MR analysis of lung volume and thoracic dimensions in patients with emphysema before and after lung volume reduction surgery

OBJECTIVE: This study was performed to assess the accuracy of determining lung volume in patients with emphysema using MR imaging and then to investigate changes in thoracic dimensions after lung volume reduction surgery. SUBJECTS AND METHODS: Fast gradient-echo breath-hold MR imaging through the entire thorax at full inspiration and expiration was performed in 21 patients with severe emphysema and was performed again in nine of the patients who underwent surgery. Lung volumes were determined using a semiautomated computerized method of delineating the lungs and summing cross-sectional areas. These summed areas were compared with volumes measured on plethysmography and CT. Postoperative changes in thoracic structure were determined by measuring anteroposterior and transverse lung dimensions and lung height before and after surgery. RESULTS: The correlation coefficients and SEM for determining inspiratory lung volume were MR imaging versus plethysmography, r = .77, SEM = -12% (volume measured as less on MR imaging); CT versus plethysmography, r = .86, SEM = -13% (volume measured as less on CT); and MR imaging versus CT, r = .87, SEM = 4% (volume measured as greater on MR imaging). The correlation coefficients and SEM for determining expiratory volume on MR imaging versus plethysmography were r = .77, SEM = 6% (volume measured as greater on MR imaging). After surgery, decreases were found in all thoracic dimensions, and such decreases were greatest at expiration. CONCLUSION: MR measurements of lung volume are comparable with those of CT and differ from those of plethysmography. Changes in thoracic dimensions after lung volume reduction surgery are consistent with improved respiratory mechanics.     

Bounds on null functions of linear digital imaging systems

OBJECTIVE: The purpose of this investigation was to quantitatively assess abnormally low attenuation of the lung by use of three-dimensional volumetric reconstructions from routine helical CT and to assess their correlation with pulmonary function tests. MATERIALS AND METHODS: Helical CT was performed in 100 patients in full inspiration. Examination was also performed in full expiration in 53 of these patients. Three-dimensional volumetric reconstructions were performed for total lung volumes at inspiration and at expiration, with a threshold of -896 H on inspiratory CT and -790 H on expiratory CT, to quantify emphysematous change. Correlation was made with pulmonary function tests in 79 patients. RESULTS: CT volumetric assessments of abnormally low attenuation of the lung at inspiration and expiration had a high correlation (r2 = .84, p < or = .0001). In comparison with pulmonary function tests, both inspiratory low attenuation of the lung and expiratory low attenuation of the lung correlated well with the logarithm of the ratio of the forced expiratory volume in 1 sec (FEV1) to the forced vital capacity (r2 = .74, p < or = .0001 and r2 = .74, p < or = .0001, respectively) and with the percentage of predicted ratio of the FEV1 to the forced vital capacity (r2 = .69, p < or = .0001 and r2 = .69, p < or = .0001, respectively). Linear correlations were also seen with FEV1, residual volume, and forced residual capacity. CONCLUSION: Three-dimensional volumetric reconstructions of hypoattenuating lung correlate well with pulmonary function tests. In addition, inspiratory and expiratory data are also correlative, suggesting that a dedicated expiratory examination is not needed. This easily obtainable information will prove useful for patients with obstructive lung disease from emphysema, providing a measure of pulmonary function status in this population.     

Mechanical performance of clinically available, neonatal, high-frequency, oscillatory-type ventilators

