Conventional Static Imaging Research Articles

Targeted four-dimensional computerized tomography scans for elbow disorders: a literature review and refinement of existing technique with two exemplar cases

Background4D-CTs or motion CTs in elbow disorders have several potential advantages over conventional static imaging such as a reduction of misdiagnoses, a more targeted surgical approach, better patient understanding of their condition and potentially faster operative times. However, the radiation dose is higher than conventional static CT scans so this should be used judiciously. Our study reviews the current literature for 4D-CTs in dynamic elbow disorders and provides a technical note describing radiation-reduced targeted elbow 4D-CTs (te4D-CT) with two exemplar cases alongside our recommendations for when te4D-CTs are indicated. Methodste4D-CTs are performed in a lateral decubitus elbow above head position. Preliminary static source axial cut CT obtained with subsequent sagittal and axial planes reconstruction and 3D reconstruction obtained, followed by scan performed in motion and reconstructed to 4D Component. te4D-CTs are taken for either flexion and extension (FE) or pronation and supination (PS) motions depending on the clinical pathology suspected following thorough clinical examination. Resultste4D-CT for PS and FE protocol scans had an effective radiation exposure dose of 0.53 and 0.95mSv respectively compared to 1.13-1.83mSv in conventional elbow 4D-CTs. In addition, te4D-CTs have good diagnostic accuracy provided that the FE or PS pathology is identified carefully by the ordering physician. Conclusionte4D-CT using isolated pronation and supination, or flexion and extension protocols does come with a significantly reduced radiation dose and can be of equal clinical yield compared with 4D-CTs.

A Shortened Model for Logan Reference Plot Implemented via the Self-Supervised Neural Network for Parametric PET Imaging.

Dynamic PET imaging provides superior physiological information than conventional static PET imaging. However, the dynamic information is gained at the cost of a long scanning protocol; this limits the clinical application of dynamic PET imaging. We developed a modified Logan reference plot model to shorten the acquisition procedure in dynamic PET imaging by omitting the early-time information necessary for the conventional reference Logan model. The proposed model is accurate theoretically, but the straightforward approach raises the sampling problem in implementation and results in noisy parametric images. We then designed a self-supervised convolutional neural network to increase the noise performance of parametric imaging, with dynamic images of only a single subject for training. The proposed method was validated via simulated and real dynamic 18F-fallypride PET data. Results showed that it accurately estimated the distribution volume ratio (DVR) in dynamic PET with a shortened scanning protocol, e.g., 20 minutes, where the estimations were comparable with those obtained from a standard dynamic PET study of 120 minutes of acquisition. Further comparisons illustrated that our method outperformed the shortened Logan model implemented with Gaussian filtering, regularization, BM4D and the 4D deep image prior methods in terms of the trade-off between bias and variance. Since the proposed method uses data acquired in a short period of time upon the equilibrium, it has the potential to add clinical values by providing both DVR and Standard Uptake Value (SUV) simultaneously. It thus promotes clinical applications of dynamic PET studies when neuronal receptor functions are studied.

Bony Stroke: Ischemic Stroke Caused by Mechanical Stress on Brain Supplying Arteries From Anatomical Bone or Cartilage Anomalies

Bone or cartilage anomalies with affection of brain supplying arteries are a potential structural cause for ischemic stroke. In the following, we termed this entity bony stroke. Due to rarity of their description, there is no standardized workup and therapy for bony strokes. Retrospectively, we extracted diagnostic and therapeutic workup of all patients considered to have had a bony stroke between January 2017 to March 2022 at our comprehensive care center. In total, 6 patients classified as a bony stroke were identified among 4200 acute patients with ischemic stroke treated during the study period. Each patient had recurrent ischemic strokes in the dependent vascular territory before diagnosis. Diagnosis was achieved by a combination of imaging devices, including sonography, computed tomography, and magnetic resonance imaging. In addition to conventional static imaging, the application of dynamic imaging modalities with the patients' head in rotation or reclination confirmed a vessel affection following head movements in 3 patients (50%). Treatment options were interdisciplinary assessed and included the following: conservative treatment (n=1), endovascular stenting (n=2) or occlusion (n=2), surgical removal of bone/ cartilage (n=2), and surgical bypass treatment (n=1). In follow-up (mean 11.7 months), no patient experienced further ischemia. As a differential diagnosis, bony strokes may be considered in patients with recurrent ischemic stroke of unknown cause in one dependent vascular territory. Interdisciplinary evaluation and treatment may eliminate risk of stroke recurrence.

