Helical CT Scans Research Articles

Epinephrine-enhanced computed tomographic arthrography of the canine shoulder

The aim of this study was to investigate the effect of epinephrine-enhanced computed tomographic arthrography (CTA) on the image sharpness of the lateral and medial glenohumeral ligaments (LGHL and MGHL, respectively), biceps tendon (BT) and joint cartilage (JC) in the canine shoulder.The shoulders of eight normal dogs were examined using a 4-slice helical CT scanner. The right shoulders were injected with Iohexol and the left shoulders with a mixture of Iohexol and epinephrine. CTA images were obtained after 1, 3, 5, 9, 13, 20 and 30min and the image sharpness of the intra-articular structures in both shoulders was graded for visibility. The attenuation values were measured to examine the persistence of contrast appearance. Admixture of epinephrine and Iohexol significantly improved the image sharpness of the LGHL and the BT, especially on delayed CTA images. The use of epinephrine did not negatively affect post-CTA recovery.

SU-F-207-11: On the Relationship of Minimum Required Dose to Low Contrast Detectability and Blending Fractions With Adaptive Statistical Iterative Reconstruction (ASIR) in Abdominal CT

Purpose: It is of practical use to obtain the dose for a specified low contrast lesion detectability and a given ASIR fraction before the scan. To achieve the goal, we investigated the relationship of the minimum required dose to low contrast detectability and ASIR blending fraction in abdominal CT scans. Methods: A realistically shaped abdomen phantom (CIRS TE-07) with an embedded vertebral bone rod was utilized. Helical CT scans were performed on a GE 750 HD at two dose levels of 8 mGy and 18 mGy. The images were reconstructed using different ASIR fractions (0–100%). The noise images, obtained using subtraction from adjacent slices, were partitioned into different scales using matrices of square cells sized differently. The noise at each cell size can be quantified by the standard deviation (sd) of the cell mean pixel values distribution. Upon verifying that the distributions follow Gaussian, we proposed that the statistically defined minimum detectable contrast (MDC) can be applied to ASIR reconstructed images, i.e., MDC = 3.29sd. We then defined the normalized MDC (N_MDC) as the ratio of the MDC with ASIR to the MDC with filtered backprojection and postulated that N_MDC is dose independent. N_MDC was obtained at each cell size from different ASIR blending fractions at different dose levels. Results: The matrix cell means distribution was verified following Gaussian. N_MDC was found to linearly decrease as the ASIR blending fraction increases. The relationship is the same with two distinct doses. For the specified MDC at lesion size d and ASIR blending fraction (s), the minimum required dose D = [14.05(1-bs)/(MDC*d^1.12)]^2.03, where b = 0.005/d^0.784. Conclusion: The relationship of the minimum required dose to low contrast detectability and ASIR blending fraction was obtained. It can be used to adjust the scan parameters corresponding to the calculated minimum required dose.

TH-CD-303-04: A Method for Assessing Ground-Truth Accuracy of a Motion Model Based 4DCT Technique

Purpose: To develop a technique that validates a breathing motion model and its reconstructed phase-specific image generation process using the original free-breathing images as ground truths. Methods: 16 lung cancer patients underwent the published protocol where 25 free-breathing fast helical CT scans were acquired with a simultaneous breathing surrogate. The first image was arbitrarily selected as the reference image. For constructing patient-specific lung motion model, state-of-the-art deformable image registration was employed to determine lung tissue displacement. The motion model was used, along with the free-breathing phase information of the original 25 image datasets, to generate a set of deformation vector fields (DVF) that mapped the reference image to the 24 non-reference images. The set of original images was simulated by applying the inverted model DVF to the reference image. To test the robustness of model simulation over the entire lung region, the model simulated image was deformably registered to the original scan. The resulting deformation vector magnitude evaluated the point-wise discordance in the lung region. Results: Qualitative comparison of image overlay showed excellent agreement between the simulated and the original images. The mean error across the patient cohort was 1.15±0.37 mm, while the mean 95th percentile error was 2.47±0.78 mm. Conclusion: Despite a large variety of breathing patterns and lung deformations, the proposed technique can accurately reproduce the original free-breathing helical CT scans, suggesting its applicability to a wide range of patients. The proposed ground truth based analysis is unique in CT-based breathing motion modeling for radiation therapy and will provide uncertainty estimations in the model-based 4DCT breathing motion estimate of tumors and normal organs. This work was supported in part by NIH R01 CA096679

