Drawing Regions Of Interest Research Articles

Limited accuracy of DCE-MRI in identification of pathological complete responders after chemoradiotherapy treatment for rectal cancer.

To examine whether post-chemoradiotherapy (CRT) DCE-MRI can identify rectal cancer patients with pathologic complete response (pCR). From a rectal cancer surgery database 2007-2014, 61 consecutive patients that met the following inclusion criteria were selected for analysis: (1) stage II/III primary rectal adenocarcinoma; (2) received CRT; (3) underwent surgery (4); underwent rectal DCE-MRI on a 1.5-T MRI scanner. Two experienced radiologists, in consensus, drew regions of interest (ROI) on the sagittal DCE-MRI image in the tumour bed. These were exported from ImageJ to in-house Matlab code for modelling using the Tofts model. K trans, K ep and v e values were compared to pathological response. Of the 61 initial patients, 37 had data considered adequate for fitting to obtain perfusion parameters. Among the 13 men and 24 women, median age 53years, there were 8 pCR (22%). K trans could not distinguish patients with pCR. For patients with 90% or greater response, mean K trans and K ep values were statistically significant (p = 0.032 and 0.027, respectively). Using a cutoff value of K trans = 0.25min-1, the AUC was 0.71. K trans could be used to identify patients with 90% or more response to chemoradiotherapy for rectal cancer with an AUC of 0.7. • Chemoradiotherapy for rectal cancer causes decreased blood flow and permeability in the tumour bed. • Lower values of blood flow and permeability correlate with good tumour response. • K trans of 0.25min -1 best identifies patients with ≥90% response with AUC 0.71.

Dual Energy CT- Surrogate Quantitative Marker of Response to Targetted treatment in HCC

Background and Aim: Dual energy CT (DECT)– novel CT imaging technique at two different energies, can be used to discriminate between different materials (e.g., fat, calcium, iodine, and water), which are not allowed by conventional CT. The images reconstructed from these differential data, including iodine concentration maps, may provide diagnostic information beyond that obtainable with conventional CT Aim: To evaluate the supplementary value of dual energy CT to assess response in cirrhotic patients with HCC following targeted therapy. Methods: 20 patients with targeted therapies for dual energy CT (TACE/TARE/RFA) were evaluated. Iodine uptake(IU), derived from the iodine-based material-decomposition image and the iodine concentration ratio on the dual energy CT acquired during early portal venous phase was calculated by drawing regions of interest within the treated lesion, at the edge and within the surrounding liver parenchyma. Quantification of IU (absolute value for total IU (mg) and volume-normalized IU (mg/ml)) was based on semi-automatic tumor volume segmentation compared to the background liver. The decrease compared with baseline was calculated. Results: The mean normalized IU per patient within the treated lesion compared to the cirrhotic liver parenchyma -31%. Total IU per patient, combining both normalized IU and volume, showed the most pronounced decrease. Conclusion: DECT enables objective, easy and fast parameterization of tumor size and contrast medium uptake. DECT provides a quantitative method with which to analyze the treated lesions in the cirrhotic liver. The authors have none to declare.

TEP/TDM à la 18-fluorocholine dans le cancer de prostate : quel protocole d’acquisition ?

ObjectiveTo define an optimal acquisition protocol for 18-fluorocholine (18-FCH) PET/CT in prostate cancer (PCa), due to lack of standard guidelines from the nuclear medicine associations. Materials and methodsTwenty-four PCa patients were included and have had an 18-FCH three phase PET/CT: dynamic pelvic study during the first 10minutes post-tracer injection (PI), static base of skull–mid thigh at 20 and 60minutes PI. A quantitative analysis of tracer activity was performed on target tissue and healthy ones at 20 and 60minutes by drawing regions of interest and measuring the SUVmax. A statistical analysis was performed on the SUVmax values of the lesions obtained at 20 and 60minutes PI in order to find a difference between the results and also between the lesions and healthy tissue. ResultsOur study showed no significant difference in the SUVmax values measured at target tissue between 20 and 60minutes (P=0.98). However, there is a significant difference between target and healthy tissue (Pprostate=0.006 at 20 and 60minutes, Plymph node=0.016 at 20minutes 0.0047 at 60minutes). Our sample group was too small to obtain a statistical difference between healthy bone and target lesion. ConclusionOur study showed no significant differences between the results of 18-FCH PET/CT obtained at 20 and 60minutes PI in PCa. So we propose a pelvic dynamic acquisition during the first 10minutes PI, then an acquisition PET/CT from the cranial vault-mid thigh at 20minutes PI.

