Scout View Research Articles

Lower limb alignment in the frontal plane: analysis from long standing radiographs and computer tomography scout views: an experimental study

A profound knowledge of physiologic lower limb alignment is essential to understand deformities and to plan surgical correction. The gold standard in radiographic assessment is the long standing radiograph with a forward directed patella. The advantage of computed tomography (CT) is that its cutting-edge image technique can visualize the femur condyles. Study purpose was to determine if the CT-scout view has the potential to replace the standing radiograph. We compared the geometric data obtained from long standing radiograph and CT-scout views both with patella forward position. Furthermore, we developed a method of positioning the lower extremity stable on the CT table, where the femoral condyles became the new orientation criterion. Finally, we evaluated differences in the data ascertainment between the long standing radiograph with patella facing forward and the CT-scout view with the posterior edge of femoral condyles orientated parallel to the radiographic cassette. The geometric data of long standing radiograph and CT-scout views are comparable if the leg is in the same rotational position. We developed a CT positioning jig to adjust the femur condyles parallel to the radiographic cassette. In 80 % of the cases, the deviation was 5° or less. These scout views showed statistically significant differences when compared with data from standing radiograph with a forward centered patella. No evidence was found clearly excluding the possibility of an exclusive use of the CT-scout view for the analysis of the leg geometry. However, advantages of the long standing radiograph became obvious.

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.

Scout View X-Ray Attenuation Versus Weight-Based Selection of Reduced Peak Tube Voltage in Cardiac CT Angiography

The study evaluated the relationship between cardiac computed tomography (CT) scout view x-ray attenuation and CT image noise compared with weight or body mass index (BMI). Decreasing peak tube voltage from 120 to 100 kVp on the basis of body size reduces radiation exposure. Methods to better predict CT image noise may lead to more effective selection of reduced tube voltage in cardiac CT. Image quality was graded subjectively (1 [excellent] to 4 [nondiagnostic]) and objectively (SD of the aortic attenuation value) in cardiac CT angiograms (N = 106) acquired at either 100 or 120 kVp. X-ray attenuation characteristics on the scout view (120 kVp, 30 mA) were measured within a 3-cm region of interest across the chest in the frontal x-ray. Receiver-operating characteristic curve analysis was performed comparing scout view attenuation versus weight and BMI in predicting CT image noise and quality. CT image noise correlated with both BMI (r = 0.40; p < 0.001) and the scout view attenuation value (r = 0.52; p < 0.001). In linear regression models with controlling for BMI (or weight) and tube potential, scout view attenuation was the best predictor of the CT image noise (p < 0.001), and increased model fit statistic from 0.23 to 0.41 (p model <0.001). At 120 kVp, scout view attenuation predicted CT image noise <30 Hounsfield units (HU) more accurately than BMI (area under the curve: 0.89 vs. 0.77). For CT images acquired at 120 kVp, those with a scout view attenuation <-120 HU had significantly lower noise and higher signal-to-noise ratios, with similar mean aortic attenuation values. A majority (89.3%) of "low-noise" CT images at 120 kVp had scout view attenuation values of <-120 HU. Scout view attenuation predicts cardiac CT image noise better than weight or BMI and could enable broader application of reduced x-ray tube voltage as a radiation sparing technique.

Femoral head-neck offset in the Indian population: A CT based study

Background:Femoroacetabular impingement has been postulated as the important cause of primary osteoarthritis in non dysplastic hips. We postulated that the rarity of primary osteoarthritis of hip in Indian population could be attributable to morphological differences, specifically to a lower prevalence of abnormal head–neck morphology. We conducted an anthropometric study to evaluate the prevalence of abnormal head–neck offset in Indian population and to correlate it with the low prevalence of primary osteoarthrosis in the Indian population.Materials and Methods:The computed tomography (CT) images of 85 apparently normal hips were analysed. An axial image was created parallel to the central axis of the femoral neck and passing through the center of the femoral head using coronal scout view. This image was then used to calculate alpha and beta angles and the head–neck offset ratio. The measurements were made by two independent observers on two different occasions.Results:The prevalence of abnormal head–neck offset ratio was 11.7% and the mean alpha and beta angles were 45.6° and 40.6°, respectively. Pearson correlation coefficients for intra-observer and inter-observer agreement were, respectively, 0.84 and 0.80 for alpha angle, 0.80 and 0.77 for beta angle and 0.78 and 0.75 for head–neck offset ratio. The values were similar to those reported in the western population.Conclusion:The differences in the prevalence of hip osteoarthritis in Indian and western populations are not attributable to variation in the prevalence of abnormal head–neck offset.

