Lung Ventilation Scintigraphy Research Articles

Administered dosage and effective dose estimated from 81Rb-rubidium hydroxide for lung ventilation scintigraphy using 81mKr noble gas.

The aim of this study was to estimate the administered dosage of 81mKr noble gas as calculated by the radioactivity of 81Rb-rubidium hydroxide (81RbOH). The administered dosage was regarded as the total amount of 81mKr noble gas. The radioactivity of 81mKr was calculated using the radioactivity of 81RbOH at the examination, the beginning of inhalation, the inhalation duration and the attenuation volume from the generator to the patient for 81mKr noble gas. In addition, we created an Internet survey and asked National University Hospital in Japan to respond to questions regarding the parameters of concern. Survey responses were provided by 38 hospitals (response rate was 90.5%). Twenty-seven hospitals (64.3%) examined lung ventilation scintigraphy using 81mKr noble gas. The mean administered dosage and the effective dose of lung ventilation scintigraphy using 81mKr noble gas were 35.8±22.1GBq and 0.97±0.60mSv, respectively.

Performance and Feasibility of Therapeutic Vibrating Mesh Nebulizer for Ventilation Lung Scan

PurposeThis study aimed to evaluate the performance of a therapeutic vibrating mesh-type nebulizer for the pulmonary delivery of radioaerosols for lung scintigraphy in healthy subjects.MethodsSix healthy subjects (mean age of 28.7 ± 6.2 years) inhaled 2 mL Tc-99m diethylenetriaminepentaacetic acid and normal saline solution (20 mCi) via a therapeutic vibrating mesh-type nebulizer (DK010, DELBio, Taipei, Taiwan). The nebulizer’s mass median aerodynamic diameter was between 2.3 and 5.0 µm (3.47 ± 0.37 µm), and the nebulization rate was greater than 0.2 mL/min. Scintigraphy was performed to count radioaerosols in the regions of interest to determine the total and regional lung deposition and extrathoracic airway deposition of aerosols, penetration of aerosols, and radioactivity count balance (RCB).ResultsThe total lung depositions of aerosols were 21.2% ± 5.2% (% ex-valve dose), 27.4% ± 8.0% (% ex-device dose), and 13.8% ± 4.1% (% initial dose) in the nebulizer. The extrathoracic airway deposition was 4.8% ± 1.1%. The RCB was 5.4% ± 3.0%. The ratio of outer over inner lung deposition (O/I ratio, or penetration index) was 1.89 ± 0.55.ConclusionThe delivery efficiency and penetration of aerosols to the peripheral lung, which were achieved by the DELBio DK010 vibrating mesh-type nebulizer, were similar to the commercialized jet-type nebulizers dedicated for radioaerosol lung scintigraphy nebulizer. The therapeutic vibrating mesh-type nebulizer (DELBio DK010) is feasible for radionuclide lung ventilation scintigraphy.

Airflow patterns in the trachebronchial tree of a patient with an accessory cardiac bronchus: A rare congenital anomaly

Accessory cardiac bronchus (ACB) is a rare congenital anomaly mainly located in the medial wall of the intermediate bronchus. This anomaly can present with dyspnea, recurrent infections, and hemoptysis. It usually has a blind ending, which may have an impact on airflow patterns and lobar distribution regardless of its diameter and depth. There have been very few cases with ACB. However, the airflow pattern and lobar distribution have not been well studied. In our case with ACB, the proportion of airflow in the right lung was higher than in the model without ACB, while mean airflow velocities were similar in both models. In this regard, quantitative lung ventilation scintigraphy could be better than the anatomical formula in predicting postoperative forced expiratory volume 1 in patients with accessory cardiac bronchus who will undergo lung resection.

Tracheobronchitis signs observed on ventilation lung scintigraphy during the course of COVID-19 infection.

Tracheobronchitis signs observed on ventilation lung scintigraphy during the course of COVID-19 infection.

