Magnetic Resonance Imaging MRI Research Articles

Appearances of von Meyenburg Complex on Cross Sectional Imaging

The von Meyenburg complex (VMC) is an uncommon congenital malformation and is characterized by benign bile duct hamartomas. These are usually discovered incidentally and may represent a diagnostic dilemma when liver metastases are suspected. MRI of VMC shows distinct imaging characteristics, but reporting of lesional contrast enhancement has been inconsistent, whilst microbubble contrast enhanced ultrasound provides ‘real-time’ evaluation of soft tissue vascularity. Given the diagnostic uncertainty over imaging in VMC, biopsy is often recommended as the definitive diagnosis. We report a biopsy proven case of VMC on a background of primary colonic malignancy investigated with ultrasound, contrast enhanced ultrasound, computed tomography CT, and magnetic resonance imaging MRI, and review the key imaging features.

Functionally-detected cognitive impairment in high school football players without clinically-diagnosed concussion.

Head trauma and concussion in football players have recently received considerable media attention. Postmortem evidence suggests that accrual of damage to the brain may occur with repeated blows to the head, even when the individual blows fail to produce clinical symptoms. There is an urgent need for improved detection and characterization of head trauma to reduce future injury risk and promote development of new therapies. In this study we examined neurological performance and health in the presence of head collision events in high school football players, using longitudinal measures of collision events (the HIT(™) System), neurocognitive testing (ImPACT(™)), and functional magnetic resonance imaging MRI (fMRI). Longitudinal assessment (including baseline) was conducted in 11 young men (ages 15-19 years) participating on the varsity and junior varsity football teams at a single high school. We expected and observed subjects in two previously described categories: (1) no clinically-diagnosed concussion and no changes in neurological behavior, and (2) clinically-diagnosed concussion with changes in neurological behavior. Additionally, we observed players in a previously undiscovered third category, who exhibited no clinically-observed symptoms associated with concussion, but who demonstrated measurable neurocognitive (primarily visual working memory) and neurophysiological (altered activation in the dorsolateral prefrontal cortex [DLPFC]) impairments. This new category was associated with significantly higher numbers of head collision events to the top-front of the head, directly above the DLPFC. The discovery of this new category suggests that more players are suffering neurological injury than are currently being detected using traditional concussion-assessment tools. These individuals are unlikely to undergo clinical evaluation, and thus may continue to participate in football-related activities, even when changes in brain physiology (and potential brain damage) are present, which will increase the risk of future neurological injury.

Ameliyathane dışı anestezi deneyimlerimiz

Anesthesia experiences outside of the operating room Introduction And Aim: Thanks to technological developments, invasive and non-invasive diagnostic and therapeutic procedures have been done at the outside of the operating room. In this manner, to provide anesthesia at the outside of the operating room, anesthesia teams have been found. In this study, we aimed to report our anesthesia teams’ experiences. Materials And Methods: We reviewed the procedures that was experienced at outside the operating room from October 2010 to April 2012 retrospectively. 3583 Patients who required anesthesia at the outside of the operating room included the study, and their sexes, ages, ASA status, procedures, and anesthesia complications were recorded. Results: Patients’ sex ratio male/female 1671/1912; ranged in age from 20 day to 91 years; with the mean age 48,52±28,4. ASA status were, ASA I 1958, ASA II 1296, ASA III 318, ASA IV 11. Anesthesia procedures were for 1837 colonoscopy, 536 gastroscopy, 131 ERCP endoscopic retrograde cholangiopancreatography, 811 MRI magnetic resonance imaging, 62 CTI computerized tomography imaging, 234 ECT electroconvulsive therapy, 106 RT radiotherapy, 40 angiographic aneurysm embolization, 9 angiographic venous sampling, 43 carotis stent, and 63 other radiologic interventions. For sedation; 1960 Patient received propofol + alfentanil, 740 only propofol, 544 propofol + fentanyl, 115 ketofol, 65 midazolam+ketamin 83 dexmedetomidine. For electroconvulsive therapies, 90 patient received etomidate + succinyl choline, 144 propofol + succinyl choline. 40 patient received general anesthesia for embolisation procedures. There are no major complication occured except one patient experienced intracranial hemorrhage during colonoscopy. In minor complications; 12 patient experienced respiratory depression, 41 bradycardia, 144 oxygen desaturaion, 191 prolonged recovery from anesthesia, 8 vomiting. Conclusion: Anesthesia procedures at the outside of the operating room are frequently used in all medical interventions and at all ages. Remote locations from operating room, inadequate equipment and monitors,not enough space in the working environment, providing anesthesia outside the operating room is challenging and requires expertise and skill. The secret of success in anesthesia in remote locations is the skilled anesthesiologist with the appropriate equipment and drugs, along with adequate backup facilities. Anesthesia procedures at the outside of the operating room are guarding the patients safety and welfare, minimising physical discomfort and pain, providing physicians’ comfort.

