Comparison of 18F-FDG PET/CT and 67Ga-SPECT for the diagnosis of fever of unknown origin: a multicenter prospective study in Japan

OBJECTIVE

The aim of this multicenter prospective study was to compare the sensitivity of ¹⁸F-fluorodeoxyglucose (FDG)-positron emission tomography/computed tomography (PET/CT) with that of ⁶⁷Ga single photon emission computed tomography (SPECT) for the identification of the site of greatest importance for the final diagnosis of the cause of fever of unknown origin (FUO).

METHODS

The study participants consisted of patients with an axillary temperature ≥ 38.0 °C on ≥ 2 occasions within 1 week, with repeated episodes for ≥ 2 weeks prior to providing consent, and whose final diagnosis after undergoing specific examinations, including a chest-to-abdomen CT scan, was uncertain. All the patients underwent FDG-PET/CT imaging first, followed by ⁶⁷Ga-SPECT imaging within 3 days. The results of the FDG-PET/CT and ⁶⁷Ga-SPECT examinations were reviewed by the central image interpretation committee (CIIC), which was blinded to all other clinical information. The sensitivities of FDG-PET/CT and ⁶⁷Ga-SPECT were then evaluated with regard to identifying the site of greatest importance for a final diagnosis of the cause of the fever as decided by the patient's attending physician. The clinical impacts (four grades) of FDG-PET/CT and ⁶⁷Ga-SPECT on the final diagnosis were evaluated.

RESULTS

A total of 149 subjects were enrolled in this study between October 2014 and September 2017. No adverse events were identified among the enrolled subjects. Twenty-one subjects were excluded from the study because of deviations from the study protocol. Among the 128 remaining subjects, a final diagnosis of the disease leading to the appearance of FUO was made for 92 (71.9%) subjects. The final diagnoses in these 92 cases were classified into four groups: noninfectious inflammatory disease (52 cases); infectious disease (31 cases), malignancy (six cases); and other (three cases). These 92 subjects were eligible for inclusion in the study's analysis, but one case did not meet the PET/CT image acquisition criteria; thus, PET/CT results were analyzed for 91 cases. According to the patient-based assessments, the sensitivity of FDG-PET/CT (45%, 95% CI 33.1-58.2%) was significantly higher than that for ⁶⁷Ga-SPECT (25%, 95% CI 15.5-37.5%) (P = 0.0029). The clinical impact of FDG-PET/CT (91%) was also significantly higher than that for ⁶⁷Ga-SPECT (57%, P < 0.001).

CONCLUSIONS

FDG-PET/CT showed a superior sensitivity to ⁶⁷Ga-SPECT for the identification of the site of greatest importance for the final diagnosis of the cause of FUO.

Correction: Band gap modification and photoluminescence enhancement of graphene nanoribbon filled single-walled carbon nanotubes

Correction for 'Band gap modification and photoluminescence enhancement of graphene nanoribbon filled single-walled carbon nanotubes' by A. I. Chernov et al., Nanoscale, 2018, DOI: 10.1039/c7nr07054c.

Band gap modification and photoluminescence enhancement of graphene nanoribbon filled single-walled carbon nanotubes

Molecule encapsulation inside the single-walled carbon nanotube (SWCNT) core has been demonstrated to be a successful route for the modification of nanotube properties. SWCNT diameter-dependent filling results in band gap modification together with the enhancement of photoluminescence quantum yield. However, the interaction between the inner structure and the outer shell is complex. It depends on the orientation of the molecules inside, the geometry of the host nanotube and on several other mechanisms determining the resulting properties of the hybrid nanosystem. In this work we study the influence of encapsulated graphene nanoribbons on the optical properties of the host single-walled carbon nanotubes. The interplay of strain and dielectric screening caused by the internal environment of the nanotube affects its band gap. The photoluminescence of the filled nanotubes becomes enhanced when the graphene nanoribbons are polymerized inside the SWCNTs at low temperatures. We show a gradual photoluminescence quenching together with a selective signal enhancement for exact nanotube geometries, specifically (14,6) and (13,8) species. A precise adjustment of the optical properties and an enhancement of the photoluminescence quantum yield upon filling for nanotubes with specific diameters were assigned to optimal organization of the inner structures.

The assessment of surgical and non-surgical treatment of stage II medication-related osteonecrosis of the jaw

Background

Non-surgical treatment has generally been recommended for stage II medication-related osteonecrosis of the jaw (MRONJ) in preference to surgery. However, non-surgical treatment is not empirically effective. The aim of this study was to evaluate whether surgical or non-surgical treatment leads to better outcomes for stage II MRONJ.

Material and Methods

In this retrospective study, surgery was performed in a total of 28 patients while 24 patients underwent non-surgical treatment. The outcomes of both treatment approaches after 6 months were evaluated and statistically compared. In addition, risk factors for surgical and non-surgical treatments were assessed for each.

