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The demonstration that DNA molecules can act as parallel processors to solve hard problems has excited interest in the possibility of developing molecular computers based on recombinant DNA techniques.
RATIONALE AND OBJECTIVES: This study compared the educational effectiveness of an interactive tutorial with that of interactive computer-assisted instruction (CAI) and determined the effects of personal preference, learning style, and level of training. MATERIALS AND METHODS: Fifty-four medical students and four radiology residents were prospectively, randomly assigned to receive instruction from different sections of an interactive tutorial and an interactive CAI module. Participants took tests of factual knowledge at the beginning and end of the instruction and a test of visual diagnosis at the end. They completed questionnaires to evaluate their preferred learning styles objectively and to elicit their subjective attitudes toward the two formats. Mean test scores of the tutorial and CAI groups were compared by means of analysis of covariance and two-tailed repeated-measures F test. RESULTS: Both the tutorial and CAI groups demonstrated significant improvement in posttest scores (P < .01 and P < .01, respectively) with the tutorial group's mean posttest score marginally but significantly higher (32.84 vs 28.13, P < .001). There were no significant interaction effects with participants' year of training (P = .845), objectively evaluated preferred learning style (P = .312), subjectively elicited attitude toward learning with CAI (P = .703), or visual diagnosis score (tutorial, 7.61; CD-ROM, 7.75; P = .79). CONCLUSION: Interactive tutorial and optimal CAI are both effective instructional formats. The tutorial was marginally but significantly more effective at teaching factual knowledge, an effect unrelated to students' year of training, learning style, or stated enjoyment of CAI. The superiority of the tutorial is expected to increase when it is compared with commercially expedient CAI modules.
This case report describes the use of retrospectively ECG-gated multislice spiral computed tomography (MSCT) for evaluation of lesion severity in a patient with relevant left main stenosis by visual analysis of the coronary angiogram. For further diagnostic evaluation the patient underwent intravascular ultrasound (IVUS) imaging, which showed a maximal 30% area stenosis, and MSCT, which demonstrated a maximal 48% area stenosis. MSCT was useful in this case to defer cardiac surgery and might be used as a noninvasive alternative to IVUS imaging in case of doubtful lesion severity.
PURPOSE: In this retrospective study, we evaluated isolated blowout fractures of the orbital floor by region-of-interest measurements from coronal computed tomography (CT) scans and their relationship to ophthalmologic findings. PATIENTS AND METHODS: Fracture area and volume of displaced tissue of blowout fractures in 38 patients were measured from coronal CT scans. Measurement was performed by identifying distances (for area calculation) of the fracture and identifying areas (for volume calculation) of the displaced tissue in each CT slice. The calculated data were then compared with the amount of enophthalmos, presence of diplopia, and limitation of ocular motility. RESULTS: Orbital floor area (mean +/- SD) was 5.72 +/- 1.07 cm(2); fracture area, 2.63 +/- 1.20 cm(2); and the volume of displaced tissue, 1.15 +/- 0.91 mL. The average proportion of the fracture within the orbital floor was 45.3 +/- 17.6%. Fracture area and volume of displaced tissue were significantly positively correlated with enophthalmos and diplopia and not correlated with the limitation of ocular motility. For enophthalmos of 2 mm or greater, mean fracture area (mean +/- SD) was 4.08 +/- 1.09 cm(2) and volume of displaced tissue was 1.89 +/- 1.19 mL; for less than 2-mm enophthalmos, 1.98 +/- 0.83 cm(2) and 0.83 +/- 0.58 mL, respectively. Enophthalmos of 2 mm can be expected with 3.38 cm(2) of fracture area and 1.62 mL of displaced tissue. CONCLUSIONS: Region-of-interest measurement from coronal CT scan has an application in the assessment of patients with pure blowout fractures of the orbital floor and adds useful information in posttraumatic evaluation of orbital fractures.
The early results in the investigation of normal and pathological hearts using fast computer tomography are presented. By means of tomographic sections of cadaver hearts, it has been shown that it is possible to distinguish the ventricular cavities and individual cardiac walls by this non-invasive method. Changes in volume of the ventricles and atria due to various forms of stress are easily distinguishable. Myocardial scars can be distinguished from other circumscribed myocardial defects. The particular advantages of this method, which is non-invasive, painless and easily repeatable, do not need to be stressed. The technique adds a significant dimension to previously available non-invasive diagnostic methods, such as ultrasound echo-cardiography.
