A new index for assessing cerebral ventricular volume in idiopathic normal-pressure hydrocephalus: a comparison with Evans' index.

PURPOSE: To recommend a new simple and explicit index termed the anteroposterior diameter of the lateral ventricle index (ALVI) for assessing brain ventricular size in neuroimaging and to compare Evans index (EI) between idiopathic normal pressure hydrocephalus (iNPH) patients and age-matched healthy elderly subjects. METHODS: Retrospective measurements of ventricular volume (VV), relative VV (RVV), the EI, and the ALVI were taken from thin-section CT scans for 23 pre-shunt-insertion iNPH patients and 62 age-matched healthy elderly volunteers. The area under the receiver operating characteristic (ROC) curve (AUC), net reclassification improvement (NRI), and integrated discrimination improvement (IDI) were calculated to assess the effectiveness of ALVI scores for predicting VV. RESULTS: The correlations between VV or RVV and ALVI scores (VV, r = 0.957; RVV, r = 0.983) were significantly stronger than the corresponding correlations with EI scores (VV, r = 0.843; RVV, r = 0.840). The AUC for ALVI scores was significantly greater than the AUC for EI scores. Furthermore, with the inclusion of the ALVI, the NRI value was 0.14 and the IDI value was 0.14; these improvements were also statistically significant. CONCLUSION: The ALVI is a more accurate and more explicitly defined marker of VV than the EI and assesses ventricular enlargement effectively. We suggest that ventricular enlargement of the healthy elderly be defined by ALVI > 0.50.

Coronary Computed Tomography (CT) Angiography Characteristics of High-Risk Plaque: Correlation with Stress Myocardial Perfusion Imaging in Patients with Moderate Coronary Stenosis.

BACKGROUND The aim of this study was to investigate the ability of coronary computed tomographic angiography (CCTA) characteristics of high-risk plaque (HRP) in moderate stenosis to improve differentiation of myocardial ischemia detected by stress CT perfusion (CTP) imaging. MATERIAL AND METHODS Sixty-two patients with coronary plaques and moderate stenosis confirmed by invasive coronary angiography (ICA) had stress CTP and 26 of these patients were found to have myocardial ischemia. The other 36 patients without myocardial ischemia were defined as controls. Characteristics of major plaques on CCTA images of the ischemia and non-ischemia groups were analyzed and compared. RESULTS Differences between the 2 groups were observed in plaque volume, burden and rough inner surface necrotic core volume, plaque-lipid interface and plaque length. In a multivariable analysis, plaque burden and necrotic core volume were significantly associated with myocardial ischemia: plaque burden odds ratio (OR) was 1.28 (95% confidence interval [CI], 1.12-1.48); necrotic core volume OR was 1.78 (95% CI, 1.03-1.34). Compared with other quantitative measurements, optimized thresholds for plaque burden (area under the curve was 0.852) and necrotic core volume (area under the curve was 0.730) showed significantly higher diagnostic performance for ischemia with threshold values of 60.8% and 11.25 mm³, respectively. CONCLUSIONS CCTA characteristics of major plaques may improve the discrimination of ACS patients with myocardial ischemia on stress CTP.

Morphological classification of pre-invasive lesions and early-stage lung adenocarcinoma based on CT images.

