Images in cardiovascular medicine. Continuous thrombus in the right and left atria penetrating the patent foramen ovalis.
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Adult↗
Biomedical subjects
Tsunehiko Nishimura
Publications and source records attributed to Tsunehiko Nishimura.
Pitfalls of FDG-PET for the diagnosis of osteoblastic bone metastases in patients with breast cancer.
PURPOSE: The purpose of this study was to investigate the pitfalls of using 2-[18F]-fluoro-2-deoxy-D: -glucose positron emission tomography (FDG-PET) for the evaluation of osteoblastic bone metastases in patients with breast cancer by comparing it with (99m)Tc-hydroxymethylene diphosphonate bone scintigraphy. METHODS: Among the 89 breast cancer patients (mean age 59+/-15 years) who had undergone both FDG-PET and bone scintigraphy within 1 month between September 2003 and December 2004, 55 with bone metastases were studied. The bone metastases were visually classified by multi-slice CT into four types according to their degree of osteosclerosis and osteolysis-osteoblastic, osteolytic, mixed and invisible-and compared in terms of tracer uptake on FDG-PET or bone scintigraphy and SUV(mean) on FDG-PET. Differences in the rate of detection on bone scintigraphy and FDG-PET were analysed for significance by the McNemar test. RESULTS: The sensitivity, specificity and accuracy of bone scintigraphy were 78.2%, 82.4% and 79.8% respectively, and those of FDG-PET were 80.0%, 88.2% and 83.1%, respectively, revealing no significant differences. According to the CT image type, the visualisation rate of bone scintigraphy/FDG-PET was 100%/55.6% for the blastic type, 70.0%/100.0% for the lytic type, 84.2%/94.7% for the mixed type and 25.0%/87.5% for the invisible type. The visualisation rates of bone scintigraphy for the blastic type and FDG-PET for the invisible type were significantly higher. The SUV(mean) of the blastic, lytic, mixed and invisible types were 1.72+/-0.28, 4.14+/-2.20, 2.97+/-1.98 and 2.25+/-0.80, respectively, showing that the SUV(mean) tended to be higher for the lytic type than for the blastic type. CONCLUSION: FDG-PET showed a low visualisation rate in respect of osteoblastic bone metastases. Although FDG-PET is useful for detection of bone metastases from breast cancer, it is apparent that it suffers from some limitations in depicting metastases of the osteoblastic type.
Bone Neoplasms↗
Higher lesion conspicuity for SENSE dynamic MRI in detecting hypervascular hepatocellular carcinoma: analysis through the measurements of liver SNR and lesion-liver CNR comparison with conventional dynamic MRI.
The aim of our study was to compare the signal-to-noise ratio (SNR) of liver parenchyma and the contrast-to-noise ratio (CNR) of hypervascular hepatocellular carcinoma (HCC) between conventional and SENSE dynamic MRI. Thirty-one consecutive patients who were strongly suspected of having HCC were enrolled in our study. The subjects consisted of 20 men and 11 women aged 52 years to 79 years (mean 66.8 years). Dynamic MRI was performed for each patient, with SENSE (SENSE MRI) and without SENSE (conventional MRI) on separate days. For the quantitative analysis, the liver SNR and the lesion-liver CNR of 25 hypervascular HCCs detected on both conventional and SENSE dynamic MRI were measured. The liver SNR of the arterial phase and the portal venous phase was 84.1+/-24.7 and 104.7+/-34.3, respectively, in conventional MRI, while it was 62.9+/-19.5 and 44.5+/-18.2, respectively, in SENSE MRI. SENSE MRI showed a statistically significantly lower SNR than conventional MRI (P<0.01). The lesion-liver CNR was 26.3+/-15.9 in conventional MRI and 39.0+/-19.6 in SENSE MRI. The lesion-liver CNR in SENSE MRI was significantly higher than in conventional MRI (P<0.01). The SNR in SENSE MRI is significantly lower than in conventional MRI, although the lesion CNR is significantly higher than in conventional MRI.
