The Use of Computer Vision for Localization of Vertebrae on Midsagittal Computed Tomography Slices

To assess the clinical effectiveness and cost-effectiveness, in different patient groups, of the use of 64-slice or higher computed tomography (CT) angiography, instead of invasive coronary angiography (CA), for diagnosing people with suspected coronary artery disease (CAD) and assessing people with known CAD. Electronic databases were searched from 2002 to December 2006. Included studies were tabulated and sensitivity, specificity, positive and negative predictive values calculated. Meta-analysis models were fitted using hierarchical summary receiver operating characteristic curves. Summary sensitivity, specificity, positive and negative likelihood ratios and diagnostic odds ratios for each model were reported as a median and 95% credible interval (CrI). Searches were also carried out for studies on the cost-effectiveness of 64-slice CT in the assessment of CAD. The diagnostic accuracy and prognostic studies enrolled over 2500 and 1700 people, respectively. The overall quality of the studies was reasonably good. In the pooled estimates, 64-slice CT angiography was highly sensitive (99%, 95% CrI 97 to 99%) for patient-based detection of significant CAD (defined as 50% or more stenosis), while across studies the negative predictive value (NPV) was very high (median 100%, range 86 to 100%). In segment-level analysis compared with patient-based detection, sensitivity was lower (90%, 95% CrI 85 to 94%, versus 99%, 95% CrI 97 to 99%) and specificity higher (97%, 95% CrI 95 to 98%, versus 89%, 95% CrI 83 to 94%), while across studies the median NPV was similar (99%, range 95 to 100%, versus 100%, range 86 to 100%). At individual coronary artery level the pooled estimates for sensitivity ranged from 85% for the left circumflex (LCX) artery to 95% for the left main artery, specificity ranged from 96% for both the left anterior descending (LAD) artery and LCX to 100% for the left main artery, while across studies the positive predictive value (PPV) ranged from 81% for the LCX to 100% for the left main artery and NPV was very high, ranging from 98% for the LAD (range 95 to 100%), LCX (range 93 to 100%) and right coronary artery (RCA) (range 94 to 100%) to 100% for the left main artery. The pooled estimates for bypass graft analysis were 99% (95% CrI 95 to 100%) sensitivity, 96% (95% CrI 86 to 99%) specificity, with median PPV and NPV values across studies of 93% (range 90 to 95%) and 99% (range 98 to 100%), respectively. This compares with, for stent analysis, a pooled sensitivity of 89% (95% CrI 68 to 97%), specificity 94% (95% CrI 83 to 98%), and median PPV and NPV values across studies of 77% (range 33 to 100%) and 96% (range 71 to 100%), respectively. Sixty-four-slice CT is almost as good as invasive CA in terms of detecting true positives. However, it is somewhat poorer in its rate of false positives. It seems likely that diagnostic strategies involving 64-slice CT will still require invasive CA for CT test positives, partly to identify CT false positives, but also because CA provides other information that CT currently does not, notably details of insertion site and distal run-off for possible coronary artery bypass graft (CABG). The high sensitivity of 64-slice CT avoids the costs of unnecessary CA in those referred for investigation but who do not have CAD. Given the possible, although small, associated death rate, avoiding these unnecessary CAs through the use of 64-slice CT may also confer a small immediate survival advantage. This in itself may be sufficient to outweigh the very marginally inferior rates of detection of true positives by strategies involving 64-slice CT. The avoidance of unnecessary CA through the use of 64-slice CT also appears likely to result in overall cost savings in the diagnostic pathway. Only if both the cost of CA is relatively low and the prevalence of CAD in the presenting population is relatively high (so that most patients will go on to CA) will the use of 64-slice CT be likely to result in a higher overall diagnostic cost per patient. The main value of 64-slice CT may at present be to rule out significant CAD. It is unlikely to replace CA in assessment for revascularisation of patients, particularly as angiography and angioplasty are often done on the same occasion. Further research is needed into the marginal advantages and costs of 256-slice machines compared with 64-slice CT, the usefulness of 64-slice CT in people with suspected acute coronary syndrome, the potential of multislice computed tomography to examine plaque morphology, the role of CT in identifying patients suitable for CABG, and the concerns raised about repetitive use, or use of 64-slice or higher CT angiography in younger individuals or women of childbearing age.

