To minimize radiation risk,dose reduction is important in the diagnostic and therapeutic applications of computed tomography(CT).However,image noise degrades image quality owing to the reduced X-ray dose and a possibl...To minimize radiation risk,dose reduction is important in the diagnostic and therapeutic applications of computed tomography(CT).However,image noise degrades image quality owing to the reduced X-ray dose and a possible unacceptably reduced diagnostic performance.Deep learning approaches with convolutional neural networks(CNNs)have been proposed for natural image denoising;however,these approaches might introduce image blurring or loss of original gradients.The aim of this study was to compare the dose-dependent properties of a CNN-based denoising method for low-dose CT with those of other noise-reduction methods on unique CT noise-simulation images.To simulate a low-dose CT image,a Poisson noise distribution was introduced to normal-dose images while convoluting the CT unit-specific modulation transfer function.An abdominal CT of 100 images obtained from a public database was adopted,and simulated dose-reduction images were created from the original dose at equal 10-step dose-reduction intervals with a final dose of 1/100.These images were denoised using the denoising network structure of CNN(DnCNN)as the general CNN model and for transfer learning.To evaluate the image quality,image similarities determined by the structural similarity index(SSIM)and peak signal-to-noise ratio(PSNR)were calculated for the denoised images.Significantly better denoising,in terms of SSIM and PSNR,was achieved by the DnCNN than by other image denoising methods,especially at the ultra-low-dose levels used to generate the 10%and 5%dose-equivalent images.Moreover,the developed CNN model can eliminate noise and maintain image sharpness at these dose levels and improve SSIM by approximately 10%from that of the original method.In contrast,under small dose-reduction conditions,this model also led to excessive smoothing of the images.In quantitative evaluations,the CNN denoising method improved the low-dose CT and prevented over-smoothing by tailoring the CNN model.展开更多
AIM To compare radiation dose and image quality of lowdose computed tomography(CT) protocol combined with hybrid-iterative reconstruction algorithm with standarddose CT examinations for follow-up of oncologic patients...AIM To compare radiation dose and image quality of lowdose computed tomography(CT) protocol combined with hybrid-iterative reconstruction algorithm with standarddose CT examinations for follow-up of oncologic patients. METHODS Fifty-one patients with known malignant diseases which underwent, during clinical follow-up, both standarddose and low-dose whole-body CT scans were enrolled. Low-dose CT was performed on 256-row scanner, with 120 kV and automated m A modulation, and iterative reconstruction algorithm. Standard-dose CT was performed on 16-rows scanner, with 120 kV, 200-400 m As(depending on patient weight). We evaluated density values and signal-to-noise ratio, along with image noise(SD), sharpness and diagnostic quality with 4-point scale.RESULTS Density values in liver, spleen and aorta were higher in lowdose images(liver 112.55 HU vs 103.90 HU, P < 0.001), as SD values in liver and spleen(liver 16.81 vs 14.41). Volumetric-Computed-Tomographic-Dose-Index(CTDIvol) and Dose-Length-Product(DLP) were significantly lower in low-dose CT as compared to standard-dose(DLP 1025.6 m Gy*cm vs 1429.2 m Gy*cm, P < 0.001) with overall dose reduction of 28.9%. Qualitative analysis did not reveal significant differences in image noise and diagnostic quality.CONCLUSION Automatic tube-current modulation combined with hybriditerative algorithm allows radiation dose reduction of 28.9% without loss of diagnostic quality, being useful in reducing dose exposure in oncologic patients.展开更多
BACKGROUND Accurate delineation of the target area for patients with hypopharyngeal cancer is the key to achieving an ideal radiotherapy effect.Since computed tomography(CT)alone can no longer meet the treatment needs...BACKGROUND Accurate delineation of the target area for patients with hypopharyngeal cancer is the key to achieving an ideal radiotherapy effect.Since computed tomography(CT)alone can no longer meet the treatment needs,fusing CT images with magnetic resonance imaging(MRI)or positron emission tomography(PET)images can overcome the disadvantages of CT.Herein,we present a clinical case of hypopharyngeal cancer to delineate the tumor volume using combined MRI-CT and PET-CT fusion images to examine if they could accurately cover the tumor volume.CASE SUMMARY A 67-year-old male patient with hypopharyngeal carcinoma could not tolerate chemotherapy and surgery due to complicated health issues such as diabetic nephropathy and other underlying diseases.After multidisciplinary consultations,clinicians eventually agreed to undergo radiotherapy to control the progression of his tumor.He was examined by CT,MRI,and 18-fluorodeoxyglucose-PET for treatment planning,and CT images were fused with PET and MRI images while delineating tumor volume.CONCLUSION The image fusion of MRI-CT and PET-CT has both advantages and disadvantages.Compared with CT images alone,the combination of MRI-CT and PET-CT fusion images can precisely cover the gross tumor volume in hypopharyngeal carcinoma and avoid overestimation or incomplete coverage of tumor volume.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
