Radiodiagnosis

Radiodiagnosis, the recognition of diseases by means of X-rays. In each specific case, R. primarily sets itself the task of resolving four fundamental questions of diagnosis: 1) whether this person has a disease (e.g. tuberculosis of the lungs) or the organ examined with X-rays is normal (so-called establishing R.); 2) what is the location of the pathological process, the degree of its development and spread, for example how many tuberculous foci there are and how much lung tissue is occupied by them, which parts are affected (quantitative R.); 3) what are the phase, form, and stages of the disease, for example what is the nature and character of the tuberculous foci (qualitative R.), and finally 4) whether there are complications of the main disease _f for example whether there are cavities, shrinkage, pleural changes in pulmonary tuberculosis (R. of complications). Modern radiology, however, cannot and should not be limited solely to the recognition of diseases. In this regard, the term "radiodiagnosis" is too narrow and does not reveal all the content of this main branch of radiology, and should be replaced by the expression "radiological examination." Radiological examination covers the comprehensive study not only of the pathological but also of the normal human organism and is a most valuable method for observing the development and course of various normal and pathological processes. This constitutes one of the greatest fundamental advantages of radiology over normal and pathological anatomy, which is forced to study dynamic phenomena by comparing fragments of individual phases from the overall picture of evolution from different individuals. The main methods of radiological examination are fluoroscopy and radiography. Fluoroscopy (transillumination, radioscopy, skiaskopy, fluoroscopy) is the obtaining of a shadow image on a glowing in the dark fluorescent (translucent) screen, while radiography (radiography, skiagraphy, actinography) is the obtaining of a shadow X-ray picture on a light-sensitive photographic emulsion on film or glass, i.e. obtaining an X-ray photograph (radiogram, skiagram, etc.). Fluoroscopy is a simpler, more accessible, faster, and cheaper method of examination. It is necessary for examining movable organs and motor phenomena (heart contractions, respiratory excursions of the diaphragm, peristalsis of the stomach, etc.), it is irreplaceable for examining the patient in various oblique and inclined positions, for all kinds of combined methods of examination under screen control, such as for the method of X-ray palpation, determination of tender points, insertion of probes, endoscopy under the guidance of transillumination, introduction of some contrast media, such as insufflation of the large intestine with air, etc. In contrast to transillumination, radiography has the advantages of revealing the finest details of the structural pattern visible on the screen; the radiograph as a permanent object possesses greater documentary and probative force. For the purposes of comparison and correlation in repeated radiological examinations and for observing the evolution of processes, for scientific research and pedagogical work, series of X-ray photographs are in turn irreplaceable. Fluoroscopy and radiography complement each other. Thus, for example, a complete examination of the lungs consists of transillumination and radiograph, the main method of radiological examination of the heart and large vessels is fluoroscopy, of bones - radiography, and for the examination of each organ or system of organs, an optimal "tactics" {Berg} has been developed in practice, i.e. methodology and technique of examination (see respective organs). More specialized methods of radiological examination are orthodiagraphy, teleroentgenography and teleroentgenoscopy, stereoradiography and stereoroentgenoscopy, roentgenokinematography, serial radiography, roentgenokymography, etc. Orthodiagraphy is used to determine the true size and shape of the shadow silhouette, most often of the heart and large vessels. The outer contours of the organ are outlined by the central X-ray beam, i.e. a beam perpendicular to the plane of the screen, and individual points are fixed on paper by some recording method (writing instrument, puncturing with a needle, burning with an electric spark, etc.). The orthodiagram thus eliminates the distortion of the X-ray image of the object which under ordinary conditions of transillumination is inevitably caused by the divergent beam of rays. The same goal is pursued by teleroentgenography and roentgenoscopy when the tube is moved away from the patient to a distance of 1.5-2-4m, and the examination is performed with practically a parallel beam of rays. The results of the orthodiagram, teleroentgenogram, and sketches from the screen in teleroentgenoscopy are generally the same; the teleroentgenogram is the most objective, the orthodiagram is the most accessible and practical, while the sketch of the shadow image at a distance is the least accurate. Stereoradiography is a method of spatial, three-dimensional analysis of two X-ray images, viewed by means of stereoscopic glasses or mirrors. These two X-ray photographs are taken of a stationary object by means of shifting the focus of the anti-cathode of the tube in a direction parallel to the film at an average distance of 6-7 cm, i.e. the distance between the pupils. Stereoroentgenoscopy - the corresponding method of transillumination - still represents a technically insufficiently resolved problem. Great technical difficulties are also presented by roentgenokinematography. Existing models of apparatus for the automatic production of several dozen photographs per second from a moving organ have not yet