We report on two cases of patients with fat-equivalent masses in computed tomography(CT),referred to our department for dynamic positron emission tomography/CT(dPET/CT)with18F-fluorodeoxyglucose(18FFDG)in order to inv...We report on two cases of patients with fat-equivalent masses in computed tomography(CT),referred to our department for dynamic positron emission tomography/CT(dPET/CT)with18F-fluorodeoxyglucose(18FFDG)in order to investigate their dignity.Both qualitative and quantitative information,as derived from dPET/CTs,couldn’t exclude a high-grade liposarcoma:Visual evaluation,revealed a large hypermetabolic focus of intense18F-FDG uptake in each patient(average SUVs 8.3 and 11.3).Regression-based parametric imaging demonstrated an enhanced distribution volume,which correlates to perfusion,and a high phosphorylation rate that correlates to cell viability.Kinetic analysis,based on a two-tissue compartment model demonstrated an enhanced FDG transport k1and an enhanced phosphorylation rate k3.A non-compartmental approach based on fractal dimension revealed also enhanced values.However,final diagnosis was based on biopsy,which revealed hibernoma,a benign brown fat tumor.Brown adipose contains increased numbers of mitochondria and a high-rate of glucose metabolism.Therefore,they have increased FDG uptake.The evaluation of lipomatous lesions on CT,with high FDG uptake,should include the possibility of hibernoma as a differential diagnosis.展开更多
Understanding microcracking near coalesced fracture generation is critically important for hydrocarbon and geothermal reservoir characterization as well as damage evaluation in civil engineering structures. Dense and ...Understanding microcracking near coalesced fracture generation is critically important for hydrocarbon and geothermal reservoir characterization as well as damage evaluation in civil engineering structures. Dense and sometimes random microcracking near coalesced fracture formation alters the mechanical properties of the nearby virgin material. Individual microcrack characterization is also significant in quantifying the material changes near the fracture faces （i.e. damage）. Acoustic emission （AE） monitoring and analysis provide unique information regarding the microcracking process temporally, and infor- mation concerning the source characterization of individual microcracks can be extracted. In this context, laboratory hydraulic fracture tests were carried out while monitoring the AEs from several piezoelectric transducers. In-depth post-processing of the AE event data was performed for the purpose of under- standing the individual source mechanisms. Several source characterization techniques including moment tensor inversion, event parametric analysis, and volumetric deformation analysis were adopted. Post-test fracture characterization through coring, slicing and micro-computed tomographic imaging was performed to determine the coalesced fracture location and structure. Distinct differences in fracture characteristics were found spatially in relation to the openhole injection interval. Individual microcrack AE analysis showed substantial energy reduction emanating spatially from the injection interval. It was quantitatively observed that the recorded AE signals provided sufficient information to generalize the damage radiating spatially away from the injection wellbore.展开更多
Kidney transplantation is the best available treatment for patients with end stage renal disease. Despite the introduction of effective immunosuppressant drugs, episodes of acute allograft rejection still endanger gra...Kidney transplantation is the best available treatment for patients with end stage renal disease. Despite the introduction of effective immunosuppressant drugs, episodes of acute allograft rejection still endanger graft survival. Since efficient treatment of acute rejection is available, rapid diagnosis of this reversible graft injury is essential. For diagnosis of rejection, invasive core needle biopsy of the graft is the "gold-standard". However, biopsy carries the risk of significant graft injury and is not immediately feasible in patients taking anticoagulants. Therefore, a non-invasive tool assessing the whole organ for specific and fast detection of acute allograft rejection is desirable. We herein review current imaging-based state of the art approaches for non-invasive diagnostics of acute renal transplant rejection. We especially focus on new positron emission tomography-based as well as targeted ultrasoundbased methods.展开更多