SU‐E‐T‐383: Evaluation of Deep Inspiration Breath‐Hold Technique for Post‐Mastectomy Proton Pencil Beam Scanning Therapy

Purpose:Deep inspiration breath‐hold techniques (DIBH) have been shown to carry significant dosimetric advantages in conventional radiotherapy of left‐sided breast cancer. The purpose of this study is to evaluate the use of DIBH techniques for post‐mastectomy radiation therapy (PMRT) using proton pencil beam scanning (PBS).Method:Ten PMRT patients, with or without breast implant, underwent two helical CT scans: one with free breathing and the other with deep inspiration breath‐hold. A prescription of 50.4 Gy(RBE) to the whole chest wall and lymphatics (axillary, supraclavicular, and intramammary nodes) was considered. PBS plans were generated for each patient's CT scan using Astroid, an in‐house treatment planning system, with the institution conventional clinical PMRT parameters; that is, using a single en‐face field with a spot size varying from 8 mm to 14 mm as a function of energy. Similar optimization parameters were used in both plans in order to ensure appropriate comparison.Results:Regardless of the technique (free breathing or DIBH), the generated plans were well within clinical acceptability. DIBH allowed for higher target coverage with better sparing of the cardiac structures. The lung doses were also slightly improved. While the use of DIBH techniques might be of interest, it is technically challenging as it would require a fast PBS delivery, as well as the synchronization of the beam delivery with a gating system, both of which are not currently available at the institution.Conclusion:DIBH techniques display some dosimetric advantages over free breathing treatment for PBS PMRT patients, which warrants further investigation. Plans will also be generated with smaller spot sizes (2.5 mm to 5.5 mm and 5 mm to 9 mm), corresponding to new generation machines, in order to further quantify the dosimetric advantages of DIBH as a function of spot size.

SU-F-207-15: Band-Limited Noise Structure Analysis On Images With Adaptive Statistical Iterative Reconstruction (ASIR) in Abdominal CT

Purpose: To investigate the noise details in ASIR reconstructed images with regard to location and signal dependency and distribution normality in abdominal CT scans. Methods: A realistically shaped abdomen phantom (CIRS TE-07). The phantom was customized to allow for the insert of a low contrast module (CIRS 700 QA). Helical CT scans (120 kV, pitch 1.375, and thickness 5 mm) were performed on a GE 750 HD at two dose levels of 8 mGy and 18 mGy. The images were reconstructed using different ASIR fractions (0–100%). The noise images, obtained using subtraction from adjacent slices, were partitioned into different scales using matrices of square cells sized differently. The noise granularities were quantified by the standard deviation of the matrix cell pixel means distribution at each cell size. For each ASIR blending fraction, the following noise granularity properties were examined: the dependency on the matrix location and the dependency on the low contrast signal. The Komogorov-Smirnov normality test was performed on the matrix cell pixel means distributions. Results: For each ASIR blending fraction, the standard deviation of the matrix cell means distribution at each cell size was found independent of the matrix location. Furthermore, it does not vary due to the presence of the low contrast signal. The normality tests demonstrated that the cell means distributions are significantly drawn from Gaussian at the 0.05 level. Conclusion: The noise granularity independency on matrix location with ASIR reconstructed images suggests bigger matrices can be used for a better statistical description of the noise. The noise granularity independency on low contrast signal suggests that noise detail analysis can be done in a bigger area in the absence of the signal. Finally, the Gaussian distribution of the matrix cell means lends itself to statistically defining the minimum detectable contrast.

