Hounsfield Unit Ratio Research Articles

Lymphadenopathy Secondary to Metastatic Squamous Cell Carcinoma Mistaken for Malignant Lymphoma.

It is difficult to identify disease entities underlying lymphadenopathy in the head and neck region based solely on imaging. This often results in metastatic squamous cell carcinoma (Sqcc)-induced lymphadenopathy being mistaken for lymphoma. This study aimed to analyze clinical characteristics and computed tomographic features that aid in distinguishing between metastatic Sqcc and lymphoma when lymphadenopathy resembles a large solitary lymphoma. The authors retrospectively enrolled 5 patients, managed between 2010 and 2024, with metastatic Sqcc mistaken for lymphoma and 9 patients with lymphadenopathy of 2cm or larger due to lymphoma. Among the 5 patients, 3 exhibited a homogeneous lymphadenopathy phenotype, whereas the remaining 2 displayed heterogeneous enhancement with multiple small necrotic areas within the affected masses. Measurement of the Hounsfield units (HU) for lymphadenopathy, the sternocleidomastoid muscle, and the submandibular gland (SMG) was conducted for each patient. The ratio of lymphadenopathy HU to the average HU of the sternocleidomastoid muscle and the SMG was significantly higher in patients diagnosed with metastatic Sqcc compared with those with lymphoma (P = 0.01). In computed tomography scans, heterogeneous lymphadenopathy or enhancement levels that approach or exceed those of the SMG may indicate the likelihood of Sqcc rather than lymphoma.

6613 Liver and Spleen Linked in Hepatic Steatosis during Weight Reduction in Type 2 Diabetes

Abstract Disclosure: K. Han: None. K. Min: None. Splenectomy increased serum lipids, except triglyceride (TG) and high-density lipoprotein (HDL), significantly accelerating hepatic steatosis in animal study. Recently, the concept of a liver-spleen axis has been proposed in nonalcoholic fatty liver disease. The purpose of this study was to investigate change of the liver Hounsfield Units (HU), reflecting the hepatic steatosis, and its relation to spleen HU, central, or peripheral and ectopic adipose tissue during weight reduction in type 2 diabetes. Total 187 women with type 2 diabetes were educated on lifestyle modification. We assessed liver Hounsfield Units(HU) and spleen HU with total abdominal fat(ATAF) , visceral adipose tissue (AVAT), subcutaneous adipose tissue(ASAT) at mid-abdomen level, and total adipose tissue (TTAT)and intramuscular adipose tissue(TIMAT) at midthigh level using nonenhanced computed tomography, at baseline and 12 weeks. We investigated whether changes in liver HD were related to fat in other regions, serum triglycerides, free fatty acids, and adiponectin-leptin ratio (ALR). The participants’ age was 55.2±7.3 years, BMI was 27.3±2.7 kg/m2, Body Weight (BW) 66.8±6.9kg). Baseline liver HU was 54.7±11.5, and spleen HU was 48.5±8.5. At 12 weeks, BW lost 2.4±2.2kg. Liver HU changed with spleen HU (r=0.357, p<0.001, ATAT(r=-0.343, p<0.0001), AVAT (r=0.220, p=.011), ASAT(r=-0.339, p<0.001) and adiponectin-leptin ratio (ALR) (r=-0.174, p=0.047), but no significant relations with TTAT, TIMAT, triglyceride, and free fatty acid. Linear regression analysis showed the best model for change of liver HU (Model R2=0.209, p<0.001) was as follows: Change of Liver HU=0.534 +0.038* change of spleen HU - 0.290* change of ATAF. Higher spleen HU (p<0.001) and lower abdominal fat (p<0.001) predicted higher liver HU (less steatosis). These results suggested that the liver might be metabolically linked to the spleen in hepatic steatosis of type 2 Diabetes. Presentation: 6/2/2024

Diagnostic Value of Hounsfield Units for Osteoporotic Thoracolumbar Vertebral Non-Compression Fractures in Elderly Patients with Low-Energy Injuries.

Thoracolumbar vertebral fractures are common pathological fractures caused by osteoporosis in the elderly. These fractures are challenging to detect. This study aimed to evaluate the diagnostic value of Hounsfield units for osteoporotic thoracolumbar vertebral non-compression fractures in elderly patients with low-energy fractures. The retrospective case-control study included elderly patients diagnosed with osteoporotic thoracolumbar vertebral fractures and non-fractured patients who underwent computed tomography examinations for lumbar vertebra issues during July 2017 and June 2020. This study included 216 patients with fractures (38 males and 178 females; average age: 77.28±8.68 years) and 124 patients without fractures (21 males and 103 females; average age: 75.35±9.57 years). The difference in Hounsfield units of the target (intermediate) vertebral body significantly differed between the two groups (54.74 ± 21.84 vs 5.86 ± 5.14; p<0.001). The ratios of Hounsfield units were also significantly different between the two groups (1.38 ± 1.60 vs 0.13 ± 0.23; p<0.001). The cut-off value for the difference in Hounsfield units to detect osteoporotic spine fractures was 25.35, with high sensitivity (98.5%), specificity (99.9%), and the area under the curve (AUC) (0.999, 95% CI: 0.999-1). The cut-off value for the odds ratio of Hounsfield units was 0.260, with high sensitivity (99.1%), specificity (92.7%), and AUC (0.970, 95% CI: 0.949-0.992). The difference between Hounsfield units and the odds ratio of Hounsfield units might help diagnose osteoporotic thoracolumbar vertebral non-compression fractures in elderly patients with low-energy fractures.

