Search Results (81)

Objective: This study aimed to evaluate whether modifying the post-processing algorithm of Twin-Spiral Dual-Energy computed tomography (DECT) improves infarct detection compared to conventional Dual-Energy CT (DECT) and Single-Energy CT (SECT) following endovascular therapy (EVT) for large vessel occlusion (LVO). Methods: We retrospectively analyzed 52 patients who underwent Twin-Spiral DECT after endovascular stroke therapy. Ten patients were used to generate a device-specific parameter (“y”) using an AI-based neural network (SynthSR). This parameter was integrated into the post-processing algorithm for edema map generation. Quantitative Hounsfield unit (HU) measurements were used to assess density differences in ischemic brain tissue across conventional virtual non-contrast (VNC) images and edema maps. Results: The median HU of infarcted tissue in conventional mixed DECT was 33.73 ± 4.58, compared to 22.96 ± 3.81 in default VNC images. Edema maps with different smoothing filter settings showed values of 14.39 ± 4.96, 14.50 ± 3.75, and 15.05 ± 2.65, respectively. All edema maps demonstrated statistically significant HU differences of infarcted tissue compared to conventional VNC images ($p<0.001$) while maintaining the density values of non-infarcted brain tissue. Conclusions: Enhancing the post-processing algorithm of conventional virtual non-contrast imaging improves infarct detection compared to standard mixed or virtual non-contrast reconstructions in Dual-Energy CT. Full article

Background/Objectives: The aim of this study was to determine whether extracellular volume (ECV) fraction as determined by contrast-enhanced computed tomography (CECT) can help distinguish between autoimmune pancreatitis (AIP) and pancreatic ductal adenocarcinoma (PDAC). Methods: Participants comprised 101 patients, including 20 diagnosed with AIP (AIP group), 42 with histologically confirmed PDAC (PDAC group), and 39 without pancreatic disease (healthy group). Contrast enhancement (CE) was calculated as CT attenuation in Hounsfield units [HU] on equilibrium-phase CECT–CT attenuation on pre-contrast CT. The ECV fraction was calculated by measuring the region of interest within the pancreatic region and aorta on pre-contrast and equilibrium-phase CECT. CT measurements were compared among groups. CE and ECV fractions were also compared for diffuse (n = 12) and focal or segmental types (n = 8). Focal- or segmental-type AIP was defined as the involvement of one or two pancreas segments. Diagnostic efficacy was evaluated through receiver operating characteristic (ROC) analyses. Results: CE and ECV fractions differed significantly between the groups (p < 0.001 each). CE was significantly higher in the AIP group (56.8 ± 7.9 HU) than in the PDAC group (42.3 ± 17.0 HU, p < 0.001) or healthy group (32.2 ± 6.1 HU, p < 0.001). ECV fraction was significantly higher in the AIP group (47.2 ± 7.3%) than in the PDAC group (31.7 ± 12.0%, p < 0.001) or healthy group (27.5 ± 5.4%, p < 0.001). In the AIP group, no significant differences in CE (56.7 ± 8.2 HU vs. 56.9 ± 8.1 HU; p = 1.000) or ECV fraction (48.0 ± 5.6% vs. 46.6 ± 8.4%; p = 0.970) were seen between diffuse and focal or segmental types. Areas under the ROC curve for differentiating AIP from PDAC were 0.78 for CE and 0.86 for ECV fraction, showing no significant difference (p = 0.083). Conclusions: ECV fraction might be clinically useful in differentiating AIP from PDAC. Full article

Background: Prehabilitation programs improve postoperative outcomes in vulnerable patients undergoing major surgery. However, current screening tools such as the Malnutrition Universal Screening Tool (MUST) may lack the sensitivity needed to identify those who would benefit most. Muscle quality assessed by Computed Tomography (CT), specifically muscle radiodensity in Hounsfield Units (HUs), has emerged as a promising alternative for risk stratification. Objective: To evaluate the prognostic performance of CT-derived muscle radiodensity in predicting adverse postoperative outcomes in colorectal cancer patients, and to compare it with the performance of the MUST score. Methods: This single-center cross-sectional study included 201 patients with non-metastatic colon cancer undergoing elective laparoscopic resection. Patients were stratified based on enrollment in a multimodal prehabilitation program, either within an Enhanced Recovery After Surgery (ERAS) protocol or a non-ERAS pathway. Nutritional status was assessed using MUST, SARC-F questionnaire (strength, assistance with walking, rise from a chair, climb stairs, and falls), and the Global Leadership Initiative on Malnutrition (GLIM) criteria. CT scans at the L3 level were analyzed using automated segmentation to extract muscle area and radiodensity. Postoperative complications and hospital stay were compared across nutritional screening tools and CT-derived metrics. Results: MUST shows limited sensitivity (<27%) for predicting complications and prolonged hospitalization. In contrast, CT-derived muscle radiodensity demonstrates higher discriminative power (AUC 0.62–0.69), especially using a 37 HU threshold. In the non-ERAS group, patients with HU ≤ 37 had significantly more complications (33% vs. 15%, p = 0.036), longer surgeries, and more severe events (Clavien–Dindo ≥ 3). Conclusions: Opportunistic CT-based assessment of muscle radiodensity outperforms traditional screening tools in identifying patients at risk of poor postoperative outcomes, and may enhance patient selection for prehabilitation strategies like the ERAS program. Full article

