Tumor Visibility Research Articles

Transarterial ethiodised oil marking before CT-guided renal cryoablation: evaluation of tumour visibility in various renal cell carcinoma subtypes

To evaluate ethiodised oil retention of transarterial embolisation using ethiodised oil (ethiodised oil marking) before computed tomography (CT)-guided percutaneous cryoablation (PCA) according to renal cell carcinoma (RCC) subtype. Ethiodised oil marking was performed 1-3 days before PCA in 99 patients with 99 RCCs from 2016 to 2020. Ethiodised oil retention on CT images was evaluated retrospectively and CT attenuation values in the tumour were measured. Regions of interest (ROI) were placed on the tumours to calculate: average (ROI-average), maximal (ROI-max), minimum (ROI-min), and standard deviation (ROI-SD). Qualitative scores comprising a five-point scale (5, excellent; 1, poor) were evaluated for the retention scores (RS) of ethiodised oil in the tumour (ethiodised oil-RS) and the visualisation scores (VS) of the boundary between the tumour and renal parenchyma (boundary-VS). The histological subtypes comprised clear cell (ccRCC; n=85), papillary (pRCC; n=6), and chromophobe/oncocytoma renal cell carcinoma (chrRCC; n=8). The mean ROI-average, ROI-max, and ROI-SD were significantly higher in ccRCCs than in chrRCCs and pRCCs (p<0.05). The mean ethiodised oil-RS was significantly lower in pRCCs than in ccRCCs (p=0.039), and the mean boundary-VS was >4 in all subtypes. Even with poor intratumour ethiodised oil retention (n=6), sufficient boundary-VS was obtained due to "inverted marking." All PCA procedures were completed without additional intravenous contrast material injection at the time of PCA. Regardless of the tumour subtypes, ethiodised oil marking aids in visualising the boundary between the tumour and parenchyma on non-contrast CT in PCA.

A Novel Hybrid Deep Learning Framework for Detection and Categorization of Brain Tumor from Magnetic Resonance Images

Cellular abnormality leads to brain tumour formation. This is one of the foremost reasons of adult death all over the world. The typical size of a brain tumour increases within 25 days due to its rapid growth. Early brain tumour diagnosis can save millions of lives. For the purpose of early brain tumour identification, an automatic method is necessary. MRI brain tumour detection improves the survival of patients. Tumour visibility is improved in MRI, which facilitates subsequent treatment. To distinguish between brain MRI images with tumour and images without tumour is suggested in this paper. Many approaches in the field of machine learning including Support Vector Machine, Artificial Neural Networks, and KNN classifier have been developed for solving these issues. But these methods are time consuming, inefficient and require complex procedures. For a Computer Assisted Diagnosis system to aid physicians and radiologists in the identification and categorization of tumours, artificial intelligence is used. Deep learning has demonstrated an encouraging efficiency in computer vision systems over the past decade. In this paper, identification and classification of brain tumour from MR images employing BGWO-CNN-LSTM method is proposed. The proposed method on a testing set with 6100 MRI images of four different kinds of brain tumours is utilized. In comparison to earlier research on the same data set, the suggested approach achieved 99.74% accuracy, 99.23% recall and 99.54% specificity which are greater than the other techniques.

Downregulation of CD16 Surface Expression on NK Cells Is a Favorable Prognostic Factor in Acute Myeloid Leukemia

