Thin-section Computed Tomography Images Research Articles

Software-based quantitative CT analysis to predict the growth trend of persistent nonsolid pulmonary nodules: a retrospective study

PurposePersistent nonsolid nodules (NSNs) usually exhibit an indolent course and may remain stable for several years; however, some NSNs grow quickly and require surgical excision. Therefore, identifying quantitative features capable of early discrimination between growing and nongrowing NSNs is becoming a crucial aspect of radiological analysis. The main purpose of this study was to evaluate the performance of an open-source software (ImageJ) to predict the future growth of NSNs detected in a Caucasian (Italian) population.Material and methodsWe retrospectively selected 60 NSNs with an axial diameter of 6–30 mm scanned with the same acquisition-reconstruction parameters and the same computed tomography (CT) scanner. Software-based analysis was performed on thin-section CT images using ImageJ. For each NSNs, several quantitative features were extracted from the baseline CT images. The relationships of NSN growth with quantitative CT features and other categorical variables were analyzed using univariate and multivariable logistic regression analyses.ResultsIn multivariable analysis, only the skewness and linear mass density (LMD) were significantly associated with NSN growth, and the skewness was the strongest predictor of growth. In receiver operating characteristic curve analyses, the optimal cutoff values of skewness and LMD were 0.90 and 19.16 mg/mm, respectively. The two predictive models that included the skewness, with or without LMD, exhibited an excellent power for predicting NSN growth.ConclusionAccording to our results, NSNs with a skewness value > 0.90, specifically those with a LMD > 19.16 mg/mm, should require closer follow-up due to their higher growth potential, and higher risk of becoming an active cancer.

MA10.05 Potential of CT and PET-Based Radiomics for the Diagnosis of Lung Adenocarcinomas Indicated for Limited Resection

We previously developed radiomics technology using computed tomography (CT) to identify cases of preinvasive lung adenocarcinoma that may be indicated for limited resection. This study aimed to investigate whether the maximum standardized uptake value (SUVmax) on positron emission tomography (PET) has an add-on effect for this technology. This retrospective observational study was conducted at two medical centers. The resected pulmonary lesions were reviewed between April 2014 and March 2020. Patients with clinical stage IA lung adenocarcinomas were included. Thin-section CT images (less than 2.5 mm) were used to assess the clinical stage. For the image analysis algorithm of plain CT-based radiomics, we previously selected seven parameters: tumor volume (cm3), volume rate of the solid component (%solid; %), mean CT value (Hounsfield units), kurtosis, skewness, variance, and entropy. In this study, a new prediction model based on multiple logistic regression comprising eight parameters (CT＋PET-based radiomics) was generated, including SUVmax, after standardization to eliminate inter-facility bias. Next, stepwise variable selection was applied to the prediction model to evaluate whether SUVmax was a more important factor for identifying pathological preinvasive adenocarcinomas. A bootstrap method for randomized selection was used to assess the accuracy of the results. A total of 262 lung adenocarcinomas were categorized into the invasive group (n = 166 [63%]) or a preinvasive group (n = 96 [37%]), the latter of which comprised adenocarcinomas in situ (n = 32 [33%]) and minimally invasive adenocarcinomas (n = 64 [67%]). Before the surgery, the mean total tumor size of the invasive group (17.0 ± 6.5 mm) was significantly greater than that of the preinvasive group (13.9 ± 5.6 mm; p < 0.001). The pathological T factors were Tis (n = 32), T1mi (n = 64), T1a (n = 83), T1b (n = 66), and T1c (n = 17). Although spread through air spaces (STAS) was observed in 24 specimens (9.2%), five STAS-positive cases (5.2%) were noted in the preinvasive group. Upstaging was confirmed in one patient with lymph node-positive metastasis (N1) after pathological diagnosis. However, there were no cases of upstaging among the preinvasive tumors. Before standardization, the median SUVmax was 0.6 (interquartile range [IQR], 0.00–1.40) in the preinvasive group and 1.7 [IQR, 0.99–2.85]) in the invasive group (p < 0.001). After a stepwise method involving the eight factors, %solid (odds ratio [OR], 0.30; 95% confidence interval [CI], 0.20–0.46; p < 0.001) and entropy (OR, 0.46; 95% CI, 0.32–0.67; p < 0.001) were selected, but not SUVmax. The area under the curve was 0.83 (95% CI, 0.78–0.88). In the bootstrapping analysis, SUVmax was never selected as a key factor compared with the original parameters of CT-based radiomics. Even when the five STAS-positive cases in the preinvasive group were reclassified into the invasive group, SUVmax did not remain a key factor in the discrimination. In the identification of cases of preinvasive adenocarcinomas for which limited resection may be indicated, SUVmax did not increase the diagnostic efficacy of the original CT-based radiomics.