OBJECTIVE: To retrospectively analyze the computed tomography (CT) features in patients with pre-invasive lesions and early-stage lung adenocarcinoma and to explore the correlation between tumor morphological changes and pathological diagnoses. MATERIALS AND METHODS: CT morphological characteristics in 2106 patients with pre-invasive (stage 0) and early-stage (stage I) lung adenocarcinoma were analyzed; lesions were confirmed by surgical pathology. Based on the morphological characteristics, the lesions were divided into eight types: I (cotton ball, ground-glass nodules), II (solid fill), III (granular), IV (dendriform), V (bubble-like lucencies), VI (alveolate or honeycomb), VII (scar-like), and VIII (notched or umbilication). The different distributions of eight morphological types in pathological types of the lesions and subtypes of invasive adenocarcinoma were analyzed by chi-squared or Fisher's exact test. Correlation between the percentage of ground-glass opacity in the lesions and pathology types were analyzed by two-tailed Pearson's test. RESULTS: A negative correlation was observed between the pathological types and proportion of ground-glass component in the lesions (p < 0.001 and r = - 0.583). Significant differences in morphological characteristics among various pathological types of pre-invasive lesions and early lung adenocarcinomas were observed (p < 0.05). Furthermore, among the different pathological subtypes of stage I invasive adenocarcinoma, the differences in their manifestation as morphological types I, II, III, and VI were statistically significant (p < 0.05). CONCLUSION: The eight types of morphological classification of pre-invasive lesions and early-stage (stage 0 or stage I) lung adenocarcinoma has different pathological bases, and morphological classification may be useful for the diagnosis and differential diagnosis of lung adenocarcinoma. KEY POINTS: • CT morphological classification of pre-invasive lesions and lung adenocarcinoma is intuitive. • CT morphological classification characterizes morphological changes of the entire lesion. • Different pathological types of lung adenocarcinoma have different morphological features.

Surveillance Magnetic Resonance Imaging in Detecting the Second Breast Cancer in Women With a Personal History of Breast Cancer.

OBJECTIVE: The objective of this study was to evaluate the diagnostic performance of magnetic resonance imaging (MRI) in detecting the secondary breast cancer among women with a personal history of the lesion. MATERIALS AND METHODS: We retrospectively reviewed breast MRI examinations performed between 2007 and 2011. A total of 798 women with a history of breast cancer were included in the study. Cancer detection rate, positive predictive value (PPV), recall rate, sensitivity, and specificity were assed. Cancer detection rate was stratified by interval after surgery of the primary breast cancer. Also, we derived 1 comparison group from the women for comparing the performance of x-ray mammography, ultrasound, and MRI in detecting the second breast cancer. RESULTS: Of the 798 patients, 47 of the 49 secondary breast carcinomas were detected by MRI. The sensitivity and specificity of MRI in detecting the secondary lesions were 95.9% and 96.3%, respectively. The recall rate was 9.5%, and the PPV was 61.8%. Cancer detection rate of MRI examinations performed at more than 36 months after initial surgery was significantly higher than that at 36 months or less after initial surgery (13.7% vs 3.6, P < 0.001). In comparison group, the sensitivity and specificity of MRI, mammography, and ultrasound were 96.7% and 96.1%, 48.4% and 93.9%, and 77.4% and 96.1%, respectively. CONCLUSIONS: Surveillance MRI for women with a personal history of breast cancer has high sensitivity in finding the secondary malignancies with a reasonable recall rate and PPV.

Dual-Energy Computed Tomography-Based Iodine Quantitation for Response Evaluation of Lung Cancers to Chemoradiotherapy/Radiotherapy: A Comparison With Fluorine-18 Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography-Based Positron Emission Tomography/Computed Tomography Response Evaluation Criterion in Solid Tumors.

OBJECTIVE: The objective of this study was to investigate the correlation between dual-energy computed tomography (DECT)-based iodine quantitation and fluorine-18 fluorodeoxyglucose (F-FDG) positron emission tomography (PET)/computed tomography (CT) imaging for response evaluation of lung cancers to treatment. METHODS: In this prospective study, a total of 32 pairs of DECT and F-FDG PET/CT imaging acquired consecutively from 13 patients with primary or metastatic lung cancers receiving either radiotherapy alone or chemoradiotherapy were analyzed. Imaging examinations were performed before, immediately, and no later than 6 months after treatment for response evaluation. Iodine-related parameters including the total iodine uptake (TIU) and vital volume (VIV) from DECT and metabolic metrics such as the standardized uptake value normalized to lean body mass (SULpeak), metabolic tumor volume (MTV), and the total lesion glycolysis (TLG) from F-FDG-PET/CT were generated and measured by semiautomatic approaches. Dual-energy CT and PET/CT metrics were calculated and followed up with comparison with response evaluation criteria in solid tumors (RECIST). RESULTS: Analysis of pretreatment imaging data revealed a strong correlation between DECT metrics (RECIST, TIU, and VIV) and F-FDG PET/CT metrics (MTV, TLG) with coefficients of R ranging from 0.86 to 0.90 (P < 0.01). With the delivery of treatment, all measured DECT and PET/CT metrics significantly decreased whereas the descending amplitude in RECIST was significantly smaller than that of the remaining parameters (P < 0.05). During follow-up examinations, both metrics followed a similar changing pattern. Overall, strong consistency was found between RECIST, TIU, VIV and SULpeak, MTV, TLG (R covers 0.78-0.96, P < 0.05). CONCLUSIONS: Semiautomatic iodine-related quantitation in DECT correlated well with metabolism-based measurements in F-FDG PET/CT, suggesting that DECT-based iodine quantitation might be a feasible substitute for assessment of lung cancer response to chemoradiotherapy/radiotherapy with comparison with F-FDG PET/CT.

