Predictive significance of breast-specific gamma imaging for upstaging core-needle biopsy-detected ductal carcinoma in situ to invasive cancer

Abstract

Objective

We evaluated the significance of breast-specific gamma imaging (BSGI) for determination of upstaging to invasive cancer from preoperative ductal carcinoma in situ (DCIS).

Methods

This study enrolled 168 patients with 175 breast lesions diagnosed as DCIS on core-needle biopsy that subsequently underwent preoperative BSGI between September 2011 and October 2017. Both qualitative and quantitative analyses using tumor-to-normal background ratio (TNR) and coefficient of variation (COV) were performed, and the predictive significance for upstaging to invasive cancer was investigated. We also sought to identify clinicopathological factors associated with upstaging and their relation to BSGI findings.

Results

Fifty-eight lesions (33.1%) were confirmed to be invasive breast cancer after the final surgical approach. On univariate analysis, tumor size based on ultrasonography (US), hormone status, histologic grade, Breast Imaging Reporting and Data System category, comedo-necrosis, Ki-67 expression, and BSGI findings were associated with upstaging to invasive cancer. Tumor size > 2.0 cm (p = 0.005), Ki-67 expression > 8% (p < 0.001), qualitative BSGI findings (p = 0.020), and COV > 30.44 (p = 0.022) were independently associated with upstaging after multiple regression analysis.

Conclusion

BSGI is a useful imaging modality for predicting upstaging to invasive breast cancer from DCIS on core-needle biopsy in conjunction with US tumor size and Ki-67 expression.

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Automatic bladder segmentation from CT images using deep CNN and 3D fully connected CRF-RNN

Abstract

Purpose

Automatic approach for bladder segmentation from computed tomography (CT) images is highly desirable in clinical practice. It is a challenging task since the bladder usually suffers large variations of appearance and low soft-tissue contrast in CT images. In this study, we present a deep learning-based approach which involves a convolutional neural network (CNN) and a 3D fully connected conditional random fields recurrent neural network (CRF-RNN) to perform accurate bladder segmentation. We also propose a novel preprocessing method, called dual-channel preprocessing, to further advance the segmentation performance of our approach.

Methods

The presented approach works as following: first, we apply our proposed preprocessing method on the input CT image and obtain a dual-channel image which consists of the CT image and an enhanced bladder density map. Second, we exploit a CNN to predict a coarse voxel-wise bladder score map on this dual-channel image. Finally, a 3D fully connected CRF-RNN refines the coarse bladder score map and produce final fine-localized segmentation result.

Results

We compare our approach to the state-of-the-art V-net on a clinical dataset. Results show that our approach achieves superior segmentation accuracy, outperforming the V-net by a significant margin. The Dice Similarity Coefficient of our approach (92.24%) is 8.12% higher than that of the V-net. Moreover, the bladder probability maps performed by our approach present sharper boundaries and more accurate localizations compared with that of the V-net.

Conclusion

Our approach achieves higher segmentation accuracy than the state-of-the-art method on clinical data. Both the dual-channel processing and the 3D fully connected CRF-RNN contribute to this improvement. The united deep network composed of the CNN and 3D CRF-RNN also outperforms a system where the CRF model acts as a post-processing method disconnected from the CNN.

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Detoxification of U(VI) by Paecilomyces catenlannulatus investigated by batch, XANES and EXAFS techniques

