Transverse Computed Tomography Research Articles

Cross-sectional anatomy, computed tomography, and magnetic resonance imaging of the banded houndshark (Triakis scyllium)

Due to their important phylogenetic position among extant vertebrates, sharks are an invaluable group in evolutionary developmental biology studies. A thorough understanding of shark anatomy is essential to facilitate these studies and documentation of this iconic taxon. With the increasing availability of cross-sectional imaging techniques, the complicated anatomy of both cartilaginous and soft tissues can be analyzed non-invasively, quickly, and accurately. The aim of this study is to provide a detailed anatomical description of the normal banded houndshark (Triakis scyllium) using computed tomography (CT) and magnetic resonance imaging (MRI) along with cryosection images. Three banded houndsharks were scanned using a 64-detector row spiral CT scanner and a 3 T MRI scanner. All images were digitally stored and assessed using open-source Digital Imaging and Communications in Medicine viewer software in the transverse, sagittal, and dorsal dimensions. The banded houndshark cadavers were then cryosectioned at approximately 1-cm intervals. Corresponding transverse cryosection images were chosen to identify the best anatomical correlations for transverse CT and MRI images. The resulting images provided excellent detail of the major anatomical structures of the banded houndshark. The illustrations in the present study could be considered as a useful reference for interpretation of normal and pathological imaging studies of sharks.

Evaluation of hip joint laxity in crab-eating foxes (Cerdocyon thous)

ABSTRACT: Like canids, crab-eating foxes may probably be predisposed to similar orthopedic diseases of domestic dogs, such as hip dysplasia. However, for the adequate hip dysplasia diagnosis in wild animals, the normality characteristics of each species must be determined. This study aimed to estimate radiographic and computed tomographic (CT) values of hip joint laxity in healthy crab-eating foxes. Fifteen intact crab-eating foxes, eight males and seven females, ages 1 to 5 and mean body mass of 6.66kg were used. Norberg angle (NA) was calculated from ventrodorsal hip-extended radiographs. To calculate the dorsolateral subluxation (DLS) score, the center distance (CD) index, the lateral center edge angle (LCEA), and the dorsal acetabular rim angle (DARA), measurements obtained from transverse CT images were used. No statistically significant differences were observed between the right and left sides in the radiographic and tomographic parameters. The mean NA was 107.57°. The mean DLS score, the CD index, the LCEA, and the DARA were 60.79%, 0.16, 98.25° and 13.47°, respectively. The data obtained are helpful in characterizing mean values of the hip joint in healthy crab-eating foxes, and can contribute to the knowledge of the species.

The accuracy of a novel pedicle screw insertion technique assisted by a special angular scale in the subaxial cervical spine using lateral mass as a reference marker

BackgroundPosterior cervical pedicle screw (CPS) internal fixation has better biomechanical stability than other posterior cervical fixation methods. However, this technique is limited in clinical practice due to the complex anatomical structure and the adjacent relationship of the cervical pedicle, and the high risk of neurovascular injury. The purpose of this study was to describe a novel subaxial CPS insertion technique assisted by a special angular scale using lateral mass as a reference marker and to evaluate the accuracy of CPS placement and the distribution characteristics of CPS misplacement.MethodsA total of 36 patients with subaxial cervical spine diseases who underwent posterior CPS fixation were consecutively selected. The optimal entry point on the posterior surface of the lateral mass was identified on the three-dimensional cervical model reconstructed from preoperative computed tomography (CT) images. The pedicle transverse angle (PTA) and pedicle-lateral mass angle (PLMA) were measured on the transverse and sagittal CT images respectively. The pedicle screws were inserted according to the preoperatively planned entry point and angles. We analysed the postoperative CT images for CPS misplacement rates and perforation directions following the Lee classification.ResultsOverall, 177 pedicle screws were inserted, of which 119 (67.2%) were classified as grade 0, 43 (24.3%) as grade 1, 12 (6.8%) as grade 2 and 3 (1.7%) as grade 3 by the postoperative CT images. The accuracy rate of CPS placement was 91.5%. Of the 15 misplaced pedicle screws (grades 2 and 3), 11 were lateral pedicle perforations, 3 were superior perforations and 1 was an inferior perforation. There were no neurovascular injuries related to CPS misplacement.ConclusionsWith our technique, the optimal entry point and two angles (PTA and PLMA) were identified for CPS insertion. The novel CPS insertion technique assisted by a special angular scale provides high accuracy and few complications.