Early Shift of Lung Perfusion to the Unilateral Lung Predicts the Development of Unilateral Chronic Lung Allograft Dysfunction after Bilateral Living-Donor Lobar Lung Transplantation

Purpose In the diagnosis of chronic lung allograft dysfunction (CLAD) after living-donor lobar lung transplantation (LDLLT), lung ventilation scintigraphy using 133 Xe has been shown to be useful. However, the supply of 133 Xe has been discontinued worldwide in 2016 and a new diagnostic tool is required for CLAD after LDLLT. Generally, because CLAD has been shown to develop predominantly on one side after bilateral LDLLT, lung perfusion scintigraphy (LPS) could show a perfusion shift to the unilateral healthy lung ( Figure 1A ). Nevertheless, the usefulness of LPS in the diagnosis of CLAD after LDLLT is unknown. Methods We conducted a single-center retrospective cohort study of 58 recipients who underwent bilateral LDLLT at Okayama University Hospital between October 1998 and June 2016. The unilateral shift values in LPS were calculated, and compared between the CLAD group (N=27) and the non-CLAD group (N=31) from 5 years before the CLAD onset to 5 years after the CLAD onset. Results The median time to the CLAD onset was 2176 days (326-4763 days). The unilateral shift values in LPS of the CLAD group were significantly higher than those of the non-CLAD group during 5 years before the CLAD onset (P Figure 1B ). An ROC analysis of the performance of the unilateral shift value in LPS as a marker of CLAD yielded an AUC of 0.79 (sensitivity=0.54 and specificity=1.00 at a unilateral shift threshold level of 8.6%). The unilateral shift values in LPS were significantly correlated with the results of the forced expiratory volume in 1 second (P = 0.036, r = - 0.322) ( Figure 1C ). Conclusion In the patients with unilateral CLAD after bilateral LDLLT, LPS showed the unilateral perfusion shift to the healthy lung even during 5 years before the CLAD onset. LPS might have a potential to diagnose unilateral CLAD early after bilateral LDLLT.

P084] Tests of down-scatter correction in simultaneously acquired TC-99M perfusion and KR-81M ventilation scans

Purpose Lung scans are basic nuclear medicine studies, often consisting of both ventilation and perfusion studies. A gamma camera acquires the ventilation studies of a radioactive gas or aerosol inhaled by a patient, and the perfusion studies of 99mTechnetium macro aggregated albumin injected in the patient’s blood. There are several possible gasses or aerosols for ventilation scintigraphy, but 81mKrypton is usually considered the golden standard. Due to the higher gamma energy of 81mKr compared to 99mTc, ventilation and perfusion scans can be acquired simultaneously, which saves time and allows perfect image registration. Unfortunately, down-scatter of 81mKr often distorts the perfusion images significantly. A widely used method to solve this problem is to subtract a fraction of the ventilation studies from the perfusion studies. However, we suspect this to be an inadequate procedure that may even lead to further degradation of the perfusion scans. Methods In our project, we acquired studies of a patient and of homemade phantoms. While the patient underwent a lung ventilation scintigraphy, an extra energy window at 140 keV was added, leading to a scintigraphy of down-scattered photons. The homemade phantom consisted of a 50 ml 81mKr filled syringe surrounded by two water boxes, representing respectively lungs and nearby tissue. Four energy windows were acquired simultaneously: 140 keV ± 10%, 190.5 keV ± 10%, 159 keV ± 2.5% and 168 keV ± 2.5%. Results Both of the methods showed none or little overlap between the scintigraphies with energy windows at 140 keV and 190.5 keV. This supported our theory of the subtraction method being without effect in the best case. Instead, other theoretically conceived procedures were tested, but the results were insufficient. Conclusions In the case of unacceptable quality of perfusion scintigraphies caused by down-scatter from 81mKr, one has to consider other solution than the typically used subtraction method. The short half-life of 81mKr (13 seconds) may even allow acquisition of ventilation studies prior to perfusion studies.

Which is Better - A Standalone Ventilation or Perfusion Scan or Combined Imaging to Predict Postoperative FEV1 in One Seconds in Patients Posted for Lung Surgeries with Borderline Pulmonary Reserve.