Aged↗
Fusion image of positron emission tomography and computed tomography for the diagnosis of local recurrence of rectal cancer.
BACKGROUND: The aim of this study was to evaluate the clinical and therapeutic value of digital fusion image (FI) of positron emission tomography (PET) using (18)F-fluorodeoxy glucose and computed tomography (CT) in patients who were suspected of having a local recurrence of rectal cancer. METHODS: Forty-two patients (32 men and 10 women; mean age, 61.4 years, range, 40-79 years) with a suspicion of local recurrence after curative resection of rectal cancer were prospectively recruited and underwent (18)F-fluorodeoxy glucose-PET and CT. The FI was reconstructed with a commercially available digital software program, T-B Fusion. Wilcoxon signed rank test was used to compare FI with CT alone or PET alone. RESULTS: FI yielded a correct diagnosis in 39 (93%) of 42 patients, whereas CT alone and PET alone did so in 33 (79%) and 37 (88%) patients, respectively. FI had better diagnostic accuracy than CT alone (P = .0138) and PET alone (P = .0156). Overall, FI altered patient management in 11 (26.2%) patients on the basis of additional information, including differentiation of the tumor from the postoperative scar in 6 patients, exact anatomical location in 3 patients, and both in 2 patients. CONCLUSIONS: FI has a potential clinical value in the treatment of suspected local recurrence of rectal cancer.
Adenocarcinoma↗
Fiber-tracking does not accurately estimate size of fiber bundle in pathological condition: initial neurosurgical experience using neuronavigation and subcortical white matter stimulation.
The fiber-tracking method enables in vivo visualization of the white matter tracts of the brain using a diffusion tensor MR imaging technique. While this method represents a promising tool in the field of neurosurgery, especially when confronted with brain tumors in eloquent areas, its reliability remains unknown. We present here our preliminary validation of tractography in human subjects harboring brain tumors by comparing the results produced by neuronavigation and electrical white matter stimulation in two patients with gliomas in the eloquent area. Although we were able to visualize the pyramidal tract with the fiber-tracking technique, the images failed to present the actual size of the fiber bundles. Here we discuss the advantages and limitations of fiber-tracking in the field of neurosurgery.
Aged↗
Relationship between contrast enhancement on fluid-attenuated inversion recovery MR sequences and signal intensity on T2-weighted MR images: visual evaluation of brain tumors.
PURPOSE: To investigate the relationship between the degree of contrast enhancement in fluid-attenuated inversion recovery (FLAIR) sequences and tumor signal intensity on T2-weighted images. MATERIALS AND METHODS: A total of 96 patients suspected of having brain tumors were examined by MR imaging, and whenever a brain tumor with an enhancing part larger than the slice thickness was demonstrated on postcontrast T1-weighted images, postcontrast FLAIR images were additionally acquired. The tumor signal intensity on the T2-weighted images was visually classified as follows: equal or lower compared with normal cerebral cortex (group 1), higher than normal cortex (group 2), and as high as cerebrospinal fluid (CSF) (group 3). When a lesion contained several parts with different signal intensities on T2-weighted images, we assessed each part separately. In each group, we visually compared pre- and postcontrast FLAIR images and assessed whether tumor contrast enhancement was present. When contrast enhancement was present on FLAIR sequence, the degree of contrast enhancement in T1-weighted and FLAIR sequences was visually compared. RESULTS: Postcontrast T1-weighted images showed 46 enhancing lesions, including 48 parts, in 31 MR examinations. FLAIR images of the lesion-parts in group 1 (N=18) did not show significant contrast enhancement. In group 2 (N=12), all the parts were enhanced in FLAIR sequences, and three parts were enhanced more clearly in the FLAIR sequences than in the T1-weighted sequences. In group 3 (N=18), all the parts were enhanced equally or more clearly in the FLAIR sequences than in the T1-weighted sequences. CONCLUSION: The signal intensity in FLAIR sequences is largely influenced by both T1 and T2 relaxation time; there is a close relationship between the signal intensity of brain tumors on T2-weighted images and the degree of contrast enhancement on FLAIR sequences. When tumors have higher signal intensity than normal cortex on T2-weighted images, additional postcontrast FLAIR imaging may improve their depiction.