Combined computed tomography and position-resolved X-ray diffraction of an intact Roman-era Egyptian portrait mummy.

Hawara Portrait Mummy 4, a Roman-era Egyptian portrait mummy, was studied with computed tomography (CT) and with CT-guided synchrotron X-ray diffraction mapping. These are the first X-ray diffraction results obtained non-invasively from objects within a mummy. The CT data showed human remains of a 5-year-old child, consistent with the female (but not the age) depicted on the portrait. Physical trauma was not evident in the skeleton. Diffraction at two different mummy-to-detector separations allowed volumetric mapping of features including wires and inclusions within the wrappings and the skull and femora. The largest uncertainty in origin determination was approximately 1.5 mm along the X-ray beam direction, and diffraction- and CT-determined positions matched. Diffraction showed that the wires were a modern dual-phase steel and showed that the 7 × 5 × 3 mm inclusion ventral of the abdomen was calcite. Tracing the 00.2 and 00.4 carbonated apatite (bone's crystalline phase) reflections back to their origins produced cross-sectional maps of the skull and of femora; these maps agreed with transverse CT slices within approximately 1 mm. Coupling CT and position-resolved X-ray diffraction, therefore, offers considerable promise for non-invasive studies of mummies.

Anatomy of the Tarsometatarsal Region and Digits in the Ostrich (Struthio Camelus): A Computed Tomography and Cross-Sectional Study.

The ostrich is the largest living bird and has unique characteristics in its locomotor system that differentiate it from other bird species. The purpose of this study was to provide a reference atlas of reference-interval computed tomography (CT) and cross-sectional anatomy of the tarsometatarsal region and digits in the ostrich (Struthio camelus). The pelvic limbs of 25 ostriches were used for this imaging study. The transverse CT images were obtained from the middle third of the tarsometatarsal bone to the distal end of the third digit. The specimens were frozen and sectioned with an electric band saw at 1.5-2 cm intervals. The CT images were compared with the corresponding frozen cross sections. The bones, ligaments, and tendons were identified and labeled at each 1.5-2 cm intervals. The CT images provided anatomic details of the tendons and ligaments in the tarsometatarsal region and digits of the ostrich. The transverse CT images provided an excellent depiction of the anatomic structures of the leg and foot when compared with the corresponding frozen cross sections. The information presented in this study may be used as an initial reference when evaluating the CT images of an ostrich's tarsometatarsal region and digits. Moreover, the information provided in this report may be helpful in determining definitive diagnoses of musculoskeletal disorders affecting the lower leg in this species.

Cystatin C and Sarcopenia Predict Acute on Chronic Liver Failure Development and Mortality in Patients on the Liver Transplant Waiting List.

Cystatin C (CysC) is an early biomarker of renal dysfunction scarcely studied in patients awaiting liver transplantation (LT). Sarcopenia is frequent in cirrhosis and impacts prognosis. We aimed to assess the capability of these factors to predict survival and acute-on-chronic liver failure (ACLF) in patients awaiting LT, as well as early post-LT outcomes. Single-center study that included all cirrhotic patients listed for LT between 2014 and 2017. Competing risk regression analysis was used to evaluate the capability of liver-, kidney-, and global status-related variables at waitlist (WL) inclusion to predict WL mortality and ACLF. Variables associated with post-LT outcomes were evaluated with logistic regression analysis. One-hundred-and-eighty patients were included. Fifty-six (31%) patients developed ACLF, 54 (30%) underwent LT and 35 (19%) died. In the adjusted competing risk regression analysis, CysC ≥ 1.5 mg/L, sarcopenia and MELD-Na were independent predictors of ACLF in the WL, while CysC ≥ 1.5 mg/L, sarcopenia and albumin were independent predictors of mortality. The cumulative incidence of ACLF and mortality at 12 months were 50% and 34% in patients with sarcopenia and CysC ≥1.5 mg/L. An estimated glomerular filtration rate by chronic kidney disease (CKD)-EPI-CysC-creatinine <60 mL/min/1.73 m at WL inclusion was an independent predictor of the need for renal replacement therapy (RRT) in the first month post-LT. Higher levels of CysC and sarcopenia are strongly associated with the ACLF and mortality in WL. The assessment of both risk factors may improve the prognostic evaluation and allow identifying a group of patients with a very high risk of poor outcomes while awaiting LT.