Clinical significance of part-solid lung cancer in the eighth edition TNM staging system.

The ground-glass component of part-solid tumour (PST) was eliminated as a clinical T (cT) descriptor in the eighth edition of the tumour, node and metastasis (TNM) staging system. We aimed to validate the new cT descriptor and investigate the prognostic impact of PST in the new staging system. Non-small-cell lung cancer (NSCLC) patients (n = 1061) who underwent lung resection and were available for the assessment of thin-section computed tomography images were retrospectively reviewed. Tumours with a solid component (SC) size-to-whole tumour size (STR) ratio of 0, those with 0 < STR < 1 and those with an STR of 1 were defined as pure ground-glass tumours, PSTs and solid tumours (STs), respectively. Tumours with an SC diameter of >30 mm were less frequently observed among PSTs than among STs (4.83% vs 32.6%, P < 0.001). The postoperative 5-year survival of NSCLC patients with ground-glass tumour, PST and ST was 97.6%, 89.0% and 76.3%, respectively. In the survival analysis of patients with an SC diameter ≤30 mm, significant differences were observed among PST and ST (5-year survival, 90.7% vs 74.6%, P < 0.001). The multivariable analysis showed that age <70 years old, female sex, procedures with a lobectomy or more, SC size, pN0 disease and PST were independent predictors of a better survival among all PST and ST patients. Among patients with cT1 tumours, those with PST showed a significantly better survival than did those with ST. Small-sized PST tumours may not be suitable for the new cT descriptor.

Analysis of CT morphologic features and attenuation for differentiating among transient lesions, atypical adenomatous hyperplasia, adenocarcinoma in situ, minimally invasive and invasive adenocarcinoma presenting as pure ground-glass nodules

Thin-section computed tomography (TSCT) imaging biomarkers are uncertain to distinguish progressive adenocarcinoma from benign lesions in pGGNs. The purpose of this study was to evaluate the usefulness of TSCT characteristics for differentiating among transient (TRA) lesions, atypical adenomatous hyperplasia (AAH), adenocarcinoma in situ (AIS), minimally invasive adenocarcinoma (MIA) and invasive adenocarcinoma (IAC) presenting as pure ground-glass nodules (pGGNs). Between January 2016 and January 2018, 255 pGGNs, including 64 TRA, 22 AAH, 37 AIS, 108 MIA and 24 IAC cases, were reviewed on TSCT images. Differences in TSCT characteristics were compared among these five subtypes of pGGNs. Logistic analysis was performed to identify significant factors for predicting MIA and IAC. Progressive pGGNs were more likely to be round or oval in shape, with clear margins, air bronchograms, vascular and pleural changes, creep growth, and bubble-like lucency than were non-progressive pGGNs. The optimal cut-off values of the maximum diameter for differentiating non-progressive from progressive pGGNs and IAC from non-IAC were 6.5 mm and 11.5 mm, respectively. For the prediction of IAC vs. non-IAC and non-progressive vs. progressive adenocarcinoma, the areas under the receiver operating characteristics curves were 0.865 and 0.783 for maximum diameter and 0.784 and 0.722 for maximum CT attenuation, respectively. The optimal cut-off values of maximum CT attenuation were −532 HU and −574 HU for differentiating non-progressive from progressive pGGNs and IAC from non-IAC, respectively. Maximum diameter, maximum attenuation and morphological characteristics could help distinguish TRA lesions from MIA and IAC but not from AAH. So, CT morphologic characteristics, diameter and attenuation parameters are useful for differentiating among pGGNs of different subtypes.

