Film Subtraction Research Articles

Pitfalls in the diagnosis of extraadrenal pheochromocytoma.

Precise localization of pheochromocytomas is an essential part of their preoperative management. As a significant number of these tumors may be extraadrenal multiple, or hypovascular, they may not be detected by computerized body tomography (CBT) or arteriography without film subtraction. In seven patients with extraadrenal pheochromocytomas, all tumors were demonstrated by arteriography. In two cases, subtraction films revealed tumors that had not been visualized on the non-subtraction films. CBT, performed in four patients, demonstrated a mass in two but failed to visualized tumors in the other two.

Intravenous Angiography Using Scanned Projection Radiography: Preliminary Investigation of a New Method

The use of digital subtraction techniques combined with fluoroscopy has rekindled interest in arteriography using intranvenous injections of contrast media. A new method is proposed for intravenous angiography in which an x-ray source and xenon detector array from a computed tomographic (CT) scanner are used to scan a region of interest to produce projection image. In order to provide adequate visualization of small concentrations of iodine in blood vessels, a subtraction scheme is used to remove the contribution from overlapping soft tissue and bone. Initial experiments with a temporal subtraction algorithm on phantoms have demonstrated the ability to image simulated blood vessels of 1.7-mm diameter containing dilute diatrizoate with an iodine concentration of 3.7 mg/cc, at an exposure of less than 100 mR. Vascular structures 5-8 mm in diameter have been imaged in dogs with iodine concentrations of less than 37 mg/cc using temporal subtraction. Principal advantages of the method over other film or fluoroscopic subtraction techniques are: 1) wide dynamic range an low noise of the (CT) detectors, providing excellent iodine sensitivity; 2) high scatter rejection; and 3) efficient utilization of x-ray dose.

A modified blurred undersubtraction method (BUS) and its applications.

A modification of a previously described method of enhancing radiographs for photography is presented. The mask to be used during photography is produced by exposing a subtraction film with the radiograph and two layers of diffusing glass in between it and the x-ray copier. Various applications for producing other types of masks are also discussed.

Hemiplegia as a Complication of Therapeutic Embolisation of the Internal Maxillary Artery

SUMMARYA hemiplegia complicating a successfully treated angioma arising from the internal maxillary artery is described. The probable pathogenesis of the complication is discussed.A right common carotid arteriogram and a selective right external carotid arteriogram were carried out.The common carotid arteriogram showed that the intra‐cerebral arteries were normal. The external carotid arteriogram showed an enlarged main stem and a greatly enlarged internal maxillary artery (Figure 1). A rapid series of films in the antero‐posterior and lateral projections were taken and subtraction films prepared, to identify the feeding vessels to the arterio‐venous malformation and to exclude any connections between the external and internal carotid arterial systems.The internal maxillary artery and its branches were the only feeding vessels demonstrated as supplying a large arterio‐venous malformation situated in the pterygo‐palatine fossa (Figure 2).Because of the anatomical site of the angioma and its wide ramification, it was decided that the most suitable method of treatment would be embolisation of the main feeding arteries rather than an attempt at surgical removal.Following embolisation the patient developed a hemiplegia. A C.T. Scan confirmed the presence of an area of infarction in the right hemisphere of the brain. The hemiplegia slowly improved over a period of four months but left a residual partial paralysis of the left arm.The embolisation therapy was successful in abolishing the bruit and the vascular hum complained of by the patient.

Epigastric Pain With Falling Hematocrit

History A 56-year-old woman was admitted with severe epigastric pain after having eaten a large meal. The patient was diaphoretic and had tachycardia. The pain radiated across the abdomen and was suggestive of biliary colic. The blood pressure was 110/70 mm Hg, with a regular pulse rate of 144 beats per minute. The hematocrit value was 34.3%, and the hemoglobin concentration was 12 g/dL. The initial diagnosis was cholecystitis, cholelithiasis, and gallbladder colic. An intravenous cholangiogram was normal. The hematocrit value fell to 25.7%, and the hemoglobin concentration fell to 8.8 g/dL in 24 hours, with a blood pressure of 70/40 mm Hg. There was no evidence of bleeding from the gastrointestinal tract. An emergency angiogram was performed (Fig 1 and 2). Diagnosis Aneurysm of the inferior pancreaticoduodenal artery with retroperitoneal bleeding. Subtraction film of the early arterial phase of the superior mesenteric angiogram (Fig 1) shows a 2-cm aneurysm

A simple method for reproducing Polaroid images as transparencies.

A method to produce transparencies on radiographic subtraction film from Polaroid images using equipment available in most radiology departments is presented.

A technique to improve visual perception characteristics of subtracted roentgenograms.

A method of X-ray subtraction, which utilizes a translucent graphic arts film (DuPont Cronapaque) for the final image, is presented. This print may be viewed by either transmitted or reflected light. The results appear to be superior to conventional transparency subtraction film.

A Simple Technique for Photographic Image Enhancement of Subtraction Films

The authors describe a simple technique for improving the contrast of subtraction films of uneven density by collimating the light source with aluminum cylinders, thus enhancing the area of principal interest while preserving the information on the remainder of the film. This “focused” beam increases the relative amount of light reaching the darkest area of the film, producing a final product of more uniform overall density.