Low‐molecular contrast agent dynamic contrast‐enhanced (DCE)‐MRI and diffusion‐weighted (DW)‐MRI in early assessment of bevacizumab treatment in breast cancer xenografts

To investigate the effect of bevacizumab treatment on vascular architecture and function in two xenograft models with different angiogenic properties using diffusion-weighted magnetic resonance imaging (DW-MRI) and dynamic contrast-enhanced MRI (DCE-MRI). Mice carrying basal-like (MAS98.12) or luminal-like (MAS98.06) orthotopic breast cancer xenografts were treated with bevacizumab (5 mg/kg), doxorubicin (8 mg/kg), or both drugs in combination. DW-MRI and DCE-MRI were performed before and 3 days after treatment using a Bruker 7T preclinical scanner. Mean microvessel density (MVD) and proliferating microvessel density (pMVD) in the tumors were determined for evaluation of vascular response to bevacizumab treatment. No changes in DCE-MRI or DW-MRI parameters were observed in untreated controls during the experiment period. DW-MRI showed increased apparent diffusion coefficient (ADC) values in all treatment groups in both basal-like and luminal-like xenografts. DCE-MRI showed increased contrast agent uptake, particularly in central regions of the tumors, after bevacizumab/combination treatment in both xenograft models. This was accompanied by decreased MVD and pMVD in basal-like xenografts. Doxorubicin treatment had no effect on DCE-MRI parameters in any of the xenograft models. Both DW-MRI and DCE-MRI demonstrated an early response to bevacizumab treatment in the xenograft tumors. Increased contrast agent uptake and reduced MVD/pMVD is consistent with a normalization of vascular function.

Evaluation and Treatment of Inherited Pheochromocytoma in Pregnancy

ABSTRACT Pheochromocytomas represent a rare, but potentially devastating, cause of hypertension among pregnant patients. Inherited predisposition to these tumors requires vigilant screening, especially in women of child-bearing age. We present an illustrative case of a multiple endocrine neoplasia type 2A patient who was successfully surgically treated for a pheochromocytoma during pregnancy. A review of the existing, English-language literature and screening guidelines was undertaken. Pheochromocytomas presenting during pregnancy, can be safely and effectively treated with laparoscopic surgery, allowing the maintenance of a normal pregnancy. Screening of patients with inherited endocrinopathies that predispose to adrenal medullary tumors must be adapted to maximize the opportunity to detect a pheochromocytoma in the pregravid state. More frequent testing and a lower threshold for biochemical or radiologic investigation are suggested for women in their reproductive years. Abbreviation: MEN—multiple endocrine neoplasia; RET—rearranged during transfection; MRI—magnetic resonance imaging. How to cite this article Thompson AE, James BC, Saunders BD. Evaluation and Treatment of Inherited Pheochromocytoma in Pregnancy. World J Endoc Surg 2013;5(3):82-84.