Objective To explore the efficacy of target positioning by preoperative CT/MRI image fusion technique in deep brain stimulation.Methods We retrospectively analyzed the clinical data and images of 79 cases(68 with Park...Objective To explore the efficacy of target positioning by preoperative CT/MRI image fusion technique in deep brain stimulation.Methods We retrospectively analyzed the clinical data and images of 79 cases(68 with Parkinson's disease,11 with dystonia) who received preoperative CT/MRI image fusion in target positioning of subthalamic nucleus in deep brain stimulation.Deviation of implanted electrodes from the target nucleus of each patient were measured.Neurological evaluations of each patient before and after the treatment were performed and compared.Complications of the positioning and treatment were recorded.Results The mean deviations of the electrodes implanted on X,Y,and Z axis were 0.5 mm,0.6 mm,and 0.6 mm,respectively.Postoperative neurologic evaluations scores of unified Parkinson's disease rating scale(UPDRS) for Parkinson's disease and Burke-Fahn-Marsden Dystonia Rating Scale(BFMDRS) for dystonia patients improved significantly compared to the preoperative scores(P<0.001); Complications occurred in 10.1%(8/79) patients,and main side effects were dysarthria and diplopia.Conclusion Target positioning by preoperative CT/MRI image fusion technique in deep brain stimulation has high accuracy and good clinical outcomes.展开更多
Coronary artery disease （CAD） is one of the leading causes of death in the US and a substantial health-care burden in all industrialized societies. In recent years we have witnessed a constant strive towards the dev...Coronary artery disease （CAD） is one of the leading causes of death in the US and a substantial health-care burden in all industrialized societies. In recent years we have witnessed a constant strive towards the development and the clinical application of novel or improved detection methods as well as therapies. Particularly, noninvasive imaging is a decisive component in the cardiovascular field. Image fusion is the ability of combining into a sin- gle integrated display the anatomical as well as the physiological data retrieved by separated modalities. Clinical evidence suggests that it represents a promising strategy in CAD assessment and risk stratification by significantly improving the diagnostic power of each modality independently considered and of the traditional side-by-side in- terpretation. Numerous techniques and approaches taken from the image registration field have been implemented and validated in the context of CAD assessment and management. Although its diagnostic power is widely ac- cepted, additional technical developments are still needed to become a routinely used clinical tool.展开更多
The preliminary studies of the multimodality image registration and fusion were performed using an image fusion software and a picture archiving and communication system (PACS) to explore the methodology. Original ima...The preliminary studies of the multimodality image registration and fusion were performed using an image fusion software and a picture archiving and communication system (PACS) to explore the methodology. Original image voluminal data were acquired with a CT scanner, MR and dual-head coincidence SPECT, respectively. The data sets from all imaging devices were queried, retrieved, transferred and accessed via DICOM PACS. The image fusion was performed at the SPECT ICON work-station, where the MIM (Medical Image Merge) fusion software was installed. The images were created by reslicing original volume on the fly. The image volumes were aligned by translation and rotation of these view ports with respect to the original volume orientation. The transparency factor and contrast were adjusted in order that both volumes can be visualized in the merged images. The image volume data of CT, MR and nuclear medicine were transferred, accessed and loaded via PACS successfully. The perfect fused images of chest CT/18F-FDG and brain MR/SPECT were obtained. These results showed that image fusion technique using PACS was feasible and practical. Further experimentation and larger validation studies were needed to explore the full potential of the clinical use.展开更多
