Introduction
Magnetic resonance imaging (MRI) has played an increasingly major role in the evaluation of patients with prostate cancer, although prostate MRI presents several technical challenges. ...Newer techniques, such as deep learning (DL), have been applied to medical imaging, leading to improvements in image quality. Our goal is to evaluate the performance of a new deep learning-based reconstruction method, “DLR” in improving image quality and mitigating artifacts, which is now commercially available as AIR
TM
Recon DL (GE Healthcare, Waukesha, WI). We hypothesize that applying DLR to the T2WI images of the prostate provides improved image quality and reduced artifacts.
Methods
This study included 31 patients with a history of prostate cancer that had a multiparametric MRI of the prostate with an endorectal coil (ERC) at 1.5 T or 3.0 T. Four series of T2-weighted images were generated in total: one set with the ERC signal turned on (ERC) and another set with the ERC signal turned off (Non-ERC). Each of these sets then reconstructed using two different reconstruction methods: conventional reconstruction (Conv) and DL Recon (DLR): ERC
DLR
, ERC
Conv
, Non-ERC
DLR
, and Non-ERC
Conv
. Three radiologists independently reviewed and scored the four sets of images for (i) image quality, (ii) artifacts, and (iii) visualization of anatomical landmarks and tumor.
Results
The Non-ERC
DLR
scored as the best series for (i) overall image quality (
p
< 0.001), (ii) reduced artifacts (
p
< 0.001), and (iii) visualization of anatomical landmarks and tumor.
Conclusion
Prostate imaging without the use of an endorectal coil could benefit from deep learning reconstruction as demonstrated with T2-weighted imaging MRI evaluations of the prostate.
Glutathione transferases (GSTs), the ancient, ubiquitous and multi-functional proteins, play significant roles in development, metabolism as well as abiotic and biotic stress responses in plants. ...Wheat is one of the most important crops, but the functions of GST genes in wheat were less studied.
A total of 330 TaGST genes were identified from the wheat genome and named according to the nomenclature of rice and Arabidopsis GST genes. They were classified into eight classes based on the phylogenetic relationship among wheat, rice, and Arabidopsis, and their gene structure and conserved motif were similar in the same phylogenetic class. The 43 and 171 gene pairs were identified as tandem and segmental duplication genes respectively, and the Ka/Ks ratios of tandem and segmental duplication TaGST genes were less than 1 except segmental duplication gene pair TaGSTU24/TaGSTU154. The 59 TaGST genes were identified to have syntenic relationships with 28 OsGST genes. The expression profiling involved in 15 tissues and biotic and abiotic stresses suggested the different expression and response patterns of the TaGST genes. Furthermore, the qRT-PCR data showed that GST could response to abiotic stresses and hormones extensively in wheat.
In this study, a large GST family with 330 members was identified from the wheat genome. Duplication events containing tandem and segmental duplication contributed to the expansion of TaGST family, and duplication genes might undergo extensive purifying selection. The expression profiling and cis-elements in promoter region of 330 TaGST genes implied their roles in growth and development as well as adaption to stressful environments. The qRT-PCR data of 14 TaGST genes revealed that they could respond to different abiotic stresses and hormones, especially salt stress and abscisic acid. In conclusion, this study contributed to the further functional analysis of GST genes family in wheat.
Purpose
To explore whether body composition and/or sarcopenia are associated with liver hypertrophy following portal vein embolization (PVE) in patients with colorectal liver metastases (CLM).
...Methods
Patients with CLM who underwent right PVE prior to a planned right hepatectomy were identified from the institutional liver database from 2004 to 2014. Patients were excluded due to previous liver-directed therapy/hepatectomy, right PVE + segment IV embolization, or planned 2-stage hepatectomy. Advanced imaging software was used to measure body compartment volumes (cm
2
), which were standardized to height (m
2
) to create an index: skeletal muscle index (SMI), subcutaneous adipose index (SAI), and visceral adipose index (VAI). SMI, gender, and body mass index (BMI) were used to define sarcopenia. The main outcome of interest was hypertrophy of the future liver remnant (FLR) following PVE, which was reported as degree of hypertrophy (DH) and kinetic growth rate (KGR).
Results
Patients were evenly divided into three KGR groups: lower third (KGR:0.7–2.0%), middle third (KGR:2.0–4.1%), and upper third (KGR:4.2–12.3%). Patients in the lower third KGR group had a lower VAI (31.0 vs 53.0 vs 54.5 cm
2
/m
2
,
p
= 0.042) and were more commonly sarcopenic (60%) compared to the upper third (20%,
p
= 0.025). Eighteen patients (40%) met criteria for sarcopenia. Sarcopenic patients had a lower VAI (29.1 vs 57.4 cm
2
/m
2
,
p
= 0.004), lesser degree of hypertrophy (8.3% vs 15.2%,
p
= 0.009), and lower KGR (2.0% vs 4.0%,
p
= 0.012).