Virtopsy- A Moral Boon In Forensics

Jeelani S, John Baliah ABSTRACT: Death is an inevitable part of life and at few occasions scientific examination of bodies after death becomes mandatory. The contribution of Forensic science in achieving this is noteworthy. Forensic pathology is a discipline of Forensic science which deals with pathologic and physiologic changes of a body before and after death wherein autopsy plays a significant role. Conventional Autopsy involves Invasive body opening – the traditional means of postmortem investigation in Humans. Contrary to it is Virtopsy, a minimally invasive emerging technology in the field of Forensic medicine which incorporates Imaging technology that relies on certain fundamental pillars which include Three dimensional surface scanning 3D/CAD photogrammetry , MSCTmulti slice computed tomography, MRImagnetic resonance imaging and Magnetic resonance imaging spectroscopy. Thus serving as a moral boon in the field of forensics is Virtopsy which provides a platform wherein radiologists and forensic clinicians reflect an ethical face in forensic examination after death.

Integration of structural and functional magnetic resonance imaging improves mild cognitive impairment detection

The identification of mild cognitive impairments (MCI) via either structural magnetic resonance imaging (sMRI) or functional MRI (fMRI) has great potential due to the non-invasiveness of the techniques. Furthermore, these techniques allow longitudinal follow-ups of single subjects via repeated measurements. sMRI- or fMRI-based biomarkers have been adopted separately to diagnose MCI; however, there has not been a systematic effort to integrate sMRI- and fMRI-based features to increase MCI detection accuracy. This study investigated whether the detection of MCI can be improved via the integration of biomarkers identified from both sMRI and fMRI modalities. Regional volume sizes and neuronal activity levels of brains from MCI subjects were compared with those from healthy controls and used to identify biomarkers from sMRI and fMRI data, respectively. In the subsequent classification phase, MCI was automatically detected using a support vector machine algorithm that employed the identified sMRI- and fMRI-based biomarkers as an input feature vector. The results indicate that the fMRI-based biomarkers provided more information for detecting MCI than the sMRI-based biomarkers. Moreover, the integrated feature sets using the sMRI- and fMRI-based biomarkers consistently showed greater detection accuracy than the feature sets based only on the fMRI-based biomarkers. The results demonstrate that integration of sMRI and fMRI modalities can provide supplemental information to improve the diagnosis of MCI relative to either the sMRI or fMRI modalities alone.

Free-breathing dynamic contrast-enhanced MRI of the abdomen and chest using a radial gradient echo sequence with K-space weighted image contrast (KWIC)

To evaluate the feasibility of free-breathing, dynamic contrast-enhanced (DCE) MRI of the abdomen and thorax using the radial-gradient-echo sequence with k-space weighted image contrast (KWIC) reconstruction. Institutional review board approval was obtained. Fourteen patients underwent free-breathing radial DCE-MRI. Radial MRI yielded full-frame images by gridding all k-space data and time-resolved subframe images by using KWIC reconstruction technique. Using subframe KWIC images, voxel-wise perfusion maps were created. For comparison, the breath-hold conventional Cartesian 3D-gradient-echo sequence (VIBE) was also performed during the equilibrium phase. The image qualities of radial and conventional VIBE images were compared quantitatively and qualitatively. Radial DCE-MRI provided high spatial resolution (1.4 × 1.4 mm) and temporal resolution (4.1 s for subframe images) allowing voxel-wise perfusion mapping with negligible motion or streaking artefacts. There were no significant differences in SNR between full-frame radial images and conventional VIBE images (79.08 vs 74.80, P > 0.05). Overall image quality score of full-frame radial images was slightly lower than that of conventional VIBE images (3.88 ± 0.59 vs. 4.31 ± 0.97, P < 0.05), but provided clinically useful images. The free-breathing radial DCE-MRI can provide high spatial and temporal resolution while maintaining reasonably high image quality and thus is a feasible technique for DCE-MRI in the abdomen and thorax. • Dynamic contrast-enhanced magnetic resonance imaging (DCE) MRI is important in oncological imaging • Radial MRI with k-space weighted image contrast (KWIC) reconstruction offers potential improvements • Radial DCE-MRI provides good image quality, reduced artefacts and high spatial/temporal resolution.

