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The application of CNNs in medical image analysis has assumed a pivotal role, despite constraints related to the large amount of labeled data required. The aim of this study is to present a CNN for recognition and quantification of ILD patterns and to evaluate their correlations to functional data. 27 patients with chronic hypersensitivity pneumonitis (FEV1%p=61.6±15.9, FVC%p=57.0±16.8) were acquired via HRCT at full inspiration. The CNN (6 layers: 2 convolutional, 1 average pooling, 3 fully connected) was trained and tested on 395 regions of interest (ROIs) identified by one experienced pneumologist on the CT images resulting in a test accuracy=0.816, F1-score=0.810. The CNN was then applied to the patients’ full scans. 5 ILD patterns were analyzed: air trapping (AT), consolidation (C), ground glass opacity (GGO), healthy (H) and reticulation (R). The percentage of ILD tissue (ILD%) on the whole volume was correlated (Spearman Test) to spirometry. Fig. 1 reports CNN results on a representative patient. In the overall population, negative correlation was found between ILD% and FVC%p (r=-0.436, p In conclusion, the proposed CNN allows the recognition of ILD with significant correlations to functional data. The classification of pathological ROIs into different ILD patterns may represent a first step towards the development of a computer aided diagnosis system.

Background: Tuberculosis is one of the biggest public health concerns in India with a prevalence of 195 cases per 100000. Silica is cytotoxic to macrophage which is primary defense mechanism to tubercular bacilli and, hence, exposure to silica dust increases risk for TB. Silica exposed persons are at 2.8 to 39 times greater risk of affected by pulmonary tuberculosis in comparison to healthy subjects. Methodology: A cross-sectional epidemiological study was conducted among 935 workers in sandstone mining. Full-size posteroanterior view (PA) chest X-ray in full inspiration was evaluated and evidence of tuberculosis was noted. Fourier transform infrared spectrophotometer was used for determining the free silica in 23 dust samples. Results: 6.4% X-rays showed evidence of TB and silica dust concentration was 0.11 to 0.16 mg/m3. The TB cases significantly increased from 2% to 6% to 12.7% as the work exposure increased from 20 years respectively. 8.5% of the TB cases were seen among the workers having more than 10 years of work exposure. The odds ratio (95% CI) for work exposure more than 10 years to less than 10 years was 4.53 (1.92–10.65). Conclusion: Reduction of silica particles from work environment can significantly reduce the number of TB cases and hence wet drilling should be practiced and personal protective equipment should be regularly used.

Background— The number of implantable cardioverter-defibrillators (ICDs) for the prevention of sudden cardiac death is continuing to increase. Given the technological complexity of ICDs, it is of critical importance to identify and control possible harmful electromagnetic interferences between various sources of electromagnetic fields and ICDs in daily life and occupational environments. Methods and Results— Interference thresholds of 110 ICD patients (1-, 2-, and 3-chamber ICDs) were evaluated in a specifically developed test site. Patients were exposed to single and combined electric and magnetic 50-Hz fields with strengths of up to 30 kV·m −1 and 2.55 mT. Tests were conducted considering worst-case conditions, including maximum sensitivity of the device or full inspiration. With devices being programmed to nominal sensitivity, ICDs remained unaffected in 91 patients (83%). Five of 110 devices (5%) showed transient loss of accurate right ventricular sensing, whereas 14 of 31 (45%) of the 2- and 3-chamber devices displayed impaired right atrial sensing. No interference was detected in 71 patients (65%) within the tested limits with programming to maximum sensitivity, whereas 20 of 110 subjects (18%) exhibited right ventricular disturbances and 19 of 31 (61%) subjects exhibited right atrial disturbances. Conclusions— Extremely low-frequency daily-life electromagnetic fields do not disturb sensing capabilities of ICDs. However, strong 50-Hz electromagnetic fields, present in certain occupational environments, may cause inappropriate sensing, potentially leading to false detection of atrial/ventricular arrhythmic events. When the right atrial/right ventricular interferences are compared, the atrial lead is more susceptible to electromagnetic fields. Clinical Trial Registration— URL: http://clinicaltrials.gov/ct2/show/NCT01626261 . Unique identifier: NCT01626261.