Whirlpool sign of adnexal torsion on CT: where can we find it?

Background Whirlpool sign on computed tomography (CT) is pathognomic of adnexal torsion. Purpose To evaluate the visibility and common location of the whirlpool sign in adnexal torsion on CT. Material and Methods This retrospective study included 143 consecutive patients who underwent preoperative CT imaging and subsequent surgically confirmed as adnexal torsion. Two readers independently recorded the presence and location of whirlpool sign in adnexal torsion on CT. Patients with and without whirlpool sign were compared with regard to the size of the adnexal mass and the degree of torsion. Results Whirlpool sign was detected in 60 (42.0%) patients on the transverse CT plane and 79 (55.2%) patients on the coronal CT plane of 143 patients. The sign was significantly better detected on the coronal CT plane than on the transverse CT plane ( P = 0.03). The most common location of the sign included the posterolateral aspect of the adnexal mass on the transverse CT plane (25/60, 41.7%, P = 0.04) and the upper-lateral aspect of the adnexal mass on the coronal CT plane (45/79, 60.0%, P &lt; 0.001). The size of the adnexal mass with whirlpool sign was significantly larger than the mass without whirlpool sign on the transverse CT plane (median 9.6 vs. 8.6 cm, P = 0.03). No significant difference in the degree of torsion was found between patients with and without whirlpool sign on CT ( P = 0.56–0.62). Conclusion Whirlpool sign of adnexal torsion is well detected at the upper-lateral aspect of adnexal mass on the coronal CT plane.

Sacroiliac joint morphologic changes from infancy to adulthood

BACKGROUND CONTEXTReport of sacroiliac morphology changes during growth is limited in the literature and the interest of such morphology and its consequence for surgery is increasing. PURPOSEAims of this work are (1) to anatomically define the sacroiliac joint (SIJ), and (2) to assess the influence of growth on the sacroiliac morphology and the pelvic parameters. STUDY DESIGNForty-nine young subjects from 6 months to 18 years old (y/o) and 20 adults aged from 18 to 50 y/o were selected from our institutional patient database. METHODSThey underwent a computed tomography (CT) examination on a 128-MDCT (GE Healthcare Optima CT660). Transverse CT image datasets were reconstructed, anonymized, and segmented with ITK-SNAP. Landmarks and surfaces were selected and a SIJ orientation analysis was performed using costumed Python scripts. RESULTSThe subjects were divided into four groups: infants (1.9±1 y/o), children (6.9±1.7 y/o), adolescents (13.7±1.8 y/o), and adults (27.3±5.6 y/o). Differences between SIJ orientation were found significant between young subject groups for synovial sacrum SIJ orientation (p<.001) and iliac total SIJ orientation (p=.036). Both orientations of younger subjects were found significantly different from the adult group (p<.035). SIJ synovial sacrum and iliac total orientations correlated significantly with age (p<.03). All orientations correlated with pelvic incidence (p<.04) except for synovial sacrum SIJ orientation (p=.2). No gender or symmetrical differences were found significant in any group. CONCLUSIONSMorphologic definition of the SIJ confirmed the independency of the gender during growth. Such results will be beneficial for the analysis and management of vertebral pathology.

Renal Artery Diameter Is a Surrogate Marker for Kidney Volume in Living Kidney Donors

Donor kidney volume (KV) is an increasingly important parameter evaluated before living kidney donation; however, KV measurements on computed tomographic (CT) scanning requires a manually intensive process of manual or semiautomatic segmentation of kidneys with interobserver variation. Renal artery diameter (RAD) is an easier marker to measure, and this study aims to investigate the relationship between donor RAD and KV. MethodsA retrospective review of 77 patients who underwent living donor nephrectomy was conducted. Bilateral KVs were measured based on contrast-enhanced CT scan imaging, and renal artery maximum diameter was measured by direct visualization on the arterial phase of transverse CT sections. ResultsOn regression analysis, there was a significant association between the right and left RADs and their ipsilateral KVs with a regression coefficient of 7.9 (95% CI, 1.3–14.5; P = .02) and 9.8 (95% CI, 3.3–16.3; P = .004), respectively. Mean total RAD correlated with total KV with a regression coefficient of 9.3 (95% CI, 3.8–14.7; P = .001) and weakly correlated with estimated glomerular filtration rate with a Pearson coefficient of .10. ConclusionsThis study demonstrates that renal artery size is positively associated with KV and may be used as an easily measured surrogate marker for kidney size with its attended implications in living donor transplantation.

