Maximum Intensity Projection Technique Research Articles

The Atlas of the Inferior Mesenteric Artery and Vein under Maximum-Intensity Projection and Three-Dimensional Reconstruction View

(1) Background: Understanding vascular patterns is crucial for minimizing bleeding and operating time in colorectal surgeries. This study aimed to develop an anatomical atlas of the inferior mesenteric artery (IMA) and vein (IMV). (2) Methods: A total of 521 patients with left-sided colorectal cancer were included. IMA and IMV patterns were identified using maximum-intensity projection (MIP) and three-dimensional (3D) reconstruction techniques. The accuracy of these techniques was assessed by comparing them with surgical videos. We compared the amount of bleeding and operating time for IMA ligation across different IMA types. (3) Results: Most patients (45.7%) were classified as type I IMA, followed by type II (20.7%), type III (22.6%), and type IV (3.5%). Newly identified type V and type VI patterns were found in 6.5% and 1% of patients, respectively. Of the IMVs, 49.9% drained into the superior mesenteric vein (SMV), 38.4% drained into the splenic vein (SPV), 9.4% drained into the SMV–SPV junction, and only 2.3% drained into the first jejunal vein (J1V). Above the root of the left colic artery (LCA), 13.1% of IMVs had no branches, 50.1% had one, 30.1% had two, and 6.7% had three or more branches. Two patients had two main IMV branches, and ten had IMVs at the edge of the mesocolon with small branches. At the IMA root, 37.2% of LCAs overlapped with the IMV, with 34.0% being lateral, 16.9% distal, 8.7% medial, and both the marginal type of IMV and the persistent descending mesocolon (PDM) type represented 1.4%. MIP had an accuracy of 98.43%, and 3D reconstruction had an accuracy of 100%. Blood loss and operating time were significantly higher in the complex group compared to the simple group for IMA ligation (p < 0.001). (4) Conclusions: A comprehensive anatomical atlas of the IMA and IMV was provided. Complex IMA patterns were associated with increased bleeding and operating time.

The guiding value of the cinematic volume rendering technique in the preoperative diagnosis of brachial plexus schwannoma.

This study aimed to explore and compare the guiding value of Maximum Intensity Projection (MIP) and Cinematic Volume Rendering Technique (cVRT) in the preoperative diagnosis of brachial plexus schwannomas. We retrospectively analyzed the clinical and imaging data of 45 patients diagnosed with brachial plexus schwannomas at the First Affiliated Hospital of Zhengzhou University between January 2020 and December 2022. The enhanced three-dimensional short recovery time inversion-recovery fast spin-echo imaging (3D-STIR-SPACE) sequence served as source data for the reconstruction of MIP and cVRT. Two independent observers scored the image quality and evaluated the location of the tumor and the relationship between the tumor and the brachial plexus. The image quality scores of the two reconstruction methods were compared using the nonparametric Wilcoxon signed-rank test, and the consistency between the image and surgical results was assessed using the weighted kappa. Compared to MIP images, cVRT images had a better performance of overall image quality (p < 0.001), nerve and lump visualization (p < 0.001), spatial positional relationship conspicuity (p < 0.001), and diagnostic confidence (p < 0.001). Additionally, the consistency between the cVRT image results and surgical results (kappa =0.913, P<0.001) was higher than that of the MIP images (kappa =0.829, P<0.001). cVRT provides a high guiding value in the preoperative diagnosis of brachial plexus schwannomas and is an important basis for formulating surgical plans.

Artificial intelligence for the detection of sacroiliitis on magnetic resonance imaging in patients with axial spondyloarthritis.