Introduction:Forced expiratory volume in one second (FEV1) is an independent predictor for respiratory morbidity. Reports are varied and controversial substantiating the use of either lung perfusion (Q) or ventilation (V) scintigraphy as a single stage investigation to predict postoperative (ppo) FEV1 in patients scheduled for lung resection surgeries. It is said that there is no additional benefit by performing both V/Q scan. As per one of the recommendations, no further respiratory function tests are required for a lobectomy if the postbronchodilator FEV1 is >1.5 l. We wanted to study the ppo FEV1 in patients with FEV1 of <1.5 L scheduled for lung surgeries. Being a high-risk population, we wanted to assess (a) whether the ppo changes by this combined V/Q imaging and (b) whether the incidence of respiratory complication in the postoperative setting of this subgroup is different, (c) and study the short- and long-term clinical outcome.Materials and Methods:Fifty-two high-risk patients (with comorbidities) and borderline preoperative FEV1 of 1.5 L or less planned for lung resection were enroled in this prospective study. V and Q scans were performed, and tracer uptake percentage was tabulated.Results:Tracer uptake in each lung was quantitated. Manual method of ROI drawing is preferred in high risk patients with reduced pulmonary reserve over the automatic method. Based on uptake patterns by V/Q scans, 4 different types of patterns were tabulated. Eighty-eight percentage of centrally placed tumors showed the difference in uptake patterns. Chronic obstructive pulmonary disease patients usually showed more modest ventilatory defects (categorised as type 2 or 3). Lung tumours produce erratic uptake patterns (Type 4) which depend heavily on their location and extent. The range of FEV1 predicted was 0.6–1.38 L/minConclusion:We recommend that combined imaging should be performed in patients with borderline pulmonary reserve to derive the benefit of surgery as it provides a realistic ppo FEV1 in patients with moderate to severely damaged lung. Centrally placed hilar or bronchial tumors (even those <2 cm in size), produce discrepancies in V/Q distribution pattern. Patient who was thought ineligible for surgery due to low baseline FEV1 may be actually be operable by this combined imaging if uptake pattern is better in V or Q scan with a good outcome. Accurate estimation of postop FEV1 in fact helps the surgical team to implement measures to prepare high risk patients to reduce postoperative complications, enable faster weaning from ventilatory support and ensure favourable prognosis.

Veteran player tips the scale — V/Q SPECT-CT proves decisive in blunt chest trauma. Case report and brief literature review

A 29-year-old patient after blunt chest trauma with right lung atelectasis and pulmonary empyema was referred for lung ventilation and perfusion scintigraphy before right-sided pneumonectomy. Radionuclide imaging revealed severely reduced perfusion and lack of ventilation in the collapsed right lung. Additionally, it showed a matching lobar perfusion-ventilation defect in the lower left lobe, which, apart from consolidation area in posterior basal segment, appeared normal in computed tomography. A normal perfusion and ventilation pattern was observed in the upper left lobe. Since it was found to be the only functioning lobe, pneumonectomy was excluded from possible treatment options.

Safety management of nuclear medicine personnel with visualisation of air dose rate.

Many people are anxious about radiation exposure for the reason that radiation cannot be seen. With the aim of devising a way for medical personnel to perform their medical duties without worry about radiation exposure, we attempted safety management using a system that displays the air dose of radiation in real time. Measurements were made in a lung ventilation scintigraphy examination room with the use of Xe-133. An SCI-type RI detector from Hamamatsu Photonics, which displays the air dose rate in real time, was used for the measurements. These radiation measurements were continued from the start to finish of the examination. The measurements were made in two locations, on the patient inhalation tube side and on the opposite side. Measurements were made on the patient tube side in 24 tests and on the opposite side in 12 tests. The maximum air dose rate was 3.7 ± 2.1 μSv/h on the patient tube side and 1.1 ± 0.5 μSv/h on the opposite side. Thus, the level on the opposite side was about 1/5 that of the tube side. To accurately perform lung ventilation scintigraphy, a medical worker needs to observe the patient's breathing status up close. Because of this, some medical workers are worried about radiation exposure during tests. The simplest way to reduce exposure would be to maintain a distance from the examination tube that is the source of radiation. The measurements in this study were made to encourage medical workers' recognition of this fact. Displaying specific numbers not only serves as basic data for managing staff operations, but is also thought to reassure workers through visualization.