P49. Proposal of a new standardized method to evaluate spine flexibility using the EOSEdge® low dose radiation imaging for thoracolumbar flexion extension

<h3>BACKGROUND CONTEXT</h3> Thoraco-lumbar vertebral mobility is one of the key parameters that must be analyzed when planning a spinal surgery for spinal deformity. In 1989, Putto et al. published the first radiological procedure to get a 2D X-ray acquisition of patient in a flexion/extension posture of the spine. To date, no similar procedure has been applied to new imaging modality such as the 3D stereoradiography (EOSEdge® imaging) which allow a 3D reconstruction of the spine according to the ALARA concept. <h3>PURPOSE</h3> This study aims to propose a new standardized method to evaluate the vertebral mobility based on the dynamic X-ray using a reproducible method applied to the EOSEdge® imaging technology called. An institutional IRB was obtained for this prospective study. <h3>STUDY DESIGN/SETTING</h3> Observational cohort study. <h3>PATIENT SAMPLE</h3> Fifty patients requested a surgery for spinal deformity. <h3>OUTCOME MEASURES</h3> Intervertebral lordosis and vertebral cobb angle from T11 to S1 were measured individually to assess spine mobility. <h3>METHODS</h3> Candidates for an instrumented spinal surgery had a pre-operative full-spine flexion-extension acquisition according to the predefined protocol using two radiolucent supports that were easy to put in the EOS frame. Extension of the spine was obtained using a height adjustable walker placed behind the patient in the EOS machine allowing stable and safe positioning with limited pain. Patients were then asked to bend backward and keep their position during the acquisition process. To get a full-spine flexion acquisition, patients were seated on a stool and bent forward during the EOS acquisition. Radiographic parameters such as lumbar intervertebral angulation (angulation of each lumbar and thoracic discs) and lumbar lordosis or thoracic kyphosis were analyzed to get a quantitative representation of the spine flexibility. <h3>RESULTS</h3> A total of 50 patients were included in this protocol. Positioning the patients were highly reproducible using external skin landmarks that matched with skeleton anatomy on final images. Comparison of measures between flexion and extension to regular full spine standing imaging showed significant motion and abnormal mobility at some levels not visible in static standing. Limited motion was commonly seen in degenerative spine. <h3>CONCLUSIONS</h3> This study proposes a new standardized method to analyze the spinal flexibility using the EOSEdge® imaging technique. This method can be applied safely to allow detection of abnormal vertebral mobility and therefore a better analysis of spondylolisthesis and degenerative disc disease, which could not be assessed using other conventional static imaging techniques. <h3>FDA DEVICE/DRUG STATUS</h3> This abstract does not discuss or include any applicable devices or drugs.

Determination of optimal 68Ga-PSMA PET/CT imaging time in prostate cancers by total-body dynamic PET/CT.

68Ga-PSMA PET/CT has been widely used in patients with prostate cancer. Due to the limited axial field of view of conventional PET scanners, whole-body dynamic 68Ga-PSMA PET/CT has not been performed. We investigated the time-activity curves (TACs) of prostate cancer pathological lesions and physiologic bladder activity to determine the optimal 68Ga-PSMA PET/CT imaging time by total-body (TB) PET/CT. Dynamic TB-PET performed on 11 patients with prostate cancer was analyzed. TACs were obtained by drawing regions of interest in normal organs and pathological lesions (primary prostate lesions and lymph nodes and bone metastases). We evaluated the 68Ga-PSMA uptake pattern of normal organs, urinary bladder, and pathological lesions. The urinary bladder TAC increased slowly between 180 and 330s post-injection and then rapidly between 5.5 and 60.0min post-injection. The pathological lesion uptake increased rapidly during the first 5min post-injection and then slowly through the remaining 55min. Six minutes post-injection was the optimal time with the highest pathological lesion SUVmean values still higher than the urinary bladder activity value. However, these prostate lesion, lymph node metastasis, and bone metastasis SUVmean values were one-third, one-half, and one-half the corresponding values 60min post-injection, suggesting that early imaging might miss low PSMA uptake lesions. A minimum of 35min post-injection was required for the pathological lesions to have SUVmean values similar to the corresponding values at 60min post-injection (all P > 0.05), even though the pathological lesion SUVmean values showed a continuous upward trend through the 60min. Combining early dynamic 68Ga-PSMA PET (75-360s) and conventional static imaging 60min post-injection could avoid the urinary bladder activity interference to better detect pathological lesions and lesions with relatively low PSMA uptake. The pathological lesion SUVmean values at 35-59min and 60min post-injection were similar, so 68Ga-PSMA PET imaging could also be made at 35-59min post-injection.