Quantitative Measurement of the Three-dimensional Structure of the Vocal Folds and Its Application in Identifying the Type of Cricoarytenoid Joint Dislocation

The objective of this study was to quantitatively measure the three-dimensional (3D) structure of the vocal folds in normal subjects and in patients with different types of cricoarytenoid dislocation. We will analyze differences in parameters between the groups and also determine if any morphologic parameters possess utility in distinguishing the type and the degree of cricoarytenoid dislocation. This retrospective study was conducted using university hospital data. Subjects' larynges were scanned using dual-source computed tomography (CT). The normal subjects were divided into deep-inhalation and phonation groups, and patients with cricoarytenoid joint dislocation were divided into anterior-dislocation and posterior-dislocation groups. Membranous vocal fold length and width were measured directly on the thin-section CT images. Vocal fold and airway 3D models were constructed using Mimics software and used in combination to measure vocal fold thickness, subglottal convergence angle, and oblique angle of the vocal folds. The phonation group displayed a greater vocal fold width, greater oblique angle, thinner vocal folds, and a smaller subglottal convergence angle than those of the deep-inhalation group (P < 0.05). The anterior-dislocation group displayed a smaller oblique angle and subglottal convergence angle than the posterior-dislocation group (P < 0.05). The 3D structure of the vocal folds during deep inhalation and phonation can be accurately measured using dual-source CT and laryngeal 3D reconstruction. As the anterior-dislocation group yielded negative values for the oblique angle and the posterior-dislocation group yielded positive values, the oblique angle of the vocal folds may possess utility for distinguishing the type and for quantitatively determining the degree of cricoarytenoid dislocation.

The Protective Effect of Middle Cerebral Artery Calcification on Symptomatic Middle Cerebral Artery Infarction.

The presence of intracranial artery calcification is associated with an increased risk for stroke. However, calcified atherosclerotic plaques are also known to be less vulnerable to rupture. Given this discrepancy, we investigated whether the vulnerability of intracranial arterial atherosclerosis differed based on the presence or absence of calcification. We considered consecutive patients with acute stroke in the unilateral middle cerebral artery (MCA) territory. Patients with any stenotic MCAs were included in this study. Symptomatic MCA was defined as the occurrence of infarctions relevant to the stenotic MCA. The presence of calcification in the MCA was evaluated on noncontrast thin-section computed tomography images using a 3dimensional software package. Generalized estimating equations were used to compare the frequency of calcification between symptomatic and asymptomatic stenosis. Of the 1066 MCAs examined in 533 patients, 645 MCAs were stenotic and were included in the study. Among the 645 stenotic MCAs, 406 MCAs (62.9%) were symptomatic. Calcification was observed in 36 MCAs (5.6%). Calcification in the MCA was more frequently observed in the asymptomatic group (7.9% versus 4.2%; P=0.032). On multivariable analysis, the presence of calcification in MCA atherosclerosis was less frequent in the symptomatic group (odds ratio, 0.46; 95% confidence interval, 0.23-0.92; P=0.027). This study showed that calcified atherosclerosis in the MCA was less frequently symptomatic.

Clinical Significance of Incidentally Detected Torus Tubarius Calcification.

Calcification of the torus tubarius has been rarely reported in the literature. Histopathologic studies have previously described cases of Eustachian tube calcification and cite an association with increasing patient age. The purpose of this study was to examine the prevalence of torus tubarius calcification and potential clinical significance on an unrestricted patient population using thin-section computed tomography (CT), which has not been previously reported. After the institutional review board approval, 1571 consecutive patients who underwent noncontrast head CT between January 2011 and July 2011 were retrospectively reviewed for torus tubarius calcification. Images were acquired at 1.25-mm slice thickness using a 64-detector row CT. Medical records were reviewed for chronic medical conditions including chronic kidney disease, alcoholism, autoimmune conditions, endocrine disorders, elevated alkaline phosphatase levels, history of otitis media, purified protein derivative positivity, history of head and neck surgery and radiation, and human immunodeficiency virus infection. Motion-limited studies and patients with limited clinical data were excluded. Statistical analyses were performed using the independent sample t test and Fisher exact test. Ten (0.6%) of 1571 patients had torus tubarius calcification, of which 7 (70%) were unilateral, and 3 (30%) were bilateral calcification. There was no significant association between torus tubarius calcification and common medical disorders including endocrine disorders, human immunodeficiency virus, chronic kidney disease, alcoholism, purified protein derivative positivity, history of head and neck surgery or radiation, and autoimmune diseases. Based on the largest series to date on an unrestricted population using thin-section CT imaging, calcification of the torus tubarius is a rare entity with an overall prevalence of 0.6%. Although the clinical significance remains uncertain, there is no significant association between torus tubarius calcification and common medical conditions.