An apparatus for rapid copying and subtraction of radiographs.

The purpose of this communication is to describe an apparatus for rapid copying and subtraction of radiographs utilizing Kodak RP/D X-Omat Radiograph Duplicating Film and Kodak RP/SU Subtraction Film. Both techniques have been standardized so that they can be carried out by the dark room staff. Radiographs can be copied with the minimum of handling and without interruption of a busy dark room routine. Subtraction can be carried out by the dark room staff so that the additional radiographs are available when the special investigation is being reported.

Angiographic demonstration of brain injury without significant mass lesion

Evidence of brain damage was demonstrated in two patients without significant mass lesions by the presence of early venous filling and abnormal contrast staining. The vascular changes were most prominent on subtraction films. It is likely that these angiograms demonstrated the "luxury perfusion" phenomenon described previously in areas of damaged brain.

Angiography in angiomas of the face.

ANGIOGRAPHY IN ANGIOMAS OF THE FACEM. LEA THOMAS and M. R. ANDRESSAudio Available | Share

Light intensity variation. A novel approach to subtraction technique.

The authors describe a simple method of subtraction which involves varying the light intensity in printing the diapositive and final subtraction. Once standardized, subtraction can be performed routinely. This technique eliminates the necessity for second-order subtraction and simplifies the procedure by using conventional x-ray film for the final subtraction film.

Subtraction Films in Angiography

Subtraction Films in Angiography

Color-additive subtraction.

Conventional radiographs remain the most valuable method of recording the x-ray image. Black-and-white subtraction has greatly enhanced the quality of arteriographic studies. Color-additive subtraction is an embellishment of the standard radiographic subtraction. It is a display method of particular value for medical illustrative material and medical teaching. The method outlined below represents a new simplified technic of producing color-additive radiographs. The procedure is significant in that it is simple and relatively inexpensive. The quality of color presentation is excellent. The method is significantly different from the previously described technics (1, 4-6) in that it is a contact process and is capable of producing superior radiographic detail. Method The technic used for producing color-additive subtraction films is summarized in point form as follows: I. Initial Black-and-White Subtraction A. Mask Production 1. Place a sheet of Kodak commercial film (Estar thick base), emulsion side up, directly below a light source. 2. Place the preliminary film (no contrast material) over the commercial Estar film. 3. Place a sheet of clear glass over the two sheets of film to ensure proper film contact. 4. Expose the films to a 15-watt light source for three seconds at a distance of 6 feet. 5. The exposed Kodak commercial film (Estar thick base) is then processed through the R.P. X-Omat processor. B. Superimposition of Mask and Contrast-Filled Film 1. Select a contrast-filled film to be subtracted, and place it on a view box in the normal viewing position. 2. Align the mask and the contrast-filled film so that they are perfectly superimposed. 3. When the alignment is correct, secure the films together with tape. C. Production of the Subtracted Film 1. Place a sheet of Kodak commercial film (Estar thick base) with the emulsion side up directly below a light source. 2. Place the aligned pair of films over the commercial Estar film. 3. Place a sheet of clear glass over the three films to ensure good film contact. 4. Expose films to a 15-watt light source for eight seconds at a distance of 6 feet. 5. The exposed Kodak commercial film (Estar thick base) is then processed through the R.P. X-Omat processor. II. Color-Additive Process A. Background Blue Copy 1. Use the same contrast-filled film as is employed in obtaining the black-and-white subtraction. Place over this film a sheet of blue ultra-high-speed Diazo film.2 The two sheets are then fed into a Blu-Ray white printer, exposing the color foil to ultraviolet light. 2. The exposed sheet of color foil is now fed into a Blu-Ray developer which dry-develops the foil by use of ammonium fumes. 3. The background film shows the general anatomy in light blue with the contrast-filled vessels appearing white.

Congenital Anomalies of the Carotid Arteries, Including the Carotid-Basilar and Carotid-Vertebral Anastomoses: An Angiographic Study and a Review of the Literature

Anyone interested in cerebral and cervical arteriography would benefit from reading and studying this book. In addition to presenting common and uncommon anomalies of the carotid and vertebral arteries, the author has used embryology extensively to explain and understand how these interesting variations come about. The three primitive anastomoses (trigeminal, otic, and hypoglossal) between carotid and basilar arteries are described, but, in addition, the less-well-known suboccipital (proatlantal) and cervical intersegmental anastomoses are illustrated. The numerous connections between internal and external carotid arteries made prominent after occlusive disease of the internal carotid are well described and their relationship to embryological structures pointed out. They are illustrated by ordinary angiograms, subtraction films, stereoscopic films, and diagrams. The references (up to April 1967) are well chosen. The description of the wonderful net of arteries which connect internal and external carotid arteries in animals lays the groundwork for understanding the rare human cases included

An exercise in radiologic-pathologic correlation.

