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PubMed1990

[Finite element analysis on physiological mobility of individual teeth].

The initial movement of the tooth was investigated by the finite element method. The mechanical properties of the periodontal membrane were estimated from the results of the simulation. The analysis was made by using an 8 point isoparametric finite element method. The upper central incisor with an axial directional load was simulated. The concept of the apparent elastic modulus was introduced to the stress-strain relation of the soft tissue, that is, soft tissue such as the periodontal membrane and the gingiva was considered to have stress dependent elastic moduli. At the first stage of the simulation, the stress and strain distributions in the paradentium were calculated by the conventional method. From the next stage, the apparent elastic moduli for the soft tissue were introduced to the calculation, that is, the elastic moduli for the soft tissue were computed from the calculated equivalent stresses of the previous stage. The calculations were repeated until the displacement values converged. The initial displacement of the tooth was not proportional to the applied load but showed a non-linear relationship. The relationship between load and displacement was approxiated by the n-th power equation. These results were in agreement with the clinical experimental results. The periodontal membrane is built up of different elastic moduli. The elastic moduli were low at the alveolar edge and the root apex. The equivalent stresses of the periodontal membrane were marked low in the alveolar edge and the root apex. In conclusion, the concept of the apparent elastic modulus is useful to investigate the initial movement of the tooth and estimate the mechanical properties of the periodontal membrane.

Computer Simulation↗
PubMed1981

Intensified tomography: enhancement of soft-tissue discrimination in conventional tomography of the brain. A comparison with computed tomography.

A new technique to enhance the conventional tomographic images of soft tissues such as the brain is described. The method, called intensified tomography, optimizes the information available from conventional tomography through the use of three modifications: a specially designed filter to attenuate selectively the x-ray beam at the source to compensate for the variable shape of the skull, an improved blurring movement to reduce system artifacts, and enhanced image contrast by the superimposition of several identical images on the same film or television screen. Intensified tomography was performed in 200 patients. Ten of these tomographic images later were compared with computed tomographic (CT) scans to confirm that the ventricles could be imaged with intensified tomography. An unexpected case of lenticulocapsular calcification was also demonstrated by intensified tomography and confirmed by CT. It is proposed that intensified tomography be developed as a preliminary screening technique to be used in places where CT is not readily available.

Brain↗
PubMed1978

Computed tomography of the orbit with special emphasis on coronal sections: Part II. Pathological anatomy.

Visualization of orbital soft tissue structures by computed tomography in direct coronal and axial studies is extremely useful in diagnosis. Direct enlargement viewing of scans has disclosed minute anatomical details. This study reviews some of our experiences in the investigation of a variety of lesions within the orbit and attempts, in particular, to illustrate the value of direct coronal studies.

Adult↗
PubMed2003

Subcutaneous undifferentiated sarcoma induced by N'-ethyl-N'-nitrosourea in rat: radiology, histopathology and mutagenesis.

The aim of the present study was to investigate high dose and long-term effects of a common industrial agent, N'-ethyl-N'-nitrosourea (ENU), on soft tissues in a rat model. ENU, which was dissolved in polyethyleneglycol (PEG) was injected intra-peritoneally once a week (300 mg/kg) in the first experimental group. The second group received only PEG. The control group was free of any agent administration. Only rats treated with ENU for a period of 45 weeks developed large subcutaneous tumours (approximately 5-9 cm in size). Tumoral tissues were examined radiologically, histopathologically and immunohistochemically. There was no bone destruction beneath the soft tumoral tissues in direct X radiograms. Computed tomographic (CT) images showed heterogeneous soft tissue masses with a density ranging from 50 to 65 HU. Macroscopically, all tumors were circumscribed with a gray-white surface in the cross-sections. The histopathological and immunohistochemical examination of the subcutaneous tumoral tissues showed a spindle cell type of sarcoma. Lymphatic and skeletal muscle invasion, atypical mitoses and necroses were determined in all tumoral tissues in the experimental group. A somatic point mutation was detected in exon 2 of KRAS oncogene in sarcoma tissues using the single strand conformational polymorphism (SSCP) analysis. In conclusion, the activated KRAS oncogene might contribute to the progression of subcutaneous sarcoma in experimentally ENU induced rats due to point mutation.

Animals↗
PubMed1984

Soft-tissue CT changes in pelvic venous thrombosis.

The computed tomographic (CT) changes in the soft tissues of the pelvis are presented in three patients with pelvic venous thrombosis. Pelvic venous thrombosis may lead to swelling of surrounding muscles and may present as a pelvic mass. This mass can simulate a tumor clinically, radiographically, and sonographically, but its origin and cause can be demonstrated by CT. Proper understanding of such changes may prevent an erroneous diagnosis of enlarged pelvic lymph nodes or an inflammatory or neoplastic mass.