In this paper, we propose a non-rigid registration method of lung parenchyma in temporal chest CT scans using region binarization modeling and locally deformable model. To cope with intensity differences between CT scans, we segment the lung vessel and parenchyma in each scan and perform binarization modeling. Then, we match them without referring any intensity information. We globally align two lung surfaces. Then, locally deformable transformation model is developed for the subsequent non-rigid registration. Subtracted quantification results after non-rigid registration are visualized by pre-defined color map. Experimental results showed that proposed registration method correctly aligned lung parenchyma in the full inspiration and expiration CT images for ten patients. Our non-rigid lung registration method may be useful for the assessment of various lung diseases by providing intuitive color-coded information of quantification results about lung parenchyma.

To present the experience of pediatric percutaneous nephrolithotomy (PCNL) of our center.This study was conducted from 1995 to 2015, on patients15 years of age having renal and upper ureteral stones who underwent PCNL. Stones were classified as per Guy's stone score (GSS). Standard bull's eye technique was used for subcostal puncture. To avoid supracostal puncture, puncture was done in full inspiration or by oblique tract. If these maneuvers failed, then supracostal puncture was done. Tract was dilated to 24F.Six hundred sixty PCNLs were performed on 639 patients. Puncture was subcostal in 87.6% cases with tract dilated as much as 24F. Pelvicaliceal system was most commonly accessed through middle calix (73.94%). Upper caliceal puncture (23.78%) was more frequently used in complete (82.35%) and partial staghorn (51%) stones. Two tracts were made in 16 (2.42%) cases, because of large stone burden. Average operative time was significantly longer in complex (45.43 minutes) compared to simple stones (29.39 minutes). Overall success rate was 94.39%, but it was significantly lower in partial (91.37%) and complete staghorn stones (82.35%). Complications were present in 21.66% cases and were classified according to Clavien grading. Majority of patients (97.9%) had minor complications (Clavien grade 12). On multivariate analysis, GSS ≥2, stone size200 mmPCNL is a minimally invasive surgical technique for removal of renal and upper ureteral stones, which have low morbidity rate, high success rate, and short hospital stay. Although the uses of smaller instruments are on the rise, procedure can still be safely performed in children using adult instruments. Supracostal approach if done cautiously does not increase morbidity rate.

The present report describes a case of successful chemoembolization via the right inferior phrenic artery (RIPA) in a patient with hepatocellular carcinoma and celiac stenosis due to the median arcuate ligament sling. The RIPA, which was not visualized on celiac angiography obtained at full expiration, was evidently visualized on angiography performed at full inspiration, followed by successful catheterization. Angiography at full inspiration can visualize and facilitate the catheterization of the RIPA in patients with celiac stenosis due to the median arcuate ligament sling.

Kirby RL, Heimrath O, Stewart A, Smith C, MacLeod DA. Effect of respiration on the static rear stability of wheelchairs. Objective To test the hypothesis that the static rear stability of an occupied wheelchair is greater during full inspiration than expiration. Design Within-subject comparisons. Setting Rehabilitation center. Participants Able-bodied participants (N=10). Intervention None. Main Outcome Measures We measured the static rear stability (brakes unlocked) of an occupied wheelchair on a test platform according to International Organization for Standardization standards. We also used the Exhalation Threshold Test. The Exhalation Threshold Test was positive if, having been positioned at the maximum degree of platform tilt needed to maintain stability during full inspiration, the wheelchair tipped backward when the participant exhaled. Results The mean static rear stability values at full inspiration and expiration ± SD were 16.5°±2.3° and 16.1°±2.4°, with a mean difference of .46°±.24° (3%; P=.002). The Exhalation Threshold Test was positive in 19 (95%) of 20 trials. Conclusions Respiration has a slight but statistically significant effect on the rear stability of occupied wheelchairs, with greater stability at full inspiration. This has potential clinical implications for stability testing and the training of wheelchair skills, but further study is needed.