Abstract 2571: Quantitative Analysis of Cobalt Alloy Clip Artifacts in 64 channel Three Dimensional CT Angiography and Introducing Strategies for Minimizing Metallic Artifacts

Objective Clip artifacts on postoperative CT scans after aneurysmal clipping, can create confusion, especially in cases of cobalt alloy clips. Mathematic analysis of the parameters influencing the degree of clip artifact in 64-channel 3 dimensional CT angiography (3D CTA) was conducted to develop methods for minimizing metallic artifacts. Materials and Methods CT images from 60 cases with single straight Sugita cobalt alloy clips (Mizuho Ikakogyo Co., Tokyo) were analyzed. The degree of the angle between the imaging acquisition gantry angle and clip blade on the CT axial scan (x, y) and on the lateral scout view (z) was measured as independent variables. The length of the clip blade was also measured. Analysis of whether the spring of the clip was included in the 5mm thick scan slide was performed. The dependent variables were the maximal diameter of the white artifact, degree of the symmetrical angle of the streak artifact and the maximal diameter of clip artifact in 3D volume rendering. Univariate and multivariate analysis was conducted to elucidate relationship between each parameters and each type of clip artifacts. Results The degree of the angle between z axis and clip blade was negatively correlated with the amount of white artifact (p&lt;0.0001, R=-0.589) and positively with the streak artifact (angle of the streak artifact: p&lt;0.0001, R=0.636; number of the streak artifact: p&lt;0.0001, R=0.505). When the spring of the clip was included parallel in scan section, the amount of white artifact was increased (p&lt;0.0001). On multiple linear regression analysis, angle of clip blade to z axis was the major parameter influencing all kinds of artifacts (white artifact: p&lt;0.005, angle of the streak artifact: p&lt;0.0001, number of the streak artifact: p&lt;0.0001). Conclusions Metallic artifact was increased when the degree of angle between the clip blade and z axis became near to zero. Clip artifacts after aneurysmal clipping could be minimized with simple maneuvers such as minimal changes of the scan gantry angle on the lateral scout view if the clip blade was parallel to the gantry angle or the clip spring portion was included in the scan cross section.

CT in children – dose protection and general considerations when planning a CT in a child

Today CT represents about 10% of all ionizing radiation based imaging modalities, but delivers more than 50% of the total collective dose for diagnostic imaging. Compared to adults the radiation sensitivity of children is considerable higher than in adults. Additionally children differ from adults – factors like body size, mass, density, proportions as well as metabolism have to be mentioned. Children grow and maturate – all this components have to be mapped in examination protocols by Pediatric Radiology. The total dose of a CT examination depends on the settings of several factors such as the scout view, the scan length, exposure settings including automated exposure control, type of scanning (single slice, helical, volume mode), slice thickness, pitch values as well as on image reconstruction parameters. If intravenous contrast media injection is needed bolus tracking or timing represents another source of radiation.The aim of the paper is to present and discuss all aspects of defining a pediatric age and query adapted CT protocol particularly concerning all dose relevant factors in pediatric CT and their adjustment in children. Moreover hints are given concerning optimization of intravenous contrast media injection as well as special (low dose) imaging protocols.

Power Injectable Peripherally Inserted Central Venous Catheter Lines Frequently Flip After Power Injection of Contrast

To determine the frequency of power injectable peripherally inserted central venous catheter (PIPICC) displacement after contrast injection for computed tomography. We included all patients who had a computed tomographic examination with contrast administration via PIPICC over a 4-month period. Several variables including catheter location before and after the injection were documented. Descriptive statistics were used for continuous variables. The χ² test was used to compare groups. Continuous variables were analyzed using the Student t test. Among 78 injections in 67 patients (34 men and 33 women; median age, 49 years), there were 12 catheter displacements (15.4%): 5 (62.5%) of 8 catheters initially located proximal to the tracheobronquial angle (TBA) and 7 (10.14%) of 69 catheters initially located distal to the TBA. The initial catheter position before the injection correlated with the frequency of displacement significantly (P < 0.006). Contrast injection rate and amount of contrast were no risk factors for position change. There were no complications. Catheter displacement occurred in 62.5%, with PIPICCS cephalad to the TBA. A preliminary scout view should be checked before the contrast injection. In addition, a postinjection scan scout view is recommended to verify catheter position.

