Relationship of computerized axial tomography in the diagnosis and staging of bladder tumors

The authors report four observations of actinomycotic brain abcess. One patient with multiple hemispheric abcesses and with stomatologic and pulmonary lesions, one with seemingly primary cerebellar abcess, one with associated hemispheric abcess associated with pneumopathy. About these four cases, they discuss the role of actinomycosis in infectious diseases of the central nervous system, and the elements necessary for the diagnosis. The neurological syndrom is not specific, but the discovery of visceral lesions is an excellent argument. From the histological point of view, the discovery of "granules" containing the bacteria conforms the diagnosis by special colorations. From the bacteriological point of view, the isolation of the germ is easy but its specific identification necessitates special techniques. The diagnosis of actinomycosis is indispensible to begin a correct treatment. For the authors, this treatment must associate surgical excision of the most extensive lesions and adapted antibiotherapy for more than four months.     

Cranial axial computerized tomography in children (author's transl)

This report on computerized tomography in 400 children confirms the high diagnostic value of the new method in neuropediatrics. 31 brain tumours were diagnosed in children. Tumors present themselves as lesions of latered density compared to that of brain matter. Intravenous injection of contrast media increases the density of various lesions as tumors, angiomas, acute infarctions and abscess. Infarctions are low density lesions whereas hemorrhage is a high density lesion and both are thus safely differentiated. Edema may be visualized in the vicinity of tumours in brain injuries and in encephalitis. The normal ventricular system, hydrocephalus, cerebral malformations and subdural hygroma are easily demonstrated. Diseases of the orbits may also be detected.     

Implementation and evaluation of patient-specific three-dimensional internal dosimetry

Current methods for calculating the absorbed dose in a target region from a source region rely on a standard "reference man" geometry and assume an uniform distribution of radiolabel. While this approach is acceptable at the low levels of radioisotope administered for most diagnostic purposes, the generality of the calculations is not adequate for doses at the higher levels required for therapy and is not easily extendible to tumor dosimetry. METHODS: We have developed an integrated system which utilizes patient anatomy and radionuclide distribution in the calculation of absorbed dose rate or total dose to any user-defined target region. Images of radionuclide distribution (PET/SPECT) are registered to anatomic images (CT/ MRI) and then entered into a three-dimensional internal dosimetry software system (3D-ID) where regions of interest are defined. Dose calculations are performed by the mathematical convolution between a user-specified, dose-point kernel with the activity in the source volume over the target volume. The resulting dose rate distribution may be scaled by cumulated activity to yield absorbed dose. In addition to calculating the mean dose, dose-volume histograms may be generated which plot absorbed dose with respect to percent of volume. The method was evaluated using selected standard man phantom organs. RESULTS: Dose estimates for two patient studies are included to illustrate differences between patient-specific and MIRD-based calculations. The package provides an alternative approach to image display and three-dimensional internal dose calculations. CONCLUSION: The dose-volume histogram representation of absorbed dose to a target volume provides valuable information in assessing tumor control probability and normal tissue toxicity.     

Long-term assessment of early alveolar bone grafts using three-dimensional computer-assisted tomography: a pilot study

Fifteen patients with complete unilateral cleft lip and palate who had primary alveolar bone grafting were studied with computer-assisted tomography at a mean age of 12 years. Keeping the maxillary alveolar crest parallel to the plane of the scan, 1.5-mm cuts of the maxilla were made from the infraorbital rim to the gingival third of the crowns of the teeth. A single operator reformatted the data into three-dimensional images using the Maxiview 3200 computer workstation. This allowed examination of the position, size, and spatial relationship of the grafted area and quantification of the amount of bone coverage of root surface and bone height of the alveolus in or adjacent to the graft site. Ten patients showed a lateral incisor in the line of the cleft. The average bony coverage of these tooth roots was 76.5 percent. In the five patients in whom there was lateral incisor agenesis, the canine root had average bony coverage of 82.6 percent. The average height of bone at the lateral incisor was 8.7 mm; at the canine, 14.1 mm. In two patients in whom there was only 42 percent tooth root coverage, the teeth were still viable, stable, and without mobility. Computed tomographic (CT) scans of the 15 patients demonstrated good graft survival with adequate volume. The functional and aesthetic status of the dentition in the area of the cleft also was demonstrated.     

Computerized axial tomography: estimation of spatial and density resolution capability

The spatial and density resolution capability of the EMI-Scanner device for computerized axial tomography has been determined in vitro. For density differences greater than +/-1 per cent the spatial resolution is 6 X 6 mm. For density differences of 3 per cent and greater the resolution is 3 X 3 mm. Density resolution is at least +/-1 per cent for objects greater than 1 cm. Preliminary data on in vitro measurement of X-ray linear attenuation coefficients in tissue biopsies and standard solutions are given, together with the early results of enhancement of tissue density differences in vivo. Implications of this new technique for an in vivo neuropathology are suggested.     

