Research progress on protective effect of hydrogen molecule and its products on lung transplantation / 器官移植

Ischemia-reperfusion injury after lung transplantation is the main cause of primary graft dysfunction, which will subsequently reduce the function of lung allograft and lower the overall survival rate of lung transplant recipients. As a physiological regulatory molecule, hydrogen molecule has the functions of anti-inflammation, easing oxidative stress, alleviating direct cell injury and mitigating epithelial edema. Recent studies have demonstrated that hydrogen molecule and its products (hydrogen and hydrogen-rich solution) could significantly mitigate ischemia-reperfusion injury and postoperative complications after lung transplantation. In this article, the protective effect and exact mechanism of hydrogen molecule and its products in lung transplantation were reviewed, aiming to provide theoretical basis for the application of hydrogen molecule and its products as a novel treatment for lung transplantation-related complications, enhance the overall prognosis and improve the quality of life of lung transplant recipients

Preservation and functional maintenance of lung allograft / 器官移植

As the final resolution for end-stage lung disease, lung transplantation can not only significantly prolong the survival, but also remarkably improve the quality of life of recipients. In recent decades, with the advancement of surgical techniques, immunosuppressants and post-transplantation management, the quantity of lung transplantation has been surged around the globe. However, the shortage of donor lung has severely restricted the development of lung transplantation. It is necessary to develop innovative approaches to expand the donor pool. The number of donors and effective preservation and functional maintenance of potential donor lungs play a key role in expanding the donor pool. The quality of donor lung is a critical precondition to ensure the long-term survival of lung transplant recipients. Preservation and functional maintenance of donor lung are of significance for guaranteeing the quality of lung allograft. In this article, research progresses on the management and maintenance of donor lung before procurement, the procurement of donor lung and the preservation and functional maintenance of lung allograft were reviewed, aiming to provide reference for the development of lung transplantation in clinical practice.

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.

Pulmonary perfusion defect index, pulmonary artery obstruction index and right heart function parameters for evaluating the severity of pulmonary embolism / 中国基层医药

Objective:To investigate the value of pulmonary perfusion defect index (PPDI), pulmonary artery obstruction index (PAOI) and right heart function parameters in the evaluation of severity of pulmonary embolism.Methods:The clinical data of 108 patients with pulmonary embolism who received treatment in The Second Hospital of Jiaxing from January 2019 to June 2021 were retrospectively analyzed. These patients were divided into high-risk ( n = 25), moderate-risk ( n = 32), and low-risk ( n = 51) groups according to the severity of pulmonary embolism. PAOI, PPDI, right ventricular short axis maximum diameter (RV), left ventricular short axis maximum diameter (LV), ratio of right/left right ventricular short axis maximum diameter (RV/LV) were determined in each group. PPDI, PAOI and right ventricular function parameters were correlated with the severity of pulmonary embolism. The area under the receiver operating characteristic curve, specificity and severity of PPDI, PAOI, RV, LV, RV/LV used alone and in combination to predict the severity of pulmonary embolism were analyzed. Results:PPDI, PAOI, RV, and RV/LV in the high-risk group were (32.52 ± 10.85)%, (45.01 ± 15.02)%, (50.32 ± 12.32) mm, (1.42 ± 0.45), respectively, which were significantly lower than (5.32 ± 1.85)%, (12.52 ± 3.25)%, (37.25 ± 8.52) mm, (0.96 ± 0.21) in the low-risk group, and LV was significantly lower in the high-risk group than that in the low-risk group [(35.14 ± 10.52) mm vs. (44.02 ± 15.21) mm, t = 13.95, 11.91, 2.62, 6.09, 5.44, all P < 0.05]. PPDI, PAOI, RV, and RV/LV in the moderate-risk group were (18.62 ± 6.02)%, (28.65 ± 8.65)%, (45.85 ± 10.02) mm, and (1.20 ± 0.32), respectively, which were significantly higher than those in the low-risk group ( t = 14.75, 12.06, 4.18, 4.13, all P < 0.05). There was no significant difference in LV between moderate-risk and low-risk groups ( t = 1.51, P > 0.05). Spearman correlation analysis showed that PPDI, PAOI, RV, RV/LV were positively correlated with the severity of pulmonary embolism ( r = 0.87, 0.84, 0.45, 0.41, all P < 0.001). LV was negatively correlated with the severity of pulmonary embolism ( r = -0.27, P < 0.001). The receiver operating characteristic curve (ROC curve) showed that the areas under the receiver operating characteristic curve of PPDI, PAOI, RV, LV, RV/LV used alone or in combination to predict the severity of pulmonary embolism were 0.941, 0.911, 0.721, 0.693, 0.726, and 0.951, respectively (all P < 0.001). Conclusion:PPDI, PAOI and right heart function parameters can be used as effective indexes to dynamically monitor the severity of pulmonary embolism.