Spectral CT imaging of intranodular hemorrhage in cases with challenging benign thyroid nodules.

While conventional ultrasound and laboratory testing can differentiate most thyroid conditions and malignancies, spectral dual-energy computed tomography (DECT) provides molecular data potentially useful in differential diagnosis of small, complex, and partially obscured hemorrhaged nodules with recent bleeding. To demonstrate that Gemstone Spectral Imaging (GSI) analysis of DECT data differentiates challenging benign thyroid nodule conditions in patients with intranodular hemorrhages. A retrospective study was conducted of 30 intranodular hemorrhage patients from 2010 to 2013, including 18 that underwent surgery and provided thyroid tissues for prospective histological analysis. Iodine and water content were determined in patient CT scans and ex vivo tissue specimen scans by reconstruction of raw CT data at 65 keV (optimal contrast). Slope of spectral curve (λ HU), effective atomic number (Z eff), and final pathological diagnosis were recorded. Iodine content, water content, Z eff, and λ HU significantly varied by region (intranodular hemorrhage, solid thyroid nodule, and adjacent margins) in patients and tissue specimens (P < 0.05). Intranodular hemorrhage exhibited elevated water concentrations (~1100 mg/mL), suggesting a practical threshold of 1075 mg/mL for differentiating intra-plaque hemorrhage and solid nodular regions. Spectral CT provided diagnostic information in 14 thyroid adenomas and four goiters (histologically confirmed in donor specimens), and eight thyroid adenomas and four nodular goiters based on clinical diagnosis. Diagnostically useful regional characteristic of intranodular hemorrhage in the thyroid was visualized via spectral CT employing material decomposition, potentially yielding additional molecular data about complex lesion characteristics no apparent in conventional imaging or laboratory methods.

Diagnosis of Dissection of the Coronary Artery Dissection by Multidetector Computed Tomography: A Comparative Study With Coronary Angiology.

OBJECTIVES: This study was to assess the diagnostic performance of multidetector computed tomography (MDCT) angiographic protocol for dissection of the coronary artery (DCA) detection compared with coronary angiology (CAG). METHODS: Intravascular ultrasound was used as the gold standard for DCA diagnosis. Thirty-six DCA patients and 34 non-DCA (control) participants were retrospectively reviewed. The CAG and MDCT angiography images were separately reviewed by 4 independent observers, and a 5-point grading scale was used for DCA diagnosis. Diagnostic performance was compared using receiver operating characteristic analysis. Sensitivity, specificity, and negative predictive values were calculated. RESULTS: The MDCT performed significantly better than that of CAG (AZ = 0.9943 ± 0.0034 vs AZ = 0.8411 ± 0.0274, respectively) for DCA detection. The sensitivity (98.6%), specificity (89.7%), and negative predictive value (98.4%) of MDCT for DCA were higher than those of CAG (77.8%, 79.4%, and 77.1%, respectively). CONCLUSIONS: Multidetector computed tomography angiography was a more sensitive and specific technique for the diagnosis of DCA compared with CAG.

Ultrashort echo time bi-component analysis of cortical bone--a field dependence study.