Diagnostic contribution of quantitative analysis of salivary scintigraphy in patients with suspected Sjögren's syndrome

AimThe evaluation of the salivary scintigraphy is part of the classification criteria of Sjögren's syndrome (SS). The aim of the study was to determine a method of quantitative evaluation of this technique with easy application and high diagnostic accuracy. Material and methodsA review was carried out on a total of 111 patients with clinical suspicion of SS, referred to our department over the last 4 years (94 women, range 14–82 years). Thirty-minute dynamic studies were performed after injection of 99mTc-pertechnetate, with secretory stimulus at 15min. After drawing regions of interest in both parotids, submandibular glands, and in the background, quantitative parameters were determined. These included the ejection fraction, uptake ratio at 15min, and the percentage uptake (PC). Based on the definitive diagnosis, the subjects were classified into patients with SS, with sicca syndrome, and healthy subjects. ResultsSignificant differences were found between the SS group and healthy subjects in the 3 quantitative parameters for the 4 glands. Significant differences in the PC parameter were observed between the group with sicca syndrome and healthy subjects. ROC analysis showed that the best differentiation parameter for the 3 groups was the PC in both parotid and submandibular glands. ConclusionsThe quantitative analysis of salivary scintigraphy has proved to be a useful method and easy to apply in daily practice to differentiate patients with SS from healthy subjects, with the PC, both in parotid and submandibular glands, being the parameter with highest diagnostic accuracy.

Feasibility Study of a Contrast-Enhanced Multi-Detector CT (64 Channels) Protocol for Papillary Thyroid Carcinoma: The Influence of Different Scan Delays on Tumor Conspicuity.

Recently, a number of studies have advocated the diagnostic benefit of contrast-enhanced computed tomography (CECT) in the current ultrasound (US)-based preoperative evaluation of thyroid cancer. However, no study has been conducted to optimize a CECT protocol focusing on tumor conspicuity using a multi-detector CT scanner. This study aimed at determining the optimal scan delay for increased CT attenuation differences between thyroid cancer and parenchymal background using a biphasic CECT examination. This study retrospectively enrolled 84 patients (M:F = 7:77; Mage = 44.8 ± 10.9 years) with 87 papillary thyroid carcinomas (Msize = 14.1 mm) who consecutively underwent US and CECT examination prior to surgery. In each patient, CT scanning was taken twice-once with a 40-second delay and once with a 70-second delay-using a 64-channel multi-detector scanner. After obtaining the mean attenuation value (MAV) of the thyroid cancer and the ipsilateral parenchyma by drawing regions of interest on the CECT images based on their cytopathologic results and US findings, the parenchyma-cancer differences (PCD) between the early and delayed scans were simply compared using a paired t-test. Then, the mean differences in the MAVs of the thyroid cancer and ipsilateral parenchyma (hereafter abbreviated as Group) between the early and delayed scans (abbreviated as Time) were compared after adjusting for the other factors that significantly affected MAVs, such as concentration of iodinated contrast medium (abbreviated as CCM) and size of thyroid cancer (abbreviated as Size) using a repeated-measures general linear model. Because the ipsilateral parenchyma exhibited significantly higher attenuation on the early scan and further decline on the delayed scan compared with thyroid cancer (p < 0.001), the PCD for thyroid cancer was significantly better with a 40-second scan delay than a 70-second delay (58.8 ± 36.6 Hounsfield units [HU] vs. 40.4 ± 25.6 HU; p < 0.001). Similar results were obtained from the repeated-measures general linear model that considered the effects of CCM, Size, Group, and Time, and the interaction of Group and Time. Based on this CECT study that adjusted for the effects of CCM and size on MAV, early scans (e.g., 40-second scan delay) are helpful for improving the tumor conspicuity of thyroid cancer on CECT images.

Abnormal functional connectivity density in first-episode, drug-naive adult patients with major depressive disorder