OBJECTIVE: To perform a functional evaluation of five different high-frequency, oscillatory-type ventilators that are currently being marketed for neonatal high-frequency oscillation. DESIGN: Observational animal study. SETTING: Laboratory. SUBJECTS: New Zealand White male rabbits. INTERVENTIONS: Oscillator waveforms and delivered volumes were measured plethysmographically for the following ventilators: the SensorMedics 3100 A; the Dr?ger Baby Log 8000; the Metran Humming V; the Infant Star; and the Infant Star 950. The independent variables which were adjusted included frequency (5 to 15 Hz), amplitude (25% to 100%), mean airway pressure (5 to 25 cm H2O) and lung injury. MEASUREMENTS AND MAIN RESULTS: At 15 Hz, the volume delivered at the 100% amplitude setting varied from 2.1 to 8.8 mL. Generally, the delivered volume decreased with increasing frequency, and with increased percentage of amplitude. Volume delivery was relatively unaffected by mean airway pressure but decreased with lung injury. Waveforms ranged from pure sinusoidal to a complex square wave. The handling of inspiration/expiration time ratios was ventilator specific. The SensorMedics inspiration/ expiration ratio is user selected over a range from 1:2.3 (30% inspiratory time) to 1:1 (50% inspiratory time) and once selected it is consistent over its entire range of operating frequencies. The Drager ratio is machine determined and varied from 1:2.5 at 5 Hz to 1:1 at 15 Hz. Inspiratory time of the Infant Star is machine set at 18 msecs such that the inspiration/expiration ratio is 1:10.1 at 5 Hz and 1:2.7 at 15 Hz. The Humming V has a fixed inspiration/expiration ratio of 1:1. The relationship of the mean airway pressure displayed on the ventilator to the alveolar occlusion pressure varied considerably among devices. The displayed mean pressure could either overestimate (SensorMedics at 33% inspiratory time or Infant Star), approximate (Humming V), or underestimate (Dr?ger) the mean lung distending pressure measured during a brief occlusion maneuver. CONCLUSIONS: The findings demonstrate large variations in machine performance. The ventilators also differed profoundly in complexity of operation and versatility as neonatal ventilators.     

High-frequency oscillatory ventilation of newborn infants

Ventilator-induced lung injuries remain an important factor regarding morbidity and mortality in newborns requiring assisted ventilation. Numerous different modes of ventilation have been tried without achieving recognition. High-frequency oscillatory ventilation (HFO) is a new mode of ventilation which employs active inspiration and expiration at frequencies up to 20 Hz with a tidal volume below dead space. Progression of severe respiratory distress syndrome may be reduced by applying early HFO beside modern treatment modes. It has been demonstrated that immediate initial treatment of premature babies with high tidal volumes can cause lung damage. Clinical studies of HFO indicate, that it is possible to improve oxygenation, reduce short-term mortality, surfactant redosing, ventilator-time, use of extra corporeal membrane oxygenation (ECMO) and costs of hospitalization. Morbidity related to lung injury and cerebral damage is apparently unchanged compared to conventional mechanical ventilation. The use of HFO in milder cases awaits further clinical studies.     

Expression of CTLA-4 molecule in peripheral blood T lymphocytes from patients with systemic lupus erythematosus

The purpose of this study was to compare two planning techniques for the delivery of radical localized postoperative radiotherapy in the treatment of high grade astrocytomas. Conventional orthogonal plain film planning (CONP) was compared with CT planning (CTP) in terms of the size of the target volumes treated, the amount of normal brain irradiated and the accuracy of localization. Twenty consecutive adults with high grade astrocytomas, who were treated with radiotherapy between March and October 1996, were planned with CONP and CTP, using postoperative, contrast-enhanced CT scans to define the tumour volume. The planning target areas, volumes and the 100%, 80% and 50% isodose areas produced using the two planning methods were measured and compared using Student's paired t-test. The target volume length was also measured and compared as an independent factor. The difference between entry points of the central axis of the lateral fields was noted. Nineteen of 20 patients had a reduction in planning target volumes using CTP compared with CONP. The difference between the mean volumes was clinically relevant, with 288 cm3 representing a 25% reduction, and statistically significant at the P<0.001 level. The planning target volumes were reduced in 18/20 patients (mean 24 cm2, 23%, P<0.001). Similarly, there were highly significant reductions in the 100%, 80% and 50% isodose areas. The target volume lengths were not found to be significantly different. When considering the accuracy of localization, the entry point of the CONP lateral field deviated by a mean distance of 1.6 cm relative to CTP (superiorinferior 1.3 cm; anteriorposterior 0.8 cm; range 04.1 cm). In two patients, this would have led to a geographical miss of macroscopic disease. In patients with high grade astrocytomas, CTP is preferred to conventional planning. It leads to appreciable reductions in the size of the planning target areas and volumes receiving radical doses of radiation, it significantly reduces the amount of normal brain tissue being irradiated and is more accurate in terms of tumour localization. These differences are likely to lead to a reduction in treatment morbidity. We recommend CTP for all patients receiving radical radiotherapy.     