Adenoma↗
Imaging of lesions in a murine rheumatoid arthritis model with a humanized anti-interleukin-6 receptor antibody.
Rheumatoid arthritis (RA) has been attributed to the abnormal production of cytokine interleukin-6 (IL-6), which has a variety of physiological activities. In vivo IL-6-receptor imaging provides useful suggestions regarding the mechanism of anti-IL-6-receptor antibody action and indicates a basic therapeutic strategy for treating RA. Therefore, this study was designed to establish a method for radiolabeling anti-IL-6-receptor antibodies and to investigate the feasibility of using radiolabeled anti-IL-6-receptor antibodies in the scintigraphic imaging of lesions in an animal RA model. Anti-IL-6-receptor antibodies were conjugated with a bifunctional chelating agent, hydrazinonicotinamide (HYNIC), and radiolabeled with technetium-99m (99mTc) using the ligand exchange reaction of 99mTc-tricine complex. The binding affinity was estimated using the U266 cell line. Whole body scintigraphy, biodistribution and autoradiography were undertaken in mice containing synovial cells that had been transplanted from an RA patient. Our findings showed that the antibodies accumulated in the implanted tissue. When radiolabeled anti-IL-6-receptor antibodies are used in scintigraphic imaging, the distribution of the IL-6-receptors is associated with the inflammatory cell infiltration that is seen in the early stage of RA. Accordingly, imaging with humanized anti-IL-6-receptor antibodies appears to be useful for detecting early pathophysiological conditions and assessing the efficacy of antibody treatment as well as the prognosis of patients with RA.
Animals↗
Evaluation of the hemodynamics of the femoral head compared with the ilium, femoral neck and femoral intertrochanteric region in healthy adults: measurement with positron emission tomography (PET).
OBJECTIVE: Non-traumatic osteonecrosis of the femoral head (ONF) is considered to be a disease that occurs primarily due to ischemia of the femoral head, while its etiology and pathology are not fully understood. It is therefore necessary to identify the characteristics of the hemodynamics of the femoral head. In this study, the hemodynamics in the ilium and proximal regions of the femur, including the femoral head, was investigated using positron emission tomography (PET). METHODS: The subjects of this study consisted of 8 hip joints of four healthy male adults and 3 hip joints on the contralateral side of a femoral neck fracture, avulsion fracture of the greater trochanter and coxarthrosis (1 case each, all females) for a total of 11 hip joints of 7 subjects. The ages of the subjects ranged from 25 to 87 years (average age: 54 years). Blood flow was measured by means of the H215O dynamic study method and blood volume was measured by means of the 15O-labeled carbon monoxide bolus inhalation method. RESULTS: Blood flow was determined to be 9.1 +/- 4.8 ml/min/100 g in the ilium and among proximal regions of the femur (femoral head, neck and intertrochanteric region), 1.8 +/- 0.7 ml/min/100 g in the femoral head, 2.1 +/- 0.6 ml/min/100 g in the femoral neck, and 2.6 +/- 0.7 ml/min/100 g in the intertrochanteric region. In addition, blood volume was 4.7 +/- 1.3 ml/100 g in the ilium, and among proximal regions of the femur, 1.1 +/- 0.5 ml/100 g in the femoral head, 2.1 +/- 0.7 ml/100 g in the femoral neck, and 2.6 +/- 0.9 ml/100 g in the intertrochanteric region. The results showed that both blood flow and volume were lowest in the femoral head. Blood flow and volume were significantly lower in the proximal regions of the femur (femoral head, neck and intertrochanteric region) than in the ilium (p < 0.01). CONCLUSION: The present study demonstrated that the femoral head is in a hypoemic state as compared with other osseous tissue, indicating that even the slightest exacerbation of hemodynamics in the femoral head can trigger an ischemic condition culminating in ONF.
Adult↗
Do short-time SPECT images of bone scintigraphy improve the diagnostic value in the evaluation of solitary lesions in the thoracic spine in patients with extraskeletal malignancies?