Pulmonary Vein Isolation Supported by MRI‐Derived 3D‐Augmented Biplane Fluoroscopy: A Feasibility Study and a Quantitative Analysis of the Accuracy of the Technique

Despite the advancement of technology in electroanatomic mapping systems (EAMS), fluoroscopy remains a necessary, basic imaging modality for electrophysiology procedures. We present a feasibility study of new software that enables 3D-augmented fluoroscopy in biplane catheterization laboratories for planning and guidance of pulmonary vein isolation (PVI). The computer-assisted overlay registration accuracy was assessed in a clinical setting using an automatic calculation of overlay projection geometry that was derived from hardware sensors in C-arms, detectors, and patient table. Consecutive patients (n = 89) underwent left atrium (LA) magnetic resonance imaging MRI scan prior to PVI. Ideal ablation lines encircling the ipsilateral pulmonary veins (PVs) at antral level were drawn onto the segmented LA surface. The 3D-model was superimposed onto biplane fluoroscopy and matched with angiographies of LA and PVs. Three-dimensional-overlay projection geometry was automatically calculated from C-arm, detectors, and table sensors. Accuracy of technique was assessed as alignment of MRI-derived 3D overlay and angiographic LA/PV anatomy. Integrity of registered overlay was quantified using landmark measurements. Alignment offsets were 1.3 ± 1.5 mm in left PV, 1.2 ± 1.5 mm in right PV, and 1.1 ± 1.4 mm in LA roof region. Bravais-Pearson correlation of the landmark measurements was r = 0.978 (s < 0.01), mean offset between landmark distance measurements was 1.4 ± 0.78 mm. Average time needed for overlay registration was 9.5 ± 3.5 seconds. MRI-derived 3D-augmented fluoroscopy demonstrated a high level of accuracy when compared with LA/PV angiography. The new system could be especially useful to guide procedures not supported by EAMS, such as cryotechnique PVI.

Efficient Segmentation of Medical MRI Image using WT-WS Algorithm

Image segmentation is an important processing step in many image, video and computer vision applications especially in medical field. Extensive research has been done in creating many different approaches and algorithms for image segmentation, but it is still difficult to assess whether one algorithm produces more accurate segmentations than the other. Up to date, the most common method for evaluating the effectiveness of a segmentation method is subjective evaluation, in which a human visually compares the image segmentation results for separate segmentation algorithms, which is a tedious process. The use of computer-aided diagnosis (CAD) systems to improve the sensitivity and specificity of tumor detection has become a focus of medical imaging and diagnostic radiology research. Accurate segmentation of medical images is an important step in contouring during radiotherapy planning. This paper provides new hybrid medical image segmentation method based on Watershed and Wavelet Transform. In this paper, we propose an algorithm for segmentation problems in medical imaging modalities especially for brain Magnetic Resonance Images MRI). The watershed transformation is a useful morphological segmentation tool used for a variety of greyscale images. The segmentation procedure consists of pyramid representation, image segmentation, region merging and region projection. Each layer is split into a number of regions by rooting, labeling technique and the boundary is extracted by threshold and the image is smoothened by wavelet transform. Experimental results prove that the proposed algorithm is comparatively better than the existing systems .

Clinical outcome of preoperative breast MRI for early-stage breast cancer.

42 Background: Preoperative breast magnetic resonance imaging MRI is used in clinical practice to improve oncologic outcome of breast cancer. Concerns over increased rate of unnecessary mastectomies and additional biopsies have been raised. The purpose of our study is to review the outcome of preoperative breast MRI at our institution. Methods: The current study is a retrospective review of 215 patients with early stage breast cancer who underwent definitive surgery. Breast MRI is being used at our institution within the context of multidisciplinary approach. Patients who had complete clinical, radiologic, and pathological data available were identified and formed the basis of this analysis. Results: 215 patients were diagnosed with breast cancer stage I-II in the period of 2006-2012 and had complete data for review. 92 patients out of 215 (43%) had breast MRI prior to definitive surgery. both groups were different in regard of age. Rate of breast conservative surgery, mastectomies, and re-excision for positive margins was similar in both groups. 6 patients out of 12 patients who had breast MRI and underwent bilateral mastectomies were found to have abnormal pathological findings (DCIS 3, LCIS 1, invasive ductal carcinoma 1, and focal epithelial atypia 1). Time from first diagnostic procedure to definitive surgery was similar in both groups (29 days vs. 27.5 days). 38 (41%) patients out of 92 who had breast MRI underwent additional breast biopsies for suspicious lesions with only 8 (21%) patients found to have abnormal pathological findings. Conclusions: Use of breast MRI prior to definitive surgery for early stage breast cancer was associated with increased rate of additional biopsies for suspicious lesions with no favorable effect on re-excision rate. [Table: see text]