Introduction Acute myeloid leukemia (AML) is a malignant hematological disease characterized by poor patient outcomes and limited chemotherapy options. The rapid advancement of immunotherapy has pushed natural killer (NK) cells into the spotlight. NK cells can eliminate tumor cells through CD16-mediated antibody-dependent cellular cytotoxicity (ADCC). Previous studies have found that downregulation of CD16 occurs after coculture with malignant targets, but the effects on ADCC by NK cells is less clear. Several studies have shown that blocking CD16 cleavage increases NK cell attachment to antibody-coated target cells, degranulation (Romee et al., 2013), whereas others, have reported that blocking CD16 cleavage either did not affect ADCC and limited their ability to kill in a sequential manner (Srpan et al., 2018). This uncertainty stems from a disparity between experimental methods in vitro. Therefore, understanding the clinical significance of downregulation of CD16 surface expression on NK cells is crucial. Methods Patients diagnosed with de novo AML between 2020 and 2022 were enrolled in the study. All patients were treated in accordance with NCCN Clinical Practice Guidelines in Oncology of AML (Version 3, 2020). Bone marrow samples were collected at month 0, month 1, months 1-3, months 3-6 and months 6-12 after therapy. Number of NK (CD3-CD56+) cells and their subsets (CD16+ and CD16-) were analyzed by flow cytometry. Based on the 12-month prognosis, the patients were assigned to favorable prognosis group (complete response and survival) or unfavorable prognosis group (relapse or death). Results Totally 188 AML patients (108 males, 80 females) with a mean age of 45.5±17.9 years in this study. At month 0, month 1, months 1-3, months 3-6 and months 6-12, the mean percentage of NK cells in the bone marrow were 11.95%±0.63%，12.14%±1.40%，13.02%±1.31%,13.22%±1.25,13.30%±1.50%, respectively. There was a trend towards increased, but it was not statistically significant (P=0.12, Fig.1). There were 122 patients in the favorable prognosis group and 66 patients in the unfavorable prognosis group. The mean percentage of NK cells expressing CD16 in the bone marrow between the two groups were 74.44%±2.26% vs 74.70±2.98% at month 0 (P=0.94), 53.70±6.80% vs 52.77±10.33% at month 1 (P=0.94), 50.85±5.04% vs 71.85±6.21% at months 1-3 (P<0.01), 38.78±5.74% vs 47.05±15.05% at months 3-6 (P=0.59), and 22.94±5.70% vs 78.28±9.92% at months 6-12 (P<0.01). The level of CD16 surface expression on NK cells in the favorable prognosis group showed gradually trend of decrease (P=0.02), while it increased at months 1-3 and months 6-12 in the unfavorable prognosis group (P<0.01). The two significant peaks correspond to adverse event. Conclusions CD16 surface expression on NK cells was down-regulated in AML patients, and was markedly related to a favorable prognosis. It is similar to the previous conclusion of Srpan et al. These results indicate that CD16 may be used as a potential biomarker to predict prognosis for AML patients. Future studies will explore the visibility of other tumor, and shed new light on the development of immunological therapy for tumors. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Sensitivity of multiparametric MRI and targeted biopsy for detection of adverse pathologies (Cribriform gleason pattern 4 and intraductal carcinoma): Correlation of detected and missed prostate cancer foci with whole mount histopathology.

Accurate preoperative detection of prostate cancer (PCa) exhibiting "cribriform" morphology (intraductal carcinoma [IDC-P] or cribriform Gleason pattern 4 [CrP4]) is important as it is independently associated with a variety of adverse clinical outcomes. The sensitivity of multiparametric magnetic resonance imaging (mpMRI) in the detection of PCa exhibiting "cribriform" morphology remains controversial. A total of 117 eligible men with prospectively reported mpMRI who underwent in-bore MRI targeted biopsy followed by whole-mount radical prostatectomy (RP) were analyzed for lesion-level imaging-pathology correlation. Of the 206 PCa foci at RP (117 index and 89 non-index), 74% (152/206) were detected by mpMRI. Of the 54 tumors missed by mpMRI, most were non-index (98%, 53/54), grade group (GG) 1 (68%, 37/54) or GG 2 (26%, 14/54), with a median size of 1.0 cm (range, 0.7-1.5 cm), and non-cribriform morphology (96%, 52/54). Cribriform morphology was detected in 26% (53/206) of all tumors, and although targeted biopsies identified 96% (51/53) of these cancers, the cribriform component was depicted in only 45% (24/53). Of these, mpMRI detected all (100%, 44/44) index and 78% (7/9) of the non-index tumors. At univariable analysis, tumor size greater than 5 mm, % pattern 4 > 5%, cribriform morphology, zone (transition versus peripheral zone), and region (apex versus mid/base) were significantly associated with tumor visibility at mpMRI. At multivariable analysis, only tumor size, presence of any pattern 4, and peripheral zone remained significant predictors for visibility by mpMRI. At a lesion level, mpMRI offers high sensitivity for the detection of cribriform morphologies, however, the cribriform component is frequently missed by targeted biopsies. The MRI visibility is significantly associated with larger tumor size, presence of Gleason pattern 4, and peripheral zone location.

Confidence Region Identification and Contour Detection in MRI Image.