Evaluation of interthalamic adhesion size as an indicator of brain atrophy in dogs with and without cognitive dysfunction.

Interthalamic adhesion thickness has been previously described as a parameter for quantifying canine brain atrophy and hypothesized to correlate with brain height or ventricular size. However, studies testing this hypothesis are lacking. This retrospective cross-sectional study aimed to compare interthalamic adhesion thickness, interthalamic adhesion thickness/brain height ratio, and interthalamic adhesion thickness/brain height ratio/lateral ventricle to brain height ratio values in dogs with and without cognitive dysfunction. Medical records for dogs meeting the following inclusion criteria were retrieved from two hospitals: available brain magnetic resonance imaging (MRI) or computed tomography (CT) studies, no cerebral parenchymal lesions, and no prior neurological treatment. For each included dog, values of interthalamic adhesion thickness, interthalamic adhesion thickness/brain height ratio, and interthalamic adhesion thickness/brain height ratio/lateral ventricle to brain height ratio were measured by one observer from transverse CT or MRI images and a consensus was reached. A total of 113 dogs met inclusion criteria. Dogs were divided into three groups based on the following criteria: Young group (no cognitive dysfunction, <9-year-old, n = 43), Aging group (no cognitive dysfunction, ≥9-year-old, n = 61), and Dementia group (n = 9). All three parameters were significantly lower in the dementia group than in the Young and Aging groups. In the Young and Aging groups, there was significant negative correlation of all three parameters with age and positive correlation of interthalamic adhesion thickness and interthalamic adhesion thickness/brain height ratio/lateral ventricle to brain height ratio with body weight, while there was no correlation of interthalamic adhesion thickness/brain height ratio with body weight (P < 0.05). There were no differences in all three parameters according to skull type or gender. Findings from the current study supported the use of interthalamic adhesion thickness, interthalamic adhesion thickness/brain height ratio, and interthalamic adhesion thickness/brain height ratio/lateral ventricle to brain height ratio for quantifying brain atrophy in dogs with cognitive dysfunction.

Diagnosing Sarcopenia on Thoracic Computed Tomography: Quantitative Assessment of Skeletal Muscle Mass in Patients Undergoing Transcatheter Aortic Valve Replacement

This study aims to assess the use of skeletal muscle mass measurements at two thoracic levels to diagnose sarcopenia on computed tomography (CT) chest examinations and to analyze the impact of these measurements on clinical outcome parameters following transcatheter aortic valve replacement. This study retrospectively included 157 patients who underwent preoperative CT examinations. The total muscle area was measured on transverse CT images at the 3rd lumbar and 7th and 12th thoracic levels with skeletal muscle indices (SMIs) calculated at each level. SMIs were then compared to clinical outcome parameters, and thoracic cutoff values for sarcopenia at the 7th and 12th thoracic levels were calculated. Correlation between SMIs at the third lumbar vertebra (L3) and the 12th thoracic vertebra (T12) was stronger (r = 0.724, P < 0.001) than that between L3 and the seventh thoracic vertebra (T7) (r = 0.594, P < 0.001). SMIs at L3 and T12 significantly correlated with prolonged length of stay. Thoracic cutoff values for the 12th thoracic level were 42.6 cm2/m2 (men) and 30.6 cm2/m2 (women), and those for the 7th thoracic level were 46.5 cm2/m2 (men) and 32.3 cm2/m2 (women). Skeletal muscle measurements at the T12 level could permit the diagnosis of sarcopenia and could be used to correlate sarcopenia with outcome parameters in patients undergoing CT limited to the chest.

