Computed Tomography Scout View Research Articles

Supplementary value and diagnostic performance of computed tomography scout view in the detection of thoracolumbar spine injuries.

Assessing the diagnostic performance and supplementary value of whole-body computed tomography scout view (SV) images in the detection of thoracolumbar spine injuries in early resuscitation phase and identifying frequent image quality confounders. In this retrospective database analysis at a tertiary emergency center, three blinded senior experts independently assessed SV to detect thoracolumbar spine injuries. The findings were categorized according to the AO Spine classification system. Confounders impacting SV image quality were identified. The suspected injury level and severity, along with the confidence level, were indicated. Diagnostic performance was estimated using the caret package in R programming language. We assessed images of 199patients, encompassing 1592 vertebrae (T10-L5), and identified 56 spinal injuries (3.5%). Among the 199 cases, 39 (19.6%) exhibited at least one injury in the thoracolumbar spine, with 12 (6.0%) of them displaying multiple spinal injuries. The pooled sensitivity, specificity, and accuracy were 47%, 99%, and 97%, respectively. All experts correctly identified the most severe injury of AO type C. The most common image confounders were medical equipment (44.6%), hand position (37.6%), and bowel gas (37.5%). SV examination holds potential as a valuable supplementary tool for thoracolumbar spinal injury detection when CT reconstructions are not yet available. Our data show high specificity and accuracy but moderate sensitivity. While not sufficient for standalone screening, reviewing SV images expedites spinal screening in mass casualty incidents. Addressing modifiable factors like medical equipment or hand positioning can enhance SV image quality and assessment.

The CT scout view: complementary value added to abdominal CT interpretation.

Computed tomography (CT) scout images, also known as CT localizer radiographs, topograms, or scanograms, are an important, albeit often overlooked part of the CT examination. Scout images may contain important findings outside of the scanned field of view on CT examinations of the abdomen and pelvis, such as unsuspected lung cancer at the lung bases. Alternatively, scout images can provide complementary information to findings within the scanned field of view, such as characterization of retained surgical foreign bodies. Assessment of scout images adds value and provides a complementary "opportunistic" review for interpretation of abdominopelvic CT examinations. Scout image review is a useful modern application of conventional abdominal radiograph interpretation that can help establish a diagnosis or narrow a differential diagnosis. This review discusses the primary purpose and intent of the CT scout images, addresses standard of care and bias related to scout image review, and presents a general systematic approach to assessing scout images with multiple illustrative examples, including potential pitfalls in interpreting scout images.

A simple method for the automatic classification of body parts and detection of implanted metal using postmortem computed tomography scout view.

Information on medical devices embedded in the body is important in the identification of an unidentified body. Computed tomography (CT) is a powerful imaging modality; however, metallic artifacts deteriorate the image quality because of the reconstruction method. On the contrary, CT scout view is less affected by metallic artifacts compared to CT. It is a simple method to classify the body into three rough parts for postmortem CT (PMCT) scout view, and an algorithm used to detect the location of the implanted metal has been developed for personal identification in forensic pathology. Of the test images, 97% were correctly classified into the three body parts. The true-positive rate for detection of the implanted metal in the scout view was 96.5%. Therefore, our simple methods are applicable in PMCT scout views and would be particularly useful for forensic pathology.

Comparison of Radiation Dose and Image Quality with Various Computed-Tomography Scout Views: The Angular Modulation Technique Based on Information Calculated from Scout Views

Background: While using the automatic exposure control technique in computed tomography (CT), the scout view determines the radiation dose for the CT scan by taking anatomical morphology into consideration. Objectives: The goal of this study was to estimate radiation doses during scout scanning and to evaluate the hypothesis that the radiation dose during CT depends on the location and order of the X-ray tubes. Materials and Methods: A CT scanner (GE VCT 64-channel) with the X-ray tubes placed in the anteroposterior (AP), lateral, and posteroanterior (PA) positions was used to acquire the scout views. The effective doses were assessed using an anthropomorphic chest phantom (RSD Inc., Long Beach, CA), an AAPM CT performance phantom (CIRS model 610), and CT dose indices (CTDI) head phantom. Both single and two scout views were tested with the three views combined according to the order of scanning. The CTDIs obtained from the CT unit dose report were used to compare the chest CT radiation doses, while the image quality was evaluated based on the root-mean-square error values calculated using the Image program. Results: The results of this study indicate that single AP (0°) scout views obtained with the z-axis modulation technique (AutomA) during chest CT scanning resulted in CTDIs that were lower than those generated by using lateral (90°) or PA (180°) scout views. The analysis of two-scout views using AutomA alone revealed the lowest CTDI in the 90° - 0° scout views. However, based on the CT image noise analysis, a scout angle order of 0°-90° resulted in the optimal scout view combination with the minimal dose. Conclusion: Scout views may be useful in determining dose and image quality in CT scanning; however, it is necessary to first determine the most appropriate scout view for CT scans.