Magnetic resonance imaging (MRI) is important for the early detection of axial spondyloarthritis (axSpA). We developed an artificial intelligence (AI) model for detecting sacroiliitis in patients with axSpA using MRI. This study included MRI examinations of patients who underwent semi-coronal MRI scans of the sacroiliac joints owing to chronic back pain with short tau inversion recovery (STIR) sequences between January 2010 and December 2021. Sacroiliitis was defined as a positive MRI finding according to the ASAS classification criteria for axSpA. We developed a two-stage framework. First, the Faster R-CNN network extracted regions of interest (ROIs) to localize the sacroiliac joints. Maximum intensity projection (MIP) of three consecutive slices was used to mimic the reading of two adjacent slices. Second, the VGG-19 network determined the presence of sacroiliitis in localized ROIs. We augmented the positive dataset six-fold. The sacroiliitis classification performance was measured using the sensitivity, specificity, and area under the receiver operating characteristic curve (AUROC). The prediction models were evaluated using three-round three-fold cross-validation. A total of 296 participants with 4,746 MRI slices were included in the study. Sacroiliitis was identified in 864 MRI slices of 119 participants. The mean sensitivity, specificity, and AUROC for the detection of sacroiliitis were 0.725 (95% CI, 0.705-0.745), 0.936 (95% CI, 0.924-0.947), and 0.830 (95%CI, 0.792-0.868), respectively, at the image level and 0.947 (95% CI, 0.912-0.982), 0.691 (95% CI, 0.603-0.779), and 0.816 (95% CI, 0.776-0.856), respectively, at the patient level. In the original model, without using MIP and dataset augmentation, the mean sensitivity, specificity, and AUROC were 0.517 (95% CI, 0.493-0.780), 0.944 (95% CI, 0.933-0.955), and 0.731 (95% CI, 0.681-0.780), respectively, at the image level and 0.806 (95% CI, 0.729-0.883), 0.617 (95% CI, 0.523-0.711), and 0.711 (95% CI, 0.660-0.763), respectively, at the patient level. The performance was improved by MIP techniques and data augmentation. An AI model was developed for the detection of sacroiliitis using MRI, compatible with the ASAS criteria for axSpA, with the potential to aid MRI application in a wider clinical setting.

Comparison of maximum intensity projection and volume rendering on multidetector computed tomography in detecting pulmonary nodules

BackgroundLung cancer is the one of the most common types of cancer and considered as a leading cause of death from neoplasms. Almost all types of lung cancer develop from pulmonary nodules. The wide availability of the multi-detector computed tomography (MDCT) scanners makes the detection of pulmonary nodules much easier. Volume rendering (VR) and maximum intensity projection (MIP) techniques are the most commonly used post-processing techniques. The purpose of this research is to compare and contrast the two techniques in terms of the number and size of nodules.ResultsIn the current study, 32 patients with pulmonary nodules were included being referred from the chest department, with their age ranging from 27 to 71 years old. Nodules characteristics, such as number and size, were evaluated on both MIP and VR techniques. Paired comparison of number of pulmonary nodules less than 6 mm between MIP and VR showed statistically significant difference in 4, 7 and 10 mm slip thickness with P-value 0.003, 0.0001 and 0.0001, respectively. Paired comparison of number of pulmonary nodules more than 6 mm in size between MIP and VR showed no statistically significant difference in 4, 7 and 10 mm slip thickness with P-value > 0.05 each. Comparison of the pulmonary nodules numbers according to slip thickness showed that there was a statistically significant difference in the number of detected nodules, showing that 10 mm slip thickness is significantly higher compared to 4 mm and 7 mm with P-value 0.0001, 0.0001 for nodules < 6 mm, and 0.001 for the lung nodules > 6 mm in size.ConclusionsWe can conclude the superiority of MIP over VR in detection of small sized nodules. MIP was easier to follow and showed high inter-reader agreement. The 10 mm MIP outperformed all other slab thicknesses for nodule detection less than 6 mm. There was no statistically significant difference between both techniques in terms of larger nodules measuring > 6 mm.

Accuracy of multidetector computed tomography with maximum intensity projection technique in the assessment of fissure integrity.