Previous studies have found evidence of brain functional connectivity (FC) changes with pre-selected region-of-interest (ROI) method in major depressive disorder (MDD). However, these studies could not completely exclude personal inequality when drawing ROIs manually and did not measure the total number of FC for each voxel. Here, we firstly applied functional connectivity density (FCD) mapping, a voxel-based analysis to locate the hubs with amount changes of FC between 22 first-episode, drug-naive adult MDD patients and 22 healthy control (HC) subjects. Both short-range (local) FCD and long-range (distal) FCD were measured. The relationships of FCD changes with Hamilton Depression Rating Scale (HAMD) scores and illness duration were also explored. Compared with the HC group, MDD patients showed significantly decreased short-range FCD in the left superior temporal gyrus (STG), the right orbital frontal cortex (OFC) and bilateral precuneus, while significantly decreased long-range FCD was found in bilateral middle occipital gyrus (MOG), superior occipital gyrus (SOG) and right calcarine. These results firstly demonstrated both local and distal alterations of connection amount at voxel level, and highlighted that the OFC, the precuneus, the STG and the visual cortex were important brain network hubs for first-episode, drug-naive adult MDD patients. Our findings were complementary for previous structural and functional studies in MDD patients, and provided new evidence of the dysfunction of connection hubs in the pathophysiology of MDD at voxel level.

An algorithm for automated ROI definition in water or epoxy-filled NEMA NU-2 image quality phantoms.

Drawing regions of interest (ROIs) in positron emission tomography/computed tomography (PET/CT) scans of the National Electrical Manufacturers Association (NEMA) NU‐2 Image Quality (IQ) phantom is a time‐consuming process that allows for interuser variability in the measurements. In order to reduce operator effort and allow batch processing of IQ phantom images, we propose a fast, robust, automated algorithm for performing IQ phantom sphere localization and analysis. The algorithm is easily altered to accommodate different configurations of the IQ phantom. The proposed algorithm uses information from both the PET and CT image volumes in order to overcome the challenges of detecting the smallest spheres in the PET volume. This algorithm has been released as an open‐source plug‐in to the Osirix medical image viewing software package. We test the algorithm under various noise conditions, positions within the scanner, air bubbles in the phantom spheres, and scanner misalignment conditions. The proposed algorithm shows runtimes between 3 and 4 min and has proven to be robust under all tested conditions, with expected sphere localization deviations of less than 0.2 mm and variations of PET ROI mean and maximum values on the order of 0.5% and 2%, respectively, over multiple PET acquisitions. We conclude that the proposed algorithm is stable when challenged with a variety of physical and imaging anomalies, and that the algorithm can be a valuable tool for those who use the NEMA NU‐2 IQ phantom for PET/CT scanner acceptance testing and QA/QC.PACS number: 87.57.C‐

Comparing SUV values of images at PET-CT console and the RT planning console using identical dataset of a study phantom.

The use of positron emission tomography (PET) for radiotherapy planning purposes has become increasingly important in the last few years.In the current study, we compared the SUV values of images at the PET CT console to the SUV values obtained at the RT planning workstation. The PET-CT cylindrical body phantom was filled with a uniform 18F solution of 5.3. ± 0.27 kBq/mL radioactivity concentration. PET-CT scans were performed on a16 slice Time of Flight system. On a single day, the three consecutive scans were done at three time points 15 minutes apart to generate time points image data sets titled T1, T2, and T3. SUV calculations were performed by drawing region of interest. (ROI) encompassing the entire hot spot on each slice on the PET-CT console and the iPlan workstation. Minimum SUV, Maximum SUV and the Mean SUV were recorded. Statistical analysis was done using the SPSS software. (SPSS Inc.) (Version 18). The absolute difference in average max SUV values i.e. Max (PET-CT) - Max (iPlan) for the time points T1, T2 and T3 were -0.168 (SD 0.175), -0.172 (SD 0.172) and -0.178 (SD 0.169). The difference in the minimum SUV values were -0.513 (SD 0.428), -0.311 (SD 0.358) and -0.303 (SD 0.322), respectively. Finally, the difference in the mean SUV values were -0.107 (SD 0.040), -0.096 (SD 0.067) and -0.072 (SD 0.044), respectively. Our study found out that the average difference in the two systems for maximum SUV values was < 0.2 absolute units.Our study suggests good reproducibility of SUV between the two systems. The relevance of these findings would be of seminal importance in current and future SUV-based PET-CT-based contouring in treatment planning systems.

Reliability, repeatability, and reproducibility of pulmonary transit time assessment by contrast enhanced echocardiography.