Adult↗
PubMed2003

Computed tomography-guided core needle biopsy for bone and soft tissue tumors.

BACKGROUND: Imaging-guided core needle biopsy is a well-established technique for the diagnosis of bone and soft tissue tumors and tumor-like lesions in specialized orthopedic oncology centers. OBJECTIVE: To present our results of computed tomography-guided core needle biopsy with assessment of the accuracy of the technique. METHODS: Between July 1998 and October 2000, 215 CT-guided core needle biopsies were performed and histologically examined in the Unit of Bone and Soft Tissue Pathology, Tel Aviv Sourasky Medical Center. There were 80 soft tissue and 135 bony lesions. All biopsies were performed by the same radiologist and the histologic examination by the same pathologist. To assess the accuracy of the procedure, we compared the diagnosis at biopsy with the diagnosis after definitive surgery (when available). RESULTS: Bone core needle biopsy (n = 135) showed malignancy in 89 cases (primary or recurrent bone sarcoma, lymphoma, myeloma, metastatic carcinoma or melanoma). There were 29 benign lesions. In 17 cases the result was inconclusive and an open incisional biopsy was performed. Of the 80 soft tissue biopsies, 35 were malignant (25 soft tissue sarcomas, 6 lymphomas, 4 metastatic carcinomas); 40 were benign (myositis ossificans, neurofibroma, desmoid tumor, schwannoma, hematoma and others), and 5 were inconclusive and followed by an open incisional biopsy. The core needle biopsy histologic diagnosis was compared with that of the definitive surgery and the diagnostic accuracy was 90%. Only three samples initially diagnosed as benign turned out to be malignant. No significant complications occurred during the procedures. CONCLUSIONS: CT-guided CNB of musculoskeletal lesions is a safe and effective procedure that assures sufficient and proper material for histologic examination. The accuracy of this method in our center was 90%. Tumor sampling is extremely important, especially in soft tissue sarcomas, and cores should be taken in different directions, including areas of necrosis. The processing is quick, especially for bone CNB, and diagnosis can be achieved within 24 hours. The material undergoes excellent fixation and the immunostains are reliable.

Biopsy, Needle↗
PubMed1996

Three-dimensional facial morphometry and conventional cephalometrics: a correlation study.

The purpose of this study was to compare the correlation between three-dimensional soft tissue measurements obtained with three-dimensional digital infrared photogrammetry and two-dimensional data obtained with conventional cephalometry. Facial morphometry was investigated in a group of 20 healthy young men using both systems on each subject. From the lateral radiographs, conventional two-dimensional cephalometric hard and soft tissue data were calculated, while three-dimensional linear and angular soft tissue measurements were computed from the infrared photogrammetry. The correlations between the two sets of measurements were calculated. Three-dimensional soft tissue measurements correlated to cephalometric data primarily contained information useful for esthetic analysis. The soft tissue infrared measurements also allowed evaluation of the general hard tissue situation. Since the soft tissue measurements are calculated with a noninvasive system, they could be computed more frequently during treatment and be used to supplement pretreatment and posttreatment radiographs.

Adult↗
PubMed1994

The validity of the prediction of Soft Tissue profile changes after LeFort I osteotomy using the dentofacial planner (computer software).

The purpose of this study was to examine the validity of the prediction of soft tissue changes after LeFort I osteotomy with the DentoFacial Planner (DFP) (computer software). The preoperative and postoperative lateral cephalograms of 21 white adult orthodontic patients (10 males and 11 females) who underwent only LeFort I osteotomy as part of their overall treatment were digitized. A coordinate system of X and Y axes were used to assess the amount and direction of movement of the maxilla. The SN + 7 degrees was the X axis, and a perpendicular to this plane from nasion was the Y axis. The sample was divided into two groups depending on the amount of forward movement of the maxilla. More than 2 mm of anterior placement of the maxilla comprised the advancement group (13 patients) and less than 2 mm comprised the impaction group (8 patients). The selection criteria for the sample were (1) before and after cephalograms taken with lips in repose and in centric occlusion; (2) all preoperative records taken almost immediately before surgery; (3) postoperative records taken at least 6 months after surgery and checked by regional superimposition of the preoperative and postoperative lateral cephalograms onto the maxilla and the mandible. No tooth movement occurred between the time the records were taken. The following soft tissue landmarks were examined: pronasale, subnasale, stomion superior, middle upper lip, stomion inferior, middle lower lip, labrale inferior, labiomental fold, and pogonion. The results indicate that for some of these landmarks the amount and direction of soft tissue changes differed between the DFP prediction and the actual surgical changes by LeFort I osteotomy.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed2002

Computer-controlled motorized endoscopic grasper for in vivo measurement of soft tissue biomechanical characteristics.