Lung density for assessment of hydration status in hemodialysis patients using the computed tomographic densitometry technique

The density of the lung reflects the total mass of fluid, air, and dry lung tissue per unit volume of the lung. Lung density can be measured by evaluation of attenuation of an electron beam with computed tomography (CT). This technique has been shown to be sufficiently reliable and sensitive to distinguish normal from abnormal lung water. The aim of this study was to find out whether lung density properly reflects the hydration status in hemodialysis patients in comparison with other standard methods. Fourteen hemodialysis patients, with an ultrafiltration ranging from 0.3 to 4.5 liters per session, underwent CT measurements of lung density, ultrasonographic measurements of the diameter of the inferior vena cava after quiet expiration (IVCe) and quiet inspiration (IVCi), and measurements of the hematocrit and plasma levels of the biochemical hydration markers cyclic guanosine monophosphate (cGMP) and atrial natriuretic peptide (ANP). These measurements were performed before and 3.5 to 4 hours after termination of dialysis. Quantitative estimates of lung density were obtained within pixels with CT numbers ranging between -1000 and -100 Hounsfield Units (HU), and compared with normal data from 18 normal controls. In normal controls, the lung density ranged from -800 to -730 HU. In hemodialysis patients, lung density was significantly higher than normal before dialysis (-678 +/- 96 HU, P < 0.01) and significantly decreased after dialysis (-706 +/- 92 HU, P < 0.05), indicating a decrease in fluid content of the lung. The density was normalized in 5 patients. A significant correlation was found between lung density and IVCe both before and after dialysis (r = 0.8, P < 0.01 for both). Change in density was significantly correlated to amount of ultrafiltration (r = 0.67, P < 0.01) and percent change in blood volume (r = 0.63, P < 0.05), indicating that lung density is greatly affected by changes in the extracellular fluid volume, mainly the intravascular volume. In conclusion, lung water reflects the hydration status in hemodialysis patients and can be monitored by measuring the lung density by CT. Accordingly, normalization of lung density can help to achieve a proper dry weight in these patients.     

Interim report on the radiosurgical treatment of cerebral arteriovenous malformations. The influence of size, dose, time, and technical factors on obliteration rate

During the authors' initial 4-year experience with radiosurgery using the Leksell cobalt-60 gamma unit, they treated 121 patients with cerebral arteriovenous malformations (AVMs). The radiosurgical dose to the margin of the nidus was 20 Gy for lesions less than 2.0 cm in diameter (volume < or = 4.2 cm3); 18 Gy for malformations 2.1 to 3.0 cm in diameter (volume 4.2-14.1 cm3); and 16 Gy for malformations greater than 3.0 cm (volume > 14.1 cm3). Fifty-one patients underwent follow-up angiography between 1 and 3 years after treatment, and complete obliteration of the nidus was confirmed in 38 (74.5%) of these patients. Thirty-two (74.4%) of 43 AVMs with volumes of 10 cm3 or less and six (75%) of eight larger AVMs (volume 11-30 cm3) showed complete obliteration. Analysis of the time course of AVM nidus shrinkage and obliteration showed that most of the radiosurgically induced effect had occurred by 36 months after treatment. Retrospective analysis of the dose plans for 10 AVMs that were not obliterated by 36 months after gamma knife radiosurgery at the authors' institution (eight cases) or elsewhere (two cases) revealed that six AVMs had not been covered completely by the prescribed isodose. Six (5%) of the 121 patients developed neurological deficits as a direct result of radiosurgical treatment. The authors infer from these data that malformations up to 30 cm3 in volume (approximately 4.0 cm in average diameter) can be treated effectively with an acceptably low complication rate using a radiosurgical dose of 16 Gy to the margin of the nidus. The obliteration rate for the larger malformations that were treated with a dose of 16 to 18 Gy appears to be similar to that for smaller ones treated with 18 to 20 Gy. As more experience accrues using radiosurgery to treat AVMs, patient selection criteria and the variables associated with successful obliteration of the nidus should become more clearly defined.     