Potential Role of Lung Ventilation Scintigraphy in the Assessment of COPD.

Objective:To highlight the importance of the lung ventilation scintigraphy (LVS) to study the regional distribution of lung ventilation and to describe most frequent abnormal patterns of lung ventilation distribution obtained by this technique in COPD and to compare the information obtained by LVS with the that obtained by traditional lung function tests.Material and methods:The research was done in 20 patients with previously diagnosed COPD who were treated in Intensive care unit of Clinic for pulmonary diseases and TB “Podhrastovi” Clinical Center, University of Sarajevo in exacerbation of COPD during first three months of 2014. Each patient was undergone to testing of pulmonary function by body plethysmography and ventilation/perfusion lung scintigraphy with radio pharmaceutics Technegas, 111 MBq Tc -99m-MAA. We compared the results obtained by these two methods.Results:All patients with COPD have a damaged lung function tests examined by body plethysmography implying airflow obstruction, but LVS indicates not only airflow obstruction and reduced ventilation, but also indicates the disorders in distribution in lung ventilation.Conclusion:LVS may add further information to the functional evaluation of COPD to that provided by traditional lung function tests and may contribute to characterizing the different phenotypes of COPD.

Development, characterisation and pharmacoscintigraphic evaluation of nano-fluticasone propionate dry powder inhalation as potential antidote against inhaled toxic gases

Acute lung injuries caused due to inhalation of toxic irritant gases such as ammonia, chlorine, hot smoke and burning plastic fumes predominantly affect the airways, causing tracheitis, bronchitis, and other inflammatory responses. The purpose was to develop and characterise nanoparticle based fluticasone propionate (FP) DPI formulation and assess its in vitro and in vivo pulmonary deposition using pharmacoscintigraphy. FP nanoparticles were prepared by nanoprecipitation method. Optimisation was carried out with the help of Box–Behnken statistical design. Nanoparticles were characterised with the help of SEM, FT-IR, DSC and XRD. Anderson cascade impaction showed that nano-FP exhibited significantly higher respirable fraction of 60.3 ± 2.41 as compared to 16.4 ± 0.66 for micronised form. Ventilation lung scintigraphy in human volunteers confirmed significant increase in drug delivery till alveolar region with nano-FP in comparison to micronised drug. Results indicate that the developed formulation may have a potential prophylactic/therapeutic role against toxic, irritant gas inhalation.

Edetate calcium disodium nanoparticle dry powder inhalation: A novel approach against heavy metal decorporation

Objective was to develop and characterize nano-edetate calcium disodium (Ca-Na 2EDTA) dry powder inhaler (DPI), and assess its in vitro and in vivo deposition using pharmacoscintigraphy techniques. Factors influencing nanoparticle formation including concentration of drug, polymer solution and stirring rate were determined. Optimized formulation was characterized with the help of SEM, TEM and Malvern Zetasizer studies. Any change in physical characteristics after nanosizing was determined by FT-IR, XRD and DSC studies. Anderson cascade impaction showed that nano Ca-Na 2EDTA exhibited significantly higher respirable fraction of 67.35 ± 2.27% and 66.40 ± 2.87% by scintigraphic and spectroscopic analysis respectively, as compared to 10.08 ± 1.17% and 9.36 ± 1.02% respectively for micronized form. Ventilation lung scintigraphy done in 12 volunteers showed significant increase in drug delivery till alveolar region with nano Ca-Na 2EDTA. The developed formulation may have a role in neutralizing heavy metal toxicity through inhalation route, including radio-metal contamination.