Assessing tumor metabolic heterogeneity of non-small cell lung cancer with total body PET-CT imaging on the uExplorer: Analysis of dynamic changes of 18F-FDG uptake.

e20549 Background: Total body positron emission tomography (PET) of uExplorer enables imaging of highly quantitative parameters beyond the standardized uptake value (SUV). The aim of this prospective study is to assess the dynamic changes of 2-deoxy-2-[18F]fluoro-D-glucose ([18F]FDG) uptake in characterizing tumor heterogeneity of non-small cell lung cancer (NSCLC). Methods: Sixteen NSCLC patients were prospectively enrolled in a prospective study (NCT04654234, GASTO-1067) between September 2020 and December 2020. All patients underwent a dynamic total-body 18F-FDG PET/CT scan before any treatment. The primary lung tumor, metastatic regional lymph node and inflammatory lymph node were manually delineated by a nuclear medicine physician and a radiation oncologist. Total Body PET was acquired between 0 – 60 mins after the injection of FDG from the subject’s feet. We compared lesion heterogeneity and different image-derived PET metrics including the SUV-mean, Patlak-derived influx rate constant (Ki) and distribution volume (DV). Results: The SUV-mean and Ki-mean of primary lung tumor and metastatic lymph node were significantly higher than inflammatory lymph node (p &lt; 0.001), while there was no significantly different of DV(p &gt; 0.05). By the scatter plot of SUV-mean and Ki-mean of primary lung tumor, 9 patients had been separated into high dynamic FDG metabolic (H-DFM) group and 7 in low DFM(L-DFM) group. The SUV-mean(p = 0.0002) and Ki-mean(p = 0.0002) of primary lung tumor were significantly higher in H-DFM group, whereas there is no difference in metastatic lymph node of both group. Interestingly, the SUV-mean and Ki-mean of primary lung tumor were higher than that of metastatic lymph node(p = 0.0002) in H-DFM group. On the contrast, the SUV-mean and Ki-mean of primary lung tumor were lower than that of metastatic lymph node(p = 0.05) in L-DFM group. There is no significant difference of DV-mean among primary lung tumor, metastatic lymph node and inflammatory lymph node in both arms. Conclusions: The results demonstrated that dynamic parameters from total body PET scan has the potential of providing complementary information of tumor heterogeneity in NSCLC than conventional static SUV imaging. The characteristics of H-DFM and L-DFM group could be taken into account for evaluation of further treatment response.

Application of Elasticity Imaging Techniques Based on Ultrasound in Breast Tumor Activity, Blood Supply, and Benign and Malignant Tumor Diagnosis

Objective: The purpose of the study is to discuss the application of ultrasound elasticity imaging techniques in the diagnosis of breast tumor activity, blood supply, benign and malignant tumor diagnosis, and help better diagnosing. Methods: 94 lesions of 84 femalebreast lesions patients were evaluated by conventional ultrasound and static ultrasound elasticity imaging techniques, including 29 malignant lesions and 65 benign lesions. The ultrasonic image was processed by image denoising algorithm. 5-point scale criteria were used to evaluate the elasticity of each lesion, and measure the strain rate (SR) and the mean value of strain color histogram of each lesion. The receiver operating characteristic curve (ROC) was used to analyze the diagnostic sensitivity, specificity, and area under the curve (Az) of various indicators, and evaluate the diagnostic value of conventional ultrasound, static ultrasound elastic imaging, and the combination of the two. Results: the highest Az value of 0.941 was obtained by combining the three static ultrasound elasticity imaging techniques, namely, scoring method, SR method, and strain color histogram method with conventional ultrasound. It was higher than that (0.891) based on conventional ultrasound breast image report and data system (BI-RADS). Moreover, the diagnosis sensitivity was significantly improved, and the specificity was basically unchanged. Conclusion: the combination of static ultrasound elasticity imaging techniques and conventional ultrasound can reduce the number of benign breast lesions and avoid the omission of malignant lesions requiring biopsy. Static ultrasound elasticity imaging techniques are helpful to distinguish the breast lesions. It can be used as a supplement to conventional ultrasound and improve the diagnostic efficiency of ultrasound.

