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Imaging Modalities (imaging + modality)
Kinds of Imaging Modalities Selected AbstractsVasodilator Stress Induces Infrequent Wall Thickening Abnormalities Compared to Perfusion Defects in Mild-to-Moderate Coronary Artery Disease: Implications for the Choice of Imaging Modality with Vasodilator StressECHOCARDIOGRAPHY, Issue 4 2004M.R.C.P., Ph.D., Prem Soman M.D. Background: Experimental evidence suggests that although vasodilator stress agents consistently induce regional flow disparity between stenosed and normal coronary vascular beds, the occurrence of functional myocardial ischemia is infrequent, especially in mild-to-moderate coronary artery stenosis. Thus, it is hypothesized that dipyridamole infusion, even at high doses, will result in a disproportionately higher frequency of perfusion defects compared to regional wall thickening abnormalities. Methods: We performed simultaneous high-dose (0.84 mg/kg) dipyridamole stress echocardiography (Echo) and Tc-99m sestamibi SPECT (MIBI, methoxyisobutyl isonitrile) in 46 patients with coronary artery diameter stenosis >50% and ,90% in one or two epicardial coronary arteries, and no previous myocardial infarction. Results: Of a total of 828 segments, MIBI showed 97 reversible defects while Echo showed only 23 reversible wall thickening abnormalities. Of the 97 segments with reversible MIBI defects, only 13 (13%) showed simultaneous reversible wall thickening abnormalities during dipyridamole infusion. There were 24 patients with MIBI defects, of whom 10 (41%) showed a corresponding wall thickening abnormality. The sensitivity of MIBI and Echo for the detection of coronary artery disease was 52% and 21%, respectively (P = 0.001). Conclusion: This suggests that vasodilator stress is not optimally suited for use with techniques that use regional wall thickening abnormality as a marker of ischemia for the diagnosis of coronary artery disease. (ECHOCARDIOGRAPHY, Volume 21, May 2004) [source] Development of a Quadruple Imaging Modality by Using NanoparticlesCHEMISTRY - A EUROPEAN JOURNAL, Issue 37 2009Won Hwang Abstract The combination of nanotechnology with molecular imaging has great potential for the development of diagnostics and therapeutics, and multimodal imaging enables versatile applications from cell tracking in animals to clinical applications. Herein, we report a multimodal nanoparticle imaging system that is capable of concurrent fluorescence, bioluminescence, bioluminescence resonance energy transfer (BRET), positron emission tomography (PET) and magnetic resonance (MR) imaging in vivo. A cobalt,ferrite nanoparticle surrounded by rhodamine (MF) was conjugated with luciferase (MFB) and p -SCNbnNOTA (2-(4-isothiocyanatobenzyl)-1,4,7-triazacyclonane-1,4,7-triacetic acid) followed by 68GaCl3 (magnetic-fluorescent-bioluminescent-radioisotopic particle, MFBR). Confocal microscopy revealed good transfection efficiency of MFB into cells and BRET was also observed in MFB. A good correlation among rhodamine, luciferase, and 68GaCl3 was found in MFBR, and the activities of each imaging modality increased dose-dependently with the amount of MFBR in the C6 cells. In vivo optical images were acquired from the thighs of mice after intramuscular and subcutaneous injections of MFBR-laden cells. MicroPET and MR images showed intense radioactivity and ferromagnetic intensities with MFBR-laden cells. The multimodal imaging strategy could be used as potential imaging tools to track cells. [source] In Vivo mouse imaging and spectroscopy in drug discoveryNMR IN BIOMEDICINE, Issue 3 2007Nicolau Beckmann Abstract Imaging modalities such as micro-computed tomography (micro-CT), micro-positron emission tomography (micro-PET), high-resolution MRI, optical imaging, and high-resolution ultrasound have become invaluable tools in preclinical pharmaceutical research. They can be used to non-invasively investigate, in vivo, rodent biology and metabolism, disease models, and pharmacokinetics and pharmacodynamics of drugs. The advantages and limitations of each approach usually determine its application, and therefore a small-rodent imaging laboratory in a pharmaceutical environment should ideally provide access to several techniques. In this paper we aim to illustrate how these techniques may be used to obtain meaningful information for the phenotyping of transgenic mice and for the analysis of compounds in murine models of disease. Copyright © 2007 John Wiley & Sons, Ltd. [source] Left Coronary Artery Arteriovenous Malformation Presenting as a Diastolic Murmur with Exercise Intolerance in a Child with a Suspected Familial Vascular Malformation SyndromeCONGENITAL HEART DISEASE, Issue 3 2007Valerie A. Schroeder MD Abstract Objective., Intracardiac arteriovenous malformations are rare and may be associated with sudden death in adults. This case report describes an intracardiac left coronary arteriovenous malformation in a 7-year-old boy with a suspected familial cutaneous vascular malformation syndrome. The patient presented with a diastolic murmur, exercise intolerance, chest pain, and a left ventricular mass. Methods., The left ventricular mass was initially identified by echocardiography. Subsequently, a computed tomography scan revealed the vascular nature of the lesion. We hypothesized that the lesion represented either an arteriovenous malformation (AVM) or a hemangioma. These lesions are thought to cause coronary steal and myocardial dysfunction. Skin biopsies of the patient's cutaneous lesions revealed capillary hyperplasia, which was not consistent with either hemangioma or AVM. Thus, a surgical biopsy and partial resection of the mass was