Results

Surgical treatment in 25 patients (89.3%) resulted in success, with failure in 3 patients (10.7%). Non-surgical treatment was successful for 8 patients (33.3%) and failed in 16 patients (66.7%). There was therefore a significant difference between surgical and non-surgical treatment outcomes (P<0.01). Regarding risk factors, in non-surgical treatment primary diseases, medications, and drug holiday had a significant effect on outcomes (P<0.01). Risk factors for surgical treatment could not be clarified.

Conclusions

Surgical treatment is more effective than non-surgical treatment for stage II MRONJ, and drug holiday, primary disease, and medication constitute risk factors in non-surgical treatment.

Key words:Bisphosphonate, bisphosphonate-related osteonecrosis of the jaw, denosumab, management, medication-related osteonecrosis of the jaw.

Evaluation of a new motion correction algorithm in PET/CT: combining the entire acquired PET data to create a single three-dimensional motion-corrected PET/CT image

PURPOSE

This study evaluated the potential of Q.Freeze algorithm for reducing motion artifacts, in comparison with ungated imaging (UG) and respiratory-gated imaging (RG).

PATIENTS AND METHODS

Twenty-nine patients with 53 lesions who had undergone RG F-FDG PET/CT were included in this study. Using PET list mode data, five series of PET images [UG, RG, and QF images with an acquisition duration of 3 min (QF3), 5 min (QF5), and 10 min (QF10)] were reconstructed retrospectively. The image quality was evaluated first. Next, quantitative metrics [maximum standardized uptake value (SUVmax), mean standardized uptake value (SUVmean), SD, metabolic tumor volume, signal to noise ratio, or lesion to background ratio] were calculated for the liver, background, and each lesion, and the results were compared across the series.

RESULTS

QF10 and QF5 showed better image quality compared with all other images. SUVmax in the liver, background, and lesions was lower with QF10 and QF5 than with the others, but there were no statistically significant differences in SUVmean and the lesion to background ratios. The SD with UG and RG was significantly higher than that with QF5 and QF10. The metabolic tumor volume in QF3 and QF5 was significantly lower than that in UG.

CONCLUSION

The Q.Freeze algorithm can improve the quality of PET imaging compared with RG and UG.

Accumulation of accident-derived radiocesium in lake and coastal sediments at 300-700 km distance from Fukushima area

The accumulation of accident-derived radiocesium was investigated in nine water bodies located 300-700 km from the Fukushima Dai-ichi Nuclear Power Plant (FDNPP). (134)Cs from the accident was detected in surface sediment of five water bodies. The (134)Cs concentration, corrected to the time of the accident in 2011, was generally lower than that of (137)Cs, and its spatial pattern does not fully correspond to that of (137)Cs. These results suggest that radiocesium derived from both FDNPP and past global fallout can be separately observed and that the contributions of both sources are non-uniform within these sites. The (134)Cs inventory in surface sediments is smaller than its deposition, suggesting that almost all deposited (134)Cs remains within the catchment and/or a part has been discharged from the saline and brackish water bodies.

High-temperature superconductivity in potassium-coated multilayer FeSe thin films

The recent discovery of possible high-temperature (T(c)) superconductivity over 65 K in a monolayer FeSe film on SrTiO3 (refs 1-6) triggered a fierce debate on how superconductivity evolves from bulk to film, because bulk FeSe crystal exhibits a T(c) of no higher than 10 K (ref. 7). However, the difficulty in controlling the carrier density and the number of FeSe layers has hindered elucidation of this problem. Here, we demonstrate that deposition of potassium onto FeSe films markedly expands the accessible doping range towards the heavily electron-doped region. Intriguingly, we have succeeded in converting non-superconducting films with various thicknesses into superconductors with T(c) as high as 48 K. We also found a marked increase in the magnitude of the superconducting gap on decreasing the FeSe film thickness, indicating that the interface plays a crucial role in realizing the high-temperature superconductivity. The results presented provide a new strategy to enhance and optimize T(c) in ultrathin films of iron-based superconductors.

Differentiation of Brain Tumor Recurrence from Post-Radiotherapy Necrosis with 11C-Methionine PET: Visual Assessment versus Quantitative Assessment

Purpose

The aim of this multi-center study was to assess the diagnostic capability of visual assessment in L-methyl-¹¹C-methionine positron emission tomography (MET-PET) for differentiating a recurrent brain tumor from radiation-induced necrosis after radiotherapy, and to compare it to the accuracy of quantitative analysis.