become common in X-ray departments. Instead, the method of targeted and serial radiography has found wide practical application, i.e. the production with the help of special apparatus of a series of centered partial photographs of small sizes of details revealed on the screen during transillumination, mainly of the stomach and duodenum. The method of roentgenokymography has very limited significance, i.e. the recording on an X-ray photograph of the amplitude and character of various contractions (pulsatory, tonic, peristaltic, respiratory, etc.). The kymogram is produced by radiography of the contracting object, e.g. the heart, through a slit in a lead plate placed perpendicular to the surface contour of the object or, in other words, parallel to the direction of contraction. As is known, the penetrating property of X-rays depends on a number of factors, among which the main ones are the quality of the rays (their hardness or softness), the thickness of the object, its density (specific weight) and atomic weight (ordinal number in the periodic table of elements). Only a differentiated shadow picture can be subjected to radiological analysis, i.e. the total image of more or less intense areas. On the radiograph, only what is contrast is visible, what stands out by illumination on a dark background or ^-by darkening on a light background. That is why on a radiograph of the chest, in rough outline, shadows of three gradations of density are obtained, namely - the most dense shadows of the bony elements, less intense, merging with each other - the shadows of the so-called soft tissues (muscles, fatty tissue, skin, blood vessels, nerves, etc.) and the most transparent shadows of the lung tissue containing air. That is why, on the other hand, a tumor of the abdominal cavity or brain, since it does not contain calcium deposits, under ordinary conditions of radiological examination cannot be distinguished from the surrounding soft tissues and consequently cannot be directly recognized. For the same reason, such different in nature pathological products in the pleural cavity, for example exudate and transudate, pure blood, serous, purulent and hemorrhagic fluid, fibrin, connective tissue adhesions, tumor masses, etc., which do not differ significantly from each other in specific and atomic weight, cannot be differentiated radiologically by their darkening. Thus, for radiological examination of some organs (bones, heart, lungs), natural conditions of contrast are present, while other organs can become an object of R. only on the condition of creating artificial contrasts. For this purpose, there are very diverse paths. Such is first of all probing under screen control of the esophagus, fistulous tracts, ureters, etc. with the help of probes impermeable to X-rays. Next follows a series of radiodiagnostic methods for determining hollow organs by introducing contrast media with a low ordinal number, i.e. air or harmless gases.

This includes the method of inflating joint cavities, inflating the large intestine, the bladder (pneumocystourethrography), and the renal pelves (pneumopyelography), diagnostic pneumothorax, pneumopericardium, and pneumoperitoneum, pneumorenography of the kidneys and adrenal glands (pneumoren) by introducing air into the perirenal bed, and finally encephalography (contrast X-ray examination of the brain and its membranes by replacing the cerebrospinal fluid with air introduced through a lumbar or suboccipital puncture) and ventriculography (the same through direct puncture of the lateral ventricle of the brain). There are even more numerous methods of X-ray examination using contrast media with high atomic numbers. It goes without saying that the contrast substance must be non-toxic, without harmful side effects, and as indifferent as possible. Such properties are possessed by chemically pure bismuth carbonate (Bismutum carbonicum purissimum pro usu interno) and the cheaper, perfectly purified barium sulfate (Barium sulfuricum purissimum pro usu interno roentgenologico), which has replaced it and is widely used for examining the gastrointestinal tract. Barium is taken orally in the form of a suspension in water or milk, in capsules (see), in the form of a paste mixed with porridge, jelly, puree, as well as in special preparations such as tachibarium, reibarit, rentium, etc. This contrast method forms the basis of modern, extensive radiodiagnosis of the esophagus, stomach, duodenum, small and large intestine. The large intestine can also be made visible by X-ray through the method of contrast enema (irrigoscopy), developed in many modifications. Salts of bismuth and barium are also used in suspension in various oils, mainly in vaseline, for filling fistulas in various diseases and their complications (e.g., cold abscesses, empyemas, osteomyelitis, foreign bodies for impregnating the latter, etc.). Special development has been given to methods of contrast X-ray examination after the introduction into practice of the French preparation lipiodol (see), which is highly contrasting, relatively stable, a compound of poppy oil with iodine, which, despite its high concentration (0.54 g of pure iodine per 1 g of oil), is chemically and pharmacologically inactive. Thanks to lipiodol and its German analog iodipin, it became possible to perform contrast examination of the paranasal sinuses, especially the maxillary and frontal sinuses, the lacrimal pathways, and the salivary ducts (sialography). Bronchography, hysterosalpingography (hysterography, uterography, salpingography), and myelography have gained practical application in the clinic. Lipiodol can also be introduced into the spinal cavity itself in the spinal cord (in syringomyelia)—the method of endomyelography, as well as