performed. Results., The surgical pathology of the cardiac mass was consistent with an AVM. Within 6 months following partial resection of the mass, the patient unexpectedly developed a left ventricular pseudoaneurysm at the resection site and required re-operation. Although a portion of the mass remains, both the patient's chest pain and exercise tolerance have improved subjectively. Conclusion., Patients with cutaneous vascular malformations and diastolic murmurs, as well as cardiac symptoms, should undergo echocardiography or alternative imaging modalities to screen for treatable pathological myocardial vascular malformations. [source] Tumor imaging in small animals with a combined micro-CT/micro-DSA system using iodinated conventional and blood pool contrast agentsCONTRAST MEDIA & MOLECULAR IMAGING, Issue 4 2006Cristian T. Badea Abstract X-ray based micro-computed tomography (CT) and micro-digital subtraction angiography (DSA) are important non-invasive imaging modalities for following tumorogenesis in small animals. To exploit these imaging capabilities further, the two modalities were combined into a single system to provide both morphological and functional data from the same tumor in a single imaging session. The system is described and examples are given of imaging implanted fibrosarcoma tumors in rats using two types of contrast media: (a) a new generation of blood pool contrast agent containing iodine with a concentration of 130,mg/mL (FenestraÔ VC, Alerion Biomedical, San Diego, CA, USA) for micro-CT and (b) a conventional iodinated contrast agent (Isovue®-370,mg/mL iodine, trademark of Bracco Diagnostics, Princeton, NJ, USA) for micro-DSA. With the blood pool contrast agent, the 3D vascular architecture is revealed in exquisite detail at 100,µm resolution. Micro-DSA images, in perfect registration with the 3D micro-CT datasets, provide complementary functional information such as mean transit times and relative blood flow through the tumor. This imaging approach could be used to understand tumor angiogenesis better and be the basis for evaluating anti-angiogenic therapies. Copyright © 2006 John Wiley & Sons Ltd. [source] Applications of cone-beam computed tomography in fractures of the maxillofacial complexDENTAL TRAUMATOLOGY, Issue 4 2009Werner H. Shintaku Several studies support the use of conventional two-dimensional imaging for traumas involving mainly the mandible, but for more complex situations advanced imaging modalities such as computed tomography (CT) and magnetic resonance imaging have higher indication. Nowadays, besides CT, cone-beam computed tomography (CBCT) has appeared as a reasonable and reliable alternative considering radiation dosage, image quality and comfort for the patient. The purpose of this study was to review the fracture patterns involving the maxillofacial complex, provide a technical and practical comparison between CT and CBCT, and finally present the potential applications of CBCT illustrated with clinical examples. [source] Solid renal masses in adults: Image-guided fine-needle aspiration cytology and imaging techniques,"Two Heads Better Than One?"DIAGNOSTIC CYTOPATHOLOGY, Issue 1 2008José García-Solano M.D. Abstract We have compared the diagnostic accuracy of image-guided 25G-FNA (fine-needle aspiration) and imaging modalities in a group of 31 patients with solid space-occupying renal lesions. All patients had undergone total nephrectomy and histologic sections were available for review. By FNA there were 24 malignant diagnoses, I benign diagnosis, and 6 cases with yield inadequate for diagnosis. The FNA accuracy for malignancy was 100% with no false positive cases; cancer typing by FNA matched the final histologic diagnoses in 91.6% of cases. Sensitivity, specificity, positive predictive value, and negative predictive value were 80%, 14%, 80%, and 14%, respectively. Radiologically there were 26 diagnoses of malignancy, I of benignity, and 4 indeterminate lesions (IL). Accuracy for malignancy was 100%, with one false positive case; cancer typing matched the final histologic diagnoses in 84%. Sensitivity of imaging modalities was 86%, specificity 17%, positive predictive value 83%, and negative predictive value 20%. Four IL corresponded to renal cell carcinoma in the final histologic report: two IL had a previous diagnosis of malignancy by FNA, and the yield of two was inadequate for cytologic diagnosis. Both techniques have 100% accuracy for the diagnosis of malignancy. The sensitivity, specificity, positive predictive value, and negative predictive value of imaging techniques are slightly higher than those obtained by FNA. Imaging techniques and FNA of solid renal masses complement each other in IL and in nondiagnostic FNAs. Diagn. Cytopathol. 2008;36:8,12. © 2007 Wiley-Liss, Inc. [source] WHAT KIND OF BENEFIT DO WE EXPECT FOR PERORAL PANCREATOSCOPY IN THE DIAGNOSIS OF INTRADUCTAL PAPILLARY MUCINOUS TUMOR OF THE PANCREAS?DIGESTIVE ENDOSCOPY, Issue 2006Taketo Yamaguchi Intraductal papillary mucinous tumor (IPMT) of the pancreas is characterized by slow growth and a relatively favorable prognosis, however, invasive cancer originating in an IPMT is associated with a poor prognosis. Although various parameters in imaging modalities have been advocated to differentiate between benign IPMN and malignant ones, it is not easy to obtain definite diagnosis based on these parameters. Peroral pancreatoscopy (POPS) allows a clear and direct visualization of the pancreatic duct, providing useful information regarding tumor nature in IPMT. The authors have studied the usefulness of POPS in the diagnosis of IPMT. Nevertheless, its usefulness is not necessarily widely accepted and the