Effectively Measuring Exercise-Related Variations in T1ρ and T2 Relaxation Times of Healthy Articular Cartilage.

Determining the compositional response of articular cartilage to dynamic joint-loading using MRI may be a more sensitive assessment of cartilage status than conventional static imaging. However, distinguishing the effects of joint-loading vs. inherent measurement variability remains difficult, as the repeatability of these quantitative methods is often not assessed or reported. To assess exercise-induced changes in femoral, tibial, and patellar articular cartilage composition and compare these against measurement repeatability. Prospective observational study. Phantom and 19 healthy participants. 3T; 3D fat-saturated spoiled gradient recalled-echo; T1ρ - and T2 -prepared pseudosteady-state 3D fast spin echo. The intrasessional repeatability of T1ρ and T2 relaxation mapping, with and without knee repositioning between two successive measurements, was determined in 10 knees. T1ρ and T2 relaxation mapping of nine knees was performed before and at multiple timepoints after a 5-minute repeated, joint-loading stepping activity. 3D surface models were created from patellar, femoral, and tibial articular cartilage. Repeatability was assessed using root-mean-squared-CV (RMS-CV). Using Bland-Altman analysis, thresholds defined as the smallest detectable difference (SDD) were determined from the repeatability data with knee repositioning. Without knee repositioning, both surface-averaged T1ρ and T2 were very repeatable on all cartilage surfaces, with RMS-CV <1.1%. Repositioning of the knee had the greatest effect on T1ρ of patellar cartilage with the surface-averaged RMS-CV = 4.8%. While T1ρ showed the greatest response to exercise at the patellofemoral cartilage region, the largest changes in T2 were determined in the lateral femorotibial region. Following thresholding, significant (>SDD) average exercise-induced in T1ρ and T2 of femoral (-8.0% and -5.3%), lateral tibial (-6.9% and -5.9%), medial tibial (+5.8% and +2.9%), and patellar (-7.9% and +2.8%) cartilage were observed. Joint-loading with a stepping activity resulted in T1ρ and T2 changes above background measurement error. 2 TECHNICAL EFFICACY STAGE: 1 J. MAGN. RESON. IMAGING 2020;52:1753-1764.

Assessment of Lesion Detectability in Dynamic Whole-Body PET Imaging Using Compartmental and Patlak Parametric Mapping.

Hybrid dynamic imaging allows not only the estimation of whole-body (WB) macroparametric maps but also the estimation of microparameters in the initial bed position targeting the blood pool region containing the pathology owing to the limited axial field of view of PET scanners. In this work, we assessed the capability of multipass WB F-FDG PET parametric imaging in terms of lesion detectability through qualitative and quantitative evaluation of simulation and clinical studies. Simulation studies were conducted by generating data incorporating 3 liver and 3 lung lesions produced by 3 noise levels and 20 noise realizations for each noise level to estimate bias and lesion detection features. The total scan time for the clinical studies of 8 patients addressed for lung and liver lesions staging, including dynamic and static WB imaging, lasted 80 minutes. An in-house-developed MATLAB code was utilized to derive the microparametric and macroparametric maps. We compared lesion detectability and different image-derived PET metrics including the SUVs, Patlak-derived influx rate constant (Ki) and distribution volume (V) and K1, k2, k3, blood volume (bv) microparameters, and Ki estimated using the generalized linear least square approach. In total, 104 lesions were detected, among which 47 were located in the targeted blood pool bed position where all quantitative parameters were calculated, thus enabling comparative analysis across all parameters. The evaluation encompassed visual interpretation performed by an expert nuclear medicine specialist and quantitative analysis. High correlation coefficients were observed between SUVmax and Kimax derived from the generalized linear least square approach, as well as Ki generated by Patlak graphical analysis. Moreover, 3 contrast-enhanced CT-proven malignant lesions located in the liver and a biopsy-proven malignant liver lesion not visible on static SUV images and Patlak maps were clearly pinpointed on K1 and k2 maps. Our results demonstrate that full compartmental modeling for the region containing the pathology has the potential of providing complementary information and, in some cases, more accurate diagnosis than conventional static SUV imaging, favorably comparing to Patlak graphical analysis.