Don’t Forget Scintigraphy in Pulmonary Embolism

In their review article (1) the authors recommended a diagnostic algorithm for the scenario of suspected embolism of the pulmonary artery. Lung ventilation and perfusion scintigraphy is mentioned only as an aside, and the authors say that multidetector computed tomography has taken over as the gold standard imaging method. They back up their statement with a 2008 guideline from the European Society of Cardiology (2). However, in the cited guideline, the value of scintigraphy is explained in a rather more differentiated manner. The guideline emphasizes in particular the high negative predictive value of a normal perfusion scintigram. A prospective multicenter study, which is often cited as a justification for the use of spiral computed tomography (CT), has also again confirmed the safety of diagnostic algorithms while using scintigraphy (3). We would also ask that more attention be paid to the possible contraindications and side effects of the contrast media required for CT scanning (renal failure, hyperthyroidism, contrast medium allergy). These may even be life threatening. Scintigraphy is a valuable alternative, but the way the information is presented runs the risk that it is all but forgotten about. Mentioning technical progress in nuclear medical imaging with three-dimensional assessment of perfusion and ventilation—also when using the SPECT/CT technique—may exceed the remit of the review article. However, all these contribute to making the procedure safe. The effective dose usually does not matter in an emergency situation. CT and scintigraphy do not differ much in that setting. But the dose to parts of the body should be considered, as well as the dose to the breast in young women and that to the uterus in pregnant women in their third trimester. Even though the review article aimed to provide a simple algorithm of diagnostic procedures, we hope to have made a valuable contribution to the material.

Lung ventilation scintigraphy in the assessment of obstructive lung diseases

Educational aimsTo describe more recent techniques used to study the regional distribution of ventilation.To learn the most frequent abnormal patterns of lung ventilation scintigraphy (LVS) in obstructive lung diseases.To compare the information obtained by this technique with that obtained by traditional lung function tests.To understand that LVS may provide further information on lung pathophysiology.SummaryLVS is a well known technique that is used to study the distribution of ventilation in pulmonary diseases. However, its application in current practice has been poorly developed, mainly because of methodological problems. Redistribution of convective ventilation is the leading disorder in patients with chronic obstructive pulmonary disease (COPD) and is the target of most treatments, either by drugs or mechanical ventilation. The current availability of a new delivery inhaler (FAI; Medical Products Research, Legnano, Italy) with fine particles allows: 1) fast aerosol administration; 2) high-quality early images; 3) improved visualisation of pulmonary periphery; and 4) wider physiological distribution of the radioaerosol. Several patterns of distribution of pulmonary ventilation can be described in different airway disorders (asthma and COPD). These abnormalities are often too subtle to be picked up by traditional lung function tests, both in the baseline evaluation and after different interventions. Wider use of this technique may increase the knowledge and the management of obstructive lung diseases.

Ventilation scintigraphy with lipophilic cationic compounds

On the basis of our hypothesis that lipophilic cations may be more suitable for ventilation lung scintigraphy than the conventional technetium-99m diethylenetriamine penta-acetic acid (Tc-DTPA), comparative studies were carried out. The nebulization potential of nine routine radiopharmaceuticals was compared on medical and scintigraphy-specific nebulizers. This was followed by ventilation scintigraphy in 14 patients with chronic obstructive airway disease (n=13) or pulmonary embolism (n=1) where either 99mTc-methoxyisobutylisonitrile (n=10) or Tc-tetrofosmin (n=4) was used. Same-patient comparison with 99mTc-DTPA ventilation scan was available in six patients using the same acquisition protocol. Comparison with 99mTc-DTPA was made with respect to the nebulization rates, radioactivity delivered per unit of radioactivity available for inhalation, and regional distribution of inhaled counts. Lipophilic cation solutions had a significantly higher nebulization rate compared with 99mTc-DTPA using the medical nebulizer (235%, P<0.01) and 370% on scintigraphy-specific nebulizer (P<0.01). More than three times the counts of 99mTc-methoxyisobutylisonitrile or 99mTc-tetrofosmin was deposited in the body compared with Tc-DTPA aerosol per megabecquerel activity inhaled (1.5 vs. 0.4 kcounts/MBq) (P<0.001), preferentially in the lungs (75.2 vs. 65.2%), at the expense of oropharynx and stomach. Within the lungs, about 50% more counts were deposited in the outer one-third lung with lipophilic cations. Overall, therefore, more than 12 times the radioactivity deposition was achieved in the peripheral one-third of the lungs with the lipophilic cations. Ventilation lung scanning with lipophilic cations is a viable substitute of nanoparticle scintigraphy (technegas and pertechnegas, which are expensive and technically far more demanding).