Sensitivity of Newer-generation Computed Tomography Scanners for Subarachnoid Hemorrhage: A Bayesian Analysis

We analyzed the effectiveness of using 64-slice spiral computed tomography (CT) and perfusion imaging to guide argon-helium cryoablation treatment of liver cancer. In total, 60 cases of advanced hepatocellular carcinoma before surgery treated with argon-helium cryoablation were inlcuded in the present study. Retrospective summary of the 60 cases of metaphase and advanced liver cancer were used as the control group. The control group were treated using cryoablation with argon-helium knife. We used enhanced scanning with 64-slice spiral CT to define the extent of their lesions and prepared a plan of percutaneous cryoablation for the treatment. Intraoperatively, we used the dynamics of CT perfusion imaging to observe the frozen ablation range and decreased the rate of complications. After surgery, the patients were followed-up regularly by 64-slice CT. We used conventional X-ray, CT and magnetic resonance imaging (MRI) for pre-operative lateralization. Intraoperative X-ray or ultrasound guidance and follow-up with CT or MTI were added to determine the clinical effectiveness and prognosis. The results showed that the total effective rate was improved significantly and incidence rate of overall complications decreased markedly in the observation group. Following treatment, AFP decreased significantly while the total freezing area and time were reduced significantly. The median survival time was increased significantly in the observation group. The numeric values of hepatic arterial perfusion, portal vein perfusion and hepatic arterial perfusion index were all markedly lowered after treatment. Differences were statistically significant (P<0.05). In conclusion, the use of 64-slice spiral CT perfusion imaging may considerably improve the effects of liver cancer treatment using the argon-helium cryoablation. It extended the survival time and reduced complications.

The 256-slice computed tomography (CT) scanners with wider detector coverage and faster gantry rotation speed are now available. The performance of scanners that feature a rotation speed of 270 ms at coronary CT angiography (CCTA) has not been evaluated in patients with a higher heart rate. To evaluate the image quality of 256-slice CT with faster gantry rotation speed in patients undergoing CCTA. We enrolled 886 patients; 357(40.3%) underwent study on a 64-slice CT at a rotation speed of 420 ms, the other 529 (59.7%) were examined using a 256-slice CT scanner at 270 ms. Two observers judged the image quality of 2658 imaged coronary arteries on a 4-point scale. The mean image quality score was significantly higher for the 256 - than the 64-slice CT scans (3.94 ± 0.28 vs. 3.73 ± 0.61; P < 0.01). There was no significant difference in the image quality scores between 64 - and 256-slice scans in patients whose heart rate (HR) was <60 bpm. However, in patients whose HR exceeded 60 bpm these scores were significantly higher for 256-slice CT images (P < 0.01). CCTA performed on the 256-slice CT scanner yielded significantly better image quality in patients with an HR exceeding 60 bpm.

Computed tomography (CT) images are used for precise anatomical location of lesions and for accurate attenuation correction in single-photon emission computed tomography (SPECT) image reconstruction in SPECT/CT examination. The aim of this study was to verify the effects of varying CT collimation width and slice thickness on CT images and on CT attenuation corrected SPECT images. We acquired SPECT/CT images of a micro-coin phantom and the National Electrical Manufacturers Association body phantom filled with 99mTc-pertechnetate while varying the abovementioned CT parameters. The full width at half maximum of the slice sensitivity profile, the standard deviation of CT image background noise, and the radiation dose from CT scans were evaluated. Subsequently, the percentage contrast, background variability, and absolute recovery coefficient of the SPECT image were measured. Furthermore, we retrospectively reviewed the clinical bone SPECT images of 23 patients, and statistical testing of differences was performed. As the collimation width and reconstruction slice thickness of the CT image increased, z-axis resolution deteriorated, and background noise decreased. In addition, CT radiation dose decreased with increasing collimation width. Meanwhile, SPECT image quality and quantitative accuracy were unchanged with varying CT collimation width and slice thickness. There were no notable variations in clinical SPECT images and no statistically significant differences. When high-resolution CT slices on the z-axis are not required for clinical diagnosis, increasing collimation width or slice thickness can reduce the radiation dose and image noise with no influence on the quality of SPECT images .