Objective. To compare and match metabolic images of PET with anatomic images of CT and MRI. Methods. The CT or MRI images of the patients were obtained through a photo scanner, and then transferred to the remote works...Objective. To compare and match metabolic images of PET with anatomic images of CT and MRI. Methods. The CT or MRI images of the patients were obtained through a photo scanner, and then transferred to the remote workstation of PET scanner with a floppy disk. A fusion method was developed to match the 2- dimensional CT or MRI slices with the correlative slices of 3- dimensional volume PET images. Results. Twenty－ nine metabolically changed foci were accurately localized in 21 epilepsy patients’ MRI images, while MRI alone had only 6 true positive findings. In 53 cancer or suspicious cancer patients, 53 positive lesions detected by PET were compared and matched with the corresponding lesions in CT or MRI images, in which 10 lesions were missed. On the other hand, 23 lesions detected from the patients’ CT or MRI images were negative or with low uptake in the PET images, and they were finally proved as benign. Conclusions. Comparing and matching metabolic images with anatomic images helped obtain a full understanding about the lesion and its peripheral structures. The fusion method was simple, practical and useful for localizing metabolically changed lesions.展开更多
Background:Noncontrast computed tomography(CT)scan of the kidneys,ureter and bladder is the standard investigative modality for diagnosing and following up patients with urolithiasis.With each scan,a patient receives ...Background:Noncontrast computed tomography(CT)scan of the kidneys,ureter and bladder is the standard investigative modality for diagnosing and following up patients with urolithiasis.With each scan,a patient receives radiation of 18-34 mGy.Dose considerations become pertinent because of a 10%lifetime incidence rate and higher than 50%risk of recurrence,necessitating repeated imaging in the lifetime of a stone former.Hence,this study aimed to assess the sensitivity of"reduced-radiation"CT imaging by altering scan settings to lower than the"standard"norms.Materials and methods:Altogether,222 patients(255"kidney-ureter"stone-bearing units or"renal units")with urolithiasis and patients undergoing CT for other reasons with incidental findings of renal/ureteric calculi between 2017 and 2019 were included.All patients were subjected to 3 sequential scans at tube current settings of 250 mA(CT-N/Standard),100 mA(CT-100),and 50 mA(CT-50)at a constant voltage of 120 kV.Their clinicodemographic and radiological findings were recorded and assessed for significance.Results:Of the 255 renal units,117 were between 30 and 44 years of age,75%were men.Of the 255 patients,178(70.1%)reported a first stone episode and 77 had recurrence.Lower ureteric calculi were predominant(40.4%).All calculi were identified on CT-N;CT-100 failed to detect calculi in 1 patient,and CT-50 failed in 3 patients,where all calculi were<3 mm in size.Meanwhile,none were undetected among patients with obesity.The sensitivity was 99.61%for the CT-100 and 98.82%for the CT-50,which indicated a 2.5 and 5 times lower radiation and dose/length,respectively,than CT-N.Conclusions:The reduced-radiation CT scan is safe,sensitive,and accurate for the diagnosis and follow-up of patients with urolithiasis with significantly lower radiation exposures.Our study lays the foundation to accept low-dose CT in general and CT-50 in particular,as the new"standard of care,"and attempt further dose reduction without loss of diagnostic efficacy.展开更多
Aim:The present study was designed to evaluate the feasibility of preoperative liver functional volumetry performed by 3D-technetium-99m-diethylenetriaminepentaacetic acid-galactosyl-human serum albumin(99mTc-GSA)scin...Aim:The present study was designed to evaluate the feasibility of preoperative liver functional volumetry performed by 3D-technetium-99m-diethylenetriaminepentaacetic acid-galactosyl-human serum albumin(99mTc-GSA)scintigraphy/vascular fusion imaging using SYNAPSE VINCENT and to examine the discrepancy between conventional and functional volumetry.Methods:The study group comprised 15 patients who underwent preoperative 3-dimensional(3D)-99mTc-GSA scintigraphy/vascular fusion imaging using SYNAPSE VINCENT software before hepatectomy between July 2014 and August 2015.The diagnosis was hepatocellular carcinoma(n=4),metastatic liver tumor(n=10),or intrahepatic cholangiocarcinoma(n=1).Right hepatectomy was performed in 2 patients,left hepatectomy in 3 patients,right posterior sectionectomy in 3 patients,segmentectomy in 2 patients,and partial hepatectomy in 4 patients.99mTc-GSA scintigraphy and computed tomography(CT)were performed to construct 3D-99mTc-GSA scintigraphy/vascular fused images.The conventional volume ratio of the planned resection region without tumor(%CT),and the functional volume ratio of the planned resection region without tumor(%GSA)were calculated.The discrepancy ratio was calculated as follows:discrepancy ratio=100-%GSA/%CT×100(%).Results:The%GSA(17.9±16.7%)was significantly lower than the%CT(21.5±17.6%)(P<0.036).In all except 2 patients,the%GSA was lower than the%CT.The discrepancy ratio ranged from-4%to 75%(median,20.7%).Conclusion:3D-99mTc-GSA scintigraphy/vascular fused images constructed using SYNAPSE VINCENT were useful for noninvasively performing functional liver volumetry in patients scheduled to undergo various patterns of hepatectomy.In planned resection regions without tumor,the functional volume ratio was about 20%lower than the conventional volume ratio.展开更多
基金This work was supported by JSPS KAKENHI,No.18 K15563.