Relation between preoperative inspiratory lung resistance and the outcome of lung-volume-reduction surgery for emphysema

BACKGROUND: Surgery to reduce lung volume has recently been reintroduced to alleviate dyspnea and improve exercise tolerance in selected patients with emphysema. A reliable means of identifying patients who are likely to benefit from this surgery is needed. METHODS: We measured lung resistance during inspiration, static recoil pressure at total lung capacity, static lung compliance, expiratory flow rates, and lung volumes in 29 patients with chronic obstructive lung disease before lung-volume-reduction surgery. The changes in the forced expiratory volume in one second (FEV1) six months after surgery were related to the preoperatively determined physiologic measures. A response to surgery was defined as an increase in the FEV1 of at least 0.2 liter and of at least 12 percent above base-line values. RESULTS: Of the 29 patients, 23 had some improvement in FEV1 including 15 who met the criteria for a response to surgery. Among the variables considered, only preoperative lung resistance during inspiration predicted changes in expiratory flow rates after surgery. Inspiratory lung resistance correlated significantly and inversely with improvement in FEV1 after surgery (r=-0.63, P<0.001). A preoperative criterion of an inspiratory resistance of 10 cm of water per liter per second had a sensitivity of 88 percent (14 of 16 patients) and a specificity of 92 percent (12 of 13 patients) in identifying patients who were likely to have a response to surgery. CONCLUSIONS: Preoperative lung resistance during inspiration appears to be a useful measure for selecting patients with emphysema for lung-volume-reduction surgery.     

The bulbar respiratory centre in the rabbit. I. Changes of respiratory parameters caused by intermittent electrical bulbar stimulation during inspiration or expiration

In anesthetized rabbits, spirogram and diaphragmatic activity were examined during electrical stimulation of regions of the medulla oblongata. The stimulating volleys were triggered by the phase transitions of the animal's own respiration. 1. Each early inspiratory volley of 120 ms duration at 100 pulses per second caused an immediate and transient inhibition of the diaphragmatic activity. Respiration was slowed down due to prolongation of inspiration. The tidal volume increased above control. Stimuli delivered after 30-40% of a control inspiration had elapsed cut short this phase and entailed a shortening of the following expiration, too. Respiration was thus accelerated. 2. Each early expiratory volley caused an inspiratory twitch after a short latency. The respiratory rate was slightly increased due to shortening of expiration. The spirogram exhibited a distinct inspiratory effect (elevation of the end-inspiratory and end-expiratory levels). Stimuli delivered after 60--70% of a control expiration had elapsed slowed down respiration due to prolongation of inspiration but did not alter the end-expiratory level. The expiration remained almost unaltered. The effects were still observed while an artificial state of lung distension or collapse was maintained. 3. Volleys of increasing duration were delivered, starting with onset of expiration. The initial respiratory acceleration (shortening of both phases) and elevation of the end-expiratory level, observed when short volleys were applied, changed into slowing down of respiration (prolongation of both phases) and a shift of the end-expiratory level towards active expirations when the duration of the volley was somewhat longer than a normal expiration. The end-inspiratory level remained slightly elevated. Results suggest that during inspiration a progressively increasing inhibitory state is built up. During expiration, both an increasing inspiratory and an expiratory tendency are present as revealed by mixed inexpiratory stimulation effects.     

Analysis of perception in patients during an acute attack of bronchial asthma

An analysis of subjective sensations during an asthmatic attack in 51 asthma patients was performed. A difficult inspiration or inspiration and expiration was the most prevalent sensation, while isolated difficult expiration was only sparse finding. A tightness on the chest was often noticed as well. The probable explanation for these observation could be the breathing a high lung volume (hyperinflation), caused by closing small airway a mostly due to bronchoconstriction during the asthmatic attack. The authors suggest not to generally use the term "expiratory breathlessness" when describing the clinical picture of an asthmatic attack.     