Abstract PO4-02-05: Elevated tumor to aorta ratio of Hounsfield units and late recurrence in patients with estrogen receptor positive breast cancer

Abstract Background) More than half of the recurrent disease in breast cancer will happen more than 5 years after initial diagnosis in breast cancer, especially in patients with ER positive disease. Higher proportions of late recurrence lead to escalated treatment and/or or extended treatment for high risk patients. However, it is unclear what characteristics make whom as high risk patients. This study aimed to assess initial tumor vascularity as a prognostic marker for late recurrence. Methods) Female patients with estrogen receptor positive breast cancer who were diagnosed breast cancer between 2003 and 2018 and disease-free at 5 years after primary breast cancer at Wonju Severance Hospital, Korea, were included. Clinocopathological characteristics were collected. Hounsfield units(HU) on contrast-enhanced computed tomography(CT) was used as a marker indicating tumor vascularity. Tumor to aortic arch ratio(TAR) of HU on contrast enhanced CT was applied to enhance objectivity of measurement. Patients were categorized according to the cut-off values retrieved from the receiver operating characteristic curve. Kaplan-Meier curves were generated to compare recurrence-free survival (RFS) and overall survival (OS). Hazard ratio(HR) with confidence interval(CI) was derived with Cox’s proportional hazard model to analyze univariate and multivariate risk factors. Results) The final cohort included 451 patients with a mean age of 56.21 ± 11.2 (22-83) years. Two third of patients had estrogen receptor positive disease and a quarter of patients had HER2 overexpressed disease. Initial TAR was 0.345 ± 0.108 (range, 0.062 - 1.114). Patients with recurrence free survival(RFS)-related events had significantly higher TAR than patients who did not(0.39 ± 0.097 vs. 0.34 ± 0.108, p=0.012). Patients with overall survival(OS)-related events also had higher TAR than patients who did not(0.408 ± 0.096 vs. 0.342 ± 0.107, p=0.002). Cutoff value of 0.408 was driven from area under the receiver operating characteristic curve. Patients with TAR higher than 0.408 showed significantly worse RFS(p=0.001) and OS(p&amp;lt; 0.001) than patients who had TAR equal or lower than 0.408. Hazard ratio(HR) of TAR in late recurrence was 6.17 (CI, 4.89 – 9.23, p=0.003), suggesting it is an independent factor. Other independent factors were age (HR, 1.502; CI, 10.14 – 10.91; p=0.006), tumor size (HR, 1.268; CI, 1.071 – 1.502; p=0.006), and metastatic nodal disease (HR, 2.770; CI, 1.176 – 6.526; p=0.020). Conclusion) TAR of primary tumor was significantly related with patients RFS and OS. Patients with high TAR larger than 0.408 showed worse RFS and OS than patients who did not. According to the Cox proportional hazard model, TAR was an independent factor along with age, tumor size, and metastatic nodal disease, suggesting late recurrence may rather be influenced by clinical factor Citation Format: Airi Han, Hyang Suk Choi, Seok Hahn, In-jeoung Cho, Seung Taek Lim, Jong-In Lee. Elevated tumor to aorta ratio of Hounsfield units and late recurrence in patients with estrogen receptor positive breast cancer [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO4-02-05.

The Relationship Between Calcaneofibular Ligament Injury and Ankle Osteoarthritis Progression: A Comprehensive Analysis of Stress Distribution and Osteophyte Formation in the Subtalar Joint.

Ankle osteoarthritis (OA) mainly arises from trauma, particularly lateral ligament injuries. Among lateral ligament injuries, ankles with calcaneofibular ligament (CFL) injuries exhibit increased instability and can be a risk factor ankle OA progression. However, the relationship between CFL injury and OA progression remains unclear. Therefore, this study aims to assess the relationship between CFL injuries and ankle OA by investigating stress changes and osteophyte formation in subtalar joint. We retrospectively reviewed the magnetic resonance imaging (MRI) and plain radiographic evaluations of 100 ankles of 91 patients presenting with chronic ankle instability (CAI), ankle OA, or other ankle conditions. The association between CFL injuries on the oblique view of MRI and the severity of ankle OA (based on Takakura-Tanaka classification) was statistically evaluated. Additionally, 71 ankles were further subjected to CT evaluation to determine the association between the CFL injuries and the Hounsfield unit (HU) ratios of the subtalar joint and medial gutter, and the correlation between the subtalar HU ratios and osteophyte severity were statistically evaluated. CFL injury was observed in 35.9% (14/39) of patients with stage 0, 42.9% (9/21) with stage 1, 50.0% (10/20) with stage 2, 100% (9/9) with stage 3a, and 90.9% (10/11) with stage 3b. CFL-injured ankles exhibited higher HU ratios in the medial gutter and lower ratios in the medial posterior subtalar joint compared to uninjured ankles. A negative correlation was observed between medial osteophyte severity and the medial subtalar joint HU ratio. Our findings suggest that CFL injuries are common in severe ankle OA impairing the compensatory function of the subtalar joint through abnormal stress distribution and osteophyte formation.