SU‐E‐T‐520: Investigation of the Impact of Respiratory Motion On Spine SAbR Dose Distributions

PurposeSpine SRS/SAbR treatment plans typically require very steep dose gradients to meet spinal cord constraints and it is crucial that the dose distribution be accurate. However, these plans are typically calculated on helical free‐breathing CT scans, which often contain motion artifacts. While the spine itself doesn't exhibit very much intra‐fraction motion, tissues around the spine, particularly the liver, do move with respiration. We investigated the dosimetric effect of liver motion on dose distributions calculated on helical free‐breathing CT scans for spine SAbR delivered to the T and L spine.MethodsWe took 5 spine SAbR plans and used density overrides to simulate an average reconstruction CT image set, which would more closely represent the patient anatomy during treatment. The value used for the density override was 0.66 g/cc. All patients were planned using our standard beam arrangement, which consists of 13 coplanar step and shoot IMRT beams. The original plan was recalculated with the same MU on the “average” scan and target coverage and spinal cord dose were compared to the original plan.ResultsThe average changes in minimum PTV dose, PTV coverage, max cord dose and volume of cord receiving 10 Gy were 0.6%, 0.8%, 0.3% and 4.4% (0.012 cc), respectively.ConclusionSAbR spine plans are surprisingly robust relative to surrounding organ motion due to respiration. Motion artifacts in helical planning CT scans do not cause clinically significant differences when these plans are re‐calculated on pseudo‐average CT reconstructions. This is likely due to the beam arrangement used because only three beams pass through the liver and only one beam passes completely through the density override. The effect of the respiratory motion on VMAT plans for spine SAbR is being evaluated.

SU-E-I-34: Evaluating Use of AEC to Lower Dose for Lung Cancer Screening CT Protocols

Purpose: The National Lung Screening Trial mandated manual low dose CT technique factors, where up to a doubling of radiation output could be used over a regular to large patient size range. Recent guidance from the AAPM and ACR for lung cancer CT screening recommends radiation output adjustment for patient size either through AEC or a manual technique chart. This study evaluated the use of AEC for output control and dose reduction. Methods: The study was performed on a multidetector helical CT scanner (Aquillion ONE, Toshiba Medical) equipped with iterative reconstruction (ADIR-3D), AEC was adjusted with a standard deviation (SD) image quality noise index. The protocol SD parameter was incrementally increased to reduce patient population dose while image quality was evaluated by radiologist readers scoring the clinical utility of images on a Likert scale. Results: Plots of effective dose vs. body size (water cylinder diameter reported by the scanner) demonstrate monotonic increase in patient dose with increasing patient size. At the initial SD setting of 19 the average CTDIvol for a standard size patient was ∼ 2.0 mGy (1.2 mSv effective dose). This was reduced to ∼1.0 mGy (0.5 mSv) at an SD of 25 with no noticeable reduction inmore » clinical utility of images as demonstrated by Likert scoring. Plots of effective patient diameter and BMI vs body size indicate that these metrics could also be used for manual technique charts. Conclusion: AEC offered consistent and reliable control of radiation output in this study. Dose for a standard size patient was reduced to one-third of the 3 mGy CTDIvol limit required for ACR accreditation of lung cancer CT screening. Gary Arbique: Research Grant, Toshiba America Medical Systems; Cecelia Brewington: Research Grant, Toshiba America Medical Systems; Di Zhang: Employee, Toshiba America Medical Systems.« less

TU-F-CAMPUS-J-05: Quantitative Evaluation of the Relationship Between Tissue Velocity and Motion-Artifacts of Free-Breathing Low-Dose Fast-Helical CT Scans

Purpose: The process of characterizing breathing motion has recently advanced by employing repeated fast-helical scans as the free-breathing CT images. While the scans are acquired using state-of-the-art CT scanners operating at nearly their highest couch-speeds, it still requires 0.23 s to scan any specific tissue-region. During quiet respiration, tissue velocities of up to 4 cm per second have been observed; leading to the residual motion-artifacts in the fast helical CT scans. This work evaluates the magnitude and characteristics of the motion-artifacts and correlates against model-calculated tissue velocities. Methods: 10 Patients were scanned 25 successive times using a low-dose fast-helical protocol with scans acquired in alternating directions. A 64-slice CT scanner with a pitch of 1.2 and table speed of 161.7 mm/s was used. The first scan was selected as the reference scan and deformable registrations were performed to register the other 24 scans to the reference scan. Motion-blur was quantified using blurring metrics and doubling-artifacts were further quantified using edge-response width to determine the mean edge-width of each lung diaphragm. The model-predicted velocities were correlated against the quantified artifacts. Results: Motion-artifacts appeared with the increased tissue velocity, from artifact-free to blurring-artifacts and then doubling-artifacts. Increasing amounts of doubling-artifacts were observed with tissue velocities > 18.2±1.3 mm/s. Regional blurring-artifacts occurred with velocities > 3.8±2.3 mm/s. The relationship between tissue velocity and motion-artifact severity was linear. There was no statistically significant difference in artifact magnitude between inhalation and exhalation phases. Conclusion: In spite of employing fast-helical acquisition with table speeds of 161.7 mm/s, motion-artifacts remained. The relationship between motion-artifact amplitude and tissue-velocity was linear with free-breathing fast-helical scans. This relationship will be used to aid in reference image selection, guide 5DCT accuracy assessments, and determine which images are averaged to produce the reference phase image used for treatment planning.

