نتائج البحث - "Hounsfield scale"

71

Investigating the impact of the CT Hounsfield unit range on radiomic feature stability using dual energy CT data

المؤلفون: Avishek Chatterjee, Martin Vallières, Jan Seuntjens, Reza Forghani

المساهمون: RS: GROW - R3 - Innovative Cancer Diagnostics & Therapy, Precision Medicine

المصدر: Physica Medica: European journal of medical physics, 88, 272-277. ELSEVIER SCI LTD

الوصف: Purpose Radiomic texture calculation requires discretizing image intensities within the region-of-interest. FBN (fixed-bin-number), FBS (fixed-bin-size) and FBN and FBS with intensity equalization (FBNequal, FBSequal) are four discretization approaches. A crucial choice is the voxel intensity (Hounsfield units, or HU) binning range. We assessed the effect of this choice on radiomic features. Methods The dataset comprised 95 patients with head-and-neck squamous-cell-carcinoma. Dual energy CT data was reconstructed at 21 electron energies (40, 45,… 140 keV). Each of 94 texture features were calculated with 64 extraction parameters. All features were calculated five times: original choice, left shift (-10/-20 HU), right shift (+10/+20 HU). For each feature, Spearman correlation between nominal and four variants were calculated to determine feature stability. This was done for six texture feature types (GLCM, GLRLM, GLSZM, GLDZM, NGTDM, and NGLDM) separately. This analysis was repeated for the four binning algorithms. Effect of feature instability on predictive ability was studied for lymphadenopathy as endpoint. Results FBN and FBNequal algorithms showed good stability (correlation values consistently > 0.9). For FBS and FBSequal algorithms, while median values exceeded 0.9, the 95% lower bound decreased as a function of energy, with poor performance over the entire spectrum. FBNequal was the most stable algorithm, and FBS the least. Conclusions We believe this is the first multi-energy systematic study of the impact of CT HU range used during intensity discretization for radiomic feature extraction. Future analyses should account for this source of uncertainty when evaluating the robustness of their radiomic signature.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::e0043dc5f0b3f949a2d25fbfbc664b26Test
https://doi.org/10.1016/j.ejmp.2021.07.023Test

72

Radiologic Findings of Complicated Alloplastic Implants in the Nasal Dorsum

المؤلفون: Kim, Sung Hee, Kim, Ji Won, Jang, Yong Ju

المصدر: Clinical and Experimental Otorhinolaryngology
Clinical and Experimental Otorhinolaryngology, Vol 14, Iss 3, Pp 321-327 (2021)

الوصف: Objectives When performing cosmetic rhinoplasty with alloplastic materials, complications such as implant visualization, inflammation, dislocation, and extrusion should be thoroughly evaluated. Although computed tomography (CT) can give us useful information about the implant status and its interaction with the skin soft tissue envelop (SSTE), radiologic findings of these interactions have rarely been reported. Methods We retrospectively reviewed the data of eighty patients who underwent facial bone CT or ostiomeatal unit (OMU) CT at the Asan Medical Center between July 2008 and January 2020 for the evaluation of complicated dorsal implants. We reviewed the implantation period, implant dislocation, implant curling or deformation, Hounsfield unit (HU), and nasal bone changes including bone erosion or hyperostosis. Results Of the 80 patients, 67 (83.8%) patients had silicone implants and 13 (16.2%) patients had Gore-Tex implants. The radiologic findings of the silicone implants were as follows: maintained implant shape (80.6%), radiolucent (similar density to that of fat tissue) halo (83.6%), homogenous attenuation (82.1%). Peri-implant calcification was often found in silicone implants with >20-year implantation periods. Those of Gore-Tex were as follows; curling or deformation (84.6%), heterogeneous attenuation (84.6%), and in terms of peri-implant calcification, there was no tendency of change over time. Conclusion The silicone and Gore-Tex implants have distinctive radiologic features. These findings of alloplastic materials help us to know how the implant behaves in the nasal dorsum and how it affects the SSTE.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::724c20a28ef6c3d0f2919af67a0f8dd5Test
https://doi.org/10.21053/ceo.2020.01725Test

73

Is there a difference in the outcomes of anterior cervical discectomy and fusion among female patients with different menopausal statuses?