Tumour region extraction (RE) method identifies the area of interest in MR imaging as it also highlights tumour boundaries. Some other intensities are existing, they are not visible but have their existence in region, and this region is called growing region. Such region is to be tumour region. Due to the variation of intensities in MRI images, tumour visibility becomes uncleared. Tumour intensity variations (tumour tissues) mix with normal brain tissues. In the light of above circumstance, tumour growing region becomes challenge. The goal of work is to extract the region of interest with confidence. The objective of the study is to develop the region of interest of brain tumour MRI image method by using confidence score for identifying the variation of intensity. The significance of work is based on identification of region of interest (tumour region). Confidence score is measured through pattern of intensities of MRI image. Similar patterns of brain tumour intensities are identified. Each pattern of intensities is adjusted with certain scale, and then biggest blob is analysed. Various biggest area blobs are combined, and resultant biggest blob is formed. In fact, resultant area blob is a combination of different patterns. Each pattern is assigned with particular colour. These colours highlight the growing region. Further, a contour is detected around the tumour boundaries. With combination of region scale fitting and contour detection (CD), tumour boundaries are further separated from normal tissues. Hence, the confidence score (CS) is formed from CD. CS is further converted to confidence region (CR). Conversion to CR is performed though confidence interval (CI). CI is based on defined conditions. In such conditions, different probabilities are considered. Probability identifies the region. Source of region formation is pixels; these pixels highlight tumour core significantly. This CR is obtained through checking standard deviation and statistical evaluation using confidence interval. Hence, region-of-interest pixels are identifying the CR. CR is evaluated through 97% Dice over index (DOI), 94% Jacquard, MSE 1.24, and PSNR 17.45. Value of testing parameter from benchmark study was JI, DOI, and MSE, PSNR : JI was 31.5%, DOI was 47.3%, MSE was 2.5 dB, and PSNR was 40 dB. The parameters are measured for the complex images; contribution parameter classifies the mean pixel values and deviating pixel values, and the classification of the pixel value is like to be termed as intensities. Mentioned classification extracts the variation of intensity pixels accurately; then, algorithm is highlighting the region as compared to the normal tumour cells.

DIPG-47. TSO500ctDNA sequencing reveals oncogenic mutations and copy number variations in the liquid biome of children with diffuse midline glioma

BACKGROUND: Molecular profiling of childhood CNS tumors is critical for diagnosis and clinical management, yet tissue access is restricted due to sensitive neuroanatomical locations. Moreover, CNS tumors including diffuse midline glioma (DMG) exhibit mutational heterogeneity and clonal evolution, which cannot be captured by upfront diagnostic biopsy alone. To address the lack of tumor visibility, and tprovide opportunity for longitudinal sampling, we validated and optimized a commercially available deep sequencing platform for analysis of circulating tumor DNA (TSO500ctDNATM). METHODS: In a proof-of-concept study, we defined the sensitivity, specificity, and clinical relevance of our novel ctDNA platform via analysis of paired tissue, CSF, and blood from children with DMG (n=10). Paired samples were assessed for concordance and sequencing results were compared to digital droplet PCR (ddPCR) detection of prognostic H3K27M mutation. RESULTS: DMG associated mutations in genes including H3-3A, H3C2, TP53, and ACVR1 were detected in ctDNA, including in CSF samples with low (<5ng) starting DNA input. Of 9 H3K27M mutations identified in tumor, 8 were present in CSF and 3 in plasma/serum, for a positive percent agreement with tumor results of 89% and 33%, respectively. Among CSF samples, H3.3K27M was detected in 6/6 cases, and H3.1K27M in 2/3 cases, with variant allele frequencies comparable to ddPCR results. CNVs including PDGFRA, KIT, and MDM4 gains were detected in CSF and paired tumor. Low frequency events including ACVR1, PIK3CA activating mutations and KRAS amplification were detected in CSF but absent from paired tumor, indicating tissue heterogeneity. Strategies to optimize ctDNA detection, including optimization of ctDNA isolation and adjustment of library QC metrics, were identified. CONCLUSION: Targeted ctDNA deep sequencing is feasible, can inform on clinically relevant tumor mutation and CNV profiling, and provides an opportunity for longitudinal monitoring of tumor genomic evolution in the liquid biome of children with CNS tumors.

A simulated comparison of lung tumor target verification using stereoscopic tomosynthesis or radiography.

Mobile lung tumors are increasingly being treated with ablative radiotherapy, for which precise motion management is essential. In-room stereoscopic radiography systems are able to guide ablative radiotherapy for stationary cranial lesions but not optimally for lung tumors unless fiducial markers are inserted. We propose augmenting stereoscopic radiographic systems with multiple small x-ray sources to provide the capability of imaging with stereoscopic, single frame tomosynthesis. In single frame tomosynthesis, nine x-ray sources are placed in a 3×3 configuration and energized simultaneously. The beams from these sources are collimated so that they converge on the tumor and then diverge to illuminate nine non-overlapping sectors on the detector. These nine sector images are averaged together and filtered to create the tomosynthesis effect. Single frame tomosynthesis is intended to be an alternative imaging mode for existing stereoscopic systems with a field of view that is three times smaller and a temporal resolution equal to the frame rate of the detector. We simulated stereoscopic tomosynthesis and radiography using Monte Carlo techniques on 60 patients with early-stage lung cancer from the NSCLC-Radiomics dataset. Two board-certified radiation oncologists reviewed these simulated images and rated them on a 4-point scale (1: tumor not visible; 2: tumor visible but inadequate for motion management; 3: tumor visible and adequate for motion management; 4: tumor visibility excellent). Each tumor was independently presented four times (two viewing angles from radiography and two viewing angles from tomosynthesis) in a blinded fashion over two reading sessions. The fraction of tumors that were rated as adequate or excellent for motion management (scores 3 or 4) from at least one viewing angle was 53% using radiography and 90% using tomosynthesis. From both viewing angles, the corresponding fractions were 7% for radiography and 48% for tomosynthesis. Readers agreed exactly on 62% of images and within 1 point on 98% of images. The acquisition technique was estimated to be 75 mAs at 120 kVp per treatment fraction assuming one verification image per breath, approximately one order of magnitude less than a standard dose cone beam CT. Stereoscopic tomosynthesis may provide a noninvasive, low dose, intrafraction motion verification technique for lung tumors treated by ablative radiotherapy. The system architecture is compatible with real-time video capture at 30 frames per second. Simulations suggest that most, but not all, lung tumors can be adequately visualized from at least one viewing angle.

