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PubMedDate not supplied

Comparative morphometry of the lower lumbar vertebrae: osteometry in dry bones and computed tomography images of patients with and without low back pain.

Various factors affect the development of the vertebral canal. The dimensions of the vertebral canal and the intervertebral foramen can be altered by these factors before or after birth. Sex differences in dimensions have also been reported. When there is a stenosis of the vertebral canal or the intervertebral foramen, neural structures confined within them can be affected easily, resulting in symptoms. Using computed tomography images, we compared vertebral canal dimensions in 100 patients with low back pain and/or radiculopathy with those in 40 healthy, non-symptomatic controls. We also measured the dimensions of 275 dry bones. We found significant correlations among the variables in the live subjects. We found significant differences between patients and controls in the variables that were measured. Stenoses were more prevalent in females. Dry bone measurements showed some sex differences, and stenosis mainly in vertebrae L4, L5 and S1.

Adult↗

PubMed2007

Preoperative computed tomography imaging in the management of impacted mandibular third molars.

PURPOSE: The purpose of this study was to examine the role of preoperative computed tomography (CT) imaging of the inferior alveolar nerve (IAN) for patients at increased risk for nerve injury during mandibular third molar (M3) extraction. MATERIALS AND METHODS: To address the research purpose, the investigators enrolled a sample composed of subjects who presented for mandibular M3 extraction and had panoramic radiographic signs interpreted as being associated with an increased risk for inferior alveolar nerve injury. All subjects had preoperative CT imaging studies done to ascertain the position of the IAN with respect to M3. The predictor variable was the preoperative assessment of risk for IAN injury based on panoramic imaging. The outcome variable was the preoperative assessment of IAN injury risk after reviewing the CT studies. We documented the number of IAN injuries. Descriptive statistics were computed as indicated. RESULTS: The sample consisted of 23 patients who had bilaterally impacted wisdom teeth. The sample's mean age was 26 +/- 6 years (range: 18-48 years); 69.6% of the patients were female. After reviewing the panoramic radiographic, 80.4% of M3s were classified as having an increased risk for IAN injury. Upon examining the CT imaging, 32.6% were classified as high risk for IAN injury. After reviewing all imaging studies, 71.7% of the teeth in the sample were extracted. Intraoperative IAN visualization occurred in 21.2% of the cases. At 1 week postoperative, 3 patients had dysesthesia (9.1%); none had a permanent nerve injury. CONCLUSION: In this small series of patients, the additional information provided by 3-dimensional imaging changed the majority of patients from increased risk for nerve injury to low risk for nerve injury.

Adolescent↗

PubMedDate not supplied

Three-dimensional computed tomography imaging: its applicability in the evaluation of extensor tendons in the hand and wrist.

OBJECTIVE: The purpose of this study was to determine whether 3-dimensional (3D) computed tomography (CT) imaging with volume rendering can accurately evaluate extensor tendons in the hand and wrist. METHODS: Three-dimensional CT imaging was used to evaluate 14 cases. The location where the rupture was suspected was the wrist level in all cases. The accuracy of the image diagnosis was confirmed during surgery in 13 cases. RESULTS: Three-dimensional CT could identify all extensor tendons proximal to the metacarpophalangeal joint. In the cases with rupture, the location of the distal stump could be identified, whereas that of the proximal stump was uncertain. The tendon stump location confirmed during surgery correlated well with the images. CONCLUSIONS: This study revealed the usefulness of 3D CT imaging in defining extensor tendons proximal to the metacarpophalangeal joint. This method increased the accuracy and ease of diagnosis and was always useful in surgical planning and patient education.

Adult↗

PubMed2000

Does high-resolution computed tomography image analysis of the distal radius provide information independent of bone mass?

This study aimed to investigate the usefulness of computed tomography (CT) image analysis of the distal radius for comparing two groups of postmenopausal women matched for age and bone mineral density at both the lumbar spine and femoral neck. The first one consisted of 16 women with at least one vertebral fracture and the second consisted also of 16 women without disease affecting bone mass or bone metabolism. Eight slices were selected in each patient: four consecutive coronal slices and four consecutive axial slices. Bone texture analysis was performed using structural methods leading to the measurement of 24 features. Most of the structural variables derived from histomorphometric parameters and were measured after segmentation from a binary or a skeletonized image. Nine variables were significantly different between the two groups on axial slices: valley number, valley surface area, apparent bone volume/tissue volume (BV/TV), apparent trabecular separation, apparent trabecular number, trabecular bone pattern factor, trabecular skeletal length, node count, and node-to-node strut count. Also four variables were significantly different between osteoporotic women and controls on coronal slices: apparent BV/TV, trabecular partition, node-to-node strut count, and terminus-to-terminus strut count. In conclusion this study suggests that bone texture analysis could yield additional data on bone mass for explaining bone strength and therefore could be used for improving the prediction of fracture risk.