Assessment of mean transit time in the engrafted lung with 133Xe lung ventilation scintigraphy improves diagnosis of bronchiolitis obliterans syndrome in living-donor lobar lung transplant recipients

Staging of bronchiolitis obliterans syndrome (BOS) following lung transplantation is based on declines in forced expiratory volume in 1 s (FEV(1)). The aim of this study was to evaluate the usefulness of (133)Xe ventilation scintigraphy in the early detection of BOS following living-donor lobar lung transplantation (LDLLT), to compare (133)Xe washout imaging with computed tomography (CT) findings for early detection of BOS following LDLLT, and to evaluate (133)Xe washout imaging by quantitative analyses. Subjects comprised 30 double-lung recipients and 1 single-lung recipient, who had undergone LDLLT at our institution and survived more than 1 year. Clinically diagnosed BOS developed in six recipients. Declines in graft function were evaluated using a combination of three methods, namely, dynamic spirometry, high-resolution CT (HRCT), and (133)Xe ventilation scintigraphy. Findings for all transplanted lungs were compared between CT and (133)Xe washout imaging. (133)Xe washout imaging was assessed using mean transit time (MTT) of bi-and unilateral lungs. Correlations between MTT of bilateral lungs and FEV(1)% were evaluated. Differences in MTT between BOS and non-BOS lungs, and between non-BOS and donor lungs were also evaluated on unilateral lungs. Appropriate cut-off values of MTT of unilateral lungs were set for the diagnosis of BOS. In all six BOS cases, prolonged-washout images of engrafted lungs revealed early-phase BOS with declines from baseline FEV(1), whereas only one BOS case could be detected using early CT findings of BO (bronchodilatation, decrease in number and size of pulmonary vessels, thickening of septal lines, and volume reduction). A significant correlation was identified between MTT and FEV(1)% (r = -0.346, P < 0.0001). MTT of unilateral lungs was significantly longer in BOS lungs than in non-BOS lungs (P < 0.0001). The cut-off MTT of unilateral lungs for the diagnosis of BOS was set at 64.77 s. Our data show that (133)Xe washout imaging offers excellent potential for early detection of BOS compared with early CT findings. Using (133)Xe washout imaging and MTT with radioactive tracer offers a noninvasive indication of selective ventilatory function in engrafted lungs following LDLLT. MTT appears useful for identifying BOS following LDLLT and allows quantitative evaluation of graft function in unilateral lungs.

Diagnostic and Prognostic Impact of Nuclear Medicine in the Management of Acute Chest Pain

SummaryLife‐threatening and prevalent causes of acute chest pain can be ruled out by nuclear medicine techniques. Among them acute coronary syndromes (ACS), acute myocardial infarction (AMI) or suspected pulmonary embolism (PE) are the main indications for the use of nuclear medicine techniques in patients presenting with chest pain to the emergency department (ED). Myocardial perfusion imaging (MPI) using nuclear techniques is a well established diagnostic tool in the management of patients with ACS or AMI providing non‐invasively information about perfusion and function. Single photon emission computed tomography (SPECT) is routinely applied for MPI allowing the characterization of localization, extent and severity of perfusion abnormalities. SPECT MPI is accurate and feasible in the clinical settings of patients presenting with chest pain. Pulmonary embolism is a common clinical disorder that is associated with high morbidity and mortality if untreated. Because of the unspecific symptoms commonly observed with the disease confirmation or exclusion of PE needs to be done in many cases admitted to ED. Various diagnostic strategies are available to confirm or rule out PE. Discordance between clinical probability and the results of diagnostic tests require imaging studies. Both lung perfusion and ventilation scintigraphy are safe, feasible and reliable methods enabling to exclude PE in patients with a low clinical probability. In summary, the documented prognostic value of scintigraphic parameters is of clinical importance to guide decision‐making in the patient with acute chest pain. Additionally, the cost‐effectiveness of nuclear medicine techniques in the work‐up of patients with chest pain has been demonstrated.