Firefly Competitive Swarm Optimization Based Hierarchical Attention Network for Lung Cancer Detection

Lung cancer is a severe disease, which causes high deaths in the world. Earlier discovery of lung cancer is useful to enhance the rate of survival in patients. Computed Tomography (CT) is utilized for determining the tumor and identifying the cancer level in the body. However, the issues of CT images cause less tumor visibility areas and unconstructive rates in tumor regions. This paper devises an optimization-driven technique for classifying lung cancer. The CT image is utilized for determining the position of the tumor. Here, the CT image undergoes segmentation, which is performed using the DeepJoint model. Furthermore, the feature extraction is carried out, wherein features such as local ternary pattern-based features, Histogram of Gradients (HoG) features, and statistical features, like variance, mean, kurtosis, energy, entropy, and skewness. The categorization of lung cancer is performed using Hierarchical Attention Network (HAN). The training of HAN is carried out using proposed Firefly Competitive Swarm Optimization (FCSO), which is devised by combining firefly algorithm (FA), and Competitive Swarm Optimization (CSO). The proposed FCSO-based HAN provided effective performance with high accuracy of 91.3%, sensitivity of 88%, and specificity of 89.1%.

Radiofrequency ablation using real-time ultrasonography-computed tomography fusion imaging improves treatment outcomes for T1a renal cell carcinoma: Comparison with laparoscopic partial nephrectomy.

PurposeTo determine whether real-time ultrasonography–computed tomography (US-CT) fusion imaging can improve technical feasibility versus B-mode US and provide comparable outcomes of radiofrequency ablation (RFA) for T1a renal cell carcinoma (RCC) compared with laparoscopic partial nephrectomy (LPN).Materials and MethodsBetween June 2013 and August 2016, biopsy- or pathologically confirmed stage T1a RCCs were retrospectively reviewed. Of these, 39 cases were included in the RFA group, and 46 cases were included in the LPN group. In the RFA group, we evaluated tumor visibility and technical feasibility before RFA on a four-point scale on B-mode US and US-CT fusion images. After RFA, hospital days, creatinine value, complications, and disease-free survival rate were compared between the two groups. All results were analyzed by use of the Mann–Whitney U-test and Kaplan–Meier method.ResultsCompared with B-mode US alone, real-time US-CT fusion significantly improved the tumor visibility score and overall mean technical feasibility grade (p<0.001). The 5-year disease-free survival rate was 97.4% and 97.8% in the RFA and LPN groups, respectively, and there was no statistically significant difference between groups (p=0.1). Mean periprocedural creatinine levels were significantly lower in the RFA group than in the LPN group. The number of hospital days was shorter in the RFA group. Minor complications were present in 5.1% of the RFA group and 13.0% of the LPN group, with no major complications.ConclusionsUS-CT fusion-image-guided RFA improved tumor visibility scores and overall mean technical validity and resulted in a comparable disease-free survival rate to LPN.

Pretargeting articulation for improving the deliverance of injected dose to the tumor: An evaluation of In vivo study for enhanced tumor uptake

Background: Radiobioconjugate targeting using monoclonal antibodies linked to a high-energy radionuclide is a promising approach for treating metastatic cancer. The central problem of radiobioconjugate targeting is the small fraction of radiobioconjugate localized in the tumor. Pretargeting based on avidin–biotin approach has been recommended to maximize tumor targeting. The current study was conceded with an aim to assess a selective targeting strategy for the site-specific deliverance of an injected radioactive dose to the tumor cells. Methods: Two labeling protocols were tested and evaluated, both for the direct and indirect radiolabeling of antibodies with radionuclide technetium. A comparative evaluation of biodistribution studies relating to the deposition of injected dose in different organs was carried out in tumor-bearing nude mice both for a direct single-step and indirect multistep pretargeting approach. Results: High concentration of the injected dose was accounted in the nontarget organs and blood for a direct targeting mode, as compared to indirect multistep pretargeting with high tumor uptake. Better tumor visibility and high tumor/nontumor ratio were observed at 24 h and 48 h. However, a considerable deposition of radioactivity in the organs such as liver, spleen, kidney, and lungs as a nonspecific, reticuloendothelial system uptake was observed as a cause of concern and the use of certain blocking agents were explored, effective for reducing the same. Conclusions: The study demonstrates a successful targeting efficiency of the radiolabeled bioconjugate for technetium (Tc-99m), through a multistep pretargeting approach, and the same can be applied for other related therapy radionuclides also.

