Pulmonary alveolar microlithiasis: imaging characteristics of planar and SPECT/CT bone scan versus 18F-FDG and 18F-sodium fluoride PET/CT scanning

Pulmonary alveolar microlithiasis (PAM) is a very rare disease in which multiple microscopic calcium phosphate microliths are deposited within the alveoli of both lungs. A lung biopsy is considered to be definitive for final diagnosis; however, non-invasive imaging modalities such as chest X-ray, HRCT scan and ^99mTc-MDP bone scan suggest the diagnosis in the vast majority of patients. Although ¹⁸F-FDG PET/CT has been tried to characterize the disease, ¹⁸F-sodium fluoride PET/CT as a ‘proof-of-principle’ was tried for the first time in a known case of PAM in order to characterize the lung lesions. Interestingly, we noted that ¹⁸F-sodium fluoride PET/CT is a superior modality in characterization and assessment of the extent of disease in PAM compared to all other non-invasive imaging modalities. Thus, we recommend that ¹⁸F-sodium fluoride PET/CT should be the investigation of choice in PAM.     

The clinical effectiveness of reconstructing 18F-sodium fluoride PET/CT bone using Bayesian penalized likelihood algorithm for evaluation of metastatic bone disease in obese patients

Objective:A new Bayesian penalized likelihood reconstruction algorithm for positron emission tomography (PET) (Q.Clear) is now in clinical use for fludeoxyglucose (FDG) PET/CT. However, experience with non-FDG tracers and in special patient populations is limited. This pilot study aims to compare Q.Clear to standard PET reconstructions for ¹⁸F sodium fluoride (¹⁸F-NaF) PET in obese patients.Methods:30 whole body ¹⁸F-NaF PET/CT scans (10 patients with BMI 30–40 Kg/m² and 20 patients with BMI >40 Kg/m²) and a NEMA image quality phantom scans were analyzed using ordered subset expectation maximization (OSEM) and Q.Clear reconstructions methods with B400, 600, 800 and 1000. The images were assessed for overall image quality (IQ), noise level, background soft tissue, and lesion detectability, contrast recovery (CR), background variability (BV) and contrast-to-noise ratio (CNR) for both algorithms.Results:CNR for clinical cases was higher for Q.Clear than OSEM (p < 0.05). Mean CNR for OSEM was (21.62 ± 8.9), and for Q.Clear B400 (31.82 ± 14.6), B600 (35.54 ± 14.9), B800 (39.81 ± 16.1), and B1000 (40.9 ± 17.8). As the β value increased the CNR increased in all clinical cases. B600 was the preferred β value for reconstruction in obese patients. The phantom study showed Q.Clear reconstructions gave lower CR and lower BV than OSEM. The CNR for all spheres was significantly higher for Q.Clear (independent of β) than OSEM (p < 0.05), suggesting superiority of Q.Clear.Conclusion:This pilot clinical study shows that Q.Clear reconstruction algorithm improves overall IQ of ¹⁸F-NaF PET in obese patients. Our clinical and phantom measurement results demonstrate improved CNR and reduced BV when using Q.Clear. A β value of 600 is preferred for reconstructing ¹⁸F-NaF PET/CT with Q.Clear in obese patients.Advances in knowledge:¹⁸F-NaF PET/CT is less susceptible to artifacts induced by body habitus. Bayesian penalized likelihood reconstruction with¹⁸F-NaF PET improves overall IQ in obese patients.     

18F-sodium fluoride PET/CT provides prognostic clarity compared to calcium and Framingham risk scoring when addressing whole-heart arterial calcification

European Journal of Nuclear Medicine and Molecular Imaging - To investigate the benefit of utilizing 18F-sodium fluoride (NaF) PET/CT over calcium and Framingham scoring for potential preventative...     

Association of linear 18F-sodium fluoride accumulation in femoral arteries as a measure of diffuse calcification with cardiovascular risk factors: A PET/CT study

Background

The aim of this study was to correlate linear ¹⁸F-sodium fluoride accumulation in the femoral arteries as a measure of diffuse mineral deposition in medial elastocalcinosis with cardiovascular risk factors (RFs) and calcified plaque burden (CPB).