Interactive Panorama VR360 for Corporate Communications: An Industrial Scenario Case Study

This case study explores interactive panorama implementation for corporate communications virtual reality 360 (VR360) application. Interactive panorama permits spherical panorama digital imagery being presented in three hundred sixty degrees visual experience instead of single angle limitation in conventional static image. The study proposes the use of interactive panorama as a corporate communications tool being considered from three experimental PEP aspects. The exploration of PEP framework seeks the suitability of implementing three key aspects of people, equipment and product for interactive panorama virtual reality 360 experience. With the developing advances of interactive panorama, it has been introduced by online social media providers as essential feature which allows individual and corporate users to post 360 content. This case study takes advantage on the actual on-going marketing experience and technical insight of a participating case company and several industrial scenario use cases. In this paper we describe interactive panorama content creation, PEP framework, a user study and directions for future work.

De Novo Assessment of Pediatric Musculoskeletal Soft Tissue Tumors: Beyond Anatomic Imaging.

MRI plays a central role in the assessment of pediatric musculoskeletal soft tissue tumors. Although these neoplasms may initially be evaluated on other modalities, such as sonography, MRI is essential for accurately determining the extent of disease. Traditionally, MRI has been performed with sequences that provide excellent anatomic detail, with T1-weighted, fluid-sensitive, and static postcontrast T1-weighted sequences. However, with the introduction of noncontrast sequences such as diffusion-weighted imaging and magnetic resonance spectroscopy to the arsenal of available MRI techniques, functional and metabolic features of a neoplasm can now be examined noninvasively. These more recent MRI methods offer information for lesion characterization, the assessment of treatment response, and the distinction of postoperative scar from recurrence. Dynamic contrast-enhanced perfusion imaging is another useful functional technique that can be acquired before conventional static postcontrast imaging, without requiring additional contrast material. This review presents recent advances in MRI methodology that enable a comprehensive clinical assessment of musculoskeletal tumors in the pediatric population. The roles and challenges of combining anatomic, functional, and metabolic MRI sequences will be discussed as they relate to newly discovered soft tissue tumors in children.

An integrated bioimpedance—ECG gating technique for respiratory and cardiac motion compensation in cardiac PET

Respiratory motion may degrade image quality in cardiac PET imaging. Since cardiac PET studies often involve cardiac gating by ECG, a separate respiratory monitoring system is required increasing the logistic complexity of the examination, in case respiratory gating is also needed. Thus, we investigated the simultaneous acquisition of both respiratory and cardiac gating signals using II limb lead mimicking electrode configuration during cardiac PET scans of 11 patients. In addition to conventional static and ECG-gated images, bioimpedance technique was utilized to generate respiratory- and dual-gated images. The ability of the bioimpedance technique to monitor intrathoracic respiratory motion was assessed estimating cardiac displacement between end-inspiration and -expiration. The relevance of dual gating was evaluated in left ventricular volume and myocardial wall thickness measurements. An average 7.6 ± 3.3 mm respiratory motion was observed in the study population. Dual gating showed a small but significant increase (4 ml, p = 0.042) in left ventricular myocardial volume compared to plain cardiac gating. In addition, a thinner myocardial wall was observed in dual-gated images (9.3 ± 1.3 mm) compared to cardiac-gated images (11.3 ± 1.3 mm, p = 0.003). This study shows the feasibility of bioimpedance measurements for dual gating in a clinical setting. The method enables simultaneous acquisition of respiratory and cardiac gating signals using a single device with standard ECG electrodes.

Cardiac dynamic magnetic resonance of a giant lung carcinoma invading the left atrium: do not let the imaging fool you

This study aimed to report on a non-small-cell lung cancer (NSCLC) originating from the right lung lower lobe and circulatory extension into the left atrium. Atrial involvement is an uncommon feature of advanced NSCLC, occurring in up to 10% of patients with bronchogenic carcinoma. In this case, the neoplastic mass was enormous and diagnosed as a lung pleiomorph carcinoma, staged T4N2M0 and so far considered irresectable. Conventional static imaging (chest CT-positron emission tomography scan; cardiac MRI) failed to rule out any direct invasion into surrounding structures. Surgery is the gold standard treatment for the local control of NSCLC without distant metastasis. Finally, preoperative cardiac dynamic magnetic resonance imaging and transoesophageal echocardiography were crucial to assess resectability, showing the absence of tumour invasion inside the pulmonary circulation and in the left atrium, supporting the decision-making for a radical, curative, surgical resection.