PURPOSE: The purpose of this study is to investigate the effect of differing field strength on the T2* of cortical bone at 1.5 T and 3 T. METHODS: Ultrashort echo time pulse sequences were used to study six bovine and nine human bone samples at 1.5 T and 3 T using single- and bi-component T2* analysis. RESULTS: On average, the bound water T2* of bovine bone decreased by 16% (from 0.32 ms at 1.5 T to 0.27 ms at 3 T, P < 0.01) and the bound water T2* of human bone decreased by 21% (from 0.42 ms at 1.5 T to 0.33 ms at 3 T, P < 0.01) at the higher field strength. The free water T2* of bovine bone decreased by 50% (from 4.23 ms at 1.5 T to 2.12 ms at 3 T, P < 0.001) and the free water T2* of human bone decreased by 68% (from 7.65 ms at 1.5 T to 2.46 ms at 3 T, P < 0.001) at the higher field strength. Bound and free water fractions showed only minor change with field strength in bovine (< 2%, P > 0.05) and human bone (< 4%, P > 0.05). CONCLUSION: Ultrashort echo time bi-component analysis provides consistent bound and free water fractions at 1.5 T and 3 T, thereby allowing field-independent comparisons.

[CT diagnosis of different pathological types of ground-glass nodules].

OBJECTIVE: To explore the CT features of ground-glass nodules (GGN) including preinvasive lesions [atypical adenomatous hyperplasia (AAH) and adenocarcinoma in situ (AIS)], minimally invasive adenocarcinoma (MIA) and invasive adenocarcinoma (IAC). METHODS: Ninety-seven GGN lesions confirmed by operation pathology were included in this study. The lesions were divided into three groups: preinvasive lesion group (24 cases), MIA group (39 cases), IAC group (34 cases). The lesion size, 3-dimensional ratio, 2-dimensional ratio in axial images, lesion density, shape, speculation, lobulation, air-containing space and pleural indentation on the preoperative CT images in the three groups were analyzed and compared with pathological results. The data were statistically analyzed using SPSS 17.0. RESULTS: All preinvasive lesions presented as pure GGN on CT image, most showed round-like shape, clear and smooth border. MIA presented as pure GGN or mixed GGN on CT image, most showed round-like shape, with a clear and smooth border. IAC most presented as mixed GGN on CT image, often showed irregular shape. Speculation, lobulation, air-containing space and pleural indentation displayed gradually increasing from preinvasive lesions to MIA and IAC. There were statistically significant differences in lesion size, CT density, shape, air-containing space, speculation, pleural indentation and long diameter of solid component between the MIA and IAC groups (P < 0.05 for all). There were statistically significant differences in CT density values and long diameters of solid component of the lesions between the preinvasive lesion group and MIA group (P < 0.05). The AUC of solid component of the preinvasive lesion group and MIA group was 0.705, and that of the MIA and IAC groups was 0.814. CONCLUSION: Comprehensive analysis of the CT image features of GGNs, especially the solid component in the lesions, may help to the preoperative and differential diagnosis of preinvasive lesions, MIA and IAC.

[Imaging origins and characteristics analysis of acute and chronic aspiration pneumonia].

OBJECTIVE: To discuss about the pathologic and imaging origins and characteristics of CT scaning and X-ray radiography for acute and chronic aspiration pneumonia. METHODS: Imaging data from 30 patients with aspiration pneumonia were retrospectively analyzed, CT scaning was performed in 27 patients, which PMVR reconstruction was performed in 21 cases;3 exammed by X-ray with 2 used by esophagography. RESULTS: Opaque bodies were detected in trachea by CT scaning in 12 patients.7 patients in acute phase rapidly developed into acute respiratory distress syndrome(ARDS). CT signs of 30 patients with acute and chronic aspiration pneumonia included: centrilobular nodules were detected in 2 cases with acute phase, 4 cases with subacute phase and 4 cases with chronic phase; the imaging of ground glass opacity were detected in 9 cases with acute phase, 2 cases with subacute phase and 3 cases with chronic phase; the imaging of bronchiectasis was detected in 8 cases with chronic phase, which mucilage embolism was detected in 3 of 8 cases; the imaging of atelectasis was detected in 6 cases with chronic phase; the imaging of sheeted consolidation was detected in 5 cases with chronic phase, 8 case with acute phase; the imaging of interstitial fibrosis was detected in 3 cases with chronic phase. Lesions of inferior lobe of right lung were detected in 9 cases with chronic phase, 4 cases with subacute phase, 11 case with acute phase;lesions of inferior lobe of left lung were detected in 6 cases with chronic phase and 3 cases with subacute group, 11 case with acute phase. CONCLUSION: The imaging features of acute and chronic aspiration pneumonia overlap with GGO and centrilobular nodules in every group. While the imaging features of atelectasis, bronchiectasis or mucilage embolism are found in chronic phase. The chest CT scaning may accurately evaluate the dynamic change of aspiration pneumonia.