SU‐E‐E‐09: The Novel Investigation of the Accuracy of Image Position for Liver During Respiration in Helical CT

Purpose:To assess the image position of liver along the Z‐axis in helical CT compared to 4D CT and to evaluate the imaging similarity of helical CT and different phases of 4D CT for liver during respiration.Methods:Eleven patients with whole liver scanning during free breath in both helical CT and 4D CT were investigated. Eleven representative points ₍in liver segment 1, 2, 3, 4a, 4b, 5, 6, 7, 8, main portal vein, liver dome₎ were drew in helical CT image and adaptive deformed to 4D CT image, including the phase of end‐inspiration ₍phase 0₎ and end‐expiration ₍phase 50₎, using SmartAdapt in Eclipse™ version 11.5. Distances along the Z‐axis of the 11 points from helical CT to phase 0 CT, helical CT to phase 50 CT were measured, which represented the similarity of helical CT and end‐inspiration CT, helical CT and end‐expiration CT, respectively, for liver.Results:Mean distance along the Z‐axis from helical CT to phase 0 CT is ‐2.4±1.3 ₍mean±SD₎₍mm₎, which is the average of the 11 points ₍S1:‐2.5±4.6, S2:‐2.5±5.1, S3:‐4.0±3.2, S4a:‐0.9±4.4, S4b:‐2.9±4.1, S5:‐2.0±2.5, S6:‐3.6±3.3, S7:‐3.6±4.3, S8:‐1.8±3.9, main portal vein:‐3.4±4.1, liver dome:0.3±4.1₎. Mean distance from helical CT to phase 50 CT is 3.9±1.6 ₍S1:3.0±4.2, S2:3.2±3.8, S3:2.1±1.9, S4a:1.4±3.6, S4b:3.7±3.9, S5:3.7±2.7, S6:3.9±3.3, S7:6.0±5.0, S8:3.7±3.8, main portal vein:4.8±4.8, liver dome:7.1±5.9₎.Conclusion:Surprisingly, the image of helical CT scanning at random during free breath is more similar to the image at end‐inspiration, which is not corresponding to human physiology. Moreover, the helical CT image at liver dome is even beyond the image at end‐inspiration.

SU‐E‐J‐156: Velocity‐Based Reference Scan Selection for Motion‐Model Error Reduction of 5DCT

Purpose:A recently proposed 5DCT protocol uses fast helical CT scans to model lung tissue motion that requires one of the scans to be used as a reference for deformable image registration. We have found that, while the CT scans are acquired using fast helical acquisition, residual motionartifacts remain for scans acquired during mid inspiration or exhalation. Selecting the scan with minimal motion artifacts as the reference scan will improve image registration and model accuracy.Methods:A free‐breathing patient was scanned 25 successive times in alternating directions with a Siemens 64‐slice CT scanner using a low‐mA fast‐helical protocol. Each of the 25 CT scans was successively used as the reference scan with the other 24 images registered to it. Motion‐model parameters were determined using the breathing‐motion model. Voxel specific tissue velocity maps were generated for each of the 25 scan based on the breathing amplitude surrogate and its time derivative. The resulting 24 model error maps were registered to the first CT scan for comparison. The relationships between regional motion‐model error, reference scan motion‐artifacts and tissue‐velocity were analyzed using linear‐regression.Results:Motion‐model errors were linearly correlated with reference scan blurring artifacts and doubling artifacts. The effects of blurring‐artifacts on motion model errors were stronger than doubling artifacts due to their impact on registration accuracy. Selecting the lowest tissue motion velocity scan as the reference scan decreased the regional motion model error by 33.67%±43.12%.Conclusion:Motion‐artifacts, especially blurring artifacts, that exist in the reference image induce motion model errors in 5DCT. A carefully selected reference scan based on the lowest tissue velocities can minimize the regional motion model error.