“A horse, a horse, my kingdom for a horse” – Saddle thrombosis of carotid bifurcation in acute stroke

Saddle thrombosis is less frequently detected in carotid arteries than in peripheral arterial embolism. The clot and the distal vessel patency have to be promptly recognized in these cases, because if the carotid vessel is open distally, chances may arise for successful emergent surgical procedures to remove the thrombus. At conventional static imaging, mobile floating thrombi may be difficult to differentiate from thrombosis on carotid complicated lesions of atherosclerotic origin. High-resolution ultrasound (US), with its unique capability of real-time imaging, adds fundamental data for interpretation of the findings. Carotid ultrasound has been performed in acute stroke patients with high-resolution probes. Real-time clips are analyzed and imaging is presented. Saddle carotid bifurcation thrombosis of cardiac origin has been identified in 2 patients with acute homolateral ischemic stroke, with prompt successful surgical removal in one case. Moreover, an example of a thrombus attached on the ruptured surface of a complicated atherosclerotic plaque in an acute symptomatic stroke patient that was successfully operated in emergency is presented. Early high-resolution ultrasound with real-time imaging can easily identify peculiar characteristics of carotid vulnerable diseases in acute stroke phase. Different clinical implications result from the early identification of these different conditions, modifying the therapeutical strategies.

Frequency-difference electrical impedance tomography (fdEIT): algorithm development and feasibility study

Frequency-difference electrical impedance tomography (fdEIT) has been proposed to deal with technical difficulties of a conventional static EIT imaging method caused by unknown boundary geometry, uncertainty in electrode positions and other systematic measurement artifacts. In fdEIT, we try to produce images showing changes of a complex conductivity distribution with respect to frequency. Simultaneously injecting currents with at least two frequencies, we find differences of measured boundary voltages between those frequencies. In most previous studies, real parts of frequency-difference voltage data were used to reconstruct conductivity changes and imaginary parts to reconstruct permittivity changes. This conventional approach neglects the interplay of conductivity and permittivity upon measured boundary voltage data. In this paper, we propose an improved fdEIT image reconstruction algorithm that properly handles the interaction. It uses weighted frequency differences of complex voltage data and a complex sensitivity matrix to reconstruct frequency-difference images of complex conductivity distributions. We found that there are two major sources of image contrast in fdEIT. The first is a contrast in complex conductivity values between an anomaly and background. The second is a frequency dependence of a complex conductivity distribution to be imaged. We note that even for the case where conductivity and permittivity do not change with frequency, the fdEIT algorithm may show a contrast in frequency-difference images of complex conductivity distributions. On the other hand, even if conductivity and permittivity values significantly change with frequency, there is an example where we cannot find any contrast. The performance of the proposed method is demonstrated by using computer simulations to validate its feasibility in future experimental studies.

Bone marrow hypervascularity in patients with myelofibrosis identified by infra-red thermography

Infra-red thermography was used to assess bone marrow vascularity in six patients with myelofibrosis secondary to myeloproliferative disorders (four primary myelofibrosis and two primary proliferative polycythaemia). The technique was evaluated with conventional static and dynamic radio-isotopic imaging and with immunohistochemical staining of bone marrow biopsies. Infra-red thermography identified increased bone marrow blood flow in patients with established myelofibrosis and correlated with dynamic radio-isotopic studies of blood flow and hypervascularity identified by immunohistochemistry. Increased bone marrow blood flow and vascular proliferation was not confined to the central bone marrow but also extended into the peripheral marrow of the long bones. Endothelial cell proliferation may be an initiating event in the pathogenesis of myelofibrosis but evaluation of bone marrow vascularity and blood flow has hitherto relied on invasive and complicated techniques. This study has identified bone marrow hypervascularity in patients with myelofibrosis and shown infra-red thermography to be a simple non-invasive method of assessing vascularity. This non-invasive technique may be used to study disease progression and response to therapeutic regimens in patients with myelofibrosis and to study bone marrow blood flow in other bone marrow disorders.