Publication date: September 2018
Source:Journal of Environmental Radioactivity, Volume 189
Author(s): Fengbo Li, Xiaoyu Li, Pu Cui
Paecilomyces catenlannulatus (P. catenlannulatus) as a genus of entomogenous fungus presented a variety of surface reactive groups by batch characterizations. The detoxification of U(VI) by P. catenlannulatus was investigated under different water chemistry (pH, incubation time, foreign anions and U(VI) concentration) by batch techniques. Approximately 75% of U(VI) was reduced to U(IV) (i.e., U^(IV)O2(s)) by P. catenlannulatus at pH 5.5 and 7 days under glovebox conditions, therefore the formation of precipitates decreased the toxicity of U(VI) for P. catenlannulatus. In addition, phosphate facilitate the U(VI) reduction, whereas carbonate and sulfate inhibited the U(VI) reduction. The activities of catalase (CAT), superoxide dismutase (SOD) and glutathione (GSH) level were stimulated exposure to 1-30 mg/L U(VI), indicating that CAT, SOD and GSH were antagonized for the oxidant stress derived from U(VI) at low concentrations. According to XPS and XANES analysis, the occurrence of U(IV) revealed the reduction of adsorbed U(VI) to U(IV) by P. catenlannulatus. The results of EXAFS analysis indicated that the fitting of U-O and U-U shell for U-loaded P. catenlannulatus was similar to that of U^(IV)O2(s)). The formation of U-bearing precipitates decreased the toxicity of U(VI) for P. catenlannulatus. These findings indicated that P. catenlannulatus is capable to detoxify U(VI) by extracellar/intracellar defense systems. Therefore, P. catenlannulatus can be utilized as a promising bioadsorbents for remediation of uranium-contaminated wastewater in environmental cleanup.



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Three-Dimensional Black Blood Contrast Enhanced Magnetic Resonance Imaging in Patients with Acute Ischemic Stroke and Negative Susceptibility Vessel Sign

Publication date: Available online 17 March 2018
Source:European Journal of Radiology
Author(s): Sung Hyun Baik, Hyo Sung Kwak, Seung Bae Hwang, Gyung Ho Chung
PurposeThe purpose of this study was to evaluate the enhancement patterns of three-dimensional (3D) black blood (BB) contrast enhanced magnetic resonance (MR) imaging in acute stroke patients with negative susceptibility vessel sign (SVS).Materials and methodsFrom January 2014 to August 2016 we retrospectively reviewed MR imaging and MR angiography findings of patients who presented with acute stroke symptoms of less than 24 h duration. For the 394 patients enrolled, we assessed the frequency of patients who exhibited negative SVS on susceptibility weighted MR imaging (SWI) and positive enhancement in 3D BB contrast enhanced MR imaging. We subdivided the enrolled group according to whether the MR angiography findings suggested stenosis (stenosis group) or occlusion (occlusion group). Enhancement patterns on BB contrast enhanced MR imaging were compared between the two groups according to several qualitative parameters: intensity (weak or strong), morphology (linear/eccentric or round/concentric), length (focal or segmental) and multiplicity (single or multiple).ResultsSixty-two of 394 patients (15.7%) showed positive findings on BB contrast-enhanced MR imaging with negative SVS. Forty-two patients were classified into the stenosis group, and 20 patients were assigned to the occlusion group. Enhancement patterns of the stenosis group showed weak intensity, linear or eccentric morphology and focal lesion length on BB contrast enhanced MR imaging, compared to the occlusion group (P < 0.001). In contrast, enhancement patterns of the occlusion group showed strong intensity, round or concentric morphology and longer segmental lesion length, compared to the stenosis group (P < 0.001).ConclusionThree-dimensional BB contrast enhanced MR imaging in acute stroke patients with stenotic lesions and negative SVS shows enhancement patterns of linear or eccentric morphology and shorter, more focal lesions.



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Imaging cellularity in benign and malignant peripheral nerve sheath tumors: Utility of the “target sign” by Diffusion Weighted Imaging