Absorptiometry, Photon↗

PubMed1990

Magnetic resonance imaging, computed tomography and endosonography in the local staging of carcinoma of the cervix.

Thirty-seven patients with carcinoma of the cervix were prospectively staged by examination under anaesthesia (EUA), transvaginal and transrectal ultrasound, computed tomography (CT) and magnetic resonance imaging (MRI). Pathological correlation was available for 20 patients. In the pathologically staged patients, EUA agreed with the staging in 17, understaging three patients. Endosonography agreed with the staging in 19, CT in 16 and MRI in 18 patients. For the remaining 17 patients, endosonography agreed with the EUA findings in 13, CT in 12 and MRI in 12. This study has shown that endosonography and MRI are more accurate than CT in the local staging of carcinoma of the cervix. Computed tomography was least accurate in staging early tumours and differentiating between Stage Ib and IIb disease. Lymph node involvement was detected with equal frequency by both CT and MRI. Magnetic resonance imaging was useful in identifying vaginal and bladder wall involvement and in one patient showed features due to an unsuspected early pregnancy.

Adult↗

PubMed1998

Appendicitis: the impact of computed tomography imaging on negative appendectomy and perforation rates.

OBJECTIVES: The purposes of this study were to investigate the use of computed tomography (CT) imaging in patients with suspected acute appendicitis and to evaluate the impact of CT on negative appendectomy and perforation rates. In patients clinically diagnosed of acute appendicitis the reported overall negative appendectomy rate is about 15-20%; 10% in men and 25-45% in women of childbearing age. This is associated with a perforation rate of 21-23%. METHODS: This is a retrospective analysis of 146 consecutive patients presenting with clinical symptoms suspicious of appendicitis over a 2-yr period in whom CT examinations were performed before therapy was instituted. The overall negative appendectomy and perforation rates were calculated for the entire group, as well as for the 54 women aged 15-50 yr in the childbearing cohort. RESULTS: The negative appendectomy rate was 4% in 122 patients operated on and the perforation rate was 22%. Among 36 women 15-50 yr of age operated on, the negative appendectomy rate was 8.3% and the perforation rate was 19%. Surgery was avoided in 24 patients, 18 of whom were women of childbearing age. CONCLUSIONS: The judicious use of CT imaging in patients with equivocal clinical presentation suspected of having appendicitis led to a significant improvement in the preoperative diagnosis. It resulted in a substantial decrease in the negative appendectomy rate compared to previously published reports, without incurring an increase in the perforation rate.

Acute Disease↗

PubMed1999

Computed tomography image analyzer: segmentation applying active contour models--"snakes".

Many diagnostic and therapeutic procedures depend on medical images. In order to overcome imperfections of obtained images which are due to acquisition process and to obtain new information from available images, many techniques have been developed. In this study relatively new method of image segmentation, active contour model--"snakes" was applied in analyzing computed tomography (CT) images in patients with acute head trauma. Using this method, lesion to brain (LBR) and ventricle to brain ratio (VBR) were obtained accurately. Quantitative variable LBR, is significantly higher in patients with other pathologic CT findings and who do not survive during hospitalization. Thus, by applying segmentation "snakes" model it is possible to extract maximum information from available CT scans. These variables could be basis for medical decision making in patients with acute head trauma.

Artifacts↗

PubMedDate not supplied

Characterization of small nodules by automatic segmentation of X-ray computed tomography images.

OBJECTIVE: To characterize the ability of an automatic lung nodule segmentation algorithm to measure small nodule dimensions and growth rates. METHODS: A phantom of 20 sets of 6 balls each (11 different nylon balls and 9 acrylic balls) of 1 to 9.5 mm in diameter, in foam, was imaged using x-ray computed tomography with slice thicknesses of 5, 2.5, and 1.25 mm, pitches of 3 and 6, and standard and lung resolution. Measurements consisted of volume and maximum in-plane cross-sectional areas and their derived maximum and effective diameters. Growth rates were simulated using pairs of groups of balls. RESULTS: Volume measurements overestimate volume, more so for thicker slices. For the largest balls, the error is 60% for 5-mm slices and 20% for 1.25-mm slices. Effective diameter calculated from volume better approximates actual diameter. For area measurements, errors are 0% to 5% for the largest balls, and the effective and actual diameters are closely matched. CONCLUSIONS: Below 5 mm in diameter, changes in volume should reach 100% for reliable indication of growth. Above 6 mm, the threshold for detecting change is on the order of 25% growth. Even under ideal conditions, results indicate the need for caution when making a diagnosis of malignancy on the basis of volume change.