Renal calculus composition analysis using dual-energy CT: a prospective observational study

BackgroundTo analyze preoperatively the composition of renal calculi using dual-energy computed tomography (DECT) and compare it with reference standard biochemical stone analysis.MethodsEighty-one participants who were diagnosed with renal calculi underwent DECT at 80 kVp and 140 kVp. Spectral analysis was performed, and the energy map generated was used to classify the calculus based on available preset data. Average Hounsfield units (HU) were calculated for the two energy levels, and ratio of HU was derived (DE ratio) and calculus was categorized into different stone compositions. Hounsfield units of each calculus was measured at 120 kVp standard dose CT, and Hounsfield density (HU/largest transverse diameter) was derived. Comparison of results of spectral analysis and DE ratio was done and correlated with the biochemical laboratory analysis as reference standard wherever available.ResultsSpectral analysis and CT prediction of stone were performed for all 81 patients. CT prediction of stone based on DE ratio into “uric acid,” “struvite,” “calcium oxalate” and “calcium carbonate apatite” was performed. Assessment of stone composition by biochemical analysis was done for 65 patients who eventually underwent PCNL for stone extraction.Both DE ratio and spectral analysis were able to differentiate calculus into various types based on composition with statistically significant p values. However, spectral analysis proved to be marginally better in renal stone characterization particularly for mixed stones. The DE ratio for uric acid stones was derived as 0.9–1.1, 0.9–2.3 for mixed stones and 1.0–2.4 for calcium stones.ConclusionsSpectral analysis promises a practical approach to predicting calculus composition preoperatively, thereby avoiding unnecessary surgical intervention.

Predictive Value of Dual-Energy CT-Derived Metrics for the Use of Bone Substitutes in Distal Radius Fracture Surgery.

(1) Background: Low bone mineral density (BMD) is a significant risk factor for complicated surgery and leads to the increased use of bone substitutes in patients with distal radius fractures (DRFs). No accepted model has yet been established to predict the use of bone substitutes to facilitate preoperative planning. (2) Methods: Unenhanced dual-energy CT (DECT) images of DRFs were retrospectively acquired between March 2016 and September 2020 using the internal PACS system. Available follow-up imaging and medical health records were reviewed to determine the use of bone substitutes. DECT-based BMD, trabecular Hounsfield units (HU), cortical HU, and cortical thickness ratio were measured in non-fractured segments of the distal radius. Diagnostic accuracy parameters were calculated for all metrics using receiver-operating characteristic (ROC) curves and associations of all metrics with the use of bone substitutes were evaluated using logistic regression models. (3) The final study population comprised 262 patients (median age 55 years [IQR 43-67 years]; 159 females, 103 males). According to logistic regression analysis, DECT-based BMD was the only metric significantly associated with the use of bone substitutes (odds ratio 0.96, p = 0.003). However, no significant associations were found for cortical HU (p = 0.06), trabecular HU (p = 0.33), or cortical thickness ratio (p = 0.21). ROC-curve analysis revealed that a combined model of all four metrics had the highest diagnostic accuracy with an area under the curve (AUC) of 0.76. (4) Conclusions: DECT-based BMD measurements performed better than HU-based measurements and cortical thickness ratio. The diagnostic performance of all four metrics combined was superior to that of the individual parameters.

Relationship between pain and intra-articular pathology in patients with chronic lateral ankle instability.

Repeated ankle sprains can lead to chronic lateral ankle instability (CLAI). It is unclear whether CLAI causes pain unless complicated by intra-articular lesions. This study aimed to analyze the characteristics of pain and the relationship between pain and intra-articular pathology in patients with CLAI. Fifty-three ankles in 46 patients with CLAI who had undergone surgery were retrospectively reviewed. The self-administered foot evaluation questionnaire (SAFE-Q) was given to patients the day before surgery. Intra-articular lesions were assessed using arthroscopy and magnetic resonance imaging (MRI). In addition, the Hounsfield Unit (HU) on computed tomography (CT) of the medial gutter was measured. The relationship between pain and intra-articular findings was also analyzed. The pain and pain-related scores in the SAFE-Q were significantly correlated with synovitis in 96.3% (rs = - 0.532). HU ratios in the tibia and talus were also significantly correlated with pain (rs = - 0.603, - 0.534, respectively). The arthroscopic synovitis score and HU ratios in patients with high pain scores were significantly higher than those in patients with low pain scores. Forty ankles (75.5%) had synovitis and articular cartilage injuries were observed in 22 ankles (41.5%). Patients with fluid collection or bone marrow lesions (BML) scored significantly lower in pain than those without, but there was no significant difference between patients with and without cartilage injury. Multiple regression analysis revealed that a high synovitis score and HU ratio of the talus were significantly associated with high pain. Intra-articular lesions such as synovitis and BML were associated with pain in patients with CLAI. Osteosclerotic changes in the medial gutter also induced ankle pain, indicating that osteoarthritic changes had already begun. Therefore, lateral ankle ligament injuries after ankle sprain should be appropriately treated to avoid secondary degenerative changes.