BackgroundThe aim of this study is to investigate the inter and intra-rater reliability, repeatability, and reproducibility of pulmonary transit time (PTT) measurement in patients using contrast enhanced ultrasound (CEUS), as an indirect measure of preload and left ventricular function.MethodsMean transit times (MTT) were measured by drawing a region of interest (ROI) in right and left cardiac ventricle in the CEUS loops. Acoustic intensity dilution curves were obtained from the ROIs. MTTs were calculated by applying model-based fitting on the dilution curves. PTT was calculated as the difference of the MTTs. Eight raters with different levels of experience measured the PTT (time moment 1) and repeated the measurement within a week (time moment 2). Reliability and agreement were assessed using intra-class correlations (ICC) and Bland-Altman analysis. Repeatability was tested by estimating the variance of means (ANOVA) of three injections in each patient at different doses. Reproducibility was tested by the ICC of the two time moments.ResultsFifteen patients with heart failure were included. The mean PTT was 11.8 ± 3.1 s at time moment 1 and 11.7 ± 2.9 s at time moment 2. The inter-rater reliability for PTT was excellent (ICC = 0.94). The intra-rater reliability per rater was between 0.81–0.99. Bland-Altman analysis revealed a bias of 0.10 s within the rater groups. Reproducibility for PTT showed an ICC = 0.94 between the two time moments. ANOVA showed no significant difference between the means of the three different doses F = 0.048 (P = 0.95). The mean and standard deviation for PTT estimates at three different doses was 11.6 ± 3.3 s.ConclusionsPTT estimation using CEUS shows a high inter- and intra-rater reliability, repeatability at three different doses, and reproducibility by ROI drawing. This makes the minimally invasive PTT measurement using contrast echocardiography ready for clinical evaluation in patients with heart failure and for preload estimation.Electronic supplementary materialThe online version of this article (doi:10.1186/s12947-015-0044-1) contains supplementary material, which is available to authorized users.

Paradoxical centrally increased diffusivity in perinatal arterial ischemic stroke.

Restricted diffusion on acute MRI is the diagnostic standard for perinatal arterial ischemic stroke. In a subset of children with perinatal arterial ischemic stroke, primarily those with large infarct volumes, we noted a core of centrally increased diffusivity with a periphery of restricted diffusion. Given the paradoxical diffusion-weighted imaging (DWI) appearance observed in some children with perinatal arterial ischemic stroke, we sought to determine its significance and hypothesized that: (1) centrally increased diffusivity is associated with larger infarcts in perinatal arterial ischemic stroke and (2) this tissue is irreversibly injured (infarcted). We reviewed all perinatal arterial ischemic stroke cases in a prospective cohort study from Aug. 1, 2000, to Jan. 1, 2012. Infarct volumes were measured by drawing regions of interest around the periphery of the area of restricted diffusion on DWI. The Mann-Whitney U test was used to compare means between groups. Of 25 eligible cases, centrally increased diffusivity was seen in 4 (16%). Cases with centrally increased diffusivity had larger average infarct volumes (mean 117,182 mm(3) vs. 36,995 mm(3); P = 0.008), higher average apparent diffusion coefficient (ADC) values in the infarct core (1,679 × 10(-6) mm(2)/s vs. 611 × 10(-6) mm(2)/s, P < 0.0001), and higher ADC ratio (1.2 vs. 0.5, P < 0.0001). At last clinical follow-up, children with perinatal arterial ischemic stroke and centrally increased diffusivity were more often treated for ongoing seizures (75% vs. 0%; P < 0.001) than those without. Centrally increased diffusivity was associated with larger stroke volume and the involved tissue was confirmed to be infarcted on follow-up imaging. Radiologists should be aware of this unusual appearance of perinatal arterial ischemic stroke in order to avoid underestimating infarct volume or making an incorrect early diagnosis.

208 Arterial Inflammation and Calcification in Patients with Lower Limb Atherosclerosis using PET/CT Analysis: A Proof-of-Principle Study

<h3>Introduction</h3> Lower limb peripheral arterial disease (PAD) is common. Atherosclerotic development is linked with inflammatory and calcific processes occurring at the vessel wall, having been evaluated in the coronary and carotid circulation using PET/CT analysis with the 18F FDG (inflammation) and 18F NaF (calcification) tracers. <h3>Methods</h3> 8 patients (16 legs; 5 men, median age 74.5 years; IQR (69.5–77.5)) with a diagnosis of intermittent claudication were prospectively recruited to the study. PET/CT analysis was undertaken in each patient using both tracers. The lower limb arterial tree was examined from the aortic bifurcation to the ankle. The degree of arterial calcification (AC) was measured using a modified Agatston score. Arterial 18F-NaF and 18F-FDG uptake was determined using standard protocols and measured by drawing regions of interest and normalised to tracer levels in the common femoral vein to obtain the arterial target-to-background ratio (TBR). Correlation between tracer uptake and AC was determined using Pearson’s correlation. <h3>Results</h3> The overall whole limb median (IQR) TBR levels for 18F NaF was 1.30 (0.98–1.74) and for 18F FDG was 1.42 (1.11–1.75). The median limb AC score was 1954.5 (1198–3216). A positive correlation was observed when arterial 18F FDG uptake was correlated with 18F NaF uptake (p = 0.000, r = 0.611) and AC score (p = 0.009, r = 0.654). An inverse correlation was found when correlating 18F NaF tracer uptake with AC score (p = 0.004, r=–0.765). <h3>Conclusion</h3> Lower limb disease progression will lead to increased atherosclerotic burden with a potential risk of amputation. This study is the first to determine the inter-relationship between inflammation and calcification within the lower limb arterial tree. Further studies are required to look at longer-term sequelae of atherosclerotic progression/development.