文摘To minimize radiation risk,dose reduction is important in the diagnostic and therapeutic applications of computed tomography(CT).However,image noise degrades image quality owing to the reduced X-ray dose and a possible unacceptably reduced diagnostic performance.Deep learning approaches with convolutional neural networks(CNNs)have been proposed for natural image denoising;however,these approaches might introduce image blurring or loss of original gradients.The aim of this study was to compare the dose-dependent properties of a CNN-based denoising method for low-dose CT with those of other noise-reduction methods on unique CT noise-simulation images.To simulate a low-dose CT image,a Poisson noise distribution was introduced to normal-dose images while convoluting the CT unit-specific modulation transfer function.An abdominal CT of 100 images obtained from a public database was adopted,and simulated dose-reduction images were created from the original dose at equal 10-step dose-reduction intervals with a final dose of 1/100.These images were denoised using the denoising network structure of CNN(DnCNN)as the general CNN model and for transfer learning.To evaluate the image quality,image similarities determined by the structural similarity index(SSIM)and peak signal-to-noise ratio(PSNR)were calculated for the denoised images.Significantly better denoising,in terms of SSIM and PSNR,was achieved by the DnCNN than by other image denoising methods,especially at the ultra-low-dose levels used to generate the 10%and 5%dose-equivalent images.Moreover,the developed CNN model can eliminate noise and maintain image sharpness at these dose levels and improve SSIM by approximately 10%from that of the original method.In contrast,under small dose-reduction conditions,this model also led to excessive smoothing of the images.In quantitative evaluations,the CNN denoising method improved the low-dose CT and prevented over-smoothing by tailoring the CNN model.
文摘AIM To compare radiation dose and image quality of lowdose computed tomography(CT) protocol combined with hybrid-iterative reconstruction algorithm with standarddose CT examinations for follow-up of oncologic patients. METHODS Fifty-one patients with known malignant diseases which underwent, during clinical follow-up, both standarddose and low-dose whole-body CT scans were enrolled. Low-dose CT was performed on 256-row scanner, with 120 kV and automated m A modulation, and iterative reconstruction algorithm. Standard-dose CT was performed on 16-rows scanner, with 120 kV, 200-400 m As(depending on patient weight). We evaluated density values and signal-to-noise ratio, along with image noise(SD), sharpness and diagnostic quality with 4-point scale.RESULTS Density values in liver, spleen and aorta were higher in lowdose images(liver 112.55 HU vs 103.90 HU, P < 0.001), as SD values in liver and spleen(liver 16.81 vs 14.41). Volumetric-Computed-Tomographic-Dose-Index(CTDIvol) and Dose-Length-Product(DLP) were significantly lower in low-dose CT as compared to standard-dose(DLP 1025.6 m Gy*cm vs 1429.2 m Gy*cm, P < 0.001) with overall dose reduction of 28.9%. Qualitative analysis did not reveal significant differences in image noise and diagnostic quality.CONCLUSION Automatic tube-current modulation combined with hybriditerative algorithm allows radiation dose reduction of 28.9% without loss of diagnostic quality, being useful in reducing dose exposure in oncologic patients.
