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PubMed1993

Computed tomography imaging in children with head trauma: utilization and appropriateness from a quality improvement perspective.

Computed tomography (CT) imaging plays an important role in the acute evaluation and management of children with head trauma. When routine quality improvement (QI) meetings with representatives from the Children's Hospital radiology and emergency departments revealed disagreement regarding the utilization and appropriateness of CT in children presenting with head trauma, an interdepartmental QI team was formed to address this issue. Because formal criteria for obtaining CTs for head trauma were unavailable, internal institutional criteria were developed by consensus after literature review. Contrary to perceptions of some staff members, the majority (95%) of children who received CT met at least one of the established criteria over a one-year study period. There was little relationship between the presence of criteria and abnormal CT results, but decisions whether to admit patients to the hospital or to send them home were influenced by CT results. Follow-up studies suggested that patients who were discharged home with a normal CT or no CT had uniformly good outcomes.

Boston↗
PubMed1994

Computerized detection of pulmonary nodules in computed tomography images.

RATIONALE AND OBJECTIVES: Interpretation of computed tomographic (CT) scans of the lungs is a time-consuming task that involves visual correlation of possible nodules in one section with those in contiguous sections to distinguish actual nodules from blood vessels. Thus, the authors are developing automated methods to detect nodules on CT images of the thorax. METHODS: The computerized technique uses various computer-vision techniques and a priori information of the morphologic characteristics of pulmonary nodules. In each section, the external thoracic wall and lung boundaries are detected, and the features within the lung boundaries are subjected to gray-level thresholding operations. By analyzing the relationships between features arising at different threshold levels with respect to their shape, size, and location, each feature is assigned a likelihood of being a nodule or a vessel. Features in adjacent sections are compared to resolve ambiguous features. Detected nodule candidates are displayed in three dimensions within the lung. RESULTS: The system provided a sensitivity of 94% for nodule detection and an average of 1.25 false-positive results per case. CONCLUSIONS: Continued development of an automated method for detecting pulmonary nodules in CT scans is expected to aid radiologists in the task of locating nodules in three dimensions.

Artificial Intelligence↗
PubMed1984

Three-dimensional dynamic x-ray-computed tomography imaging of stomach motility.

The dynamic spatial reconstructor (DSR), an x-ray-computed, tomography-based imaging machine, scans a cylindrical volume up to 39 cm in transaxial diameter and 21.5 cm in axial height with scan repetition rate up to 60 per second. We applied this technique to three dogs in order to investigate the accuracy with which stomach shape, dimensions, and motility can be measured. Single peristaltic waves of one dog's stomach filled with air and two other dogs' stomachs filled with different volumes of contrast-enhanced semisolid meals (10% Gastrografin) were scanned at 2-s intervals at scan apertures between 0.011- and 1-s duration. On completion of the scan sequence, images of oblique sections perpendicular to the local long axis of the stomach fundus, corpus, and antrum were computed from the DSR scan data. Measurements of differential motion of defined points on the stomach wall surface, propagation velocities, acceleration, and amplitudes of peristalsis as well as gastric volume determinations were made. This approach overcomes problems of superposition and ambiguity inherent in projection imaging. Measurements of the volumes of ingested first meal were accurate to within 1.5% (of the actual volume of solid food introduced into the stomach) using a 0.40-s scan aperture. Wall motion could be detected with an SEE of 1.5 mm (pixel size used was 1.4 mm) using a 0.40-s scan aperture.

Animals↗
PubMed2002

Interpretation of computed tomography imaging of the eye and orbit. A systematic approach.

Computed tomography (CT) has revolutionised the diagnosis and management of ocular and orbital diseases. The use of thin sections with multiplanar scanning (axial, coronal and sagittal planes) and the possibility of three-dimensional reconstruction permits thorough evaluation. To make the most of this technique, users must familiarize themselves with the pertinent CT principles and terminology. The diagnostic yield is optimal when the ophthalmologist and radiologist collaborate in the radiodiagnostic workup. In this article we describe a systematic approach to the interpretation of ocular and orbital CT scans.