along the course of nerve roots and trunks—the method of epidural and peripheral neuroraphy. Methods of introducing contrast media (lipiodol, collargol, halide salts—sodium and potassium bromide and iodide, etc.) into the hollow urinary organs—urography, pyelography, ureterography, cystography, urethrography, as well as into certain parts of the male genital organs—the seminal ducts, the seminal vesicles (vesiculography)—have been highly detailed. Methods of contrasting peripheral blood vessels—arteries and veins—are in the stage of perfection: the methods of angiography, arteriography, and phlebography, in particular the examination of cerebral arteries—the so-called arterial encephalography. The lymphatic vessels and nodes of a living person have not yet been made visible by X-ray. On a different principle, namely the ability of certain organs to selectively excrete specific contrast salts, is based the contrast X-ray examination of the gallbladder (cholecystography) and again the urinary organs (the so-called intravenous urography). A special preparation (tetraiodophenolphthalein sodium, tetrabromophenolphthalein sodium, tetragnost, kerazol, iodekon, etc.), consisting of phenolphthalein linked with a contrasting halogen (iodine, bromine), introduced into the body by any route (intravenously, orally, rectally, through a duodenal tube), is excreted by liver cells into the bile ducts and, under normal conditions, enters the gallbladder, where the contrast salt concentrates and makes the bladder visible on the X-ray. Intravenous urography, which successfully replaces retrograde urography in certain indications, is based on the ability of renal epithelium to selectively excrete urea and its compounds. For this purpose, preparations such as abrodil, prabrodil,uroselectan, iopax, our Soviet preparation sergozin, and others are used. Even more original is the principle of artificial contrasting of certain organs by introducing substances that are selectively absorbed and bound by these organs or systems of organs. Such is the method of examining the reticuloendothelial system, primarily the liver (hepatography) and spleen (liengraphy) by intravenous introduction of thorotrast, the main component of which is thorium dioxide. Attempts are being made in a similar direction to make the brain accessible to X-ray examination. Radiodiagnosis, while remaining an independent medical discipline, occupies an intermediate position between anatomy and clinic. X-rays should serve as a conductor of anatomical information to the clinic and back. On the one hand, the X-ray image is a kind of applied living anatomy, anatomia in vivo, a specific type of special dissection of a living person. For a number of organs with motor functions, such as the diaphragm, joints, heart and large vessels, gastrointestinal tract, etc., the X-ray method of examination is not only static, morphological, 'dead,' but also a dynamic, physiological, 'living' method. On the other hand, radiodiagnosis, like any other diagnostic discipline, has its own purely practical objective, an inseparable connection with the clinic, with a concrete person in all his rich biosocial diversity. This determines the place of the radiologist among representatives of other medical disciplines: the radiodiagnostician is a consultant, independent and autonomous, who knows not only his own specialty but is also necessarily fully knowledgeable in the anatomy and clinic of the particular discipline he serves. Of course, the practical goal of X-ray examination is the detailed diagnosis. In order to establish this diagnosis of a disease on the basis of X-ray examination data, it is necessary to methodically and sequentially pass through 5 stages. It is necessary a) to detect and take into account the so-called X-ray symptoms, b) to give a patho-anatomical interpretation of these X-ray signs, c) to become fully acquainted with all clinical data, d) to conduct a general differential diagnosis based on X-ray and clinical data, and e) to formulate conclusions orally or in writing, i.e., to make a conclusion. A. To detect and take into account X-ray symptoms means to understand the shadow X-ray picture, to compare the X-ray image in this case with a known normal picture, to draw a line between normal and pathological conditions, and to select those shadow signs on the film or screen that are not observed under normal conditions. It goes without saying that the basic requirement, mandatory for everyone who takes responsibility for reading an X-ray, is full familiarity with the specific features of X-ray normality. For example, it is not enough to know osteology or splanchology; one must know specifically X-ray osteology, the specific features of X-ray splanchology in all their infinite age, sex, constitutional, socio-professional, etc., diversity. Each shadow must receive an exhaustive optical-geometric and physical characterization. The analysis of the shadow image reduces to determining its basic properties. A shadow has: 1) number (single, solitary shadow, multiple shadows), 2) position (in the topographical-anatomical, spatial sense), 3) form (usually compared with geometric bodies), 4) size (in centimeters and millimeters), 5) intensity (depth), measured by contrast with the depth of normal structures, 6) pattern (e.g., uniform, homogeneous structureless shadow, mottled, reticular, honeycombed, etc., pattern), 7) contours, i.e., the boundaries between shadows of different intensity, denoted by terms such as 'even,' 'uneven,' 'smooth,' 'eaten away,' 'sharply defined,' 'blurred,' 'faded,' etc., and 8) mobility, resp. immobility. This shadow (skyalogical) analysis must be performed in simple expressions understandable to a physician without special training.