Conclusion
Sarcopenia and associated body composition indices are strongly associated with clinically relevant impaired liver regeneration, which may result in increased liver-specific complications following hepatectomy for CLM.
Purpose
To determine if a reduced‐field‐of‐view (rFOV) diffusion intravoxel incoherent motion (IVIM) sequence can differentiate the imaging characteristics of tumors with microsatellite instability ...(MSI) from those that are microsatellite stable (MSS) in patients with clinical FIGO stage IA endometrial cancer and if MRI can be used to determine MSI status.
Materials and Methods
Sagittal rFOV diffusion‐weighted images were obtained in 12 patients on a 3T scanner using six b‐values (0, 50, 100, 150, 200, and 600). These images were used to derive apparent diffusion coefficient (ADC), true diffusion coefficient (Dt), pseudodiffusion (D*), and perfusion fraction (f). Regions of interest (ROIs) were drawn on the dynamic contrast‐enhanced magnetic resonance imaging (MRI) sequence on an Advantage Windows workstation and were copied to the same location on IVIM‐derived images. The ROI mean of these images was recorded and compared with the microsatellite status. The depth of myometrial invasion and IVIM‐derived parameters were tabulated by microsatellite status. The Wilcoxon rank sum test was used to compare T1 postcontrast images and IVIM‐derived images and microsatellite status.
Results
Six patients had MSS tumors and six had MSI tumors. MSS tumors had a significantly higher ADC value (P = 0.03) and Dt (P = 0.045) than the MSI tumors. There was no association between < and ≥ 50% depth of myometrial invasion (measured on pathology and MRI analysis) and MSI stability P > 0.99.
Conclusion
IVIM, ADC and Dt may be able to determine microsatellite status noninvasively in patients with clinical FIGO stage I endometrial cancer.
Level of Evidence: 1
J. Magn. Reson. Imaging 2017;45:1216–1224
Purpose
To evaluate the incremental value of diffusion‐weighted imaging (DWI) to conventional MR imaging (CMRI) to predict ipsilateral metastatic axillary lymphadenopathy in patients with newly ...diagnosed breast cancer.
Subjects and methods
In an IRB approved retrospective single‐institution study, newly diagnosed consecutive breast cancer patients with pathological verification of axillary lymph node (LN) status who had undergone breast MR imaging, including DWI as part of their standard MRI between August 1, 2010, and December 31, 2010, were reviewed. Lesion size, tumor grade, and tissue prognostic factors were noted. Ipsilateral axillary LNs were evaluated using morphological criteria on CMRI. Apparent diffusion coefficient (ADC) values of suspicious ipsilateral LNs were obtained and compared with ADC values of contralateral benign axillary LNs. Receiver operating characteristic curves and multivariate logistic regression analyses were used using pathology as the gold standard.
Results
Eighty‐five eligible patients were identified, with surgical pathology revealing 34 patients (40%) who had malignant and 51 (60%) had benign ipsilateral axillae. The sensitivity of CMRI was 79%, with a specificity of 81%, a positive predictive value (PPV) of 65%, and a negative predictive value (NPV) of 89%. On DWI, the mean ADC value was significantly lower for metastatic LNs (0.89 ± 0.18 × 10−3 mm2/s) than for benign ipsilateral LNs (1.41 ± 0.21 × 10−3 mm2/s; P < 0.0001). Using a cutoff ADC value of 0.985 × 10−3 mm2/s, yielded improved sensitivity, specificity, PPV, and NPV of 83%, 98%, 95%, and 93%, respectively.
Conclusion
Apparent diffusion coefficient values increase the specificity of CMRI for predicting ipsilateral axillary LN metastases in patients with newly diagnosed breast cancer.