There are only a few localized pulmonary abnormalities which by their radiographic appearance and location suggest specific pathologic entities. More often the radiologist is faced with a complex of puzzling chest densities, a nonspecific clinical picture, and confusing laboratory data which make a diagnosis of the pathologic problem almost impossible except by thoracotomy and tissue analysis. The case presented this month, however, does not fit this pattern but affords the radiologist the rare opportunity to render a precise and practically histologic diagnosis. Radiology The initial radiographs of the chest (Fig. 1) show a well defined parenchymal abnormality involving the left lower lobe. The density is relatively homogeneous, and there is no evidence of pleural fluid or associated adenopathy. The x-ray appearance is thus consistent with pneumonia. Follow-up chest examination one week later demonstrated partial resolution. Approximately six months later, a repeat chest examination (Fig. 2), performed because of anterior chest pain and cough, demonstrated cystic changes in the same location. No fluid levels are noted, however, and again there is no evidence of pleural effusion, adenopathy, additional pulmonary lesions, or contiguous vertebral abnormality. The persistence of the findings associated with recurrent symptoms and cystic changes suggests a more chronic pulmonary process such as bronchiectasis. Selective bronchography reveals nonfilling of the terminal portions of the major bronchi to the abnormal area (Fig. 3) as well as slight lateral displacement of the adjacent normal bronchial segments. The lack of filling in the cystic areas suggests the probability of an abnormal pulmonary segment, specifically an intralobar bronchopulmonary sequestration which must have had a small communication with the bronchial tree (to account for air-filled cysts) after breakdown secondary to infection. Since these embryologic defects are usually supplied by one or more aberrant arteries, percutaneous transfemoral thoracic aortography was performed as the next diagnostic procedure. It discloses a single aberrant vessel arising between the intercostal arteries at T-9 and T-10 on the left (Fig. 4). Selective catheterization shows the vessel to be of larger caliber than the intercostal arteries. Its course is dorsolateral with mild stretching and arborization around the periphery of the cysts (Fig. 5). Despite adequate arterial filling, venous drainage is not demonstrated satisfactorily. Subtraction films suggested venous drain age to the left atrium through pulmonary veins, which is the usual route in intralobar pulmonary sequestration. Clinical Findings and Analysis The patient is a 19-year-old Negro female who had no pulmonary complaints until the age of eighteen when she experienced an episode of fever, chills, and cough. A chest radiograph at this time showed consolidation of the left lower lobe and she was treated with tetracycline.

Nasopharyngography: its technic and uses.

Nasopharyngography has been performed int ermittently for many years. Most of the reports concerning contrast studies of the nasopharynx have been in the foreign literature (1–3, 5). In the United States, nasopharyngography is performed in various centers, but it has not gained widespread acceptance. With advances in head and neck surgery and the radiothe rapy of nasopharyngeal cancers, however, additional methods of diagnosis are needed. In our prac t ice, contrast-medium nasopharyngography has been of considerable aid in the diagnosis of benign lesions, as well as in localizati on of the malignant, and supp lements the present methods of clinical examination. The nonradiographic technics available for nasopharyngeal examination include indirect visualization with mirrors, palpation, rhinoscopy, and nasopharyn goscopy (3). Attempts at radiographic methods of examination of the nasopharynx have been several. Lateral roentgenograms with soft-tissue technics have been useful , but not the frontal views with soft-tissue technics, as here the bony st ructures of the skull are superimposed and obscure the air-tissue contrast. Laminagrap hy has been tried, but with visualization which has often left something to be desired. Roentgenographic methods of visualization are not designed to replace direct methods. Rather, they are to supplement them as a barium swallow evalu ation of the esophagus supplements direct esophagoscopy. Both give information, but findings of one method supplement and confirm those of the other. The area is first filled with contrast material, then emptied. The air-contrast studies with the mucosa coated with medium have overcome the major problems in roentgenographic visualization. We feel these air-contrast films are the real addition to nasopharyngography and the anatomic evaluation of the nasopharynx. Various contrast materials have been employed for nasopharyngograms. Lipiodol was one of the first (2, 3), but it proved too dense for optimal ante roposterior visualization and did not coat the mucous membranes for good air-contrast studies. Oily Dionosil has proved satisfactory. A water-soluble, moderately viscous medium would be ideal, but none is available. We have had good results with a 1.25–1.5 per cent solution of car boxymethylcellulose and Micropaque (6, 7). This mixture fills the nasopharynx slowly but coats well for air-contrast visualizati on. Our technic for nasopharyngography is shown in Figure 1. Preliminary films are obta ined in the anteroposterior vertical and cross-table lateral positions with a 40-in target-film distance. This insures both adequate penetration and also films for comparison with th e contrast studies. Too, if needed, subt raction films may be obtained at a later time for bett er visualization. The equipment is simple. No anesthesia is necessary. If the patient has a raw or irritated nasal mucosa, th en spraying a topical anesth etic before instillation of medium could be useful, but in general it is not necessary.

A Simplified Method of Subtraction and its Application to Renal Arteriography

A simplified method of obtaining subtraction films is described, using cassettes, films, and darkroom solutions normally available in the X-ray department. Three cases are described, which illustrate the value of subtraction in renal arteriography.