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.

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.

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.

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 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.

[A case of effective bisphosphonate therapy for bone metastasis from breast cancer with multiorganic metastases].

A 50-year-old woman with a past history of breast cancer was referred to our department of radiology for detailed examination after abnormal shadows on chest x-ray were detected following a routine medical examination. After lung biopsy via thoracotomy, segmental resection of the lung was performed and mediastinal lymph nodes were dissected. A histopathological diagnosis of breast cancer with lung metastasis and mediastinal lymph-node metastases was made. Later, the patient complained of pain in the left lower extremity. A diagnosis of a left tibial metastasis was made according to bone scintigraphy and MRI. Radiation therapy at 50 Gy was then initiated. Chemotherapy and hormone therapy combined with bisphosphonate therapy (Bisphonal, once in 2 weeks), was also begun. During the treatment, the patient had multiple organ metastases including multiple brain metastases, and metastases to submental lymph nodes and the left adrenal gland. However, her bone metastasis was limited to the left tibial bone and no other bone lesions were detected by bone scintigraphy and MRI. She did not experience adverse effects from the bisphosphonate therapy. We consider that the inhibition of extension and further metastases of the tibial bone metastasis noted in this patient reflected the efficacy of bisphosphonate therapy, and that bisphosphonate therapy might become an essential treatment in patients with bone metastasis of breast cancer.

Serendipitous detection of Cushing's disease by FDG positron emission tomography and a review of the literature.

A 70-year-old woman was referred for F-18 fluorodeoxyglucose (FDG) positron emission tomographic (PET) imaging of the brain to evaluate progressive dementia and neuropsychiatric symptoms. Although she had a history of hypertension and diabetes mellitus, she did not exhibit phenotypic features of Cushing's disease. The FDG-PET images revealed marked FDG uptake in the pituitary gland but no evidence of degenerative dementia. Two macroadenomas were confirmed by magnetic resonance imaging. Endocrinologic evaluation revealed Cushing's disease. After surgical resection of the tumors, the patient's symptoms decreased markedly.

Cerebral lesions incidentally detected on 2-deoxy-2-[18F]fluoro-D-glucose positron emission tomography images of patients evaluated for body malignancies.

OBJECTIVES: The purpose of this work was done to evaluate the value of including the brain in the field of view of a whole-body 2-deoxy-2-[18F] fluoro-D-glucose positron emission tomography (FDG-PET) study of patients referred for the evaluation of body malignancies. METHODS: A total of 1026 consecutive patients were included in this work. The primary diagnoses were the following: lung (n = 253), colorectal (n = 148), head and neck (n = 61), lymphoma (n = 249), melanoma (n = 84), and others (n = 231). Whole-body FDG images including the brain were acquired with a dedicated PET tomograph (GE advance, General Electronic Medical Systems, Milwaukee, WI) one hour after the intravenous administration of 10 mCi of FDG. Two experienced nuclear medicine physicians interpreted the images. Positive findings in the brain or the skull were correlated with other imaging studies and clinical follow-up. RESULTS: Abnormal findings were detected in 3.9% (40/1026) of the patients. Among the 40 abnormal focal lesions, 29 patients had a known history of cerebral disease, cerebrovascular or metastatic disease in most patients. Of the 11 patients without a prior history of cerebral disease, four patients had increased focal FDG uptake suggestive of metastases. Among these, two were proven clinically, one was proven to be a skull base metastasis on MRI, and the other had negative clinical follow-up, but only of two months duration. The other seven patients had a decreased focal FDG uptake most consistent with infarct, one was proven clinically, and the other six had a negative clinical follow-up (mean of 6.3 months, range 1-10), but had multiple risk factors for cerebrovascular disease. CONCLUSIONS: We conclude that FDG-PET screening for cerebral lesions in patients with body malignancy has little clinical impact. Unsuspected cerebral or skull metastases were detected in 0.4% (4/1026) of the patients.