The lesions of the pterygopalatine and infratemporal spaces: Computed tomography evaluation

OBJECTIVE: The purpose of this study was to categorize the computed tomography features of lesions affecting the pterygopalatine fossa and infratemporal fossa and thus aid in the diagnosis of these lesions. DESIGN: Eighty-six patients with lesions of the pterygopalatine fossa and infratemporal fossa were examined with computed tomography; the lesions were confirmed by both surgery and biopsy. The patients were divided into three groups: group I consisted of patients in whom the lesions had originated in one or both fossae; group II, of patients in whom the lesions originated in other oral and maxillofacial regions but showed extension into the pterygopalatine and infratemporal fossae; and group III, of patients in whom the lesions had multicentric origins. RESULTS: Of the 11 cases in group I, demarcation was confined to both fossae in 4 patients, and involvement of the adjacent structures was shown on computed tomography images in 7 patients. Involved structures included the maxillary sinus (4 sides), nasal cavity (3 sides), mandibular ramus (6 sides), buccal space (2 sides), base of the skull (5 sides), palate (3 sides), and parapharyngeal space (5 sides). In the 70 cases in group II, computed tomography images showed that lesions had invaded both fossae via following routes: (1) 40 lesions in the maxillary sinus had infiltrated posterolaterally into 26 pterygopalatine and 39 infratemporal fossae; (2) two nasal cavity and three nasopharynx tumors had infiltrated laterally or lateroanteriorly into five pterygopalatine and one infratemporal fossae; (3) lesions originating in mandibular rami (9 lesions), buccal regions (4 lesions), parapharyngeal spaces (1 lesion) and parotid glands (1 lesion) had intruded medially into 15 infratemporal fossae; (4) two temporal bone tumors had encroached inferiorly on two infratemporal fossae; (5) four palate tumors had led to involvement of three pterygopalatine and four infratemporal fossae; and (6) four inflammatory diseases of the facial spaces involved two pterygopalatine and four infratemporal fossae. Group III lesions (5 cases) affecting one pterygopalatine and five infratemporal fossae were hemangiomas; one was a malignant lymphoma. CONCLUSION: Group I lesions may involve the adjacent anatomic structures of both pterygopalatine and infratemporal fossae in every direction. Group II lesions that correspond to the various origins of the maxillofacial region have different pathways of infiltration into the pterygopalatine or infratemporal fossae. Computed tomography examination is very important in the evaluation of lesions involving the pterygopalatine and infratemporal fossae.     

How accurate is size measurement of pancreas cancer masses by computed axial tomography (CT) scanning?

With the advent of preoperative radiotherapy for pancreas cancers, their measurement by imaging is rendered more important, so that outcome data from various treatment programs may be compared. Two radiologists have examined tumor size measurements from 29 patients by CT scans obtained within a week of measurement in the Pathology Department after resection. The radiologists assessed these scans independently from one another and blinded from the pathologic measurement. The largest diameter of their readings was compared to the largest diameter of the tumor measured by the Pathology technician. The correlation between radiologists (P < 3 x 10(-8) was excellent. Correlation between the average of the two radiologic estimates of greatest tumor diameter and actual tissue measurement is excellent for tumors (n = 21) greater than 2 and less than 5 cm in diameter (P < 0.03), but of four specimens measured in the Pathology laboratory as less than 2 cm, all were measured by the radiologists as being at least 1.5 cm larger. Twenty of the 29 cancers (69%) were measured by two radiologists to be within 1 cm of the actual diameter. The nine specimens producing the greatest errors were two with diffuse mucinous tumors throughout the gland (radiologists undercalled by 2.5 cm), one 7 cm mass with a cystic center composed of necrotic cells (overcalled by 2.5 cm, perhaps because of deformity or release of fluid in Pathology), four small masses (1, 1.5, 1.5, and 1.5 cm in diameter), smaller than the normal diameter of the pancreas head, and two tumors with inexplicably inaccurate size estimates.(ABSTRACT TRUNCATED AT 250 WORDS)     

Computed tomography of the tongue and floor of the mouth

The anatomy of the tongue and floor of the mouth is readily discernible by computed tomography (CT) because of low-density fascial planes that outline the extrinsic musculature, lingual arteries, and hypoglossal nerves. Although the tongue is accessible to the examining finger, few patients can tolerate a detailed palpation. In planning for a partial glossectomy, CT scanning aids the surgeon who must be sure that the tumor is unilateral or that at least one lingual artery and one hypoglossal nerve can be preserved. The CT scans of 30 patients were reviewed for background anatomy. Pathologic changes are summarized for 16 extrinsic lesions and 11 intrinsic tumors. The status of the midline could be confirmed in 28 of the 30 patients. The fascial plane distortions by malignant intrinsic and extrinsic lesions are discussed.     