[Diagnostic value of solid component for lung adenocarcinoma shown as ground-glass nodule on computed tomography].

OBJECTIVE: To explore the feasibility of making a preoperative diagnosis of lung adenocarcinoma shown as ground-glass nodule (GGN) on computed tomography (CT). METHODS: A total of 143 GGN lesions proved pathologically were divided randomly into A and B groups. Then each group was further divided pathologically into preinvasive lesion, minimal invasive adenocarcinoma (MIA) and invasive adenocarcinoma (IAC) subgroups. Group A (n = 101), size of lesion, proportion of ground glass opacity (GGO) composition of lesion, long diameter, longest diameter and size of solid component in lesion were measured on CT so as to establish the CT diagnostic standard of lung adenocarcinoma shown as GGN on CT. Group B (n = 42) was employed to evaluate the accuracy of the above CT diagnostic standard. SPSS 17.0 software was used for statistical analysis. RESULTS: Significant statistic significance existed in all parameters among all groups (P < 0.05). All parameters were correlated the pathologic type of lesion. The differences were statistically significant (P = 0.000). Through the receiver operating characteristic (ROC) curve, between groups of preinvasive lesion and MIA, each parameter had a medium diagnostic value of 0.70-0.90; between groups of MIA and IAC, size of lesion and long diameter of solid component in lesion had a medium diagnostic value of 0.70-0.90, longest diameter of solid component, size of solid component in lesion and proportion of GGO composition of lesion had a high diagnostic value with an AUC of >0.90. The CT diagnostic standard, derived from group A, was used to analyze the pathologic type of group B. And t no significant statistic significance existed between CT preoperative diagnosis and operative pathologic diagnosis (P > 0.05) . The correct diagnosis rates of size of lesion, proportion of GGO composition of lesion, long diameter, longest diameter and size of solid component in lesion were 71.43%, 76.19%, 90.05%, 90.05% and 88.10% respectively. CONCLUSION: Based upon size of lesion, proportion of GGO composition of lesion, long diameter, longest diameter and size of solid component in lesion, preoperative CT examination may be used to determine the pathological types of lung adenocarcinoma shown as GGN.

A core/satellite multifunctional nanotheranostic for in vivo imaging and tumor eradication by radiation/photothermal synergistic therapy.

To integrate photothermal ablation (PTA) with radiotherapy (RT) for improved cancer therapy, we constructed a novel multifunctional core/satellite nanotheranostic (CSNT) by decorating ultrasmall CuS nanoparticles onto the surface of a silica-coated rare earth upconversion nanoparticle. These CSNTs could not only convert near-infrared light into heat for effective thermal ablation but also induce a highly localized radiation dose boost to trigger substantially enhanced radiation damage both in vitro and in vivo. With the synergistic interaction between PTA and the enhanced RT, the tumor could be eradicated without visible recurrence in 120 days. Notably, hematological analysis and histological examination unambiguously revealed their negligible toxicity to the mice within a month. Moreover, the novel CSNTs facilitate excellent upconversion luminescence/magnetic resonance/computer tomography trimodal imagings. This multifunctional nanocomposite is believed to be capable of playing a vital role in future oncotherapy by the synergistic effects between enhanced RT and PTA under the potential trimodal imaging guidance.

Multi-detector spiral CT study of the relationships between pulmonary ground-glass nodules and blood vessels.