BackgroundBronchoscopic lung volume reduction (BLVR) is a potential treatment for patients with severe emphysema, performed through the placement of unidirectional endobronchial valves (EBVs). Their benefits are only achieved in patients that significantly reduce lobar volume, and it is mandatory that the fissures are complete. Fissure evaluation is preferably done by computed tomography, but little is known if its evaluation corresponds to the anatomical findings. The aim of this study is to evaluate the accuracy of thoracic radiologists in the identification of complete fissures by multidetector computed tomography (MDCT) using maximum intensity projection (MIP) technique, compared with direct anatomical evaluation.MethodsProspective study, conducted in a single institution. Patients submitted to thoracic surgery had their fissures classified as complete or incomplete by thoracic surgeons and their preoperative chest scans evaluated by three radiologists, blinded for surgical evaluation. With the intraoperative categorization as a reference, the accuracy and concordance of the three thoracic radiologists’ evaluation were calculated. The most experienced radiologist evaluated the fissures at two different moments to estimate the intra-observer agreement.ResultsThere were included 67 patients, being 37 (55%) males, with a mean age of 64 years. The accuracy of radiological identification of complete fissures ranged from 76.8% for left posterior oblique fissure to 85.1% for left anterior oblique fissure, with the best performance achieved by the most experienced radiologist. The concordance of the radiological evaluation for fissure integrity compared to the surgical assessment (k) was 0.53–0.68. Intra-observer agreement ranged from 0.74 to 0.87.ConclusionsThe evaluation of the fissure integrity by MDCT analysis using MIP technique by thoracic radiologists had high accuracy among the thoracic radiologists.

Diagnostic Value of Magnetic Resonance Diffusion-Weighted Imaging Combined with Routine Scanning in Body Tumors.

The aim of this study was to evaluate the value of whole body magnetic resonance diffusion-weighted imaging (WB-DWI) combined with routine scanning in the diagnosis of body tumors. Sixty-three patients with surgically and pathologically confirmed body tumors admitted to our hospital from October 2019 to October 2021 were scanned by WB-DWI using a 1.5TMR body coil. The images were reconstructed by a three-dimensional maximum intensity projection (3D-MIP) and black-white inversion technique. The lesions detected by WB-DWI were all plain MRI, and 35 cases were enhanced MRI. The number of lesions detected by WB-DWI and WB-DWI combined with routine scanning and the number of cases matching diagnosis were compared. The WB-DWI images of tumor lesions were analyzed, and the apparent diffusion coefficient (ADC) of the lesions was measured, and the ADC value of benign and malignant lesions was compared. There were 236 lesions in 63 patients with clinically confirmed tumors. 46 cases were diagnosed by WB-DWI, the diagnostic coincidence rate was 73.0%, and 207 lesions were detected. Fifty-eight cases were diagnosed by WB-DWI combined with routine scanning, the diagnostic coincidence rate was 92.1%, 236 lesions were detected. There were statistically significant differences in the number of lesions detected and the coincidence rate of tumor diagnosis between the two groups (P < 0.05). The average ADC value of malignant tumor ((1.04 ± 0.46) × 10−3 mm2/s) was lower than that of benign tumor ((2.53 ± 0.43) × 10−3 mm2/s), and the difference was statistically significant (P < 0.05). In conclusion, MR whole-body diffusion weighted imaging is safe, efficient, radiation-free, and highly sensitive, which is of great significance in the differential diagnosis of benign and malignant lesions. WB-DWI combined with MR routine scanning can further improve the detection rate of lesions and the coincidence rate of tumor diagnosis.

Radiographic optimization of the lateral position of the knee joint aided by CT images and the maximum intensity projection technique

