Chest CT is thought to be sensitive but less specific in diagnosing the 2019 coronavirus disease (COVID-19). The diagnostic value of CT is unclear. We aimed to compare the performance of CT and ...initial RT-PCR for clinically suspected COVID-19 patients outside the epicentre—Wuhan, China.
Patients clinically suspected of COVID-19 infection who underwent initial RT-PCR and chest CT at the same time were retrospectively enrolled. Two radiologists with specific training reviewed the CT images independently and final diagnoses of the presence or absence of COVID-19 was reached by consensus. With serial RT-PCR as reference standard, the performance of initial RT-PCR and chest CT was analysed. A strategy of combining initial RT-PCR and chest CT was analysed to study the additional benefit.
82 patients admitted to hospital between Jan 10, 2020 to Feb 28, 2020 were enrolled. 34 COVID-19 and 48 non-COVID-19 patients were identified by serial RT-PCR. The sensitivity, specificity was 79% (27/34) and 100% (48/48) for initial RT-PCR and 77% (26/34) and 96% (46/48) for chest CT. The image readers had a good interobserver agreement with Cohen's kappa of 0.69. No statistical difference was found in the diagnostic performance between initial RT-PCR and chest CT. The comprehensive strategy had a higher sensitivity of 94% (32/34).
Initial RT-PCR and chest CT had comparable diagnostic performance in identification of suspected COVID-19 patients outside the epidemic center. To compensate potential risk of false-negative PCR, chest CT should be applied for clinically suspected patients with negative initial RT-PCR.
•Well trained radiologist has good specificity for COVID-19 in clinical setting.•Sensitivity of CT for suspected COVID-19 is lower than those in the epidemic center.•Chest CT may compensate false-negative initial RT-PCR.•Chest CT should be applied with RT-PCR for clinically suspected COVID-19, especially when initial RT-PCR is negative.
Amide proton transfer‐weighted (APTw) MR imaging shows promise as a biomarker of brain tumor status. Currently used APTw MRI pulse sequences and protocols vary substantially among different ...institutes, and there are no agreed‐on standards in the imaging community. Therefore, the results acquired from different research centers are difficult to compare, which hampers uniform clinical application and interpretation. This paper reviews current clinical APTw imaging approaches and provides a rationale for optimized APTw brain tumor imaging at 3 T, including specific recommendations for pulse sequences, acquisition protocols, and data processing methods. We expect that these consensus recommendations will become the first broadly accepted guidelines for APTw imaging of brain tumors on 3 T MRI systems from different vendors. This will allow more medical centers to use the same or comparable APTw MRI techniques for the detection, characterization, and monitoring of brain tumors, enabling multi‐center trials in larger patient cohorts and, ultimately, routine clinical use.
Objectives
To evaluate the performance of velocity-selective (VS) ASL among patients with untreated gliomas by comparing with both pseudo-continuous (PC) ASL and dynamic susceptibility ...contrast-enhanced perfusion-weighted imaging (DSC-PWI).
Methods
Forty-four consecutive patients with newly diagnosed glioma who underwent preoperative perfusion MRI including VSASL, PCASL, and DSC-PWI between 2017 and 2019 were retrospectively evaluated. Visual inspection was performed to evaluate the tumor signal intensity relative to gray matter based on 1–5 score criteria and weighted kappa was used to evaluate the pair-wise concordance between VSASL or PCASL and DSC-PWI. The relative tumor blood flow (rTBF) was measured from sampling intra-tumoral areas of hot-spot on the blood flow map and normalized against the contralateral normal gray matter blood flow. Linear regression and Bland–Altman analyses were performed to evaluate the correlation and agreement of rTBF measurements between ASL methods and DSC-PWI. The ROC analysis was constructed to determine the diagnostic performance of three perfusion methods for grading gliomas.
Results
TBF maps derived from VSASL were more comparable with DSC-PWI than PCASL on visual inspection (weighted kappa of 0.90 vs 0.68). In quantitative analysis, VSASL-rTBF yielded higher correlation with the values from DSC-PWI than PCASL-rTBF (
R
2
= 80% vs 47%,
p
< 0.001 for both). Both ASL and DSC-derived rTBF showed good distinction between low-grade and high-grade gliomas (
p
< 0.001). Compared to PCASL, VSASL yielded superior diagnostic sensitivity, specificity, and accuracy in glioma grading.
Conclusions
VSASL showed great promise for accurate quantification of TBF and could potentially improve the diagnostic performance of ASL in preoperative grading of gliomas.