Few articles have evaluated vertebral artery ostium stents using multislice computed tomography (CT). The purpose of our study was to evaluate the diagnostic performance of 64- and 16-slice CT for detecting significant in-stent restenosis after vertebral artery ostium stenting, and to identify factors affecting the accurate diagnosis by CT. We reviewed 57 stents scanned using 64-slice CT and 34 stents using 16-slice CT. The accuracy of CT for diagnosing significant in-stent restenosis (≥ 50% diameter narrowing) was calculated using conventional angiography as a reference standard. Possible factors influencing the diagnostic performance of CT were analyzed, such as CT scanner, image quality, and stent characteristics. With 64-slice CT, 46 (80.7%) of 57 stents were classified as evaluable, while with 16-slice CT, 28 (82.3%) of 34 stents were classified as evaluable. No stents with diameters ≤ 2.75 mm were evaluable. The respective results for 64- versus 16-slice CT were sensitivity 87.5% (95% confidence interval [CI] 47.3-99.7%) versus 100% (95% CI 15.8-100.0%), specificity 94.7% (95% CI 82.3%-99.4%) versus 96.2% (95% CI 80.4-99.9%). Factors reducing the accurate diagnosis were those associated with poor image quality, a diameter ≤ 2.75 mm, and drug-eluting stent type (p < 0.05). 64-slice and 16-slice CT scans are adequate in stents with diameters > 2.75 mm for the evaluation of in-stent restenosis after stent implantation in the vertebral artery ostium.

Tomodensitométrie thoracique chez l’enfant : un examen utile mais irradiant

A structure map as a visualization aid in three-dimensional treatment planning

Prevalence of Noncalcified Coronary Plaques by 64-Slice Computed Tomography in Patients With an Intermediate Risk for Significant Coronary Artery Disease

Usefulness of 4-, 8-, and 16-Slice Computed Tomography for Detection of Graft Occlusion or Patency After Coronary Artery Bypass Grafting

Purpose. Accurate localization and labeling of vertebrae in computed tomography (CT) is an important step toward more quantitative, automated diagnostic analysis and surgical planning. In this paper, we present a framework (called Ortho2D) for vertebral labeling in CT in a manner that is accurate and memory-efficient. Methods. Ortho2D uses two independent faster R-convolutional neural network networks to detect and classify vertebrae in orthogonal (sagittal and coronal) CT slices. The 2D detections are clustered in 3D to localize vertebrae centroids in the volumetric CT and classify the region (cervical, thoracic, lumbar, or sacral) and vertebral level. A post-process sorting method incorporates the confidence in network output to refine classifications and reduce outliers. Ortho2D was evaluated on a publicly available dataset containing 302 normal and pathological spine CT images with and without surgical instrumentation. Labeling accuracy and memory requirements were assessed in comparison to other recently reported methods. The memory efficiency of Ortho2D permitted extension to high-resolution CT to investigate the potential for further boosts to labeling performance. Results. Ortho2D achieved overall vertebrae detection accuracy of 97.1%, region identification accuracy of 94.3%, and individual vertebral level identification accuracy of 91.0%. The framework achieved 95.8% and 83.6% level identification accuracy in images without and with surgical instrumentation, respectively. Ortho2D met or exceeded the performance of previously reported 2D and 3D labeling methods and reduced memory consumption by a factor of ∼50 (at 1 mm voxel size) compared to a 3D U-Net, allowing extension to higher resolution datasets than normally afforded. The accuracy of level identification increased from 80.1% (for standard/low resolution CT) to 95.1% (for high-resolution CT). Conclusions. The Ortho2D method achieved vertebrae labeling performance that is comparable to other recently reported methods with significant reduction in memory consumption, permitting further performance boosts via application to high-resolution CT.