Eye↗
PubMed2001

Evaluation of substernal goiters using computed tomography and MR imaging.

Computed tomography and MR imaging are valuable techniques for determining the presence and extent of substernal goiters, their impingement on adjacent structures in the neck and chest, and whether mediastinal masses are thyroidal in origin. This article discusses the advantages and disadvantages of each technique and the radiologic characteristics of substernal goiters. Radiographic examples of both techniques are included to illustrate common clinical settings. Finally, suggestions for choosing which patients will benefit from scanning and which technique will safely provide the maximum information in various clinical settings are discussed.

Goiter↗
PubMed1997

Quantification of pulmonary emphysema from lung computed tomography images.

A texture-based adaptive multiple feature method (AMFM) for evaluating pulmonary parenchyma from computed tomography (CT) images is described. This method incorporates multiple statistical and fractal texture features. The AMFM was compared to two previously published methods, namely, mean lung density (MLD) and the lowest fifth percentile of the histogram (HIST). First, the ability of these methods to detect subtle differences in ventral-dorsal lung density gradient in the prone normal lung was studied. Second, their abilities to differentiate between normal and emphysematous whole lung slices were compared. Finally, regional analyses comparing normal and emphysematous regions were performed by dividing the lungs. In the CT slices into six equal regions, ventral to dorsal, and analyzing each region separately. The results demonstrated that the AMFM could separate the ventral from the dorsal one-third of the normal prone lung with 89.8% accuracy, compared to an accuracy of 74.6% with the MLD and 64.4% with the HIST methods. The normal and emphysematous slices were separated on a global basis with 100.0% accuracy using the AMFM as compared to an accuracy of 94.7% and 97.4% using the MLD and HIST methods, respectively. The regional normal and emphysematous tissues were discriminated with an average accuracy of 97.9%, 89.9%, and 99.1% with the AMFM, MLD, and HIST methods, respectively. The three methods and the pulmonary function tests in the normal and emphysema groups were poorly correlated. Quantitative texture analysis using adaptive multiple features holds promise for the objective noninvasive evaluation of the pulmonary parenchyma.

Humans↗
PubMed2003

Measurement of femoral anteversion by biplane radiography and computed tomography imaging: comparison with an anatomic reference.

RATIONALE AND OBJECTIVES: The ability of biplane radiography and standard computed tomography (CT) imaging techniques to measure accurately the human femoral anteversion was evaluated and compared with an anatomic reference: the osteometric method. METHODS: Femoral anteversion of 10 normal adult cadaveric human femora were determined using a standardized anatomic measurement method (the anatomic reference) and the 2 selected common imaging techniques (biplane radiography and CT). RESULTS: On average, anteversion measurements using biplane radiography were 21/2 times greater in magnitude than measurements using the anatomic reference (absolute mean difference, 13.5 degrees; P = 0.004). In contrast, the discrepancy between CT and anatomic reference measurements was notably less and not statistically significant (absolute mean difference, 2.8 degrees; P = 0.351). In addition, biplane radiography demonstrated greater inter- and intrarater variability than CT imaging for repeated measurements of the same bone specimens. CONCLUSIONS: Compared with the anatomic reference, CT imaging was an accurate and valid technique for measuring the femoral anteversion. In contrast, biplane radiography demonstrated significant inconsistencies in the measurement of this anatomic parameter.

Adult↗
PubMedDate not supplied

Registered computed tomography images as an alternative to postimplantation magnetic resonance imaging in the assessment of subthalamic electrode placement.

Magnetic resonance imaging (MRI) after implantation of electrodes in the subthalamic nuclei is currently performed at a number of sites, but a recent adverse incident and changes in MRI technology may heighten safety concerns. In this report, it is demonstrated that given whole-head image data, registration of postimplantation computed tomography to preimplantation MRI can enable verification of the position of electrodes to an accuracy of 2 mm. This registration technique can remove the need for potentially risky postoperative MRI.