Metabolomic fingerprinting of porcine lung tissue during pre-clinical prolonged ex vivo lung perfusion using in vivo SPME coupled with LC-HRMS / 药物分析学报

Normothermic ex vivo lung perfusion(NEVLP)has emerged as a modernized organ preservation tech-nique that allows for detailed assessment of donor lung function prior to transplantation.The main goal of this study was to identify potential biomarkers of lung function and/or injury during a prolonged(19 h)NEVLP procedure using in vivo solid-phase microextraction(SPME)technology followed by liquid chromatography-high resolution mass spectrometry(LC-HRMS).The use of minimally invasive in vivo SPME fibers for repeated sampling of biological tissue permits the monitoring and evaluation of biochemical changes and alterations in the metabolomic profile of the lung.These in vivo SPME fibers were directly introduced into the lung and were also used to extract metabolites(on-site SPME)from fresh perfusate samples collected alongside lung samplings.A subsequent goal of the study was to assess the feasibility of SPME as an in vivo method in metabolomics studies,in comparison to the traditional in-lab metabolomics workflow.Several upregulated biochemical pathways involved in pro-and anti-inflammatory responses,as well as lipid metabolism,were observed during extended lung perfusion,especially between the 11th and 12th hours of the procedure,in both lung and perfusate samples.However,several unstable and/or short-lived metabolites,such as neuroprostanes,have been extracted from lung tissue in vivo using SPME fibers.On-site monitoring of the metabolomic profiles of both lung tissues through in vivo SPME and perfusate samples on site throughout the prolonged NEVLP procedure can be effectively performed using in vivo SPME technology.

Current status and prospect of global development of lung transplantation / 器官移植

During the novel coronavirus pneumonia (COVID-19) pandemic from 2020 to 2021, lung transplantation entered a new stage of development worldwide. Globally, more than 70 000 cases of lung transplantation have been reported to the International Society for Heart and Lung Transplantation (ISHLT). With the development of medical techniques over time, the characteristics of lung transplant donors and recipients and the indications of pediatric lung transplantation recipients have undergone significant changes. Application of lung transplantation in the treatment of COVID-19-related acute respiratory distress syndrome (ARDS) has also captivated worldwide attention. Along with persistent development of lung transplantation, it will be integrated with more novel techniques to make breakthroughs in the fields of artificial lung and xenotransplantation. In this article, research progresses on the characteristics of lung transplant donors and recipients around the world were reviewed and the development trend was predicted, enabling patients with end-stage lung disease to obtain more benefits from the development of lung transplantation technique.

Clinical research progress on pediatric lung transplantation / 器官移植

Lung transplantation is an efficacious treatment for end-stage lung diseases in children. Shortage of donor lungs, poor donor-recipient matching, difficult postoperative management, multiple postoperative complications and high fatality jointly restrict the development of pediatric lung transplantation. However, significant progress has been achieved in each transplantation center along with the popularization of organ donation after citizen' s death, advancement of medical science and technology and accumulation of lung transplantation experience. In recent years, clinical application of donor lung from donation after brain death and marginal donor lung repair, maturity of perioperative life support technology and surgical transplantation procedure and reference of management experience after adult lung transplantation have accelerated rapid development of pediatric lung transplantation. In this article, current status and progress on primary diseases, utilization and allocation of donor lungs, selection of surgical techniques, management of postoperative complications and clinical prognosis of pediatric lung transplantation were elucidated, aiming to provide reference for clinical diagnosis and treatment.