Response assessment using dynamic MR imaging in non-metastatic osteosarcoma

10018 Background: Conventional static imaging methods are of limited utility in assessing osteosarcoma (OS) response to neoadjuvant chemotherapy primarily due to the lack of significant change in tumor size. Methods: We prospectively evaluated the utility of dynamic contrast-enhanced MR imaging (DEMRI) in assessing tumor response as part of a phase II trial of multiagent chemotherapy for treatment of OS from 1999 to 2006. Forty-two subjects (median age, 13.5 years) with non-metastatic OS of the extremity (27 femur, 10 tibia, 3 humerus, 1 fibula, and 1 ulna) underwent one or more DEMRI examinations and had histological assessment of tumor response. DEMRI was performed at baseline (before course 1 of chemotherapy [week 0]), at week 9 (after 3 courses of chemotherapy), and at week 12 (after 4 courses of chemotherapy before definitive surgery). Quantitative DEMRI measures reflecting rate and intensity of enhancement (dynamic vector magnitude [DVM]) and regional contrast transfer between the plasma and extracellular/extravascular spaces (kep) were analyzed in relation to histological response. Nonparametric Wilcoxon signed-rank test was used to compare DEMRI parameters during preoperative chemotherapy with baseline. Logistic regression was used to examine the association between DEMRI parameters and histological response at each time point. Results: Both DEMRI parameters at week 9 and at week 12 of preoperative chemotherapy were significantly decreased from baseline (p&lt;0.001). Patients with lower DVM or lower kep at week 9 or at week 12 ( Table ) were significantly more likely to have good histological response (&gt;90% tumor necrosis). Conclusions: DEMRI is a non-invasive method that can be used to assess tumor response to neoadjuvant chemotherapy in OS. A slower rate of contrast accumulation in the extracellular/extravascular space corresponds to increased tumor necrosis. [Table: see text] No significant financial relationships to disclose.

Electrical impedance imaging of two-phase flows undergoing rapid transient: Part I. Dynamic imaging

This study presents a visualization technique for the phase distribution in a two-phase flow field with electrical impedance imaging technique, which reconstructs the resistivity distribution with electrical responses that are determined by corresponding excitations. Special emphasis is placed on the development of dynamic imaging technique for two-phase system undergoing rapid transient, which could not be visualized with conventional static imaging techniques. The proposed algorithm treats the image reconstruction problem as a nonlinear state estimation problem and the unknown state (resistivity distribution, i.e. phase distribution) is estimated with the aid of Kalman filter in a minimum mean square error sense. With computer simulations, some issues arisen in the application to two-phase flows are discussed and the performance of the proposed algorithm is examined.

Assessment of Occult Pancreatobiliary Reflux by Biliary Amylase Levels in Patients with Pancreaticobiliary Disease