Algorithms↗

PubMed2005

Quantitative single-photon emission computed tomography imaging.

Over the past decade, quantitation of cardiac single-photon emission computed tomography (SPECT) data, once limited to perfusion assessment, has been extended to global and regional function assessment for both the left and the right ventricle, as well as to measurement of additional cardiac parameters of diagnostic and prognostic interest. A number of commercially available quantitative algorithms exist, based on different mathematic operators and with varying degrees of automation, that are capable of providing accurate and reproducible results. This article describes the many quantitative cardiac SPECT measurements available today, defining them in terms of validation, practical use, and limitations.

Algorithms↗

PubMed2000

Comparison of intravenous midazolam with pentobarbital for sedation for head computed tomography imaging.

OBJECTIVE: To compare the efficacy of intravenous (IV) midazolam with that of IV pentobarbital when used for sedation for head computed tomography (CT) imaging in emergency department (ED) pediatric patients. METHODS: Prospective, randomized clinical trial in an urban children's hospital. During a two-and-a-half-year period, 55 patients were enrolled: 34 males and 21 females. Measurements included induction time, recovery time, efficacy, side effects, complications, and failure with each drug. Success of sedation was graded as good (GS), adequate (AS), poor (PS), or unsuccessful (US). RESULTS: Sedation for CT was used for patients with the following problems: head trauma (21/55), central nervous system pathology (17/55), ventriculoperitoneal shunt evaluation (6/55), periorbital cellulitis (6/55), and retropharyngeal abscess (5/55). Twenty-nine (53%) patients received pentobarbital (mean +/- SD dose 3.75 +/- 1. 10 mg/kg) and 26 (47%) patients received midazolam (mean +/- SD dose 0.2 +/- 0.03 mg/kg). In the pentobarbital group, 28 (97%) patients were scanned and successfully sedated. Pentobarbital's mean induction time was 6 minutes and duration of sedation averaged 86 minutes. In the midazolam group, only five (19%) patients were successfully scanned with midazolam alone. Of the 21 (81%) patients given midazolam who were unsuccessfully sedated, 12 (61%) were subsequently sedated with the addition of pentobarbital for completion of CT imaging. Mild oxygen desaturation, O(2) sat >90% yet <94%, was seen in only four patients. All four patients responded to blow-by oxygen and required no other intervention. CONCLUSION: Intravenous pentobarbital is more effective than IV midazolam for sedation of children requiring CT imaging.

Chi-Square Distribution↗

PubMed2001

Three-dimensional virtual computed tomography imaging for injured anterior cruciate ligament.

Three-dimensional virtual imaging using reconstructed volume data from helical computed tomography was applied to examine injured anterior cruciate ligaments (ACL) as a noninvasive diagnostic aid. Its diagnostic value for ACL injury was evaluated in 21 patients. These results were compared with those of arthroscopic findings. This new technique allowed visualization of the ACL in a three-dimensional form, similar to an arthroscopic image, and was 100% accurate in detecting ACL injuries in the present samples.

Adolescent↗

PubMed2006

Prostate contouring uncertainty in megavoltage computed tomography images acquired with a helical tomotherapy unit during image-guided radiation therapy.

PURPOSE: To evaluate the image-guidance capabilities of megavoltage computed tomography (MVCT), this article compares the interobserver and intraobserver contouring uncertainty in kilovoltage computed tomography (KVCT) used for radiotherapy planning with MVCT acquired with helical tomotherapy. METHODS AND MATERIALS: Five prostate-cancer patients were evaluated. Each patient underwent a KVCT and an MVCT study, a total of 10 CT studies. For interobserver variability analysis, four radiation oncologists, one physicist, and two radiation therapists (seven observers in total) contoured the prostate and seminal vesicles (SV) in the 10 studies. The intraobserver variability was assessed by asking all observers to repeat the contouring of 1 patient's KVCT and MVCT studies. Quantitative analysis of contour variations was performed by use of volumes and radial distances. RESULTS: The interobserver and intraobserver contouring uncertainty was larger in MVCT compared with KVCT. Observers consistently segmented larger volumes on MVCT where the ratio of average prostate and SV volumes was 1.1 and 1.2, respectively. On average (interobserver and intraobserver), the local delineation variability, in terms of standard deviations [Deltasigma = radical(sigma2MVCT-sigma2KVCT)], increased by 0.32 cm from KVCT to MVCT. CONCLUSIONS: Although MVCT was inferior to KVCT for prostate delineation, the application of MVCT in prostate radiotherapy remains useful.

