Exploration of the threshold SUV for diagnosis of malignancy using 18F-FBPA PET/CT.

BACKGROUND: The goal of the study was to evaluate the diagnostic ability of 18F-FBPA PET/CT for malignant tumors. Findings from 18F-FBPA and 18F-FDG PET/CT were compared with pathological diagnoses in patients with malignant tumors or benign lesions. METHODS: A total of 82 patients (45 males, 37 females; median age, 63 years; age range, 20-89 years) with various types of malignant tumors or benign lesions, such as inflammation and granulomas, were examined by 18F-FDG and 18F-FBPA PET/CT. Tumor uptake of FDG or FBPA was quantified using the maximum standardized uptake value (SUVmax). The final diagnosis was confirmed by cytopathology or histopathological findings of the specimen after biopsy or surgery. A ROC curve was constructed from the SUVmax values of each PET image, and the area under the curve (AUC) and cutoff values were calculated. RESULTS: The SUVmax for 18F-FDG PET/CT did not differ significantly for malignant tumors and benign lesions (10.9 ± 6.3 vs. 9.1 ± 2.7 P = 0.62), whereas SUVmax for 18F-FBPA PET/CT was significantly higher for malignant tumors (5.1 ± 3.0 vs. 2.9 ± 0.6, P < 0.001). The best SUVmax cutoffs for distinguishing malignant tumors from benign lesions were 11.16 for 18F-FDG PET/CT (sensitivity 0.909, specificity 0.390) and 3.24 for 18F-FBPA PET/CT (sensitivity 0.818, specificity 0.753). ROC analysis showed significantly different AUC values for 18F-FDG and 18F-FBPA PET/CT (0.547 vs. 0.834, p < 0.001). CONCLUSION: 18F-FBPA PET/CT showed superior diagnostic ability over 18F-FDG PET/CT in differential diagnosis of malignant tumors and benign lesions. The results of this study suggest that 18F-FBPA PET/CT diagnosis may reduce false-positive 18F-FDG PET/CT diagnoses.

Prevalence and Risk Factors of Silent Cerebral Microbleeds in Patients with Coronary Artery Disease.

OBJECTIVES: Cerebral microbleeds (CMBs), which can be detected by gradient-echo T2*-weighted magnetic resonance imaging (MRI), represent small chronic brain hemorrhages caused by structural abnormalities in cerebral small vessels. CMBs are known to be a potential predictor of future stroke, and are associated with age, various cardiovascular risk factors, cognitive impairment, and the use of antithrombotic drugs. Patients with coronary artery disease (CAD) are at potentially high risk of CMBs due to the presence of coexistent conditions. However, little is known about CMBs in patients with CAD. We aimed to identify the factors associated with the presence of CMBs among patients with CAD. METHODS: We evaluated 356 consecutive patients [mean age, 72 ± 10 years; men = 276 (78%)] with angiographically proven CAD who underwent T2*-weighted brain MRI. The brain MRI was assessed by researchers blinded to the patients' clinical details. RESULTS: CMBs were found in 128 (36%) patients. Among 356 patients, 119 (33%) had previously undergone percutaneous coronary intervention (PCI), and 26 (7%) coronary artery bypass grafting (CABG). There was no significant relationship between CMBs and sex, hypertension, dyslipidemia, diabetes mellitus, anticoagulation therapy, antiplatelet therapy, or prior PCI. CMBs were significantly associated with advanced age, previous CABG, eGFR, non-HDL cholesterol, carotid artery disease, long-term antiplatelet therapy, and long-term dual antiplatelet therapy (DAPT) using univariate logistic regression analysis. The multivariate logistic regression analysis showed that long-term antiplatelet therapy (odds ratio, 1.73; 95% CI, 1.06 - 2.84; P = 0.03) or long-term DAPT (odds ratio, 2.92; 95% CI, 1.39 - 6.17; P = 0.004) was significantly associated with CMBs after adjustment for confounding variables. CONCLUSIONS: CMBs were frequently observed in patients with CAD and were significantly associated with long-term antiplatelet therapy, especially long-term DAPT.

Correction to: Increased prevalence of cerebral microbleeds in patients with low left ventricular systolic function.