SS31 Effects of Different Stent Designs on Limb Flexion-Induced Axial Compression, Bending, and Torsion in Human Femoropopliteal Arteries

Endovascular reconstructions of the femoropopliteal artery (FPA) demonstrate high rates of failure. Poor durability of repair is often attributed to severe mechanical deformations that occur with limb flexion and inability of stent designs to accommodate these deformations. Stent-artery interactions associated with limb flexion-induced FPA deformations may contribute to arterial wall injury and intimal hyperplasia. We measured limb flexion-induced deformations of human cadaveric FPAs before and after stenting with seven different commercially available peripheral artery stents. Retrievable nitinol markers were deployed into 28 in situ FPAs of 14 human cadavers. Limbs were perfused with 37°C fluid, and thin-section computed tomography images were acquired with limbs in the standing (180°), walking (110°), sitting (90°) and gardening (60°) postures. Image segmentation and analysis allowed comparison of relative spatial locations of each intra-arterial marker for determination of baseline FPA axial compression, bending, and torsion. Markers were then retrieved from the arteries, and the FPAs were stented with pre- and post-balloon dilatation. Zilver, Absolute Pro, Innova, Smart Control, SmartFlex, Supera stents, and Viabahn stent grafts were deployed across the adductor hiatus. Four unique limbs received each stent type with only one stent type per artery. After stenting, markers were redeployed in stented FPAs and imaged in the same postures. Comparison of the baseline and stented FPA deformations allowed determination of the influence of specific stent type (Fig). Smart Control, Smart Flex, Zilver, Supera, and Absolute Pro restricted axial compression of the FPA within the stented segment by 56%, 45%, 42%, 26%, and 22%, respectively (P < .05). Smart Flex, Smart Control, and Zilver exacerbated FPA compression distal to the stent by 61% (P < .01), while no differences were observed proximally. Within the stented segment, maximum torsion was restricted by Supera 4° to 12°/cm (P < .05), and exacerbated by Smart Flex 10° to 15°/cm (P < .05). Torsion of the FPA proximal and distal to the stented region was not affected by stenting. Stents reduced bending of the FPA by an average of 42% (P < .01) within the stented segment, but no differences were observed proximally or distally. Different stent designs significantly affect limb flexion-induced deformations of the FPA not only within the stented segment but also distal to it. Stents that better match natural limb flexion-induced FPA deformations may mitigate arterial injury and potentially improve clinical outcomes of endovascular peripheral artery disease treatments. These data can be used to help more rationally select stent designs specific to arterial segments and patient conditions.

Limb flexion-induced axial compression and bending in human femoropopliteal artery segments

BackgroundHigh failure rates of femoropopliteal artery (FPA) interventions are often attributed in part to severe mechanical deformations that occur with limb movement. Axial compression and bending of the FPA likely play significant roles in FPA disease development and reconstruction failure, but these deformations are poorly characterized. The goal of this study was to quantify axial compression and bending of human FPAs that are placed in positions commonly assumed during the normal course of daily activities. MethodsRetrievable nitinol markers were deployed using a custom-made catheter system into 28 in situ FPAs of 14 human cadavers. Contrast-enhanced, thin-section computed tomography images were acquired with each limb in the standing (180 degrees), walking (110 degrees), sitting (90 degrees), and gardening (60 degrees) postures. Image segmentation and analysis allowed relative comparison of spatial locations of each intra-arterial marker to determine axial compression and bending using the arterial centerlines. ResultsAxial compression in the popliteal artery (PA) was greater than in the proximal superficial femoral artery (SFA) or the adductor hiatus (AH) segments in all postures (P = .02). Average compression in the SFA, AH, and PA ranged from 9% to 15%, 11% to 19%, and 13% to 25%, respectively. The FPA experienced significantly more acute bending in the AH and PA segments compared with the proximal SFA (P < .05) in all postures. In the walking, sitting, and gardening postures, average sphere radii in the SFA, AH, and PA ranged from 21 to 27 mm, 10 to 18 mm, and 8 to 19 mm, whereas bending angles ranged from 150 to 157 degrees, 136 to 147 degrees, and 137 to 148 degrees, respectively. ConclusionsThe FPA experiences significant axial compression and bending during limb flexion that occur at even modest limb angles. Moreover, different segments of the FPA appear to undergo significantly different degrees of deformation. Understanding the effects of limb flexion on axial compression and bending might assist with reconstructive device selection for patients requiring peripheral arterial disease intervention and may also help guide the development of devices with improved characteristics that can better adapt to the dynamic environment of the lower extremity vasculature.