Methods and Results

In this study, 409 patients were examined by ¹⁸F-sodium fluoride positron emission tomography/computed tomography (PET/CT). Tracer accumulation was analyzed both qualitatively and semiquantitatively by measuring the target-to-background ratio, and compared with cardiovascular RFs and CPB. Linear ¹⁸F-sodium fluoride accumulation was observed in 159 (38.9%) patients and correlated significantly with age (P < .0001), hypertension (P < .0001), hypercholesterolemia (P = .0003), diabetes (P = .0003), history of smoking (P = .0007), prior cardiovascular events (P = .03), and CPB (P < .0001). The prevalence of linear tracer uptake increased as the number of cardiovascular RFs increased (P < .0001).

Conclusions

Linear ¹⁸F-sodium fluoride uptake in the femoral arteries (1) provides a measure of diffuse mineral deposition, (2) demonstrates a highly significant correlation with cardiovascular RFs and CPB, and (3) is found to accumulate more frequently in patients with a high-risk profile for cardiovascular events. ¹⁸F-sodium fluoride PET/CT may become a unique tool for in vivo visualization and quantification of ongoing calcification in large arteries.     

Adverse effects of increased body weight on quantitative measures of mammographic image quality

OBJECTIVE: The purpose of our study was to show that compressed breast thickness on mammograms in overweight and obese women exceeds the thickness in normal-weight women and that increased thickness results in image degradation. SUBJECTS AND METHODS: Three hundred consecutive routine mammograms were reviewed. Patients were categorized according to body mass index. Compression thickness, compressive force, kilovoltage, and milliampere-seconds were recorded. Geometric unsharpness and contrast degradation were calculated for each body mass index category. RESULTS: Body mass index categories were lean (3%), normal (36%), overweight (36%), and obese (25%). Body mass index was directly correlated with compressed thickness. In the mediolateral oblique view, the mean thickness of the obese category exceeded normal thickness by 18 mm (p < 0.01), corresponding to a 32% increase in geometric unsharpness. Mean obese thickness exceeded lean thickness by 33 mm (p < 0.01), corresponding to a 79% increase in unsharpness. Similar trends were observed for the craniocaudal view. In the mediolateral oblique projection, there was an increase of 1.0 kVp (p < 0.01) for obese compared with normal and 1.7 kVp (p < 0.01) between lean and obese, corresponding, respectively, to a 16% and a 25% decrease in image contrast because of scatter and kilovoltage changes. Milliampere-seconds increased by 47% on the mediolateral oblique images in the obese category compared with normal body mass index. CONCLUSION: An increased body mass index was associated with greater compressed breast thickness, resulting in increased geometric unsharpness, decreased image contrast, and greater potential for motion unsharpness.     

Atlas of sodium fluoride PET bone scans: atlas of NaF PET bone scans

Sodium fluoride (NaF) is a bone-seeking positron-emitting tracer with high sensitivity and specificity for detection of osseous lesions, particularly osteolytic lesions. We believe that NaF positron emission tomography (PET)/computed tomography (CT) scans can provide a more thorough and conclusive evaluation of bone diseases than conventional Technetium-99m-methylene diphosphonate bone scans. Understanding both normal and pathologic patterns is important for the evaluation and interpretation of these studies. Thus, an atlas of NaF positron emission tomography/computed tomography bone scans demonstrating benign, pathologic, and malignant osseous lesions as well as extraosseous lesions will be invaluable in the correct interpretation and diagnosis of osseous lesions.     

Comparisons between glucose analogue 2-deoxy-2-(18F)fluoro-D-glucose and 18F-sodium fluoride positron emission tomography/computed tomography in breast cancer patients with bone lesions

