Application of double-layer detector spectral CT calcicum supression technique in the diagnosis of traumatic bone marrow edema in the knee.

Objective: To investigate the accuracy of calcicum supression (CaSupp) technique derived from double-layer detector spectral computed tomography (DSCT) in the diagnosis of traumatic bone marrow edema in the knee. Methods: Twenty-three patients with trauma in the knee who underwent DSCT and Magnetic Resonance Imaging (MRI) in the Third Hospital of Hebei Medical University from October 2021 to March 2022 were retrospectively collected. To make the evaluation more detailed and accurate, each knee was divided into 10 partitions. Bone marrow edema in each partition of the knee was evaluated by two physicians (physician A and B) using CaSupp images combined with conventional CT-CaSupp fusion false-color images. MRI results were used as the gold standard and the accuracy of the CaSupp technique was analyzed in the diagnosis of traumatic bone marrow edema in the knee. The CaSuppCT values of the normal bone marrow area and the bone marrow edema area were delineated, and receiver operating curve (ROC curve) was drawn to find the optimal cut-off value of CaSuppCT as the quantitative parameter for the diagnosis of bone marrow edema. Results: The diagnostic sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of physician A were 83.1 %, 98.1 %, 95.5 % and 92.1 %, respectively; those of physician B were 93.5 %, 97.4 %, 94.7 % and 96.8 %, respectively. The CaSuppCT values in the bone marrow edema areas were higher than those in the normal areas, and the difference was statistically significant. The area under the receiver operating characteristic curve (AUC) of the CaSuppCT values was 0.979, and the cut-off value was 7.05Hu*. The corresponding diagnostic sensitivity was 87.0 %, and specificity was 100.0 %. Conclusion: The CaSupp technique derived from DSCT has high sensitivity and specificity in the detection of traumatic bone marrow edema in the knee, and can provide more imaging information for clinical practice.

A quantitative analysis of spectral computed tomography characteristics of osseous metastases.

INTRODUCTION: Spectral detector computed tomography (SDCT) is a recent advancement that enables elemental material decomposition which could improve the detection of osseous metastases in the oncologic patient. METHODS: Sixteen patients who underwent oncologic staging SDCT as well as WBBS with Technetium-99 m hydroxydiphosphonate (Tc99m HDP) were included in this retrospective study. A total of 50 osseous metastases were identified and confirmed on bone scintigraphy. Quantitative ROI-based measurements of each lesion and a similar region of normal bone were performed, and the acquired spectral data were used for comparison. These parameters included effective atomic number (Zeff ), electron density (%EDW) and calcium suppression (HU). Receiver operating characteristic (ROC) analysis was performed. RESULTS: In comparison to normal bone, osseous metastases showed statistically significantly elevated values in effective atomic number, electron density and calcium suppression. ROC analysis demonstrated outstanding discrimination with area under the curve (AUC) values of 0.934 and 0.915 for effective atomic number and electron density, and excellent discrimination with an AUC value of 0.884 for calcium suppression. Threshold values of effective atomic number (Zeff ) >9.7, electron density >115% EDW and calcium suppression values >0 HU were demonstrated to be able to differentiate an osseous lesion from normal bone with a sensitivity of 82%, 82% and 84% and a specificity of 86%, 92% and 88% respectively. CONCLUSION: Spectral analysis of osseous metastases demonstrated significantly elevated values in effective atomic number, electron density and calcium suppression as compared to normal bone which would be useful adjunct quantitative parameters in CT imaging to increase diagnostic confidence.

Metastatic pulmonary calcification: First report of pulmonary calcium suppression using dual-energy CT.

Metastatic pulmonary calcification is an underdiagnosed metabolic lung disease characterized by diffuse calcium deposition in the lungs, often associated with secondary hyperparathyroidism due to chronic renal failure. A 31-year-old man with chronic renal failure initially presented with diffuse pain symptoms, deterioration of general condition, and respiratory insufficiency. Noncontrast-enhanced computed tomography of the chest was performed using a spectral-detector-based dual-energy CT. It showed multiple, centrilobular, ground-glass opacities, and nodules, ultimately leading to the diagnosis. Calcium suppression proved to be highly useful to classify the pulmonary alterations.