Olfactory deficits on measures of identification, familiarity,and memory are consistently noted in patients with psychotic disorders relative to age-matched controls. Olfactory intensity ratings, however, appear to re...Olfactory deficits on measures of identification, familiarity,and memory are consistently noted in patients with psychotic disorders relative to age-matched controls. Olfactory intensity ratings, however, appear to remain intact while the data on hedonics and detection threshold are inconsistent. Despite the behavioral abnormalities noted, no specific regional brain hypoactivity has been identified in psychosis patients, for any of the olfactory domains. However, an intriguing finding emerged from this review in that the amygdala and pirifom cortices were not noted to be abnormal in hedonic processing(nor was the amygdala identified abnormal in any study) in psychotic disorders. This finding is in contrast to the literature in healthy individuals, in that this brain region is strongly implicated in olfactory processing(particularly for unpleasant odorants). Secondary olfactory cortex(orbitofrontal cortices, thalamus, and insula) was abnormally activated in the studies examined, particularly for hedonic processing. Further research, using consistent methodology, is required for better understanding the neurobiology of olfactory deficits. The authors suggest taking age and sex differences into consideration and further contrasting olfactory subgroups(impaired vs intact) to better our understanding of the heterogeneity of psychotic disorders.展开更多
Recent novel approaches in myocardial perfusion single photon emission CT(SPECT)have been facilitated by new dedicated high-effi ciency hardware with solid-state detectors and optimized collimators.New protocols inclu...Recent novel approaches in myocardial perfusion single photon emission CT(SPECT)have been facilitated by new dedicated high-effi ciency hardware with solid-state detectors and optimized collimators.New protocols include very low-dose(1 mSv)stress-only,two-position imaging to mitigate attenuation artifacts,and simultaneous dual-isotope imaging.Attenuation correction can be performed by specialized low-dose systems or by previously obtained CT coronary calcium scans.Hybrid protocols using CT angiography have been proposed.Image quality improvements have been demonstrated by novel reconstructions and motion correction.Fast SPECT acquisition facilitates dynamic fl ow and early function measurements.Image processing algorithms have become automated with virtually unsupervised extraction of quantitative imaging variables.This automation facilitates integration with clinical variables derived by machine learning to predict patient outcome or diagnosis.In this review,we describe new imaging protocols made possible by the new hardware developments.We also discuss several novel software approaches for the quantifi cation and interpretation of myocardial perfusion SPECT scans.展开更多
Positron emission tomography （PET） using 18F-fluorodeoxyglucose （FDG） has not been widely used in China for expensive cost （$1200）. Dual-head coincidence single photon emission computed tomography （DHC-SPECT） ...Positron emission tomography （PET） using 18F-fluorodeoxyglucose （FDG） has not been widely used in China for expensive cost （$1200）. Dual-head coincidence single photon emission computed tomography （DHC-SPECT） can depict many of the lesions depicted with a PET scanner in the lungs, which is used in place of PET-CT for discriminating malignant from benign pulmonary nodules in many studies. However, DHC-SPECT has inevitable false-negative results because the sensitivity for small lesions less than 2.0 cm is limited, and has high false-positive rate for active inflammatory nodules. Furthermore,DHC-SPECT also has a considerably higher cost （$300 in China） than other imaging examination.展开更多
AIM: To evaluate the functional differences between the 2 liver lobes in non-cirrhotic patients by using computed tomography/99mTc-galactosyl human serum albumin (CT/99mTc-GSA) single-photon emission computed tomograp...AIM: To evaluate the functional differences between the 2 liver lobes in non-cirrhotic patients by using computed tomography/99mTc-galactosyl human serum albumin (CT/99mTc-GSA) single-photon emission computed tomography (SPECT) fusion images. METHODS: Between December 2008 and March 2012, 264 non-cirrhotic patients underwent preoperative liver function assessment using CT/99mTc-GSA SPECT fusion images. Of these, 30 patients, in whom the influence of a tumor on the liver parenchyma was estimated to be negligible, were selected. Specifically, the selected patients were required to meet either of the following criteria: (1) the presence of an extrahepatic tumor; or (2) presence of a single small intrahepatic tumor. These 30 patients were retrospectively analyzed to calculate the percentage volume (%Volume) and the percentage function (%Function) of each lobe. The ratio between the %Function and %Volume (function-to-volume ratio) of each lobe was also calculated, and the ratios were compared between the 2 lobes. Furthermore, the correlations between the function-to-volume ratio and each of 2 liver parameters [lobe volume and diameter ratio of the left portal vein to the right portal vein (LPV-to-RPV diameter ratio)] were investigated. RESULTS: The median values of %Volume and %Function were 62.6% and 67.1% in the right lobe, with %Function being significantly higher than %Volume (P < 0.01). The median values of %Volume and %Function were 31.0% and 28.7% in the left lobe, with %Function being significantly lower than %Volume (P < 0.01). The function-to-volume ratios of the right lobe (1.04-1.14) were significantly higher than those of the left lobe (0.74-0.99) (P < 0.01). The function-to-volume ratio showed no significant correlation between the lobe volume in either lobe. In contrast, the function-to-volume ratio showed significant correlations with the LPV-to-RPV diameter ratio in both lobes (right lobe: negative correlation, rs = -0.37, P = 0.048; left lobe: positive correlation, r s = 0.71, P < 0.001). The function-to-volume ratio in the left lobe tended to be higher, and that in the right lobe tended to be lower, in accordance with the increase in the LPV-to-RPV diameter ratio. CONCLUSION: CT/99mTc-GSA SPECT fusion images demonstrated that the function of the left lobe was significantly decreased compared with that of the right lobe in non-cirrhotic livers.展开更多