Electric Stimulation Therapy↗
PubMed2006

Differentiation between cholesteatoma and inflammatory process of the middle ear, based on contrast-enhanced computed tomography imaging.

OBJECTIVE: To assess the usefulness of delayed post-contrast computed tomography (CT) examination for the detection of residual or recurrent cholesteatoma after canal wall up tympanoplasty. STUDY DESIGN AND SETTING: This prospective, non-randomized study, set within an academic medical centre, included 17 consecutive patients who had undergone canal wall up tympanoplasty for cholesteatoma, with possible recurrence. Pre-contrast CT scans and delayed post-contrast images were compared with second look surgical findings. RESULTS: A residual or recurrent cholesteatoma was found in eight of the 17 patients at revision surgery and was correctly diagnosed on post-contrast CT images in six patients (75 per cent). In the two misdiagnosed cases, cholesteatoma pearls smaller than 2.5 mm were not seen on post-contrast CT. The sensitivity of the imaging test was 75 per cent, the specificity was 60.1 per cent, the positive predictive value was 88.1 per cent and the negative predictive value was 81.8 per cent. CONCLUSION: Computed tomography with delayed post-contrast images is a sensitive imaging modality for the detection of residual cholesteatoma. If proven reliable, this method of non-invasive imaging could spare the patient unnecessary revision surgery.

Adult↗
PubMed1993

Size of cortical bone and relationship to bone mineral density assessed by quantitative computed tomography image segmentation.

RATIONALE AND OBJECTIVES: The accuracy of the measurement of the size of cortical bone on computed tomography (CT) images of human vertebrae was evaluated using an automated contour detection and segmentation procedure. METHODS: Forty human lumbar vertebrae were scanned using 8-mm slices and an automated detection for definition of trabecular and cortical region of interest. The vertebrae were embedded in a polyester resin and 8-mm-thick midvertebral specimens were excised using a diamond circular saw. Contact radiographs of these specimens were performed and, after photograph magnification, the cortical area was measured using computerized planimetry. RESULTS: Cortical area measured on CT images was highly correlated with the area measured by planimetry on the specimens (r = .91; P < .001) with, however, a systematic over-estimation. A significant relationship was found between density and width of the cortex (r = .56; P < .001). CONCLUSIONS: Computed tomography is able to assess the size of cortical bone in human vertebrae, but a threshold detection algorithm, as used in the current study, is not adequate to obtain the precise anatomic dimensions.

Aged↗
PubMedDate not supplied

Multiplanar reconstructed computed tomography images improves depiction and understanding of the anatomy of the frontal sinus and recess.

AIMS: The use of multiplanar reconstructed computed tomography (CT) images of frontal recess and sinuses was assessed with regard to depiction and understanding of anatomy and effect on surgical approach. MATERIALS AND METHODS: Three otorhinolaryngologists and one radiologist read CT scans of 43 patients referred for routine paranasal sinus scans. Spiral (helical) CT scans were obtained and coronal and parasagittal reconstructions were imaged. Three hundred forty-two readings were analyzed. The scans were assessed in the coronal plane and then in the parasagittal plane. The images were assessed for (i) Bent and Kuhn classification of frontal ethmoidal sinus air cells, (ii) size of frontal sinus ostium (assessed as unsure, normal, small, or large), (iii) use of parasagittal scans regarding additional understanding of the anatomy with particular reference as to how the agger nasi cell and frontal ethmoidal cells were arranged in a three-dimensional space, and (iv) if the parasagittal scan and subsequent three-dimensional picture created altered the surgical approach. The first two criteria were assessed in the coronal plane and then in the parasagittal plane. RESULTS: There was no statistically significant difference between the Bent and Kuhn classification of frontoethmoidal cells on coronal and reconstructed parasagittal images (t-test; p > 0.05). The parasagittal scans were significantly better than the coronal scans for identifying and assessing the size of the frontal sinus ostium (p < 0.001; chi-square test). Assuming an intraobserver change rate (repeat error) of 10% on CT scan observations, an exact binomial test was performed on S-PLUS, which showed that there was a significant (p < 0.001) proportion of observers who changed their rating after looking at the parasagittal scan. There also was significant improvement in observers' abilities to identify and classify the size of the frontal ostium as reflected by the number of observers who changed from being unsure on the coronal scans to sure on the parasagittal scans. Observers felt that the parasagittal scans improved their three-dimensional understanding of the anatomy of the frontal recess by 58% on a 10-point Lickert scale. In 55% of these observations, the surgical plan was altered by a mean of 70.2% on a 10-point Lickert scale based on additional information obtained by viewing the parasagittal scans. CONCLUSIONS: The three-dimensional understanding of the frontal recess is improved greatly by using both coronal and parasagittal reconstructed images as compared with coronal images alone. This had important implications on the planning of the surgery in the frontal recess.