significance of POPS is still controversial. In this review, the authors intended to address the diagnostic value of POPS and to clarify its role in the diagnosis of IPMT. The authors think treatment of IPMT can be improved by introducing POPS because the determination of surgical procedure as well as the area of resection based on the preoperative diagnosis of the involvement of the main pancreatic duct and branch duct is inevitable. [source] The Relation between the Color M-Mode Propagation Velocity of the Descending Aorta and Coronary and Carotid Atherosclerosis and Flow-Mediated DilatationECHOCARDIOGRAPHY, Issue 3 2010Yilmaz Gunes M.D. Background: To improve clinical outcomes, noninvasive imaging modalities have been proposed to measure and monitor atherosclerosis. Common carotid intima-media thickness (CIMT) and brachial artery flow-mediated dilatation (FMD) have correlated with coronary atherosclerosis. Recently, the color M-mode-derived propagation velocity of descending thoracic aorta (AVP) was shown to be associated with coronary artery disease (CAD). Methods: CIMT, FMD, and AVP were measured in 92 patients with CAD and 70 patients having normal coronary arteries (NCA) detected by coronary angiography. Patients with acute myocardial infarction, renal failure or hepatic failure, aneurysm of aorta, severe valvular heart disease, left ventricular ejection fraction <40%, atrial fibrillation, frequent premature beats, left bundle branch block, and inadequate echocardiographic image quality were excluded. Results: Compared to patients with normal coronary arteries, patients having CAD had significantly lower AVP (29.9 ± 8.1 vs. 47.5 ± 16.8 cm/sec, P < 0.001) and FMD (5.3 ± 1.9 vs. 11.4 ± 5.8%, P < 0.001) and higher CIMT (0.94 ± 0.05 vs. 0.83 ± 0.14 mm, P < 0.001) measurements. There were significant correlations between AVP and CIMT (r =,0.691, P < 0.001), AVP and FMD (r = 0.514, P < 0.001) and FMD and CIMT (r =,0.530, P < 0.001). Conclusions: The transthoracic echocardiographic determination of the color M-mode propagation velocity of the descending aorta is a simple practical method and correlates well with the presence of carotid and coronary atherosclerosis and brachial endothelial function. (Echocardiography 2010;27:300-305) [source] Saphenous Vein Graft Aneurysm Masquerading as a Right Atrial MassECHOCARDIOGRAPHY, Issue 3 2005Leonid Yatskar M.D. We report a case of a large saphenous vein graft (SVG) aneurysm masquerading as a right atrial mass on transesophageal echocardiogram. Cardiac magnetic resonance angiography reliably made a diagnosis of SVG aneurysm extrinsically compressing right atrium. This case illustrates the importance of using combined imaging modalities for the diagnosis and management of cardiac masses. [source] Viable Myocardium: How Much Is Enough?ECHOCARDIOGRAPHY, Issue 1 2005A Comparison of Viability by Comparative Imaging Techniques to Assess the Quantity, Functionality of Ischemic Myocardium Left ventricular systolic dysfunction is mainly a result of coronary artery disease (CAD). Decrease in myocardial contractility results as a response to a chronic hypoperfusion state that produces a change in cardiac myocyte metabolism, resulting in a perfusion-contraction mismatch in which function is sacrificed for survival. If revascularization is performed in a timely fashion, metabolism can be restored leading to recovery of function. Through the use of noninvasive imaging modalities, assessing myocardial viability can be easily performed and will aid in selecting those patients who will benefit from revascularization. Viable myocardium can be identified by nuclear modalities that have a high sensitivity but a lower specificity, such as thallium-201 single photon emission computed tomography and positron emission tomography (PET); or by the use of dobutamine stress echocardiogram (DSE), which has a decreased sensitivity but a better specificity. A modality that is increasingly being used with an overall good sensitivity and specificity is contrast-enhanced magnetic resonance imaging. The purpose of this review is to explore the amount of myocardial viability that is relevant to pursue revascularization, since as myocardial function improves there is a decrease in morbidity and mortality from heart failure and arrhythmias. [source] Role of Dobutamine Stress Echocardiography for Preoperative Cardiac Risk Assessment Before Major Vascular Surgery: A Diagnostic Tool Comes of AgeECHOCARDIOGRAPHY, Issue 1 2000DON POLDERMANS M.D. Background: Cardiac complications are a major cause for perioperative mortality and morbidity Also, the presence and severity of underlying coronary artery disease (CAD) determine long-ten prognosis after successful surgery. Aim: This overview evaluates the additional value ofdobutamir, stress echocardiography (DSE) to common clinical cardiac risk factors and other noninvasii cardiac imaging modalities for perioperative and late cardiac prognosis. Results: DSE provides tl attending physician with preoperative prognostic information for perioperative and long-ten prognosis for cardiac events. It also enables the selection of high risk patients for evaluation i cardiac risk reduction therapies. Conclusions: DSE is a useful tool for preoperative cardiac ris evaluation in addition to common clinical cardiac risk factors. (ECHOCARDIOGRAPHY, Vo ume 17, January 2000) [source] Detection of artificially induced vertical radicular fractures using Tuned Aperture Computed TomographyEUROPEAN JOURNAL OF ORAL SCIENCES, Issue 6 2001Madhu K. Nair This study compared the accuracy of three imaging modalities for the detection of artificially induced vertical root fractures (VRF) on teeth in cadaver