Application of Texture and Volume Model Analysis to Dedicated Axillary High-resolution 3D T2-weighted MR Imaging: A Novel Method for Diagnosing Lymph Node Metastasis in Patients with Clinically Node-negative Breast Cancer.

PURPOSE: To evaluate the effectiveness of the texture analysis of axillary high-resolution 3D T2-weighted imaging (T2WI) in distinguishing positive and negative lymph node (LN) metastasis in patients with clinically node-negative breast cancer. METHODS: Between December 2017 and May 2021, 242 consecutive patients underwent high-resolution 3D T2WI and were classified into the training (n = 160) and validation cohorts (n = 82). We performed manual 3D segmentation of all visible LNs in axillary level I to extract the texture features. As the additional parameters, the number of the LNs and the total volume of all LNs for each case were calculated. The least absolute shrinkage and selection operator algorithm and Random Forest were used to construct the models. We constructed the texture model using the features from the LN with the largest least axis length in the training cohort. Furthermore, we constructed the 3 models combining the selected texture features of the LN with the largest least axis length, the number of LNs, and the total volume of all LNs: texture-number model, texture-volume model, and texture-number-volume model. As a conventional method, we manually measured the largest cortical diameter. Moreover, we performed the receiver operating curve analysis in the validation cohort and compared area under the curves (AUCs) of the models. RESULTS: The AUCs of the texture model, texture-number model, texture-volume model, texture-number-volume model, and conventional method in the validation cohort were 0.7677, 0.7403, 0.8129, 0.7448, and 0.6851, respectively. The AUC of the texture-volume model was higher than those of other models and conventional method. The sensitivity, specificity, positive predictive value, and negative predictive value of the texture-volume model were 90%, 69%, 49%, and 96%, respectively. CONCLUSION: The texture-volume model of high-resolution 3D T2WI effectively distinguished positive and negative LN metastasis for patients with clinically node-negative breast cancer.

A New Magnetic Resonance Imaging Method for 2 Tissue Suppression: Double Tissue Suppression With Multiecho Acquisition and Single Inversion Time Combining High-Intensity Reduction (DOMUST-HIRE).

INTRODUCTION: The fluid-attenuated inversion recovery (FLAIR) method is one of the most important magnetic resonance imaging techniques for the brain, and the high-intensity reduction (HIRE) method is an imaging technique to obtain cerebrospinal fluid suppression images by subtracting long echo time images from short echo time images. In contrast, the double inversion recovery technique suppresses 2 types of tissue signals with different T1 values by applying 2 inversion recovery pulses with different inversion times. However, the double inversion recovery method requires the setting of 2 inversion times in a sequence; thus, its use is limited to relatively high-specification equipment. Here, we propose a new sequence called double tissue suppression with multiecho acquisition and single inversion time combining high-intensity reduction (DOMUST-HIRE) that suppresses the 2 tissues by adding single inversion recovery pulses to a sequence based on the HIRE method. METHODS: In this small clinical study, we performed physical evaluation by imaging a subject's head with FLAIR and DOMUST-HIRE method. RESULTS: The DOMUST-HIRE method can increase the contrast ratio and the contrast-to-noise ratio between white matter (WM) and gray matter, whereas the signal-to-noise ratio between WM and gray matter decreased than with FLAIR method. CONCLUSIONS: The DOMUST-HIRE method can be used to suppress WM and cerebrospinal fluid signals.

Turbo Spin-echo Diffusion-weighted Imaging Compared with Single-shot Echo-planar Diffusion-weighted Imaging: Image Quality and Diagnostic Performance When Differentiating between Ductal Carcinoma in situ and Invasive Ductal Carcinoma.