Diffusion-weighted imaging of breast invasive lobular carcinoma: comparison with invasive carcinoma of no special type using a histogram analysis.

To investigate the imaging findings and visibility of breast invasive lobular carcinoma (ILC) on diffusion-weighted imaging (DWI) and compare quantitative apparent diffusion coefficient (ADC) metrics of ILC and invasive carcinoma of no special type (NST) using a histogram analysis. We performed an observational retrospective study of 629 consecutive women with pathologically proven ILC and invasive ductal carcinoma of NST, who underwent 3-T MRI including DWI, between January 2017 and August 2020. After propensity score matching, 71 women were allocated to each group. On DWI, 9 (12.7%) lesions of ILC and 4 (5.6%) invasive carcinomas of the NST were not visualized. For the tumor visibility on DWI, tumor size, tumor ADC value, and background diffusion grade were significantly associated with the visibility score in both groups (all P<0.05), whereas the mean background ADC value was not significant (P>0.05). The mean ADC (1.226×10-3 vs. 1.052×10-3 mm2/s, P<0.001), median ADC (1.222×10-3 vs. 1.051×10-3 mm2/s, P=0.002), maximum ADC (1.758×10-3 vs. 1.504×10-3 mm2/s, P<0.001), minimum ADC (0.717×10-3 vs. 0.649×10-3 mm2/s, P=0.003), 90th percentile ADC (1.506×10-3 vs. 1.292×10-3 mm2/s, P<0.001) and 10th percentile ADC (0.956×10-3 vs. 0.818×10-3 mm2/s, P=0.008) were higher in ILC than in invasive carcinoma of NST. Additionally, the ADC difference value of the ILC was higher than that of invasive carcinoma of NST (1.04×10-3 vs. 0.855×10-3 mm2/s, P=0.027). On DWI, the visibility of ILC was lower compared to invasive carcinoma of NST. ILC showed higher quantitative ADC values and higher ADC difference values.

Water Cycle Bat Algorithm and Dictionary-Based Deformable Model for Lung Tumor Segmentation.

Among the different types of cancers, lung cancer is one of the widespread diseases which causes the highest number of deaths every year. The early detection of lung cancer is very essential for increasing the survival rate in patients. Although computed tomography (CT) is the preferred choice for lungs imaging, sometimes CT images may produce less tumor visibility regions and unconstructive rates in tumor portions. Hence, the development of an efficient segmentation technique is necessary. In this paper, water cycle bat algorithm- (WCBA-) based deformable model approach is proposed for lung tumor segmentation. In the preprocessing stage, a median filter is used to remove the noise from the input image and to segment the lung lobe regions, and Bayesian fuzzy clustering is applied. In the proposed method, deformable model is modified by the dictionary-based algorithm to segment the lung tumor accurately. In the dictionary-based algorithm, the update equation is modified by the proposed WCBA and is designed by integrating water cycle algorithm (WCA) and bat algorithm (BA).

Transarterial Chemoembolization with LC Bead LUMI followed by Stereotactic Body Radiation Therapy in Treatment of Hepatocellular Carcinoma

PurposeTransarterial chemoembolization (TACE) in combination with stereotactic body radiation therapy (SBRT) is a promising therapy for patients with hepatocellular carcinoma (HCC). A radiopaque drug-eluting embolic bead used during TACE, called LC Bead LUMI (Boston Scientific), was developed to allow improved visualization during TACE. The purpose of this case series is to assess the visibility of LUMI after TACE and discuss its potential use as an alignment tool for SBRT. MethodsFourteen patients with HCC (median age 69) received TACE using LUMI immediately followed by SBRT to 50 Gy in 5 fractions (13 patients) or 40 Gy in 5 fractions (1). Computed tomography (CT) simulation and cone beam CT (CBCT) images taken before each fraction were compared with immediate post-TACE imaging. Success of the LUMI bead opacification was graded from excellent to poor visualization. Patients were followed to assess target lesion response, disease control, survival, and the long-term visibility of LUMI beads. ResultsCBCT immediately after TACE with LUMI displayed excellent tumor visibility for 6 of 13 patients (46.2%), moderate tumor visibility for 4 patients (30.8%), and poor tumor visibility for 3 patients (23.1%). When comparing CBCTs used for SBRT image verification to post-TACE CBCT, 53.8% remained unchanged and 46.2% deteriorated from excellent to moderate or moderate to poor, but none deteriorated from excellent to poor visualization. Median follow-up was 13 months (range 2-35). On average, LUMI beads were visible on noncontrast CT up to 20 months after SBRT. ConclusionsLC Bead LUMI has the ability to provide liver tumor demarcation on noncontrast and cone beam CT weeks to months following TACE. It can serve as an alignment tool and could improve the therapeutic ratio in liver SBRT by allowing for tumor margin reduction with a potential decrease in the risk of toxicity when treating HCC in facilities without magnetic resonance imaging-linear accelerator.