Research progress on risk factors of primary graft dysfunction after lung transplantation / 器官移植

Lung transplantation is the only effective approach to treat end-stage lung diseases. Nevertheless, early prognosis of lung transplant recipients is significantly worse than that of other solid organ transplant recipients. Primary graft dysfunction (PGD) is one of the main causes affecting clinical prognosis of the recipients. PGD is an early acute lung injury after lung transplantation, which is the main cause of early death of lung transplant recipients. Risk factors of PGD after lung transplantation consist of donor, recipient and operation, etc. In this article, the risk factors of PGD after lung transplantation were reviewed, aiming to provide reference for clinical practice.

Development and prospect of clinical research on lung transplantation in post-COVID-19 era / 器官移植

Lung transplantation has been advanced for nearly half a century around the globe, and it has been developed rapidly for over 20 years in China. The field of lung transplantation in China has been gradually integrated into the international community. The outbreak of novel coronavirus pneumonia (COVID-19) in 2020 brought big challenges, as well as diverted the worldwide attention to the development of lung transplantation in China, accelerating international communication and cooperation. With the steadily deepening of clinical and basic research on lung transplantation for severe cases of COVID-19, organ transplant physicians have deepened the understanding and thinking of the maintenance of donors, selection of elderly and pediatric candidates, and perioperative management of recipients, as the future perspective of lung transplantation in China. For interdisciplinary research related to lung transplantation, it is necessary to carry out multi-center clinical trials with qualified study design and constantly promote the theoretic and practical innovation.

Experimental study on the role of IL-10 in improving donor lung function after ex vivo lung perfusion in rats of cardiac death / 器官移植

Objective To evaluate the effect of interleukin (IL)-10 on donor lung function after ex vivo lung perfusion (EVLP) in rats of cardiac death. Methods Twenty adult male SD rats were randomly divided into the simple perfusion group (group A, n=10) and modified perfusion group (group B, n=10). Perfusate A (without IL-10) and perfusate B (supplemented with IL-10) was administered in group A and B, respectively. The EVLP rat models of cardiac death were established. The appearance of donor lung, dry-to-wet (D/W) ratio of donor lung tissues, the function and metabolism of donor lung, the morphology of donor lung and the levels of inflammatory markers of donor lung were statistically compared between two groups. Results After perfusion, evident edema of the whole donor lung, poor compliance and a large amount of edema fluid discharged from the airway were observed in group A, whereas no obvious edema and good compliance were found in group B. Compared with group A, the D/W ratio of lung tissues in group B was higher (P < 0.05). In both groups, the pulmonary vein partial pressure of oxygen reached the peak at 2 h after perfusion, which did not significantly differ between two groups (P > 0.05). In group B, the pulmonary artery pressure was increased at a lower speed and significantly lower after perfusion, and the lactic acid level in the perfusate was significantly lower than those in group A (all P < 0.05). In group A, the alveolar structure was largely destroyed and the cells was rare. In group B, the alveolar structure was relatively normal without evident cell edema. The incidence of cell apoptosis of donor lung was high in group A, whereas no obvious cell apoptosis of donor lung was noted in group B. After perfusion for 4 h, the levels of monocyte chemoattractant protein (MCP)-1 and IL-6 were significantly increased, the IL-4 levels were remarkably decreased (all P < 0.05), but the levels of tumor necrosis factor (TNF)-α, IL-1α and inducible nitric oxide synthase (iNOS) did not significantly change in both groups (all P > 0.05). Conclusions IL-10 may improve the function of donor lung after EVLP in rat of cardiac death by reducing cell apoptosis.