Fat Fraction Quantification of Lumbar Paravertebral Muscle in Magnetic Resonance Imaging using Six Echoes Dixon Technique

Introduction Increasing studies on the muscles volume in the lumbar spine of low back pain patients is available in the literature. So far, these studies were focused only on the volume of the muscle, but the quality of muscle is more important, and the quality of muscle can be evaluated with the fat fraction ratio. To measure fat fraction of muscle, currently, 2, 3 points echo Dixon techniques were used, but its accuracy is a problem. Therefore, we use the first 6 points echo Dixon and to compare accuracy of 2 echo Dixon, 3 point Dixon imaging with that from MR spectroscopy as reference. Patients and Methods A total of 69 patients (39 women and 22 men; 54.3 ± 19.1) underwent MRI at a 1.5 T scanner. In addition, using T2-corrected Dixon sequence with 2, 3, and 6 echoes were obtained at the L4–L5 levels for fat-signal fraction. Fat-signal fraction from MR spectroscopy was also obtained at lumbar muscles of L4–L5 levels. Fat-signal fractions were measured directly by drawing region of interest at the automatically obtained fat-signal fraction mapping images from the three sequences. ROIs were drawn at the three consecutive slices of mapping images at the same location of the spectroscopic voxel by two musculoskeletal radiologists in consensus and the average values were obtained. The Student t test and Bland–Altman plots were used to quantify agreement between the values obtained from mapping images and those from spectroscopy. The p values &lt; 0.05 were considered to be statistically significant. Results A total of 120 spectroscopic measurements were performed bilaterally. Mean spectroscopic fat-signal fraction percentage was 14.0 ± 11.8 (range, 2.9–63.6). Correlation between spectroscopic and all imaging-based fat-signal fractions was statistically significant ( R2 = 0.92 [2 echo], 0.91 [3 echo], and 0.96 [6 echo], all p &lt; 0.001). Fat-signal fractions obtained from 6-echo T2-corrected Dixon sequence best correlated among all imaging-based fat-signal fractions with statistical significance ( p &lt; 0.001). Conclusion T2-corrected 6-echo Dixon sequence best correlates with spectroscopic fat-signal fractions as compared with 2 echo and 3 echo sequences, thus being expected to be used as an accurate quantification tool for measurement of muscle fat quantification in lumbar spine MR imaging.

Characteristics of Dynamic Magnetic Resonance Image Enhancement in Prolactinomas Resistant to Dopamine Agonist Therapy

ObjectiveThe objective of this study was to determine whether dynamic magnetic resonance imaging (dMRI) enhancement parameters could predict dopamine agonist (DA) resistance in prolactinomas.MethodsWe retrospectively identified patients with prolactinomas who...

Quantification of radionuclide uptake levels for primary bone tumors

The purpose of the study is to quantify the level of uptake of administered radionuclide in primary bone tumors for patients undergoing bone scintigraphy. Retrospective study on 48 patient's scintigrams to quantify the uptake levels of administered radiopharmaceuticals was performed in a nuclear medicine unit in Ghana. Patients were administered with activity ranging between 0.555 and 1.110 MBq (15–30 mCi), and scanned on Siemens e.cam SPECT system. Analyses on scintigrams were performed with Image J software by drawing regions of interest (ROIs) over identified hot spots (pathologic sites). Nine skeletal parts namely cranium, neck, shoulder, sacrum, sternum, vertebra, femur, ribcage, and knee were considered in the study, which involved 96 identified primary tumors. Radionuclide uptakes were quantified in terms of the estimated counts of activity per patient for identified tumor sites. Average normalized counts of activity (nGMC) per patient ranged from 5.2759 ± 0.6590 cts/mm2/MBq in the case of cranium tumors to 72.7569 ± 17.8786 cts/mm2/MBq in the case of ribcage tumors. The differences in uptake levels could be attributed to different mechanisms of Tc-99m MDP uptake in different types of bones, which is directly related to blood flow and degree of osteoblastic activity. The overall normalized count of activity for the 96 identified tumors was estimated to be 23.0350 ± 19.5424 cts/mm2/MBq. The study revealed highest uptake of activity in ribcage and least uptake in cranium. Quantification of radionuclide uptakes in tumors is important and recommended in assessing patient's response to therapy, doses to critical organs and in diagnosing tumors.