Effects of NREM sleep on dynamic within-breath changes in upper airway patency in humans

The purpose of our study was to compare inspiratory- and expiratory-related changes in retropalatal cross-sectional area (CSA) during wakefulness to those during non-rapid-eye-movement (NREM) sleep. We studied 18 subjects in whom the severity of sleep-disordered breathing varied. Relative changes in CSA were visualized by using fiber-optic endoscopy. For each breath analyzed (wakefulness n = 4-13; sleep n = 7-16), the CSA was measured at fixed points within inspiration and expiration (0, 25, 50, and 100% of the inspiratory and expiratory duration); these measurements were expressed as a percentage of the CSA that occurred at the start of inspiration. During wakefulness, there was a statistically significant increase in the retropalatal CSA (compared with the start of inspiration) only during early expiration (group mean: expiration, 0% = 112.6 +/- 3.2 (SE) %; 25% = 122.8 +/- 6.2%; 50% = 110.6 +/- 3.8%). In contrast, during sleep, significant changes in CSA occurred during both inspiration and expiration (group mean: inspiration, 25% = 75.3 +/- 6.0%; 50% = 66.7 +/- 7.7%; 75% = 64.6 +/- 8.1%; expiration, 0% = 126.8 +/- 11.8%; 25% = 125.3 +/- 6.9%). The expiratory-related increase in CSA was followed by narrowing such that at end expiration the caliber of the airway was returned to that occurring at the beginning of inspiration (group mean at end expiration = 98.6 +/- 3.1%). The largest changes in CSA occurred in the subjects with an increased body mass index (BMI). We conclude that, during NREM sleep, significant changes in CSA occur during both inspiration and expiration and that the magnitude of these changes is significantly influenced by BMI.     

Dibutyryl cGMP raises cytosolic concentrations of Ca2+ in cultured nodose ganglion neurons of the rabbit

Airway hyperresponsiveness in asthma has been attributed to impaired ability of deep inspiration (DI) to stretch airway smooth muscle. We have retested this hypothesis by comparing the responses to methacholine of 10 asthmatic and 10 control subjects. After each dose subjects breathed tidally without deep inspiration for 4 min, followed by a forced partial expiration from which flow was measured at a constant volume, 35% baseline VC (Vp 35). This index is independent of both DI and increases in end-inspiratory lung volume (EILV). EILV increased significantly more in the asthmatic group than in the control group (15.0 versus 2.5% of baseline VC, p = 0. 019), a factor that if not taken into account would tend to mask the difference in the two responses. Comparisons were made after a cumulative dose of 50 microg methacholine, which was the highest dose common to all subjects. The asthmatic response was significantly greater than that seen in the control group, with reductions to 25.9 and 72.1% of baseline Vp 35, respectively (p = 0. 0007). We conclude that the sensitivity of asthmatic airways to methacholine is greater than that of normal airways even when DI is prohibited. Therefore, the hyperresponsiveness of asthmatic airways is not attributable simply to an inability of DI to stretch airway smooth muscle.     