OBJECTIVE: To investigate the relationships between pulmonary ground-glass nodules (GGN) and blood vessels and their diagnostic values in differentiating GGNs. METHODS: Multi-detector spiral CT imaging of 108 GGNs was retrospectively reviewed. The spatial relationships between GGNs and supplying blood vessels were categorized into four types: I, vessels passing by GGNs; II, intact vessels passing through GGNs; III, distorted, dilated or tortuous vessels seen within GGNs; IV, more complicated vasculature other than described above. Relationship types were correlated to pathologic and/or clinical findings of GGNs. RESULTS: Of 108 GGNs, 10 were benign, 24 preinvasive nodules and 74 adenocarcinomas that were pathologically proven. Types I, II, III and IV vascular relationships were observed in 9, 58, 21 and 20 GGNs, respectively. Type II relationship was the dominating relationship for each GGN group, but significant differences were shown among them. Correlation analysis showed strong correlation between invasive adenocarcinoma and type III and IV relationships. Subgroup analysis indicated that type III was more commonly seen in IAC with comparison to type IV more likely seen in MIA. CONCLUSION: Different GGNs have different relationships with vessels. Understanding and recognising characteristic GGN-vessel relationships may help identify which GGNs are more likely to be malignant.

Improving the image quality in computed tomographic pulmonary angiography with dual-energy subtraction: a new application of spectral computed tomography.

OBJECTIVES: The objectives of this study were to assess quantitative and subjective image quality in computed tomographic pulmonary angiography using dual-energy subtraction methods compared with those of the monochromatic images using optimal contrast-to-noise ratios and those of the routine polychromatic images and to select the best dual-energy subtraction method. MATERIALS AND METHODS: A total of 1 routine polychromatic image, 3 sets of dual-energy subtraction images (DESIs), and 2 sets of monochromatic images with different optimal contrast-to-noise ratios from 30 patients were obtained. The signal intensity and noise were measured; signal-to-noise ratio and contrast-to-noise ratio (CNR) were calculated. The global subjective image quality was subjectively assessed. RESULTS: The DESI 3 got the highest CNR and the DESI 1 got the second highest CNR. The DESI 1 got the highest global subjective image quality score. The 3 subtraction image sets got the highest score in visualization of the pulmonary artery branches. CONCLUSIONS: Computed tomographic pulmonary angiography with dual-energy subtraction technique is feasible. The DESI 1 afforded the best balance between the quantitative analysis and the subjective evaluation.

Assessment of hepatic fatty infiltration using spectral computed tomography imaging: a pilot study.

OBJECTIVE: The objective of this study was to investigate the feasibility of using monochromatic spectral computed tomography (CT) imaging to assess fatty infiltration in liver. MATERIALS: With spectral CT imaging, phantoms with known fat concentrations were studied for scanning parameter optimization, then 52 patients enrolled into 4 groups (healthy, mild, moderate, and severe fatty infiltration) received abdominal scanning. Based on reconstructed monochromatic images, hepatic attenuation was analyzed, and dual-energy subtraction imaging (DESI) was created for quantifying fat infiltration. RESULTS: Corresponding to various hepatic fat infiltrations, 4 characteristic CT attenuation curve patterns were described. In DESI images, only fat and fatty components appeared bright. For livers without abnormal fat deposition, isolated bright pixels were visualized (% area = 0.5% ± 0.3%). With hepatic fat accumulation increasing, more bright pixels appeared in subtraction images with percentages of total liver area involved in 2.5%, 6.7%, and 13.4% of mild, moderate, and severe fat infiltration cases, respectively (P < 0.05). The corresponding CT values were as follows: 1.33, 2.53, 8.69, and 16.4 Hounsfield units (P < 0.01), which correlated with the % DESI area values (r = 0.9811). CONCLUSIONS: Spectral CT imaging is a promising method to quantitatively assess hepatic fat content and fatty infiltration with advantages compared with conventional CT imaging.

Magnetic resonance imaging of the breast in evaluating residual diseases at lumpectomy site soon after excisional biopsy.