Humans↗

PubMed2000

Knowledge-based segmentation of thoracic computed tomography images for assessment of split lung function.

The assessment of differential left and right lung function is important for patients under consideration for lung resection procedures such as single lung transplantation. We developed an automated, knowledge-based segmentation algorithm for purposes of deriving functional information from dynamic computed tomography (CT) image data. Median lung attenuation (HU) and area measurements were automatically calculated for each lung from thoracic CT images acquired during a forced expiratory maneuver as indicators of the amount and rate of airflow. The accuracy of these derived measures from fully automated segmentation was validated against those from segmentation using manual editing by an expert observer. A total of 1313 axial images were analyzed from 49 patients. The images were segmented using our knowledge-based system that identifies the chest wall, mediastinum, trachea, large airways and lung parenchyma on CT images. The key components of the system are an anatomical model, an inference engine and image processing routines, and segmentation involves matching objects extracted from the image to anatomical objects described in the model. The segmentation results from all images were inspected by the expert observer. Manual editing was required to correct 183 (13.94%) of the images, and the sensitivity, specificity, and accuracy of the knowledge-based segmentation were greater than 98.55% in classifying pixels as lung or nonlung. There was no significant difference between median lung attenuation or area values from automated and edited segmentations (p > 0.70). Using the knowledge-based segmentation method we can automatically derive indirect quantitative measures of single lung function that cannot be obtained using conventional pulmonary function tests.

Algorithms↗

PubMed2004

Neoplastic invasion of laryngeal cartilage: the significance of cartilage sclerosis on computed tomography images.

Cartilage sclerosis has been cited as a sensitive and a specific sign of neoplastic cartilage invasion, on cross-sectional computed tomography (CT) images of the larynx. We retrospectively reviewed 36 consecutive patients, who underwent a total laryngectomy for squamous cell carcinoma of the larynx. Preoperative CT images were compared with formal histological sections of the larynx in order to assess cartilage invasion by tumour. Isolated asymmetrical cartilage sclerosis was found to have a sensitivity of 62% and a specificity of 42% for predicting neoplastic cartilage invasion when compared with histopathological sections of the tumour. In this study we found that cartilage sclerosis was not a useful early radiological sign of neoplastic cartilage invasion when taken in isolation.

Arytenoid Cartilage↗

PubMed2006

Micro-focus X-ray computed tomography images of the 3D structure of the cranium of a fetus with asymmetric double malformation.

Reconstructed micro computed tomography (Micro-CT, micro-CT) images have revealed the detailed three-dimensional structure of the cranium of human fetal congenital anomalies for the first time. The objects were a head and a cervix of female autosite and a parasite consisting of only a head conjoined to the scapular region of the autosite of an asymmetric double malformation (asymmetric conjoined twins, heteropagus twinning) at a gestational age of 8 months. The cranium of the autosite was normal, but that of the parasite was characterized by otocephaly (agnathia, synotia, and monorhina) and almost all the cranial bones were of an abnormal shape. It is suggested that a part of occipital bone (the basioccipital and exoccipital bones), the vomer and cribriform plate were absent and this resulted in the fusion and overlapping of bilateral temporal and craniofacial bones that should have been adjacent to them. This resulted in a reformation and relocation of most of the cranial bones. Micro-CT is a useful tool to visualize the detailed bone structure which has not been clarified by the conventional dissection methods and other imaging technologies and is a powerful instrument for studying congenital anomalies.

Bone and Bones↗

PubMed2004

Ictal single-photon emission computed tomography imaging in extra temporal lobe epilepsy using statistical parametric mapping.

