Quantification of regional V/Q ratios in humans by use of PET. II. Procedure and normal values

1989 ◽  
Vol 66 (4) ◽  
pp. 1905-1913 ◽  
Author(s):  
C. G. Rhodes ◽  
S. O. Valind ◽  
L. H. Brudin ◽  
P. E. Wollmer ◽  
T. Jones ◽  
...  
Keyword(s):  
Left Lung ◽  
Normal Subjects ◽  
Slice Thickness ◽  
Dependent Lung ◽  
Quiet Breathing ◽  
Mean Values ◽  
Positron Emission ◽  
Supine Posture ◽  
Quantitative Manner ◽  
The Right

Regional measurements of tissue isotope concentration, made using positron emission tomography (PET), allow tracer models to be used in a quantitative manner to provide topographic distributions of many structural and functional parameters, each derived for the same well-defined lung element. In this paper we describe a technique to measure regional ventilation-perfusion ratios (V/Q), in absolute units, by use of PET and the continuous intravenous infusion of an inert gas isotope, 13N, and report on measurements made in 12 normal subjects (4 smokers). Data were obtained from a single lung section (slice thickness, 1.7 cm full width at half-maximum response to a line source) at the level of the right ventricle in the supine posture during quiet breathing. For the 12 subjects, volume-weighted mean values of V/Q, averaged over individual right and left lung fields, ranged from 0.50 to 1.29. Analysis of these means showed no difference between lungs: right, 0.80 +/- 0.23 SD; left, 0.76 +/- 0.20 SD. Topographically, a systematic fall of V/Q in the ventrodorsal direction was observed in eight of the subjects (mean ventrodorsal difference 0.39, range 0.19–0.90), whereas two showed a clear increase toward dependent lung regions (range 0.16–0.26). Seven of the subjects with a falling ventrodorsal V/Q gradient also exhibited discrete regions of low V/Q at the dorsal lung border. We conclude that, in normal subjects, ventilation and perfusion are generally well matched in the supine posture, but isolated mismatching often occurs in dependent lung regions.

Interrelationships between regional blood flow, blood volume, and ventilation in supine humans

1994 ◽  
Vol 76 (3) ◽  
pp. 1205-1210 ◽  
Author(s):  
L. H. Brudin ◽  
C. G. Rhodes ◽  
S. O. Valind ◽  
T. Jones ◽  
J. M. Hughes
Keyword(s):  
Blood Flow ◽  
Blood Volume ◽  
Regional Blood Flow ◽  
Left Lung ◽  
Local Variation ◽  
Normal Subjects ◽  
Horizontal Gradient ◽  
Quiet Breathing ◽  
Positron Emission ◽  
Gravitational Gradients

Positron emission tomography was used to measure alveolar gas volume, pulmonary blood volume (VB), regional alveolar ventilation (VA), and the regional ventilation-to-perfusion ratio (VA/Q) in a transaxial slice at midheart level in eight supine subjects and one prone normal subject during quiet breathing. These relationships allow regional blood flow (Q) to be calculated as VA/(VA/Q). No significant differences between right and left lung were found. Within the volume studied, which excluded the peripheral 2 cm of the lung, there was an exponential increase in Q by 11%/cm from 1.2 ml.min-1.cm-3 in the upper (ventral) to 3.5 ml.min-1.cm-3 in the lower (dorsal) lung regions, explaining 61% of the total variation within groups, whereas the horizontal gradient only explained 7% (right lung; supine subjects). Similar gravitational gradients were found in the single prone subject. VA and Q were well matched except at the dorsal lung thoracic border where low values of VA/Q due to a reduction in ventilation were occasionally found even in these normal subjects. VB and Q were reasonably well matched, implying that variations in vascular transit time due to gravity are kept to a minimum. The coefficient of local variation of peripheral vascular transit times (VB/Q) (33%) was, therefore, less than would have been expected if VB and Q were uncorrelated (57%).