Objectives: This study investigated the potential of Hounsfield unit (HU) values obtained from computed tomography (CT) scans as predictors of mechanical complications (MCs) in patients undergoing long-segment spinal fusion involving the pelvis. Additionally, it identified a threshold HU value associated with an increased risk of MCs. Methods: We conducted a retrospective, multicenter review of patients who underwent long-segment spinal fusion involving the pelvis, with a minimum follow-up period of two years. Patients were categorized based on the presence or absence of postoperative MCs. Both preoperative and postoperative radiographic parameters were analyzed, and HU values were quantified from CT images. Logistic regression modeling was used to identify independent risk factors for MCs. Results: Among 129 patients, 33 (25.6%) developed MCs, including proximal and distal junctional failures, rod fractures, and cases necessitating re-operation. The HU values were significantly lower in the MC group, whereas conventional bone mineral density (BMD) measurements showed no significant difference. Global alignment parameters, such as the sagittal vertical axis (SVA) and global tilt (GT), were consistently higher in patients with MCs. Receiver operating characteristic analysis identified 131 HU as the optimal cut-off, yielding a sensitivity of 56.4% and a specificity of 69.7%. Multivariate analysis confirmed that lower HU values were independently associated with the occurrence of MCs. Conclusions: Lower HU values and larger radiological global alignment parameters are significant predictors of MCs in patients undergoing surgery for adult spinal deformity. These findings underscore the importance of CT-based quantitative assessments in preoperative planning. Full article

The decision to remove a bullet from a gunshot victim depends on its location and associated medical risks, with surgical extraction often not indicated. Radiological imaging plays a vital role in assessing gunshot wounds and locating bullets, and it is essential in both clinical and forensic contexts. This narrative review examines the use of computed tomography (CT) for virtual bullet analysis, providing insights into shape, design, fragmentation, and material composition. Traditional 2D X-ray imaging, though commonly used, has limitations in accurately assessing caliber and position due to magnification and its 2D nature. In contrast, CT scans generate 3D reconstructions for detailed and precise examination, overcoming challenges such as metal artifacts with techniques such as extended Hounsfield unit (HU) reconstructions. These methods enhance the visualization of metal objects, allowing for better analyses of lodged bullets. Dual-energy CT further differentiates materials, such as lead and copper, using HU value differences at two energy levels. These advancements enable the virtual classification, shape analysis, and material identification of bullets in forensic investigations, even when the bullet remains in the body. As CT technology progresses, its forensic applications are expected to improve, providing more accurate and comprehensive differentiations of bullet types in future cases. Full article

This study evaluated attenuation values of lumbar epaxial musculature in dogs with acute spinal pathology using computed tomography (CT) and compared them with values in dogs without spinal disease. Sixty client-owned dogs were included: thirty dogs with thoracolumbar spinal lesions (intervertebral disc herniation) and thirty control dogs without spinal abnormalities. Mean Hounsfield unit (HU) values of epaxial muscles (multifidus–longissimus–iliocostalis group) were measured bilaterally at three lumbar levels for each dog—one level cranial to the lesion, the lesion level, and one level caudal to the lesion; for controls, the corresponding segments were T13, L1, L2, and L3. Dogs with spinal pathology showed a significant local decrease in muscle HU at the lesion site (average ~48 HU) compared to the segment cranial to the lesion (~50–51 HU, p < 0.01). In contrast, control dogs had relatively uniform muscle HU (~52–54 HU) across T13–L3 with no significant differences between these levels. Side to side differences were minimal in both groups. A logistic regression using the HU drop between segments correctly classified ~70% of cases, indicating moderate diagnostic value. Age and breed influenced overall muscle HU; older dogs had lower values (r = –0.39, p = 0.03 in controls), and French Bulldogs showed lower HU than other breeds. In conclusion, dogs with acute thoracolumbar disc herniation exhibit a focal reduction in paraspinal muscle HU at the lesion level. This acute change is subtle but detectable with CT and may serve as an additional indicator of lesion presence or chronicity, although its clinical utility requires further investigation in larger studies. Full article