Abstract 17083: Aortic Luminal Contrast Attenuation Varies With Dissection Morphology and is Associated With Need For Intervention

Introduction: Prognostication after acute Type B aortic dissection (aTBAD) may be limited when relying upon static computed tomographic angiography (CTA) images to evaluate a dynamic process. We performed an exploratory study to characterize variations in luminal contrast attenuation on CTA, as a surrogate for blood flow in dissection, and to determine whether the resulting parameters held prognostic value. Methods: Retrospective, single-institution data for patients with aTBAD were gathered from 1999-2020. Patients with prior dissection repairs were excluded. Dissection morphology was classified by the SVS/STS scheme and location/number of fenestrations. Hounsfield unit ratios (HUR) comparing lumina, phases, and aortic zone were calculated. Aortic growth, false lumen thrombosis, and need for intervention were evaluated with univariable logistic regression. Results: After exclusions, 85 patients were identified (mean age 61.9 years, 69.4% male). SVS/STS B 3,10 (20%) and B 3,5 (12.9%) predominated (Figure). Most fenestrations were in Zone 4/5 (56.5%) and associated with more equilibrated HUR (0.93) compared to dissections without fenestration (0.70, p = 0.04). Fenestration zone was not associated with HUR ( p = 0.59). Intervention occurred in 65.9%, most often for aneurysmal degeneration (43.8%), followed by visceral/limb ischemia (32.6%). Growth occurred in 28.2%. Increased arterial false-to-true HUR was strongly associated with eventual need for intervention (OR 25.3 [95% CI 4.15-188.4], p = 0.001) while increased delayed-to-arterial false lumen HUR was associated with decreased intervention (OR 0.49 [95% CI 0.25-0.89], p = 0.02). Conclusion: In patients with aTBAD, calculated permutations of HUR across lumina and between CTA phases may give insight into blood flow dynamics, which in turn likely impact need for intervention. Future prospective studies of time-resolved CTA are likely to hold significant prognostic value and alter management.

OR25-06 The Effect of Testosterone Replacement Therapy on NAFLD in Elderly Hypogonadal Men

Abstract Disclosure: H. Lee: None. S. Han: None. R.S. Swerdloff: None. Y. Pak: None. M.J. Budoff: None. C.C. Wang: None. The Effect of Testosterone Replacement Therapy on NAFLD in Elderly Hypogonadal Men Background: Aging increases body weight, visceral fat, insulin resistance and metabolic syndrome, leading to increased prevalence of nonalcoholic fatty liver disease(NAFLD) in elderly. Testosterone deficiency, more prevalent in elderly men, is associated with metabolic syndrome and increased visceral fat. The T Trials evaluated the effect of testosterone treatment on sexual function, physical function, and vitality. A substudy on the effect of testosterone on cardiovascular markers showed decrease in total cholesterol, LDL cholesterol, HDL cholesterol, fasting insulin level and HOMA-IR in testosterone treatment group compared to placebo. We hypothesized that testosterone replacement in elderly male with hypogonadism will improve NAFLD. Methods: Data from the T Trial was used to evaluate prevalence of NAFLD using 3 clinical scores in testosterone treatment group and placebo group; Lipid accumulation product (LAP) index, hepatic steatosis index (HSI) and NAFLD-MS score. A randomized sub-group of the placebo and testosterone treated subjects had cardiac CT (Computed tomography) that includes liver and spleen. Liver Hounsfield unit (HU) and spleen HU were obtained to evaluate NAFLD by CT criteria. Clinical liver fat scores and CT findings were evaluated at baseline and 12 months post treatment. Correlation between each liver fat score (LAP index, HSI and NAFLD-MS score) and liver CT findings were analyzed. Results: 502 male of age 65 and over with total testosterone &amp;lt;275ng/dL were analyzed (testosterone group n= 246, placebo group n=233). Baseline testosterone levels were not different between the two groups at baseline. Testosterone level was increased by 285.5±266.4ng/dL in the treatment group compared to 1.98±73.6ng/dL in the placebo group (p= 0.0001). Prevalence of NAFLD in elderly hypogonadal men by LAP index, HSI and NAFLD-MS were 89.77%, 88.93% and 3.96% respectively. 30% of subjects had liver HU&amp;lt;40, 21.36% had liver-to-spleen HU ratio (LSR)&amp;lt;1. There were no statistically significant changes in liver fat scores and CT findings in each arm at baseline and after 12 months treatment. Subgroup analysis on subjects with NAFLD defined by LAP index, liver HU or LSR did not show improvement of NAFLD after 12 months of testosterone replacement. Among the 3 liver fat scores, only LAP index showed inverse correlation with liver HU. Conclusion: Our study did not show improvement of NAFLD in elderly hypogonadal male after 12 months of testosterone replacement compared to placebo, assessed by lipid accumulation product index, hepatic steatosis index, NAFLD-MS score, liver HU and liver-to-spleen ratio. Future studies with longer treatment duration and additional modalities to define NAFLD as primary outcome may be warranted. Presentation Date: Saturday, June 17, 2023