Long-term follow-up of patients with high-risk congenital diaphragmatic hernia

Background/Purpose Recent advances including prenatal diagnosis, high-frequency oscillatory ventilation, and nitric oxide inhalation therapy have gradually improved the survival of high-risk congenital diaphragmatic hernia. However, the factors affecting the long-term outcome of these patients have not been well established. Methods Thirty-three children with ages 4.1 ± 2.5 years underwent clinical examination including growth measurements, echocardiography, ventilation, and perfusion scintigraphy. Results No late death was observed. Common complications were frequent respiratory tract infection (13 patients) and bowel obstruction (5 patients underwent surgery). Although frequent respiratory tract infection decreased with increasing age, patients with frequent respiratory tract infection had a decreased uptake of lung ventilation and perfusion scintigraphy on the affected side and had a decreased height for age and weight for height. No significant difference in lung ventilation and perfusion scintigraphy was observed between patients treated with and without extracorporeal membrane oxygenation, those requiring oxygen more than 1 month, and between those with and without prenatal diagnosis. Patients with a patch repair had decreased uptake on lung perfusion scintigraphy. Although frequent respiratory tract infection may be owing to hypoplasia of the ipsilateral lung, it may impair recovery of the hypoplastic lung. Conclusion These results indicate that monitoring for respiratory tract infection in addition to nutritional assessment should be required in the follow-up of patients with congenital diaphragmatic hernia at high risk.

Ventilation imaging of the lung: Comparison of hyperpolarized helium-3 MR imaging with Xe-133 scintigraphy 1

Rationale and objectives To compare hyperpolarized helium-3 (HHe) magnetic resonance imaging (MRI) of the lung with standard Xe-133 lung ventilation scintigraphy. Materials and methods We performed a retrospective review of 15 subjects who underwent HHe MRI and Xe-133 lung ventilation imaging. Coronal MRI sections were acquired after a single inhalation of HHe gas, and standard posterior planar lung ventilation scintigraphy was performed during continuous breathing of Xe-133 gas. The first breath scintigram of each patient was compared with a composite MR image composed of the sum of the individual MR images and with the individual helium-3 MR images. Ventilation defects on the two imaging modalities were compared for size, conspicuity, and concordance in presence and location. Assessment was done separately for each of four lung quadrants. Results Comparing the composite HHe MR images with Xe-133 scintigraphy, ventilation defect size, conspicuity and concordance were the same in 67% (40/60), 63% (38/60), and 62% (37/60) quadrants, respectively. Comparing the individual HHe MR image sections with the Xe-133 ventilation scan, there was concordance between the ventilation defects in 27% (16/60) of quadrants. More defects were identified on the individual HHe MR images in 62% (37/60) of quadrants. Conclusion There was good agreement between composite HHe MR image and first breath Xe-133 scintigraphic images, supporting the widely held assumption that HHe MRI likely depicts first breath lung ventilation.

Functional evaluation of lung by Xe-133 lung ventilation scintigraphy before and after lung volume reduction surgery (LVRS) in patients with pulmonary emphysema.

We evaluated the respiratory functions of patients with pulmonary emphysema who underwent lung volume reduction surgery (LVRS) by the mean transit time (MTT) with Xe-133 lung ventilation scintigraphy, forced expiration volume in 1 sec (FEV1.0), residual volume (RV), distance walked in 6 min (6-min walk), and the Hugh-Jones classification (H-J classification) before and after LVRS. In 69 patients with pulmonary emphysema (62 men, 7 women; age range, 47-75 years; mean age, 65.4 years +/- 6.1, preoperative H-J classification, III (two were II)-V) who underwent LVRS, all preoperative and postoperative parameters (MTT 3 weeks after LVRS and the others 3 months after LVRS) were judged statistically by the Wilcoxon signed-ranks test and Odds ratio. Every postoperative parameter was improved with a significant difference (P < 0.05) compared to preoperative parameters. MTT at 3 weeks after LVRS was not associated with %FEV1.0 and the H-J classification at 3 months after LVRS, but was associated with RV and a 6-min walk at 3 months after LVRS. MTT was useful for the clinical evalution of aerobic capability after LVRS.