Does Neurologic Deterioration Help to Differentiate between Pseudoprogression and True Disease Progression in Newly Diagnosed Glioblastoma Multiforme?

Enlarging or new lesions frequently appear on magnetic resonance imaging (mri) after concurrent administration of radiation therapy and temozolomide in glioblastoma multiforme (gbm) patients. However, in nearly half such cases, the observed radiologic changes are not due to true disease progression, but instead are a result of a post-radiation inflammatory state called "pseudoprogression." Retrospective studies have reported that neurologic deterioration at the time of the post-chemoradiotherapy mri is found more commonly in patients with true disease progression. We report a gbm patient with both radiologic progression on the post-chemoradiotherapy mri and concomitant neurologic deterioration, and we caution against incorporating clinical deterioration into the management schema of patients with possible pseudoprogression.

Management of a suspicious adnexal mass: a clinical practice guideline.

What is the optimal strategy for preoperative identification of the adnexal mass suspicious for ovarian cancer? What is the most appropriate surgical procedure for a woman who presents with an adnexal mass suspicious for malignancy? In Canada in 2010, 2600 new cases of ovarian cancer were estimated to have been diagnosed, and of those patients, 1750 were estimated to have died, making ovarian cancer the 7th most prevalent form of cancer and the 5th leading cause of cancer death in Canadian women. Women with ovarian cancer typically have subtle, nonspecific symptoms such as abdominal pain, bloating, changes in bowel frequency, and urinary or pelvic symptoms, making early detection difficult. Thus, most ovarian cancer cases are diagnosed at an advanced stage, when the cancer has spread outside the pelvis. Because of late diagnosis, the 5-year relative survival ratio for ovarian cancer in Canada is only 40%. Unfortunately, because of the low positive predictive value of potential screening tests (cancer antigen 125 and ultrasonography), there is currently no screening strategy for ovarian cancer. The purpose of this document is to identify evidence that would inform optimal recommended protocols for the identification and surgical management of adnexal masses suspicious for malignancy. Outcomes of interest for the identification question included sensitivity and specificity. Outcomes of interest for the surgical question included optimal surgery, overall survival, progression-free or disease-free survival, reduction in the number of surgeries, morbidity, adverse events, and quality of life. After a systematic review, a practice guideline containing clinical recommendations relevant to patients in Ontario was drafted. The practice guideline was reviewed and approved by the Gynecology Disease Site Group and the Report Approval Panel of the Program in Evidence-based Care. External review by Ontario practitioners was obtained through a survey, the results of which were incorporated into the practice guideline. These recommendations apply to adult women presenting with a suspicious adnexal mass, either symptomatic or asymptomatic. IDENTIFICATION OF AN ADNEXAL MASS SUSPICIOUS FOR OVARIAN CANCER: Sonography (particularly 3-dimensional sonography), magnetic resonance imaging (mri), and computed tomography (ct) imaging are each recommended for differentiating malignant from benign ovarian masses. However, the working group offers the following further recommendations, based on their expert consensus opinion and a consideration of availability, access, and harm: Where technically feasible, transvaginal sonography should be the modality of first choice in patients with a suspicious isolated ovarian mass.To help clarify malignant potential in patients in whom ultrasonography may be unreliable, mri is the most appropriate test.In cases in which extra-ovarian disease is suspected or needs to be ruled out, ct is the most useful technique.Evaluation of an adnexal mass by Doppler technology alone is not recommended. Doppler technology should be combined with a morphology assessment.Ultrasonography-based morphology scoring systems can be used to differentiate benign from malignant adnexal masses. These scoring systems are based on specific ultrasound parameters, each with several scores base on determined features. All evaluated scoring systems were found to have an acceptable level of sensitivity and specificity; the choice of scoring system may therefore be made based on clinician preference.As a standalone modality, serum cancer antigen 125 is not recommended for distinguishing between benign and malignant adnexal masses.Frozen sections for the intraoperative diagnosis of a suspicious adnexal mass is recommended in settings in which availability and patient preference allow. SURGICAL PROCEDURES FOR AN ADNEXAL MASS SUSPICIOUS FOR MALIGNANCY: To improve survival, comprehensive surgical staging with lymphadenectomy is recommended for the surgical management of patients with early-stage ovarian cancer. Laparoscopy is a reasonable alternative to laparotomy, provided that appropriate surgery and staging can be done. The choice between laparoscopy and laparotomy should be based on patient and clinician preference. Discussion with a gynecologic oncologist is recommended. Fertility-preserving surgery is an acceptable alternative to more extensive surgery in patients with low-malignant-potential tumours and those with well-differentiated surgical stage i ovarian cancer. Discussion with a gynecologic oncologist is recommended.

