de diagnóstico. A metodologia consiste em estabelecer finos slices (0,1 mm ou menor) obtidos a partir de cortes coronal, sagital e axial. O método consiste nos seguintes passos: ao encontrar uma linha hipodensa de um canal radicular principal em um corte tomográfico (axial, sagital ou coronal) deve-se ajustar as linhas de navegação da reconstrução multiplanar (MPR) para que fiquem paralelas ao canal principal e perpendiculares a esta linha hipodensa (correção de paralaxe). A seguir, depois de criterioso ajuste da imagem em busca do canal acessório, aparece invariavelmente como uma linha em um dos cortes tomográficos da MPR, outra linha em outro corte e um ponto no terceiro corte. Os três cortes da MPR apresentam imagens com a sequência linha-linha-ponto. Desta maneira, pode-se identificar um canal acessório e visualizá-lo em reconstrução volumétrica em filtro específico. Esta metodologia é fácil de ser aplicada e pode beneficiar o diagnóstico quando se deseja identificar canais radiculares acessórios e distingui-lo de linha de fratura radicular.

Comparison of the Thickness of the Lamina Cribrosa and Vascular Factors in Early Normal-tension Glaucoma with Low and High Intraocular Pressures

PURPOSE: To compare the thickness of the lamina cribrosa (LC) and vascular factors of early normal-tension glaucoma (NTG) patients with high and low intraocular pressure (IOP) that are expected to be associated with the development of glaucoma. METHODS: Seventy-one Korean NTG patients with low IOP (the highest IOP 15 mmHg, 31 patients) were included in this study. The thickness of LC and vascular factors were compared. The thickness of the LC was measured using the enhanced depth imaging method with spectral domain optical coherence tomography (Heidelberg Spectralis). RESULTS: The mean thickness of the central LC was 190.0 +/- 19.2 microm in the low IOP group and 197.8 +/- 23.6 microm in the high IOP group, but there was no statistical significant difference between the two groups (p > 0.05). The prevalence of self-reported Raynaud phenomenon was significantly higher in the low IOP group (33.0%) than the high IOP group (10.3%, p = 0.04). CONCLUSIONS: The laminar thickness did not significantly differ between the high and low IOP groups. However, the prevalence of Raynaud phenomenon was higher in the low IOP groups. These results suggest that the development of glaucoma with low IOP patients may be more influenced by peripheral vasospasm, such as Raynaud phenomenon, rather than laminar thickness in NTG.

Clinical value of evaluating left ventricular mechanical synchrony by gated blood pool imaging and tissue Doppler imaging / 中国综合临床

Objective To investigate the clinical value of the gated blood pool imaging phase analysis method in the evaluation of left ventricular mechanical synchronization in patients with chronic heart failure. Methods A total of 169 patients with chronic heart failure were enrolled in our study , using gated blood pool imaging phase analysis method to obtain left ventricular phase angle width ( PHB) and left ventricular phase angle standard deviation ( PSD) as evaluating left ventricular mechanical synchrony index; using tissue Doppler imaging (TDI) measurement of the standard deviation of systolic peak time(Ts-SD) of each segment by using the current prevailing 12 non-apical segments analysis method as evaluating left ventricular mechanical synchrony index, and parameters derived from both methods were compared. Results LVPHB was highly correlated with Ts-SD (r = 0. 83 ,P = 0. 000 ) . LVPSD was modestly correlated with Ts-SD ( r - 0. 69, P = 0. 000) . The ejection fraction measured by echocardiography was (42.93 ± 14. 89) % ,which was significantly higher than that measured by ERNA (39. 76 ± 17. 89)% (P <0. 01). Conclusions The evaluation of left ventricular mechanical synchrony in patients with chronic heart failure by the gated blood pool imaging can provide similar information with TDI, which can simultaneously measure two ventricular functions and get more accurate measurement of ejection fraction. Cardiac resynchronization therapy patients can be identified by combining two kinds of approaches, and cardiac resynchronization therapy responders could be improved as well. More patients with heart failure can benefit from cardiac resynchronization therapy therapy.