Heritability of prevalent vertebral fracture and volumetric bone mineral density and geometry at the lumbar spine in three generations of the framingham study

Genetic factors likely contribute to the risk for vertebral fractures; however, there are few studies on the genetic contributions to vertebral fracture (VFrx), vertebral volumetric bone mineral density (vBMD), and geometry. Also, the heritability (h(2)) for VFrx and its genetic correlation with phenotypes contributing to VFrx risk have not been established. This study aims to estimate the h(2) of vertebral fracture, vBMD, and cross-sectional area (CSA) derived from quantitative computed tomography (QCT) scans and to estimate the extent to which they share common genetic association in adults of European ancestry from three generations of Framingham Heart Study (FHS) families. Members of the FHS families were assessed for VFrx by lateral radiographs or QCT lateral scout views at 13 vertebral levels (T(4) to L(4)) using Genant's semiquantitative (SQ) scale (grades 0 to 3). Vertebral fracture was defined as having at least 25% reduction in height of any vertebra. We also analyzed QCT scans at the L(3) level for integral (In.BMD) and trabecular (Tb.BMD) vBMD and CSA. Heritability estimates were calculated, and bivariate genetic correlation analysis was performed, adjusting for various covariates. For VFrx, we analyzed 4099 individuals (148 VFrx cases) including 2082 women and 2017 men from three generations. Estimates of crude and multivariable-adjusted h(2) were 0.43 to 0.69 (p < 1.1 × 10(-2)). A total of 3333 individuals including 1737 men and 1596 women from two generations had VFrx status and QCT-derived vBMD and CSA information. Estimates of crude and multivariable-adjusted h(2) for vBMD and CSA ranged from 0.27 to 0.51. In a bivariate analysis, there was a moderate genetic correlation between VFrx and multivariable-adjusted In.BMD (-0.22) and Tb.BMD (-0.29). Our study suggests vertebral fracture, vertebral vBMD, and CSA in adults of European ancestry are heritable, underscoring the importance of further work to identify the specific variants underlying genetic susceptibility to vertebral fracture, bone density, and geometry.

The prevalence of cam-type femoroacetabular deformity in asymptomatic adults

We performed a retrospective examination of the anteroposterior pelvic CT scout views of 419 randomly selected patients between April 2004 and August 2009 in order to determine the prevalence of cam-type femoroacetabular deformity in the asymptomatic population. The CT scans had all been undertaken for conditions unrelated to disorders of the hip. The frequency of cam-type femoroacetabular deformity was assessed by measuring the α-angle of each hip on the anteroposterior images. The α-angles were classified according to the Copenhagen Osteoarthritis Study. Among 215male hips (108patients) the mean α-angle was 59.12° (37.75° to 103.50°). Of these, a total of 30 hips (13.95%) were defined as pathological, 32 (14.88%) as borderline and 153 (71.16%) as normal. Among 540female hips (272 patients) the mean α-angle was 45.47° (34.75° to 87.00°), with 30 hips (5.56%) defined as pathological, 33 (6.11%) as borderline and 477(88.33%) as normal. It appears that the cam-type femoroacetabular deformity is not rare among the asymptomatic population. These anatomical abnormalities, as determined by an increased α-angle, appear to be twice as frequent in men as in women. Although an association between osteoarthritis and femoroacetabular impingement is believed to exist, a long-term epidemiological study is needed to determine the natural history of these anatomical abnormalities.