The aim of this study was to evaluate the ability of experienced thoracic radiologists to assess full inspiration based on two CT slices, one above and one below the carina, in normal subjects. Ten healthy volunteers were studied. Total lung capacity (TLC) was measured with a body plethysmograph. High-resolution computed tomography (HRCT) was performed in two slices at TLC and at various expired volumes. Mean Hounsfield values (HU) were calculated. Unidentifiable images, stored on a web server, were analysed visually by experienced thoracic radiologists. The results show that the mean lung density at TLC varied by approximately 40 HU between individuals. Within an individual this may correspond to a decrease in lung volume of approximately 25% of TLC. On visual determination of images taken at 65-74% of TLC, more than one-third of the images were assessed as taken at full inspiration; of the images taken at 75-84% of TLC, approximately 50% were assessed as taken at full inspiration. We conclude that visual determination of full inspiration on CT images in normal subjects is highly inaccurate. If quantitative density measurements are to be used in the diagnosis or follow-up of lung disease, thorough control of full inspiration is recommended.

Many elderly patients in nursing homes in the United States use metered-dose inhaler (MDI) medications for a variety of lung diseases. We wondered how much the nursing support staff knew about correct MDI inhaler technique. Thirty-eight nursing home support staff were asked to demonstrate correct use of a placebo MDI inhaler on themselves. The staff completed an average of 6.9 steps out of 8 correctly. The most common error demonstrated was the staff did not hold their breath for 10 seconds at full inspiration after inhaling the medication. The results suggest that the support staff have incorrect MDI inhaler technique.

Twenty-six male swimmers (13 Blacks, 13 Whites) matched for age, weight, and stature were subjects in the comparison of anthropometric characteristics and horizontal and vertical buoyancies. Subjects were tested in a swimming pool in the horizontal position. The time necessary for the body to return to the vertical position defined horizontal buoyancy. Vertical buoyancy was the hydrostatic lift necessary to maintain the subject immersed to the nose. The results indicated similarities in arm span, trunk flexibility, and full inspiration and exhalation of Black and White subjects. However, there were differences in body fat distribution (P ≤ 0.05) and buoyancies (P ≤ 0.01), with Whites storing more fat and having better buoyancy than Blacks. Am. J. Hum. Biol. 9:87-92 © 1997 Wiley-Liss, Inc.

Chronic obstructive pulmonary disease (COPD) is a devastating disease. In this paper, we propose a novel method for scoring of air trapping in the lungs for detection and evaluation of COPD. The proposed method finds volumetric changes of the lungs from inspiration to expiration. To this end, trachea CT images at full inspiration and expiration are compared. For this comparison, the lungs parenchyma in the inspiration and expiration images are found and changes in the surface and volume of the lungs between inspiration and expiration are used to define quantitative measures (features). Using these features, the subjects are classified into two groups of normal class and COPD patients using a Bayesian classifier. In addition, t-tests are applied to evaluate discrimination powers of the features for this classification. The main advantage of the proposed method is its ability to estimate air trapping in the lungs from CT images without human intervention. The proposed method may assists radiologists in the detection of COPD as a computer aided diagnosis (CAD) system. It may also assist them with the scoring of the disease (severity of air trapping in the lungs).

SHANDLING, A.H., ET AL.: Physical Determinants of the Endocardial P Wave. Reliable atrial sensing of intrinsic P wave activity is important to ensure optimal atrial or dual chamber pacemaker function. Various physical factors (e.g., posture, respiration, exercise) may influence P wave characteristics and impair adequate sensing. To investigate this phenomenon, we measured the average of three P wave amplitudes (PWA) and calculated slew rates from telemetered printouts acquired from Pacesetter pacemakers in 32 patients. These measurements were performed in various body positions, with upright exercise and in varying stages of respiration. Results: the mean supine PWA increased on full inspiration (3.56 ± 1.3 mV versus 3.25 ± 1.2 mV during quiet respiration, p < 0.001), and also increased significantly with full expiration. The mean PWA increased on assuming the erect position (3.25 ± 1.2 mV increasing to 3.49 ± 2.3 mV, p < 0.001); in the upright position, the mean erect PWA during quiet respiration was not significantly influenced by the stage of respiration. The mean upright exercise PWA did not differ significantly from the preexercise erect PWA (3.50 f 1.2 with exercise, and 3.47 ± 1.5 before exercise; P = NS). Calculated slew rates were not different lying versus standing. Conclusions: the mean supine PWA increases significantly at the extremes of respiration and on assuming the erect body position; upright exercise results in no appreciable change in the erect PWA. Atrial sensitivity adjustments based on standard supine testing should be adequate for all body positions. (PACE, Vol. 13, December, Part I 1990)