Spectrum of Signs of Pneumoperitoneum

Pneumoperitoneum is caused by rupture of a hollow viscus that includes the stomach, small bowel, and large bowel, with the exception of those portions that are retroperitoneal in the duodenum and colon. The causes of pneumoperitoneum are numerous, ranging from iatrogenic and benign causes to more life-threatening conditions. In the absence of a benign cause of pneumoperitoneum, the identification of free intraperitoneal gas usually indicates the need for emergency surgery to repair a perforated bowel. The plain film is the primary diagnostic tool for detecting pneumoperitoneum: multiple signs of free intraperitoneal air can be found especially on supine abdominal radiographs. Computed tomography (CT) examination has been shown to be more sensitive than abdominal radiographs for the detection of free intraperitoneal air. It is important that the radiologist become familiar with the signs of pneumoperitoneum that can be discerned on abdominal radiographs, on CT scout view, and on CT scan.

Dislodgement of a Power-Injectable Peripherally Inserted Central Catheter After Power Injection: A Case Report

A 63-year-old Malay woman had a 6-French dual-lumen power-injectable peripherally inserted central catheter (PICC) inserted and subsequently underwent a contrast-enhanced computed tomography scan with intravenous contrast medium administered via the PICC. After the scan, the tip of the PICC was noted to have displaced from its original position and lodged in 1 of the small branches of the right subclavian vein. This phenomenon was then demonstrated in real time under fluoroscopy during the process of repositioning the PICC tip. Although power-injectable PICCs are designed for use with power injectors, tip displacement can and does happen. A computed tomography scout view of the chest may be necessary after each use of power injectors to confirm that the PICC tip remains in a satisfactory position.

A comparative study of linear measurements of facial skeleton using computed tomography and traditional cephalometry

Background: Radiographic imaging is an important adjunct in the assessment of skeletal and dental relationships for the orthodontic patient. Imaging is one of the most ubiquitous tools used by orthodontists to measure and record the size and form of craniofacial structures. Materials and Methods: The objectives of the study were to compare the measurements from human skulls and their images from cephalometric radiographs and computed tomography (CT) scanograms in order to gauge the potential use of CT in routine clinical practice. Based on the specific criteria including stable occlusion and condyles fitting stably in glenoid fossa, 15 dry human skulls were selected. Lateral, posteroanterior cephalograms, and CT scout views were taken of each skull by standardized methods. Linear measurements were made on all three records. Intraclass correlation coefficients, Pearson's correlation coefficient and regression constant were calculated to assess the records. Results: The linear measurements of the cephalometric record are greater than CT measurements on scout images. In vertical plane, the CT projections are more coinciding with the direct skull measurements. In sagittal and transverse planes, the cephalometric measurements were more correlating with the direct skull measurements. Conclusions: The cephalograms and CT scanograms differed in accuracy of linear measurements, because of variation in the location and size of an object, within the imaged 3D structure of both records.

Computed tomography scout views vs. conventional radiography in body-packers – Delineation of body-packs and radiation dose in a porcine model

ObjectiveTo compare abdominal computed tomography (CT) scout views with conventional radiography regarding radiation dose and delineation of drug packages in a porcine body-packer model. Materials and methodsNine samples of illicit drugs packed in ovoid plastic containers were consecutively placed in the rectum of a 121.5kg pig cadaver. Antero-posterior and lateral scout views were obtained at 120kVp and 80mA, 150mA and 200mA, respectively, using a 64-row MDCT. Scout views were compared with conventional abdominal antero-posterior radiographs (77kV and 106±13mAs). Visibility of three body pack characteristics (wrapping, content, shape) was rated independently by two radiologists and summarized to a delineation score ranging from 0 to 9 with a score ≥6 representing sufficient delineation. Mean delineation scores were calculated for each conventional radiography and single plane scout view separately and for a combined rating of antero-posterior and lateral scout views. ResultsEven the lowest single plane scout view delineation score (5.3±2.0 for 80mA lateral; 0.4mSv; sensitivity=44%) was significantly higher than for conventional radiographs (3.1±2.5, p<0.001; 2.4±0.3mSv; sensitivity=11%). Combined reading of antero-posterior and lateral scout views 80mA yielded sufficient delineation (6.2±1.4; 0.8mSv; sensitivity=56%). ConclusionsAll CT scout views showed significantly better delineation ratings and sensitivity than conventional radiographs. Scout views in two planes at 80mA provided a sufficient level of delineation and a sensitivity five times higher than conventional radiography at less than one third of the radiation dose. In case of diagnostic insecurity, CT can be performed without additional logistical effort.