Nonenhanced Computed Tomography Evaluation Of Ischemic Stroke Patients Presenting After 4.5 Hours From Onset Of Symptoms Using Aspects, Posterior Circulation-Aspects And X-Ray Attenuation Ratio: The “Tissue Window”

Background: Stroke is a major cause of disability and mortality world-wide. Ischemic stroke is reversible when patients present early. With the current treatment guideline in Nigeria, most ischemic stroke patients present after the 4.5 hours treatment “time window” and are ineligible for intravenous thrombolysis (IVT). However, studies with computed tomography and magnetic resonance imaging have shown variability in the duration of tissue viability, with some remaining viable up to 24 hours and beyond. These advanced imaging are not readily available in the sub-Saharan Africa but the X-ray attenuation ratio of hypoattenuating lesions on the easily accessible nonenhanced computed tomography (NECT), have recently shown to be a valuable alternative. In late presentation, IVT and endovascular thrombectomy (EVT) have proven to have reasonable degree of success in recanalization. Hence, the need for the study.&#x0D; Materials and method: This was a retrospective cross-sectional study of ischemic stroke patients who presented between 4.5 and 24 hours for NECT. The extent of the ischemia was determined using the Alberta stroke programme early CT score (ASPECTS), while the Hounsfield unit ratio of the hypodense lesions was used to determine tissue viability.&#x0D; Results: Fifty-five patients met the inclusion criteria and had a mean age of 58.8 years. Four (7.27%) patients clearly had ASPECTS and Hounsfield unit ratio (HUr) scores suggestive of salvageable penumbral tissue, while another four (7.27%) had the probability of being reversible.&#x0D; Conclusion: Some patients were still eligible for treatment after the current guideline’s 4.5 hours treatment “time window” using the ASPECTS and HUr scores on NECT.&#x0D; &#x0D;

A customized anthropomorphic 3D-printed phantom to reproducibility assessment in computed tomography: an oncological case study.

Studies on computed tomography (CT) reproducibility at different acquisition parameters have to take into account radiation dose administered and related ethical issues. 3D-printed phantoms provide the possibility to investigate these features deeply and to foster CT research, also taking advantage by outperforming new generation scanners. The aim of this study is to propose a new anthropomorphic 3D-printed phantom for chest lesions, tailored on a real patient CT scan, to investigate the variability of volume and Hounsfield Unit (HU) measurements at different CT acquisition parameters. The chest CT of a 75-year-old patient with a paramediastinal lung lesion was segmented based on an eight-compartment approach related to HU ranges (air lung, lung interstitium, fat, muscle, vascular, skin, bone, and lesion). From each mask produced, the 3D.stl model was exported and linked to a different printing infill value, based on a preliminary test and HU ratios derived from the patient scan. Fused deposition modeling (FDM) technology printing was chosen with filament materials in polylactic acid (PLA). Phantom was acquired at 50 mAs and three different tube voltages of 80, 100, and 120 kVp on two different scanners, namely, Siemens Somatom Force (Siemens Healthineers, Erlangen, Germany; same setting of real patient for 80 kVp acquisition) and GE 750 HD CT (GE Healthcare, Chicago, IL). The same segmentation workflow was then applied on each phantom acquisition after coregistration pipeline, and Dice Similarity Coefficient (DSC) and HU averages were extracted and compared for each compartment. DSC comparison among real patient versus phantom scans at different kVp, and on both CT scanners, demonstrated a good overlap of different compartments and lesion vascularization with a higher similarity for lung and lesion masks for each setting (about 0.9 and 0.8, respectively). Although mean HU was not comparable with real data, due to the PLA material, the proportion of intensity values for each compartment remains respected. The proposed approach demonstrated the reliability of 3D-printed technology for personalized approaches in CT research, opening to the application of the same workflow to other oncological fields.

Hounsfield Units Predict Survival of Patients With Estrogen Receptor-Positive and Human Epithelial Growth Factor Receptor 2-Negative Breast Cancer

BackgroundsTumor vascularity plays a fundamental role in cancer progression, including breast cancer. This study aimed to elucidate tumor vascularity and its impact on patient survival in the context of breast cancer subtypes using Hounsfield units (HU) on contrast-enhanced computed tomography (CT). Materials and methodsPatients with early-stage breast cancer who completed planned treatment between 2003 and 2013 were retrospectively assessed. ResultsThe final cohort comprised 440 patients. Of the 440 patients, 262 had estrogen receptor (ER)-positive disease and 119 had human epidermal growth factor receptor 2 (HER2)-overexpressing disease. The tumor-to-aorta ratio of Hounsfield units (TAR) was related to significantly worse recurrence-free interval (RFI) (P < .001) and overall survival (OS) (P < .001) in patients with TAR > 0.33 for RFI and > 0.35 for OS than their counterparts. In the subgroup analysis, the survival disadvantage was limited only to patients with ER-positive and HER2-negative disease (P < .001 for both RFI and OS). ConclusionThis study showed that TAR, which reflects tumor vascularity, was significantly related to patients’ RFI and OS, suggesting its capacity as a feasible biomarker. This study also showed that TAR was associated with the survival in patients with ER-positive and HER2-negative disease.