Helical 4D CT pitch management for the Brilliance CT Big Bore in clinical practice.

In external beam radiotherapy treatment planning for patients with thoracic malignancies, respiratory‐correlated CT (4D CT) is used to obtain high quality studies in the presence of respiratory motion. When helical 4D CT scans are acquired with a Brilliance CT Big Bore, the pitch must meet two conditions. It must be low enough to avoid motion artifacts, and high enough to cover the entire scan length within 120 s to prevent overheating of the X‐ray tube. We developed a nomogram that can be used to obtain a suitable pitch satisfying both requirements. We also assessed the effects on the image quality of a pitch that exceeds the maximum pitch, and of a field of view (FOV) reduction. It was shown that, for AV G and MIP reconstructions, the manufacturer's maximum pitch equation yields an underestimation due to its FOV term.PACS number: 87.57.Q‐, 87.57.cp

DIAGNOSTIC VALUE OF NON-CONTRAST HELICAL CT-SCAN AND INTRAVENOUS UROGRAPHY IN UROLITHIASIS EVALUATION

Objective: To evaluate the diagnostic value of Non Contrast Helical Computed Tomography (NCHCT) scanning as the first choice diagnostic modality for detecting urolithiasis cases in Soetomo General Hospital Surabaya and evaluate the feasibility as alternative to Intravenous Urography (IVU). Material & Methods: Seventeen patients with clinical manifestation of suspected urolithiasis underwent NCHCT and IVU to evaluate suspected urolithiasis. Reformatted three-dimensional CT was performed in all patients. The images were correlated with findings from surgical procedure (ureteroscopy, percutaneous nephrolithotomy, and open surgery). Sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy were determined for NCHCT and IVU. Results: The diagnosis of urolithiasis was defined as unequivocal evidence of urolithiasis on either NCHCT or IVU. Sixteen of seventeen patients evaluated were diagnosed with urolithiasis. NCHCT established the diagnosis in 16 of 17 patients while IVU was positive in 11 of 17 patients. IVU was negative in 6 of the 17 cases. The sensitivity, specificity and accuracy of NCHCT was 100%, 100%, and 100% respectively (p = 0.05) and the sensitivity, specificity, and accuracy of IVU was 68%, 100% and 70% respectively (p = 0.35). There was no statistically significant difference between IVU and NCHCT using Fisher’s exact test. Conclusions: NCHCT accurately diagnosed urolithiasis in patients with suspected urolithiasis. Considering that NCHCT is more effective and efficient than IVU as diagnostic modality in determining the presence of urolithiasis, it may be considered to replace IVU as the first line diagnostic tool for urolithiasis in Soetomo General Hospital Surabaya.
 Keywords: Non Contrast Helical CT Scan, Intravenous Urography, Urolithiasis.

Performance tests for ray-scan 64 PET/CT based on NEMA NU-2 2007

This paper focuses on evaluating the performance of the Ray-Scan 64 PET/CT system, a newly developed PET/CT in China. It combines a 64 slice helical CT scanner with a high resolution PET scanner based on BGO crystals assembled in 36 rings. The energy window is 350∼ 650 keV, and the coincidence window is set at 12 ns in both 2D and 3D mode. The transaxial field of view (FOV) is 600 mm in diameter, and the axial FOV is 163 mm. Method: Performance measurements were conducted focusing on PET scanners based on NEMA NU-2 2007 standard. We reported the full characterization (spatial resolution, sensitivity, count rate performance, scatter fraction, accuracy of correction, and image quality) in both 2D and 3D mode. In addition, the clinical images from two patients of different types of tumor were presented to further demonstrate this PET/CT system performance in clinical application. Results: using the NEMA NU-2 2007 standard, the main results: (1) the transaxial resolution at 1cm from the gantry center for 2D and 3D was both 4.5mm (FWHM), and at 10cm from the gantry center, the radial (tangential) resolution were 5.6mm (5.3mm) and 5.4mm (5.2mm) in 2D and 3D mode respectively. The axial resolution at 1cm and 10cm off axis was 3.4mm (4.8mm) and 5.5mm (5.8mm) in 2D (3D) mode respectively; (2) the sensitivity for the radial position R0(r=0mm) and R100(r=100mm) were 1.741 kcps/MBq and 1.767 kcps/MBq respectively in 2D mode and 7.157 kcps/MBq and 7.513 kcps/MBq in 3D mode; (3) the scatter fraction was calculated as 18.36% and 42.92% in 2D and 3D mode, respectively; (4) contrast of hot spheres in the image quality phantom in 2D mode was 50.33% (52.87%), 33.34% (40.86%), 20.64% (26.36%), and 10.99% (15.82%), respectively, in N=4 (N=8). Besides, in clinical study, the diameter of lymph tumor was about 2.4 cm, and the diameter of lung cancer was 4.2 cm. This PET/CT system can distinguish the position of cancer easily. Conclusion: The results show that the performance of the newly developed PET/CT system is of high resolution, and low scatter characteristics, and is suitable for clinical applications.