Hypertension is currently one of the most prevalent il nesses worldwide,and is the second most common cause of heart failure,only behind ischemic cardiomyopathy.The development of novel multimodality imaging technique...Hypertension is currently one of the most prevalent il nesses worldwide,and is the second most common cause of heart failure,only behind ischemic cardiomyopathy.The development of novel multimodality imaging techniques in recent years has broadened the diagnostic methods,risk stratification and monitoring of treatment of cardiovascular diseases available for clinicians.Cardiovascular magnetic resonance(CMR) has a great capacity to evaluate cardiac dimensions and ventricular function,is extremely useful in ruling-out ischemic cardiomyopathy,the evaluation of the vascular system,in making the differential diagnosis for resistant hypertension and risk stratification for hypertensive cardiomyopathy and constitutes today,the method of choice to evaluate left ventricular systolic function.Computed tomography(CT) is the method of choice for the evaluation of vascular anatomy,including coronary arteries,and is also able to provide both functional and structural information.Finally,nuclear cardiology studies have been traditionally used to evaluate myocardial ischemia,along with offering the capacity to evaluate ventricular,endothelial and cardiac innervation function;information that is key in directing the treatment of the patient.In this narrative review,the most recent contributions of multimodality imaging to the patient with hypertension(CMR,CT and nuclear cardiology) will be reviewed.展开更多
Infective endocarditis is one of the leading life-threatening infections around the world.With the exponential growth in the field of transcatheter interventions and advances in specialized surgical techniques,the num...Infective endocarditis is one of the leading life-threatening infections around the world.With the exponential growth in the field of transcatheter interventions and advances in specialized surgical techniques,the number of prosthetic valves and cardiac implantable devices has significantly increased.This has led to a steep rise in the number of cases of prosthetic valve endocarditis(PVE)comprising up to 30%of all cases.Clinical guidelines rely on the use of the modified Duke criteria;however,the diagnostic sensitivity of the modified Duke criteria is reduced in the context of PVE.This is in part attributed to prosthesis related artifact which greatly affects the ability of echocardiography to detect early infective changes related to PVE in certain cases.There has been increasing recognition of the roles of complementary imaging modalities and updates in international society recommendations.Prompt diagnosis and treatment can prevent the devastating consequences of this condition.Imaging modalities such as cardiac computed tomography and 18-fluorodeoxyglucose positron emission tomography/computed tomography are diagnostic tools that provide a complementary role to echocardiography in aiding diagnosis,pre-operative planning,and treatment decisionmaking process in these challenging cases.Understanding the strengths and limitations of these adjuvant imaging modalities is crucial for the implementation of appropriate imaging modalities in clinical practice.展开更多
文摘We report on two cases of patients with fat-equivalent masses in computed tomography(CT),referred to our department for dynamic positron emission tomography/CT(dPET/CT)with18F-fluorodeoxyglucose(18FFDG)in order to investigate their dignity.Both qualitative and quantitative information,as derived from dPET/CTs,couldn’t exclude a high-grade liposarcoma:Visual evaluation,revealed a large hypermetabolic focus of intense18F-FDG uptake in each patient(average SUVs 8.3 and 11.3).Regression-based parametric imaging demonstrated an enhanced distribution volume,which correlates to perfusion,and a high phosphorylation rate that correlates to cell viability.Kinetic analysis,based on a two-tissue compartment model demonstrated an enhanced FDG transport k1and an enhanced phosphorylation rate k3.A non-compartmental approach based on fractal dimension revealed also enhanced values.However,final diagnosis was based on biopsy,which revealed hibernoma,a benign brown fat tumor.Brown adipose contains increased numbers of mitochondria and a high-rate of glucose metabolism.Therefore,they have increased FDG uptake.The evaluation of lipomatous lesions on CT,with high FDG uptake,should include the possibility of hibernoma as a differential diagnosis.