mandibles. Fifty-four single-rooted, endodontically treated mandibular teeth being prepared to carry posts were evaluated using direct digital radiography (DDI) with a Schick sensor, unprocessed Tuned Aperture Computed Tomography® (TACT-U) images and iteratively restored TACT (TACT-IR) images. Twenty-eight of these teeth had been subjected to fracture induction using an apically driven force. Nine basis images were used for each TACT image generation. Eight observers used a five-point confidence rating scale to record the confidence with which they considered a fracture to be present or not. Sensitivity and specificity values were computed and receiver operating characteristic (ROC) curves were generated. The areas under the curves (Az) used as an indication of the diagnostic accuracy of the imaging system were as follows: DDI: 0.37; TACT-U: 0.77 and TACT-IR: 0.81. DDI was significantly inferior to the TACT modalities. Differences in detection efficacy based on observers and observation sessions were noted on ANOVA and post-hoc Tukey's tests. This study indicates that TACT is the imaging modality of choice for VRF in endodontically treated teeth. [source] Imaging of Mandibular Trauma: ROC AnalysisACADEMIC EMERGENCY MEDICINE, Issue 7 2001Dipl., Madhu K. Nair BDS Objectives: To compare the diagnostic efficacies of panoramic radiographs, mandibular trauma series, and digitized radiographs for detection of fractures of the mandible. Methods: Fractures were induced using blunt trauma in 25 cadaver mandibles. Panoramic radiographs, digitized radiographs, and mandibular series comprising an anteroposterior view, two lateral oblique, and a reverse Towne's were used. Six observers recorded their diagnoses using a five-point confidence rating scale. The data were analyzed using receiver operating characteristic (ROC) curve analysis. Results: Significant differences based on imaging modalities were found (p < 0.0015) in the area under the curves (Az): panoramic radiograph, 0.8762; mandibular series, 0.7521; panoramic plus anteroposterior radiographs combination, 0.8886; and digitized mandibular series, 0.7723. No observer-based differences were noted. Condylar and coronoid fractures were difficult to detect than those in other areas of the mandible (p < 0.033). Intra- and inter-observer agreements were high (,w= 0.81 and 0.76, respectively). Conclusions: Panoramic radiographs are adequate for detection of mandibular fractures. Addition of an anteroposterior view augments diagnostic accuracy. [source] Novel non-invasive approach for visualizing inflamed atherosclerotic plaques using fluorodeoxyglucose-positron emission tomographyGERIATRICS & GERONTOLOGY INTERNATIONAL, Issue 1 2010Hisashi Kai There is an increasing body of evidence that a dynamic inflammatory process plays a role in the initiation, progression and destabilization of atherosclerotic plaques. The biological composition and inflammatory state of an atherosclerotic plaque, rather than the degree of stenosis or its size, are the major determinants of life-threatening events, such as ischemic cerebrovascular accident and acute coronary syndrome. To date, there is no non-invasive method clinically available for visualizing inflammation of individual plaques. Recently, we and others have shown that 18(F)-fluorodeoxyglucose (FDG) uptake, namely inflammation, can be evaluated quantitatively in the aortic, carotid, iliac and femoral plaques by using FDG positron emission tomography (PET) co-registered with computed tomography (FDG-PET/CT). Therefore, FDG-PET/CT, a combined functional and structural wholebody imaging modalities, holds great promise for non-invasive evaluation of inflammation , namely, activity , of atherosclerotic plaques of large arteries. [source] Imaging the large bowel in the elderlyGERIATRICS & GERONTOLOGY INTERNATIONAL, Issue 4 2004Aza Abdulla Diseases of the large bowel are common in older patients and many of these, notably polyps, cancer, diverticular disease and ischemia, increase in incidence with age. A variety of imaging modalities are available in clinical practice but the choice of investigation should take into consideration not only its diagnostic yield but also the ability of the older patient to undergo the procedure with minimal discomfort. Perhaps more important is whether that investigation is likely to have an effect on the overall management of the patient. [source] Oral primary angiosarcoma of the lower lip mucosa: Report of a case in a 15-year-old boyHEAD & NECK: JOURNAL FOR THE SCIENCES & SPECIALTIES OF THE HEAD AND NECK, Issue 10 2008Ignacio Arribas-Garcia MD Abstract Background. Angiosarcomas are rare soft tissue malignant tumors with dismal prognosis. Head and neck involvement is uncommon (5%) and usually affects the scalp or facial skin. Methods and Results. We present the case of an inferior lip mucosal low-grade angiosarcoma in a 15-year-old boy treated exclusively with surgery. One and a half years after treatment, the patient was free of signs of recurrence. Prompt and accurate diagnosis with adequate imaging modalities and multidisciplinary treatment are crucial for optimal management of these neoplasms. Conclusion. Lip mucosal involvement is exceptional with only a few cases described in the literature, all in patients older than 60 years To our knowledge, this is the youngest patient ever reported. © 2008 Wiley Periodicals, Inc. Head Neck, 2008 [source] Improved diagnosis of well-differentiated hepatocellular carcinoma with gadolinium ethoxybenzyl diethylene triamine pentaacetic acid-enhanced magnetic resonance imaging and Sonazoid contrast-enhanced ultrasonographyHEPATOLOGY RESEARCH, Issue 9 2010Natsuko Kawada Aim:, Two