In the original publication of the article, under the results section, the following sentence.

Increased prevalence of cerebral microbleeds in patients with low left ventricular systolic function.

Gradient-echo T2-star (T2*)-weighted magnetic resonance imaging (MRI) is a sensitive method to detect cerebral microbleeds (CMBs). The presence of CMBs was reported to be a marker of future cardiovascular mortality and is associated with various cardiovascular risk factors, use of antithrombotic drugs, and cognitive dysfunction. However, the relationship between cardiac function and CMBs remains unclear. We investigated the association between cardiac function and presence of CMBs in patients with cardiovascular diseases. This single-center retrospective study included a total of 424 participants (mean age 70 ± 12 years; men 286 (67%); mean left ventricular ejection fraction (LVEF) 61% ± 12%] who underwent echocardiography and brain T2*-weighted MRI within 1 month without neurologic abnormality. CMBs were found in 118 (28%) patients. There was no significant relationship between CMBs and anticoagulant or antiplatelet therapy. LVEF was significantly lower in patients with CMBs than in those without CMBs (59% ± 13% vs. 62% ± 11%, P < 0.05). On multivariate logistic analysis, lower LVEF [odds ratio (OR) 0.98, 95% confidence interval (CI) 0.96-1.00; P < 0.05] and age (OR 1.02, 95% CI 1.00-1.05; P < 0.05) were significantly associated with CMBs. The presence of CMBs was frequently observed in the patients with cardiovascular disease and was significantly associated with age and LVEF.

Improved diagnosis of the number of stenosed coronary artery vessels by segmentation with scatter and photo-peak window data for attenuation correction in myocardial perfusion SPECT.

BACKGROUND: Attenuation correction using segmentation of scatter and photo-peak window data (SSPAC) enables an evaluation of the attenuation map in a patient-specific manner without additional radiation exposure. We compared the accuracy of SSPAC and non-corrected myocardial perfusion scintigraphy methods for diagnosing the number of stenosed coronary artery vessels. METHODS AND RESULTS: We retrospectively reviewed the data from 183 consecutive patients who underwent 99mTc-tetrofosmin stress/rest SPECT examination and a coronary angiography within 3 months. The MPS images were reconstructed with and without SSPAC attenuation correction. We examined the accuracy of the quantitative interpretation using summed differential score in the detection of coronary artery disease (CAD). The attenuation maps were successfully determined in 179 of 183 patients (98%). In terms of the vessel-based diagnostic ability, sensitivity, specificity, positive predictive and negative predictive values of the SSPAC and non-correction methods for diagnosing CAD in individual coronary territories were 77%*, 89%, 74%*, and 90%* vs 51%, 87%, 62%, and 82%, respectively (*P < .05). In 35 patients with multi-vessel CAD, those values were 78%*, 81%, 93%, and 55%* vs 49%, 81%, 89%, and 34%, respectively (*P < .05; AUC: 0.82 vs 0.62, P < .05). CONCLUSION: SSPAC-corrected SPECT myocardial perfusion images exhibit improved accuracy in the detection of the number of stenosed coronary artery vessels, even in patients with multi-vessel CAD.

Detectability of residual invasive bladder cancer in delayed 18F-FDG PET imaging with oral hydration using 500 mL of water and voiding-refilling.