Focused Impedance Method (FIM) provides an opportunity for localized impedance measurement down to reasonable depths within the body using surface electrodes, and has a potential application in localized lung ventilation study. This however needs assessment of normal values for healthy individuals. In this study, localized ventilation maps in terms of electrical impedance in a matrix formation around the thorax, both from the front and the back, were obtained from two normal male subjects using a modified configuration of FIM. For this the focused impedance values at full inspiration and full expiration were measured and the percentage difference with respect to the latter was used. Some of the measured values would have artefacts due to movements of the heart and the diaphragm in the relevant anatomical positions which needs to be considered with due care in any interpretation.

Background : The correlation between the high resolution computed tomography(HRCT) emphysema score and the physiologic parameters including resting and exercise pulmonary function test was investigated in 14 patients( years) with pulmonary emphysema. Methods : The patients underwent a HRCT, a resting pulmonary function test, and incremental exercise testing(cycle ergometer, 10 W/min). Computed tomography scans were obtained on a GE highlight at 10 mm intervals using 10 mm collimation, from the apex to the base after a full inspiration. The emphysema scores were determined by a CT program 'Density mask' outlining the areas with attenuation values less than -900 HU, indicating the emphysema areas, and providing an overall percentage of lung involvement by emphysema. Results : Among the resting PFT parameters, only the diffusing capacity(r=-0.75) and (r=-0.66) correlated with the emphysema score(p-pulse(r=-0.73), and the physiologic dead space ratio at the maximum workload(r=-0.80)(p

A valid and reliable technique was developed to measure the center of volume in the human body for application to activities performed in an aquatic medium such as swimming. This technique was experimented with males and females and for two lying body positions (arms extended above and below the head). The center of volume was found to be systematically higher within the body than the center of gravity. The distance between the centers and the torque were statistically smaller in females and smaller with the arms extended above the head; however, the distance between the centers was remarkably small and both factors, sex and posture, only slightly affected this variable. The comparison of two breathing states, full inspiration and full expiration, suggested that the breathing state considerably influenced the torque causing the vertical drop of the feet.

Many spirograms cannot be interpreted properly even when the technician is expert. The criteria of an interpretable spirogram are (1) full inspiration, (2) quick attainment of highest flow, (3) continuous decrease in flow with expiration, (4) smooth, gradual termination, and (5) expiration lasting three seconds or more. Violation of these criteria leads to "pseudo-obstruction" when expiration is not forceful, to "concealed obstruction" when the graphic record is started late and to two kinds of "pseudo-restriction," one due to inadequate inspiration and the other to premature termination of expiration. A "decision tree" for dealing with large volumes of spirometric data is presented.

Chest roentgenograms were taken at full inspiration (TLC) and expiration (RV) in healthy, nonsmoking and smoking, young and old subjects in the upright posture. Linear distances (D) were measured in apicodiaphragmatic and transverse thoracic directions and extensions [(DTLC − DRV)/DTLC and (DTLC − DRV)/DRV] and volumes were calculated. In the apico-diaphragmatic direction a subdivision was made into an apico-fissural (A-F) distance and a fissuro-diaphragmatic (F-D) distance by means of the minor fissure. Overall volumes at TLC were identical in the four groups but differences were present in distances, extensions and volumes above and below the fissure. Aging caused mainly an increase in D(A-F) and a decrease in D(F-D) at TLC as well as at RV, indicating hyperinflation and airtrapping of the upper zone and hypoinflation and flattening of the lower zone. Smoking caused an increase in D(F-D) at RV, indicating airtrapping in the lower zone. In both groups E(F-DR) was reduced, but in old subjects this was due to a decrease in regional TLC and in young smokers to an increase in regional RV. In old, smoking subjects a combination of the effects of aging and smoking was present.

Threshold of airway response to inhaled methacholine was determined using maximum expiratory partial flow-volume curves in 21 men and 36 women with similar age distribution, all of them healthy nonsmokers. Mean threshold was on average 1.3 doubling dose lower in women than men. There were no sex differences in the increase of maximum expiratory flows after a full inspiration when the airways were constricted by methacholine.