المؤلفون: Xin Rong, Ying Hong, Wang Xingjin, Beiyu Wang, Yang Meng, Junbo He, Hao Liu, Chen Ding, Yi Yang, Quan Gong

المصدر: Journal of Orthopaedic Surgery and Research, Vol 16, Iss 1, Pp 1-10 (2021)
Journal of Orthopaedic Surgery and Research

الوصف: Background The surgical outcomes of anterior cervical discectomy and fusion (ACDF) in female patients according to menopausal status remain unclear. The objective of this study was to investigate the differences in these outcomes among female patients with different menopausal statuses. Methods Ninety-one patients undergoing single-level or consecutive two-level ACDF with a minimum 12-month postoperative follow-up were included in this study. There were 38 patients in the premenopausal group, 28 patients in the early postmenopausal group, and 25 patients in the late postmenopausal group. The clinical outcomes were evaluated by means of the neck disability index (NDI) scores, Japanese Orthopedic Association (JOA) scores, and visual analog scale (VAS) scores. Radiological parameters included cervical lordosis (CL), the functional spinal unit (FSU) angle, range of motion (ROM) of the total cervical spine, ROM of the FSU, anterior and posterior FSU height, implant subsidence, adjacent segment degeneration (ASD), and Hounsfield unit (HU) values. Results All groups showed significant improvements in their JOA, VAS, and NDI scores (P < 0.05). The differences in preoperative and final follow-up CL, ROM of C2-7, FSU angle, and ROM of FSU were not statistically significant among the three groups (P > 0.05). The anterior FSU height loss rate showed a significant difference (P = 0.043), while there was no difference in the posterior FSU height loss rate (P = 0.072). The fusion rates in the early and late postmenopausal groups were consistently lower than those in the premenopausal group during the follow-up period. All patients had satisfactory outcomes at the final follow-up. Conclusion There were no significant differences in clinical or other related outcomes of single-level or consecutive two-level ACDF in the long term among female patients with different menopausal statuses. However, the early bony fusion rates and anterior FSU height loss rates were poorer in late postmenopausal patients than in premenopausal or early postmenopausal patients. Hence, importance should be attached to the protection of late postmenopausal patients in the early postoperative period to guarantee solid bony fusion.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::711195e05e43e542162ade96608001a3Test
https://doaj.org/article/ebb662a73d354c0a933a1e3039719fbaTest

74

Mediation effects of mean Hounsfield unit on relationship between hemoglobin and expansion of intracerebral hemorrhage

المؤلفون: Moon Ku Han, Han-Gil Jeong, Chang Wan Oh, Jihoon Kang, Jun Yup Kim, Tackeun Kim, Hee-Joon Bae, Jae Seung Bang, Yong Soo Kim, Hee Yun Chae, Beom Joon Kim

المصدر: Scientific Reports, Vol 11, Iss 1, Pp 1-8 (2021)
Scientific Reports

الوصف: Low hemoglobin levels are known to be associated with hematoma expansion (HE) and poor functional outcome in patients with intracerebral hemorrhage (ICH). However, it is not yet known whether low hemoglobin itself causes HE directly or is merely a confounder. Thus, we investigated the mediation effect of the mean Hounsfield unit (HU) of hematoma on the relationship between low hemoglobin and expansion of ICH. Overall, 232 consecutive patients with ICH who underwent non-contrast computed tomography (NCCT) within 12 h since onset were included. The mean HU and hematoma volume on NCCT were investigated using semi-automated planimetry. HE was defined as an increase in hematoma volume > 33% or 6 mL. The respective associations among the hemoglobin level, mean HU, and HE were analyzed using multivariable regression analysis, adjusting for age, sex, and known HE predictors. Mediation analysis was performed to examine the potential causal association among the three. HE occurred in 34.5% of patients; hemoglobin levels were inversely associated with HE occurrence (adjusted odds ratio, 0.90; p = 0.03). The mean HU of the hematoma was lower in patients with HE than in patients without HE (58.5 ± 3.3 vs. 56.8 ± 3.0; p p p = 0.04). The proportion of indirect effect through the mean HU among the total effect was 19% (p = 0.05). The mediation effect became nonsignificant in the when the multivariable model was adjusted with additional covariates (baseline systolic blood pressure and hematoma location). The mean HU of the hematoma mediated the association between hemoglobin levels and HE occurrence. Therefore, the mean HU of the hematoma may be a potential marker of impaired hemostasis in patients with ICH.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::c1724161dac9c906f31890bc81b9cdc0Test
https://doaj.org/article/525a65f8b31e494e81a3b51bd33dca18Test

75

Are Hounsfield Unit Measurements of Bony Absorption Changes in Cholesteatoma Helpful?