OBJECTIVE: Single photon emission computed tomography (SPECT) images provide many details of the anatomical structure. Also about bone scintigraphy, there are many reports of the improvement of diagnosis by SPECT images. Although SPECT is useful, it requires much time. So to perform SPECT for all cases is difficult in the clinical situation. Recently, due to technical improvements in gamma cameras, we can get SPECT images in a short time. We examined diagnosis of solitary hot spots of thoracic spine in cancer patients using short-time SPECT. And we considered whether short-time SPECT contributes to the precise diagnosis of the lesion. MATERIAL AND METHODS: We performed bone scintigraphy image acquisition and both planar and short-time SPECT of the chest. Short-time SPECT was acquired in 6 minutes. We selected 36 cases with malignancy, whose bone scintigraphy demonstrated a solitary accumulation hot spot in the thoracic spine. Three experienced radiologists in nuclear medicine and 4 beginners diagnosed the images. They interpreted planar, short-time SPECT and maximum intensity projection (MIP) view of the chest of each case. The observers' response data were analyzed with receiver operating characteristic (ROC) curve analysis. RESULTS: Of the three types of images, the Az (the area under ROC curve) values of short-time SPECT were the highest in all the observers except for only one beginner. Compared with experienced observers, beginners scored lower Az values of short-time SPECT. MIP images were constructed using SPECT data, but the Az values of MIP images were not higher than those of planar images. As to diagnosis, beginners tended to interprete most of the accumulations as metastatic lesions. CONCLUSION: Short-time SPECT can be helpful to some degree, but to provide greater benefit, the observers require considerable exercise and experience.
Adult↗
Assessment of the solid-state gamma camera to depict axillary sentinel lymph nodes in breast cancer patients.
PURPOSE: The solid-state gamma camera is now commercially available offering the advantages of a compact and portable system, currently used mainly in the cardiac region. We evaluate the ability of the solid-state gamma camera to depict axillary sentinel lymph nodes (SLNs) in breast cancer patients. MATERIALS AND METHODS: Preoperative SLN lymphoscintigraphy (LSG) was performed in 19 patients with breast cancer using the solid-state gamma camera. Immediately thereafter, we performed a second LSG using a single detector Anger-type gamma camera, and compared the findings from the two cameras. RESULTS: Concordant results were obtained in 12 (63%) patients with both cameras. In 4 (21%) patients, axillary SLNs were correctly identified only with the solid-state gamma camera. In these patients, the distance between the SLN and the radiopharmaceutical injection site was closer than that of patients who had concordant results (p = 0.001). CONCLUSION: We can depict correctly axillary SLNs with the solid-state gamma camera in comparison with the Anger-type gamma camera. This technique would be useful for assessing SLNs in breast cancer patients.
Adult↗
FDG-PET in a case of multiple bone metastases of gastric cancer.
F-18 2-fluoro-2-deoxy-D-glucose (FDG) positron emission tomography (PET) is useful for surveys to detect bone metastasis because of its greater specificity than bone scintigraphy. However, FDG-PET is also known to yield false-positive results in acute fractures and inflammatory lesions, and distinguishing between benign and malignant lesions is difficult, even when semiquantitative methods are used. We report a case of multiple bone metastases of gastric cancer. One of the bone lesions that was positive for FDG uptake was benign, suggesting that FDG-PET can yield false-positive results.
Adenocarcinoma↗
Tractography to depict three layers of visual field trajectories to the calcarine gyri.