Comparative Analysis of Lung Perfusion Scan and SPECT/CT for the Evaluation of Functional Lung Capacity / 대한핵의학회잡지

PURPOSE: This study aimed to compare lung perfusion scan with single photon emission computed tomography/computed tomography (SPECT/CT) for the evaluation of lung function and to elucidate the most appropriate modality for the prediction of postoperative lung function in patients with lung cancer.METHODS: A total of 181 patients underwent Tc-99m macroaggregated albumin lung perfusion scan and SPECT/CT to examine the ratio of diseased lung and diseased lobe. Forty-one patients with lung cancer underwent both preoperative and postoperative pulmonary function tests within 1 month to predict postoperative pulmonary function. Predicted postoperative forced expiratory volume in 1 s (ppoFEV₁) was calculated by the % radioactivity of lung perfusion scan and SPECT, and the % volume of the residual lung, assessed on CT.RESULTS: The ratios of diseased lung as seen on lung perfusion scan and SPECT showed significant correlation, but neither modality correlated with CT. The ratios of the diseased lung and diseased lobe based on CT were higher than the ratios based on either perfusion scan or SPECT, because CT overestimated the function of the diseased area. The lobar ratio of both upper lobes was lower based on the perfusion scan than on SPECT but was higher for both lower lobes. Actual postoperative FEV₁ showed significant correlation with ppoFEV₁ based on lung perfusion SPECT and perfusion scan.CONCLUSIONS: We suggest SPECT/CT as the primary modality of choice for the assessment of the ratio of diseased lung area. Both perfusion scan and SPECT/CT can be used for the prediction of postoperative lung function.

Comparison of ex vivo lung perfusion with cold storage in rat donor lung preservation / 上海交通大学学报（医学版）

Objective: To establish stable rat ex vivo lung perfusion (EVLP) model and compare the effect of preservation between EVLP group and cold storage group. Methods: Eight SD rats were reconditioned with EVLP for 4 h and 8 SD rats were under 3-h cold storage and 1-h EVLP. The biological index, wet-to-dry weight ratio and concentration of Evans blue were analyzed between two groups. Results: Wet-to-dry weight ratio of lung tissue in EVLP group was significantly lower (5.08±0.88 vs 6.09±0.48, P=0.012); Oxygenation index in EVLP group was significantly higher [(337.9±35.5) mmHg vs (300.5±21.6) mmHg, P=0.023]; Concentration of Evans blue in EVLP group was significantly lower [(36.5±20.3) μg/mL vs (65.0±29.9) μg/mL, P=0.043]. Conclusion: EVLP as an alternative to traditional cold storage technique can effectively alleviate the lung damage.

Comparison of ex vivo lung perfusion with cold storage in rat donor lung preservation / 上海交通大学学报（医学版）

Objective·To establish stable rat ex vivo lung perfusion (EVLP) model and compare the effect of preservation between EVLP group and cold storage group.Methods· Eight SD rats were reconditioned with EVLP for 4 h and 8 SD rats were under 3-h cold storage and 1-h EVLP.The biological index,wet-to-dry weight ratio and concentration of Evans blue were analyzed between two groups.Results · Wet-to-dry weight ratio of lung tissue in EVLP group was significantly lower (5.08±0.88 vs 6.09±0.48,P=0.012);Oxygenation index in EVLP group was significantly higher [(337.9±35.5) mmHg vs (300.5±21.6) mmHg,P=0.023];Concentration of Evans blue in EVLP group was significantly lower [(36.5±20.3) μg/mL vs (65.0±29.9) μg/mL,P=0.043].Conclusion · EVLP as an alternative to traditional cold storage technique can effectively alleviate the lung damage.