Thin-section computed tomography–histopathologic comparisons of pulmonary focal interstitial fibrosis, atypical adenomatous hyperplasia, adenocarcinoma in situ, and minimally invasive adenocarcinoma with pure ground-glass opacity

ObjectiveTo retrospectively compare focal interstitial fibrosis (FIF), atypical adenomatous hyperplasia (AAH), adenocarcinoma in situ (AIS), and minimally invasive adenocarcinoma (MIA) with pure ground-glass opacity (GGO) using thin-section computed tomography (CT). Materials and methodsSixty pathologically confirmed cases were reviewed including 7 cases of FIF, 17 of AAH, 23of AIS, and 13 of MIA. All nodules kept pure ground glass appearances before surgical resection and their last time of thin-section CT imaging data before operation were collected. Differences of patient demographics and CT features were compared among these four types of lesions. ResultsFIF occurred more frequently in males and smokers while the others occurred more frequently in female nonsmokers. Nodule size was significant larger in MIA (P<0.001, cut-off value=7.5mm). Nodule shape (P=0.045), margin characteristics (P<0.001), the presence of pleural indentation (P=0.032), and vascular ingress (P<0.001) were significant factors that differentiated the 4 groups. A concave margin was only demonstrated in a high proportion of FIF at 85.7% (P=0.002). There were no significant differences (all P>0.05) in age, malignant history, attenuation value, location, and presence of bubble-like lucency. ConclusionA nodule size >7.5mm increases the possibility of MIA. A concave margin could be useful for differentiation of FIF from the other malignant or pre-malignant GGO nodules. The presence of spiculation or pleural indentation may preclude the diagnosis of AAH.

Visualization of Middle Ear Ossicles in Elder Subjects with Ultra-short Echo Time MR Imaging.

Purpose:To evaluate the visualization of middle ear ossicles by ultra-short echo time magnetic resonance (MR) imaging at 3T in subjects over 50 years old.Materials and Methods:Sixty ears from 30 elder patients that underwent surgical or interventional treatment for neurovascular diseases were included (ages: 50–82, median age: 65; 10 men, 20 women). Patients received follow-up MR imaging including routine T1- and T2-weighted images, time-of-flight MR angiography, and ultra-short echo time imaging (PETRA, pointwise encoding time reduction with radial acquisition). All patients underwent computed tomography (CT) angiography before treatment. Thin-section source CT images were correlated with PETRA images. Scan parameters for PETRA were: TR 3.13, TE 0.07, flip angle 6 degrees, 0.83 × 0.83 × 0.83 mm resolution, 3 min 43 s scan time. Two radiologists retrospectively evaluated the visibility of each ossicular structure as positive or negative using PETRA images. The structures evaluated included the head of the malleus, manubrium of the malleus, body of the incus, long process of the incus, and the stapes. Signal intensity of the ossicles was classified as: between labyrinthine fluid and air, similar to labyrinthine fluid, between labyrinthine fluid and cerebellar parenchyma, or higher than cerebellar parenchyma.Results:In all ears, the body of the incus was visible. The head of the malleus was visualized in 36/60 ears. The manubrium of the malleus and long process of the incus was visualized in 1/60 and 4/60 ears, respectively. The stapes were not visualized in any ear. Signal intensity of the visible structures was between labyrinthine fluid and air in all ears.Conclusion:The body of the incus was consistently visualized with intensity between air and labyrinthine fluid on PETRA images in aged subjects. Poor visualization of the manubrium of the malleus, long process of the incus, and the stapes limits clinical significance of middle ear imaging with current PETRA methods.

Evaluation of Semi-automatic Segmentation Methods for Persistent Ground Glass Nodules on Thin-Section CT Scans.