Computed tomography using algebraic reconstruction techniques (ARTs) with different projection access schemes: a comparison study under practical situations

In a previous report we presented a novel ART technique with the projections arranged and accessed in a multilevel scheme (MLS) for efficient algebraic image reconstruction, but whether the scheme is still superior in real situations where the data are noisy is unknown. In this paper, we make a detailed comparison between MLS and the other two conventional projection access orderings in ART: the random permutation scheme (RPS) and the sequential access scheme (SAS). By simulating reconstructions of a human head using different sizes of detector, taking different numbers of projections, each measurement under a different number of photons, a full mapping of the reconstruction accuracy measured by correlation coefficient for the three schemes has been made. Test results demonstrate that one-iteration MLS produces the best reconstruction in many situations. It outperforms one-iteration RPS when the noise level is low. SAS in many cases can never attain the image quality of one-iteration MLS, even with many more iterations. A convergence test using different initial guesses also demonstrates that MLS has less initial dependence. In the Fourier domain, it also represents an efficient and fast implementation of the Fourier slice theorem.     

Urologic applications of multiplanar and three-dimensional computed tomography

The introduction of helical computed tomography (CT) has resulted in improved quality of multiplanar reformations and three-dimensional reconstructions in the chest and abdomen and has made CT angiography a clinical reality. These imaging techniques are useful for evaluating the urinary tract, adding a new dimension to its display, resulting in improved diagnosis of renal and perirenal disease. This article reviews the indications and techniques utilized for multiplanar and three-dimensional CT for urology. The advantages and limitations are discussed, and normal and pathologic findings in the urinary tract illustrated.     

Computed tomography of the ethmoid labyrinth and adjacent structures]

Esthetic body contouring has become the most common esthetic surgical procedure since the advent of liposuction. The interest in this surgery led us to focus on the physiology of adipose tissue that behaves differently according to its localisation. Besides, a better knowledge of the anatomy of the subcutaneous tissue has helped us to treat the deep and superficial adipose deposits more effectively. Many technical refinements have been proposed in order to improve the results and decrease the risks. Local infiltration allows us to remove large amounts of fat with a minimal blood loss. Syringe aspiration is less traumatic and avoids the purchase of an expensive suction pump. However, although the technique of suction lipectomy looks simple, this procedure can induce important local complications (contour deformities, skin waves, ...) and general complications (pulmonary embolism, fat embolism, cardio-pulmonary decompensation). A rigorous technique, performed by a well trained surgeon in an adequate medical environment is essential to obtain the best results with suction lipectomy. In order to correct excesses of skin on the abdomen or the thighs after an important weight loss, skin excisions will be necessary. In there cases, the scars are often wide and sometimes difficult to hide.     

Computed tomography in schizophrenic patients. Results from 15 patients. Review of the literature (author's transl)

The authors analyzed the scans of 15 chronic schizophrenic patients, apparently deteriorated, all of whom were long standing in-patients. They found 11 pathological cases (6 cortical atrophies and ventricular enlargement, 3 ventricular enlargement, 1 cortical atrophy, 1 cerebellar atrophy). With one exception all these atrophies were slight. The authors findings are comparable with those already reported in other studies. The article also summarizes the results of earlier studies of schizophrenics, by pneumoencephalography which are similar. Although no firm conclusions can be drawn, for such a limited sample, in particular due to the lack of any visible correlation between the pictures obtained and clinical diagnosis or prognosis, the consistent appearance of tomographic anomalies justifies continued research on these lines.     

The application of non-annealing thermoluminescent dosimetry (TLD)

Conventional use of Thermoluminescence (TL) in radiation dosimetry is very time-consuming. It requires repeating the procedures of preheating and annealing. In an attempt to simplify these procedures, we conducted an experiment of non-annealing TL dosimetry. This article reports the experiment's results. We adopted Lithium Fluoride (LiF) chip (TLD-100) in polystyrene under the exposure of Co-60, and the result was taken by HAR-SHAW-4000 TL reading system. The TL response was analyzed, including linearity, reproducibility and fading test. Because non-annealing TL response was greatly influenced by residual electron, TLD calibration curves were separated into two parts: (1) high dose region (HDR, 50-1500 cGy); (2) low dose region (LDR, 0-50 cGy). When TL dosimeters were exposed to a single high does (about 500 cGy), the HDR could be reproduced within 3% and fit a good linearity. For LDR, we had to give up the tail of glow curve in the high temperature region. We could then get good linearity and reproducibility. Furthermore, fading of non-annealing was apparently larger than annealing. We could control the fading of non-annealing was apparently larger than annealing. We could control the fading influence within 1% by taking the TL reading one hour after exposure. On the other hand, a combination of photon and electron exposure was also performed by non-annealing TL dosimetry. The results were compatible with Co-60 exposure in the same system.     

Computed tomography of the normal feline nasal cavity and paranasal sinuses

We studied physical, cognitive, emotional and quality-of-life changes noted by relatives in a sample of 65 severely traumatic brain injured (TBI) patients several years after injury. The purpose of the present study was to evaluate the families perception of these changes and their need for information concerning the consequences of TBI. Our results indicated that the perceived changes in behavioural and affective symptoms and in the patient's quality of life were most closely associated with the need expressed by family members for information concerning, TBI. We also found that family relationships were especially affected by problems in the behavioral and affective domain, and the decrease in patient quality of life, as reported by relatives. These findings underline the importance of providing the relatives of TBI patients with information about the consequences of the injury with particular emphasis on behavioural and emotional disturbances, in order that they might cope better with these problems.