OBJECTIVE: To evaluate the role of magnetic resonance imaging (MRI) in the detection of residual disease for patients after excisional biopsy of breast carcinoma, before re-excision. MATERIALS AND METHODS: We performed a retrospective review of 97 patients who underwent MRI soon after excisional biopsy of breast carcinoma with undeterminable margin status before further surgical intervention to determine the value of MRI in detecting residual disease. RESULTS: The positive predictive value was 50.0%. The negative predictive value was 78.9%. The MRI detected 54.5% of the residual disease for invasive ductal carcinoma and 100% for ductal carcinoma in situ. Positive predictive value and sensitivity for MRI conducted within 14 days of the original surgery were lower than those for MRI conducted after 14 days of the original surgery, being 31.6% and 46.2% versus 66.7% and 73.4%, respectively. The difference between the positive predictive value within 14 days versus after 14 days was statistically significant. CONCLUSION: Magnetic resonance imaging in detecting residual disease soon after excisional biopsy for breast carcinoma had a low positive predictive value and moderately high negative predictive value. Magnetic resonance imaging was more sensitive in detecting residual ductal carcinoma in situ than invasive ductal carcinoma. Magnetic resonance imaging conducted more than 14 days after the original biopsy had a significantly higher positive predictive value than MRI done within 14 days.

Automatic segmentation of ground-glass opacities in lung CT images by using Markov random field-based algorithms.

Chest radiologists rely on the segmentation and quantificational analysis of ground-glass opacities (GGO) to perform imaging diagnoses that evaluate the disease severity or recovery stages of diffuse parenchymal lung diseases. However, it is computationally difficult to segment and analyze patterns of GGO while compared with other lung diseases, since GGO usually do not have clear boundaries. In this paper, we present a new approach which automatically segments GGO in lung computed tomography (CT) images using algorithms derived from Markov random field theory. Further, we systematically evaluate the performance of the algorithms in segmenting GGO in lung CT images under different situations. CT image studies from 41 patients with diffuse lung diseases were enrolled in this research. The local distributions were modeled with both simple and adaptive (AMAP) models of maximum a posteriori (MAP). For best segmentation, we used the simulated annealing algorithm with a Gibbs sampler to solve the combinatorial optimization problem of MAP estimators, and we applied a knowledge-guided strategy to reduce false positive regions. We achieved AMAP-based GGO segmentation results of 86.94%, 94.33%, and 94.06% in average sensitivity, specificity, and accuracy, respectively, and we evaluated the performance using radiologists' subjective evaluation and quantificational analysis and diagnosis. We also compared the results of AMAP-based GGO segmentation with those of support vector machine-based methods, and we discuss the reliability and other issues of AMAP-based GGO segmentation. Our research results demonstrate the acceptability and usefulness of AMAP-based GGO segmentation for assisting radiologists in detecting GGO in high-resolution CT diagnostic procedures.

A delta-radiomics model for preoperative prediction of invasive lung adenocarcinomas manifesting as radiological part-solid nodules.

Purpose: This study aims to explore the value of the delta-radiomics (DelRADx) model in predicting the invasiveness of lung adenocarcinoma manifesting as radiological part-solid nodules (PSNs). Methods: A total of 299 PSNs histopathologically confirmed as lung adenocarcinoma (training set, n = 209; validation set, n = 90) in our hospital were retrospectively analyzed from January 2017 to December 2021. All patients underwent diagnostic noncontrast-enhanced CT (NCECT) and contrast-enhanced CT (CECT) before surgery. After image preprocessing and ROI segmentation, 740 radiomic features were extracted from NCECT and CECT, respectively, resulting in 740 DelRADx. A DelRADx model was constructed using the least absolute shrinkage and selection operator logistic (LASSO-logistic) algorithm based on the training cohort. The conventional radiomics model based on NCECT was also constructed following the same process for comparison purposes. The prediction performance was assessed using area under the ROC curve (AUC). To provide an easy-to-use tool, a radiomics-based integrated nomogram was constructed and evaluated by integrated discrimination increment (IDI), calibration curves, decision curve analysis (DCA), and clinical impact plot. Results: The DelRADx signature, which consisted of nine robust selected features, showed significant differences between the AIS/MIA group and IAC group (p < 0.05) in both training and validation sets. The DelRADx signature showed a significantly higher AUC (0.902) compared to the conventional radiomics model based on NCECT (AUC = 0.856) in the validation set. The IDI was significant at 0.0769 for the integrated nomogram compared with the DelRADx signature. The calibration curve of the integrated nomogram demonstrated favorable agreement both in the training set and validation set with a mean absolute error of 0.001 and 0.019, respectively. Decision curve analysis and clinical impact plot indicated that if the threshold probability was within 90%, the integrated nomogram showed a high clinical application value. Conclusion: The DelRADx method has the potential to assist doctors in predicting the invasiveness for patients with PSNs. The integrated nomogram incorporating the DelRADx signature with the radiographic features could facilitate the performance and serve as an alternative way for determining management.