Bone marrow edema in traumatic vertebral compression fractures: Diagnostic accuracy of dual-layer detector CT using calcium suppressed images.

PURPOSE: To evaluate calcium suppressed images (CaSupp) in dual-layer detector computed tomography (DLCT) for the detection of bone marrow edema (BME) in vertebral fractures. MATERIALS AND METHODS: The retrospective study was approved by the institutional review board. 34 patients with synchronous DLCT and MRI, who were diagnosed with one or more acute vertebral fractures, were included. MRI were systematically analyzed as reference standard. Two blinded and independent readers evaluated CaSupp for vertebral BME. Additionally, both readers determined the optimal calcium suppression indices (CaSupp-I) for visualization of BME in consensus and correlated the CaSupp-I with parallel measurement of trabecular density as surrogate parameter for bone mineral density. ROI-based measurements of the contrast-to-noise ratios (CNR) were also conducted. Interrater agreement was determined by kappa-statistics. CNR were analyzed using Wilcoxon signed rank test. RESULTS: Fifty-seven acute fractured vertebrae out of 383 vertebrae (14.9%) were found. CaSupp yielded an average sensitivity of 87% and specificity of 99%, a positive predictive value of 95%, a negative predictive value of 98% and an accuracy of 97% for the detection of fracture-associated edema. Interrater agreement was excellent (kappa 0.91). Increase in CNR of BME correlated with increasing CaSupp-I. Edema adjacent to the cortical endplates was better visualized using CaSupp-I of 70 and 80, while extensive edema was better visualized using a CaSupp-I of 90 and 100 (chi2 < 0.0001). No correlation between optimal CaSupp-I and trabecular density was found (p > 0.2). CONCLUSION: CaSupp reconstructed from DLCT enable visualization and detection of BME in traumatic fractured vertebrae with high diagnostic accuracy using CaSupp-I of 70-100.

The diagnostic value of dual-layer detector spectral CT calcium suppression technique in acute and chronic thoracolumbar compression fractures / 中华放射学杂志

Objective:To evaluate the diagnostic value of spectral CT calcium suppression (CaSupp) technique in acute and chronic thoracolumbar compression fractures.Methods:A total of 31 patients with thoracolumbar compression fractures were given spectral CT and MR scans from March to October 2020 in the Second Hospital of Shanxi Medical University. Acute and chronic vertebral fractures were diagnosed by doctor A and B based on CaSupp diagram, and the consistency between the two doctors was evaluated by Kappa test. CT values of fractured vertebra and adjacent normal vertebra were measured on conventional CT and CaSupp graphs respectively, and the CT value difference between fractured vertebra and adjacent vertebra was calculated. Independent sample t-test was used to compare the conventional CT value and CT value difference, CaSupp CT value and CT value difference between acute and chronic fractured vertebra. Using MRI as the gold standard, the ROC curves were drawn to evaluate the subjective diagnostic efficacy of physicians and the diagnostic efficacy of each quantitative parameter. DeLong test was used to compare the area under the curve (AUC) of each quantitative parameter in pairs. Results:The number of vertebral bodies in acute and chronic compression fractures diagnosed by MRI was 48 and 11 respectively. The Kappa value of subjective diagnosis of acute and chronic vertebral fractures by doctors A and B was 0.782, and the AUC, sensitivity, specificity were 0.882 and 0.857, 85.4% and 89.6%, 90.9% and 81.8%, respectively. The differences of conventional CT value, CaSupp CT value and CaSupp CT value difference between acute and chronic compression fractures were statistically significant (all P<0.05), and the AUC values of conventional CT value, CaSupp CT value, conventional CT value difference and CaSupp CT value difference were 0.824, 0.930, 0.706 and 0.934, respectively. Pair comparison showed that the AUC of the CaSupp CT value and CaSupp CT value difference was greater than that of conventional CT value difference, with statistically significant differences ( Z=2.014, P=0.044, Z=2.028, P=0.043), while there were no statistically significant differences between other AUC values (all P>0.05). Conclusion:The dual-layer detector spectral CT CaSupp technique has high value in differentiating acute and chronic thoracolumbar compression fractures, and the CaSupp CT value and CaSupp CT value difference are recommended for diagnosis.