In 75 hospital patients an estimation of liver span was made independently by students (I), fellows (II), and consultants (III). These bedside estimates were made three times at full inspiration in a right parasagittal line one third of the sternal length from the midline by palpation, direct, and indirect percussion. These bedside estimates were compared to each other and to ultrasound in full inspiration in the supine position and to scintiscan in quiet respiration. We found that bedside estimate of liver span by direct percussion was as accurate as ultrasound, but that indirect percussion estimate of liver span was inaccurate. Scintiscanning during quiet respiration over-estimates the liver span in comparison to ultrasound. Previous suggestions that clinical estimates of liver span should be abandoned may be in error.

Respiratory movement of the pancreas was documented ultrasonically in 36 normal patients and volunteers. Pancreatic excursion from full inspiration to full expiration was measured in the plane of the superior mesenteric artery in supine, prone, and decubitus positions. Excursions ranged from 0 to 3.5 cm. The average respiratory excursion was 1.8 cm in the supine position, 1.9 cm when prone, and 2.2 cm in the lateral decubitus position. Such respiratory movement of the pancreas has obvious implications both for static B-mode ultrasound scanning and for CT scanning.

Advent of new imaging modalities such as computed tomography, magnetic resonance imaging and ultrasound contributed greately to the specific imaging diagnosis. However plain chest X-ray is still most prequently used for imaging diagnosis of respiratory disease in clinical pratic and it is important to make a good quality of X-ray film and good interpretation. The optimal chest X-ray should be taken with full inspiration without rotation and motion and the exposure is at the level of barely demonstrable thoracic vertebral disc space. It is recommended that higk KVP technique for detection of lesions which is overlaped by mediastinum, heart and rib cage. It is better to examine chest X-ray film start at some distance(6-8 feet) and closer to the film later on and the reader should not read a film in fatigue condition. The reading room should be quiet and relately dark illumination. It is important, to make a good X-ray film and good interpretation to reduce the observer error.

Several methods of importance for the study of the physiology and pathology of respiration and circulation require (1) that it is possible to produce full admixture of air within the lungs with other air and (2) that the exact conditions necessary for full mixture can be ascertained in a given case. This and the following paper is a short report of experiments dealing with questions.Technique. 3 liters of oxygen (Allen-Pepys' method) or of hydrogen plus oxygen (Davy-Durig's method) are introduced in a 5 to 6 liter rubber bag. Starting either from full inspiration or full expiration the subject rebreathes uniformly and almost as deeply as possible from the bag a certain number of times. The connection between the mouth and the bag is a 35 cm. long, 2 cm. wide rubber tube and a 3-way stopcock. The frequency of respiration has always been betwen 8 and 20, usually about 10-15 per minute. During the experiments several small samples (15-20 c. c.) of air were drawn (1) from the bag, and (2) from the very last p...

This report is based upon a personal series of nearly 200 investigations, conducted between 1962 and 1966, in which an attempt was made to widen the range and increase the accuracy of information obtainable from translateral films. It was found that the tradition of taking abdominal films only in expiration ought to be abandoned in translateral films. Films taken in full inspiration may be the only ones in which a significant measurement of the retro-gastric mid-plane diameter can be made and in which a pancreatic impression appears upon the posterior gastric wall. The view is also expressed that on the translateral film the shape and size of the tunnel visible between the gastric fundus and the duodenojejunal flexure provides a basis for the estimation of the shape and size of the body of the pancreas. It is also possible to gauge the thickness of the mesocolon and of the retroperitoneal fatty layers in most cases. By this means, suitable corrections can be made to measurements on the translateral radiographs.

It is widely accepted that a palpable spleen in the adult population is always enlarged and pathological. The aim of this study was to assess the validity of this statement. As a routine, our protocol for liver-spleen studies includes liver pliability, which demonstrates the level of the hemidiaphragms at full inspiration and expiration, as well as splenic size and colloidal uptake. Sixteen hundred 99mTc sulphur colloid liver-spleen studies, which had been performed in our Department, were reviewed. In 21 patients, who had been referred with "splenomegaly for investigation", the scintigraphic splenic size was 13 cm posterior length or less. In this group, splenic palpability was confirmed by at least two clinicians. Follow-up did not reveal any evidence of splenic disease in 18 of the 21 patients. In a separate postmortem follow-up of 123 sequential liver-spleen scans, 100 patients were noted to have a scintigraphic splenic size of 13 cm posterior length or less. This was shown to be a reliable upper limit of normal because 98% of spleens in this group weighed 250 g or less and were normal at post-mortem examination. This study demonstrates that a palpable spleen is not necessarily enlarged or pathological.