Frontal Sinus↗
PubMed1992

Staging of cervical cancer: comparison between magnetic resonance imaging, computed tomography and pelvic examination under anesthesia.

A prospective study was undertaken to compare magnetic resonance imaging (MRI) with computed tomography (CT) and examination under anesthesia (EUA) in staging cervical carcinoma, with special emphasis on parametrial status. Twenty patients with carcinoma of the cervix, in whom the extent of the disease was surgically confirmed, were analyzed by MRI, CT and EUA. The tumor size estimated by MRI correlated well (r = 0.79, p < 0.001) with those obtained by histopathologic measurement of the surgical specimen. Neither clinical examination nor CT could precisely estimate tumor size. The overall accuracy rate of MRI in staging carcinoma of the cervix was 75%, compared with 32% for CT staging and 55% for clinical staging. The accuracy rate of these modalities for parametrial status was 90% for MRI, 55% for CT and 82.5% for EUA. MRI accurately excluded all 20 patients with pelvic side wall, bladder and rectal involvement. In conclusion, MRI is superior to CT and EUA in assessment of the parametrium (90% vs 55% vs 82.5%, p < 0.005). From MRI, tumor size can be estimated precisely. Although a larger scale study comparing MRI and CT is needed to determine their roles, both should help in the diagnosis and selection of proper treatment for cervical carcinoma. Our preliminary report agrees with previous reports that MRI is promising and indispensable. MRI should be routinely used in conjunction with clinical staging to determine appropriate therapy in patients with cervical carcinoma.

Adult↗
PubMed1986

[Performance of gamma camera collimators used for single photon emission computed tomography imaging with 123I-isopropyl iodoamphetamine].

123I Produced by 124Te(p, 2n)123I reaction is contaminated with 124I (less than 5%) and 126I (less than 0.3%). High energy photons from these mixed radioiodine compromise seriously image quality due to scattered photons and to septal penetration in the collimator. Four collimators of LEAP (for low energy all purpose), LEHR (for low energy high resolution), MESI (for medium energy made by Siemens) and MENU (for medium energy made by nuclear technology) mounted on a rotating gamma camera (Siemens, ZLC-7500), were examined in order to select a suitable collimator for 123I SPECT (single photon emission computed tomography) imaging. Sensitivities were measured with a plane source (5 X 5 X 0.5 cm) at the collimator face and distances from 2 to 30 cm in air. And, spatial resolutions in FWHM (full width at half maximum) and FWTM (full width at tenth maximum) were determined from line spread functions with planar and SPECT imaging. From the comparison of collimator performances with 99mTc and 123I, both collimators for low energy were not useful for 123I imaging. In other two collimators for medium energy, however, apparently the effect of septal penetration by the higher energy photons were also recognized, MENU with high geometrical resolution was more suitable for 123I SPECT imaging compared with MESI. And, it is important to perform the SPECT imaging with radius as short as possible.

Amphetamines↗
PubMed2006

Early invasive cervical cancer: tumor delineation by magnetic resonance imaging, computed tomography, and clinical examination, verified by pathologic results, in the ACRIN 6651/GOG 183 Intergroup Study.