AIM: To compare 2-deoxy-2-(¹⁸F)fluoro-D-glucose(¹⁸F-FDG) and ¹⁸F-sodium (¹⁸F-NaF) positron emission tomography/computed tomography (PET/CT) accuracy in breast cancer patients with clinically/radiologically suspected or known bone metastases.METHODS: A total of 45 consecutive patients with breast cancer and the presence or clinical/biochemical or radiological suspicion of bone metastatic disease underwent ¹⁸F-FDG and ¹⁸F-fluoride PET/CT. Imaging results were compared with histopathology when available, or clinical and radiological follow-up of at least 1 year. For each technique we calculated: Sensitivity (Se), specificity (Sp), overall accuracy, positive and negative predictive values, error rate, and Youden’s index. McNemar’s χ² test was used to test the difference in sensitivity and specificity between the two diagnostic methods. All analyses were computed on a patient basis, and then on a lesion basis, with consideration ofthe density of independent lesions on the co-registered CT (sclerotic, lytic, mixed, no-lesions) and the divergent site of disease (skull, spine, ribs, extremities, pelvis). The impact of adding ¹⁸F-NaF PET/CT to the work-up of patients was also measured in terms of change in their management due to ¹⁸F-NaF PET/CT findings.RESULTS: The two imaging methods of ¹⁸F-FDG and ¹⁸F-fluoride PET/CT were significantly different at the patient-based analysis: Accuracy was 86.7% and 84.4%, respectively (McNemar’s χ² = 6.23, df = 1, P = 0.01). Overall, 244 bone lesions were detected in our analysis. The overall accuracy of the two methods was significantly different at lesion-based analysis (McNemar’s χ² = 93.4, df = 1, P < 0.0001). In the lesion density-based and site-based analysis, ¹⁸F-FDG PET/CT provided more accurate results in the detection of CT-negative metastasis (P < 0.002) and vertebral localizations (P < 0.002); ¹⁸F-NaF PET/CT was more accurate in detecting sclerotic (P < 0.005) and rib lesions (P < 0.04). ¹⁸F-NaF PET/CT led to a change of management in 3 of the 45 patients (6.6%) by revealing findings that were not detected at ¹⁸F-FDG PET/CT.CONCLUSION: ¹⁸F-FDG PET/CT is a reliable imaging tool in the detection of bone metastasis in most cases, with a diagnostic accuracy that is slightly, but significantly, superior to that of ¹⁸F-NaF PET/CT in the general population of breast cancer patients. However, the extremely high sensitivity of ¹⁸F-fluoride PET/CT can exploit its diagnostic potential in specific clinical settings (i.e., small CT-evident sclerotic lesions, high clinical suspicious of relapse, and negative ¹⁸F-FDG PET and conventional imaging).     

Normalization by bone volume instead of body weight or lean body mass may be better for quantifying skeletal burden in fibrous dysplasia using sodium fluoride PET/CT

European Journal of Nuclear Medicine and Molecular Imaging -     

Quantification of temporal changes in calcium score in active atherosclerotic plaque in major vessels by <Superscript>18</Superscript>F-sodium fluoride PET/CT

Purpose

Our aim was to assess whether ¹⁸F-NaF PET/CT is able to predict progression of the CT calcium score.

Methods

Between August 2007 and November 2015, 34 patients (18 women, 16 men; age, mean?±?standard deviation, 57.5?±?13.9 years; age range 19–78 years) with malignancy or orthopaedic disease were enrolled in this study, with approximately 1-year follow-up data. Baseline and follow-up CT images were retrospectively evaluated for the presence of calcification sites in major vessel walls. The maximum and mean CT values (CTmax and CTmean, in Hounsfield units), calcification volumetric score (CVS, in cubic millimetres) and Agatston units score (AU) were evaluated for each site. Subsequent changes in CTmax, CTmean, CVS and AU were calculated and expressed as ΔCTmax, ΔCTmean, ΔCVS and ΔAU, respectively. We then evaluated the relationship between ¹⁸F-NaF uptake (using the maximum target-to-background ratio, TBRmax, and the maximum blood-subtracted ¹⁸F-NaF activity, bsNaFmax, which was obtained by subtracting the SUVmax of each calcified plaque lesion and NaF-avid site from the SUVmean in the right atrium blood pool) and the change in calcified plaque volume and characteristics obtained after 1 year.

Results

We detected and analysed 182 calcified plaque sites and 96 hot spots on major vessel walls. ¹⁸F-NaF uptake showed very weak correlations with CTmax, CTmean, CVS, CVS after 1 year, AU and AU after 1 year on both baseline and follow-up PET/CT scans for each site. ¹⁸F-NaF uptake showed no correlation with ΔCTmax or ΔCTmean. However, there was a significant correlation between the intensity of ¹⁸F-NaF uptake and ΔCVS and ΔAU.

Conclusion

¹⁸F-NaF uptake has a strong correlation with calcium score progression which was a predictor of future cardiovascular disease risk. PET/CT using ¹⁸F-NaF may be able to predict calcium score progression which is known to be the major characteristic of atherosclerosis.