Assessment of Occult Pancreatobiliary Reflux by Biliary Amylase Levels in Patients with Pancreaticobiliary Disease Takao Itoi, Kazuto Nakamura, Atsushi Sofuni, Fumihide Itokawa, Kazuhiro Kakimi, Jun Sanada, Fuminori Moriyasu Objectives: Pancreatobiliary maljunction (PBM) is a high risk factor for biliary tract cancer. Carcinogenesis by PBMhas yet to be completely clarified; however, it has been suggested that the mixing of pancreatic juice and bile could activate pancreatic enzymes. Recently, however, several investigators reported existence of pancreatobiliary reflux in patients with a normal pancreaticobiliary junction. The aim of this study was to prospectively examine pancreatobiliary reflux in patients with a normal pancreaticobiliary junction by measuring the amylase level in bile obtained during ERCP. Methods: Eligible patients included 86 consecutive cases of pancreaticobiliary disease with prospective implementation of bile collection during an ERCP procedure. Patients with PBM were excluded. Nineteen cases of eligible patients had simultaneous collection of gallbladder bile. Bile was further collected by cholecystectomy in eight cases. Results: Twenty-two cases (26%) revealed a common bile duct higher than serum amylase (high bile amylase level HBA group) and sixty-six cases exhibited a common bile duct amylase level lower than serum (LBA group). The mean values of common bile duct amylase level in the HBA and LBA groups were 5,502 IU/L and 29 IU/L, respectively. The rate of HBA was significantly higher in patients who were elderly, had a dilated common bile duct, and with choledocholithiasis (p<0.05). Three cases (16%) showed a common bile duct amylase level greater than twice the gallbladder amylase level. Eleven cases (58%) exhibited a gallbladder amylase level higher than the common bile duct amylase level. The values of gallbladder amylase level obtained during ERCP and cholecystectomy were consistent. Conclusions: In conclusion, the data in our study suggested that non-PBMpatients with pancreaticobiliary disease that shows a normal pancreaticobiliary junction might have occult pancreatobiliary reflux under physiological conditions, thereby possibly leading to biliary diseases. *T1442 Importance of Real Time Interpretation (INTERP) of ERCP Films Over Conventional Static Images: Medicolegal Implications Miriam Thomas, Joseph E. Geenen, Marc F. Catalano ERCP is a complex procedure requiring technical skill, careful attention to endoscopic and radiographic (INTERP) that frequently requires evaluation of both real time & hard film copies. Although ERCP X-Rays are reviewed & formally reported by radiologist (RAD), gastroenterologist (GE) perform the studies & interpret fluoroscopic images. Differences in INTERP could lead to medicolegal liability. METHOD: ERCP records of 154 consecutive pts were prospectively evaluated.GE INTERP of ERCP films using real time&hard copies were documented & compared with available text documentation by RAD. Components of each exam were assessed for differences in final INTERP between GE andRAD. Biliary &pancreatic cases were reviewed for documentation of duct diameter, duct INTERP, strictures, stones, cytology, dilatation & stone removal. RESULT: Bile duct (BD) INTERP byGE&RADwere ABN&NL in 64%, 36% compared to 56%, 44% respectively. PD INTERP by GE was documented to be ABN in 63%, NL in 38% compared to 53% & 46% respectively by RAD. There was significant disagreement between GE & RAD regarding ductal INTERP (P<0.05). For the presence of BD stones, PD stones, BD stricture, PD stricture there was an agreement of 52%, 73%, 79% & 84% respectively. In therapeutic cases agreement between RAD & GE of BD cytology, duct dilation, stone removal, PD cytology, PDdilatation, PD stone removal was present in 73%, 50%, 32%, 53%, 44%, & 42% respectively. When compared to GE documentation RAD failed to document the CBD & PD diameter, 27% of BD cytology cases, 50% of biliary dilatation, 68% of BD stone removal, 47% of PD cytology, 55% of PD dilatation & 58%of PD stone removal. Under INTERP of findings frequently occurred in RAD dictated report when compared to GE. CONCLUSION: Many important aspects of the ERCP findings are under documented when interpreting findings using hard copies only. This could be due to lack of adequate film documentation of the procedure. The extent of documentation carries clinical & medicolegal importance. Careful reviews of both real time images & hard film copies are essential to ensure accurate final INTERP.

Importance of Real Time Interpretation (INTERP) of ERCP Films Over Conventional Static Images: Medicolegal Implications

ERCP is a complex procedure requiring technical skill, careful attention to endoscopic and radiographic (INTERP) that frequently requires evaluation of both real time & hard film copies. Although ERCP X-Rays are reviewed & formally reported by radiologist (RAD), gastroenterologist (GE) perform the studies & interpret fluoroscopic images. Differences in INTERP could lead to medicolegal liability. METHOD: ERCP records of 154 consecutive pts were prospectively evaluated. GE INTERP of ERCP films using real time & hard copies were documented & compared with available text documentation by RAD. Components of each exam were assessed for differences in final INTERP between GE and RAD. Biliary & pancreatic cases were reviewed for documentation of duct diameter, duct INTERP, strictures, stones, cytology, dilatation & stone removal. RESULT: Bile duct (BD) INTERP by GE & RAD were ABN & NL in 64%, 36% compared to 56%, 44% respectively. PD INTERP by GE was documented to be ABN in 63%, NL in 38% compared to 53% & 46% respectively by RAD. There was significant disagreement between GE & RAD regarding ductal INTERP (P<0.05). For the presence of BD stones, PD stones, BD stricture, PD stricture there was an agreement of 52%, 73%, 79% & 84% respectively. In therapeutic cases agreement between RAD & GE of BD cytology, duct dilation, stone removal, PD cytology, PD dilatation, PD stone removal was present in 73%, 50%, 32%, 53%, 44%, & 42% respectively. When compared to GE documentation RAD failed to document the CBD & PD diameter, 27% of BD cytology cases, 50% of biliary dilatation, 68% of BD stone removal, 47% of PD cytology, 55% of PD dilatation & 58% of PD stone removal. Under INTERP of findings frequently occurred in RAD dictated report when compared to GE. CONCLUSION: Many important aspects of the ERCP findings are under documented when interpreting findings using hard copies only. This could be due to lack of adequate film documentation of the procedure. The extent of documentation carries clinical & medicolegal importance. Careful reviews of both real time images & hard film copies are essential to ensure accurate final INTERP.