Regional lung density and blood volume in nonsmoking and smoking subjects measured by PET

1987 ◽  
Vol 63 (4) ◽  
pp. 1324-1334 ◽  
Author(s):  
L. H. Brudin ◽  
C. G. Rhodes ◽  
S. O. Valind ◽  
P. Wollmer ◽  
J. M. Hughes
Keyword(s):  
Blood Volume ◽  
Left Lung ◽  
Tidal Breathing ◽  
Alveolar Volume ◽  
Lung Density ◽  
Mean Values ◽  
Positron Emission ◽  
Significant Difference ◽  
Regional Lung ◽  
The Right

Regional lung density (DL) and regional fractional pulmonary blood volume (VB) were measured quantitatively during tidal breathing in 30 healthy supine subjects (15 smokers and 15 nonsmokers) in a 1.7-cm-thick midthoracic cross section using positron emission tomography (PET) and 11CO (inhaled)-labeled erythrocytes. Regional alveolar volume (VA), extravascular lung density (DEV), and relative alveolar size (Valv = VA/DEV) were calculated. For the nonsmokers, mean values (+/- SD between subjects) for the right lung were as follows: DL, 0.28 +/- 0.03 g/cm3; DEV, 0.10 +/- 0.02 g/cm3; and Valv, 7.1 +/- 1.9 ml/g lung tissue. In the smoking subjects DEV (right plus left lung) was 16% higher. No significant difference in VB between smokers and nonsmokers was found. The differences in DEV and VB between right and left lung were not significant. Mean values (+/- SD) of the dorsal-to-ventral ratios calculated for the right lung in the nonsmokers were as follows: DL, 1.34 +/- 0.16; VA, 0.90 +/- 0.05; VB, 1.52 +/- 0.26; DEV, 1.10 +/- 0.17; and Valv, 0.85 +/- 0.19. Almost identical ratios were found in the smokers. The influence of overall thoracic expansion was investigated in one subject restudied during voluntary hyperinflation and during positive end-expiratory pressure.

Regional Lung Function in Bilateral Diaphragmatic Paralysis

1980 ◽  
Vol 59 (6) ◽  
pp. 485-492 ◽  
Author(s):  
T. C. Amis ◽  
G. Ciofetta ◽  
J. M. B. Hughes ◽  
L. Loh
Keyword(s):  
Normal Subjects ◽  
Diaphragmatic Paralysis ◽  
Upright Posture ◽  
Alveolar Volume ◽  
Supine Posture ◽  
Regional Lung Function ◽  
Lower Lung ◽  
Lateral Decubitus ◽  
The Right ◽  
The Vertical Distribution

1. The distribution of regional function in the lungs of six patients with bilateral diaphragmatic paralysis was investigated by continuous inhalation and infusion of the radioactive gases 81mKr and 85mKr during tidal breathing. 2. In the supine and right lateral decubitus postures the vertical distribution of ventilation per unit alveolar volume was less in the dependent zones, the reverse of that found in normal subjects. In the upright posture ventilation was slightly decreased at the lung base. Perfusion per unit alveolar volume was more uniformly distributed than normally in the upright posture, and decreased from superior to inferior in the supine posture. In the lateral decubitus posture, perfusion of the lower lung was greater than that of the upper. Ventilation/perfusion ratios were more uniformly distributed in the patients than in normal subjects, except in the right lateral decubitus posture. 3. Alterations in the distribution of ventilation may be explained in terms of the altered mechanical interaction of chest wall, mediastinal and abdominal contents, with selective use of intercostal and accessory muscles. The effects on the distribution of blood flow are probably related to the low end-expiratory lung volume.

Relationships between regional ventilation and vascular and extravascular volume in supine humans

1994 ◽  
Vol 76 (3) ◽  
pp. 1195-1204 ◽  
Author(s):  
L. H. Brudin ◽  
C. G. Rhodes ◽  
S. O. Valind ◽  
T. Jones ◽  
B. Jonson ◽  
...  
Keyword(s):  
Left Lung ◽  
Vertical Direction ◽  
Vertical Gradient ◽  
Quiet Breathing ◽  
Alveolar Volume ◽  
Positron Emission ◽  
Significant Linear Correlation ◽  
Horizontal Variation ◽  
Gravitational Gradients ◽  
Extravascular Volume