Abstract 1885: Quantitative Textural Analysis (QTA) in CT imaging: Identifying markers for genetic instability and overall survival in cohort of previously treated metastatic pancreatic cancer (mPC)

Abstract PURPOSE. To explore the use of helical CT-derived Quantitative Textural Analysis (QTA) parameters in identifying elevated rates of intrachromosomal copy number aberrations in mPC and secondarily in revealing post-treatment QTA prognostic markers. MATERIALS AND METHODS. Metastatic tumor sites were biopsied and molecularly profiled in a cohort patients with mPC (n=35). 85% of the cohort had 1-3 previous treatment regimens, and the remaining 15% had 4-6. Intrachromosal copy number were assessed by CGH in tumor specimens, and patients were treated with commercially available cytotoxic regimens based on these individual molecular profiling results1. Patients with available pre-biopsy transverse abdominal portal-venous phase CT scans were obtained for retrospective analysis (n=17). Analysis of pre-biopsy pancreas imaging was performed by drawing regions of interest around the primary pancreas adenocarcinoma (n=15) and the normal pancreas tissue when available (n=12). Two patients did not have any quantifiable imaging due to surgery or local structural obfuscation and were not included in our cohort. There were 9 males and 6 females all with stage IV cancer from 34 - 71 years old (median 59). QTA parameters were derived using the TexRAD platform at texture filtering densities of medium (3 pixels) and coarse (5 pixels). There values were compared to intrachromosomal copy number aberrations per tumor and overall survival post-treatment using a Spearman's rank correlation coefficient. RESULTS. Intrachromosomal copy number aberrations (median: 14; range: 5 - 52) were negatively correlated with the kurtosis value of the primary tumor mass (median: -0.146; range: -0.810 - 0.633) using medium texture filtering (p = 0.034, n = 15). Secondary analysis of the normal pancreas with coarse texture filtering yielded a correlation between reduced overall survival time post-treatment and increasing entropy (p = 0.0014, n = 12). Using entropy as a cutoff value (median: 4.165; range 2.686 - 4.891), median overall survival was greater in the entropy &amp;lt; 4.165 group versus the entropy &amp;gt; 4.165 group (6.1 v 2.0 months, respectively; hazards ratio [HR] = 11.5; 95% CI 1.36 - 97.4; p = 0.025, n = 12). Median survival for the entire cohort was 120 days and ranged from 1 day to 372 days post-treatment. CONCLUSION. This exploratory study with admittedly limited sample size raises interesting questions about the use of QTA parameters as diagnostic tools and/or biopsy adjuncts in assessing pancreatic adenocarcinoma susceptibility to commercially available cytotoxics. Secondarily, entropy, a potential marker of heterogeneity and inflammation in the normal pancreas, represents an intriguing possibility for gauging prognosis in mPC. (Clinical trial supported by a grant from the SU2C/AACR-pancreatic dream team) REFERENCES. 1. Ramanathan RK et al AACR Annual Meeting. LB-221. 2012. Citation Format: David H. Campbell, Michael Barrett, Ramesh K. Ramanathan, Daniel D. Von Hoff, Ronald Korn. Quantitative Textural Analysis (QTA) in CT imaging: Identifying markers for genetic instability and overall survival in cohort of previously treated metastatic pancreatic cancer (mPC). [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1885. doi:10.1158/1538-7445.AM2014-1885

Quantitative chemical-shift MR imaging cutoff value: Benign versus malignant vertebral compression – Initial experience