Objective function to obtain multiple representative waveforms for a novel helical CT scan protocol.

To develop objective functions for selecting multiple representative respiratory waveforms. A specific application considered is to reduce the number of swiping scans in a novel helical CT scan protocol to harvest efficiency and dose reduction benefit. The authors consider a general class of potential objective functions consisting of weighted norms on pointwise profile differentials. The authors utilize the Lagrangian approach and derive proper conditions on the formulation based on first and second order optimality conditions. The derived objective functions are applied to clinically acquired respiratory trajectories for swipe subset selection to verify the validity and generality of the proposed rationale. An end-to-end 4DCT reconstruction comparison is performed using a swipe subset of data corresponding to 3 out of the full 25 waveforms to assess the consequence in image quality and dose. Their results show that maximizing the proposed objective function with the suggested parameters yields maximal spread of trajectories among the selected subset. 4DCT Reconstruction using the chosen subset of data indicates the potential for further dose reduction by about 5 to 10 folds without significant sacrifice in image quality. Experimental results also support further generalization to include slice prioritization. The authors have derived a formulation that is both simple and general as a metric to quantify the spread of a set of respiratory trajectories, which can be used for subset selection with potential computation and dose reduction benefit when applied to a newly developed helical 4DCT scan protocol.

Multidetector Computed Tomography Pulmonary Angiography Pitfalls in the Evaluation of Pulmonary Embolism With Emphasis in Technique

Pulmonary embolism (PE) is considered the third most common acute cardiovascular disease after myocardial infarction and stroke.Most preventable deaths associatedwith PE can be attributed to missed diagnosis, rather than therapy failure; thus, accurate and fast diagnosis of PE is important and greatly influences patient outcome. Computed tomography pulmonary angiography (CTPA) was first introduced as a diagnostic test for PEwith the arrival of helical CT scanners in the early 1990s. Less than a decade later, with improvements in resolution, acquisition speed, and image quality, multidetector CTPA (MDCTPA) became the most used diagnostic modality in the evaluation of PE. In 2007, the Fleischner Society declared that MDCTPA had fulfilled the conditions to replace conventional pulmonary angiography as the standard of reference for diagnosing acute PE. The recent introduction of dual-source MDCT technology adds functional assessment to the established anatomical evaluation, potentially further enhancing the capability of CTPA to determine the presence and clinical significance of pulmonary thromboembolism. The sensitivity and specificity for the diagnosis of PE since the era of single-slice helical CTPA has improved from 53%91% and 78%-97%, respectively, to 83%-100% and 89%97%, respectively, with MDCTPA. Several studies on single-slice and early-generation MDCTPA have reported “indeterminate” results ranging from 0.5%-10%, with a mean at approximately 6%. In a more recent study with 40-slice MDCT, 3.2% of 220 consecutive reports were deemed

Traumatic diaphragmatic rupture with combined thoracoabdominal injuries: Difference between penetrating and blunt injuries