PURPOSE: To compare the image quality between turbo spin-echo (TSE)-diffusion weighted imaging (DWI) and single-shot echo-planar imaging (EPI)-DWI, and to verify the diagnostic performance of the apparent diffusion coefficient (ADC) parameters of the two techniques by using histogram analysis in terms of differentiation between ductal carcinoma in situ (DCIS) and invasive ductal carcinoma (IDC) lesions. METHODS: Ninety-four women with 94 lesions diagnosed as breast cancer by surgery underwent IRB-approved preoperative magnetic resonance imaging, including TSE and EPI-DWI with b-values of 50 and 850 s/mm2. Twenty lesions were identified as DCIS and 74 as IDC. Image quality [signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and geometric distortion] was evaluated quantitatively and compared between the TSE and EPI-DWI. A histogram analysis of the entire tumor voxel-based ADC data was performed, and the 10th, 25th, 50th, 75th, and 90th percentile values of each technique were compared between DCIS and IDC lesions. RESULTS: The SNR and CNR of TSE-DWI were significantly higher than those of EPI-DWI (P < 0.0001 and < 0.0001). The geometric distortion of TSE-DWI was significantly lower than that of EPI-DWI (P < 0.0001). In TSE-DWI, the 10th, 25th, 50th, and 75th percentile values were significantly different between the DCIS and IDC lesions (P = 0.0010, 0.0004, 0.0008, and 0.0044, respectively). In EPI-DWI, the 50th and 75th percentile values were significantly different between the two groups (P = 0.0009 and 0.0093). There was no significant difference in the area under the curve of the receiver operating characteristic analysis of the 10th, 25th, 50th, and 75th percentile values of TSE-DWI, and the 50th and 75th percentile values of EPI-DWI (P = 0.29). CONCLUSION: The image quality of TSE-DWI was better than that of EPI-DWI. DCIS lesions were distinguished from IDC lesions with a wider range of percentile values in TSE-DWI than in EPI-DWI, although diagnostic performance was not significantly different between the techniques.

The pilT gene contributes to type III ExoS effector injection into epithelial cells in Pseudomonas aeruginosa.

A type IV pilus filament, mainly composed of PilA, is retracted by the driving power generated by PilT and PilU ATPases. pilA is required for injection of type III ExoS effectors into epithelial cells thereby facilitating Pseudomonas aeruginosa penetration through the epithelial barrier by impairing the defense function of tight junctions. Here, we examined whether the pilT and pilU of the P. aeruginosa PAO1 strain are required for ExoS injection into epithelial cells. We measured the quantity of ExoS injected into epithelial cells, and found that within such cells its quantity decreased by 80% (ΔpilA strain), 75% (ΔpilT strain), and 30% (ΔpilU strain) compared with the wild-type strain. pilT deficiency decreased the disruption of human epithelial colorectal adenocarcinoma (Caco-2) cell monolayers to the same extent as that of pilA and exoS deficiency, whereas pilU deficiency decreased disruption of the monolayers less than deficiency of the other genes. pilT and pilU deficiency decreased bacterial penetration of the Caco-2 cell monolayers to the same level as pilA and exoS deficiency. Our data showed that the pilU gene expression level was reduced in the PAO1 strain after adhesion to Caco-2 cell surfaces, but the expression levels of the pilA and pilT genes did not change. We conclude that P. aeruginosa injects ExoS into cells through the function of type IV pilus retraction, and that pilT makes a greater contribution to this process than pilU.

Interplay between two myogenesis-related proteins: TBP-interacting protein 120B and MyoD.

Gene expression in myogenesis is governed by multiple myogenic factors including MyoD. Previously, we demonstrated that TBP-interacting protein 120B (TIP120B) promotes in vitro myogenesis through its anti-ubiquitination ability. In this study, we investigated interplay between MyoD and TIP120B. Mouse C2C12 cells subjected to myotube differentiation contained increased amounts of TIP120B and MyoD. Dexamethasone, which inhibits myogenic signaling, decreased the amounts of those proteins. Mouse and human TIP120B promoters, which carry multiple E-box motifs, were potentiated by MyoD. In the human TIP120B, a proximal E-box binds to MyoD in vitro and exhibits MyoD-dependent transcription activation function. Expression of the endogenous TIP120B gene was correlated with the level of MyoD in different types of muscle-related cells. Furthermore, MyoD binds specifically to a proximal E-box-carrying promoter region in chromatin. Proteasome-sensitive MyoD was increased and decreased by overexpression and knockdown of TIP120B, respectively. Moreover, stability of MyoD was increased by TIP120B. The results suggest that MyoD and TIP120B potentiate each other at gene expression and post-translation levels, respectively, which may promote myogenesis cooperatively.