Training and evaluation of donor lung procurement technique in swine models / 器官移植

Objective To investigate the training methods and evaluation parameters for donor lung procurement technique in swine models. Methods The surgical skills of donor lung procurement in 15 swine models were summarized. The operation time, objective evaluation parameters before lung perfusion, gross observation after lung perfusion, the type and frequency of intraoperative errors were assessed. Results All donor lung procurement surgeries were successfully completed in 15 swine models. The mean time interval from skin incision to lung perfusion was 22.6 min. Prior to lung perfusion, the oxygenation index of the donor lung was (501±68) mmHg, (404±100) mL (under the pressure of 15 mmHg) for the tidal volume and (29±4) mL/cmH2O for the static compliance. Along with the increasing surgical frequency, the oxygenation index and tidal volume were improved. Favorable lung inflation was obtained after lung perfusion in a majority of swine models. Intraoperatively, multiple operating errors occurred including dissection error, pulmonary arterial intubation error and procedure error, etc. As the frequency of operation increased, the frequency of surgical errors was significantly decreased. Conclusions After certain training for donor lung procurement in swine models, the incidence of intraoperative procedure error is significantly reduced and the quality of the donor lung tends to be enhanced. Objective parameters, such as oxygenation index and the gross shape of the donor lung can be utilized to evaluate the levels of surgical techniques.

Effect of aerosolized iloprost inhalation on pulmonary arterial pressure and hypoxic pulmonary vasocon-striction during one-lung ventilation / 临床麻醉学杂志

Objective To investigate the effect of aerosol inhalation of iloprost on pulmonary arterial pressure and hypoxic pulmonary vasoconstriction (HPV)during one-lung ventilation (OLV) in rats.Methods Thirty male rats were randomly divided into three groups,10 in each group. Models of lung perfusion were established,100% FiO 2 was ensured under the condition of OLV and the atomizers were opened.Atomization inhalation with normal saline was performed in group A,ilo-prost at a concentration of 0.05 μg·kg-1 ·min-1 in group B and iloprost at a concentration of 0.1μg·kg-1 ·min-1 in group C.Mean pulmonary artery pressure (MPAP)and PaO 2 of drainage-fluid from left atrium were recorded at time points of perfusion for 10 min (T1 ),aerosol inhalation for 10 min (T2 )and OLV for 1 h (T3 ).Oxygenation index (OI)was calculated with PaO 2 at each time point.Both lungs were harvested for electronic microscope detection.Results MPAPs at T2 and T3 were higher in contrast with that at T1 (P <0.05).A decrease of MPAP at T2 and T3 showed in group B and C when compared with those in group A (P <0.05).Group C had lower MPAP in comparison with group B at each time point.Considering the time span,we found that OIs at T2 and T3 were lower than that at T1 .In addition,OIs at T2 and T3 in group C were higher than those in group B,respectively.Under elec-tronic microscope,nuclear membranes typeⅡ alveolar epithelial cells of both lungs in group A and of non-ventilated lungs in group B and C bulged out or invaginated and lamellar bodies were evacuated,especially when compared to those in ventilated lungs in groups B and C.Conclusion In rat models of lung perfusion, atomization inhalation with iloprost can decreased MPAP,reduce intrapulmonary shunt and increase oxygen-ation.

Estudio de la perfusión pulmonar posterior al cierre percutáneo del conducto arterioso permeable utilizando el dispositivo Amplatzer Duct Occluder en niños / Lung perfusion studies after percutaneous closure of patent ductus arteriosus using the Amplatzer Duct Occluder in children

Objetivo: La reducción en la perfusión pulmonar se ha descrito tras el cierre percutáneo del conducto arterioso permeable con varios dispositivos. Evaluamos la perfusión pulmonar posterior al cierre percutáneo del conducto arterioso con el dispositivo Amplatzer Duct Occluder utilizando la gammagrafía pulmonar de perfusión. Métodos: Treinta pacientes con oclusión transcatéter exitosa del conducto arterioso permeable utilizando el dispositivo Amplatzer Duct Occluder fueron incluidos en este estudio. La gammagrafía pulmonar de perfusión se realizó 6 meses después del procedimiento. Las velocidades de flujo máximo y la protrusión del dispositivo fueron analizadas por ecocardiografía Doppler. Una perfusión pulmonar izquierda < 40% se consideró anormal. Resultados: El implante del dispositivo fue exitoso en todos. La media de perfusión hacia el pulmón izquierdo fue de 44.7 ± 4.9% (37.8-61.4). Cinco pacientes (16.6%) mostraron disminución en la perfusión pulmonar izquierda. Tanto la edad y el peso bajo, así como la longitud del conducto arterioso y la relación diámetro mínimo y máximo con la longitud del conducto arterioso fueron estadísticamente significativos en los pacientes con anomalías de la perfusión pulmonar. Se observó protrusión del dispositivo en 6 pacientes con una velocidad de flujo máximo mayor en la arteria pulmonar izquierda. Conclusión: La perfusión pulmonar izquierda puede comprometerse tras el cierre percutáneo del conducto arterioso con el Amplatzer Duct Occluder. El aumento en la velocidad de flujo en el origen de la arteria pulmonar izquierda puede ser un pobre indicador de la reducción en la perfusión pulmonar y puede ocurrir en ausencia de protrusión del dispositivo.