PurposeTraumatic diaphragmatic rupture (TDR) needs early diagnosis and operation. However, the early diagnosis is usually difficult, especially in the patients without diaphragmatic hernia. The objective of this study was to explore the early diagnosis and treatment of TDR. MethodsData of 256 patients with TDR treated in our department between 1994 and 2013 were analyzed retrospectively regarding to the diagnostic methods, percentage of preoperative judgment, incidence of diaphragmatic hernia, surgical procedures and outcome, etc. Two groups were set up according to the mechanism of injury (blunt or penetrating). ResultsOf 256 patients with a mean age of 32.4 years (9–84), 218 were male. The average ISS was 26.9 (13–66); and shock rate was 62.9%. There were 104 blunt injuries and 152 penetrating injuries. Preoperatively diagnostic rate was 90.4% in blunt injuries and 80.3% in penetrating, respectively, P < 0.05. The incidence of diaphragmatic hernia was 94.2% in blunt and 15.1% in penetrating respectively, P < 0.005. Thoracotomy was performed in 62 cases, laparotomy in 153, thoracotomy plus laparotomy in 29, and combined thoraco-laparotomy in 12. Overall mortality rate was 12.5% with the average ISS of 41.8; and it was 21.2% in blunt injuries and 6.6% in penetrating, respectively, P < 0.005. The main causes of death were hemorrhage and sepsis. ConclusionsDiagnosis of blunt TDR can be easily obtained by radiograph or helical CT scan signs of diaphragmatic hernia. For penetrating TDR without hernia, “offside sign” is helpful as initial assessment. CT scan with coronal/sagittal reconstruction is an accurate technique for diagnosis. All TDR require operation. Penetrating injury has a relatively better prognosis.

Safety and biodistribution study of bone marrow–derived mesenchymal stromal cells and mononuclear cells and the impact of the administration route in an intact porcine model

Background aimsBone marrow mononuclear cells (BM-MNCs) and bone marrow–derived mesenchymal stem stromal cells (BM-MSCs) could have therapeutic potential for numerous conditions, including ischemia-related injury. Cells transplanted intravascularly may become entrapped in the lungs, which potentially decreases their therapeutic effect and increases the risk for embolism. MethodsTwelve pigs were divided into groups of 3 and received 99mTc- hydroxymethyl-propylene-amine-oxime–labeled autologous BM-MNCs or allogeneic BM-MSCs by either intravenous (IV) or intra-arterial (IA) transplantation. A whole body scan and single photon emission computed tomography/computed tomography (SPECT/CT) were performed 8 h later, and tissue biopsies were collected for gamma counting. A helical CT scan was also performed on 4 pigs to detect possible pulmonary embolism, 2 after IV BM-MSC injection and 2 after saline injection. ResultsThe transplantation route had a greater impact on the biodistribution of the BM-MSCs than the BM-MNCs. The BM-MNCs accumulated in the spleen and bones, irrespective of the administration route. The BM-MSCs had relatively higher uptake in the kidneys. The IA transplantation decreased the deposition of BM-MSCs in the lungs and increased uptake in other organs, especially in the liver. Lung atelectases were frequent due to mechanical ventilation and attracted transplanted cells. CT did not reveal any pulmonary embolism. ConclusionsBoth administration routes were found to be safe, but iatrogenic atelectasis might be an issue when cells accumulate in the lungs. The IA administration is effective in avoiding pulmonary entrapment of BM-MSCs. The cell type and administration method both have a major impact on the acute homing.

The use of positron emission tomography/computed tomography imaging in radiation therapy: a phantom study for setting internal target volume of biological target volume.