Methods

A total of 73 brain lesions (glioma: 31, brain metastasis: 42) in 70 patients who underwent MET-PET were included in this study. Visual analysis was performed by comparison of MET uptake in the brain lesion with MET uptake in one of four regions (around the lesion, contralateral frontal lobe, contralateral area, and contralateral cerebellar cortex). The concordance rate and logistic regression analysis were used to evaluate the diagnostic ability of visual assessment. Receiver-operating characteristic curve analysis was used to compare visual assessment with quantitative assessment based on the lesion-to-normal (L/N) ratio of MET uptake.

Results

Interobserver and intraobserver κ-values were highest at 0.657 and 0.714, respectively, when assessing MET uptake in the lesion compared to that in the contralateral cerebellar cortex. Logistic regression analysis showed that assessing MET uptake in the contralateral cerebellar cortex with brain metastasis was significantly related to the final result. The highest area under the receiver-operating characteristic curve (AUC) with visual assessment for brain metastasis was 0.85, showing no statistically significant difference with L/Nmax of the contralateral brain (AUC = 0.89) or with L/Nmean of the contralateral cerebellar cortex (AUC = 0.89), which were the areas that were the highest in the quantitative assessment. For evaluation of gliomas, no specific candidate was confirmed among the four areas used in visual assessment, and no significant difference was seen between visual assessment and quantitative assessment.

Conclusion

The visual assessment showed no significant difference from quantitative assessment of MET-PET with a relevant cut-off value for the differentiation of recurrent brain tumors from radiation-induced necrosis.

Assessment of the accuracy of plasma shape reconstruction by the Cauchy condition surface method in JT-60SA

For the purpose of stable plasma equilibrium control and detailed analysis, it is essential to reconstruct an accurate plasma boundary on the poloidal cross section in tokamak devices. The Cauchy condition surface (CCS) method is a numerical approach for calculating the spatial distribution of the magnetic flux outside a hypothetical surface and reconstructing the plasma boundary from the magnetic measurements located outside the plasma. The accuracy of the plasma shape reconstruction has been assessed by comparing the CCS method and an equilibrium calculation in JT-60SA with a high elongation and triangularity of plasma shape. The CCS, on which both Dirichlet and Neumann conditions are unknown, is defined as a hypothetical surface located inside the real plasma region. The accuracy of the plasma shape reconstruction is sensitive to the CCS free parameters such as the number of unknown parameters and the shape in JT-60SA. It is found that the optimum number of unknown parameters and the size of the CCS that minimizes errors in the reconstructed plasma shape are in proportion to the plasma size. Furthermore, it is shown that the accuracy of the plasma shape reconstruction is greatly improved using the optimum number of unknown parameters and shape of the CCS, and the reachable reconstruction errors in plasma shape and locations of strike points are within the target ranges in JT-60SA.

Combination chemotherapy with bevacizumab and S-1 for elderly patients with metastatic colorectal cancer (BASIC trial)

BACKGROUND

Chemotherapeutic regimens for elderly patients with metastatic colorectal cancer (mCRC), such as bevacizumab combined with 5-fluorouracil (5-FU) and leucovorin, often exclude oxaliplatin and irinotecan owing to the risk of toxicity. However, treatment with infusional 5-fluorouracil and leucovorin requires percutaneous port-catheter placement and other precautions, causing unnecessary stress for patients as well as healthcare workers.

METHODS

We conducted a phase II study to evaluate the efficacy and safety of bevacizumab plus S-1 in elderly patients with previously untreated mCRC. Bevacizumab was given intravenously every two weeks, and S-1 was administered orally on days 1-28 of a 42-day cycle. The primary end-point was progression-free survival (PFS). The secondary end-points were time to treatment failure, response rate (RR), overall survival (OS), treatment completion status and safety.

RESULTS

From October 2007 through March 2010, 56 patients were enroled. The median PFS was 9.9months, the median OS was 25.0months, and the RR was 57%. The main adverse events of grade 3 or higher were hypertension (11%), diarrhoea (9%) and neutropenia (7%).

CONCLUSION

Our results suggest that combination chemotherapy with S-1 and bevacizumab can be administered safely and continuously on an outpatient basis and is therapeutically effective in elderly patients with mCRC.

Reconstruction of band structure induced by electronic nematicity in an FeSe superconductor

We have performed high-resolution angle-resolved photoemission spectroscopy on an FeSe superconductor (T_{c}∼8  K), which exhibits a tetragonal-to-orthorhombic structural transition at T_{s}∼90  K. At low temperature, we found splitting of the energy bands as large as 50 meV at the M point in the Brillouin zone, likely caused by the formation of electronically driven nematic states. This band splitting persists up to T∼110  K, slightly above T_{s}, suggesting that the structural transition is triggered by the electronic nematicity. We have also revealed that at low temperature the band splitting gives rise to a van Hove singularity within 5 meV of the Fermi energy. The present result strongly suggests that this unusual electronic state is responsible for the unconventional superconductivity in FeSe.