Abstract P2-11-30: Performance of tumor vascularity as a biomarker is correlated with the change of tumor vascularity after preoperative systemic treatment in patients with breast cancer

Abstract Background) Breast cancer is a leading cause of death worldwide. Tumor vascularity is a hallmark of cancer including breast cancer. However, targeting tumor vascularity did not show consistent benefit when applied in clinic. This study aimed to investigate in which group of patients can tumor vascularity be a prognostic factor and how does change of tumor vascularity play in this situation. Materials and methods) Female patients with breast cancer who received preoperative chemotherapy due to breast cancer between 2003 and 2018 at Wonju Severance Hospital, Korea, were included. Clinocopathological characteristics were collected. Hounsfield units(HU) on contrast-enhanced computed tomography(CT) was used as a marker indicating tumor vascularity. Tumor to aortic arch ratio(TAR) of HU on contrast enhanced CT was applied to enhance objectivity of measurement. Patients were categorized according to the cut-off values retrieved from the receiver operating characteristic curve. Kaplan-Meier curves were generated to compare recurrence-free interval (RFI) and overall survival (OS). Results) The final cohort included 162 patients with a mean age of 48.63±7.9 (30-69) years. Initial TAR was 0.38±0.103 (range, 0.184-0.946) and TAR after completion of preoperative systemic treatment was 0.29 0.094(0.677-0.298). Difference between TAR of immediate before surgery and first clinical presentation was -0.0860.094(-0.386 – 0.176). TAR was decreased in 122 (75.3%) patients. Initial TAR was significantly correlated with recurrence free survival(RFS)(p=0.002). However, TAR after preoperative systemic treatment (p=0.221) or delta TAR (area under receiver operating characteristics = 0.498) were not significant. Interestingly, initial TAR was significant only in patients with decreased TAR after preoperative systemic treatment(p=0.005). Conclusion) Tumor vascularity represented with HU was significantly related with patients’ survival only when tumor vascularity was decreased in response to systemic treatment. Considering no antiangiogenic agents were applied as preoperative systemic treatment and still capacity of tumor vascularity as a biomarker was influenced by the change of itself, antiangiogenic agents could be used as a complimentary agent for the other agents which also impact tumor vascularity. Citation Format: Hyang Suk Choi, Eun Ju Son, Hany Hany Noh, In-Jeong Cho In-Jeong Cho, Seung Taek Lim, Jong-In Lee, Airi Han. Performance of tumor vascularity as a biomarker is correlated with the change of tumor vascularity after preoperative systemic treatment in patients with breast cancer. [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P2-11-30.

Deep learning-based automatic left atrial appendage filling defects assessment on cardiac computed tomography for clinical and subclinical atrial fibrillation patients

Rationale and objectivesSelecting region of interest (ROI) for left atrial appendage (LAA) filling defects assessment can be time consuming and prone to subjectivity. This study aimed to develop and validate a novel artificial intelligence (AI), deep learning (DL) based framework for automatic filling defects assessment on CT images for clinical and subclinical atrial fibrillation (AF) patients. Materials and methodsA total of 443,053 CT images were used for DL model development and testing. Images were analyzed by the AI framework and expert cardiologists/radiologists. The LAA segmentation performance was evaluated using Dice coefficient. The agreement between manual and automatic LAA ROI selections was evaluated using intraclass correlation coefficient (ICC) analysis. Receiver operating characteristic (ROC) curve analysis was used to assess filling defects based on the computed LAA to ascending aorta Hounsfield unit (HU) ratios. ResultsA total of 210 patients (Group 1: subclinical AF, n = 105; Group 2: clinical AF with stroke, n = 35; Group 3: AF for catheter ablation, n = 70) were enrolled. The LAA volume segmentation achieved 0.931–0.945 Dice scores. The LAA ROI selection demonstrated excellent agreement (ICC ≥0.895, p < 0.001) with manual selection on the test sets. The automatic framework achieved an excellent AUC score of 0.979 in filling defects assessment. The ROC-derived optimal HU ratio threshold for filling defects detection was 0.561. ConclusionThe novel AI-based framework could accurately segment the LAA region and select ROIs while effectively avoiding trabeculae for filling defects assessment, achieving close-to-expert performance. This technique may help preemptively detect the potential thromboembolic risk for AF patients.