A Computed Tomography-Derived Radiomics Approach for Predicting Uncommon EGFR Mutation in Patients With NSCLC.

PURPOSE: This study aims to develop a CT-based radiomics approach for identifying the uncommon epidermal growth factor receptor (EGFR) mutation in patients with non-small cell lung cancer (NSCLC). METHODS: This study involved 223 NSCLC patients (107 with uncommon EGFR mutation-positive and 116 with uncommon EGFR mutation-negative). A total of 1,269 radiomics features were extracted from the non-contrast-enhanced CT images after image segmentation and preprocessing. Support vector machine algorithm was used for feature selection and model construction. Receiver operating characteristic curve analysis was applied to evaluate the performance of the radiomics signature, the clinicopathological model, and the integrated model. A nomogram was developed and evaluated by using the calibration curve and decision curve analysis. RESULTS: The radiomics signature demonstrated a good performance for predicting the uncommon EGFR mutation in the training cohort (area under the curve, AUC = 0.802; 95% confidence interval, CI: 0.736-0.858) and was verified in the validation cohort (AUC = 0.791, 95% CI: 0.642-0.899). The integrated model combined radiomics signature with clinicopathological independent predictors exhibited an incremental performance compared with the radiomics signature or the clinicopathological model. A nomogram based on the integrated model was developed and showed good calibration (Hosmer-Lemeshow test, P = 0.92 in the training cohort and 0.608 in the validation cohort) and discrimination capacity (AUC of 0.816 in the training cohort and 0.795 in the validation cohort). CONCLUSION: Radiomics signature combined with the clinicopathological features can predict uncommon EGFR mutation in NSCLC patients.

Radiomics signature on CECT as a predictive factor for invasiveness of lung adenocarcinoma manifesting as subcentimeter ground glass nodules.

Controversy and challenges remain regarding the cognition of lung adenocarcinomas presented as subcentimeter ground glass nodules (GGNs). Postoperative lymphatic involvement or intrapulmonary metastasis is found in approximately 15% to 20% of these cases. This study aimed to develop and validate a radiomics signature to identify the invasiveness of lung adenocarcinoma appearing as subcentimeter ground glass nodules. We retrospectively enrolled 318 subcentimeter GGNs with histopathology-confirmed adenocarcinomas in situ (AIS), minimally invasive adenocarcinomas (MIA) and invasive adenocarcinomas (IAC). The radiomics features were extracted from manual segmentation based on contrast-enhanced CT (CECT) and non-contrast enhanced CT (NCECT) images after imaging preprocessing. The Lasso algorithm was applied to construct radiomics signatures. The predictive performance of radiomics models was evaluated by receiver operating characteristic (ROC) analysis. A radiographic-radiomics combined nomogram was developed to evaluate its clinical utility. The radiomics signature on CECT (AUC: 0.896 [95% CI 0.815-0.977]) performed better than the radiomics signature on NCECT data (AUC: 0.851[95% CI 0.712-0.989]) in the validation set. An individualized prediction nomogram was developed using radiomics model on CECT and radiographic model including type, shape and vascular change. The C index of the nomogram was 0.915 in the training set and 0.881 in the validation set, demonstrating good discrimination. Decision curve analysis (DCA) revealed that the proposed model was clinically useful. The radiomics signature built on CECT could provide additional benefit to promote the preoperative prediction of invasiveness in patients with subcentimeter lung adenocarcinomas.