SU‐E‐I‐24: Determining the Optimal B‐Values to Use in Diffusion Weighted Imaging for Differentiating Benign and Malignant Breast Lesions

To investigate and determine the optimal b-values for Diffusion Weighted Imaging(DWI) for Apparent Diffusion Coefficient(ADC) maps in differentiating normal, benign and malignant breast tissue. Twenty-five patients underwent diffusion-weighted magnetic resonance imaging (DWI-MRI) and conventional breast MRI with suspicious breast fmdings(BIRADS >4). Breast lesions were defined by pathology. The DWI was acquired with different b-values ranging from 0,500, 600,750 and 1000s/mm2 . Apparent Diffusion Coefficient(ADC) maps of breast tissue were constructed using different b-values, e.g., using either 2 b-values(0- 1000) or combinations of 3 or more (0,500,1000 or 0,600,750,1000). Quantitative analyses of the ADC maps of glandular, fatty and lesion tissue were obtained. Ratios of lesion to glandular tissue(L/GT) and signal to noise(SNR) were assessed. Paired t-tests were performed for statistical significance. Eighteen patients had invasive ductal carcinoma and 7 had benign breast lesions. The mean ADC value for malignant lesions using all b values was 1.17±0.16×10-3mm2 /s with a lesion to glandular(L/GT) ratio=0.65. The benign lesions, ADC map value was 1.86±0.03×10-3mm2 /s with L/GT=0.98. There was a significant difference(P<0.05) between benign and malignant lesions ADC map value.The lowest SNR(12±6) was with single b-values. There was a significant difference(P<0.05) in SNR with multiple b-values(34±6) compared to single b-values. The highest SNR was given by using two b values greater than 500. Finally, the background noise for all combinations was surprising stable and ranged between 60±20%. This is the first study to investigate the effect of changing different b values in DWI breast imaging. There were significant differences in the SNR between single and multiple b values. Our data show suggest that the recommended b-values for DWI in breast are 0, and two that are 500 or greater. Therefore use of at least 3 b-values in DWI/ADC mapping of breast lesions are needed for better characterization of benign and malignant breast tissue. P50CA88843, Avon Foundation for Women:01-2008-012, U01CA070095, andU01CA140204.

Computer-aided diagnosis of prostate cancer in the peripheral zone using multiparametric MRI