PURPOSE: To examine the application of statistical parametric mapping (SPM) to analyze ictal single-photon emission computed tomography (SPECT) scans in surgical candidates with extratemporal lobe epilepsy. METHODS: The authors selected patients who underwent successful ictal SPECT acquisition in the process of surgical treatment of intractable partial epilepsy. Thirteen patients were identified who met inclusion criteria for confident seizure localization from either intracranial electroencephalogram recordings or epilepsy surgery outcome. In these cases, ictal scans were registered to an in-house-developed normal SPECT atlas composed of 14 spatially normalized brains of normal subjects. SPM96 was used to test on a voxel-by-voxel basis for statistically significant increases in blood flow associated with each patient's ictal scan. The results were then mapped back onto the patient's magnetic resonance image (MRI) for final interpretation. Statistical parametric mapping (SPM) analysis of ictal SPECT scans was compared to both conventional visual interpretation and the analysis of subtraction ictal SPECT co-registered to MRI (SISCOM). RESULTS: Ten of 13 patient scans showed localizing focal ictal increases in regional cerebral blood flow, all of which were concordant with ultimate epilepsy localization. Of the 3 cases not localized with SPM, 1 was localized by conventional visual interpretation and another, not localized by visual interpretation, was correctly localized with SISCOM. Two cases not localized by SISCOM were localized by both visual and SPM analysis. CONCLUSIONS: This work provides supportive evidence for proof of principle that SPM can be used to provide objective, accurate analysis of ictal SPECT scans in patients with extratemporal lobe epilepsy.

Adolescent↗

PubMed2005

Usefulness of the 3-dimensionally reconstructed computed tomography imaging for diagnosis of the site of tracheal injury (3D-tracheography).

Computed tomography (CT) has not been considered useful for early diagnosis of traumatized patients who could hardly hold their breath, particularly patients with tracheal injuries. However, the recent development of spiral CT has made it possible to acquire contiguous patient data, which eliminates the respiratory misregistration. Air is easily differentiated from surrounding tissues by striking contrast, and the trachea can therefore be well displayed by three-dimensional (3D)-CT. We consider that it is possible to show tracheal injury by 3D-CT. The aim of this study is to clarify the usefulness of 3D-CT for detecting the injury site of blunt tracheal injuries. The study was carried out in hemodynamically stable patients who were suspected of having tracheal injury based on clinical manifestations such as hemoptysis, or cervical subcutaneous, deep cervical, or mediastinal emphysema. Repeated bronchoscopy confirmed tracheal injury. The virtual images of the 3D-CT (3D-tracheography) were compared with the direct images of bronchoscopic findings. Five cases were examined. In patients with tracheal injury, bronchoscopy revealed laceration of the tracheal lumen or disruption and dislocation of the tracheal cartilage, partially coated by mucus and clot, findings that confirmed the diagnosis of tracheal injury. The virtual images of the 3D-tracheography clearly showed the injury as a defect in the tracheal wall or a depression in the wall. The site and size of injury shown in the 3D-tracheography were comparable with those detected by bronchoscopy. We succeeded in detecting tracheal injuries by 3D-CT imaging, the virtual images of which were comparable with the bronchoscopic findings. 3D-tracheography is a useful method for diagnosing the site and form of tracheal injury in hemodynamically stable patients.

Adult↗

PubMed2005

Identifying high-risk asymptomatic diabetic patients who are candidates for screening stress single-photon emission computed tomography imaging.

OBJECTIVES: The purpose of this study was to identify which asymptomatic diabetic patients are candidates for screening single-photon emission computed tomography (SPECT) imaging and to examine angiographic findings and mortality in patients according to SPECT imaging categories. BACKGROUND: Previously we reported a high percentage of abnormal and high-risk SPECT imaging scans in asymptomatic diabetic patients. METHODS: We examined the associations between several clinical and laboratory variables and a high-risk stress SPECT imaging scan in 1,427 asymptomatic diabetic patients without known coronary artery disease (CAD). Results of coronary angiography and long-term outcome were also analyzed. RESULTS: An abnormal stress SPECT imaging scan was present in 826 patients (58%) and a high-risk scan in 261 patients (18%). Multivariate analysis demonstrated that seven variables were independently associated with a high-risk scan (model chi-square=107, p <0.0001). The two most important variables were electrocardiogram (ECG) Q waves (adjusted chi-square=38.3, p <0.001) and peripheral arterial disease (PAD) (adjusted chi-square=13.9, p <0.001). Coronary angiography was performed in 127 (49%) high-risk SPECT imaging patients, 61% of whom had angiographic high-risk CAD. Annual mortality rates for patient subsets categorized by SPECT imaging scans were high-risk 5.9%, intermediate-risk 5.0%, and low-risk 3.6% (p <0.001 for differences between groups). CONCLUSIONS: High-risk findings on stress SPECT imaging were present in 18% of asymptomatic diabetic patients without known CAD. Patients with high-risk scans had a high prevalence of severe CAD and a high annual mortality rate. ECG Q waves and/or evidence of PAD identified the most suitable candidates for screening.

Coronary Angiography↗