Comparison of different quantitative evaluation protocols for peri-device leak detection using cardiac computed tomography angiography after left atrial appendage closure

This study seeks to propose and compare different quantitative evaluation methods for identifying patients with peri-device leak (PDL) using cardiac computed tomography angiography (CCTA). Patients who had undergone left atrial appendage (LAA) closure and both transesophageal echocardiography (TEE) and CCTA were enrolled. Hounsfield units (HU) were measured in the proximal and distal regions of the left atrial appendage (p-LAA, d-LAA) on the CCTA, and the average of the two was determined (a-LAA). The relative HU ratios of the LAA to the center of the left atrium (LA) were calculated (p-LAA/c-LA, d-LAA/c-LA, a-LAA/c-LA). The area under the curve (AUC) for the LAA HU and the LAA/LA HU ratio were analyzed and compared. Fifty-one patients were included in this study. Pairwise comparisons showed a statistically significant difference (p = 0.029) in diagnostic performance between the d-LAA (AUC = 0.868) and a-LAA (AUC = 0.972). There were no significant differences between the a-LAA and p-LAA (p = 0.549) or between the d-LAA and p-LAA (p = 0.053). At the optimal cutoff for a-LAA of 115.5 HU, the sensitivity was 100%, the specificity was 88%. At the optimal cutoff for p-LAA of 109 HU, the sensitivity was 100%, the specificity was 84%. The LAA/LA HU ratio did not exhibit better diagnostic performance than HU attenuation in the LAA (p > 0.05). The a-LAA > 115.5 is useful in identifying PDL. Due to its convenience and intuitiveness, p-LAA > 109.0 can also be used as an alternative protocol for a-LAA.

Distribution of Bone Mineral Density in the Ankle Joint: Correlation with Hindfoot Alignment

Category: Ankle; Basic Sciences/Biologics; Hindfoot Introduction/Purpose: Abnormal Hindfoot Alignment (HA) has been correlated with increased complication rates in ankle fusion or replacement. Altered Bone Mineral Density (BMD) due to abnormal stress distribution could be predisposing factor for those unwanted outcomes. The objective of this study was to assess spatial distribution of BMD around the ankle joint in patients with normal or abnormal HA using cone beam Weight Bearing CT. Methods: Retrospective comparative study including 81 ankles allocated into 3 groups based on the Foot Ankle Offset (FAO): 27 normal (0%5%). groups were comparable by age (p=0.967), Body Mass Idex (p=0.669), sex (p=0.820) and side (p=0.708). Semi- automatic segmentation (BoneLogic, Disior) was applied to identify bones. Tibia and talus were digitally compartmented in medial (M) and lateral (L) volumes relative to the median sagittal plane. Mean Hounsfield Unit (HU) value per compartment was used to assess BMD and to calculate the Medial over Lateral HU ratio (M/L-HU). Comparisons among the three groups were performed using one-way ANOVA, Kruskal-Wallis and Chi2 tests. Results: Mean +- standard deviation HU values in the compartments in normal cases were 495.2+-110 (medial tibia), 495.6+- 108.1 (lateral tibia), 368.9+-80.3 (medial talus), 448.2+-90.6 (lateral talus) and 686.7+-120.4 (fibula). Upon comparison of the mean BMD value for each compartment in the three groups, the difference did not achieve statistical significance. Conversely, the tibia HU-M/L ratio (0.88+-0.14 in valgus cases, 0.99 +- 0.08 in normally-aligned cases and 1.04+-0.08 in varus cases) and the talar HU- M/L ratio (0.68+-0.18 in valgus cases, 0.82+-0.08 in normally-aligned cases and 0.96+-0.20 in varus cases) were significantly different in the three groups (p&lt;0.001). Conclusion: We found that the BMD in distal tibia, fibula and the talus varies with hindfoot alignment. The increased HU medio- lateral ratio in varus cases was consistent with a greater medial bone density in the tibia and talus, while the decreased ratio found in valgus cases suggested a more lateral concentration in both bones. This data supports the role of WBCT in analyzing BMD distribution. This method could be clinically useful in ankle OA to evaluate bone quality for such considerations as surgical indications or implant positioning.

Functional biomarkers derived from computed tomography and magnetic resonance imaging differentiate PDAC subgroups and reveal gemcitabine-induced hypo-vascularization