This study evaluated a computer-assisted diagnosis (CADx) system for determining a likelihood measure of prostate cancer presence in the peripheral zone (PZ) based on multiparametric magnetic resonance (MR) imaging, including T2-weighted, diffusion-weighted and dynamic contrast-enhanced MRI at 1.5 T. Based on a feature set derived from grey-level images, including first-order statistics, Haralick features, gradient features, semi-quantitative and quantitative (pharmacokinetic modelling) dynamic parameters, four kinds of classifiers were trained and compared : nonlinear support vector machine (SVM), linear discriminant analysis, k-nearest neighbours and naïve Bayes classifiers. A set of feature selection methods based on t-test, mutual information and minimum-redundancy–maximum-relevancy criteria were also compared. The aim was to discriminate between the relevant features as well as to create an efficient classifier using these features. The diagnostic performances of these different CADx schemes were evaluated based on a receiver operating characteristic (ROC) curve analysis. The evaluation database consisted of 30 sets of multiparametric MR images acquired from radical prostatectomy patients. Using histologic sections as the gold standard, both cancer and nonmalignant (but suspicious) tissues were annotated in consensus on all MR images by two radiologists, a histopathologist and a researcher. Benign tissue regions of interest (ROIs) were also delineated in the remaining prostate PZ. This resulted in a series of 42 cancer ROIs, 49 benign but suspicious ROIs and 124 nonsuspicious benign ROIs. From the outputs of all evaluated feature selection methods on the test bench, a restrictive set of about 15 highly informative features coming from all MR sequences was discriminated, thus confirming the validity of the multiparametric approach. Quantitative evaluation of the diagnostic performance yielded a maximal area under the ROC curve (AUC) of 0.89 (0.81–0.94) for the discrimination of the malignant versus nonmalignant tissues and 0.82 (0.73–0.90) for the discrimination of the malignant versus suspicious tissues when combining the t-test feature selection approach with a SVM classifier. A preliminary comparison showed that the optimal CADx scheme mimicked, in terms of AUC, the human experts in differentiating malignant from suspicious tissues, thus demonstrating its potential for assisting cancer identification in the PZ.

Indicación de pruebas de imagen en pacientes con hepatopatía crónica

The main indications for the use of imaging techniques in the management of patients with chronic liver diseases are: a) monitoring the progression of the disease (diagnosis of cirrhosis), b) diagnosing the presence of complications of cirrhosis (portal hypertension, portal vein thrombosis, ascites), c) screening of hepatocellular carcinoma en high risk patients, d) characterizing focal liver lesions appearing in the follow-up, and e) staging of the neoplasia in patients diagnosed of hepatocellular carcinoma or colangiocarcinoma.For these indications, the different imaging techniques (elastography, ultrasound Doppler, contrast-enhanced ultrasound-CEUS, computerized tomography-CT, magnetic resonance imaging-MRI) should be applied depending on their cost-benefit balance and possible risks. This article summarizes the current knowledge about this issue…

Prediction of Liver Function by Using Magnetic Resonance-based Portal Venous Perfusion Imaging

To evaluate whether liver function can be assessed globally and spatially by using volumetric dynamic contrast-enhanced magnetic resonance imaging MRI (DCE-MRI) to potentially aid in adaptive treatment planning. Seventeen patients with intrahepatic cancer undergoing focal radiation therapy (RT) were enrolled in institution review board-approved prospective studies to obtain DCE-MRI (to measure regional perfusion) and indocyanine green (ICG) clearance rates (to measure overall liver function) prior to, during, and at 1 and 2 months after treatment. The volumetric distribution of portal venous perfusion in the whole liver was estimated for each scan. We assessed the correlation between mean portal venous perfusion in the nontumor volume of the liver and overall liver function measured by ICG before, during, and after RT. The dose response for regional portal venous perfusion to RT was determined using a linear mixed effects model. There was a significant correlation between the ICG clearance rate and mean portal venous perfusion in the functioning liver parenchyma, suggesting that portal venous perfusion could be used as a surrogate for function. Reduction in regional venous perfusion 1 month after RT was predicted by the locally accumulated biologically corrected dose at the end of RT (P<.0007). Regional portal venous perfusion measured during RT was a significant predictor for regional venous perfusion assessed 1 month after RT (P<.00001). Global hypovenous perfusion pre-RT was observed in 4 patients (3 patients with hepatocellular carcinoma and cirrhosis), 3 of whom had recovered from hypoperfusion, except in the highest dose regions, post-RT. In addition, 3 patients who had normal perfusion pre-RT had marked hypervenous perfusion or reperfusion in low-dose regions post-RT. This study suggests that MR-based volumetric hepatic perfusion imaging may be a biomarker for spatial distribution of liver function, which could aid in individualizing therapy, particularly for patients at risk for liver injury after RT.