المؤلفون: Sharon Tamir, Tal Marom, Oded Kraus, Judith Luckman, Shay Shemesh

المصدر: International Archives of Otorhinolaryngology v.26 n.3 2022
International Archives of Otorhinolaryngology
Fundação Otorrinolaringologia (FORL)
instacron:FORL
International Archives of Otorhinolaryngology, Volume: 26, Issue: 3, Pages: 414-421, Published: 04 NOV 2022
International Archives of Otorhinolaryngology (2021)

الوصف: Introduction High-resolution computed tomography (HRCT) scans of the temporal bone are used to assess the bony erosion of the middle-ear structures whenever cholesteatoma is suspected. Objective To study the differences in HRCT Hounsfield unit (HU) index measurements of middle-ear bony structures between an ears with and without cholesteatoma. Methods A retrospective study of 59 patients who underwent surgery due to unilateral cholesteatoma. The HRCT HU index of the scutum, of three middle-ear ossicles, of the lateral semicircular canal (LSCC), and of the fallopian canal was measured in both ears. A comparison was made between the cholesteatoma and the non-cholesteatomatous ear (control). All measurements were conducted by an otolaryngologist. To assess the interobserver bias, 10% of the samples were randomly and independently assessed by another otolaryngologist and a neuroradiologist who were blinded. Results The average HU index was lower in the ear with cholesteatoma when compared with the non-cholesteatomatous ear. While the differences were statistically significant regarding the measurements of the scutum (516.02 ± 311.693 versus 855.64 ± 389.999; p = 0.001), the malleus (1049.44 ± 481.765 versus 1413.47 ± 313.376; p = 0.01), and the incus (498.03 ± 264.184 versus 714.25 ± 405.631; p = 0.001), the differences in the measurements of the LSCC (1042.34 ± 301.066 versus 1154.53 ± 359.609; p = 0.69) and of the fallopian canal (467.19 ± 221.556 versus 543.51 ± 263.573; p = 0.108) were not significantly different between both groups. The stapes was immeasurable in both groups due to its small size. Conclusion Hounsfield unit index measurements are a useful tool that may aid in the diagnosis of early-stage cholesteatoma.

وصف الملف: text/html

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::983a5f0dd63ba3b846551b1a8e389257Test
http://old.scielo.br/scielo.php?script=sci_arttext&pid=S1809-48642022000300414Test

76

Determination of Tumor Size and Hounsfield Unit/Electron Density Values in Three Different CT Scans for Lung SBRT Planning

المؤلفون: Ayse Okumus

المصدر: International Journal of Hematology and Oncology. 31:192-198

مصطلحات موضوعية: Electron density, Lung, medicine.anatomical_structure, Oncology, Tumor size, business.industry, Hounsfield scale, medicine, Hematology, business, Nuclear medicine

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_________::deda55b4060dd1de62164ed784d49596Test
https://doi.org/10.4999/uhod.214054Test

77

CT-based thermometry with virtual monoenergetic images by dual-energy of fat, muscle and bone using FBP, iterative and deep learning–based reconstruction

المؤلفون: U Teichgräber, A Heinrich, Sebastian Schenkl, David Buckreus, Felix V. Güttler