Identification of prevalent vertebral fractures using CT lateral scout views: a comparison of semi-automated quantitative vertebral morphometry and radiologist semi-quantitative grading

We compared vertebral fracture assessment by semi-automated quantitative vertebral morphometry measurements with the conventional semi-quantitative (SQ) grading using lateral CT scout views. The semi-automated morphometry method showed good to excellent agreement with the visual SQ grading by radiologists for identification of vertebral fractures. Semi-automated quantitative vertebral morphometry (QM) measurements may enhance management of osteoporosis patients by providing an efficient means to identify vertebral fractures (VFx). We compared identification of prevalent VFx by semi-automated QM to SQ grading. A non-radiologist performed semi-automated QM from CT lateral scout views in 200 subjects (102 men, 98 women, 65.8 ± 8.9 years) selected from the Framingham Heart Study Multidetector CT Study. VFx were classified in the QM approach based on using Genant's criteria for deformities, and compared with conventional SQ grading performed by experienced radiologists as the gold standard. The kappa (k) statistics, percent agreement (% Agree), sensitivity (SE), specificity (SP), positive predictive value (PPV), and negative predictive value (NPV) were computed. Among 200 subjects, 57 had mild and 41 had moderate or severe VFx by visual SQ grading. Per-person analyses showed excellent agreement between the two methods, with k = 0.780. The % Agree ranged from 86.7% to 91.2%, the SE was 81.3%-96%, and the SP was 86.5%-92%. Among 2,588 vertebrae analyzed, 107 had mild and 49 had moderate or severe VFx by visual SQ grading. Per-vertebra analyses revealed good agreement, with k = 0.580. Agreement between the methods tended to be highest in L1-L4 region. Agreement and validity measures were higher when only moderate and severe fractures were included. The semi-automated quantitative vertebral morphometry measurements from CT lateral scout views provided good to excellent agreement with the standard SQ grading for assessment of prevalent vertebral fractures.

SU‐E‐T‐254: Comprehensive Quality Assurance Program for Accelerated Partial Breast Irradiation Using the SAVI HDR Applicator

Purpose: To present a comprehensive prescriptive quality assurance (QA) program for Accelerated Partial Breast Irradiation (APBI) using the Cianna Medical SAVI (Strut Adjusted Volume Implant) multi‐catheter applicator. Methods: We established a robust QA program for the SAVI technique based on our previous experience with various HDR procedures and documentation provided by the manufacturer. During the simulation, the location of the SAVI in relation to the patientˈs anatomy is recorded by measuring the distance from the patientˈs skin to the SAVIˈs hub, by marking the skin and denoting which catheter aligned with the mark, and by taking AP and lateral scout views. A “SAVI Simulation Worksheet” was developed to denote the key measurements during the simulation QA. Our QA process continues with treatment planning. After the plan is reviewed by the physician, the physicist checks the delineation of each catheter and the dose distributions using a developed “Pre‐Plan Check Sheet” as a guide. The third set of the major checks is performed prior to each delivery. The SAVI location is verified via repeating the measurements taken during the simulation including the daily images. A therapist and physician sign‐off are required. “HDR Treatment Check” is the last key component of the QA flow, which required 3 independent checks of the catheter connections, dwell positions and time, and post‐treatment checks. Results: 10 SAVI patients have been treated using the QA protocol. There was 1 catheter each for 2 patients that were misconnected. This error was detected by the third independent checker. Conclusions: We established a robust QA program for the SAVI technique and successfully implemented it for 10 SAVI patients, 100 treatments. We are initiating Failure Modes and Effects Analysis (FMEA) for the SAVI process to better distribute the limited resources and enhance the efficiency and safety of our SAVI program.

Measurement of leg length discrepancy after total hip arthroplasty. The reliability of a plain radiographic method compared to CT-scanogram