Reliability of vertebral fracture assessment using multidetector CT lateral scout views: the Framingham Osteoporosis Study

Two radiologists evaluated images of the spine from computed tomography (CT) scans on two occasions to diagnose vertebral fracture in 100 individuals. Agreement was fair to good for mild fractures, and agreement was good to excellent for more severe fractures. CT scout views are useful to assess vertebral fracture. We investigated inter-reader agreement between two radiologists and intra-reader agreement between duplicate readings for each radiologist, in assessment of vertebral fracture using a semi-quantitative method from lateral scout views obtained by CT. Participants included 50 women and 50 men (age 50-87 years, mean 70 years) in the Framingham Study. T4-L4 vertebrae were assessed independently by two radiologists on two occasions using a semi-quantitative scale as normal, mild, moderate, or severe fracture. Vertebra-specific prevalence of grade ≥ 1 (mild) fracture ranged from 3% to 5%. We found fair (κ = 56-59%) inter-reader agreement for grade ≥ 1 vertebral fractures and good (κ = 68-72%) inter-reader agreement for grade ≥ 2 fractures. Intra-reader agreement for grade ≥ 1 vertebral fracture was fair (κ = 55%) for one reader and excellent for another reader (κ = 77%), whereas intra-reader agreement for grade ≥ 2 vertebral fracture was excellent for both readers (κ = 76% and 98%). Thoracic vertebrae were more difficult to evaluate than the lumbar region, and agreement was lowest (inter-reader κ = 43%) for fracture at the upper (T4-T9) thoracic levels and highest (inter-reader κ = 76-78%) for the lumbar spine (L1-L4). Based on a semi-quantitative method to classify vertebral fractures using CT scout views, agreement within and between readers was fair to good, with the greatest source of variation occurring for fractures of mild severity and for the upper thoracic region. Agreement was good to excellent for fractures of at least moderate severity. Lateral CT scout views can be useful in clinical research settings to assess vertebral fracture.

CT scout view as an essential part of CT reading

Computed tomography scout view is a mode of operating a CT system. It is generally used to prescribe CT slices and to display slice locations rather than for direct diagnosis. However, we found that a careful study of CT scout view can contribute significantly to the diagnosis. We show seven abdominal, two chest and two head CT, where the study of CT scout view allowed diagnoses to be made that were not readily apparent from the axial slices.

Intrinsic measurement bias on computed tomography scout view is unpredictable: Computed tomography pelvimetry using a phantom

Our aim was to determine the degree of bias in CT scanogram measurements. We obtained standard lateral and anteroposterior (AP) pelvimetry scanograms of a phantom pelvis after placing ball bearings or aluminium rods to mark bony landmarks. Computed tomography pelvimetry was carried out at the manufacturer-recommended table height on two commercial CT scanners and at 10-mm increments up to 50 mm above and below this height. The AP inlet, AP outlet, interspinous distance and transverse diameters were each measured three times for each scanogram. The true measurements were obtained directly from the disassembled phantom. Bias was defined as the difference between the CT measurement and the true measurement. Observer error was negligible. The transverse diameter was overestimated at high table positions and underestimated at low table positions on both scanners (+6 to -10 mm). After correcting for geometric distortion, up to 6 mm bias was still present. The point at which no bias occurred was different for each scanner and did not correspond to the manufacturers' recommended table height. The outlet was overestimated on both scanners by up to 5 mm. The true inlet measurement was overestimated by 1.2 mm. The interspinous distance was minimally underestimated on both scanners. The measurements on CT scanogram were underestimated or overestimated in an inconsistent and unpredictable fashion, varying from one type of measurement to another and from CT scanner to CT scanner. This has implications for the accuracy and clinical utility of measurements obtained from a CT scanogram.

Limitations of Radiography and Computed Tomography in the Diagnosis of Transverse Sacral Fracture From a High Fall

Transverse sacral fractures with sacral canal compression and neurologic deficit are rare sequelae of high falls. Nevertheless, a high index of suspicion is necessary as such an injury may present significant complications and may be missed on standard anteroposterior pelvic roentgenograms and pelvic computed tomography (CT) examinations obtained during the evaluation of multiple traumas. The saddle anesthesia, loss of bladder and sphincter function, and sexual dysfunction may be masked or unrecognized during the acute phase of polytrauma. Special attention must be directed to obtaining a lateral profile view of the sacrum, as this deformity may not be seen in any other view. Sagittal reconstruction images of the sacrum can be obtained during a pelvic CT examination if the initial lateral roentgenograms are technically inadequate because of the patient's obesity or limitations of portable radiographic equipment in the emergency department. The CT scoutview itself may show the acute sacral angulation if sufficient technique factors are employed. The roentgenographic suspicions can be confirmed with lateral multidirectional tomography or even with sagittal magnetic resonance imaging (MRI). Because this transverse sacral fracture is unstable in flexion, additional neurologic injury may result if the spine or hips are unwittingly manipulated in flexion.

Artifacts seen during CT pelvimetry: implications for digital systems with scanning beams.

During computed tomography (CT) pelvimetry of two pregnant women, bony abnormalities of the fetuses were noted on the scout images that were not confirmed at delivery. To explore the cause of these artifacts, specimen long bones were manipulated in various ways during CT scout imaging. Artifacts like those seen during in vivo imaging were found to be caused by motion of the object. The CT scout view is an example of an image produced by a digital system that uses a scanning beam. This type of digital system is being used for several types of body imaging including screening for scoliosis and chest radiography. Attention to motion artifacts should decrease diagnostic errors and aid further development of these systems.