BackgroundStandard lateral knee-joint X-ray images are crucial for the accurate diagnosis and treatment of many knee-joint-related conditions. However, it is difficult to obtain standard lateral knee-joint X-ray images in the current knee-joint lateral radiography position.PurposeTo optimize the lateral position of knee joint for radiography aided by computed tomography (CT) images and the maximum intensity projection technique.Materials and methodsOne hundred cases of anteroposterior and lateral radiographs of knee joints were included. Of these, 50 cases were for lateral radiography in conventional position, and the other 50 cases were for lateral radiography in optimized position. The optimized position was acquired by a retrospective analysis of one hundred cases of knee-joint CT images. The quality of the X-ray images in optimized group was compared with those in conventional group. The data were statistically analyzed using the Mann–Whitney U test.ResultsThere were differences in the optimized position between males and females. The posterior condyles of the femoral epiphysis in optimized group were in perfect superimposition for most patients. However, the ones in conventional group were not. The average quality score of the lateral knee-joint X-ray images in optimized position was 3.76 ± 0.98, which is much higher than the 1.84 ± 1.15 score in conventional position. Moreover, the difference in the average quality score was statistically significant (P < 0.05).ConclusionOptimization of the lateral position of knee joint for radiography is possible with the aid of CT images and the maximum intensity projection technique.

Comparison of Maximum Intensity Projection and Volume Rendering in Detecting Pulmonary Nodules on Multidetector Computed Tomography.

IntroductionLung cancer is the most common cancer overall, and the foremost cause of cancer-related mortality. Almost all lung cancers evolve from pulmonary nodules. As multidetector CT (MDCT) scanners are now widely available, there is an increased rate of detection of pulmonary nodules. It is of utmost importance to evaluate pulmonary nodules to rule out the possibility of neoplastic diseases. With advancements in technology, there are various manual and automatic analytic software providing a wide range of post-processing techniques. Maximum intensity projection (MIP) and volume rendering (VR) techniques have been analyzed previously regarding pulmonary nodules but there is a scarcity of data in terms of low-density nodules. This study aims to delineate the comparison and supremacy of both techniques in terms of low-density nodules.MethodologyThe current prospective study was conducted from June 2019 to June 2020 in the Radiology Department at Dr. Ziauddin Hospital, Karachi. Chest CT scans were performed on 16 slice MDCT (Alexion 16 Multi-slice, Toshiba Medical System Corporation, Houston, TX). A consultant radiologist of six years experience and a postgraduate trainee of three years experience analyzed each patient on a workstation (Vitrea 6.2.0, Vital Images, Minnetonka, MN). SPSS 23.0 (SPSS Inc., Chicago, IL) was incorporated for data analysis. Data were expressed in the median and interquartile range (IQR). Data collected for this study were analyzed using analyzing the median difference in nodule count using Wilcoxon’s signed-rank test. A p-value of <0.05 was considered significant.ResultsAfter informed consent, 236 patients were recruited for the study. MIP outperformed VR in terms of nodule detection and low-density nodules at each evaluated slab thicknesses (p<0.001). A 10-mm MIP was superior to all other techniques in terms of detection of pulmonary nodules and low-density nodules (p<0.001). MIP was also considered an easier technique as there was excellent inter-rater reliability and agreement.ConclusionThis study is robust evidence regarding the supremacy of MIP. MIP outperformed VR on every slab thicknesses. The 10-mm MIP technique was superior to all others evaluated and was recorded to be an easier analyzing technique.

LNCDS: A 2D-3D cascaded CNN approach for lung nodule classification, detection and segmentation

The early detection of lung cancer is attained with the detection of initial stage nodules (3−30mm) which can exorbitantly increase the 5-year survival rate of lung cancer patients. Nodules are very small size circumscribed structures in the lungs and are difficult to detect due to their size. The identification of nodule is also more challenging due to similarly resembling structures like non-nodules that contains features which could make it identifiable as a nodule. Therefore, to deal with these challenging issues, we proposed a novel approach for segmentation, classification and detection of lung nodules from CT scan images. In our proposed method we involve a maximum intensity projection technique as a part of image preprocessing method. We demonstrated our experimentation and proposed SquExUNet segmentation model and 3D-NodNet classification model on publicly available Lung Image Database Consortium – Image Database Resource Initiative (LIDC), LNDb Challenge Dataset and purely independent Indian Lung CT Image Database (ILCID) clinical dataset. We proposed a 2D-3D cascaded CNN strategy for detection of nodule that yields the accurately segmented and classified nodule. Results obtained with proposed method indicates that we have successfully detected and segmented the lung nodules effectively, compared to existing lung nodule detection and segmentation algorithms. We achieved a Dice-Coefficient metrics of 0.80 for segmentation of nodule and 90.01% Sensitivity for nodule detection.