Objective: The closure of patent ductus arteriosus with multiple devices has been associated with a reduction in lung perfusion. We evaluated the pulmonary perfusion after percutaneous closure of patent ductus arteriosus with the Amplatzer Duct Occluder device using perfusion lung scan. Methods: Thirty patients underwent successful percutaneous patent ductus arteriosus occlusions using the Amplatzer Duct Occluder device were included in this study. Lung perfusion scans were preformed 6 months after the procedure. Peak flow velocities and protrusion of the device were analyzed by Doppler echocardiography. A left lung perfusion < 40% was considered abnormal. Results: The device implantation was successful in all patients. Average perfusion of left lung was 44.7 ± 4.9% (37.8-61.4). Five patients (16.6%) showed decreased perfusion of the left lung. Age, low weight, the length of the ductus arteriosus and the minimum and maximum diameter/length of the ductus arteriosus ratio were statistically significant in patients with abnormalities of lung perfusion. It was observed protrusion the device in 6 patients with a higher maximum flow rate in the left pulmonary artery. Conclusion: The left lung perfusion may be compromised after percutaneous closure of patent ductus arteriosus with the Amplatzer Duct Occluder. The increased flow velocity in the origin of the left pulmonary artery can be a poor indicator of reduction in pulmonary perfusion and can occur in the absence of protrusion of the device.

Comparative Study for Diagnostic Value Between Dual Energy CT Lung Perfusion Imaging and CT Pulmonary Angiography in Patients With Pulmonary Embolism / 中国循环杂志

Objective: To explore the value of dual energy CT lung perfusion imaging (DEPI) for diagnosing pulmonary embolism (PE) in comparison with CT pulmonary angiography (CTPA). Methods: There were 49 patients with suspected PE received DEPI scanning and 19 with CTPA conifrmed diagnosis were enrolled in this study. CTPA image was obtained by 80 kv data, and DEPI image was obtained by PBV software. The location, type of PE in CTPA image, and the location, shape of perfusion defect in DEPI were observed and compared by segment basis. The correlation and agreement of CTPA and DEPI for diagnosing PE were calculated and the un-agreement was analyzed. Results: A total of 380 segments were included for analysis. CTPA detected 162 segments of PE and DEPI detected 155 segments of perfusion defect or reduction, partial PE were mainly presented by perfusion defects as speckles, patches or without perfusion defect, and complete PE were mainly showed segmental or sub-segmental perfusion defects. CTPA and DEPI were correlated for PE diagnosis (χ2=305.5,P=0.000), the diagnostic agreement was 83.42% and KAPPA value was 0.659. Conclusion: The perfusion defect in DEPI is related to the degree and type of PE presented in CTPA, their combination is helpful for diagnosing PE.