Key Points
•
VSASL demonstrated a greater agreement with DSC-PWI than with PCASL on visual inspection and perfusion quantification
.
•
VSASL showed a higher diagnostic sensitivity, negative predictive value, and accuracy than PCASL for glioma grading
.
•
With the advantages of insensitivity to transit delay and no need of prescribing a labeling plane, VSASL could potentially improve the diagnostic performance of ASL for a more accurate, noninvasive quantification of TBF in patients with glioma
.
It remains difficult to distinguish tumor recurrence from radiation necrosis after brain tumor therapy. Here we show that these lesions can be distinguished using the amide proton transfer (APT) ...magnetic resonance imaging (MRI) signals of endogenous cellular proteins and peptides as an imaging biomarker. When comparing two models of orthotopic glioma (SF188/V+ glioma and 9L gliosarcoma) with a model of radiation necrosis in rats, we could clearly differentiate viable glioma (hyperintense) from radiation necrosis (hypointense to isointense) by APT MRI. When we irradiated rats with U87MG gliomas, the APT signals in the irradiated tumors had decreased substantially by 3 d and 6 d after radiation. The amide protons that can be detected by APT provide a unique and noninvasive MRI biomarker for distinguishing viable malignancy from radiation necrosis and predicting tumor response to therapy.
Amide proton transfer (APT) imaging is a novel MRI technique, in which the amide protons of endogenous proteins and peptides are irradiated to accomplish indirect detection using the bulk water ...signal. In this paper, the APT approach was added to a standard brain MRI protocol at 3T, and twelve patients with high-grade gliomas confirmed by histopathology were scanned. It is shown that all tumors, including one with minor gadolinium enhancement, showed heterogeneous hyperintensity on the APT images. The average APT signal intensities of the viable tumor cores were significantly higher than those of peritumoral edema and normal-appearing white matter (P<0.001). The average APT signal intensities were significantly lower in the necrotic regions than in the viable tumor cores (P=0.004). The APT signal intensities of the cystic cavities were similar to those of the viable tumor cores (P>0.2). The initial results show that APT imaging at the protein and peptide level may enhance non-invasive identification of tissue heterogeneity in high-grade brain tumors.
Objectives
To show the ability of using the amide proton transfer-weighted (APTW) MRI signals as imaging biomarkers to differentiate primary central nervous system lymphomas (PCNSLs) from high-grade ...gliomas (HGGs).
Methods
Eleven patients with lymphomas and 21 patients with HGGs were examined. Magnetization-transfer (MT) spectra over an offset range of ±6 ppm and the conventional MT ratio (MTR) at 15.6 ppm were acquired. The APTW signals, total chemical-exchange-saturation-transfer signal (integral between 0 and 5 ppm, CEST
total
), and MTR signal were obtained and compared between PCNSLs and HGGs. The diagnostic performance was assessed with the receiver operating characteristic (ROC) curve analysis.
Results
The PCNSLs usually showed more homogeneous APTW hyperintensity (spatially compared to normal brain tissue) than the HGGs. The APTW
max
, APTW
max-min
and CEST
total
signal intensities were significantly lower (
P
< 0.05, 0.001 and 0.05, respectively), while the APTW
min
and MTR were significantly higher (both
P
< 0.01) in PCNSL lesions than in HGG lesions. The APTW values in peritumoral oedema were significantly lower for PCNSLs than for HGGs (
P
< 0.01). APTW
max-min
had the highest area under the ROC curve (0.963) and accuracy (94.1 %) in differentiating PCNSLs from HGGs.
Conclusions
The protein-based APTW signal would be a valuable MRI biomarker by which to identify PCNSLs and HGGs presurgically.
Key Points
•
PCNSLs overall showed more homogeneous APTW hyperintensity than HGGs
.
•
Maximum APTW signals were lower in PCNSL lesions than in HGG lesions
.
•
MTR signals were higher in PCNSLs than in HGGs
.
•
APTW heterogeneity had the highest accuracy in differentiating PCNSLs from HGGs
.