Skeletal Muscle Abnormalities Increase the Risk of Overt Hepatic Encephalopathy and Hyperammonemia in Patients With Cirrhosis

Background and Aim: Skeletal muscle abnormalities, such as sarcopenia and myosteatosis are frequent complications of cirrhosis and are associated with increased morbidity and mortality. Hyperammonemia plays a significant role in the pathogenesis of hepatic encephalopathy (HE). Skeletal muscle have a significant compensatory part in detoxifying ammonia during liver disease since it houses the enzyme glutamine synthetase, an important ammonia-removing pathway during the amination of glutamate to glutamine. Therefore, we aimed to investigate whether reduced quantity and quality of muscle is associated with hyperammonemia, HE and mortality in patients with cirrhosis. Methods: A total of 677 cirrhotic patients were evaluated. Computed tomography (CT) scans were used to analyze the skeletal muscle (transverse CT image at the level of the 3rd. lumbar vertebra (L3) was selected from each scan) and sarcopenia and myosteatosis was evaluated. Overt HE was assessed clinically and ammonia blood levels were performed at the time of the muscularity assessment. Results: Sarcopenia was noted in 292 patients (43%), and 352 patients had myosteatosis (52%). A total of 225 patients (33%) had history of overt HE and 221 (of 267) patients (83%) had hyperammonemia. The prevalence of overt HE was higher in patients with sarcopenia (42% vs. 27%, P < 0.001), and myosteatosis (41% vs. 25%, P < 0.001). By multivariable regression analysis, sarcopenia and myosteatosis were independently associated with higher risk of overt HE (HR 1.89, P = 0.007, HR 1.68, P = 0.03) and hyperammonemia (HR 1.71, P = 0.006, HR 1.88, P = 0.001, respectively). Median survival was worse in patients with overt HE and sarcopenia (18 ± 4 vs. 42 ± 7 months, P = 0.01), hyperammonemia and sarcopenia (11 ± 7 vs. 38 ± 16 months, P < 0.001), and myosteatosis and hyperammonemia (19 ± 3 vs. 38 ± 20 months, P = 0.005) compared to patients without these factors. Conclusions: Cirrhotic patients with sarcopenia and myosteatosis have a higher risk of hyperammonemia and overt HE. Further, skeletal muscle abnormalities present concomitantly with HE and hyperammonemia increase the risk of mortality in these patients. The authors have none to declare.

Are Traditional Radiographic Methods Accurate Predictors of Pedicle Morphology?

Cadaveric in vitro computed tomography (CT) imaging study. To examine minimum pedicle diameter from transverse and coronal CT reconstructions of thoracolumbar spine specimens and compare their degree of disparity, if any. Pedicle angulation in coronal and transverse planes was measured and their contribution to the disparity in minimum pedicle diameter was assessed. Spinal minimum pedicle diameter can be obtained from both transverse and coronal CT reconstructions; however, the degree of disparity in these measurements has not been described previously. Angulation of the pedicle in transverse and coronal planes may contribute to a disparity in minimum pedicle diameter acquired from reconstructions. This also has not been described previously. This study examined whether the disparity could be predicted by spinal level, as pedicle angulations vary in both coronal and transverse planes. Five thoracolumbar specimens (T1-L5, age 48-59 yrs, male) were CT scanned utilizing clinical protocols. Minimum pedicle diameters and pedicle angulations were acquired in transverse and coronal reconstructions. Disparities between minimum pedicle diameters were measured and the correlation between this disparity and spinal level was characterized. A significant difference (P < 0.001) in minimum pedicle diameter existed between measures from coronal and transverse reconstructions. There was a significant correlation (P < 0.001) between the difference in minimal pedicle diameter and the transverse pedicle angle as well as the coronal pedicle angle. An overestimation of minimum pedicle diameter in the transverse reconstruction occurs when the coronal pedicle angulation increases, and in the coronal reconstruction when the transverse pedicle angulation increases. Therefore, pedicle angle should be determined using both coronal and transverse reconstructions and utilized to reduce the risk of overestimation of the true pedicle diameter. NA.

Feasibility for Measuring Transverse Area Ratios and Asymmetry of Lumbosacral Region Paraspinal Muscles in Working Dogs Using Computed Tomography.