Right-to-left shunting secondary to microvascular pulmonary arteriovenous malformation demonstrated by lung perfusion scintigraphy

Right-to-left shunting is usually associated with congenital conditions involving the heart, lungs, and the blood vessels that connect both organs. It is demonstrated by echocardiography, transesophageal ultrasound, CT scan, MRI and more definitively by conventional angiography. In this paper, we present a 16-year old female who manifested with progressive dyspnea, persistent cyanosis and decreased arterial oxygen saturation. Clinical assessment and arterial blood gas parameters suggested the presence of significant shunting. However, cardiac evaluation showed no intracardiac defects. High resolution CT scan of the chest with CT angiography of the pulmonary artery also showed no evidence of pulmonary vascular malformation or shunt anomaly. Lung perfusion scintigraphy performed after intravenous administration Tc99m-MAA showed tracer uptake in the brain, spleen and kidneys signifying the presence of a right-to-left shunt in the lungs. Cardiac catheterization later demonstrated the presence of primary pulmonary telangiectasia.

Influencia del movimiento respiratorio sobre el contraste de las lesiones en estudios de perfusión pulmonar: simulación mediante el uso de un fantoma virtual / Respiratory motion on the contrast of pulmonary lesions in lung perfusion scintigraphy: a simulation study with a virtual phantom

El movimiento respiratorio (MR) constituye un factor de degradación de las imágenes con potencial influencia sobre la capacidad de detección de lesiones tromboembólicas en estudios de perfusión pulmonar. El objetivo fue investigar la influencia del MR sobre el contraste de lesiones pulmonares, por medio de simulación con un fantoma virtual. Mediante un fantoma N-CAT se generó un modelo de perfusión pulmonar con SPECT; el modelo fue reconstruido produciendo cortes tomográficos y reproyección de los mismos en tres situaciones: sin MR, simulando MR con desplazamiento diafragmático de 2 cm, y con desplazamiento de 4 cm. Se instalaron en el modelo 7 "lesiones" hipocaptantes simulando la situación del tromboembolismo pulmonar (TEP) en situación superior, media y basal y se calculó el contraste de las lesiones en las 3 situaciones descriptas. Los resultados muestran que el contraste de las lesiones es menor con el MR, que se deteriora más cuanto mayor es la magnitud del MR, y que el MR afecta en mayor grado el contraste de las lesiones de ubicación basal. La corrección de MR podría mejorar la detectabilidad de algunos defectos de perfusión, especialmente los de ubicación basal, incrementando la sensibilidad de la técnica para el diagnóstico de TEP.

Respiratory motion (RM) represents a major factor of image degradation with potential impact on the detection of embolic lesions in lung perfusion scintigraphy. The aim was to investigate the influence of RM on the contrast of pulmonary lesions through a simulation study with a virtual phantom. Using a N-CAT phantom, a SPECT lung perfusion model was generated; the model was reconstructed producing three sets of tomographic slices and image reprojection under different conditions: without RM, RM simulation with 2 cm diaphragmatic displacement, and RM simulation with 4 cm diaphragmatic displacement. Seven "cold" lesions were placed in the model resembling a typical pulmonary embolism (PE) situation in superior, medial and basal locations and image contrast was calculated. Results showed a decrease in lesion contrast proportional to the degree of RM, which was more pronounced for basal lesions. Motion correction could improve the detectability of some perfusión defects, especially those in basal locations, thus incrementing the sensitivity of the technique for the diagnosis of PE.

Bridging crossroads of congenital lobar emphysema--Lung perfusion scintigraphy: A guide towards the right path

Congenital lobar emphysema (CLE) is a life-threatening but potentially reversible lung abnormality of unknown etiology that can present a diagnostic dilemma. Imaging procedures are helpful for early diagnosis. This paper aims to present the scintigraphic features of CLE in a two-year-old male in correlation with other diagnostic modalities. Lung perfusion scintigraphy revealed globally diminished perfusion to the left lung. High Resolution Computed Tomography (HRCT) of the chest showed intrinsic narrowing of the distal left mainstem bronchus. CT scan of the Pulmonary Arteries (CTPA) showed a small left main pulmonary artery. Lung perfusion scintigraphy in CLE is characterized by markedly attenuated vascularity of the involved lobe with consequent decreased perfusion, and increased to normal perfusion in the unaffected lobe. It plays a vital role in the early diagnosis and management of pediatric pulmonary diseases presenting with a diagnostic dilemma, particularly in cases where it can preclude more invasive diagnostic procedures.