Publication date: Available online 16 March 2018
Source:European Journal of Radiology
Author(s): Shivani Ahlawat, Laura M. Fayad
ObjectiveTo determine the utility of "target sign" on diffusion weighted imaging (DWI) and apparent diffusion coefficient (ADC) mapping for peripheral nerve sheath tumor (PNST) characterization.Materials and MethodsThis IRB–approved, HIPAA–compliant study retrospectively reviewed the MR imaging (comprised of T2- FS, DWI (b-values 50, 400, 800 s/mm²and ADC mapping), and static contrast-enhanced (CE) T1-W imaging of 42 patients (mean age: 40 years (range 8–68 years), 48% (20/42) females) with 15 malignant PNSTs (MPNSTs) and 33 benign PNSTs (BPNSTs). MPNSTs were histologically confirmed while BPNSTs were histologically-proven or with stable clinical and imaging appearance for at least 12 months. Two radiologists assessed imaging characteristics (size, signal intensity, heterogeneity, perilesional edema or enhancement) and the presence or absence of "target sign," on each sequence. A "target sign" was defined as a biphasic pattern of peripheral hyperintensity and homogeneous central hypointensity. Descriptive statistics are reported. Cohen's κ statistic or interclass correlation coefficient (ICC) were used to evaluate interobserver agreement between two observers. Univariate and multiple logistic regression analysis were performed to identify MRI features with predictive values.ResultsMPNSTs were larger than BPNSTs (6.3 ± 2.5 cm vs 3.5 ± −2.1 cm, p = 0.0002), had perilesional edema (87%(13/15) vs 18%(6/33), p < 0.0001), heterogeneous enhancement (71%(10/14) vs 13%(4/31), p = 0.0001) and perilesional enhancement (79%(11/14) vs 18%(6/31), p = 0.0001), respectively. The "target sign" was present in: 24%(8/33) BPNSTs vs 0/15 MPNST on T2-FS (p = 0.26); 39%(13/33) BPNSTs vs 20%(3/15) MPNST on DWI using b-value = 50 s/mm² (p = 0.5); 55%(18/33) BPNSTs vs 6%(1/15) MPNST on DWI using b-value = 400 s/mm² (p = 0.002); 48%(16/33) BPNSTs vs 6%(1/15) MPNST on DWI using b-value = 800 s/mm² (p = 0.005) and 64%(21/33) benign vs 0/15 MPNST on ADC mapping(p < 0.0001). By CE-T1 imaging, 32%(10/31) BPNSTs and 7%(1/14) MPNST had a target sign(p = 0.07). The odds of an MPNST in cases with minimum ADC ≤ 1.0 × 10(−3) mm(2)/s are 150 times higher than in cases with ADC > 1.0 × 10(−3).ConclusionIn this explorative study, a "target sign" suggests a benign PNST and is more often visible on DWI using high b-values and ADC maps compared with anatomic sequences.



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Role of PROPELLER-DWI of the prostate in reducing distortion and artefact from total hip replacement metalwork

Publication date: Available online 16 March 2018
Source:European Journal of Radiology
Author(s): Marcin Czarniecki, Iztok Caglic, James T. Grist, Andrew B. Gill, Kamil Lorenc, Rhys A. Slough, Andrew N. Priest, Tristan Barrett
ObjectiveTo compare image quality, artefact, and distortion in standard echo-planar imaging (EPI) with periodically rotated overlapping parallel lines with enhanced reconstruction (PROPELLER) for prostate magnetic resonance imaging (MRI) diffusion-weighted imaging (DWI) in patients with previous total hip replacement (THR).Methods21 male subjects with a clinical suspicion for, or known prostate cancer and previous THR were scanned at 1.5 tesla using a phased-array body coil. DWI was obtained using single-shot EPI and PROPELLER techniques using fat saturation (PROPELLER-DWI-FS), and without (PROPELLER-DWI-NFS). Image quality (the overall impression of diagnostic quality) was compared to T2-weighted (T2WI) imaging using a 5-point Likert scale, with diffusion sequences additionally scored for artefact and distortion according to a 4-point scale, with artefact defined as the amount of prostate affected and distortion as the degree of warping of the organ. The T2W and DW image volumes were compared to produce quantitative distortion maps. A two-sample Wilcoxon test compared the qualitative scores, with inter-reader variability calculated using Cohen's kappa.Results21 patients were included in the study, with an average age of 70.4 years and PSA 9.2 ng/mL. Hip metalwork was present bilaterally in 3 patients, left-sided in 9, and right-sided in 9.PROPELLER-DWI-FS significantly improved image quality (p < 0.01) and reduced distortion (p < 0.01) when compared to standard EP-DWI. Artefact was not shown to be significantly improved. The last 5 patients in the study were additionally imaged with PROPELLER-DWI-NFS, which resulted in a significant reduction in artefact compared to EP-DWI (p < 0.05). Quantitative distortion was significantly lower compared to EP-DWI for both PROPELLER with fat saturation (p < 0.01) and without fat saturation (p < 0.01).ConclusionPROPELLER-DWI demonstrates better image quality and decreases both artefact and distortion compared to conventional echo planar sequences in patients with hip metalwork.



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Editorial Board (Pantone 286 C)

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