Mid-Infrared Diode Laser Spectroscopy of X ; 1 A '' HC35 Cl

PURPOSE: Ultrasound (US)-guided permanent prostate implants typically use US prostate volumes to plan the implant procedure and CT prostate volumes for 3D dosimetric evaluation of the implant. Such a protocol requires that CT and US prostate volumes be registered. We have studied the impact of prostate volume registration on postimplant dosimetry for patients with low-grade prostate cancer treated with combined US and fluoroscopic-guided permanent implants. METHODS AND MATERIALS: A US image set was obtained with the patient in the lithotomy position to delineate the prostate volume that was subsequently used for treatment planning. Each plan was customized and optimized to ensure complete coverage of the US prostate volume. After implant, a CT scan was obtained for postimplant dosimetry with the patient lying supine. Sources were localized on CT by interactively creating orthogonal images of small cubes, whose dimensions were slightly larger than the source, to assure unique identification of each seed. Ultrasound and CT 3D surfaces were registered using either (a) the rectal surface and base of the prostate, or (b) the Foley balloon and urethra as the alignment reference. A dose distribution was assigned to the US prostate volume based on the CT source distribution, and the dose-volume histogram (DVH) was calculated. RESULT: Prostate volumes drawn from US images differ from those drawn from CT images with the CT volumes being typically larger than the US volumes. Urethral registration of the prostate volume based on aligning the prostatic urethra generates a dose distribution that best follows the preimplant plan and is geometrically the preferable choice for dosimetry. CONCLUSION: The dose distribution and the DVH for the US prostate is sensitive to the mode of registration limiting the ability to determine if acceptable dose coverage has been achieved.     

Exercise and cellular innate immune function

PURPOSE: To determine, in three-dimensions, the difference between prostate delineation in magnetic resonance (MR) and computer tomography (CT) images for radiotherapy treatment planning. PATIENTS AND METHODS: Three radiation oncologists, considered experts in the field, outlined the prostate without seminal vesicles both on CT, and axial, coronal, and sagittal MR images for 18 patients. To compare the resulting delineated prostates, the CT and MR scans were matched in three-dimensions using chamfer matching on bony structures. The volumes were measured and the interscan and interobserver variation was determined. The spatial difference between delineation in CT and MR (interscan variation) as well as the interobserver variation were quantified and mapped three-dimensionally (3D) using polar coordinates. A urethrogram was performed and the location of the tip of the dye column was compared with the apex delineated in CT and MR images. RESULTS: Interscan variation: CT volumes were larger than the axial MR volumes in 52 of 54 delineations. The average ratio between the CT and MR volumes was 1.4 (standard error of mean, SE: 0.04) which was significantly different from 1 (p < 0.005). Only small differences were observed between the volumes outlined in the various MR scans, although the coronal MR volumes were smallest. The CT derived prostate was 8 mm (standard deviation, SD: 6 mm) larger at the base of the seminal vesicles and 6 mm (SD 4 mm) larger at the apex of the prostate than the axial MRI. Similar figures were obtained for the CT and the other MRI scans. Interobserver variation: The average ratio between the volume derived by one observer for a particular scan and patient and the average volume was 0.95, 0.97, and 1.08 (SE 0.01) for the three observers, respectively. The 3D pattern of the overall observer variation (1 SD) for CT and axial MRI was similar and equal to 3.5 to 2.8 mm at the base of the seminal vesicles and 3 mm at the apex. CONCLUSION: CT-derived prostate volumes are larger than MR derived volumes, especially toward the seminal vesicles and the apex of the prostate. This interscan variation was found to be larger than the interobserver variation. Using MRI for delineation of the prostate reduces the amount of irradiated rectal wall, and could reduce rectal and urological complications.     

Measurement of lung expansion with computed tomography and comparison with quantitative histology

The total and regional lung volumes were estimated from computed tomography (CT), and the pleural pressure gradient was determined by using the milliliters of gas per gram of tissue estimated from the X-ray attenuation values and the pressure-volume curve of the lung. The data show that CT accurately estimated the volume of the resected lobe but overestimated its weight by 24 +/- 19%. The volume of gas per gram of tissue was less in the gravity-dependent regions due to a pleural pressure gradient of 0.24 +/- 0.08 cmH2O/cm of descent in the thorax. The proportion of tissue to air obtained with CT was similar to that obtained by quantitative histology. We conclude that the CT scan can be used to estimate total and regional lung volumes and that measurements of the proportions of tissue and air within the thorax by CT can be used in conjunction with quantitative histology to evaluate lung structure.     