new imaging modalities have been developed recently that are directed at the focal liver lesions: gadolinium ethoxybenzyl diethylene triamine pentaacetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance imaging (MRI) and Sonazoid contrast-enhanced ultrasonography (CEUS). We investigated the usefulness of these modalities for the diagnosis of small (<2 cm), well-differentiated hepatocellular carcinoma (HCC). Methods:, A total of 15 nodules from 13 patients, which were histologically diagnosed as well-differentiated HCC, were subjected to this study. Lesions that showed hypervascularity in the arterial phase and washout in the portal or late non-hemodynamic phase were regarded as HCC in the dynamic studies of all imaging modalities. Results:, By multidetector computed tomography (MDCT), six of 15 (40%) nodules were diagnosed as HCC. Gd-EOB-DTPA-enhanced MRI diagnosed HCC in nine of the 15 (60%) nodules. Of the nine nodules that were not diagnosed by MDCT, four could be diagnosed by Gd-EOB-DTPA-enhanced MRI. In Sonazoid CEUS, 10 of 15 nodules (67%) were diagnosed as HCC. Four of nine nodules that could not be diagnosed as HCC by MDCT, were diagnosed by Sonazoid CEUS. A total of 11 of the 15 (73%) nodules were diagnosed as HCC by Gd-EOB-DTPA-enhanced MRI and Sonazoid CEUS in addition to MDCT. Conclusion:, Gd-EOB-DTPA-enhanced MRI and Sonazoid CEUS had greater diagnostic value for small, well-differentiated HCC than did conventional MDCT. [source] Case report of a focal nodular hyperplasia-like nodule present in cirrhotic liverHEPATOLOGY RESEARCH, Issue 5 2008Sho Takahashi An 81-year-old female was referred to Sapporo Medical University Hospital because of a nodular lesion 20 mm in diameter found in the liver S8 during follow-up for type C liver cirrhosis. Abdominal ultrasonography showed a capsule-like structure, and contrast computed tomography revealed hypervascularity at the early phase and inner pooling of the contrast medium with ring enhancement at the late phase. Magnetic resonance T2-weighted imaging (T2WI) demonstrated a hyperintensity nodule with further hyperintensity signals in some parts of the nodule, and the signal pattern differed from that of typical fibrosis. SPIO-magnetic resonance imaging showed partial hypointensity signals by T2WI, which indicated the presence of Kupffer cells. Angiography did not show a spoke-wheel pattern. The results by imaging modalities indicated that the nodule was atypical for hepatocellular carcinoma (HCC) and focal nodular hyperplasia (FNH), and liver nodule biopsy was performed for histological diagnosis. Compared with the background liver, the nodule revealed high cellular density, cellular dysplasia at the periphery, a pseudo-crypt structure and irregular hepatic cord arrangement in some parts of the nodule. Among them, there was immature fibrous tissue containing arterioles with muscular hypertrophy. There has been no report of well-differentiated HCC with a central scar, and this case was presumed to be an FNH-like nodule with dysplasia physically associated with cirrhotic tissue. [source] Multimodal management of neuroendocrine liver metastasesHPB, Issue 6 2010Andrea Frilling Abstract Background:, The incidence of neuroendocrine tumours (NET) has increased over the past three decades. Hepatic metastases which occur in up to 75% of NET patients significantly worsen their prognosis. New imaging techniques with increasing sensitivity enabling tumour detection at an early stage have been developed. The treatment encompasses a panel of surgical and non-surgical modalities. Methods:, This article reviews the published literature related to management of hepatic neuroendocrine metastases. Results:, Abdominal computer tomography, magnetic resonance tomography and somatostatin receptor scintigraphy are widely accepted imaging modalities. Hepatic resection is the only potentially curative treatment. Liver transplantation is justified in highly selected patients. Liver-directed interventional techniques and locally ablative measures offer effective palliation. Promising novel therapeutic options offering targeted approaches are under evaluation. Conclusions:, The treatment of neuroendocrine liver metastases still needs to be standardized. Management in centres of expertise should be strongly encouraged in order to enable a multidisciplinary approach and personalized treatment. Development of molecular prognostic factors to select treatment according to patient risk should be attempted. [source] A diagnostic paradigm for resectable liver lesions: to biopsy or not to biopsy?HPB, Issue 7 2009Adrian B. Cresswell Abstract Background:, Despite a growing body of evidence reporting the deleterious mechanical and oncological complications of biopsy of hepatic malignancy, a small but significant number of patients undergo the procedure prior to specialist surgical referral. Biopsy has been shown to result in poorer longterm survival following resection and advances in modern imaging modalities provide equivalent, or better, diagnostic accuracy. Methods:, The literature relating to needle-tract seeding of primary and secondary liver cancers was reviewed. MEDLINE, EMBASE and the Cochrane Library were searched for case reports and series relating to the oncological complications of biopsy of liver malignancies. Current non-invasive diagnostic modalities are reviewed and their diagnostic accuracy presented. Results:, Biopsy of malignant liver lesions has been shown to result in poorer longterm survival following resection and does not confer any diagnostic advantage over a combination of non-invasive imaging techniques and serum tumour markers. Conclusions:, Given that chemotherapeutic