Multidetector Computed Tomography for the Diagnosis of Coronary Artery Disease: A Systematic Review

This study aimed to describe the anatomical features and variations of the abdominal aorta and its major visceral branches - the celiac trunk, superior mesenteric artery (SMA), and inferior mesenteric artery (IMA) - using 128-slice computed to-mography (CT) imaging. A descriptive, retrospective study was conducted on 193 adult Vietnamese patients who underwent contrast-enhanced 128-slice abdominal CT scans at Tam Anh General Hospital between December 2023 and December 2024. Origins, diameters, branching angles, and anatomical variants were recorded and an-alyzed using MIP and 3D VR reconstructions. Variations were classified using Uflack-er's (celiac trunk) and Kornafel's (SMA) systems. The most common origin levels were T12-L1 for the celiac trunk (33.7%), L1 for the SMA (36.3%), and L3 for the IMA (30.6%). Classical branching patterns were present in 68.0% for the celiac trunk, 96.3% for the SMA, and 97.4% for the IMA. Several uncommon variants, such as hepatosplenic trunks and IMA origin from the SMA, were identified. 128-slice CT provides high-resolution imaging to reliably assess vascular anatomy. Significant anatomical variation exists in the abdominal aorta and its branches, under-lining the importance of individualized preoperative evaluation.

This study aimed to compare the sensitivity and accuracy for the detection of small lesions in patients with hepatocellular carcinoma (HCC) using gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid (Gd-EOB-DTPA) dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and 64-slice computed tomography (CT) enhanced scanning, and to evaluate the necessity to perform MRI in patients diagnosed with HCC by CT.The clinical data from 209 patients with HCC diagnosed prior to surgery in the Affiliated Hospital of Guilin Medical University, China were retrospectively analyzed. The 64-slice dynamic contrast-enhanced multi-detector CT (MDCT) and 3.0 T Gd-EOB-DTPA DCE MRI procedures were successively carried out on all patients who were enrolled in a self-controlled study including detection and diagnosis of HCC lesions by MRI and CT, respectively.A total of 243 lesions were detected and both imaging methods could accurately detect lesions of diameter >2 cm. For lesions <2 cm, MRI detected 47, while CT detected 25 lesions indicating that the detection rate of MRI was 88% higher than that of CT. In addition, MRI detected lesions in 15 cases (7.81% in the total of 209 cases) that were not diagnosed by CT. Among these cases, 2 patients were diagnosed to have no lesion by CT.Gd-EOB-DTPA DCE-MRI performed as a routine check prior to surgery in HCC patients can improve the detection of small HCC lesions.

BackgroundBased on the images generated from two multi-slice computed tomography (CT) scanners, we intended to compare the five-line sign of normal interlobular fissures produced on axial or oblique maximum intensity projection (MIP) reconstructions using different algorithms.MethodsTwo groups of 50 subjects underwent either 16-slice or 256-slice spiral unenhanced chest CT. None of them in either group displayed any abnormality. For each case, maximum intensity projection (MIP) data were used to calculate the axial or oblique projection using four algorithms: standard axial, standard oblique, high-resolution axial, and high-resolution oblique algorithm. The results were then used to reconstruct images of six locations of the lung. The clarity of the five-line sign of the reconstructed MIPs for the interlobular fissures was determined and graded as 1 (unclear), 2 (barely clear), or 3 (clear). Comparisons of the rate and the degree of clarity were performed using non-parametric tests.ResultsData from both the 16-slice and 256-slice CT revealed that the standard oblique algorithm was the best among the four methods for presenting clear images of the five-line sign (p < 0.001), whereas the high-resolution axial algorithm was the worst. In addition, the two CT units exhibited no significant differences in the clarity of the five-line sign (p = 0.273).ConclusionsThe standard oblique algorithm was the best approach to reveal the five-line sign of normal lung fissures. Both 16-slice and 256-slice CT were effective for reconstructing the sign.