To measure the interobserver reliability and intraobserver reproducibility of post total hip arthroplasty (THA) leg length discrepancy (LLD) measurement on radiographs as well as to evaluate its accuracy by comparing it with LLD measurement on computed tomographic scanogram (CT-scanogram). In this prospective study, postoperative LLD measurements in ten THA patients were made by four observers on anteroposterior radiographs of the pelvis (inter-teardrop line to the tip of lesser trochanter) and compared to LLD measurements made on CT-scanogram scout views of the lower limb. Two observers repeated the LLD measurements on radiographs 8weeks after the first measurements. The interobserver reliability of the LLD measurement on plain radiographs was evaluated by comparing the measurements of the four observers and the intraobserver reproducibility by comparing the two repeated measurements made by the two observers. We found excellent interobserver reliability (mean ICC 0.83) and intraobserver reproducibility (ICC 0.90 and 0.88) of the LLD measurements on plain radiographs. There was a moderate to excellent agreement, but with wide variation of measurements among the four observers, when plain radiographic measurement was compared with CT-scanogram (ICC 0.58, 0.60, 0.71, and 0.82). Despite the excellent interobserver reliability and intraobserver reproducibility of LLD measurement on radiographs, clinicians should be aware of its limited accuracy when compared to CT-scanogram.

Acetabular Morphology in Slipped Capital Femoral Epiphysis

Children with unilateral slipped capital femoral epiphysis (SCFE) often appear to have overcoverage of their contralateral (normal) side. This increased coverage can be a contributing factor to femoroacetabular impingement. The purpose of this study was to quantify the coverage of the normal hip in patients with unilateral SCFE and to compare our results to matched controls. Between 2003 and 2008, we identified 50 patients treated for unilateral, stable SCFE by in-situ screw fixation. Using postoperative anteroposterior and frog radiographs of the pelvis, the lateral center-edge angle (LCEA) and Tönnis angle (TA) were measured on the uninvolved side. Pelvic tilt was evaluated to ensure the quality of the radiographs, and in those patients with appropriate films, the presence or absence of a posterior wall sign and cross-over sign was noted. Results were compared with 50 age and sex-matched controls. Control data was generated from scout views of otherwise healthy patients who underwent an abdominal computed tomography scan to rule out acute appendicitis. The mean LCEA and TA of the contralateral acetabulum were 33 and 5 degrees, respectively (range: 18 to 47; -7 to 13). Seventy-eight percent had a positive cross-over sign and 39% had a posterior wall sign. In comparison, the mean LCEA and TA in our control group were 20 and 8 degrees, respectively (range: 8 to 35; -6 to 23). In this group, 21% had a positive cross-over sign whereas 15% had a positive posterior wall sign. We found a significantly higher LCEA and lower TA in the study population compared with controls (P=1.6E-16, 0.0003), as well as a higher prevalence of retroversion signs (P=5E-7, 0.02). The contralateral acetabulum in patients with treated unilateral SCFE demonstrates significantly more coverage compared with matched controls. In addition, there is a significantly higher prevalence of acetabular retroversion in these patients. Our findings should alert caregivers to the potential of developing femoroacetabular impingement on the contralateral side in patients who have had a unilateral SCFE. III (retrospective case-control).

Renal fornix rupture following diagnostic coronarography

A 31-year-old man with an uneventful medical history presented at the emergency department with complaints of exercise-related chest pain for 3 weeks. ECG showed ST-elevations in the inferior leads. A diagnostic coronarography was performed and showed multivessel coronary stenosis. During this procedure 200 ml of a nonionic, low-osmolality monomeric contrast agent (Iomeron 350®) and 1250 ml of isotonic saline solution was administered intravenously. After this procedure, the patient suffered from a sudden onset and progressive severe pain in the back and the right lumbar region. A plain CT of the abdomen performed 8 hours post coronarography showed contrast enhanced fluid in the renal sinus and the perinephric/peri-ureteral space (Fig. A (scout view), B (coronal) and C (sagittal) reformatted scans). There was a bladder overdistenstion with a CT-based volumetric estimation of 995 ml. No mechanical cause of upper urinary tract obstruction was present. Subsequent urological work-up included insertion of a bladder catheter (24 hours) and administration of peroral antibiotics. Ultrasound follow-up on the next day revealed no abnormalities and the patient was discharged.