PurposePancreatic ductal adenocarcinoma (PDAC) is a molecularly heterogeneous tumor entity with no clinically established imaging biomarkers. We hypothesize that tumor morphology and physiology, including vascularity and perfusion, show variations that can be detected by differences in contrast agent (CA) accumulation measured non-invasively. This work seeks to establish imaging biomarkers for tumor stratification and therapy response monitoring in PDAC, based on this hypothesis.Methods and materialsRegional CA accumulation in PDAC was correlated with tumor vascularization, stroma content, and tumor cellularity in murine and human subjects. Changes in CA distribution in response to gemcitabine (GEM) were monitored longitudinally with computed tomography (CT) Hounsfield Units ratio (HUr) of tumor to the aorta or with magnetic resonance imaging (MRI) ΔR1 area under the curve at 60 s tumor-to-muscle ratio (AUC60r). Tissue analyses were performed on co-registered samples, including endothelial cell proliferation and cisplatin tissue deposition as a surrogate of chemotherapy delivery.ResultsTumor cell poor, stroma-rich regions exhibited high CA accumulation both in human (meanHUr 0.64 vs. 0.34, p < 0.001) and mouse PDAC (meanAUC60r 2.0 vs. 1.1, p < 0.001). Compared to the baseline, in vivo CA accumulation decreased specifically in response to GEM treatment in a subset of human (HUr −18%) and mouse (AUC60r −36%) tumors. Ex vivo analyses of mPDAC showed reduced cisplatin delivery (GEM: 0.92 ± 0.5 mg/g, vs. vehicle: 3.1 ± 1.5 mg/g, p = 0.004) and diminished endothelial cell proliferation (GEM: 22.3% vs. vehicle: 30.9%, p = 0.002) upon GEM administration.ConclusionIn PDAC, CA accumulation, which is related to tumor vascularization and perfusion, inversely correlates with tumor cellularity. The standard of care GEM treatment results in decreased CA accumulation, which impedes drug delivery. Further investigation is warranted into potentially detrimental effects of GEM in combinatorial therapy regimens.

Detection of left atrial appendage thrombus by dual-energy computed tomography-derived imaging biomarkers in patients with atrial fibrillation.

AimsThis study aimed to assess the diagnostic performances of dual-energy computed tomography (CT)-derived iodine concentration and effective atomic number (Zeff) in early-phase cardiac CT in detecting left atrial appendage (LAA) thrombus and differentiating thrombus from spontaneous echo contrast (SEC) in patients with atrial fibrillation using transesophageal echocardiography (TEE) as the reference standard.Methods and resultsA total of 389 patients with atrial fibrillation were prospectively recruited. All patients underwent a single-phase cardiac dual-energy CT scan using a third-generation dual-source CT. The iodine concentration, Zeff, and conventional Hounsfield units (HU) in the LAA were measured and normalized to the ascending aorta (AA) of the same slice to calculate the LAA/AA ratio. Of the 389 patients, TEE showed thrombus in 15 (3.9%), SEC in 33 (8.5%), and no abnormality in 341 (87.7%) patients. Using TEE findings as the reference standard, the respective sensitivity, specificity, positive predictive value, and negative predictive value of the LAA/AA HU ratio for detecting LAA thrombus were 100.0, 96.8, 55.6, and 100.0%; those of the LAA/AA iodine concentration ratio were 100.0, 99.2, 83.3, and 100.0%; and those of the LAA/AA Zeff ratio were 100.0, 98.9, 79.0, and 100.0%. The areas under the receiver operator characteristic curve (AUC) of the LAA/AA iodine concentration ratio (0.978; 95% CI 0.945–1.000) and Zeff ratio (0.962; 95% CI 0.913–1.000) were significantly larger than that of the LAA/AA HU ratio (0.828; 95% CI 0.714–0.942) in differentiating the thrombus from the SEC (both P < 0.05). Although the AUC of the LAA/AA iodine concentration ratio was larger than that of the LAA/AA Zeff ratio, no significant difference was found between them (P = 0.259).ConclusionThe dual-energy CT-derived iodine concentration and the Zeff showed better diagnostic performance than the conventional HU in early-phase cardiac CT in detecting LAA thrombus and differentiating the thrombus from the circulatory stasis. However, these results need to be validated in large-cohort studies with late-phase images.

CT review of ovarian fibrothecoma.

The aim of this study was to investigate the CT imaging characteristics of ovarian fibrothecoma which may aid in the differentiation from early stage epithelial tumours. Comparison of 36 patients (41 lesions) with pathologically proven ovarian fibrothecoma tumours and 36 (52 lesions) serous papillary carcinomas (SPCs) lesions. We noted their laterality, size, density, calcifications, Hounsfield units (HUs) and introduced a novel HU comparison technique with the psoas muscle or the uterus. Patients' clinical findings such as ascites, pleural effusion, carbohydrate antigen-125 levels, and lymphadenopathy findings were also included. Average age was 67.8 and 66 across the fibrothecoma and SPC cohort respectively. Fibrothecoma tumours had diameters ranging from 24 to 207 mm (Median: 94 mm). 80.6% of the fibrothecoma cohort had ascites which was comparable to the 72.2% in the SPC cohort. 70.7% of fibrothecoma tumour favour a purely to predominantly solid structural configuration (p < 0.001). The average HU value for the fibrothecoma solid component was 44 ± 11.7 contrasting the SPC HU value of 66.8 ± 15. The psoas:tumour mass ratio demonstrated a median of 0.7, whereas SPCs shows a median of 1.1 (p < 0.001). Suspicion of ovarian fibrothecoma should be considered through interrogation of their structural density configuration, low psoas to mass HU ratio and a presence of ascites. CT imaging can be a useful tool in diagnosing fibrothecoma tumours and subsequently reducing oncogynaecological tertiary centre referrals, financial burden and patient operative morbidity and mortality.