Accurate biomechanical characteristics of tissues are essential for developing realistic virtual reality surgical simulators utilizing haptic devices. Surgical simulation technology has progressed rapidly but without a large database of soft tissue mechanical properties with which to incorporate. The device described here is a computer-controlled, motorized endoscopic grasper capable of applying surgically relevant levels of force to tissue in vivo and measuring the tissue's force-deformation properties.

Abdomen↗
PubMed1997

Retrometabolic approaches for drug design and targeting.

Retrometabolic drug design approaches incorporate targeting and metabolic considerations into the drug design process and represent a novel, systematic methodology for the design of safe, localized compounds. Two major design concepts aimed to increase the therapeutic index (the activity/toxicity ratio) of drugs were developed. Chemical delivery systems (CDS) are primarily used to allow targeting of the active biological molecules to specific target sites or organs based on predictable enzymatic activation. Brain-targeted delivery of different agents like estradiol or AZT was successfully achieved, and recent progresses include delivery of peptides using a complex strategy designated as molecular packaging. Sequential site- and stereospecific enzymatic activation of oxime/alkoxime precursors of beta-adrenergic antagonists allows their eye targeted delivery. Soft drug approaches are used to design new drugs by building in the molecule, in addition to the activity, the most desired way in which the molecule is to be deactivated and detoxified subsequent to exerting its biological effects. Many examples are available to illustrate soft drug design, e.g., soft anticholinergics, soft b-blockers, soft antiinflammatory steroids. Special computer programs were developed that starting from a lead compound generate complete libraries of possible soft analogs and then help ranking these candidates based on molecular size/shape, electronic properties, predicted solubility/partition properties, and atomic charge distributions. Recent developments in the field are presented in a supplement to this issue.

Drug Delivery Systems↗
PubMed1987

Characterization of penile erectile states using external computer-based monitoring.

The states of penile erection have not been quantified to establish their relationship to intracorporal fluid pressure and to soft tissue constraint. Computer-based circumferential rigidity sensing during erectile cycles now permits circumferential size and rigidity characterization. Measurements during dynamic infusion cavernometry and cavernosography relate intracorporal pressure and axial rigidity to circumference and circumferential rigidity characterization. Tumescence/rigidity coupling and tissue elastic contributions are identified from the combined data.

Compliance↗
PubMed1989

Trismus and multifocal soft tissue ossification. A presentation of fibrodysplasia ossificans progressiva?

A 21-year-old female patient presented with trismus, initially diagnosed as related to pericoronitis. Computed tomography demonstrated heterotopic soft tissue ossification involving both medial pterygoids which was later followed by similar features in the submandibular muscles and right quadriceps. A variant of fibrodysplasia ossificans progressiva was considered the likeliest diagnosis. The computed tomographic features of the condition and the importance of early diagnosis are stressed.

Adult↗
PubMed1994

Blood flow measurement in extremity soft tissue sarcoma with technetium-99m hexamethyl-propyleneamineoxime and single photon emission computed tomography.

Blood flow measurements were made in 28 patients with soft tissue sarcoma of the extremities to investigate the prognostic significance of tumour vascularity. Four patients with benign tumours also underwent blood flow measurement. Mean and maximum tumour blood flow was calculated from technetium-99m hexamethyl-propyleneamineoxime uptake measured using single photon emission computed tomography (SPECT), tumour volume measured from SPECT transaxial image reconstructions and cardiac output assessed with Doppler ultrasonography. Twenty-seven malignant lesions and one benign tumour showed increased uptake of isotope relative to surrounding tissues. Mean sarcoma blood flow varied between 1 and 33 ml per 100 ml tumour per min, and maximum flow between 5 and 57 ml per 100 ml per min. Fourteen patients developed progressive disease during the first year of follow-up. Eight of 11 patients with a high isotope uptake ratio, eight of 12 with a high mean blood flow and eight of 14 with a high maximum blood flow relative to the respective medians for the series showed disease progression.

Adult↗
PubMed2001

Urinary calculi on computed radiography: comparison of observer performance with hard-copy versus soft-copy images on different viewer systems.