advances now often permit downstaging and subsequent resection of ,unresectable' disease, the time has come to abandon biopsy of solid lesions outside the setting of a specialist multi-disciplinary team meeting (MDT). [source] Pancreatico-duodenectomy for complicated groove pancreatitisHPB, Issue 3 2007SAKHAWAT H. RAHMAN Objectives. Groove pancreatitis (GP) describes a form of segmental pancreatitis, which affects the pancreatic head at the interface with the duodenum, and is frequently associated with ectopic pancreatic tissue in the duodenal wall. We present a series of symptomatic patients with complicated GP who underwent pancreaticoduodenectomy, and review the diagnostic challenges, imaging modalities, pathological features and clinical outcome of this rare condition. Patients and methods. This was a prospective case base study of clinical, radiological and pathological data collected between the years 2000 and 2005 on patients diagnosed with severe GP , confirmed by histopathological examination following pancreaticoduodenectomy. Results. In total 11 patients were included, presenting with chronic abdominal pain (n= 11), gastric outlet obstruction (n= 5) and jaundice (n= 1). Exocrine dysfunction with associated weight loss (median > 9 kg) was present in 10 patients, and type 2 diabetes in 2 patients. Radiological imaging (CT/MRCP/EUS) provided complementary investigations and correlated well with classic histopathological findings (duodenal wall thickening, mucosal irregularity and Brunner's gland hyperplasia, duodenal wall cysts and pancreatic heterotropia). Following pancreaticoduodenectomy (median follow-up period 52 weeks) all patients experienced significant pain alleviation and weight gain (average 3 kg at 2 months). Conclusion. Pancreaticoduodenectomy is associated with significant improvements in weight gain and alleviates the chronic pain associated with severe GP. [source] Nonoperative imaging techniques in suspected biliary tract obstructionHPB, Issue 6 2006Frances Tse Abstract Evaluation of suspected biliary tract obstruction is a common clinical problem. Clinical data such as history, physical examination, and laboratory tests can accurately identify up to 90% of patients whose jaundice is caused by extrahepatic obstruction. However, complete assessment of extrahepatic obstruction often requires the use of various imaging modalities to confirm the presence, level, and cause of obstruction, and to aid in treatment plan. In the present summary, the literature on competing technologies including endoscopic retrograde cholangiopancreatography (ERCP), percutaneous transhepatic cholangiopancreatography (PTC), endoscopic ultrasound (EUS), intraductal ultrasonography (IDUS), magnetic resonance cholangiopancreatography (MRCP), helical CT (hCT) and helical CT cholangiography (hCTC) with regards to diagnostic performance characteristics, technical success, safety, and cost-effectiveness is reviewed. Patients with obstructive jaundice secondary to choledocholithiasis or pancreaticobiliary malignancies are the primary focus of this review. Algorithms for the management of suspected obstructive jaundice are put forward based on current evidence. Published data suggest an increasing role for EUS and other noninvasive imaging techniques such as MRCP, and hCT following an initial transabdominal ultrasound in the assessment of patients with suspected biliary obstruction to select candidates for surgery or therapeutic ERCP. The management of patients with a suspected pancreaticobiliary condition ultimately is dependent on local expertise, availability, cost, and the multidisciplinary collaboration between radiologists, surgeons, and gastroenterologists. [source] Diagnosis of pancreatic cancerHPB, Issue 5 2006Fumihiko Miura Abstract The ability to diagnose pancreatic carcinoma has been rapidly improving with the recent advances in diagnostic techniques such as contrast-enhanced Doppler ultrasound (US), helical computed tomography (CT), enhanced magnetic resonance imaging (MRI), and endoscopic US (EUS). Each technique has advantages and limitations, making the selection of the proper diagnostic technique, in terms of purpose and characteristics, especially important. Abdominal US is the modality often used first to identify a cause of abdominal pain or jaundice, while the accuracy of conventional US for diagnosing pancreatic tumors is only 50,70%. CT is the most widely used imaging examination for the detection and staging of pancreatic carcinoma. Pancreatic adenocarcinoma is generally depicted as a hypoattenuating area on contrast-enhanced CT. The reported sensitivity of helical CT in revealing pancreatic carcinoma is high, ranging between 89% and 97%. Multi-detector-row (MD) CT may offer an improvement in the early detection and accurate staging of pancreatic carcinoma. It should be taken into consideration that some pancreatic adenocarcinomas are depicted as isoattenuating and that pancreatitis accompanied by pancreatic adenocarcinoma might occasionally result in the overestimation of staging. T1-weighted spin-echo images with fat suppression and dynamic gradient-echo MR images enhanced with gadolinium have been reported to be superior to helical CT for detecting small lesions. However, chronic pancreatitis and pancreatic carcinoma are not distinguished on the basis of degree and time of enhancement on dynamic gadolinium-enhanced MRI. EUS is superior to spiral CT and MRI in the detection of small tumors, and can also localize lymph node metastases or vascular tumor infiltration with high sensitivity. EUS-guided fine-needle aspiration biopsy is a safe and highly accurate method for tissue diagnosis of patients with suspected pancreatic carcinoma. 