The majority of pediatric examinations performed outside a large center are likely to be chest radiographs. Even at The Hospital for Sick Children, chest radiographs account for 36% of the total department work load.

The concepts of interpretation of a chest radiograph taken on a patient in the upright position and full inspiration are different from the concepts of interpretation of the supine chest radiograph of a critically ill or injured patient.

Posteroanterior and lateral radiographs of the lungs of 30 normal adults were obtained at total lung capacity (TLC) and 1 sec after initiation of forced expiration from ttlc. simultaneous spirographic recording of the volume expired (FEV-1) and independent plethysmographic recording of TLC were obtained. Two types of measurements were made from the radiographs: 1) surface areas of the lung fields, measured planimetrically; and 2) combinations of linear distances between selected points. These radiographic measurements and the measured lung volumes were subjected to computer analysis to develop reliable formulas for determining lung volumes solely from radiographs. Formulas derived using planimetry produced multiple correlation coefficients of 0.95 for TLC and 0.89 for volume during forced expiration. Use of linear measurements produced multiple correlation coefficients of 0.92 for TLC and 0.84 for dynamic volume. Thus, in normal subjects, static lung volumes and lung volumes during dynamic forced expiration can be determined from radiographs.

A new method for the detection of enlargement of the body and tail of the pancreas is described. The technique consists of taking a lateral film of the abdomen, using a horizontal beam with the patient supine. Exposures are made in both full inspiration and full expiration. This method is particularly useful in cases of inflammatory disease of the pancreas.

Disorders of the pleural space or of the thoracic skeleton impair full expansion of the lungs by attenuating the force generated by the inspiratory muscles. (Conditions where the muscles themselves are weak are considered in chapter 13.) All these are potential extrapulmonary causes of volume restriction. In each case the lungs themselves frequently show secondary functional abnormalities: the effects of lung compression by a distorted thoracic cage, of micro-atelectasis owing to lack of the ‘good stretch’ given by a periodic full inspiration, or of mismatching of ventilation and perfusion, therefore, often contribute to the results of conventional tests. In general the integrity of the alveolar-capillary membrane is retained but the impairment of full expansion of the lung may lead to some reduction of the CO Diffusing Capacity and to a KCO which is typically high normal or frankly increased (see section 3.2).

During the past 8 yr over 170 patients in the Glasgow area have received cardiac pacemaker implants. All such patients attend pacemaker clinics at which both clinical and electronic examinations are carried out. The Pacemaker Frontal Plane Vector technique developed in Glasgow has enabled many changes in pacing function to be detected, often before clinical symptoms appear. Hitherto, measurements have been made using a calibrated differential oscilloscope: the Pacemaker Digital Electrocardiographic described in this paper offers improved accuracy in the measurement of the pacemaker frontal plane vector thus enabling further development of the above technique. The instrument also measures pacemaker pulse width and rate with an accuracy of ±0·1 per cent which should be sufficient to detect ageing of the newer Medtronic ‘rate-stable’ generators (type 5862—fixed rate and type 5842—QRS blocking).

THE FORCED expiratory volume (F.E.V.), or volume of air expired during a forced expiration from full inspiration in usually 0.75 or 1 second, is widely accepted as a useful measure of ventilatory capacity. Two types of apparatus are in common use for its measurement. The recording spirometer with the fast-moving kymograph has the advantage of providing a permanent record which can later be analysed in various ways.1, 2The simple spirometer with electronic timer described originally by Gaensler3and modified by McKerrow et al.4shows the volume of air expired in a preset time period by a pointer indicating on a scale on the spirometer wheel. The advantages of this type of machine are its greater portability, ease of use, and the provision of the reading immediately without the necessity of analysing a record—features which make it especially valuable for routine clinical use and in field