Accurate preoperative image processing in markerless image-guided surgeries is an important task. However, preoperative planning highly depends on the quality of medical imaging data. In this study, a novel algorithm for outer skin layer extraction from head computed tomography (CT) scans is presented and evaluated. Axial, sagittal, and coronal slices are processed separately to generate spatial data. Each slice is binarized using manually defined Hounsfield unit (HU) range thresholding to create binary images from which valid contours are extracted. The individual points of each contour are then projected into three-dimensional (3D) space using slice spacing and origin information, resulting in uniplanar point clouds. These point clouds are then fused through geometric addition into a single enriched triplanar point cloud. A two-step downsampling process is applied, first at the uniplanar level and then after merging, using a voxel size of 1 mm. Across two independent datasets with a total of 83 individuals, the merged cloud approach yielded an average of 11.61% more unique points compared to the axial cloud. The validity of the triplanar point cloud reconstruction was confirmed by a root mean square (RMS) registration error of 0.848 ± 0.035 mm relative to the ground truth models. These results establish the proposed algorithm as robust and accurate across different CT scanners and acquisition parameters, supporting its potential integration into patient registration for markerless image-guided surgeries. Full article

Peripheral nerve injuries are a significant concern in surgical procedures, often leading to chronic pain and functional impairment. Despite advancements in imaging, preoperative and intraoperative visualization of peripheral nerves remains a challenge. This study introduces and evaluates a novel tri-iodinated lidocaine-based contrast agent for computed tomography neurography, aiming to enhance the intraoperative visibility of peripheral nerves in vivo. A tri-iodinated lidocaine analogue was synthesized and characterized for its radiodensity, sodium channel binding and nerve affinity. Sodium channel affinity was performed using molecular docking. In vitro contrast enhancement was assessed by comparing the agent’s Hounsfield unit (HU) values with those of Omnipaque, a clinically approved contrast medium. In vivo imaging was conducted on rat sciatic nerves using micro-CT, followed by ex vivo validation. Nerve conduction blockade was assessed via electrical stimulation and histological analysis was performed to evaluate neurotoxicity. Experimental results revealed the tri-iodinated lidocaine analogue to have similar or higher affinity toward voltage-gated sodium channels than the parent lidocaine and a radiodensity comparable to the commercial CT contrast agent Omnipaque in vitro. In vivo, the contrast agent provided CT visualization of the sciatic nerve, with a significant increase in HU values compared to untreated nerves. Electrical stimulation confirmed transient nerve conduction blockade without observable histological damage, supporting its dual role as an imaging and nerve-blocking agent. This study presents a novel tri-iodinated lidocaine-based contrast agent that enables clear CT visualization of peripheral nerves while maintaining reversible nerve inhibition. These findings support its potential application in preoperative planning and intraoperative nerve protection to reduce surgical nerve injuries. Further studies are warranted to optimize imaging conditions and evaluate its clinical feasibility. Full article

Background/Objectives: Bone mineral density (BMD) loss leads to osteoporosis, significantly increasing fracture risk in both the axial and peripheral skeleton. The extent to which it is possible to estimate the degree of osteoporosis in the hip by determining the density in Hounsfield Unit (HU) measurements derived from computed tomography (CT) scans and to calculate quantitative BMD and T values from the HU values should be examined. Methods: A total of 240 patients (mean age: 64.9 ± 13.1 years, BMI: 26.8 ± 6.8 kg/m²) underwent CT-based BMD assessments using CTXA-Hip. Subregions of the proximal femur, including the femoral head, femoral neck, and intertrochanteric region, were analyzed for cancellous density in HUs using circular and irregular region-of-interest (ROI) measurements. Correlations between HU values and DEXA-equivalent BMD (mg/cm²) and T values were computed. Predictive power for osteoporosis was evaluated using ROC curve analysis. Results: Cancellous bone density in the proximal femur showed a significant decline with increasing age and decreasing BMI (p < 0.05). The median BMD for the entire hip was 0.684 mg/cm², and the median HU value for the proximal femur was 123.15. Strong correlations were observed between HU values and BMD (R² = 0.904, p < 0.001) and T values (R² = 0.911, p < 0.001). A T value of −2.5 corresponded to an HU value of 95.79 in the entire femur. ROC analysis demonstrated high sensitivity (0.92) and specificity (0.93) for HU-based osteoporosis prediction. Conclusions: HU measurements provide a reliable method for estimating BMD and T values in the proximal femur, offering a valuable diagnostic tool for osteoporosis. The highest predictive accuracy was achieved when using an irregular ROI from the entire proximal femoral region. Full article