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) has been suggested as a promising modality for noninvasive differentiation between benign and malignant lesions. Previous studies reported the sensitivity and specificity of FDG-PET for detecting malignant pancreatic tumors as being 71,100% and 64,90%, respectively. FDG-PET does not replace, but is complementary to morphologic imaging, and therefore, in doubtful cases, the method must be combined with other imaging modalities. [source] Comparing MEG and fMRI views to naming actions and objectsHUMAN BRAIN MAPPING, Issue 6 2009Mia Liljeström Abstract Most neuroimaging studies are performed using one imaging method only, either functional magnetic resonance imaging (fMRI), electroencephalography (EEG), or magnetoencephalography (MEG). Information on both location and timing has been sought by recording fMRI and EEG, simultaneously, or MEG and fMRI in separate sessions. Such approaches assume similar active areas whether detected via hemodynamic or electrophysiological signatures. Direct comparisons, after independent analysis of data from each imaging modality, have been conducted primarily on low-level sensory processing. Here, we report MEG (timing and location) and fMRI (location) results in 11 subjects when they named pictures that depicted an action or an object. The experimental design was exactly the same for the two imaging modalities. The MEG data were analyzed with two standard approaches: a set of equivalent current dipoles and a distributed minimum norm estimate. The fMRI blood-oxygen-level dependent (BOLD) data were subjected to the usual random-effect contrast analysis. At the group level, MEG and fMRI data showed fairly good convergence, with both overall activation patterns and task effects localizing to comparable cortical regions. There were some systematic discrepancies, however, and the correspondence was less compelling in the individual subjects. The present analysis should be helpful in reconciling results of fMRI and MEG studies on high-level cognitive functions. Hum Brain Mapp, 2009. © 2009 Wiley-Liss, Inc. [source] Evaluation of endoscopic and imaging modalities in the diagnosis of structural disorders of the ileal pouchINFLAMMATORY BOWEL DISEASES, Issue 9 2010Linda Tang MD Abstract Background: Computerized tomography enterography (CTE), gastrograffin enema (GGE), magnetic resonance imaging (MRI), and pouch endoscopy (PES) have commonly been used to assess ileal pouch disorders. However, their diagnostic utility has not been systematically evaluated. The aims of this study were to compare these imaging techniques to each other and to optimize diagnosis of pouch disorders by using a combination of these diagnostic modalities. Methods: Clinical data of patients from the Pouchitis Clinic from 2003 to 2008 who had a PES and at least 1 additional imaging modalities (CTE, GGE, or MRI) used for evaluation of ileal pouch disorders were retrospectively evaluated. We analyzed the accuracy, sensitivity, specificity, negative predictive value (NPV), and positive predictive value (PPV) with which these tests were able diagnose pouch inlet and distal small bowel and pouch outlet strictures, pouch fistulas, sinuses, and leaks. Subsequently, accuracy was recalculated by combining 2 imaging modalities to see if this could enhance accuracy. Results: A total of 66 patients underwent evaluation with PES and 1 other imaging modality as follows: PES + CTE (n = 23), PES + GGE (n = 34), and PES + MRI (n = 26). The mean age was 41.5 ± 14.5 years, with 28 being female (42.4%). Sixty patients (90.9%) had J pouches and 59 (89.4%) had a preoperative diagnosis of ulcerative colitis. Overall, CTE, GGE, MRI, and PES all had reasonable accuracy for the diagnosis of small bowel and inlet strictures (73.9%,95.4%), outlet strictures (87.9%,92.3%), fistula (76.9%,84.8%), sinus (68.0%,93.9%), and pouch leak (83,93.9%). CTE had the lowest accuracy for small bowel and inlet strictures (73.9%) and MRI had the lowest accuracy for pouch sinus (68.0%). Combining 2 imaging tests can increase the accuracy of diagnosis to 100% for strictures, fistulas, sinus, and pouch leaks. Conclusions: CTE, GGE, MRI, and PES offer complementary information on disorders of the pouch and the combination of these tests increases diagnostic accuracy for complex cases. (Inflamm Bowel Dis 2010) [source] On the segmentation of vascular geometries from medical imagesINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING, Issue 1 2010A. G. Radaelli Abstract A comprehensive analysis of vascular morphology and the application of generic models of vascular biomechanics to specific patients require the ability of extracting a geometrical representation of the vascular anatomy from medical images. Owing to the wide range of clinical manifestations of vascular disease and associated imaging modalities and protocols, several segmentation methods have been proposed over the last 20 years and are available in the literature. In this paper, we review the methods of segmentation of angiographic medical images and identify major advantages and disadvantages of state-of-the-art techniques. We further discuss the performance of some of the most popular intensity-based and gradient-based methods using a set of images of peripheral by-pass grafts acquired with magnetic resonance angiography (MRA). We then propose a threshold front method for the segmentation of MRA images and assess its performance using two anatomic scale replica models, reproducing a normal and a stenotic peripheral artery. The threshold front algorithm is a simple, fast and parameter-free (still adaptive) method achieving