ObjectivesThis work was a comparative study that aimed to find a proper method for accurately segmenting persistent ground glass nodules (GGN) in thin-section computed tomography (CT) images after detecting them.MethodsTo do this, we first applied five types of semi-automatic segmentation methods (i.e., level-set-based active contour model, localized region-based active contour model, seeded region growing, K-means clustering, and fuzzy C-means clustering) to preprocessed GGN images, respectively. Then, to measure the similarities, we calculated the Dice coefficient of the segmented area using each semiautomatic method with the result of the manually segmented area by two radiologists.ResultsComparison experiments were performed using 40 persistent GGNs. In our experiment, the mean Dice coefficient for each semiautomatic segmentation tool with manually segmented area was 0.808 for the level-set-based active contour model, 0.8001 for the localized region-based active contour model, 0.629 for seeded region growing, 0.7953 for K-means clustering, and 0.7999 for fuzzy C-means clustering, respectively.ConclusionsThe level-set-based active contour model algorithm showed the best performance, which was most similar to the result of manual segmentation by two radiologists. From the differentiation between the normal parenchyma and the nodule, it was also the most efficient. Effective segmentation methods will be essential for the development of computer-aided diagnosis systems for more accurate early diagnosis and prognosis of lung cancer in thin-section CT images.

Combining of Local Histogram and Local Slice Feature Vectors for Classifying Diffuse Lung Opacities in Thin-Section Computed Tomography Images

Combining of Local Histogram and Local Slice Feature Vectors for Classifying Diffuse Lung Opacities in Thin-Section Computed Tomography Images

The oncological outcomes of segmentectomy in clinical-T1b lung adenocarcinoma with a solid-dominant appearance on thin-section computed tomography.

We investigated the surgical outcomes of clinical-T1b lung adenocarcinomas patients whose tumors had a solid-dominant radiological appearance and who were treated with segmentectomy or lobectomy. We examined 154 surgically resected clinical-T1b lung adenocarcinomas with a "solid-dominant" appearance on thin-section computed tomography (CT). The preoperative thin-section CT images of all cases were reviewed. "Solid-dominant" was defined as 0.5≤ consolidation/tumor ratio (CTR) <1.0. Pathological nodal metastasis, lymphatic invasion, vascular invasion, and pleural invasion were found in 7 (4.5%), 27 (18%), 21 (14%), and 15 (10%) patients with clinical-T1b solid-dominant lung adenocarcinoma, respectively. Lobectomy and segmentectomy were performed in 123 (80%) and 31 (20%) cases, respectively. The 3-year overall survival (OS) and relapse-free survival (RFS) of patients with clinical-T1b solid-dominant lung adenocarcinoma were 95.5 and 92.4%, respectively. The 3-year RFS and OS did not differ significantly between the patients who underwent lobectomy or segmentectomy (3-year RFS, 92.3 vs. 93.4%, p=0.8713; 3-year OS, 95.3 vs. 96.6%, p=0.7603). Segmentectomy was not found to be a prognostic factor for RFS (p=0.8714), or OS (p=0.7613). Segmentectomy can achieve acceptable oncological outcomes (both in terms of OS and RFS), which are similar to those achieved with standard lobectomy, in patients with clinical-T1b solid-dominant lung adenocarcinoma.

Diagnostic certainty of idiopathic pulmonary fibrosis/usual interstitial pneumonia: The effect of the integrated clinico-radiological assessment

ObjectiveTo reevaluate idiopathic pulmonary fibrosis (IPF) cases which had surgical lung biopsy (SLB) for diagnosis of usual interstitial pneumonia (UIP), and examine the influence of computed tomography (CT) findings and clinical information based on diagnostic certainty. MethodsNinety-five cases with multidisciplinary diagnoses of IPF were identified from eight institutions. All cases had SLB. Two expert chest radiologists and five expert pulmonologists used a 5-point scale to grade their level of certainty in the diagnosis of a radiological pattern of UIP or a clinical diagnosis of IPF (level 1 “definitely no” to level 5 “definitely yes”). Radiologists independently evaluated thin-section CT images and pulmonologists independently assessed clinical information. The two groups then discussed their diagnosis to obtain a final consensus, and listed alternative diagnoses. Changes in the level of certainty during the diagnostic process were investigated. ResultsThe level of certainty for IPF was judged as low (level 1 or 2) in 32 cases (34%) by radiologists and in three cases (3%) by pulmonologists; in the final consensus 39 cases (41%) were judged as low. Chronic hypersensitivity pneumonitis (CHP), interstitial pneumonia associated with collagen tissue diseases (CTD-IP), and idiopathic nonspecific interstitial pneumonia (idiopathic NSIP) were listed as alternative diagnoses. ConclusionsIn this retrospective series, some cases that had UIP confirmed on SLB for IPF diagnosis were classified into a low-level certainty group by expert chest radiologists and pulmonologists. When a diagnosis of IPF is made, the possibility of CHP, CTD-IP, and idiopathic NSIP must be also considered.