Describe computed tomographic (CT) anatomy of canine lumbosacral (LS) paraspinal muscles, a method for measuring paraspinal muscle transverse area ratios and asymmetry using CT, and application of this method in a small sample of working dogs with versus without LS pain. Published anatomy references and atlases were reviewed and discrepancies were resolved by examination of anatomic specimens and multiplanar reformatted images to describe transverse CT anatomy of LS region paraspinal muscles. Sixteen Belgian malinois military working dogs were retrospectively recruited and assigned to LS pain positive versus negative groups based on medical record entries. A single observer unaware of dog group measured CT transverse areas of paraspinal muscles and adjacent vertebral bodies, in triplicate, for L5-S1 vertebral locations. A statistician compared muscle transverse area ratios and asymmetry at each vertebral location between groups. The relative coefficient of variation for triplicate CT area measurements averaged 2.15% (N = 16). Multifidus lumborum (L6-7), psoas/iliopsoas (L5-6, L6-7), and sacrocaudalis dorsalis lateralis (L6-7, L7-S1) transverse area ratios were significantly smaller in dogs with LS pain (n = 11) versus without LS pain (n = 5) (p ≤ 0.05). Muscle asymmetry values were not significantly greater in dogs with versus without LS pain. Computed tomographic morphometry of LS region paraspinal muscles is a feasible objective method for use in future evidence-based research studies in working dogs. Potential future research applications include determining whether decreased paraspinal muscle area ratios and/or increased paraspinal muscle asymmetry could be used as markers for preclinical LS pain in stoic dogs or risk factors for other injuries in high performance canine athletes, or determining whether core muscle strengthening exercise prescriptions for dogs with LS pain have an effect on paraspinal muscle area ratios and asymmetry.

Computed tomographic arthrography of the normal dromedary camel carpus.

The aim of this prospective cadaveric study was to provide a detailed computed tomographic (CT) reference of the carpal joint in healthy dromedary camels. Twelve forelimbs of six apparently healthy camels were used. Computed tomographic imaging of 12 normal cadaveric camel carpal joints was performed before and after intra-articular administration of iodinated contrast medium. Transverse CT images were reconstructed in dorsal and parasagittal planes. The six carpal bones, the radial trochlea, and the proximal articular surface of the metacarpal bones were clearly visible on CT images with the bone setting window. Radiocarpal, carpometacarpal, transverse intercarpal, medial and lateral palmer intercarpal, middle intercarpal, accessory carpoulnar and medial and lateral collateral ligaments, carpal canal, joint capsule, and the extensor and flexor tendons were identified on CT images with the soft-tissue setting window. Postcontrast CT images provided better delineation of intercarpal ligaments, the capsular compartments and recesses. Results indicated that the osseous and the clinically important soft tissue structures of the dromedary camel carpal joint could be identified using CT and CT arthrography. The CT data of this study will serve as a basis for diagnosis of carpal problems in camels.

Computed Tomographic Features of the Osseous External Ear Canal, Tympanic Membrane, and Tympanic Bulla in Clinically Normal Horses

Only sparse anatomic and morphometric information exists concerning the equine acoustic organ. The aim of the present study was, therefore, to describe the computed tomographic (CT) anatomy and determine the CT dimensions of the osseous external ear canal (OEEC), tympanic membrane (TM), and tympanic bulla (TB) in clinically normal horses. Computed tomography of the head was performed in 23 horses, presented for reasons unrelated to the auditory organ, with a 4-slice (group 1) or a 40-slice (group 2) CT scanner, respectively. The following measurements of the OEEC were performed: volume, dorsal, ventral and central length, halfway of central length, and inner diameter at four different locations. Length of the TM, width of the hypotympanon and the largest width and height of the external acoustic porus (EAP), and the TB were also recorded. The OEEC in all ears was of an oval, truncated cone shape running in a dorsolateral to medioventral direction. The TM coursed at a flat angle from dorsolateral to medioventral and had a wave-like appearance on transverse CT images. Significantly lower width and height of the EAP, inner diameter of the OECC at its narrowest point, and OEEC volume were found in group 1. A significant positive correlation between OEEC volume and head length or body weight, respectively, was found in group 2. Results of the present study may serve as reference values and aid the diagnosis of aural abnormalities and disease conditions. Moreover, they provide a basis for the adjustment of audiometric testing devices to horses.

Quantitative evaluation of cervical cord compression by computed tomographic myelography in Thoroughbred foals.