Oncological diseases account for a significant portion of the burden on public healthcare systems with associated costs driven primarily by complex and long-lasting therapies. Through the ...visualization of patient-specific morphology and functional-molecular pathways, cancerous tissue can be detected and characterized non-invasively, so as to provide referring oncologists with essential information to support therapy management decisions. Following the onset of stand-alone anatomical and functional imaging, we witness a push towards integrating molecular image information through various methods, including anato-metabolic imaging (e.g., PET/CT), advanced MRI, optical or ultrasound imaging.This perspective paper highlights a number of key technological and methodological advances in imaging instrumentation related to anatomical, functional, molecular medicine and hybrid imaging, that is understood as the hardware-based combination of complementary anatomical and molecular imaging. These include novel detector technologies for ionizing radiation used in CT and nuclear medicine imaging, and novel system developments in MRI and optical as well as opto-acoustic imaging. We will also highlight new data processing methods for improved non-invasive tissue characterization. Following a general introduction to the role of imaging in oncology patient management we introduce imaging methods with well-defined clinical applications and potential for clinical translation. For each modality, we report first on the status quo and, then point to perceived technological and methodological advances in a subsequent status go section. Considering the breadth and dynamics of these developments, this perspective ends with a critical reflection on where the authors, with the majority of them being imaging experts with a background in physics and engineering, believe imaging methods will be in a few years from now.Overall, methodological and technological medical imaging advances are geared towards increased image contrast, the derivation of reproducible quantitative parameters, an increase in volume sensitivity and a reduction in overall examination time. To ensure full translation to the clinic, this progress in technologies and instrumentation is complemented by advances in relevant acquisition and image-processing protocols and improved data analysis. To this end, we should accept diagnostic images as "data", and - through the wider adoption of advanced analysis, including machine learning approaches and a "big data" concept - move to the next stage of non-invasive tumour phenotyping. The scans we will be reading in 10 years from now will likely be composed of highly diverse multi-dimensional data from multiple sources, which mandate the use of advanced and interactive visualization and analysis platforms powered by Artificial Intelligence (AI) for real-time data handling by cross-specialty clinical experts with a domain knowledge that will need to go beyond that of plain imaging.
Purpose
Sarcopenia is an independent prognostic indicator for hepatocellular carcinoma (HCC). Our objective was to determine the effect of sarcopenia on response to systemic targeted therapy in ...patients with advanced HCC.
Materials and methods
This was a retrospective, Institutional Review Board approved study of 36 patients on systemic targeted therapy with immune checkpoint blockade (
n
= 25) or tyrosine kinase inhibitor (
n
= 11) for biopsy-proven advanced HCC. Skeletal muscle index (SMI) was calculated from erector spinae muscle area (SMA) at the level of T12 on pretreatment CT: SMI = SMA (cm
2
)/height (m
2
). SMI was compared to treatment response defined as overall survival ≥ 1 year (nonsurgical patients) or > 50% HCC necrosis (surgical patients). Receiver operating characteristic curve and area under the curve was used for analysis with
p
< 0.05 for statistical significance.
Results
Median age of men and women was 66.5 years (range 32–83) and 70 years (range 54–78), respectively. Liver disease etiology was nonalcoholic steatohepatitis (
n
= 9), hepatitis C (
n
= 10), hepatitis B (
n
= 5), alcohol (
n
= 3) and unknown (
n
= 9). Mean (± SD) height and SMI for men were 1.7 m (± 0.1) and 11.4 (± 3.6); values for women were 1.7 m (± 0.1) and 8.2 (± 1.9). Treatment was withdrawn in five patients due to treatment intolerance. Response occurred in 10/31 (32.3%) patients (23 men, 8 women). T12SMI correlated with treatment response using a threshold of 7.21-8.23 for women (AUC = 1;
p
= 0.037), and 11.47 for men (AUC = 0.83;
p
= 0.015); correlation was increased for men ≥ 60 years, (AUC = 0.87;
p
= 0.023).
Conclusion
Sarcopenia was associated with reduced survival and HCC necrosis in patients treated with systemic targeted therapy.
Clinical relevance
Sarcopenia may help in predicting outcomes to targeted therapy in advanced HCC.
Purpose
To determine whether staging pelvic magnetic resonance imaging (MRI) can distinguish malignant mixed Müllerian tumor (MMMT) from EC.
Methods
Thirty-seven treatment-naïve patients with ...histologically proven uterine MMMT and 42 treatment-naïve patients with EC, treated at our institution, were included in our retrospective study. Staging pelvic MRI scans were reviewed for tumor size, prolapse through cervical os, and other features. Time-intensity curves for tumor and surrounding myometrium regions of interest were generated, and positive enhancement integral (PEI), maximum slope of increase (MSI), and signal enhancement ratio (SER) were measured. The Fisher's exact test or Wilcoxon rank-sum test was used to compare characteristics between disease groups. Multivariate and univariate logistic regression models were used to distinguish MMMT from EC. Receiver operating characteristic analysis and the area under the curve (AUC) were used to evaluate prediction ability.
Results
MMMTs were larger than ECs with higher rate of tumor prolapse and more heterogeneous tumor enhancement compared to ECs. During the late phase of contrast enhancement, 100% of ECs, but only 84% of MMMTs, had lower signal intensity than the myometrium. Threshold PEI ratio ≥ 0.67 predict MMMT with 76% sensitivity, 84%, specificity and 0.83 AUC. Threshold SER ≤ 125 predict MMMT with 90% sensitivity, 50% specificity, and 0.72 AUC.
Conclusion
MMMTs may show more frequent tumor prolapse, more heterogeneous enhancement, delayed iso- or hyper-enhancement, higher PEI ratios, and lower tumor SERs compared with EC. MRI can be used as a biomarker to distinguish MMMT from EC based on the enhancement pattern.
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