segmentation errors below pixel resolution. Copyright © 2009 John Wiley & Sons, Ltd. [source] MAP fusion method for superresolution of images with locally varying pixel qualityINTERNATIONAL JOURNAL OF IMAGING SYSTEMS AND TECHNOLOGY, Issue 4 2008Kio Kim Abstract Superresolution is a procedure that produces a high-resolution image from a set of low-resolution images. Many of superresolution techniques are designed for optical cameras, which produce pixel values of well-defined uncertainty, while there are still various imaging modalities for which the uncertainty of the images is difficult to control. To construct a superresolution image from low-resolution images with varying uncertainty, one needs to keep track of the uncertainty values in addition to the pixel values. In this paper, we develop a probabilistic approach to superresolution to address the problem of varying uncertainty. As direct computation of the analytic solution for the superresolution problem is difficult, we suggest a novel algorithm for computing the approximate solution. As this algorithm is a noniterative method based on Kalman filter-like recursion relations, there is a potential for real-time implementation of the algorithm. To show the efficiency of our method, we apply this algorithm to a video sequence acquired by a forward looking sonar system. © 2008 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 18, 242,250, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). [source] Imaging engineered tissues using structural and functional optical coherence tomographyJOURNAL OF BIOPHOTONICS, Issue 11 2009Xing Liang Abstract As the field of tissue engineering evolves, there will be an increasingly important need to visualize and track the complex dynamic changes that occur within three-dimensional constructs. Optical coherence tomography (OCT), as an emerging imaging technology applied to biological materials, offers a number of significant advantages to visualize these changes. Structural OCT has been used to investigate the longitudinal development of engineered tissues and cell dynamics such as migration, proliferation, detachment, and cell-material interactions. Optical techniques that image functional parameters or integrate multiple imaging modalities to provide complementary contrast mechanisms have been developed, such as the integration of optical coherence microscopy with multiphoton microscopy to image structural and functional information from cells in engineered tissue, optical coherence elastography to generate images or maps of strain to reflect the spatially-dependent biomechanical properties, and spectroscopic OCT to differentiate different cell types. From these results, OCT demonstrates great promise for imaging and visualizing engineered tissues, and the complex cellular dynamics that directly affect their practical and clinical use. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] In Vivo Determination of Bone Structure in Postmenopausal Women: A Comparison of HR-pQCT and High-Field MR Imaging,JOURNAL OF BONE AND MINERAL RESEARCH, Issue 4 2008Galateia J Kazakia PhD Abstract Bone structural measures obtained by two noninvasive imaging tools,3T MRI and HR-pQCT,were compared. Significant but moderate correlations and 2- to 4-fold discrepancies in parameter values were detected, suggesting that differences in acquisition and analysis must be considered when interpreting data from these imaging modalities. Introduction: High-field MRI and high resolution (HR)-pQCT are currently being used in longitudinal bone structure studies. Substantial differences in acquisition and analysis between these modalities may influence the quantitative data produced and could potentially influence clinical decisions based on their results. Our goal was to compare trabecular and cortical bone structural measures obtained in vivo by 3T MRI and HR-pQCT. Materials and Methods: Postmenopausal osteopenic women (n = 52) were recruited for this study. HR-pQCT imaging of the radius and tibia was performed using the XtremeCT scanner, with a voxel size of 82 × 82 × 82 ,m3. MR imaging was performed on a 3T Signa scanner using SSFP imaging sequences, with a pixel size of 156 × 156 ,m2 and slice thickness of 500 ,m. Structure parameters were calculated using standard HR-pQCT and MRI analysis techniques. Relationships between measures derived from HR-pQCT, MRI, and DXA were studied. Results: Significant correlations between HR-pQCT and MRI parameters were found (p < 0.0001) and were strongest for Tb.N (r2 = 0.52), Ct.Th (r2 = 0.59), and site-specific Tb.Sp (r2 = 0.54,0.60). MRI and HR-pQCT provided statistically different values of structure parameters (p < 0.0001), with BV/TV and Tb.Th exhibiting the largest discrepancies (MR/HR-pQCT = 3,4). Although differences in the Tb.N values were statistically significant, the mean differences were on the order of our reproducibility measurements. Systematic differences between MRI and HR-pQCT analysis procedures leading to discrepancies in cortical thickness values were observed, with MRI values consistently higher. Minimal correlations were found between MRI or HR-pQCT parameters and DXA BMD or T-score, except between HR-pQCT measures at the radius and the ultradistal radius T-scores, where moderate correlations were found (r2 = 0.19,0.58). Conclusions: This study provides unique insight into two emerging noninvasive tools for bone structure evaluation. Our findings highlight the significant influence of analysis technique on results of in vivo assessment and underscore the importance of accounting for these differences when interpreting results from these modalities. [source] | ||||||||||||||||||||||||||||||||||||||||