Copper-dependent reciprocal transcriptional regulation of methane monooxygenase genes in Methylococcus capsulatus and Methylosinus trichosporium

PURPOSE: To better understand the dose and time dependence of radiation therapy (RT)-induced regional lung dysfunction as assessed by changes in regional lung perfusion. METHODS AND MATERIALS: Patients who were to receive RT for tumors in and around the thorax, wherein portions of healthy lung would be incidentally irradiated, were prospectively studied. Regional function was assessed pre- and post-RT with single photon emission computed tomography (SPECT) lung perfusion scans, obtained following the intravenous administration of approximately 4 mCi of technetium-99m macroaggregated albumin. Pre-RT computed tomography (CT) scans were used to calculate the three-dimensional (3D) dose distribution, reflecting tissue density inhomogeneity corrections. Each SPECT scan was correlated with the pre-RT CT scan, and the 3D dose distribution. Changes in regional lung perfusion were correlated with regional RT dose, at various time intervals following radiation. RESULTS: The data from 20 patients (7 breast cancer, 5 lymphoma, 1 esophagus, 1 sarcoma, and 6 lung cancer) have been analyzed. Patients with gross intrathoracic lung cancers causing obstruction of regional pulmonary arteries were not included. For most patients, there is a statistically significant dose-dependent reduction in regional blood flow at all time points following radiation. While a time dependence is suggested in the high dose range, the limited amount of data prevents meaningful statistical evaluation. CONCLUSIONS: Radiation therapy-induced regional lung dysfunction occurs in a dose-dependent manner and develops within 3-6 months following radiation. In contrast to classical "sigmoid" dose-response curves, described mainly for changes following whole lung irradiation, these data suggest a more gradual relationship between regional dysfunction and RT dose. Retraction of irradiated lung with secondary movement of unirradiated lung into the "3D-defined irradiated volume" may have introduced inaccuracies into this analysis. Additional studies are currently underway to assess this possibility and better refine this dose-response curve. Studies are underway to determine if changes in assessments of whole lung function, such as pulmonary function tests, can be predicted by summing the regional changes observed.     

Radiotherapy for non-small-cell bronchial cancers: definitions of volumes, patient selection. Recommendations of the International Association for the Study of Lung Cancer (IASLC)

Chemoradiation is the standard treatment of unresectable, locally advanced non-small cell lung cancer, with a mean dose of 60-66 Gy, excluding escalation dose schemes. The standard treated volume includes primary tumor, ipsilateral hilar and mediastinal nodes, supraclavicular and contralateral nodes as well, regardless of the node status. This work tries to answer the question of the optimal volume to be treated. Drainage routes analysis is in favor of large volumes, while toxicity analysis favors small volumes. Combined modality treatment may increase the observed toxicity. The optimal volume definition is difficult, and requires available conformal therapy tools. Patients selection is another important issue. A volume definition is then attempted, based on the IASLC (International Association for the Study of Lung Cancer) Annecy workshop experience, highlighting the interobservers discrepancies, and suggests basic recommendations to harmonize volume definition.     

Changes in left ventricular contractility with the phase of respiration

The end-systolic wall stress (sigma(es))-velocity of circumferential fiber shortening (V(cfsc)) relation was defined during the respiratory cycle, in order to obtain a totally noninvasive measure of left ventricular contractility. Eight young, healthy subjects were studied with echocardiography and calibrated carotid pulse tracings, while performing slow paced breathing. Left ventricular sigma(es) vs. V(efsc) relation was determined by fitting linear regression line to data points obtained at different times during the respiratory cycle. Data are given as mean+/-1SD. Left ventricular sigma(es) and V(efsc) exhibited small but significant changes during the respiratory cycle: sigma(es) was highest in late inspiration (56.9+/-4.8 g/cm2) and lowest in late expiration (49.2+/-3.7 g/cm2); inversely, V(cfsc) was lowest during late inspiration (1.18+/-0.17 circ/s) and highest during late expiration (1.34+/-0.20 circ/s). The relation was significant in each subject (r = -0.64+/-0.13) and remained inverse and significant, when it was determined separately for inspiration and expiration (r = -0.61+/-0.17 and -0.68+/-0.12, respectively). At identical end-systolic wall stress, the velocity of shortening was greater during inspiration then expiration, suggesting that contractility was reduced during the expiratory phase. The reduced expiratory contractility might reflect increased vagal influence on the ventricular myocardium.