OBJECTIVE: 2-Fluorine-18-fluoro-2-deoxy-D-glucose positron emission tomography (18F-FDG PET) imaging is not considered useful for assessing bladder cancer due to the physiological uptake of 18F-FDG in the bladder. Despite reports of the detection of bladder cancer by washing out 18F-FDG from the bladder, such methods are invasive and impractical in the routine practice. The purpose of this study was to evaluate prospectively the utility of oral hydration with 500 mL of water and voiding-refilling, a minimally invasive method that we introduced to enable detection of residual invasive bladder cancer on delayed 18F-FDG PET imaging. METHODS: From January 2015 to December 2017, 267 consecutive patients with bladder cancer underwent 18F-FDG PET/computed tomography scans. Among these patients, 25 (19 men and 6 women; mean age, 72.0 ± 11.3 years) were newly diagnosed as having muscle-invasive bladder cancer by transurethral resection of bladder tumor and T3b or T4 by magnetic resonance imaging (MRI). All patients were orally hydrated with only 500 mL of water and were then instructed to void frequently for 60 min before early 18F-FDG PET imaging. After the scans, they were instructed to hold their urine for 60 min. Then, delayed imaging was performed. Two radiologists evaluated the early and delayed 18F-FDG PET images to determine whether residual invasive bladder cancer could be detected. The maximum standardized uptake values (SUVmax) of the bladder urine and residual tumor site were also measured on early and delayed images. The maximum diameter of the primary bladder tumor was measured on MRI. RESULTS: The sensitivity for detecting residual invasive bladder cancer on early and delayed imaging were 24.0 and 92.0%, respectively (P < 0.001). The SUVmax of the bladder urine on the early and delayed imaging were 34.7 ± 29.7 and 16.0 ± 10.7 (mean ± SD), respectively. The SUVmax of the residual tumor site on the early and delayed imaging were range 15.65-30.83 and 10.06-45.70, respectively. CONCLUSION: Delayed 18F-FDG PET imaging with oral hydration using only 500 mL of water and voiding-refilling is useful for detecting residual invasive bladder cancer.

Central Nervous System Involvement of Intravascular Large B-Cell Lymphoma on 18F-FDG PET/CT.

Intravascular large B-cell lymphoma is a rare subtype of extranodal diffuse large B-cell lymphoma. We present a case of intravascular large B-cell lymphoma with central nervous system involvement that can be detected on F-FDG PET and may be useful for applications in biopsy and diagnosis.

Differentiation between Polymyalgia Rheumatica (PMR) and Elderly-Onset Rheumatoid Arthritis Using 18F-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography: Is Enthesitis a New Pathological Lesion in PMR?

BACKGROUND: It is difficult to differentiate polymyalgia rheumatica (PMR) from elderly-onset rheumatoid arthritis (EORA) in clinical practice. We compared FDG-PET/CT findings between patients with PMR and those with EORA and extracted factors useful for differentiating the two disorders. METHODS: We compared abnormal FDG accumulation sites and maximum standardized uptake value (SUVmax) between 15 patients with PMR and 7 with EORA in whom FDG-PET/CT was performed. RESULTS: The proportion of patients in the PMR group with abnormal FDG accumulation at the following 9 sites on FDG-PET/CT was significantly higher than that in the EORA group: periarticular region of the scapulohumeral joint, enthesis of the pectineus muscle, vicinity of the enthesis of the rectus femoris muscle, lateral side of the greater trochanter, ischial tuberosity, hip joint, spinous process of the lower cervical vertebra, intervertebral joint of the lumbar vertebra, and spinous process of the lumbar vertebra. The PET/CT score was evaluated at 9 sites consisting of the abovementioned sites. The median score in the PMR group was 8, which was significantly higher than that of 0 in the EORA group (P = 0.0003). ROC curve analysis was performed with the PET/CT scores, and a score of 5 was shown to maximize the area under the ROC curve (sensitivity: 86.7%, specificity: 86.7%). CONCLUSIONS: FDG-PET/CT is useful for differentiating PMR from EORA. In patients with PMR, abnormal FDG accumulation was observed at the entheses, suggesting the presence of enthesitis in addition to bursitis and synovitis.

The Association between Cerebral White Matter Lesions and Plasma Omega-3 to Omega-6 Polyunsaturated Fatty Acids Ratio to Cognitive Impairment Development.

OBJECTIVE: Cerebral white matter hyperintensity (WMH) with magnetic resonance imaging (MRI) has a potential for predicting cognitive impairment. Serum polyunsaturated fatty acid (PUFA) levels are important for evaluating the extent of atherosclerosis. We investigated whether abnormal PUFA levels affected WMH grading and cognitive function in patients without significant cognitive impairment. METHODS: Atherosclerotic risk factors, the internal carotid artery (ICA) plaque, and serum ratios of eicosapentaenoic to arachidonic acids (EPA/AA) and docosahexaenoic to arachidonic acids (DHA/AA) were assessed in 286 patients. The relationship among these risk factors, WMH, and cognitive function was evaluated using WMH grading and the Mini-Mental State Examination (MMSE). RESULTS: The development of WMH was associated with aging, hypertension, ICA plaques, and a low serum EPA/AA ratio (<0.38, obtained as the median value) but was not related to dyslipidemia, diabetes, smoking, and a low serum DHA/AA ratio (<0.84, obtained as the median value). In addition, the MMSE score deteriorated slightly with the progression of WMH (29.7 ± 1.0 compared to 28.4 ± 2.1, P < 0.0001). CONCLUSIONS: The progression of WMH was associated with a low serum EPA/AA ratio and accompanied minimal deterioration in cognitive function. Sufficient omega-3 PUFA intake may be effective in preventing the development of cognitive impairment.