BackgroundFluorodeoxyglucose (18F-FDG) positron emission tomography/computed tomography (PET/CT) is an important method for detecting tumours, planning radiotherapy treatment, and evaluating treatment responses. However, using the standardized uptake value (SUV) threshold with PET imaging may be suitable not to determine gross tumour volume but to determine biological target volume (BTV). The aim of this study was to extract internal target volume of BTV from PET images.MethodsThree spherical densities of 18F-FDG were employed in a phantom with an air or water background with repetitive motion amplitudes of 0–30 mm. The PET data were reconstructed with attenuation correction (AC) based on CT images obtained by slow CT scanning (SCS) or helical CT scanning (HCS). The errors in measured SUVmax and volumes calculated using SUV threshold values based on SUVmax (THmax) in experiments performed with varying extents of respiratory motion and AC were analysed.ResultsA partial volume effect (PVE) was not observed in spheres with diameters of ≥ 28 mm. When calculating SUVmax and THmax, using SCS for AC yielded smaller variance than using HCS (p < 0.05). For spheres of 37- and 28-mm diameters in the phantom with either an air or water background, significant differences were observed when mean THmax of 30-, 20-, or 10-mm amplitude were compared with the stationary conditions (p < 0.05). The average THmax values for 37-mm and 28-mm spheres with an air background were 0.362 and 0.352 in non-motion, respectively, and the mean THmax values for 37-mm and 28-mm spheres with a water background were 0.404 and 0.387 in non-motion and 0.244 and 0.263 in motion, respectively. When the phantom background was air, regardless of sphere concentration or size, THmax was dependent only on motion amplitude.ConclusionsWe found that there was no PVE for spheres with ≥ 28-mm diameters, and differences between SUVmax and THmax were reduced by using SCS for AC. In the head-and-neck and the abdomen, the standard values of THmax were 0.25 and 0.40 with and without respiratory movement, respectively. In the lungs, the value of THmax became the approximate expression depending on motion amplitude.

Evaluation and management of blunt traumatic aortic injury: a practice management guideline from the Eastern Association for the Surgery of Trauma.

Blunt traumatic aortic injury (BTAI) is the second most common cause of death in trauma patients. Eighty percent of patients with BTAI will die before reaching a trauma center. The issues of how to diagnose, treat, and manage BTAI were first addressed by the Eastern Association for the Surgery of Trauma (EAST) in the practice management guidelines on this topic published in 2000. Since that time, there have been advances in the management of BTAI. As a result, the EAST guidelines committee decided to develop updated guidelines for this topic using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) framework recently adopted by EAST. A systematic review of the MEDLINE database using PubMed was performed. The search retrieved English language articles regarding BTAI from 1998 to 2013. Letters to the editor, case reports, book chapters, and review articles were excluded. Topics of investigation included imaging to diagnose BTAI, type of operative repair, and timing of operative repair. Sixty articles were identified. Of these, 51 articles were selected to construct the guidelines. There have been changes in practice since the publication of the previous guidelines in 2000. Computed tomography of the chest with intravenous contrast is strongly recommended to diagnose clinically significant BTAI. Endovascular repair is strongly recommended for patients without contraindications. Delayed repair of BTAI is suggested, with the stipulation that effective blood pressure control must be used in these patients.

AKILE™ total ankle arthroplasty: Clinical and CT scan analysis of periprosthetic cysts

IntroductionDespite good clinical results following total ankle replacement (TAR), the development of large periprosthetic cysts (>400 mm2) in the medium-term is a source of concern. ObjectiveThe primary objective of this study was to detect any large periprosthetic cysts in a cohort of AKILE™ patients using radiographs and CT scans, and then to compare these findings to published ones. Material and methodsA total of 127 TAR procedures were performed between June 1995 and January 2012. We retrospectively reviewed 68 cases with the newest AKILE™ implant design that had a minimum follow-up of 36 months. The average follow-up was 81±33 months; eight patients were lost to follow-up. The outcomes consisted of analyzing radiographs (A/P and lateral weight bearing views, Meary view and lateral views of flexion/extension) and helical CT scans, performing clinical evaluations (range of motion, AOFAS score, Foot Function Index, pain levels) and determining the survivorship of TAR implants. ResultsTAR survival at 5 years was 79% for in situ implants and 62% for revision-free implants. The AOFAS score improved from 33.7±14.7 to 77.1±15.1 (out of 100) and the pain sub-score was 30.2±9.7 (out of 40) at the last follow-up. The average ankle range of motion was 32.3°±12.7° on the radiographs. CT scan revealed Type A cysts (<200 mm2) under the talar implant in 52% of cases and in the tibia in 50% of cases; these cysts were smaller than 100 mm2 in 80% of cases and had no effect on the implants. No periprosthetic cysts larger than 400 mm2 in size were identified. DiscussionThe medium-term functional results and survivorship are comparable to those reported for other TAR designs. The incidence of cysts was low overall and there were no large-diameter cysts, which should improve long-term survival. The implant's design and materials likely played a role in preserving the periprosthetic bone stock. The AKILE™ TAR has distinctive features related to the low rate of large periprosthetic cysts in the medium-term. Level of evidenceIV (retrospective case series).