PURPOSE: Fiber-tracking by diffusion tensor magnetic resonance imaging (DT-MRI) is currently the only noninvasive in vivo method for white matter fiber-tracking in the human brain. We used this method in attempts to visualize the optic radiation and to examine the clinical applicability of this technique. DESIGN: Observational case series. METHODS: DT-MRI scans for fiber-tracking were obtained in five healthy volunteers by use of a whole-body, 1.5 Tesla imager. DT-MRI data were transferred to an off-line workstation; PRIDE software was used for image analysis. We constructed 3 diopters fiber trajectories by tracking the direction of the fastest diffusion from the lateral geniculate nucleus, and then selected tracts on the basis of anatomical knowledge of the optic radiation. RESULTS: Our method successfully reconstructed the macroscopic 3 diopters architecture of the three major groups of optic radiation in all subjects. Meyer's loop depicted by tractography was located more posterior than the known anatomical locations, although our results on the central and posterior bundles were in good agreement with them. DT-MRI scanning required 7 minutes; preliminary images of the optic radiation could be obtained in approximately 20 minutes. CONCLUSIONS: Fiber-tracking enabled us to obtain information quickly on the 3 diopters course of the optic radiation in vivo. The finding that the fiber-tracking method underestimates the anterior extent of the optic radiations could prove to be an important limitation in the utility of this technique for preoperative planning. The time required for data acquisition and processing makes this method acceptable for routine clinical use.
Adult↗
Reliability of one-point blood sampling method for calculating input function in Na18F PET.
OBJECTIVE: Conventional methods of quantitative Na18F positron emission tomography require multiple arterial blood sampling in order to obtain the input function, and the procedures are invasive and complicated. This study aims to establish a simplified and reliable technique for obtaining the input function. METHODS: Multiple arterial blood sampling was performed on 12 persons. The time point for one-point sampling was determined as the time when (1) the plasma radioactivity obtained showed the highest correlation to the real integrated value, which was calculated from the input function, and (2) the coefficient of variation of the real integrated value divided by plasma radioactivity obtained at each time point became the minimum. Scaling factors were obtained in order to estimate the plasma radioactivity at each time point, and a reference table was produced in order to estimate the input function. RESULTS: The optimal timing for one-point sampling was 12 min after intravenous injection of Na18F. The estimated integrated value obtained from arterial blood sampling at 12 min and the reference table was highly correlated with the real integrated value (P<0.001). Levels of plasma radioactivity of arterial blood and venous blood were almost the same at 12 and 40 min after Na18F injection. Percentage errors in the estimation of the integrated value were 2.63% (n=12) for the arterial blood collected at 12 min and 4.14% (n=12) for the venous blood collected at 30 min. CONCLUSIONS: This simplified method is clinically applicable and would replace traditional methods that require multiple blood sampling.
Adult↗
Efficacy of manual aspiration immediately after complicated pneumothorax in CT-guided lung biopsy.
PURPOSE: The goal of this study was to evaluate the efficacy of simple aspiration of air from the pleural space to prevent increased pneumothorax and avoid chest tube placement in cases of pneumothorax after computed tomography (CT)-guided lung biopsy. MATERIALS AND METHODS: This retrospective study was based on experience with 283 consecutive percutaneous needle lung biopsies with real-time CT fluoroscopic guidance. While patients were on the CT scanner table, percutaneous manual aspiration was performed in all those with moderate or large pneumothorax demonstrated on postbiopsy chest CT images regardless of symptoms. The authors evaluated the frequency of biopsy-induced pneumothorax, management of each such case, and factors that influenced the incidence of worsening pneumothorax that required chest tube placement despite manual aspiration. RESULTS: Of the 104 (36.7%) pneumothoraces occurring after 283 biopsy procedures, 52 were treated with manual aspiration immediately after biopsy. In 95 of the 104 pneumothoraces (91.3%), the pneumothorax had resolved completely on follow-up chest radiographs without chest tube placement. Only nine patients (3.2% of the entire series; 8.7% of those who developed pneumothorax) required chest tube placement. Requirement of chest tube insertion significantly increased parallel to the increased volume of aspirated air. The optimal cutoff level of aspirated air on which to base a decision to abandon manual aspiration alone and resort to chest tube placement was 543 mL. CONCLUSION: Percutaneous manual aspiration of biopsy-induced pneumothorax performed immediately after biopsy may prevent progressive pneumothorax and eliminate the need for chest tube placement. However, in cases in which the amount of aspirated air is large (such as more than 543 mL in this study), the possibility of required chest tube placement increases.