Presence of Postsystolic Shortening Increases the Likelihood of Coronary Artery Disease: A Rest Electrocardiography-Gated Myocardial Perfusion SPECT Study.

UNLABELLED: Postsystolic shortening (PSS), which is a delayed myocardial contraction that occurs after end-systole, has been considered an important diagnostic index of myocardial ischemia. Recent technological advancements in quantitative gated SPECT (QGS) software enables the left ventricular (LV) regional analysis and may be useful for PSS measurement. The purpose of this study was to evaluate whether PSS at the resting condition determined by QGS is useful to identify patients with coronary artery disease. METHODS: The study comprised 146 patients (mean age ± SD, 71 ± 8 y; 98 men) with normal LV wall motion (mean LV ejection fraction ± SD, 72% ± 9%) who underwent both coronary angiography and resting (99m)Tc-tetrofosmin myocardial perfusion SPECT. The sum of the difference between post-end-systolic maximal LV thickening and end-systolic LV thickening, designated PSS index, was calculated from 17 LV myocardial segments using QGS. RESULTS: The PSS index was significantly higher in patients with significant stenosis of the coronary artery than in the other patients (9.8 ± 10.2 vs. 5.6 ± 5.1; P < 0.01). A cutoff point of 6.0 of the PSS index had sensitivity, specificity, positive predictive value, and negative predictive values of 55%, 70%, 76%, and 47%, respectively, for the diagnosis of coronary artery disease. Multivariate logistic regression analysis demonstrated that a PSS index greater than 6.0 was an independent predictor for the presence of coronary artery disease (odds ratio, 2.46; 95% confidence interval, 1.1-5.4; P < 0.05). CONCLUSION: Among subjects with normal LV function, PSS index even in the resting condition determined using QGS may help to identify patients with coronary artery disease.

Novel attenuation correction of SPECT images using scatter photopeak window data for the detection of coronary artery disease.

BACKGROUND: Attenuation correction using segmentation with scatter and photopeak window data (SSPAC) may enable evaluation of the attenuation map in a patient-specific manner without the need for additional radiation exposure and more acquisition time. We examined the feasibility of SSPAC and compared the sensitivity, specificity, and accuracy of this new correction method with that of conventional non-corrected myocardial perfusion single-photon emission computed tomography (SPECT) among patients with suspected or diagnosed coronary artery disease. METHODS AND RESULTS: One hundred sixty-one patients who underwent both (99m)Tc-tetrofosmin stress/rest SPECT examination and invasive coronary angiography were enrolled in the study. Data from the SSPAC-corrected and non-corrected methods were analyzed quantitatively using summed stress scores. Attenuation maps were obtained successfully for 150 (93%) of the patients. The SSPAC-corrected and non-corrected methods accurately predicted coronary artery disease defined as >50% luminal stenosis verified by coronary artery angiography and/or prior myocardial infarction, for 91% and 77% patients, respectively (P < .05). For diagnosis of coronary artery disease, SSPAC improved sensitivity in the left anterior descending artery territory and specificity in the right coronary artery territory. CONCLUSIONS: Attenuation correction with SSPAC may be a feasible method of correction for myocardial perfusion SPECT and in some cases may provide better accuracy for diagnosing coronary artery disease.

Rapidly progressing aneurysm of infected thoracic aorta with pseudoaneurysm formation.