文摘BACKGROUND Accurate delineation of the target area for patients with hypopharyngeal cancer is the key to achieving an ideal radiotherapy effect.Since computed tomography(CT)alone can no longer meet the treatment needs,fusing CT images with magnetic resonance imaging(MRI)or positron emission tomography(PET)images can overcome the disadvantages of CT.Herein,we present a clinical case of hypopharyngeal cancer to delineate the tumor volume using combined MRI-CT and PET-CT fusion images to examine if they could accurately cover the tumor volume.CASE SUMMARY A 67-year-old male patient with hypopharyngeal carcinoma could not tolerate chemotherapy and surgery due to complicated health issues such as diabetic nephropathy and other underlying diseases.After multidisciplinary consultations,clinicians eventually agreed to undergo radiotherapy to control the progression of his tumor.He was examined by CT,MRI,and 18-fluorodeoxyglucose-PET for treatment planning,and CT images were fused with PET and MRI images while delineating tumor volume.CONCLUSION The image fusion of MRI-CT and PET-CT has both advantages and disadvantages.Compared with CT images alone,the combination of MRI-CT and PET-CT fusion images can precisely cover the gross tumor volume in hypopharyngeal carcinoma and avoid overestimation or incomplete coverage of tumor volume.
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Objective To explore the efficacy of target positioning by preoperative CT/MRI image fusion technique in deep brain stimulation.Methods We retrospectively analyzed the clinical data and images of 79 cases(68 with Parkinson's disease,11 with dystonia) who received preoperative CT/MRI image fusion in target positioning of subthalamic nucleus in deep brain stimulation.Deviation of implanted electrodes from the target nucleus of each patient were measured.Neurological evaluations of each patient before and after the treatment were performed and compared.Complications of the positioning and treatment were recorded.Results The mean deviations of the electrodes implanted on X,Y,and Z axis were 0.5 mm,0.6 mm,and 0.6 mm,respectively.Postoperative neurologic evaluations scores of unified Parkinson's disease rating scale(UPDRS) for Parkinson's disease and Burke-Fahn-Marsden Dystonia Rating Scale(BFMDRS) for dystonia patients improved significantly compared to the preoperative scores(P<0.001); Complications occurred in 10.1%(8/79) patients,and main side effects were dysarthria and diplopia.Conclusion Target positioning by preoperative CT/MRI image fusion technique in deep brain stimulation has high accuracy and good clinical outcomes.
文摘Coronary artery disease （CAD） is one of the leading causes of death in the US and a substantial health-care burden in all industrialized societies. In recent years we have witnessed a constant strive towards the development and the clinical application of novel or improved detection methods as well as therapies. Particularly, noninvasive imaging is a decisive component in the cardiovascular field. Image fusion is the ability of combining into a sin- gle integrated display the anatomical as well as the physiological data retrieved by separated modalities. Clinical evidence suggests that it represents a promising strategy in CAD assessment and risk stratification by significantly improving the diagnostic power of each modality independently considered and of the traditional side-by-side in- terpretation. Numerous techniques and approaches taken from the image registration field have been implemented and validated in the context of CAD assessment and management. Although its diagnostic power is widely ac- cepted, additional technical developments are still needed to become a routinely used clinical tool.
文摘The preliminary studies of the multimodality image registration and fusion were performed using an image fusion software and a picture archiving and communication system (PACS) to explore the methodology. Original image voluminal data were acquired with a CT scanner, MR and dual-head coincidence SPECT, respectively. The data sets from all imaging devices were queried, retrieved, transferred and accessed via DICOM PACS. The image fusion was performed at the SPECT ICON work-station, where the MIM (Medical Image Merge) fusion software was installed. The images were created by reslicing original volume on the fly. The image volumes were aligned by translation and rotation of these view ports with respect to the original volume orientation. The transparency factor and contrast were adjusted in order that both volumes can be visualized in the merged images. The image volume data of CT, MR and nuclear medicine were transferred, accessed and loaded via PACS successfully. The perfect fused images of chest CT/18F-FDG and brain MR/SPECT were obtained. These results showed that image fusion technique using PACS was feasible and practical. Further experimentation and larger validation studies were needed to explore the full potential of the clinical use.