Simulated lesion, human observer performance comparison between thin-section dedicated breast CT images versus computed thick-section simulated projection images of the breast

The objective of this study was to compare the lesion detection performance of human observers between thin-section computed tomography images of the breast, with thick-section (>40 mm) simulated projection images of the breast.Three radiologists and six physicists each executed a two alterative force choice (2AFC) study involving simulated spherical lesions placed mathematically into breast images produced on a prototype dedicated breast CT scanner. The breast image data sets from 88 patients were used to create 352 pairs of image data. Spherical lesions with diameters of 1, 2, 3, 5, and 11 mm were simulated and adaptively positioned into 3D breast CT image data sets; the native thin section (0.33 mm) images were averaged to produce images with different slice thicknesses; average section thicknesses of 0.33, 0.71, 1.5 and 2.9 mm were representative of breast CT; the average 43 mm slice thickness served to simulate simulated projection images of the breast.The percent correct of the human observer’s responses were evaluated in the 2AFC experiments. Radiologists lesion detection performance was significantly (p < 0.05) better in the case of thin-section images, compared to thick section images similar to mammography, for all but the 1 mm lesion diameter lesions. For example, the average of three radiologist’s performance for 3 mm diameter lesions was 92% correct for thin section breast CT images while it was 67% for the simulated projection images. A gradual reduction in observer performance was observed as the section thickness increased beyond about 1 mm. While a performance difference based on breast density was seen in both breast CT and the projection image results, the average radiologist performance using breast CT images in dense breasts outperformed the performance using simulated projection images in fatty breasts for all lesion diameters except 11 mm. The average radiologist performance outperformed that of the average physicist observer, however trends in performance were similar.Human observers demonstrate significantly better mass-lesion detection performance on thin-section CT images of the breast, compared to thick-section simulated projection images of the breast.

Prognostic evaluations of small size lung cancers by 18F-FDG PET/CT and thin-section CT

PurposePrimary lung cancers have varying prognoses, even for tumors ≤3cm in diameter. Thus, a thorough evaluation is necessary for therapeutic planning. Two imaging biomarkers have been shown to be useful for predicting primary lung cancer prognosis: maximum standardized uptake values (SUVmax) on fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) and the consolidation/tumor (C/T) ratio defined as the maximum diameter of consolidation within a tumor to the maximum tumor diameter on thin-section computed tomography (TSCT). We compared these biomarkers for predicting post-surgical recurrence in patients with small lung cancers. Materials and methodsClinical records, post-operative pathologic findings, and pre-operative PET/CT and TSCT images were reviewed. Solitary primary lung cancers of ≤3cm in diameter after surgical resection were selected for analysis. SUVmax and C/T ratios were recorded. Kaplan–Meier survival curves and Cox hazards ratios were used to identify independent predictors of lung cancer recurrence from among age, gender, surgical procedure, lesion size, C/T ratio, and SUVmax. ResultsA total of 169 patients (114 males and 55 females; age range: 34–87 years) with solitary lung cancers were evaluated. The median post-operative follow-up period was 42 months. Twenty-eight patients had cancer recurrence with significantly higher SUVmax (p<0.001) and C/T ratios (p<0.001) than patients without recurrence. Disease-free survival was significantly reduced for SUVmax of ≥2.5 vs. SUVmax of <2.5 (p<0.001) or for a C/T ratio of ≥50% vs. a C/T ratio of <50% (p=0.030). For 19 patients with C/T ratios of <50%, none had a post-operative recurrence. A Cox hazards ratio model showed that only SUVmax was an independent predictor of recurrence (hazards ratio=1.324; p<0.001). ConclusionSUVmax on FDG-PET/CT was a significant imaging biomarker relevant to the prognosis of patients with lung cancers, and was superior to the C/T ratio on TSCT for predicting postoperative recurrence, particularly for solid type lung cancer.