With the use of positron emission tomography, alveolar ventilation (VA), lung density, and pulmonary blood volume (VB) were measured regionally in eight nonsmokers in the supine posture and one nonsmoker in the prone posture during quiet breathing in a transaxial thoracic section at midheart level. Regional values of alveolar volume (VA) and extravascular tissue volume (VEV) were derived from the inherent relationships between different compartments in the lung. Ratios proportional to gas volume (VA/VEV) and ventilation (VA/VEV) per alveolar unit, respectively, were calculated. No differences between right and left lung were found. Variations in the vertical direction could explain approximately 65% of the total within-group variation in VA, VB, and ln (VA), whereas the corresponding value for horizontal variation was only 3–9% (right lung, supine subjects). Similar gravitational gradients were found in the single prone subject. There was a significant linear correlation between VA and ln (VA). When VA and VA are related to a given number of alveolar units (VEV), the data are consistent with a linear relationship between VA/VEV and VA/VEV, indicating that ventilation might be explained by the elastic properties of lung tissue according to Salazar and Knowles (J. Appl. Physiol. 19: 97–104, 1964). Regional VB was closely associated with the gradient of regional alveolar volume (VA/VEV) (by virtue of weight of blood and competition for space) and therefore, indirectly, closely associated with the vertical gradient of ventilation.

scholarly journals Metastatic pulmonary adenocarcinoma to the nasopharynx at first clinical presentation: A case report and review of literature

2020 ◽  
Vol 8 ◽  
pp. 2050313X2093982
Author(s):  
Shahad Iqneibi ◽  
Jamil Nazzal ◽  
Runa Amoudi ◽  
Basma Owda ◽  
Akram Al-Ibraheem ◽  
...  
Keyword(s):  
Left Lung ◽  
Cancer Control ◽  
Metastatic Carcinoma ◽  
Pulmonary Adenocarcinoma ◽  
Review Of Literature ◽  
Thyroid Transcription Factor 1 ◽  
Positron Emission ◽  
Recurrent Epistaxis ◽  
Poorly Differentiated ◽  
The Right

Metastatic carcinomas in the nasopharynx are a rarity. We report a case of a 54-year-old male patient who presented with a history of recurrent epistaxis. On evaluation, a mass in the right Rosenmüller fossa was detected, which was biopsied and diagnosed as a poorly differentiated adenocarcinoma, immunoreactive for thyroid transcription factor-1, consistent with metastatic pulmonary adenocarcinoma. Fluorodeoxyglucose–positron emission tomography/computed tomography (FDG-PET/CT) scan confirmed the presence of a mass in the upper lobe of the left lung, proven pathologically to be a poorly differentiated pulmonary adenocarcinoma, with an immunoprofile similar to the nasopharyngeal tumor. The patient underwent palliative chemotherapy, and was then shifted to immunotherapy. He is currently alive and disease free 50 months after the initial diagnosis was made. The unusual presentation of a metastatic carcinoma in the nasopharynx will be discussed, along with a review of literature. The role of immunotherapy in cancer control and greater longevity will also be presented.

Knowing Where Things Are: Parahippocampal Involvement in Encoding Object Locations in Virtual Large-Scale Space

1998 ◽  
Vol 10 (1) ◽  
pp. 61-76 ◽  
Author(s):  
E. A. Maguire ◽  
C. D. Frith ◽  
N. Burgess ◽  
J. G. Donnett ◽  
J. O'Keefe
Keyword(s):  
Medial Temporal Lobe ◽  
Large Scale ◽  
Critical Factor ◽  
Normal Subjects ◽  
Scale Space ◽  
Parahippocampal Gyrus ◽  
Environmental Learning ◽  
Object Locations ◽  
Positron Emission ◽  
The Right

The involvement of the medial temporal-lobe region in allocentric mapping of the environment has been observed in human lesion and functional imaging work. Cognitive models of environmental learning ascribe a key role to salient landmarks in representing large-scale space. In the present experiments we examined the neural substrates of the topographical memory acquisition process when environmental landmarks were more specifically identifiable. Using positron emission tomography (PET), we measured regional cerebral blood flow changes while normal subjects explored and learned in a virtual reality environment. One experiment involved an environment containing salient objects and textures that could be used to discriminate different rooms. Another experiment involved a plain empty environment in which rooms were distinguishable only by their shape. Learning in both cases activated a network of bilateral occipital, medial parietal, and occipito-temporal regions. The presence of salient objects and textures in an environment additionally resulted in increased activity in the right parahippocampal gyrus. This region was not activated during exploration of the empty environment. These findings suggest that encoding of salient objects into a representation of large-scale space is a critical factor in instigating parahippocampal involvement in topographical memory formation in humans and accords with previous studies implicating parahippocampal areas in the encoding of object location.