Adolescent↗
Percutaneous needle biopsy under CT fluoroscopic guidance for cardiac tumor during continuous intravenous injection of contrast material.
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Adult↗
Catheter redundancy in the aortic arch increases the risk of stroke in left subclavian arterial port-catheter systems.
PURPOSE: The stroke rate after left subclavian arterial port-catheter placement was compared in two groups: one with minimal redundancy of the catheter and one with pronounced redundancy in the aortic arch designed to minimize the likelihood of catheter dislocation. MATERIALS AND METHODS: One hundred forty-eight patients (102 men, 46 women; age range, 26-83 years; mean age, 64.3 years) with inoperable advanced liver cancers underwent percutaneous implantation of port-catheter systems via the left subclavian artery. In 33 patients, a pronounced redundancy of the catheter was intentionally looped in the aortic arch. Redundancy was intentionally avoided in the remaining 115 patients. The rates of brain infarction complications in these two groups were retrospectively compared. RESULTS: Among the 33 patients with pronounced redundant catheter looping, brain infarctions occurred in four cases (12.1%). In contrast, brain infarctions occurred in only three of the 115 patients with minimal redundant catheter looping (2.6%). The frequency of brain infarction complications was significantly higher in the patients with pronounced redundant catheter looping in the aortic arch than in patients with minimal pronounced redundant catheter looping (P = .044, Fisher exact test). CONCLUSION: Catheter redundancy in the aortic arch increases the risk of stroke in patients undergoing implantation of port-catheter systems via a left subclavian arterial approach for repeated hepatic arterial infusion chemotherapy.
Adult↗
Influence of extrahepatic arterial inflow into the posterior segment or caudate lobe of the liver on repeated hepatic arterial infusion chemotherapy.
PURPOSE: For therapeutic effectiveness of repeated hepatic arterial infusion chemotherapy (HAIC) for unresectable advanced liver malignancies, distribution of anticancer drugs via an indwelling catheter should be uniform throughout the entire liver. It was investigated how an extrahepatic artery entering the posterior segment or caudate lobe of the liver influences performance of repeated HAIC. MATERIALS AND METHODS: One hundred ninety-five patients with unresectable advanced liver cancer underwent placement of a percutaneously implantable port-catheter system and were followed arteriographically with and without computed tomography (CT). The frequency of poor distribution in the posterior segment or caudate lobe of the liver was observed on CT during arteriography via the port for HAIC. The correlation between poor distribution and various factors including the number of intrahepatic arteries was studied, and the management of such poor distribution is described. RESULTS: In 34 of 195 patients (17.4%), poor distribution was observed in the posterior segment and/or caudate lobe of the liver. The rate of poor distribution was significantly higher in those with two or more hepatic arteries than in those with one (13 of 35 vs 21 of 160; P = .0007, chi2 test). Other evaluated factors were not significantly correlated with such poor distribution. The right inferior phrenic artery was successfully embolized in 22 patients with tumors in segments with poor distribution. Good distribution throughout the entire liver was achieved in 21 patients (95.5%). CONCLUSION: Inflow of the right inferior phrenic artery into the liver occasionally prevents distribution of anticancer drugs throughout the entire liver during performance of long-term HAIC.
Adult↗
Radiofrequency ablation therapy of remnant colorectal liver metastases after a course of hepatic arterial infusion chemotherapy.
The present study evaluated the feasibility of combined therapy employing repeated hepatic arterial infusion chemotherapy (HAIC) via a port-catheter system and radiofrequency (RF) ablation for unresectable metastatic liver cancer from the colo-rectum. RF ablation was performed for six patients with liver malignancies that had been well controlled and had decreased in number and size with repeated HAIC. After RF ablation subsequent to repeated HAIC, all six patients had stable disease or complete or partial remission as documented by follow-up contrast-enhanced computed tomographic (CT) imaging. Fluorodeoxyglucose positron emission tomography (18F) showed complete response in all ablated lesions. In conclusion, RF ablation after a course of HAIC achieved complete necrosis in residual lesions after HAIC therapy.
Adult↗