The purpose of this work was to investigate the diagnostic performance of amide proton transfer‐weighted (APTW) and intravoxel incoherent motion (IVIM) magnetic resonance imaging (MRI) in the ...preoperative grading of gliomas. Fifty‐one patients with suspected gliomas were recruited and underwent a preoperative MRI examination that included APTW and IVIM sequences. All cases were confirmed by postsurgical histopathology. APTW signal intensity, true diffusion coefficient (D), perfusion fraction (f) and pseudo‐diffusion coefficient (D*) were applied to assess the solid tumor component and contralateral normal‐appearing white matter. The relative APTW signal intensity (rAPTW) was also used. Independent‐sample and paired‐sample t‐tests were used to compare differences in MRI parameters between low‐grade glioma (LGG) and high‐grade glioma (HGG) groups. The diagnostic performance was assessed with the receiver operating characteristic curve. Twenty‐six patients were pathologically diagnosed with LGG and 25 were diagnosed with HGG. APTW, rAPTW and f values were significantly higher (all p < 0.001), whereas D values were significantly lower (p < 0.001) in the HGG group than in the LGG group. There was no significant difference between D* values for the two groups. rAPTW had an area under the curve (AUC) of 0.957, with a sensitivity of 100% and a specificity of 84.6%, followed by APTW, f, D and D*. The combined use of APTW and IVIM showed the best diagnostic performance, with an AUC of 0.986. In conclusion, APTW and IVIM, as two promising supplementary sequences for routine MRI, could be valuable in differentiating LGGs from HGGs.
Amide proton transfer‐weighted (APTW) imaging can generate image contrast mainly related to endogenous cellular proteins in tissue, and intravoxel incoherent motion (IVIM) magnetic resonance imaging (MRI) can separate water molecular diffusion from microcirculation. Fifty‐one patients with glioma were recruited to investigate the diagnostic performance of APT and IVIM MRI. Our results show that these supplementary MRI methods are valuable in differentiating low‐ from high‐grade glioma.
PURPOSE We aimed to evaluate the diagnostic accuracy and safety profile of computed tomography (CT)-guided percutaneous transthoracic needle biopsy (PTNB) in patients with primary malignancy ...suspected of lung metastasis and assess possible factors associated with nondiagnostic results. METHODS All PTNBs with core needle performed in our hospital from January 2014 to January 2019 were retrospectively reviewed. Overall, 108 cases were found to have a history of primary malignancy with suspected lung metastasis. Patient demographics, lesion characteristics, procedure techniques and complications were evaluated as predictors of overall diagnosis, final diagnosis of lung metastasis, and nondiagnostic results. Statistical analysis was performed using univariate analysis. RESULTS The overall diagnostic accuracy of PTNB was 83.3%. Lung metastasis was found in 52.8% of PTNBs (57 of 108) and nondiagnostic results were present in 27.6% (18 of 108). Of the 18 cases with nondiagnostic results, 11 cases had a final diagnosis of lung metastasis (61.1%), yielding PTNB a sensitivity of 83.8% and specificity of 100% for the detection of lung metastasis. Smaller lesion size (p = 0.014), pneumothorax (p = 0.026), and hemoptysis (p = 0.014) were significantly associated with overall nondiagnostic results. Similarly, smaller lesion size (p = 0.047), pneumothorax (p = 0.019), high-grade pulmonary hemorrhage (p = 0.019), and hemoptysis (p = 0.012) were significantly correlated with unsuccessful biopsies in the diagnosis of lung metastasis. CONCLUSION CT-guided core needle biopsy of the lung in patients with primary malignancy suspected of lung metastasis has a high diagnostic accuracy with acceptable complication rates. Small lesion size, pneumothorax, high-grade pulmonary hemorrhage, and hemoptysis are significantly associated with nondiagnostic results in the final diagnosis of lung metastasis. Repeat biopsy and clinical/radiological follow-up should be considered in cancer patients with nondiagnostic results due to the high probability of lung metastasis.
Osteoarthritis (OA) is the commonest musculoskeletal disease worldwide, with an increasing prevalence due to aging. It causes joint pain and disability, decreased quality of life, and a huge burden ...on healthcare services for society. However, the current main diagnostic methods are not suitable for early diagnosing patients of OA. The use of machine learning (ML) in OA diagnosis has increased dramatically in the past few years. Hence, in this review article, we describe the research progress in the application of ML in the early diagnosis of OA, discuss the current trends and limitations of ML approaches, and propose future research priorities to apply the tools in the field of OA. Accurate ML-based predictive models with imaging techniques that are sensitive to early changes in OA ahead of the emergence of clinical features are expected to address the current dilemma. The diagnostic ability of the fusion model that combines multidimensional information makes patient-specific early diagnosis and prognosis estimation of OA possible in the future.
PDF