المصدر: European Radiology

الوصف: Objectives The aim of this study was to evaluate the sensitivity of CT-based thermometry for clinical applications regarding a three-component tissue phantom of fat, muscle and bone. Virtual monoenergetic images (VMI) by dual-energy measurements and conventional polychromatic 120-kVp images with modern reconstruction algorithms adaptive statistical iterative reconstruction-Volume (ASIR-V) and deep learning image reconstruction (DLIR) were compared. Methods A temperature-regulating water circuit system was developed for the systematic evaluation of the correlation between temperature and Hounsfield units (HU). The measurements were performed on a Revolution CT with gemstone spectral imaging technology (GSI). Complementary measurements were performed without GSI (voltage 120 kVp, current 130–545 mA). The measured object was a tissue equivalent phantom in a temperature range of 18 to 50°C. The evaluation was carried out for VMI at 40 to 140 keV and polychromatic 120-kVp images. Results The regression analysis showed a significant inverse linear dependency between temperature and average HU regardless of ASIR-V and DLIR. VMI show a higher temperature sensitivity compared to polychromatic images. The temperature sensitivities were 1.25 HU/°C (120 kVp) and 1.35 HU/°C (VMI at 140 keV) for fat, 0.38 HU/°C (120 kVp) and 0.47 HU/°C (VMI at 40 keV) for muscle and 1.15 HU/°C (120 kVp) and 3.58 HU/°C (VMI at 50 keV) for bone. Conclusions Dual-energy with VMI enables a higher temperature sensitivity for fat, muscle and bone. The reconstruction with ASIR-V and DLIR has no significant influence on CT-based thermometry, which opens up the potential of drastic dose reductions. Key Points • Virtual monoenergetic images (VMI) enable a higher temperature sensitivity for fat (8%), muscle (24%) and bone (211%) compared to conventional polychromatic 120-kVp images. • With VMI, there are parameters, e.g. monoenergy and reconstruction kernel, to modulate the temperature sensitivity. In contrast, there are no parameters to influence the temperature sensitivity for conventional polychromatic 120-kVp images. • The application of adaptive statistical iterative reconstruction-Volume (ASIR-V) and deep learning–based image reconstruction (DLIR) has no effect on CT-based thermometry, opening up the potential of drastic dose reductions in clinical applications.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::694d3f7b57c65956710a93a853ab1414Test
https://doi.org/10.1007/s00330-021-08206-zTest

78

Diversity of lymphatic flow in patients with lung cancer revealed by computed tomography lymphography

المؤلفون: Naoya Kawakita, Hiroaki Toba, Yukikiyo Kawakami, Kazuya Kondo, Hiromitsu Takizawa, Mitsuteru Yoshida, Akira Tangoku

المصدر: Interact Cardiovasc Thorac Surg

الوصف: OBJECTIVES This study was conducted to verify the optimal extent of lymph node dissection or sampling during lung cancer surgery based on the sentinel node (SN) map created by computed tomography (CT) lymphography. METHODS From April 2010 to January 2015, patients with clinical stage I non-small-cell lung cancer, who were candidates for lobectomy or segmentectomy with standard hilar and mediastinal lymph node dissection, and in whom bronchus reached the tumour, were enrolled. An ultrathin bronchoscope was inserted to the target bronchus under the guidance of virtual bronchoscopic navigation images. CT images of the chest were obtained 30 s after 2.5 ml of iopamidol was injected. SNs were identified when the maximum CT attenuation value of the lymph nodes on postcontrast CT images increased by 30 Hounsfield units or more compared with the precontrast images. Patients underwent lobectomy with standard lymph node dissection. RESULTS SNs were identified in 36 (87.8%) of the 41 patients. The average number of SNs was 1.6 (range, 1–4). There was 1 false negative case; therefore, the accuracy of SN identification was 97.2% (35/36). In 5 (13.9%) of 36 patients, SNs were outside the lobe-specific lymph node station range (#11i from right S1, #7 from right S1, #4R from right S8, #12u from right S8, #7 and #12l from left S1 + 2). CONCLUSIONS CT lymphography demonstrated the diversity of lymphatic spreading patterns and there were cases in which lymph flows are found outside the lymph node dissection range.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::6ed617ab258f04ae58a451f6c924d54cTest
https://doi.org/10.1093/icvts/ivab204Test

79

Characteristics of surgically transposed ovaries on 18F-FDG PET/CT among patients with cancer

المؤلفون: So-Young Kim, Kwan Hyeong Jo, Won Jun Kang, Sang Hyun Hwang, Yong Hyu Jeong, Eun Ji Nam

المصدر: Annals of Nuclear Medicine. 35:1100-1108

مصطلحات موضوعية: medicine.medical_specialty, business.industry, Cancer, Soft tissue, Ovary, General Medicine, medicine.disease, Metastasis, Ovarian transposition, medicine.anatomical_structure, Hounsfield scale, Medicine, Endocrine system, Radiology, Nuclear Medicine and imaging, Fertility preservation, Radiology, business