基金financial support for much of the early development of the AE analysis methods was provided by the U.S. Department of Energy (DOE) (Grant No. DE-FE0002760)
文摘Understanding microcracking near coalesced fracture generation is critically important for hydrocarbon and geothermal reservoir characterization as well as damage evaluation in civil engineering structures. Dense and sometimes random microcracking near coalesced fracture formation alters the mechanical properties of the nearby virgin material. Individual microcrack characterization is also significant in quantifying the material changes near the fracture faces （i.e. damage）. Acoustic emission （AE） monitoring and analysis provide unique information regarding the microcracking process temporally, and infor- mation concerning the source characterization of individual microcracks can be extracted. In this context, laboratory hydraulic fracture tests were carried out while monitoring the AEs from several piezoelectric transducers. In-depth post-processing of the AE event data was performed for the purpose of under- standing the individual source mechanisms. Several source characterization techniques including moment tensor inversion, event parametric analysis, and volumetric deformation analysis were adopted. Post-test fracture characterization through coring, slicing and micro-computed tomographic imaging was performed to determine the coalesced fracture location and structure. Distinct differences in fracture characteristics were found spatially in relation to the openhole injection interval. Individual microcrack AE analysis showed substantial energy reduction emanating spatially from the injection interval. It was quantitatively observed that the recorded AE signals provided sufficient information to generalize the damage radiating spatially away from the injection wellbore.
基金Supported by The Collaborative Research Centre 656(Deutsche Forschungsgemeinschaft,SFB656,Projects C7 and PM12 and 21)Innovative Medizinische Forschung,Medical Faculty,University of Münster,No.IRE121102
文摘Kidney transplantation is the best available treatment for patients with end stage renal disease. Despite the introduction of effective immunosuppressant drugs, episodes of acute allograft rejection still endanger graft survival. Since efficient treatment of acute rejection is available, rapid diagnosis of this reversible graft injury is essential. For diagnosis of rejection, invasive core needle biopsy of the graft is the "gold-standard". However, biopsy carries the risk of significant graft injury and is not immediately feasible in patients taking anticoagulants. Therefore, a non-invasive tool assessing the whole organ for specific and fast detection of acute allograft rejection is desirable. We herein review current imaging-based state of the art approaches for non-invasive diagnostics of acute renal transplant rejection. We especially focus on new positron emission tomography-based as well as targeted ultrasoundbased methods.
基金Supported by In part the Department of Psychiatry Dalhousie UniversityThe Faculty of Medicine at Dalhousie University+1 种基金The Nova Scotia Health Research Fundthe Canadian Institutes of Health Research
文摘Olfactory deficits on measures of identification, familiarity,and memory are consistently noted in patients with psychotic disorders relative to age-matched controls. Olfactory intensity ratings, however, appear to remain intact while the data on hedonics and detection threshold are inconsistent. Despite the behavioral abnormalities noted, no specific regional brain hypoactivity has been identified in psychosis patients, for any of the olfactory domains. However, an intriguing finding emerged from this review in that the amygdala and pirifom cortices were not noted to be abnormal in hedonic processing(nor was the amygdala identified abnormal in any study) in psychotic disorders. This finding is in contrast to the literature in healthy individuals, in that this brain region is strongly implicated in olfactory processing(particularly for unpleasant odorants). Secondary olfactory cortex(orbitofrontal cortices, thalamus, and insula) was abnormally activated in the studies examined, particularly for hedonic processing. Further research, using consistent methodology, is required for better understanding the neurobiology of olfactory deficits. The authors suggest taking age and sex differences into consideration and further contrasting olfactory subgroups(impaired vs intact) to better our understanding of the heterogeneity of psychotic disorders.
文摘Recent novel approaches in myocardial perfusion single photon emission CT(SPECT)have been facilitated by new dedicated high-effi ciency hardware with solid-state detectors and optimized collimators.New protocols include very low-dose(1 mSv)stress-only,two-position imaging to mitigate attenuation artifacts,and simultaneous dual-isotope imaging.Attenuation correction can be performed by specialized low-dose systems or by previously obtained CT coronary calcium scans.Hybrid protocols using CT angiography have been proposed.Image quality improvements have been demonstrated by novel reconstructions and motion correction.Fast SPECT acquisition facilitates dynamic fl ow and early function measurements.Image processing algorithms have become automated with virtually unsupervised extraction of quantitative imaging variables.This automation facilitates integration with clinical variables derived by machine learning to predict patient outcome or diagnosis.In this review,we describe new imaging protocols made possible by the new hardware developments.We also discuss several novel software approaches for the quantifi cation and interpretation of myocardial perfusion SPECT scans.
文摘Positron emission tomography （PET） using 18F-fluorodeoxyglucose （FDG） has not been widely used in China for expensive cost （$1200）. Dual-head coincidence single photon emission computed tomography （DHC-SPECT） can depict many of the lesions depicted with a PET scanner in the lungs, which is used in place of PET-CT for discriminating malignant from benign pulmonary nodules in many studies. However, DHC-SPECT has inevitable false-negative results because the sensitivity for small lesions less than 2.0 cm is limited, and has high false-positive rate for active inflammatory nodules. Furthermore,DHC-SPECT also has a considerably higher cost （$300 in China） than other imaging examination.