A 60-year-old man presented with chest discomfort with fever and high C-reactive protein (CRP). Chest computed tomography (CT) disclosed a mediastinal soft tissue swelling originating from the aortic arch, and gallium-67 single-photon emission CT revealed intense uptake in the same region. We initially suspected mediastinitis and/or a thoracic aortic infection. Antibiotics improved his symptoms and CRP levels. However, a follow-up CT scan 33 days later, revealed an aortic arch aneurysm and the patient was diagnosed with infective aortic aneurysm. Here, we report a rare case of a rapidly progressing aneurysm of infected aorta aortic infection with pseudoaneurysm formation.

2-[Fluorine-18]-fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography versus whole-body diffusion-weighted MRI for detection of malignant lesions: initial experience.

OBJECTIVES: The new magnetic resonance whole body diffusion-weighted imaging with background body signal suppression (DWIBS) uses short tau inversion recovery-echo planar imaging sequence under normal respiration. DWIBS is different from 2-[fluorine-18]-fluoro-2-deoxy-D: -glucose positron emission tomography ((18)F-FDG PET) imaging in technology, but their images are similar. We compared the two modalities regarding the detection and characterization of malignant tumors. METHODS: DWIBS and (18)F-FDG PET/computed tomography (CT) were performed on 16 cancer patients on the same day. The diagnoses were the following: lung cancer (n = 12), colon cancer (n = 2), breast cancer (n = 1), and pulmonary metastasis (n = 1). A total of 27 malignant tumors (15 lung cancer, 5 pulmonary metastases of parathyroid cancer, 3 pulmonary metastases of lung cancer, 3 colon cancer, 1 breast cancer) and seven reference organs around malignant lesions (two liver regions, four normal lymph nodes, one muscle region) were evaluated visually and quantitatively using the apparent diffusion coefficient (ADC) (x10(-3) mm(2)/s) and standardized uptake value (SUV). RESULTS: Twenty-five (92.6%) of the 27 malignant lesions were detected visually with DWIBS imaging in contrast to 22 malignant tumors (81.5%) with (18)F-FDG PET/CT imaging. The quantitative evaluation showed that there was a significant difference between the mean SUVs of the reference organs (n = 7, 1.48 +/- 0.62) and the malignant (n = 22, 5.36 +/- 2.80) lesions (P < 0.01). However, there was no significant difference between the mean ADCs of the reference organs (n = 7, 1.54 +/- 0.24) and the malignant (n = 25, 1.18 +/- 0.70) lesions. CONCLUSIONS: DWIBS can be used for the detection of malignant tumors or benign tumors; however, it may be difficult to differentiate between benign and malignant lesions by ADC.

[Evaluation of the product-specific standard input function for the IMP-ARG method].

To confirm the previous reports demonstrating the difference in the octanol extraction fractions between the currently available two N-isopropyl-4-iodoamphetamine (123I) products (IMP(A) and IMP(B)), we newly developed the standard input function for IMP(B) in 19 healthy volunteers and compared it with the established standard input function, which has been originally generated with IMP(A). The octanol extraction fractions of IMP(B) were stable from 5 minutes to 16 minutes post injection and significantly higher than those of IMP(A). The mCBFs calculated with IMP(B) by using the established standard input function for IMP(A) tended to be higher than those with the combination of IMP(A) and the established standard input function though the difference was not significant. When measured with IMP(B) combined with the correspondent standard input function, mCBFs were identical to those calculated with IMP(A) with the established standard input function, suggesting that the appropriate standard input function should be used according to the product used.

Comparison of methods of attenuation and scatter correction in brain perfusion SPECT.

OBJECTIVE: The radioactivity count distribution in the brain must be determined accurately to accurately measure cerebral blood flow (CBF). Scatter and attenuation are factors that compromise the accuracy of determining radioactivity counts in the brain. METHODS: We compared regional CBF in patients by an autoradiographic method using N-isopropyl-p-[123I] iodoamphetamine when, first, attenuation correction alone was performed uniformly on SPECT images by using empiric mu-values (Chang method); second, scatter correction was performed and the mu-values of a homogeneous-attenuation body of water were used for attenuation correction (triple-energy window [TEW]+Chang method); and third, scatter correction was performed and the mu-values calculated by CT were used for attenuation correction (TEW+CT method). We also compared regional CBF measured by these methods with the values obtained by the xenon CT/CBF method, which uses CT and stable xenon. RESULTS: Scatter correction reduced overestimation of regional CBF in low-flow regions. The TEW+CT method yielded better regional and overall correlations with the xenon CT/CBF method than did either of the other methods. CONCLUSION: The TEW+CT method of correction gave the most accurate measurements of regional CBF.