Indications for computed tomography (CT) of the musculoskeletal system, especially with the advent of 16-slice multidetector CT (MDCT), are numerous. In addition to the evaluation of the trauma patient where CT is essential when imaging complex skeletal injuries, MDCT is particularly useful in patients who have had prior surgery. In postoperative cases, metal artifact typically prohibits magnetic resonance imaging evaluation, but volume-rendering of a MDCT axial database virtually eliminates streak artifact associated with hardware. For the evaluation of masses, CT provides the ability to detect and characterize calcification, cortical disruption, and periosteal reaction. In this article, these and other indications for performance of CT of the musculoskeletal system will be discussed.
With regard to image diagnosis of inner ear anomalies, three-dimensional computed tomography (3D-CT) is useful in obtaining very realistic images that are unmatched by 2D-CT. Unlike the step scanning in the existing 2D-CT, in helical 3D-CT, scanning is performed in a spiral motion by continuously rotating the scanner and moving the table along the body axis at a constant speed. As a result, data obtained by this CT are continuous and very smooth curves can be obtained. Among the data, the CT attenuation determines the quality of the final 3D images. In the present paper, the usefulness of 3D-CT was investigated in a case with Mondini-type inner ear malformation.
Arterial connection between the left and right kidneys is extremely rare. Only eight cases of such anomalous conditions have been reported in the world literature and all were confirmed by invasive angiography or dissection. We report a patient with this vascular anomaly clearly demonstrated by 16-slice multidetector computed tomography.
Previous research on computer games has tended to concentrate on their more negative effects (e.g., addiction, increased aggression). This study departs from the traditional clinical and social learning explanations for these behavioral phenomena and examines the effect of personality, in-game reinforcement characteristics, gender, and skill on the emotional state of the game-player. Results demonstrated that in-game reinforcement characteristics and skill significantly effect a number of affective measures (most notably excitement and frustration). The implications of the impact of game-play on affect are discussed with reference to the concepts of "addiction" and "aggression."
We compared gated magnetic resonance imaging (MRI) and dynamic computed tomography (DCT) with two-dimensional cardiac ultrasound (ECHO) to assess differences in diagnostic information. Magnetic resonance imaging was performed in 41 patients; ECHO in 36, and DCT in 28 patients with various pathologic conditions. We measured the left and right ventricular (LV, RV) long and short axes (LA, SA), LV free wall and septal thickness (WT, ST) at end systole (ES) and end diastole (ED) on the apical four-chamber view (ECHO) or appropriate transaxial slice (MRI, DCT) on a subset of 14 patients. Paired-sample analysis of these three techniques, in this preliminary data, yields statistically different results as follows: LV SA: MRI versus ECHO at ED and ES (P less than 0.001 and 0.005); WT: MR versus ECHO at ES (P less than 0.002); CT versus ECHO at ED and ES (P less than 0.05 and 0.01); ST: MRI versus ECHO at ED and ES (P less than 0.001), and CT versus ECHO at ES (P less than 0.05). Thus, CT and MRI yield similar quantitative data, but both differ in varying degree from ECHO measurements. Differential accuracies and utilities of these techniques warrant further careful investigation.
This paper describes a simple program that uses a digitizing device to enter DNA sequences directly from autoradiographs into a computer.
The program DNAGEL is used to determine the size of DNA fragments run on agarose or polyacrylamide gels. The positions of the bands are read from gel photographs by means of a digitizer. Standard curves are calculated by the method of Southern (1979). The bands, as they are measured, are reproduced on the screen so that erroneous input can be recognized and corrected immediately. Similarly the estimated fragment sizes are printed in a table in the same relative positions as the bands on the gel. This makes it especially easy to relate fragment sizes with the bands on the gel picture. As an additional function the calculated positions of bands can be displayed on the screen. The program DNAGEL is written in APPLESOFT BASIC, suitable for APPLE II computers with 48K memory connected to a monitor, printer and a HOUSTON graphics tablet.
OBJECTIVE: To compare the diagnostic accuracies of Lipiodol computed tomography (CT) and helical biphasic CT as preoperative imaging modalities for hepatocellular carcinoma (HCC). SUMMARY BACKGROUND DATA: Lipiodol CT after digital subtraction angiography has long been used as a highly sensitive imaging modality for HCC. The recent advent of helical CT has allowed scanning the entire liver during both the arterial and portal venous phase of contrast enhancement. METHODS: The authors analyzed data from 164 patients who underwent hepatic resection for HCC to calculate the sensitivity and specificity of these modalities. Findings of intraoperative ultrasonography followed by histologic confirmation were set as the gold standard. RESULTS: Although sensitivity decreased with both modalities as tumors became small and well differentiated, helical CT showed a higher sensitivity than Lipiodol CT in detecting well-differentiated HCC nodules smaller than 2 cm. In contrast, Lipiodol CT was superior to helical CT for the detection of small but moderately to poorly differentiated nodules. The overall sensitivity of helical CT was higher than that of Lipiodol CT. These findings suggest that helical CT is superior in delineating early HCC, whereas Lipiodol CT is specific to the detection of intrahepatic metastases. In terms of specificity, helical CT was superior to Lipiodol CT. CONCLUSIONS: Helical CT and Lipiodol CT are complementary modalities. At present, helical biphasic CT does not obviate the need for invasive techniques such as angiography and Lipiodol CT as preoperative examinations for HCC.