Usefulness of ultrasound fusion technology for hepatocellular carcinoma localisation, pre- and post-thermal ablation.

Percutaneous thermal ablation of inconspicuous lesions can be challenging. Fusion ultrasound (FUS) allows the use of previously performed diagnostic imaging like computed tomography (CT), magnetic resonance imaging (MRI) and positron emission tomography (PET-CT) to localise hepatocellular carcinoma (HCC) for treatment. This paper illustrates FUS case studies of pre-, intra- and post-ablation imaging of inconspicuous HCC, supplemented by use of contrast-enhanced ultrasound (CEUS). Four prospective cases during September 2014 to October 2018, with HCC amenable to ablation, which were poorly identified on ultrasound, underwent FUS. FUS pre-screening was scheduled within three months of the previous CT or MRI, and between one to four weeks prior to the scheduled ablation date. Post-ablation imaging with FUS was performed between four to six weeks to coincide with their routine follow-up CT or MRI. There were potential benefits observed in the cases with combined techniques of FUS and CEUS for limiting circumstances such as heat sink effect, multiple lesions targeting, inconspicuous lesion detection and pre-ablation technical feasibility assessment. The combined use of FUS and CEUS improves tumour visibility, increases operator imaging confidence and reduces heat sink effect during percutaneous thermal ablation. FUS imaging is helpful in targeting poor conspicuity lesions that cannot be detected on grey-scale ultrasound. It facilitates in ensuring optimal treatment of hepatic lesions for improvement of patient prognosis and follow-up imaging.

Second window ICG predicts gross-total resection and progression-free survival during brain metastasis surgery.

Metastases are the most common intracranial malignancies and complete resection can provide relief of neurological symptoms and reduce recurrence. The authors' prospective pilot study in 2017 demonstrated promising results for the application of high-dose, delayed imaging of indocyanine green (ICG), known as second window ICG (SWIG), in patients undergoing surgery for brain metastases. In this prospective cohort study, the authors evaluated intraoperative imaging and clinical outcomes of treatment using SWIG. Patients were prospectively enrolled in an approved study of high-dose, delayed ICG (SWIG) and received 5 mg/kg (2014-2018) or 2.5 mg/kg (2018-2019) ICG 24 hours preoperatively. Intraoperatively, near-infrared (NIR) imaging was performed using a dedicated NIR exoscope. NIR images were analyzed and the signal-to-background ratio (SBR) was calculated to quantify fluorescence. Residual fluorescence on the postresection NIR view was compared and correlated to the residual gadolinium enhancement on postoperative MRI. Patient survival and predictive factors were analyzed. In total, 51 intracranial metastases were surgically treated in 47 patients in this cohort. All 51 metastatic tumors demonstrated strong NIR fluorescence (mean SBR 4.9). In tumors ≤ 10 mm from the cortical surface, SWIG with 5 mg/kg ICG produced enhanced transdural tumor visibility (91.3%) compared to 2.5 mg/kg (52.9%; p = 0.0047). Neoplastic margin detection using NIR fluorescence compared to white light improved sensitivity, albeit lowered specificity; however, increasing the SBR cutoff for positive fluorescence significantly improved specificity without sacrificing sensitivity, increasing the overall accuracy from 57.5% to 72.5%. A lack of residual NIR fluorescence after resection was closely correlated with a lack of residual enhancement on postoperative MRI (p = 0.007). Among the 16 patients in whom tumor recurred at the site of surgery, postoperative MRI successfully predicted 8 cases, whereas the postresection NIR view predicted 12 cases. Progression-free survival rate at 12 months was greater for patients without residual NIR fluorescence (38%) than for those without residual enhancement on postoperative MRI (29%). The current study demonstrates the clinical benefits of the SWIG technique in surgery for patients with brain metastases. Specifically, this technique allows for dose-dependent, transdural localization of neoplasms and improved sensitivity in neoplastic margin detection. Postresection residual fluorescence can be a powerful tool to evaluate extent of resection in conjunction with MRI, and it may guide decisions on brain metastasis management.