     

Disease-specific clinical problems associated with the subchondral bone

The subchondral bone is involved in a variety of diseases affecting both the articular cartilage and bone. Osteochondral defects in distinct locations and of variable sizes are the final results of different etiologies. These include traumatic osteochondral defects, osteochondritis dissecans, osteonecrosis, and osteoarthritis. Traumatic osteochondral defects are caused by osteochondral fractures, separating an osteochondral fragment that includes articular cartilage and both subchondral and trabecular bone from the joint surface. In osteochondritis dissecans, the disease originates in the subchondral bone and secondarily affects the articular cartilage. Location, stage, size, and depth of osteochondral lesions play a role in the treatment of traumatic osteochondral defects and osteochondritis dissecans. Surgical options include fragment refixation, transplantation of osteochondral autografts, or bone restoration by impacted cancellous bone grafts combined with autologous chondrocyte transplantation. An insufficiency fracture of the subchondral bone may be the initiating factor of what was formerly believed to be a spontaneous osteonecrosis of the knee (SPONK). Recent histopathological studies suggest that each stage of SPONK reflects different types of bone repair reactions following a fracture of the subchondral bone plate. Osteoarthritis is a disease that does affect not only the articular cartilage, but also the subchondral bone. Reconstructive surgical techniques aim at preserving joint function, inducing fibrocartilaginous repair, and at correcting malalignment. This review summarizes the current status of the clinical treatment of traumatic osteochondral defects, osteochondritis dissecans, osteonecrosis, and osteoarthritis as they affect the subchondral bone region and its adjacent structures.     

Prospective comparison of <Superscript>68</Superscript>Ga-PSMA PET/CT, <Superscript>18</Superscript>F-sodium fluoride PET/CT and diffusion weighted-MRI at for the detection of bone metastases in biochemically recurrent prostate cancer

Purpose

To prospectively compare diagnostic accuracies for detection of bone metastases by ⁶⁸Ga-PSMA PET/CT, ¹⁸F-NaF PET/CT and diffusion-weighted MRI (DW₆₀₀-MRI) in prostate cancer (PCa) patients with biochemical recurrence (BCR).

Methods

Sixty-eight PCa patients with BCR participated in this prospective study. The patients underwent ⁶⁸Ga-PSMA PET/CT, a ¹⁸F-NaF PET/CT and a DW₆₀₀-MRI (performed in accordance with European Society of Urogenital Radiology guidelines, with b values of 0 and 600 s/mm²). Bone lesions were categorized using a three-point scale (benign, malignant or equivocal for metastases) and a dichotomous scale (benign or metastatic) for each imaging modality by at least two experienced observers. A best valuable comparator was defined for each patient based on study-specific imaging, at least 12 months of clinical follow-up and any imaging prior to the study and during follow-up. Diagnostic performance was assessed using a sensitivity analysis where equivocal lesions were handled as non-metastatic and then as metastatic.

Results

Ten of the 68 patients were diagnosed with bone metastases. On a patient level, sensitivity, specificity and the area under the curve (AUC) by receiver operating characteristic analysis were, respectively, 0.80, 0.98–1.00 and 0.89–0.90 for ⁶⁸Ga-PSMA PET/CT (n?=?68 patients); 0.90, 0.90–0.98 and 0.90–0.94 for ¹⁸NaF PET/CT (n?=?67 patients); and 0.25–0.38, 0.87–0.92 and 0.59–0.62 for DW₆₀₀-MRI (n?=?60 patients). The diagnostic performance of DW₆₀₀-MRI was significantly lower than that of ⁶⁸Ga-PSMA PET/CT and ¹⁸NaF PET/CT for diagnosing bone metastases (p?<?0.01), and no significant difference in the AUC was seen between ⁶⁸Ga-PSMA PET/CT and ¹⁸NaF PET/CT (p?=?0.65).

Conclusion

⁶⁸Ga-PSMA PET/CT and ¹⁸F-NaF PET/CT showed comparable and high diagnostic accuracies for detecting bone metastases in PCa patients with BCR. Both methods performed significantly better than DW₆₀₀-MRI, which was inadequate for diagnosing bone metastases when conducted in accordance with European Society of Urogenital Radiology guidelines.