To the Editor: —Permit me to vouchsafe a bit of valuable information for the benefit of your readers in regard to Kuhn's aspiration mask. It may not be generally known that all the beneficial results of the mask can be secured in a much simpler manner by using a section of a small catheter, about No. 16F, or a straw or quill to draw the breath through, thus retarding inhalation quite as effectually as by use of the cumbersome mask; but such is the case. The only benefit of the mask is to insure a deep, full inspiration of air slowly and gradually, holding it a few seconds and then its sudden expiration, which, as you remark (The Journal, Feb. 22, 1913, p. 632), produces negative compression of the lungs, sucking the blood from the right chamber of the heart into the lungs. When the heart is weakened and tired

1. 1. A group of 20 normal subjects and 24 patients with coronary heart disease were studied on a head-foot ultralow-frequency ballistocardiograph in both a resting and postexercise condition. Measurements of features of their accurately calibrated ballistocardiograms were made. 2. 2. With the aid of automatic data processing methods, several of these measurements which showed significant differences between the normal and cardiac groups were identified. These measurements were combined in a discriminant analysis which classified 75 per cent of the whole group correctly. 3. 3. This figure appears to be somewhat better than that from other ballistocardiographic studies employing the more subjective waveform-reading technique. Analysis of the results suggests changes in exercise technique and record-measurement procedure which promise ultimately greater accuracy in discrimination. 4. 4. The study also showed that the best features for discriminating coronary heart disease were found in full inspiration, and that the accelaration slopes (“jerk”) in early systole were among the strongest features.

As the clinical value of determinations of the vital capacity of the lungs becomes more clearly emphasized — in heart disease, in tuberculosis, in aeronautics, etc.—the problem of normal standards becomes increasingly important. For the clinician, the standard should require as few and simple measurements as are consistent with reasonable accuracy. Since the earlier studies on this subject, it has been recognized that healthy individuals vary considerably in the volume of air which they can expire after a full inspiration. Age, sex, height, weight, the size and flexibility of the chest, muscular strength and physical training are factors which may singly or jointly affect the vital capacity. As an example, trained soldiers, and especially athletes, tend to show higher vital capacity readings than clerks of the same age, height and weight. The probability, therefore, of finding a single standard for all classes of individuals that does not involve numerous measurements

Misinterpretation of the diaphragmatic crura on axial computed tomography images is a recognized pitfall in diagnosis. The right diaphragmatic crus is generally longer and thicker than the left. The authors observed a case in which the left crus was thicker than the right, causing diagnostic difficulty. Obtaining scans at full expiration and full inspiration clarified the situation. Confirmation of respiratory variation in crural thickness was obtained in ten patients. The crura increased in thickness on inspiration, compared with the size on expiration.

These three cases of non-opaque foreign body inhalation in children are reported as a reminder that a chest film taken in full inspiration may be misleading, and to demonstrate the necessity of screening these cases with exposure of films in both inspiration and expiration in order that a non-opaque foreign body in a bronchus may be diagnosed and localised.

The respiratory ratio which I wish to describe is obtained as follows: The patient is told to take a deep breath and to hold it as long as he can. He is further instructed to raise his hand when he feels that he must expire. Some little time (five minutes) is then spent in the ordinary examination; then the patient is told to expire fully and not to breathe in till he is compelled to do so, when he again must raise his hand. The time from the beginning of either of these phases of respiration to the time of raising the hand is noted and the ratio thus obtained. The period during which the breath has been held in full inspiration by healthy individuals has varied from 40 to 70 seconds. The period during which the breath has been held in full expiration in the same individuals has varied

Since infants cannot cooperate, the apparatus shown in figure 1 was devised to determine their vital capacity. It consists of a 5 gallon (22.7 liter) closed container, similar to a milk can, of sufficiently heavy gage metal so that the walls are rigid. A water manometer is connected to measure the pressure within the container, which is connected by heavy walled rubber tubing with a Marriott face mask. 1 The container is calibrated by pouring measured amounts of water into it. As shown in figure 2, the pressure increases 1 mm. for each 4.8 cc. of water added to the container, or 0.23 mm. per cubic centimeter. The vital capacity of an infant is measured by placing the face mask quickly and tightly over his mouth and nose at the end of a full inspiration. The maximum of several determinations is taken as the vital capacity. If the infant draws