A novel approach for radiotherapy dose escalation in rectal cancer using online MR-guidance and rectal ultrasound gel filling – Rationale and first in human

IntroductionDose escalated radiotherapy has previously been investigated as a strategy to increase complete response rates in rectal cancer. However large safety margins are required using cone-beam computed tomography guided radiotherapy leading to high doses to organs at risk or insufficient target volume coverage in order to keep dose constraints. We herein present the first clinical application of a new technique for dose escalation in rectal cancer using online magnetic resonance (MR)-guidance and rectal ultrasound gel filling. MethodsA 73-year-old patient with distal cT3a cN0 cM0 rectal cancer was referred for definitive radiochemotherapy with the goal of organ preservation after multidisciplinary discussion. A dose of 45 Gy in 25 fractions with a stereotactic integrated boost to the primary tumor of 50 Gy with concomitant 5-fluorouracil was prescribed. Furthermore, a boost to the primary tumor with 3 Gy per fraction using the adapt-to-shape workflow on a 1.5 T MR-Linac was planned once weekly. For the boost fractions 100 cc of ultrasound gel was applied rectally in order to improve tumor visibility and distancing of uninvolved rectal mucosa. In order to determine the required planning target volume margin diagnostic scans of ten rectal cancer patients conducted with rectal ultrasound gel filling were studied. ResultsBased on the ten diagnostic scans an average isotropic margin of 4 mm was found to be sufficient to cover 95% of the target volume during an online adaptive workflow. Three boost fractions were applied, mean treatment duration was 22:34 min. Treatment was well tolerated by the patient with no more than PRO-CTCAE grade I° toxicity of any kind. The rectal ultrasound gel filling resulted in superior visibility of the tumor and reduced the dose to the involved mucosa especially in the high dose range compared with a boost plan calculated without any filling. A considerable tumor shrinkage was observed during treatment from 17.43 cc at baseline to 4 cc in week four. ConclusionThis novel method appears to be a simple but effective strategy for dose escalated radiotherapy in rectal cancer. Based on the encouraging observation, a prospective trial is currently under preparation.

Effective Strain Image Sequence Selection by Using Semi-Automated Image Processing Technique

One fourth of the cancer detected in women worldwide is breast cancer which leads this as a major threat for women. There are many methods of detecting cancer among which ultra-sound strain imaging is one of the promising techniques. However, in strain sequence, not all the frames show clear tumor visibility. Consequently, in this paper we tested some well-defined algorithms to find only those frames where the tumor is comparatively clearly visible. We have used Mean Pixel Difference (MPD) and Gray- Level Co-occurrence Matrix (GLCM) to find the frames with better tumor visibility. We have tested our methods in several real-life cases and the results have been examined by a professional doctor. The MPD has an accuracy of 96.2% and the GLCM. Contrast has that of 55.55%.&#x0D; GUB JOURNAL OF SCIENCE AND ENGINEERING, Vol 7, Dec 2020 P 8-13

Percutaneous radiofrequency ablation for hepatic metastasis of colorectal cancer: assessment of tumor visibility and the feasibility of the procedure with planning ultrasonography.

PurposeThe aim of this study was to assess the incidence and causes of percutaneous radiofrequency ablation (RFA) infeasibility in cases of metastatic colorectal cancer and to evaluate factors affecting the invisibility of the tumor on planning ultrasonography (US).MethodsThis study screened 386 patients who underwent planning US using fusion imaging and/or contrast-enhanced US for percutaneous RFA for suspected metastatic colorectal cancer between January 2013 and December 2020, from whom 136 patients with a single hepatic metastasis from colorectal cancer measuring <3 cm were included. The factors related to the infeasibility of percutaneous RFA were investigated. Univariate and multivariate analyses were performed to assess the factors associated with tumor invisibility on planning US.ResultsAmong the 136 patients, percutaneous RFA was considered infeasible in 24.3% (33/136) due to a high risk of the heat-sink effect caused by the abutment of a large vessel (n=12), an inconspicuous tumor on planning US (n=11), a high risk of collateral thermal damage to an adjacent organ (n=8), and the absence of a safe electrode path (n=2). In univariate and multivariate analyses, tumor size was a statistically significant factor affecting invisibility on planning US (P=0.003 and P=0.018, respectively).ConclusionPercutaneous RFA was infeasible in approximately one-fourth of patients with metastatic colorectal cancer. The reason for the infeasibility was mainly an unfavorable tumor location and invisibility on planning US. Small tumor size was the sole significant factor affecting the invisibility of hepatic metastases on planning US.