B. Pathoanatomical interpretation of X-ray symptoms is the translation of the X-ray language into the language of pathoanatomy, it is the clarification of the question of what pathoanatomical and, if possible, pathohistological changes underlie the X-ray symptoms, what is the anatomical substrate of the changes found on the film or screen. The more extensive a radiologist's knowledge of pathology and anatomy, the more the X-ray photograph tells him. The modern radiologist above all needs anatomical apperception. In this connection, it is necessary to know what deviations from the norm are generally found in X-ray representation and in exactly what form. It must be remembered that some very significant pathological changes are compatible with a completely normal X-ray picture; for example, acute osteomyelitis in its initial development is not yet accompanied by any X-ray deviations from the norm. Furthermore, a number of pathological processes, completely different in nature, can give the same X-ray symptoms, and conversely, the same pathological changes can manifest themselves in very different shadow combinations, in other words, certain anatomical pictures do not always correspond to the same specific X-ray shadow symptom complexes. Finally, for a number of X-ray signs, the anatomical substrate has not yet been established with sufficient completeness. This mainly concerns those benign or rare diseases or the very earliest stages of processes that exclude the possibility of operative or sectional control or experimental reproduction. Despite these difficulties, we are still, guided by X-ray signs, at present in most cases able to decipher the main anatomical changes in the organs being examined. B. Familiarization with the clinical picture in its entirety is necessary because X-ray examination is only part of the general examination of the patient, the X-ray method is only one of the many methods of general clinical examination. Radiography, of course, is not self-sufficient, it does not compete with other methods, but complements them, it is not intended to replace or devalue other research methods. After all, what is ultimately important is that in each individual case the correct diagnosis of the disease is made in general, and not specifically the 'radiological diagnosis'. The diagnosis is made on the basis of a synthesis of pathoanatomical, radiological, and clinical data. The X-ray photograph by itself, regardless of the patient from whom it was taken, has only very limited value. Comprehensive use of radiological data is possible only in the light of clinical medicine. Consequently, a complete accounting of all data from the anamnesis, the course of the process, especially the factor of duration, the methods of treatment used in the past, detailed examination by means of the usual 'old' clinical methods, familiarity with hematological, serological, etc. data are absolutely necessary for the radiologist. G. General differential diagnosis is based on a comparative clinical-radiological comparison of the symptoms of the disease. Clinical data alone are obviously insufficient for making a diagnosis; if they were sufficient to determine and study the disease, there would be no point in referring the patient to a radiologist. On the other hand, as we have seen, radiological data alone in a number of cases cannot ensure recognition. Only comparatively rarely is the X-ray photograph by itself sufficient for error-free recognition, i.e., it has pathognomonic diagnostic value and gives the radiologist the right to make a diagnosis not only independently of the clinical picture but even contrary to the data of clinical research. D. The formulation of the conclusion is still done very differently at present. Representatives of the old school of radiologists believe that the only objective thing that the X-ray photograph provides is the X-ray symptoms. The conclusion should contain only what is found when examining the films, completely independently of the data of clinical research, knowledge of which is desirable for the radiologist but not necessary. The evaluation of X-ray signs should be done by the physician-clinician, the attending physician, and he, not the radiologist, makes the final diagnosis of the disease. The vast majority of modern radiologists belong to the progressive school, which to a certain extent shares the opposite point of view. The radiologist is a consulting physician, a clinician in the area where he undertakes the examination of the patient, and not a narrow technician. It is clear that the most competent interpretation of the X-ray shadow image will be given by the radiologist himself, just as the most complete interpretation of the objective picture of skin changes will be given by the dermatologist, the evaluation of neurological symptoms by the neurologist, etc. The conclusion should contain a diagnosis or, if this is not possible, it should bring the attending physician as close as possible to this diagnosis. Thus, in addition to the desirable description of the pathological shadow picture in skiagraphic terms, the conclusion must necessarily contain a pathoanatomical decoding of the shadow symptoms, a comparative evaluation of the X-ray signs from the clinical point of view, and a brief conclusion about the nature of the disease. It goes without saying that such a conclusion increases the role and responsibility of the radiologist, and for the attending physician it is important not only what is found during the radiological examination, but also who performed this examination.-(For details, see separate organs.)