Evaluation of breath-hold 201Tl SPECT in the differential diagnosis of solitary pulmonary nodules.

UNLABELLED: The aim of this study was to evaluate the usefulness of deep inspiration breath-hold SPECT (BrST, a method for 201Tl SPECT) in the diagnosis of solitary pulmonary nodules (SPN). METHODS: Ten patients with malignant lesions and five with benign lesions were enrolled in this study. Early SPECT acquisition was performed 15 min after injection of 201Tl, while delayed SPECT images were acquired 3 h after injection. The first 15-sec acquisition was done using the BrST technique, and the second with the conventional free breathing (FB) method. We performed this technique alternately, and therefore, the odd data were from BrST and the even data were from FB. We referred to the T/N ratio of the early images as the ER and to the T/N ratio of the delayed images as the DR. To semi-quantitatively evaluate the degree of retention in the lesion, the retention index (RI) was calculated. RESULTS: The RI of BrST indicated greater accuracy than that of FB in the differential diagnosis of SPN. For the benign and malignant lesions, the RI of BrST was -3.07 +/- 31.51 and 29.86 +/- 25.01, respectively (p < 0.05). The sensitivity, specificity, and accuracy of BrST (80%, 80%, and 80%, respectively) were significantly higher than those of FB (p < 0.05). CONCLUSION: The BrST method is more accurate than that of the conventional FB method in the differential diagnosis of SPN.

Comparative study of quantitative blood pool SPECT imaging with 180 degrees and 360 degrees acquisition orbits on accuracy of cardiac function.

BACKGROUND: Quantitative blood pool single photon emission computed tomography (SPECT) (QBS) can measure ejection fraction (EF) and volumes from gated blood pool single photon emission tomography (GBPS) working in fully automatic mode in 3-dimensional space. The effects of 180 degrees and 360 degrees data acquisition in GBPS have not been fully evaluated. This study compares the accuracy of 360 degrees and 180 degrees data acquisition for left ventricular (LV) systolic function in a clinical study and measures LV volume by GBPS compared with ultrasound echocardiography. METHODS AND RESULTS: The study population comprised 9 normal volunteers and 34 patients. GBPS data were acquired by use of 360 degrees rotation and 60 stops per head. All 60 (360 degrees ) and 30 (45 degrees right anterior oblique to 45 degrees left posterior oblique) pieces of projection data that were selected for reconstructing the 180 degrees data were reconstructed and both ventricular functional parameters were automatically obtained by QBS software. The contour of the LV septal wall was concave in 6 patients (14%) when processed at 180 degrees , whereas a concave septum at 360 degrees processing was observed in only 1 patient (2%). The coefficients of correlation between 180 degrees and 360 degrees were 0.467 for the end-diastolic volume (EDV) and 0.648 for the end-systolic volume (ESV). The mean 180 degrees EDV value (152.9 +/- 46.1 mL) was significantly smaller than that of the 360 degrees EDV (191 +/- 70.8 mL) ( P < .001). However, there was no significant difference between the 360 degrees EDV (0.623) and 180 degrees EDV (0.407) as compared by echocardiography ( P = .218). The agreement of the EF between both methods was close ( r = 0.894, P < .0001). The agreement of the right ventricular volumes between the 180 degrees and 360 degrees orbits was close ( r = 0.800 for EDV and 0.706 for ESV). The EF was relatively dispersed between the 180 degrees and 360 degrees methods ( r = 0.642). CONCLUSION: This study showed that SPECT image acquisition by use of both the 180 degrees method and the 360 degrees method considerably underestimated LV volume quantification. In addition, the LV volume with the 180 degrees method was significantly smaller than that with the 360 degrees method. Thus a 360 degrees acquisition orbit may be suitable for more quantitatively accurate results when blood pool imaging is performed with gated SPECT.