PurposeTo evaluate the diagnostic accuracy of in-phase/opposed-phase quantitative chemical shift magnetic resonance (MR) imaging of the spine and to determine the cutoff value that enables differentiation of malignant from benign compression fractures, in patients with known primary malignancy. Patients and methodsProspective assessment of thirty-two patients with known primary malignancy who presented with vertebral compression fractures, MR imaging of the spine at 1.5Tesla with standard conventional MR sequences and additional chemical shift (in-phase/opposed-phase) imaging was done. Quantitative image analysis by drawing regions of interest (ROI) on the abnormal marrow of compressed (study group) and adjacent normal vertebra (control group) was also performed in each patient. The signal intensity ratio (SIR) of the marrow was determined by dividing the mean signal intensity on the opposed-phase to the mean signal intensity on the in-phase images and statistical analysis was performed. ResultsMean SIR of benign vertebral compression [0.73±0.07 (range 0.12–1.2)] was significantly lower than malignant SIR values [1.72±0.14 (range 0.8–2.96)] (p<0.0001; area under the ROC curve, 0.97). The optimal SIR cutoff value for separating benign and malignant vertebral compression was found to be 0.91 with a calculated sensitivity of 93%, specificity of 82% and accuracy of 88%. ConclusionQuantitative chemical shift MR imaging could be a valuable addition to standard MR imaging techniques and represent a rapid problem solving tool in differentiating benign from malignant vertebral compression, especially in patients with known primary malignancies.

MP7-03 IMAGING MICROSTRUCTURAL PROPERTIES OF THE KIDNEYS USING DIFFUSION TENSOR- MRI

You have accessJournal of UrologyImaging/Radiology II1 Apr 2014MP7-03 IMAGING MICROSTRUCTURAL PROPERTIES OF THE KIDNEYS USING DIFFUSION TENSOR- MRI Sophie van Baalen, Martijn Froeling, Alexander Leemans, Bennie ten Haken, Aart Klijn, Tom de Jong, and Pieter Dik Sophie van BaalenSophie van Baalen More articles by this author , Martijn FroelingMartijn Froeling More articles by this author , Alexander LeemansAlexander Leemans More articles by this author , Bennie ten HakenBennie ten Haken More articles by this author , Aart KlijnAart Klijn More articles by this author , Tom de JongTom de Jong More articles by this author , and Pieter DikPieter Dik More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2014.02.326AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Acute Pyelonephritis (APN) is a common disease in children: about 2.7% of girls and 1% of boys have an APN by the age of 7. APN can result in irreversible damage to the renal parenchyma, affecting the growth and development of the kidney and possibly leading to renal insufficiency, protein loss and hypertension. All children receive a DMSA scintigraphy 6 months after an APN episode to assess the occurrence and extent of renal scars. The radiation dose of 1 mSv/examination imposes a long-term risk in young children. Replacing the DMSA scan with an MRI scan for children with APN would eliminate the risks associated with using ionizing radiation. A promising MRI technique is Diffusion Tensor Imaging (DTI). DTI enables measuring the direction and extend of water diffusion in renal tissue, without using contrast agents. In this study, MRI-DTI was used for kidney imaging to evaluate whether this technology can visualize the microstructural architecture of healthy kidney tissues. METHODS Ten healthy volunteers were scanned on a 3 Tesla MRI scanner. The resulting images were processed to enable Diffusion-Tensor based tractography, visualizing the 3D tissue structure of the kidney. The diffusion parameters Fractional Anisotropy (FA) and Mean Diffusivity (MD) were measured by drawing regions of interest in the medulla and cortex. This study was approved by the ethical committee of our institution. RESULTS The radial orientation of the medullar tissue was visualized and the pyelum contour was segmented. Tracts originate in the cortex and convolute in multiple papillae, at the edge of the pyelum contour, reflecting the microstructure of medulla, consisting of radially oriented straight tubules and vascular network. Differentiation of cortical and medullary tissue based on FA and MD measurement was possible. One volunteer happened to have a dysplastic kidney with evident disturbed microstructural properties on the MRI-DTI tractography image. CONCLUSIONS MRI-DTI is able to visualize the microstructural architecture, especially the renal pyramids, the papillae and major and minor calyxes of the kidney. We are sure that in near future we will be able to visualize alterations in the microstructure e.g. scar tissue formation using this method. © 2014FiguresReferencesRelatedDetails Volume 191Issue 4SApril 2014Page: e65-e66 Advertisement Copyright & Permissions© 2014MetricsAuthor Information Sophie van Baalen More articles by this author Martijn Froeling More articles by this author Alexander Leemans More articles by this author Bennie ten Haken More articles by this author Aart Klijn More articles by this author Tom de Jong More articles by this author Pieter Dik More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

Registration of dynamic contrast‐enhanced MRI of the common carotid artery using a fixed‐frame template‐based squared‐difference method