     

18F-FDG PET与99Tcm- MDP显像诊断肿瘤骨转移的比较

目的　研究1 8F 脱氧葡萄糖 (FDG)PET显像对肿瘤骨转移的诊断价值 ,并与99Tcm 亚甲基二膦酸盐 (MDP)骨显像比较。方法　 4 3例确诊的肿瘤患者在 1个月内先后行1 8F FDGPET及99Tcm MDP骨显像 ,其中 2 4例经其他检查及随访证实为骨转移。对比分析 2种显像结果。结果　 2 4例骨转移患者FDGPET显像均为阳性 ,骨显像阳性 2 2例 ,灵敏度分别为 10 0 %和 91.7% ,差异无显著性 (P >0 0 5 )。19例无骨转移患者中FDGPET显像阴性 18例 ,骨显像阴性 11例 ,特异性分别为 94 .7%和5 7 9% ,差异有显著性 (P <0 0 5 )。 2种方法检测骨转移的准确性分别为 97.7%和 76 .7% ,差异有显著性 (P <0 0 5 )。结论　1 8F FDGPET显像诊断肿瘤骨转移的灵敏度与99Tcm MDP骨显像无明显差别 ,但有更高的特异性和准确性。     

淋巴瘤骨髓浸润的18F-FDG PET显像研究

目的 用^18F-脱氧葡萄糖（FDG）PET显像研究淋巴瘤细胞骨髓浸润。方法 恶性淋巴癌患者30例，其中非霍奇金淋巴瘤（NHL）20例、霍奇金病（HD）10例，进行全身^18F-FDG PET显像。局灶性边缘清楚的淋巴结相应区域^18F-FDG浓聚视为恶性淋巴结显影。利用灰度色标，视觉分析骨髓及肝脏内^18F-FDG浓聚情况。骨髓的^18F-FDG分布不均，摄取高于肝脏，判断为骨髓^18F-FDG摄取异常；骨髓的^18F-FDG分布均匀，摄取低于或等于肝脏，判断为骨髓^18F-FDG摄取正常。所有患者均行髂棘的骨髓活组织检查。结果 30例中18例有淋巴结摄取^18F-FDG；12例淋巴结摄取^18F-FDG阴性患者中，8例NHL，4例HD。有26例患者的骨髓^18F-FDG摄取情况与骨髓组织学检查结果一致，其中骨髓有淋巴细胞浸润7例，无淋巴细胞浸润19例。有3例骨髓组织学检查阴性的患者，^18F-FDG PET示骨髓^18F-FDG摄取异常、骨髓有淋巴细胞浸润；1例NHL患者，骨髓组织学检查阳性但^18F-FDG PET示骨髓^18F-FDG摄取正常。结论 ^18F-DG PET全身显像能正确评价骨髓淋巴细胞浸润情况，减少对淋巴瘤分期所进行的骨髓组织学检查。     

The role of quantitative (18)F-FDG PET studies for the differentiation of malignant and benign bone lesions.

The role of quantitative (18)F-FDG PET studies for the differentiation of benign and malignant bone lesions is still an open question. METHODS: Our evaluation included 83 patients with 37 histologically proven malignancies and 46 benign lesions. Thirty-five of the 46 benign lesions were histologically confirmed. The (18)F-FDG studies were accomplished as a dynamic series for 60 min. Evaluation of the (18)F-FDG kinetics was performed using the following parameters: standardized uptake value (SUV), global influx (Ki), computation of the transport constants K1-k4 with consideration of the distribution volume (VB) according to a 2-tissue-compartment model, fractal dimension based on the box-counting procedure (parameter for the inhomogeneity of the tumors). RESULTS: The mean SUV, the vascular fraction VB, K1, and k3 were higher in malignant tumors compared with benign lesions (t test; P < 0.05). Although the (18)F-FDG SUV was helpful to differentiate benign and malignant tumors, there was some overlap, which limited the diagnostic accuracy. On the basis of the discriminant analysis, the SUV alone showed a sensitivity of only 54.05%, a specificity of 91.30%, and a diagnostic accuracy of 74.70%. The fractal dimension was superior and showed a sensitivity of 71.88%, a specificity of 81.58%, and an accuracy of 77.14%. The combination of SUV, fractal dimension, VB, K1-k4, and Ki revealed the best results with a sensitivity of 75.86%, a specificity of 97.22%, and an accuracy of 87.69%. Bayesian analysis showed true-positive results at the level of 0.8 for a low prevalence of disease (0.235) if the full kinetic data were used in the evaluation. CONCLUSION: (18)F-FDG PET has a high specificity for the exclusion of a malignant bone tumor. Evaluation of the full (18)F-FDG kinetics and the application of discriminant analysis are required and can be used prospectively to classify a bone lesion as malignant or benign.