OBJECTIVE: The purpose of this study was to compare observer performance for detecting urinary calculi using abdominal computed radiography with hard-copy versus soft-copy images and with a high-resolution video monitor versus a liquid-crystal-display (LCD) monitor. MATERIALS AND METHODS: We compared observer performance for detecting urinary calculi using three sets of radiographs-hard-copy images, soft-copy images displayed on a LCD monitor (1280 x 1024 bits), and soft-copy images displayed on a high-resolution video monitor using receiver operating characteristic curve analysis with a continuous rating scale. Computed radiography was archived with a 2140 x 1760 pixel resolution and a 10-bit depth. The selected data set included 62 images: 27 images showing proven urinary calculi smaller than 6 mm and three in number, and 35 images containing no proven abnormalities. Eleven radiologists (three genitourinary radiologists and eight general radiologists) participated in the study. Interpretations of three sets of randomly distributed radiographs were performed individually in three separate sessions at 1-week intervals. RESULTS: No statistically significant differences were found in the area under the receiver operating characteristic curve for detecting urinary calculi or in the interpreting times between soft-copy and hard-copy images; the mean areas under the receiver operating characteristic curve of hard-copy images, soft-copy images displayed on an LCD monitor, and soft-copy images displayed on a high-resolution video monitor were 0.579, 0.610, and 0.732, respectively. However, soft-copy images showed relatively improved diagnostic accuracy among less experienced radiologists (p < 0.05). CONCLUSION: For detecting urinary calculi, soft-copy images offered a diagnostic accuracy similar to or slightly more accurate than that of hard-copy images obtained in a laser-printed film-based environment. The diagnostic performance with soft-copy images viewed on an LCD monitor was comparable to that of soft-copy images viewed on a high-resolution video monitor.

Data Display↗
PubMed1993

Soft-tissue injuries related to use of the computer keyboard. A clinical study of 53 severely injured persons.

We studied 53 disabled keyboard operators who complained of pain in the forearms, elbows, wrists, shoulders, and hands. Passive wrist flexion and dorsiflexion impairment to less than 70 degrees due to myofascial shortening associated with an increase in forearm muscle pain on palpation was a useful clinical indicator of injury. Isometric muscle testing was useful in detecting injury to specific muscles. Ligamentous hypermobility of finger joints (72%) and harmful inefficient keyboard styles (intrinsic ergonomic factors) were noted, videotaped, and analyzed. Changes in the workstation (extrinsic ergonomic factors) alone may not be adequate treatment. Individual intrinsic ergonomic factors must also be recognized, addressed, and corrected by a combination of physical therapy, conditioning, technique retraining, education, and counseling. A taxonomy of keyboard technique is proposed as an aid to recognizing potentially harmful postures.

Adult↗
PubMed1984

[The value of computed tomography in the diagnosis of the rotator cuff tears and bone and soft tissue tumors].

This report consists of 2 parts. Part I: The usefulness of computed tomography (CT) in the diagnosis of rotator cuff tear was assessed. The rotator cuff could not be visualized in detail by CT unless introduction of contrast material into the joint cavity was performed. CT arthrography was performed on 21 cases of rotator cuff tears. The most detailed information was obtained when a relatively low concentration of contrast material (3.25% Angiografin) was filled in the joint cavity, and when the shoulder joint was rotated to the maximum outwards at the side. CT arthrography proved to be the most reliable method for assessing the extent and portion of the rotator cuff tears, so that it demonstrated conclusive evidence of diagnosis and management in 89% of patients studied. Part II: The usefulness of CT in the diagnosis of bone and soft tissue tumors was assessed. CT examination provided unique preoperative information which could imagine a more precise histological characteristics and anatomical localization of the lesion. Contrast enhancement (CE), when used, proved to be helpful in predicting the nature of tumors. The CE by intra-arterial infusion, or intravenous bolus injection of contrast material during the scan was more useful than that by intravenous drip infusion of the material. The information regarding change of tumor size, CT number and CE were appropriate indicators which directly corresponded to responsiveness of the tumor to the chemotherapy and radiotherapy performed. Preoperative ABC classification of the tumor by information regarding its size, location, definition and anatomical relation of tumors to vital structures (neural, vascular, and visceral) was done by using CT. The classification clearly corresponded to the status of patients regarding the treatment required for the patients.

Adolescent↗
PubMed1984

Power and radius changes induced in soft contact lens systems by flexure.

We have developed a computer program which allows analysis of soft contact lens flexure without assuming a priori that the posterior surface of the lens aligns with the central anterior cornea. Such analysis leads to the conclusion that thin low-minus lenses entrap tear layers of low volume (about 5.5 microliter) and minimum power, whereas low-plus lens systems can develop tear layers of greater volume (about 9.5 microliter), and significant power (about -2.00 D). The later finding supports clinical impressions that plus lenses "lose" power when placed on the eye. In some cases our data suggest that the lens posterior surface closely aligns with the anterior cornea, whereas in other cases such alignment is unlikely. It also appears that mathematical models for the simultaneous flexure of front and back radii of soft lenses may be described for specific lens designs. This current study suggests that delta r2 congruent to 2 delta r1 describes the relation for low-plus lenses, and delta r2 congruent to 0.75 delta r1 is the relation for low-minus lenses.

Contact Lenses, Hydrophilic↗