Anterior cruciate ligament (ACL) rupture and patellar dislocation (PD) are common knee injuries. Dual-energy X-ray absorptiometry (DXA) and computed tomography (CT) are widely used clinical diagnostic tools. The aim was to investigate the characteristics of knee bone mineral density (BMD) in patients with ACL rupture and PD and to explore the relationship between BMD and Hounsfield unit (HU) values. This prospective cross-sectional study included 32 ACL rupture and 32 PD patients assessed via DXA and CT. BMD and CT measurements were taken from regions of interest in the femoral and tibial condyles. Statistical analyses included t-tests and mixed-effects models. The results showed that BMD in the PD group was significantly lower than in the ACL group (p < 0.05). The HU values of cortical bone in the femur and tibia differed significantly between the ACL group and the PD group (p < 0.05). The BMD of the femur and tibia showed significant correlations with the HU values of cancellous bone and cortical bone (p < 0.05). The conclusion was that PD patients had lower BMD and HU values in the femur and tibia compared to patients with ACL ruptures, particularly in the cortical bone of the tibia, and there was a strong correlation between HU value and BMD. Full article

Objectives: Mandibular tori (bilateral, asymptomatic, lingual mandibular protuberances) often remain untreated. When considering surgical resection, understanding the shape, size, and position of the tori at the bone level is crucial. However, collecting accurate information regarding these characteristics is challenging in cases where the oral mucosa is prominent on the floor of the mouth. Methods: We conducted retrospective surveys at Fukuoka Dental College Medical and Dental General Hospital using computed tomographic (CT) image analysis software (Simplant Pro 18.0). The specific aims of this study were to evaluate the appearance rate of mandibular tori by morphological type, size, location, and CT values and their relationship with the remaining teeth in 1176 patients. These patients underwent simple mandibular CT tomography. We used t-tests to analyze the data. Results: Approximately 10% of the identified tori were pedunculated and difficult to diagnose through visual inspection alone. In all the age groups > 30 years, patients with mandibular tori had a lower rate of tooth loss and a higher rate of remaining occlusal support than healthy subjects. The mean CT value of the mandibular tori was >1350 Hounsfield units (HU). Conclusions: These findings provide insights into future classification and treatment planning for mandibular tori, including that in regard to mandibular ridge resection and factors that may contribute to mandibular torus development or progression, and validate the use of excised bone tissue as a bone graft material. Full article

Bone mineral density (BMD) is an essential indicator of bone strength and plays a crucial role in the clinical management of various spinal pathologies. Hounsfield units (HUs) calculated from computed tomography (CT) scans are a well-established, effective, and non-invasive method to determine bone density in the lumbar spine when juxtaposed to dual-energy X-ray absorptiometry (DEXA) scans, the gold standard for assessing trabecular bone density. Only recently have studies begun to investigate and establish HUs as a reliable and valid alternative for bone quality assessment in the cervical spine as well. In addition, multiple recent studies have identified cervical HUs as an accurate predictor of cage subsidence, an undesired complication of anterior cervical discectomy and fusion (ACDF) of anterior cervical corpectomy and fusion (ACCF) procedures. Subsidence involves migration of the spinal fusion cage into vertebral bodies, causing a loss of disk space, negatively altering spine alignment, and possibly necessitating further unwanted surgical intervention. Using the PRISMA-ScR checklist and the registered scoping review protocol (INPLASY2024100126), this review explores the current research on the use of cervical spine HU measurements as both a determinant of BMD and as a prognosticator of postoperative subsidence following cervical spine procedures (i.e., ACDFs and ACCFs) with the aim of improving clinical and surgical outcomes. Full article