Functional Anatomy of Perceptual and Semantic Processing for Odors

1999 ◽  
Vol 11 (1) ◽  
pp. 94-109 ◽  
Author(s):  
Jean-P. Royet ◽  
Olivier Koenig ◽  
Marie-C. Gregoire ◽  
Luc Cinotti ◽  
Frank Lavenne ◽  
...  
Keyword(s):  
Semantic Processing ◽  
Inferior Frontal Gyrus ◽  
Functional Anatomy ◽  
Normal Subjects ◽  
Anterior Cingulate ◽  
Perceptual Condition ◽  
Semantic Level ◽  
Positron Emission ◽  
Visual Areas ◽  
The Right

The functional anatomy of perceptual and semantic processings for odors was studied using positron emission tomography (PET). The first experiment was a pretest in which 71 normal subjects were asked to rate 185 odorants in terms of intensity, familiarity, hedonicity, and comestibility and to name the odorants. This pretest was necessary to select the most appropriate stimuli for the different cognitive tasks of the second experiment. The second one was a PET experiment in which 15 normal subjects were scanned using the water bolus method to measure regional cerebral blood flow (rCBF) during the performance in three conditions. In the first (perceptual) condition, subjects were asked to judge whether an odor was familiar or not. In the second (semantic) condition, subjects had to decide whether an odor corresponded to a comestible item or not. In the third (detection) condition, subjects had to judge whether the perceived stimulus was made of an odor or was just air. It was hypothetized that the three tasks were hierarchically organized from a superficial detection level to a deep semantic level. Odorants were presented with an air-flow olfactometer, which allowed the stimulations to be synchronized with breathing. Subtraction of activation images obtained between familiarity and control judgments revealed that familiarity judgments were mainly associated with the activity of the right orbito-frontal area, the subcallosal gyrus, the left inferior frontal gyrus, the left superior frontal gyrus, and the anterior cingulate (Brodmann's areas 11, 25, 47, 9, and 32, respectively). The comestibility minus familiarity comparison showed that comestibility judgments selectively activated the primary visual areas. In contrast, a decrease in rCBF was observed in these same visual areas for familiarity judgments and in the orbitofrontal area for comestibility judgments. These results suggest that orbito-frontal and visual regions interact in odor processing in a complementary way, depending on the task requirements.

scholarly journals Ultrasound Assessment of Diaphragm Thickness and Thickening: Reference Values and Limits of Normality When in a Seated Position

2021 ◽  
Vol 8 ◽  
Author(s):  
Alain Boussuges ◽  
Sarah Rives ◽  
Julie Finance ◽  
Guillaume Chaumet ◽  
Nicolas Vallée ◽  
...  
Keyword(s):  
Healthy Volunteers ◽  
Normal Values ◽  
Deep Breathing ◽  
Diaphragm Thickness ◽  
Quiet Breathing ◽  
Men And Women ◽  
Mean Values ◽  
Diaphragmatic Function ◽  
The Mean ◽  
The Right