The roles of noncontrast computed tomography (NCCT) and CT angiographic/CT perfusion (CTA/CTP) imaging in the rapid triage of clinically suspected hyperacute stroke patients to appropriate therapy is reviewed. Contraindications to thrombolysis include NCCT hemorrhage (absolute) and significant parenchymal hypodensity (relative). The sensitivity of NCCT for early (<6 h) stroke detection, higher than that of conventional magnetic resonance imaging, is improved further by using nonstandard window and level review settings. CTA/CTP is fast and convenient, adding approximately 10 min to the NCCT examination. CTA/CTP's accuracy in diagnosing ischemia and localizing thrombus to proximal or distal intracranial vessels far exceeds that of clinical examination (including National Institutes of Health stroke scale use), facilitating triage of appropriate candidates to intra-arterial thrombolysis. The size of the ischemic CTP hypodensity (proportional to reduced cerebral blood volume) predicts final infarct volume and clinical outcome; its location can guide the decision to perform intra-arterial thrombolysis, intravenous thrombolysis, or other treatment.
Facial fractures that result in lacrimal drainage obstruction may add complexities to lacrimal surgery. The role of preoperative assessment of lacrimal obstruction after facial fractures using computed tomography (CT) or CT dacryocystography was assessed in this study. Consecutive patients (n = 13) with symptomatic lacrimal obstruction after facial fractures underwent radiologic evaluation prior to lacrimal surgery. The first three patients underwent CT alone. The subsequent 10 patients underwent CT dacryocystography, in which radio-opaque dye was instilled into the lacrimal sac prior to CT. Radiographic findings pertinent to surgical management were present in 11 of the 13 patients and included alterations in bony anatomy, plates or wires adjacent to the lacrimal sac, nasal septal deviation, sinusitis, anterior ethmoid air cells, and anteriorly located middle turbinates. CT or CT dacryocystography prior to lacrimal surgery in patients with previous facial fractures may facilitate preoperative planning and intraoperative execution. It is recommended that the cost of these studies be minimized by adherence to streamlined protocols widely used in sinus CT.
This short article describes one hospital's efforts to develop a computer-based instruction program for critical care nurses who care for patients undergoing increased intracranial pressure monitoring.
We report imaging findings in five patients who had sudden cardiac arrest during contrast-enhanced computed tomography (CT). We observed strikingly dense abdominal veins, variable degrees of arterial enhancement, and poor abdominal visceral enhancement. Comparison with a control group of 30 patients revealed a statistically significant increase in mean enhancement of the abdominal veins (including the inferior vena cava, bilateral renal veins, and major tributaries of the hepatic vein) (Kruskal-Wallis test, P< 0.05). These patients lacked any clear cause of cardiac arrest, and the arrest may have been related to an adverse reaction to contrast medium. Despite resuscitation, two patients died and three convalesced. In summary, sudden cardiac arrest is characterized by "dense abdominal veins" on CT in the absence of the cardiac pump function. This effect was presumably the result of forced reflux and stagnation of contrast medium in the abdominal veins without any dilution with the circulating blood, leading to a markedly dense appearance of these venous structures.
OBJECTIVE: We conducted this study to correlate computed tomography (CT) images with the complications induced by CT-guided percutaneous ethanol injection (PEI) for the treatment of hepatocellular carcinoma (HCC). METHODS: Twenty-two patients with ultrasonographically unreachable HCC were treated with CT-guided transthoracic PEI. The procedures and the CT findings were recorded to correlate with the various complications of PEI. RESULTS: After the ethanol injection, 3 patterns of CT images were identified according to the distribution of ethanol (ie, intratumoral, extrahepatic, and intrahepatic patterns). The intrahepatic pattern was further classified as the branch, tubular, and infiltrative types. During the follow-up period, 3 patients developed biliary stricture, portal vein thrombosis, or tumor seeding. The tubular type was associated with the development of biliary stricture, whereas the branch type was related to the occurrence of portal vein thrombosis. These complications were considered to be caused by a greater amount of ethanol leakage into bile ducts or portal veins than in cases without complications (median = 17 mL vs. 0 mL, P = 0.002). CONCLUSIONS: Ethanol leakage is not uncommon when performing PEI; however, it seems to be safe when the leakage is less than 15 mL. Injection of a small amount of ethanol or monitoring by CT may be helpful in preventing the development of these complications.