This study aimed to 3D print a patient-specific chest phantom simulating multiple lung nodules to optimise low-dose Computed Tomography (CT) protocols for lung cancer screening. The chest phantom, which was developed from a single patient’s chest CT images, was fabricated using a variety of materials, including polylactic acid (PLA), Glow-PLA, acrylonitrile butadiene styrene (ABS), and polyurethane resin. The phantom was scanned under different low-dose (LDCT) and ultra-low-dose CT (ULDCT) protocols by varying the kilovoltage peak (kVp) and milliampere-seconds (mAs). Subjective image quality of each scan (656 images) was evaluated by three radiologists using a five-point Likert scale, while objective image quality was assessed using signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR). Anatomical conformance was assessed by comparing tissue diameters of the phantom and patient scans using Bland–Altman analysis. The phantom’s lung tissue, lung nodules, and diaphragm demonstrated radiation attenuation comparable to patient tissue, as measured in Hounsfield Units (HU). However, significant variations in HU were observed for the skin, subcutaneous fat, muscle, bone, heart, lung vessels, and blood vessels compared to patient tissues, with values ranging from 93.9 HU to −196 HU (p < 0.05). Both SNR and CNR decreased as the effective dose was reduced, with a strong positive linear correlation (r = 0.927 and r = 0.931, respectively, p < 0.001, Jamovi, version 2.3.28). The median subjective image quality score from radiologists was 4, indicating good diagnostic confidence across all CT protocols (κ = −0.398, 95% CI [−0.644 to −0.152], p < 0.002, SPSS Statistics, version 30). An optimal protocol of 80 kVp and 30 mAs was identified for lung nodule detection, delivering a dose of only 0.23 mSv, which represents a 96% reduction compared to standard CT protocols. The measurement error between patient and phantom scans was −0.03 ± 0.14 cm. These findings highlight the potential for significant dose reductions in lung cancer screening programs. Further studies are recommended to improve the phantom by selecting more tissue-equivalent materials. Full article

Background: Osteoporosis is commonly evaluated using dual-energy X-ray absorptiometry (DXA) for bone mineral density (BMD). Non-contrast computed tomography (CT) scans provide an alternative for opportunistic osteoporosis assessment. This study aimed to evaluate screening thresholds for osteoporosis based on CT attenuation values in Hounsfield units (HU) of L1–L4 vertebrae from CT scans of the abdominal region, compared to DXA assessments of the lumbar spine and hips. Methods: Conducted retrospectively over approximately two years, the analysis included 109 patients who had both CT and DXA scans within 12 months, excluding those with metal artifacts affecting the vertebrae. CT attenuation values in the trabecular region of the vertebrae were measured and compared among three groups based on the lowest T-score from DXA. Results: In a predominantly female cohort (mean age 66.3 years), the lowest CT attenuation values for L1–L4 vertebrae showed a moderate correlation with the lowest T-score, with a Pearson correlation coefficient of 0.542 (95% CI: 0.388, 0.667). A HU threshold of ≤142 at the L1 vertebra showed 91.9% sensitivity and 48.4% specificity, while a threshold of ≤160 HU showed 97.3% sensitivity and 31.3% specificity for screening osteoporosis. Conclusions: This study supports the use of non-contrast CT with these HU thresholds as an opportunistic tool for osteoporosis assessment. Full article

Background: This study aimed to assess whether preoperative Hounsfield unit (HU) values differ in short-term clinical outcomes after lateral lumbar interbody fusion (LLIF) surgery. Methods: In a retrospective analysis, 109 patients undergoing LLIF for lumbar degenerative diseases (LDD) were reviewed. Preoperative Computed Tomography (CT) scans measured HU values at the L1–L4 vertebrae, dividing patients into low and high HU groups. After conducting a cluster analysis of preoperative Hounsfield unit (HU) values, patients were categorized into low and high HU groups using propensity score matching (PSM). The outcomes measured one-year post-surgery included pain intensity (Numeric Rating Scales for Low Back Pain (NRS_LBP), Leg Pain (NRS_LP), and Leg Numbness (NRS_LN)) and quality of life (Japanese Orthopedic Association Back Pain Evaluation Questionnaire: JOABPEQ). Results: After PSM, there were 26 patients in each group. Significant improvements were noted in both low and high HU groups post-surgery, with the low HU group showing a decrease in NRS_LBP from 6.2 to 3.7, NRS_LP from 7.4 to 2.5, and NRS_LN from 6.4 to 3.0. The high HU group exhibited similar improvements (NRS_LBP: 6.5 to 3.6, NRS_LP: 6.3 to 2.5, NRS_LN: 6.2 to 2.4). JOABPEQ scores improved significantly in both groups across all domains, with no significant differences observed. Preoperative HU values have little correlation with the short-term outcomes of pain and quality of life in LLIF surgery. Conclusions: This study suggests reconsidering the role of HU values following indirect decompression via LLIF, particularly in evaluating pain and patient-reported outcome measures in patients with LDD. Full article