ABSTRACTFive Thoroughbred foals (age, 8–33 weeks; median age, 31 weeks; weight, 122–270 kg; median weight, 249 kg) exhibiting ataxia with suspected cervical myelopathy (n=4) and limb malformation (n=1) were subjected to computed tomographic (CT) myelography. The areas of the subarachnoid space and cervical cord were measured on transverse CT images. The area of the cervical cord was divided by the area of subarachnoid space, and stenosis ratios were quantitatively evaluated and compared on the basis of histopathological examination. The sites with a ratio above 52.8% could have been primary lesion sites in the histopathological examination, although one site with a ratio of 54.1% was not a primary lesion site. Therefore, in this study, a ratio between 52.8–54.1% was suggested to be borderline for physical compression that damages the cervical cord. All the cervical vertebrae could not be scanned in three of the five cases. Therefore, CT myelography is not a suitable method for locating the site of compression, but it should be used for quantitative evaluation of cervical stenosis diagnosed by conventional myelography. In conclusion, the stenosis ratios determined using CT myelography could be applicable for detecting primary lesion sites in the cervical cord.

Suspected Pulmonary Thromboembolism and Deep Venous Thrombosis: A Comprehensive 64-slice Multidetector Computed Tomography Diagnosis in Gynecologic Patients.

Suspected Pulmonary Thromboembolism and Deep Venous Thrombosis: A Comprehensive 64-slice Multidetector Computed Tomography Diagnosis in Gynecologic Patients.

Definition of a quantitative measurement method for acetabular version in a plain radiograph in the healthy adult hip.

This study aims to define a quantitative measurement method for acetabular version in a standard anteroposterior hip radiograph, assess the intraobserver and interobserver agreements of this method, and compare it with the gold standard computed tomography (CT). Anteroposterior standard hip radiographs and simultaneously taken transverse acetabular CT sections of 78 hips of 39 patients (10 males, 29 females; mean age 60 years; range 40 to 81 years) were used in the study. In standard anteroposterior hip radiographs, "acetabular anterior wall line" was identified as the line between the most lateral edge of the acetabulum and the inferolateral edge of the teardrop. "Acetabular posterior wall line" was identified as the line between the most lateral edge of the subchondral sclerosis and the outmost point of acetabulum posterior lunate surface sclerosis. To assess the reliability of this technique, mentioned angles in 78 hips were measured by two authors independently two weeks apart. Direct radiographic values were compared with the acetabular version measurement values in CT examination. Mean acetabular version angles of 78 hips in plain radiographs and CT were 18.0° (9-25°) and 17.2° (12-25°), respectively. Mean intraobserver measurement differences were 1.3° (0-5°) and 1.5° (0-6°). Mean interobserver measurement difference was 1.4° (0-5°). The mean difference between plain radiography measurements and CT measurements was 2.5° (0-6°). A significant correlation was detected between plain radiographic measurements and CT measurements. By this quantitative method, acetabular morphology may be measured less invasively, easily, quickly and reliably in plain radiograph in transverse plane.

Lung nodule and cancer detection in computed tomography screening.

Fundamental to the diagnosis of lung cancer in computed tomography (CT) scans is the detection and interpretation of lung nodules. As the capabilities of CT scanners have advanced, higher levels of spatial resolution reveal tinier lung abnormalities. Not all detected lung nodules should be reported; however, radiologists strive to detect all nodules that might have relevance to cancer diagnosis. Although medium to large lung nodules are detected consistently, interreader agreement and reader sensitivity for lung nodule detection diminish substantially as the nodule size falls below 8 to 10 mm. The difficulty in establishing an absolute reference standard presents a challenge to the reliability of studies performed to evaluate lung nodule detection. In the interest of improving detection performance, investigators are using eye tracking to analyze the effectiveness with which radiologists search CT scans relative to their ability to recognize nodules within their search path in order to determine whether strategies might exist to improve performance across readers. Beyond the viewing of transverse CT reconstructions, image processing techniques such as thin-slab maximum-intensity projections are used to substantially improve reader performance. Finally, the development of computer-aided detection has continued to evolve with the expectation that one day it will serve routinely as a tireless partner to the radiologist to enhance detection performance without significant prolongation of the interpretive process. This review provides an introduction to the current understanding of these varied issues as we enter the era of widespread lung cancer screening.