Intra-and inter-reader reliability of semi-automated quantitative morphometry measurements and vertebral fracture assessment using lateral scout views from computed tomography

Intra-and inter-reader reliability of semi-automated quantitative vertebral morphometry measurements was determined using lateral computed tomography (CT) scout views. The method requires less time than conventional morphometry. Reliability was excellent for vertebral height measurements, good for height ratios, and comparable to semi-quantitative grading by radiologists for identification of vertebral fractures. Underdiagnosis and undertreatment of vertebral fracture (VFx) is a well-known problem worldwide. Thus, new methods are needed to facilitate identification of VFx. This study aimed to determine intra- and inter-reader reliability of semi-automated quantitative vertebral morphometry based on shape-based statistical modeling (SpineAnalyzer, Optasia Medical, Cheadle, UK). Two non-radiologists independently assessed vertebral morphometry from CT lateral scout views at two time points in 96 subjects (50 men, 46 women, 70.3 ± 8.9years) selected from the Framingham Heart Study Offspring and Third Generation Multi-Detector CT Study. VFxs were classified based solely on morphometry measurements using Genant's criteria. Intraclass correlation coefficients (ICCs), root mean squared coefficient of variation (RMS CV) and kappa (k) statistics were used to assess reliability. We analyzed 1,246 vertebrae in 96 subjects. The analysis time averaged 5.4 ± 1.7min per subject (range, 3.2-9.1min). Intra-and inter-reader ICCs for vertebral heights were excellent (>0.95) for all vertebral levels combined. Intra-and inter-reader RMS CV for height measurements ranged from 2.5% to 3.9% and 3.3% to 4.4%, respectively. Reliability of vertebral height ratios was good to fair. Based on morphometry measurements alone, readers A and B identified 51-52 and 46-59 subjects with at least one prevalent VFx, respectively, and there was a good intra-and inter-reader agreement (k = 0.59-0.69) for VFx identification. Semi-automated quantitative vertebral morphometry measurements from CT lateral scout views are convenient and reproducible, and may facilitate assessment of VFx.

Low-dose computed tomography to detect body-packing in an animal model

Objective To assess the possible extent of dose reduction for low-dose computed tomography (CT) in the detection of body-packing (ingested drug packets) as an alternative to plain radiographs in an animal model. Materials and methods Twelve packets containing cocaine (purity >80%) were introduced into the intestine of an experimental animal (crossbred pig), which was then repeatedly examined by abdominal CT with stepwise dose reduction (tube voltage, 80 kV; tube current, 10–350 mA). Three blinded readers independently evaluated the CT datasets starting with the lowest tube current and noted the numbers of packets detected at the different tube currents used. In addition, 1 experienced reader determined the number of packets detectable on plain abdominal radiographs and ultrasound. Results The threshold for correct identification of all 12 drug packets was 100 mA for reader 1 and 125 mA for readers 2 and 3. Above these thresholds all 3 readers consistently identified all 12 packets. The effective dose of a low-dose CT scan with 125 mA (including scout view) was 1.0 mSv, which was below that of 2 conventional abdominal radiographs (1.2 mSv). The reader interpreting the conventional radiographs identified a total of 9 drug packets and detected 8 packets by abdominal ultrasound. Conclusions Extensive dose reduction makes low-dose CT a valuable alternative imaging modality for the examination of suspected body-packers and might replace conventional abdominal radiographs as the first-line imaging modality.

Less Invasive Surgical Correction of Adult Degenerative Scoliosis, Part I

Adult scoliosis is a condition with increasing prevalence and medical and socioeconomic importance. Surgery is fraught with a significant complication rate in an elderly multimorbid patient population. To assess technical feasibility and radiographic results of image-guided less invasive correction of adult degenerative scoliosis. Thirty individuals (age, 64-88 years) with progressive deformity (coronal Cobb angles > 25 degrees and < 85 degrees), intractable back pain, radiculopathy, or neurogenic claudication were treated by less invasive decompression and fusion (unilateral transforaminal interbody cage instrumentation and bilateral facet fusions) with recombinant human bone morphogenetic protein-2, spanning 3 to 8 segments (average, 6 segments), using biplanar fluoroscopy or intraoperative computed tomography (iCT)-based navigation. Accuracy of screw placement, curve correction, and fusion rate were evaluated during a mean follow-up of 19.6 months. With 415 screws implanted, misplacement (grade II or greater) was not observed, and no implants required revision. Spinal iCT with automated registration required 17.5 +/- 8.5 minutes (single registration for all segments); monosegmental bilateral screw insertion required 6.8 +/- 3.4 minutes. Mean sagittal (coronal) Cobb angle correction was 44.8 +/- 10.7 degrees (31.7 +/- 13.7 degrees). Mean lumbar lordosis increased from 8.8 +/- 8.9 degrees to -36 +/- 6.9 degrees, and sagittal balance was reduced from 31.6 +/- 15.2 to 8 +/- 8.4 mm. Solid fusion was confirmed in 90% of instrumented segments at 16 months. Average radiation dose to the surgeon was 0.025 mSv for single-level transforaminal lumbar interbody fusion with fluoroscopic guidance vs 0 mSv with iCT navigation. Instrumented correction of adult deformity was significantly facilitated by iCT navigation, eliminating radiation exposure to the surgeon. Intraoperative biplanar CT scout views including pelvis and shoulders allow comprehensive assessment of multiplanar deformity correction. Fusion rates obtained with less invasive access equal those of conventional open technique.