Background: Diagnosing diaphragm dysfunction in the absence of complete paralysis remains difficult. The aim of the present study was to assess the normal values of the thickness and the inspiratory thickening of both hemidiaphragms as measured by ultrasonography in healthy volunteers while in a seated position.Methods: Healthy volunteers with a normal pulmonary function test were recruited. The diaphragmatic thickness was measured on both sides at the zone of apposition of the diaphragm to the rib cage during quiet breathing at end-expiration, end-inspiration, and after maximal inspiration. The thickening ratio, the thickening fraction, and the thickness at end-inspiration divided by the thickness at deep breathing were determined. The mean values and the lower and upper limits of normal were determined for men and women.Results: 200 healthy volunteers (100 men and 100 women) were included in the study. The statistical analysis revealed that women had a thinner hemidiaphragm than men on both sides and at the various breathing times studied. The lower limit of normality of the diaphragm thickness measured at end-expiration was estimated to be 1.3 mm in men and 1.1 mm in women, on both sides. The thickening fraction did not differ significantly between men and women. In men, it ranged from 60 to 260% on the left side and from 57 to 200% on the right side. In women, it ranged from 58 to 264% on the left side and from 60 to 229% on the right side. The lower limits of normality of the thickening fraction were determined to be 40 and 39% in men and 39 and 48% in women for the right and left hemidiaphragms, respectively. The upper limit for normal of the mean of both sides of the ratio thickness at end-inspiration divided by the thickness at deep breathing was determined to be 0.78 in women and 0.79 in men.Conclusion: The normal values of thickness and the indexes of diaphragmatic function should help clinicians with detecting diaphragm atrophy and dysfunction.

Lung epithelial permeability to aerosolized solutes: relation to position

1987 ◽  
Vol 62 (3) ◽  
pp. 902-911 ◽  
Author(s):  
M. Meignan ◽  
J. Rosso ◽  
R. Robert
Keyword(s):  
Left Lung ◽  
Normal Subjects ◽  
Aerosol Deposition ◽  
Gravity Gradient ◽  
Epithelial Permeability ◽  
Alveolar Volume ◽  
Lung Epithelial ◽  
Lateral Decubitus ◽  
Lung Epithelial Permeability ◽  
The Right

The lung epithelial permeability to inhaled solutes is primarily attributed to the degree of distension of the interepithelial junctions and thus of the alveolar volume. To assess this hypothesis, a submicronic aerosol of technetium-99m-labeled diethylenetriamine pentaacetate (99mTc-DTPA) was inhaled by eight normal subjects in left lateral decubitus (LLD). The regional lung clearance of 99mTc-DTPA was measured in LLD, then in right lateral decubitus (RLD) to reverse the relative distension of the alveoli. Although in LLD the deposition of the aerosol is the greatest in the gravity-dependent regions of the left lung, their 99mTc-DTPA clearances are significantly lower than those of the nondependent regions of the right lung (0.7 +/- 0.3 vs. 2 +/- 0.8%/min, P less than 0.001). In RLD, these regions placed in opposite positions significantly reversed their clearances (1.6 +/- 0.8 vs. 0.6 +/- 0.2%/min, P less than 0.001). Results indicate in lateral decubitus a gravity gradient of 99mTc-DTPA clearances independent of the aerosol deposition. This gradient of epithelial permeability to solutes appears to be influenced by the gradient of alveolar volume.

An Unusual Case of Three Synchronous Tumors in a Young Woman

2005 ◽  
Vol 91 (3) ◽  
pp. 267-269 ◽  
Author(s):  
Raffaele Longo ◽  
Guido Carillio ◽  
Antonietta Torrisi ◽  
Maria Pia Tocco ◽  
Giovanni Battista Grassi ◽  
...  
Keyword(s):  
Left Lung ◽  
Wide Resection ◽  
Clear Correlation ◽  
Caucasian Woman ◽  
Synchronous Tumors ◽  
Sclerosing Hemangioma ◽  
Positron Emission ◽  
Chest X Ray ◽  
The Right

The occurrence in the same young patient of three synchronous tumors deriving from different embryogenic tissues and without a clear correlation with a common etiopathogenic factor is very unusual. We report a case of a Caucasian woman submitted to wide resection of a large retroperitoneal liposarcoma and right radical nephrectomy for suspected tumor infiltration. Histological examination of the right ureter and renal pelvis showed the presence of a multifocal urothelial carcinoma that was clinically asymptomatic. Two months later, during follow-up, chest X-ray and computed tomography documented a coin lesion of the upper left lung, confirmed by positron emission tomography. This nodule was surgically removed and examined histologically, resulting in a diagnosis of sclerosing hemangioma. The patient is alive without evidence of recurrent disease.

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