文摘Objective. To compare and match metabolic images of PET with anatomic images of CT and MRI. Methods. The CT or MRI images of the patients were obtained through a photo scanner, and then transferred to the remote workstation of PET scanner with a floppy disk. A fusion method was developed to match the 2- dimensional CT or MRI slices with the correlative slices of 3- dimensional volume PET images. Results. Twenty－ nine metabolically changed foci were accurately localized in 21 epilepsy patients’ MRI images, while MRI alone had only 6 true positive findings. In 53 cancer or suspicious cancer patients, 53 positive lesions detected by PET were compared and matched with the corresponding lesions in CT or MRI images, in which 10 lesions were missed. On the other hand, 23 lesions detected from the patients’ CT or MRI images were negative or with low uptake in the PET images, and they were finally proved as benign. Conclusions. Comparing and matching metabolic images with anatomic images helped obtain a full understanding about the lesion and its peripheral structures. The fusion method was simple, practical and useful for localizing metabolically changed lesions.
文摘Background:Noncontrast computed tomography(CT)scan of the kidneys,ureter and bladder is the standard investigative modality for diagnosing and following up patients with urolithiasis.With each scan,a patient receives radiation of 18-34 mGy.Dose considerations become pertinent because of a 10%lifetime incidence rate and higher than 50%risk of recurrence,necessitating repeated imaging in the lifetime of a stone former.Hence,this study aimed to assess the sensitivity of"reduced-radiation"CT imaging by altering scan settings to lower than the"standard"norms.Materials and methods:Altogether,222 patients(255"kidney-ureter"stone-bearing units or"renal units")with urolithiasis and patients undergoing CT for other reasons with incidental findings of renal/ureteric calculi between 2017 and 2019 were included.All patients were subjected to 3 sequential scans at tube current settings of 250 mA(CT-N/Standard),100 mA(CT-100),and 50 mA(CT-50)at a constant voltage of 120 kV.Their clinicodemographic and radiological findings were recorded and assessed for significance.Results:Of the 255 renal units,117 were between 30 and 44 years of age,75%were men.Of the 255 patients,178(70.1%)reported a first stone episode and 77 had recurrence.Lower ureteric calculi were predominant(40.4%).All calculi were identified on CT-N;CT-100 failed to detect calculi in 1 patient,and CT-50 failed in 3 patients,where all calculi were<3 mm in size.Meanwhile,none were undetected among patients with obesity.The sensitivity was 99.61%for the CT-100 and 98.82%for the CT-50,which indicated a 2.5 and 5 times lower radiation and dose/length,respectively,than CT-N.Conclusions:The reduced-radiation CT scan is safe,sensitive,and accurate for the diagnosis and follow-up of patients with urolithiasis with significantly lower radiation exposures.Our study lays the foundation to accept low-dose CT in general and CT-50 in particular,as the new"standard of care,"and attempt further dose reduction without loss of diagnostic efficacy.
文摘Aim:The present study was designed to evaluate the feasibility of preoperative liver functional volumetry performed by 3D-technetium-99m-diethylenetriaminepentaacetic acid-galactosyl-human serum albumin(99mTc-GSA)scintigraphy/vascular fusion imaging using SYNAPSE VINCENT and to examine the discrepancy between conventional and functional volumetry.Methods:The study group comprised 15 patients who underwent preoperative 3-dimensional(3D)-99mTc-GSA scintigraphy/vascular fusion imaging using SYNAPSE VINCENT software before hepatectomy between July 2014 and August 2015.The diagnosis was hepatocellular carcinoma(n=4),metastatic liver tumor(n=10),or intrahepatic cholangiocarcinoma(n=1).Right hepatectomy was performed in 2 patients,left hepatectomy in 3 patients,right posterior sectionectomy in 3 patients,segmentectomy in 2 patients,and partial hepatectomy in 4 patients.99mTc-GSA scintigraphy and computed tomography(CT)were performed to construct 3D-99mTc-GSA scintigraphy/vascular fused images.The conventional volume ratio of the planned resection region without tumor(%CT),and the functional volume ratio of the planned resection region without tumor(%GSA)were calculated.The discrepancy ratio was calculated as follows:discrepancy ratio=100-%GSA/%CT×100(%).Results:The%GSA(17.9±16.7%)was significantly lower than the%CT(21.5±17.6%)(P<0.036).In all except 2 patients,the%GSA was lower than the%CT.The discrepancy ratio ranged from-4%to 75%(median,20.7%).Conclusion:3D-99mTc-GSA scintigraphy/vascular fused images constructed using SYNAPSE VINCENT were useful for noninvasively performing functional liver volumetry in patients scheduled to undergo various patterns of hepatectomy.In planned resection regions without tumor,the functional volume ratio was about 20%lower than the conventional volume ratio.