This study examines template-based squared-difference registration for motion correction in dynamic contrast-enhanced (DCE) MRI studies of the carotid artery wall and compares the results of fixed-frame template-based registration with a previously proposed consecutive-frame registration method. Ten T1-weighted black-blood, turbo spin-echo DCE-MRI studies of the carotid artery wall were used to test template-based squared-difference registration. An intermediate image from each series was selected as the fixed-frame template for registration. Squared-difference minimization was used to align each image and template. Time-intensity curves generated from data aligned with template-based squared-difference registration were compared with gold standard curves created by drawing regions of interest on each image in the series. The results were also compared with unregistered data and data after consecutive-frame squared-difference registration. An analysis of variance test of root mean-square error values between gold standard curve and curves from unregistered data and data registered with consecutive-frame and fixed-frame template-based methods was significant (P < 0.005) with template-based squared-difference registration producing curves that most closely matched the gold standard. A fixed-frame template-based squared-difference registration method was proposed and validated for alignment of DCE-MRI of carotid arteries.

Changes in human placental oxygenation during maternal hyperoxia estimated by blood oxygen level‐dependent magnetic resonance imaging (BOLD MRI)

To investigate changes in human placental oxygenation during maternal hyperoxia using non-invasive blood oxygen level-dependent (BOLD) magnetic resonance imaging (MRI). Eight healthy pregnant women with uncomplicated singleton pregnancies at gestational weeks 28-36 were examined with BOLD MRI, over two consecutive 5-min periods of different oxygenation: first normoxia (21% O2 ) and then hyperoxia (12 L O2 /min), achieved by controlling the maternal oxygen supply with a non-rebreather facial mask. Selecting three slices showing cross-sections of the central part of the placenta, we investigated total placental oxygenation by drawing regions of interest (ROIs) covering the entire placenta, and regional placental oxygenation by drawing smaller ROIs in the darker and brighter areas of the placenta. For each ROI, the difference in BOLD signal between the two episodes was determined and the percentage increase in BOLD signal during hyperoxia (ΔBOLD) was calculated. In the BOLD image, the normoxic placenta appeared heterogeneous, with darker areas located to the fetal side and brighter areas to the maternal side. During hyperoxia, the placenta became brighter and the structure more homogeneous, and the BOLD signal of the total placenta increased (ΔBOLDtot , 15.2 ± 3.2% (mean ± SD), P < 0.0001). The increase was seen predominantly in the dark areas in the fetal part of the placenta (ΔBOLDfet , 32.1 ± 9.3%) compared with in the bright areas in the maternal part of the placenta (ΔBOLDmat , 5.4 ± 3.5%). During hyperoxia, placental oxygenation was increased predominantly in the darker placental areas, which, given their anatomical location, represent the fetal circulation of the placenta. To our knowledge, this is the first study to successfully visualize changes in placental oxygenation using BOLD MRI.

Impact of anesthetics on 3'-[18F]fluoro-3'-deoxythymidine ([18F]FLT) uptake in animal models of cancer and inflammation.

The aim of this study was to evaluate the impact of different anesthetics on 3'-[18F]fluoro-3'-deoxythymidine ([18F]FLT) uptake in carcinomas and arthritic ankles. To determine the amount of [18F]FLT uptake in subcutaneous CT26 colon carcinomas or arthritic ankles, spontaneously room air/medical air-breathing mice were anesthetized with isoflurane, a combination of medetomidine/midazolam, or ketamine/xylazine. Mice were kept conscious or anesthetized during [18F]FLT uptake before the 10-minute static positron emission tomographic (PET) investigations. [18F]FLT uptake in CT26 colon carcinomas and arthritic ankles was calculated by drawing regions of interest. We detected a significantly reduced (4.4 ± 0.9 %ID/cm3) [18F]FLT uptake in the carcinomas of ketamine/xylazine-anesthetized mice compared to the [18F]FLT-uptake in carcinomas of medetomidine/midazolam- (7.0 ± 1.5 %ID/cm3) or isoflurane-anesthetized mice (6.4 ± 1.5 %ID/cm3), whereas no significant differences were observed in arthritic ankles regardless of whether mice were anesthetized or conscious during tracer uptake. The time-activity curves of carcinomas and arthritic ankles yielded diverse [18F]FLT accumulation related to the used anesthetics. [18F]FLT uptake dynamics are different in arthritic ankles and carcinoma, and the magnitude and pharmacokinetics of [18F]FLT uptake are sensitive to anesthetics. Thus, for preclinical in vivo [18F]FLT PET studies in experimental tumor or inflammation models, we recommend the use of isoflurane anesthesia as it yields a stable tracer uptake and is easy to handle.