الوصف: Fertility preservation in women with cancer is important for improving their quality of life. Successful ovarian transposition protects the ovary from radiation and preserves ovarian endocrine function and fertility. With the increasing use of 18F-FDG PET/CT in gynecologic malignancies, the findings of transposed ovaries sometimes vary. This study aimed to characterize the 18F-FDG PET/CT findings of surgically transposed ovaries among a large number of patients with various medical conditions. We retrospectively reviewed the medical records, including surgical history, and analyzed the findings of the transposed ovaries of patients who underwent ovarian transposition. Quantitative analysis was performed, and the maximum standardized uptake values (SUVs) were recorded. The Hounsfield unit (HU) and size (measured using the long diameter on the axial image) of the transposed ovary were evaluated. No significant change was found in the SUV of the transposed ovaries in relation to age and time after surgery. In two cases in which metastasis occurred in the transposed ovary, the lesions showed higher SUVs and HUs than did the other non-metastatic transposed ovaries. In several serial follow-up cases, varying 18F-FDG uptake was observed. The 18F-FDG uptake pattern of the transposed ovary did not differ from that of the normal ovary. Misinterpretation should be avoided by considering surgical records, presence of surgical clips, and patients’ disease state. If there is a high uptake in the transposed ovary, it is necessary to check for soft tissue lesions and differentiate metastasis from the physiologic uptake.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_________::34dd73a00ec596375b5da6796f969a3eTest
https://doi.org/10.1007/s12149-021-01645-0Test

80

Assessment of the impact of CT calibration procedures for proton therapy planning on pediatric treatments

المؤلفون: Esther Bär, A. Warry, Ying Zhang, Charles-Antoine Collins-Fekete, V. Rompokos, A. Poynter, Gary Royle, Mark N. Gaze

المصدر: Medical Physics. 48:5202-5218

مصطلحات موضوعية: Male, Phantoms, Imaging, business.industry, Infant, Newborn, Planning target volume, Soft tissue, General Medicine, medicine.disease, Pediatrics, Imaging phantom, Hounsfield scale, Calibration, Proton Therapy, Humans, Medicine, Female, Sarcoma, Child, Tomography, X-Ray Computed, Head and neck, Nuclear medicine, business, Proton therapy

الوصف: PURPOSE Relative stopping powers (RSPs) for proton therapy are estimated using single-energy computed tomography (SECT), calibrated with standardized tissues of the adult male. It is assumed that those tissues are representative of tissues of all age and sex. Female, male, and pediatric tissues differ from one another in density and composition. In this study, we use tabulated pediatric tissues and computational phantoms to investigate the impact of this assumption on pediatric proton therapy. The potential of dual-energy CT (DECT) to improve the accuracy of these calculations is explored. METHODS We study 51 human body tissues, categorized into male/female for the age groups newborn, 1-, 5-, 10-, and 15-year-old children, and adult, with given compositions and densities. CT numbers are simulated and RSPs are estimated using SECT and DECT methods. Estimated tissue RSPs from each method are compared to theoretical RSPs. The dose and range errors of each approach are evaluated on three computational phantoms (Ewing's sarcoma, salivary sarcoma, and glioma) derived from pediatric proton therapy patients. RESULTS With SECT, soft tissues have mean estimation errors and standard deviation up to (1.96 ± 4.18)% observed in newborns, compared to (0.20 ± 1.15)% in adult males. Mean estimation errors for bones are up to (-3.35 ± 4.76)% in pediatrics as opposed to (0.10 ± 0.66)% in adult males. With DECT, mean errors reduce to (0.17 ± 0.13)% and (0.23 ± 0.22)% in newborns (soft tissues/bones). With SECT, dose errors in a Ewing's sarcoma phantom are exceeding 5 Gy (10% of prescribed dose) at the distal end of the treatment field, with volumes of dose errors >5 Gy of Vdiff>5=4630.7 mm3 . Similar observations are made in the head and neck phantoms, with overdoses to healthy tissue exceeding 2 Gy (4%). A systematic Bragg peak shift resulting in either over- or underdosage of healthy tissues and target volumes depending on the crossed tissues RSP prediction errors is observed. Water equivalent range errors of single beams are between -1.53 and 5.50 mm (min, max) (Ewing's sarcoma phantom), -0.78 and 3.62 mm (salivary sarcoma phantom), and -0.43 and 1.41 mm (glioma phantom). DECT can reduce dose errors to

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::ce43b33e9aaceb87d2fc0086f087bd06Test
https://doi.org/10.1002/mp.15062Test

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