PURPOSE: To compare magnetic resonance imaging (MRI), computed tomography (CT), and clinical examination for delineating early cervical cancer and for measuring tumor size. PATIENTS AND METHODS: A 25-center study enrolled 208 patients with biopsy-proven invasive cervical cancer for MRI and CT before attempted curative radical hysterectomy. Each imaging study was interpreted prospectively by one onsite radiologist and retrospectively by four independent offsite radiologists, who were all blinded to surgical, histopathologic, and other imaging findings. Likelihood of cervical stromal and uterine body involvement was rated on a 5-point scale. Tumor size measurements were attempted in three axes. Surgical pathology was the standard of reference. RESULTS: Neither MRI nor CT was accurate for evaluating cervical stroma. For uterine body involvement, the area under the receiver operating characteristic curve was higher for MRI than for CT for both prospective (0.80 v 0.66, respectively; P = .01) and retrospective (0.68 v 0.57, respectively; P = .02) readings. Retrospective readers could measure diameter by CT in 35% to 73% of patients and by MRI in 79% to 94% of patients. Prospective readers had the highest Spearman correlation coefficient with pathologic measurement for MRI (r(s) = 0.54), followed by CT (r(s) = 0.45) and clinical examination (r(s) = 0.37; P < .0001 for all). Spearman correlation of multiobserver diameter measurements for MRI (r(s) = 0.58; P < .0001) was double that for CT (r(s) = 0.27; P = .03). CONCLUSION: In patients with cervical cancer, MRI is superior to CT and clinical examination for evaluating uterine body involvement and measuring tumor size, but no method was accurate for evaluating cervical stroma.

Adenocarcinoma↗
PubMed2001

Neuropsychological outcome in relation to the traumatic coma data bank classification of computed tomography imaging.

The Traumatic Coma Data Bank (TCDB) classification of CT (computed tomography) scan has been related to the general outcome and intracranial pressure evolution. Our aim was to analyse the relationship of this classification with neuropsychological outcome and late indices of ventricular dilatation. Fifty-seven patients with a moderate or severe head injury (mean admission Glasgow Coma Scale Score, 7.7) were studied from 122 consecutive cases. There were 49 males and 8 females (mean age, 27.7 years). Subjects were classified into TCDB categories on the basis of their most serious acute CT scan finding. From the last control CT scan image, performed at a mean of 6.12 months postinjury, several measures of ventricular dilatation were calculated. Neuropsychological assessment at 6-month included tests of verbal and visual memory, visuoconstructive functions, fine motor speed, and frontal lobe functions. Patients with diffuse injury type I showed better neuropsychological outcome than patients with more severe diffuse injuries and those with mass lesions. Within the diffuse injury groups, the degree of diffuse damage was related to measures of verbal memory and attention and cognitive flexibility. Ventricular enlargement was more evident in patients with mass lesions and it decreased in the remaining groups as the severity of diffuse injury diminished. These results show that there is a relationship between acute intracranial lesion diagnosis according to TCDB classification and neuropsychological results and ventricular dilatation indices at 6 months postinjury.

Adolescent↗
PubMed1988

Noninvasive imaging for staging of prostate cancer: magnetic resonance imaging, computed tomography, and ultrasound.

The diagnosis of prostate carcinoma by imaging is still fraught with problems, even with the advent of highly sophisticated techniques. Despite enthusiastic preliminary reports, no one imaging method reliably screens for this condition. The staging of prostate carcinoma is feasible, but the best imaging method remains a subject of debate. The transabdominal sonographic approach lacks the resolution required for detailed intraglandular anatomic delineation. The transrectal sonographic approach excels in guiding needle biopsy and in evaluating transcapsular and seminal vesicle extension of known tumors. Computed tomography lags behind other tomographic imaging modalities in its accuracy for local tumor staging, but it is excellent, although nonspecific, in the detection of lymph node enlargement. Magnetic resonance detects abnormalities in the prostate in a high percentage of cases but is nonspecific. However, it can stage prostate carcinoma and detect lymphadenopathy reliably.

Humans↗