Temporal Subtraction Method for Lung Nodule Detection on Successive Thoracic CT Soft-Copy Images

To assess the effects of a new computed tomographic (CT) temporal subtraction (TS) method on radiologist performance in lung nodule detection on thin-section CT images. The institutional review board approved this study, and the informed consent requirement was waived. Fifty pairs (current and previous CT images) of standard-dose 2-mm thin-section CT images and corresponding CT TS images were used for an observer performance study. Two thoracic radiologists identified 30 nodules ranging in size from 5 to 19 mm, and these nodules served as the reference standard of actionable nodules (noncalcified nodules larger than 4 mm). Eight radiologists (four attending radiologists, four radiology residents) participated in this observer study. Ratings and locations of lesions determined by observers were used to assess the significance of differences between radiologists' performances without and with the CT TS images in jacknife free-response receiver operating characteristics analysis. Average figure of merit values increased significantly for all radiologists (from 0.838 without CT TS images to 0.894 with CT TS images [P = .033]). Average sensitivity for detection of actionable nodules was improved from 73.4% to 83.4%, with a false-positive rate of 0.15 per case, by using CT TS images. The reading time with CT TS images was not significantly different from that without. The novel CT TS method would increase observer performance for lung nodule detection without considerably extending the reading time.

Measurement of Focal Ground-glass Opacity Diameters on CT Images: Interobserver Agreement in Regard to Identifying Increases in the Size of Ground-Glass Opacities

To evaluate interobserver agreement in regard to measurements of focal ground-glass opacities (GGO) diameters on computed tomography (CT) images to identify increases in the size of GGOs. Approval by the institutional review board and informed consent by the patients were obtained. Ten GGOs (mean size, 10.4 mm; range, 6.5-15 mm), one each in 10 patients (mean age, 65.9 years; range, 58-78 years), were used to make the diameter measurements. Eleven radiologists independently measured the diameters of the GGOs on a total of 40 thin-section CT images (the first [n = 10], the second [n = 10], and the third [n = 10] follow-up CT examinations and remeasurement of the first [n = 10] follow-up CT examinations) without comparing time-lapse CT images. Interobserver agreement was assessed by means of Bland-Altman plots. The smallest range of the 95% limits of interobserver agreement between the members of the 55 pairs of the 11 radiologists in regard to maximal diameter was -1.14 to 1.72 mm, and the largest range was -7.7 to 1.7 mm. The mean value of the lower limit of the 95% limits of agreement was -3.1 ± 1.4 mm, and the mean value of their upper limit was 2.5 ± 1.1 mm. When measurements are made by any two radiologists, an increase in the length of the maximal diameter of more than 1.72 mm would be necessary in order to be able to state that the maximal diameter of a particular GGO had actually increased.

An animal experiment about early pulmonary candidiasis in immunosuppressive rabbits: thin-section CT images dynamically observed and proved by histopathological results

Early detection and treatment of pulmonary fungal infection in immunocompromised patients has a profound impact on mortality. However, information available about the thin-section computed tomography (CT) findings of Candida pneumonia has largely been limited to isolated cases seen in reviews of various infections and to other acute lung diseases seen in immunocompromised patients. To dynamically observe and evaluate CT findings in immunosuppressed animals with histopathologically confirmed pulmonary candidiasis at the acute stage. Twenty-four New Zealand rabbits were randomly divided into an experimental group (n = 21) and a control group (n = 3). Pulmonary candidiasis was established by C. albicans inoculation via a transtracheal route in immunosuppressed rabbits in the experimental group, and an equivalent amount of normal saline was injected via the same way in the control group. Chest CT scan was performed before and on alternative days after inoculation/injection. Microbiological and pathological results were obtained by autopsy. In the experiment group, pulmonary candidiasis was successfully established in 13 rabbits as confirmed by microbiology and pathology. Areas of air-space consolidation were present in 10 (10/13) rabbits, with lobular distribution in six and lobar or segmental distribution in four, pathologically presenting as bronchopneumonia or hemorrhagic lung infarcts. Areas of ground-glass opacity (GGO) were identified in five (5/13) rabbits, three of which were associated with other abnormalities, presenting as bronchopneumonia or interstitial pneumonitis. Multiple nodules were seen in three (3/13) rabbits. They were clustered around bronchovascular bundles in two rabbits, and subpleural in the remaining one, pathologically presenting as hemorrhagic granulomas. Other less common CT findings included thickening of bronchovascular bundles (n = 3), linear opacity (n = 1), and pneumothorax (n = 1). No abnormality was detected by CT scan and pathological examination in the three rabbits of the control group. Peripheral multiple areas of lobular consolidation and/or GGO representing bronchopneumonia were the most common thin-section CT findings of pulmonary candidiasis at the early stage.