Validation of a 4D-MRI guided liver stereotactic body radiation therapy strategy for implementation on the MR-linac

Purpose. Accurate tumor localization for image-guided liver stereotactic body radiation therapy (SBRT) is challenging due to respiratory motion and poor tumor visibility on conventional x-ray based images. Novel integrated MRI and radiotherapy systems enable direct in-room tumor visualization, potentially increasing treatment accuracy. As these systems currently do not provide a 4D image-guided radiotherapy strategy, we developed a 4D-MRI guided liver SBRT workflow and validated all steps for implementation on the Unity MR-linac. Materials and Methods. The proposed workflow consists of five steps: (1) acquisition of a daily 4D-MRI scan, (2) 4D-MRI to mid-position planning-CT rigid tumor registration, (3) calculation of daily tumor midP misalignment, (4) plan adaptation using adapt-to-position (ATP) with segment-weights optimization and (5) adapted plan delivery. The workflow was first validated in a motion phantom, performing regular motion at different baselines (±5 to ±10 mm) and patient-derived respiratory signals with varying degrees of irregularity. 4D-MRI derived respiratory signals and 4D-MRI to planning CT registrations were compared to the phantom input, and gamma and dose-area-histogram analyses were performed on the delivered dose distributions on film. Additionally, 4D-MRI to CT registration performance was evaluated in patient images using the full-circle method (transitivity analysis). Plan adaption was further analyzed in-silico by creating adapted treatment plans for 15 patients with oligometastatic liver disease. Results. Phantom trajectories could be reliably extracted from 4D-MRI scans and 4D-MRI to CT registration showed submillimeter accuracy. The DAH-analysis demonstrated excellent coverage of the dose evaluation structures GTV and GTVTD. The median daily rigid 4D-MRI to midP-CT registration precision in patient images was <2 mm. The ATP strategy restored the target dose without increased exposure to the OARs and plan quality was independent from 3D shift distance in the range of 1–26 mm. Conclusions. The proposed 4D-MRI guided strategy showed excellent performance in all workflow tests in preparation of the clinical introduction on the Unity MR-linac.

Simultaneous multi-slice accelerated 4D-MRI for radiotherapy guidance

4D-MRI is becoming increasingly important for daily guidance of thoracic and abdominal radiotherapy. This study exploits the simultaneous multi-slice (SMS) technique to accelerate the acquisition of a balanced turbo field echo (bTFE) and a turbo spin echo (TSE) coronal 4D-MRI sequence performed on 1.5 T MRI scanners. SMS single-shot bTFE and TSE sequences were developed to acquire a stack of 52 coronal 2D images over 30 dynamics. Simultaneously excited slices were separated by half the field of view. Slices intersecting with the liver-lung interface were used as navigator slices. For each navigator slice location, an end-exhale dynamic was automatically identified, and used to derive the self-sorting signal by rigidly registering the remaining dynamics. Navigator slices were sorted into 10 amplitude bins, and the temporal relationship of simultaneously excited slices was used to generate sorted 4D-MRIs for 12 healthy volunteers. The self-sorting signal was validated using an in vivo peak-to-peak motion analysis. The smoothness of the liver-lung interface was quantified by comparing to sagittal cine images acquired directly after the SMS-4D-MRI sequence. To ensure compatibility with the MR-linac radiotherapy workflow, the 4D-MRIs were transformed into 3D mid-position (MidP) images using deformable image registration. Consistency of the deformable vector fields was quantified in terms of the distance discordance metric (DDM) in the body. The SMS-4D-TSE sequence was additionally acquired for 3 lung cancer patients to investigate tumor visibility. SMS-4D-MRI acquisition and processing took approximately 7 min. 4D-MRI reconstruction was possible for 26 out of 27 acquired datasets. Missing data in the sorted 4D-MRIs varied from 4%–26% for the volunteers and varied from 8%–24% for the patients. Peak-to-peak (SD) amplitudes analysis agreed within 1.8 (1.1) mm and 0.9 (0.4) mm between the sorted 4D-MRIs and the self-sorting signals of the volunteers and patients, respectively. Liver-lung interface smoothness was found to be in the range of 0.6–3.1 mm for volunteers. The percentage of DDM values smaller than 2 mm was in the range of 85%–89% and 86%–92% for the volunteers and patients, respectively. Lung tumors were clearly visibility in the SMS-4D-TSE images and MidP images. Two fast SMS-accelerated 4D-MRI sequences were developed resulting in T2/T1 or T2 weighted contrast. The SMS-4D-MRIs and derived 3D MidP-MRIs yielded anatomically plausible images and good tumor visibility. SMS-4D-MRI is therefore a strong candidate to be used for treatment simulation and daily guidance of thoracic and abdominal MR-guided radiotherapy.