Anterior visual pathway assessment by magnetic resonance imaging in normal‐pressure glaucoma

To analyze the axonal architecture of the optic nerve in patients with normal-pressure glaucoma and determine whether these parameters correlate with the disease severity. Using magnetic resonance (MRI) imaging (1.5-Tesla unit) and diffusion tensor (DT) MRI, we measured the optic nerve diameter, optic chiasm height and lateral geniculate nucleus (LGN) volume in patients with normal-pressure glaucoma and an age-matched control group. The retinal nerve fibre layer thickness (RNFL) was determined by optical coherence tomography (OCT). The study included 30 patients with normal-pressure glaucoma and 30 age-matched control subjects. Optic nerve diameter (p < 0.001), optic chiasm height (p < 0.001) and LGN volume (p = 0.02) were significantly smaller in the glaucoma group than in the control group and were significantly correlated with RNFL thickness and perimetric loss. In the control group, the parameters significantly (p < 0.05) decreased with age. The DT-MRI-derived fractional anisotropy for the optic nerve was significantly lower (p < 0.001), and the DT-MRI-derived mean diffusivity (p < 0.001), radial diffusivity (λ(⊥) ; p < 0.001) and axial diffusivity (λ(||) ; p = 0.009) for the optic nerve were significantly higher in the glaucoma group and significantly correlated with RNFL thickness and mean perimetric defect. Patients with normal-pressure glaucoma show an age-adjusted reduced optic nerve diameter, optic chiasm height and LGN volume as measured by MRI, correlating with a reduced RNFL thickness and increased perimetric loss. MRI may be applied to examine the optic nerve in patients with glaucoma with opaque optic media.

Catheter-Induced Thrombosis of the Superior Vena Cava

There has been an increase in the use of central venous catheters (CVCs) in clinical practice. One of the most dangerous complications associated with their use is symptomatic or asymptomatic thrombosis (T), sometimes associated with superior vena cava (SVC) syndrome, resulting from impaired venous drainage. The right heart clots can induce an increased risk of mortality due the potential pulmonary embolism (PE). We report a case of asymptomatic 83-year-old woman in whom the thrombosis was detected after an echocardiogram. Echocardiography demonstrated a cardiac mass, and the T was confirmed by (magnetic resonance imaging) MRI. The clinical scenario, a high index of suspicion and routine use of echocardiogram in patients with CVC, can lead to a correct diagnosis, preventing dangerous complications.

P-802 - The structure and connectivity of brain regions involved in emotion processing are modulated by 5HTTLPR x COMT epistasis

Imaging genetic studies provide for the possibility to uncover endophenotypes for neuropsychiatric disorders. To establish neuroimaging correlates of the joint effect of serotonergic (5-HTTLPR) and dopaminergic (COMT) genes. To examine an interaction of 5-HTTLPR and COMT markers on effective connectivity and regional brain volume in healthy individuals. Ninety one healthy Caucasian adults underwent functional magnetic resonance imaging (fMRI) and structural MRI. In fMRI study the participants were presented with videoclips of dynamic emotional facial expressions of fear, sadness, happiness and anger. The effective connectivity within the emotion processing circuitry was assessed with Granger causality method. In the structural neuroimaging part of the study we applied diffeomorphic anatomic registration through exponentiated Lie algebra (DARTEL) whole-brain voxel-based morphometry (VBM). In fear processing condition, an interaction between 5-HTTLPR ( S) and COMT (met) low activity alleles was associated with reduced effective connectivity within the facial emotion processing circuitry. The results of the structural data analysis showed an interaction of COMT and 5-HTTLPR genotypes with regional grey matter volume in bilateral parahippocampal gyrus, amygdala, hippocampus, cerebellum and right putamen. In particular, the gray matter volume in these regions was smaller in individuals who were both COMT- met and 5-HTTLPR- S carriers, as compared to those carrying either 5-HTTLPR- L/L, or COMT- val/val . The epistatic effect of COMT- met and 5-HTTLPR- S markers impacts on both the brain function and structure and may underlie an inefficient emotion regulation.