SU-GG-I-56: Testes and Uterine Dose Measurements from Scout View in Lumbar Puncture Procedure and Regular Pelvic CT Scan

Purpose: The purpose of this study was to measure the dose to testes and uterus from the scout views of lumbar puncture procedure and during a routine pelvic CT scan.Materials and methods: Five high sensitivity MOSFETs (TN‐1002RD, Best Medical, Canada) were placed in the testes (2 dosimeters), uterus (2 dosimeters) and skin (1 dosimeter in lower abdomen area) of an adult anthropomorphic phantom (Model 701‐D, CIRS, Norfolk, VA). A 16‐detector array Lightspeed GECT scanner (GE Healthcare, Milwaukee, WI) was used. The phantom was placed in a prone position during the scout views for the lumbar puncture protocol. The scan parameters for anteroposterior (AP) scout were 120 kVp and 10 mA, and for the lateral (LAT) 120 kVp and 80 mA. The doses of the AP and LAT scout views were combined. During the regular pelvic CT scan the phantom was placed in supine position and scanned helically in automatic tube current modulation at 120 kVp and 440 mA (max tube current), the noise index was 11.57 and the CTDIvol was 14.44 mGy. The phantom was scanned three times and the average dose was obtained for each location. Results: The AP and LAT doses to the testes, uterus and skin during the scout views were measured to be 0.02±0.0005,−0.04±0.002 and 0.02±0.007 cGy, respectively. The dose to the testes, uterus and skin during the routine pelvic CT scan was 1.8±0.33, 1.6±0.08, and 2.4±0.50 cGy, respectively. Conclusion: The testes and uterine dose was assessed for the scout view of lumbar puncture procedure. The dose to testes and uterus was on the order of 200–400 microGy, which is, on average, 2% of the pelvic CT scan dose. We conclude that the scout view dose to the testes and uterus is negligible.

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.

Individualized tube current selection for 64-row cardiac CTA based on analysis of the scout view

Purpose To obtain consistent CCTA image quality and patient dose optimization with an individualized tube current selection method based on analysis of CT scout scans. Methods and materials The study received a waiver of informed consent from the institutional review board. Initially 100 patients (Group A) underwent CCTA with a fixed mA. The scout view pixel value and CCTA image noise were measured. Their correlation was studied to establish a formula to determine the required mA for obtaining a CT exam with a specific image noise. One hundred patients (Group B) were then scanned with the formula-determined mA. CCTA image quality, image noise and effective dose from the two groups were statistically analyzed. CT findings for 32 Group B patients were compared with the conventional coronary angiography. Results An average CCTA image noise of 27.6 HU was obtained (target 27 HU) using the formula with more uniform image noise in Group B (standard deviation 2.4 HU) than in Group A (4.1 HU). There was no statistical difference between image quality scores for the two groups. The effective dose for Group B (7.8 mSv) was 30% lower than for Group A (11.2 mSv) ( p < 0.01). CCTA sensitivity, specificity, positive predictive value, negative predictive value, and stenosis detection accuracy were 94.9%, 92.1%, 88.9%, 96.5% and 93.2%, respectively, for stenosis greater than 50%. Conclusion CCTA mA selection based upon the image characteristics of the CT scout view provides an individualized protocol that generates consistent image quality and helps to reduce overall patient dose.