文摘AIM: To evaluate the functional differences between the 2 liver lobes in non-cirrhotic patients by using computed tomography/99mTc-galactosyl human serum albumin (CT/99mTc-GSA) single-photon emission computed tomography (SPECT) fusion images. METHODS: Between December 2008 and March 2012, 264 non-cirrhotic patients underwent preoperative liver function assessment using CT/99mTc-GSA SPECT fusion images. Of these, 30 patients, in whom the influence of a tumor on the liver parenchyma was estimated to be negligible, were selected. Specifically, the selected patients were required to meet either of the following criteria: (1) the presence of an extrahepatic tumor; or (2) presence of a single small intrahepatic tumor. These 30 patients were retrospectively analyzed to calculate the percentage volume (%Volume) and the percentage function (%Function) of each lobe. The ratio between the %Function and %Volume (function-to-volume ratio) of each lobe was also calculated, and the ratios were compared between the 2 lobes. Furthermore, the correlations between the function-to-volume ratio and each of 2 liver parameters [lobe volume and diameter ratio of the left portal vein to the right portal vein (LPV-to-RPV diameter ratio)] were investigated. RESULTS: The median values of %Volume and %Function were 62.6% and 67.1% in the right lobe, with %Function being significantly higher than %Volume (P < 0.01). The median values of %Volume and %Function were 31.0% and 28.7% in the left lobe, with %Function being significantly lower than %Volume (P < 0.01). The function-to-volume ratios of the right lobe (1.04-1.14) were significantly higher than those of the left lobe (0.74-0.99) (P < 0.01). The function-to-volume ratio showed no significant correlation between the lobe volume in either lobe. In contrast, the function-to-volume ratio showed significant correlations with the LPV-to-RPV diameter ratio in both lobes (right lobe: negative correlation, rs = -0.37, P = 0.048; left lobe: positive correlation, r s = 0.71, P < 0.001). The function-to-volume ratio in the left lobe tended to be higher, and that in the right lobe tended to be lower, in accordance with the increase in the LPV-to-RPV diameter ratio. CONCLUSION: CT/99mTc-GSA SPECT fusion images demonstrated that the function of the left lobe was significantly decreased compared with that of the right lobe in non-cirrhotic livers.
文摘Hypertension is currently one of the most prevalent il nesses worldwide,and is the second most common cause of heart failure,only behind ischemic cardiomyopathy.The development of novel multimodality imaging techniques in recent years has broadened the diagnostic methods,risk stratification and monitoring of treatment of cardiovascular diseases available for clinicians.Cardiovascular magnetic resonance(CMR) has a great capacity to evaluate cardiac dimensions and ventricular function,is extremely useful in ruling-out ischemic cardiomyopathy,the evaluation of the vascular system,in making the differential diagnosis for resistant hypertension and risk stratification for hypertensive cardiomyopathy and constitutes today,the method of choice to evaluate left ventricular systolic function.Computed tomography(CT) is the method of choice for the evaluation of vascular anatomy,including coronary arteries,and is also able to provide both functional and structural information.Finally,nuclear cardiology studies have been traditionally used to evaluate myocardial ischemia,along with offering the capacity to evaluate ventricular,endothelial and cardiac innervation function;information that is key in directing the treatment of the patient.In this narrative review,the most recent contributions of multimodality imaging to the patient with hypertension(CMR,CT and nuclear cardiology) will be reviewed.
文摘Infective endocarditis is one of the leading life-threatening infections around the world.With the exponential growth in the field of transcatheter interventions and advances in specialized surgical techniques,the number of prosthetic valves and cardiac implantable devices has significantly increased.This has led to a steep rise in the number of cases of prosthetic valve endocarditis(PVE)comprising up to 30%of all cases.Clinical guidelines rely on the use of the modified Duke criteria;however,the diagnostic sensitivity of the modified Duke criteria is reduced in the context of PVE.This is in part attributed to prosthesis related artifact which greatly affects the ability of echocardiography to detect early infective changes related to PVE in certain cases.There has been increasing recognition of the roles of complementary imaging modalities and updates in international society recommendations.Prompt diagnosis and treatment can prevent the devastating consequences of this condition.Imaging modalities such as cardiac computed tomography and 18-fluorodeoxyglucose positron emission tomography/computed tomography are diagnostic tools that provide a complementary role to echocardiography in aiding diagnosis,pre-operative planning,and treatment decisionmaking process in these challenging cases.Understanding the strengths and limitations of these adjuvant imaging modalities is crucial for the implementation of appropriate imaging modalities in clinical practice.