P42.06 Automatic Lung Nodule Detection by a Deep Learning-Based CAD System: The Value of Slab Thickness in the Maximum Intensity Projection Technique

Deep learning techniques have shown good results on automated lung nodule detection. The maximum intensity projection technique (MIP) has been proved that it can improve the performance of nodule detection in the deep learning-based computer-aided detection (DL-CAD) system. But the optimal slab thickness is unknown. To provide better assistance for radiologists, the aim of this study is to investigate the effect of the slab thickness in maximum intensity projections by a DL-CAD system on pulmonary nodule detection in CT scans. The public LIDC-IDRI dataset includes 888 CT scans with 1186 nodules annotated by four radiologists. From those scans, MIP images were reconstructed with slab thicknesses of 5 to 50 mm (at 5 mm intervals) and 3 to 13 mm (at 2 mm intervals). The DL-CAD system was trained separately using MIP images with various slab thicknesses. Based on ten-fold cross-validation, the sensitivity and the F2 score were determined to evaluate the performance of the DL-CAD system for nodule detection. The combination of results from 16 MIP slab thickness settings showed a high sensitivity of 98.0%. The sensitivity increased (82.8% to 90.0%) for slab thickness of 1 to 10 mm and decreased (88.7% to 76.6%) for slab thickness of 15 to 50 mm. The number of false positives (FPs) was decreasing with increasing slab thickness, but was stable at 4 FP/scan at a slab thickness of 30 mm or more. With a MIP slab thickness of 10 mm, the DL-CAD system reached the highest sensitivity of 90.0%, with 8 FPs/scan. The utilization of multi-MIP images could further improve the performance of lung nodule detection in the DL-CAD system. The DL-CAD system showed the highest sensitivity for pulmonary nodule detection based on MIP images of 10 mm, similar to the slab thickness usually applied by radiologists.

Role of CT Imaging With Three-Dimensional Maximum Intensity Projection Reconstruction in the Evaluation of Portal Vein Variants at a Tertiary Care Hospital

Introduction: Portal vein (PV) is the principal blood vessel transporting blood from the alimentary tract and spleen to the liver. The aim of this study is to determine the prevalence of PV anatomical variations in our population using multidetector CT with maximum intensity projection (MIP) technique at a tertiary care hospital.Methods: This cross-sectional study was prospectively conducted from November 2018 to June 2019 in the Department of Radiology at a tertiary care hospital in Karachi. After informed consent, all the patients with no known hepatic pathology undergoing routine abdomen CT were included in this study. Patients with previous hepatic resection surgeries, undiagnosed large hepatic tumors/metastasis, and those with PV thrombosis were excluded.Results: A total of 500 patients (256 males and 244 females) were included in the study; the mean age of female patients was relatively higher as compared to the male patients (53.80 ± 18.44 vs. 44.15 ± 19.94 years; p = 0.000). Standard PV anatomy (type 1) was found in 438 patients (87.6%). Trifurcation (type 2) occurred in 18 patients (3.6%). Right posterior portal vein as the first branch of main PV (type 3) was found in 22 patients (4.4%). A separate branch of the right portal vein (RPV) to segment VII (type 4) and separate branch of the RPV to segment VI (type 5) were found in 6 (1.2%) and 16 (3.2%) patients, respectively.Conclusion: Our study displayed a relatively higher frequency of standard PV anatomy (type 1) compared to previous studies. We highlight the role of MIP in the analysis of hepatic venous anatomy with its utility demonstrating improved detection of variations.

New technique: the use of the THRIVE sequence in the follow-up of patients who received endovascular intracranial aneurysm treatment.

To determine the diagnostic accuracy of 3D time of flight MR angiography (TOF-MRA), contrast enhanced MR angiography (CE-MRA), and T1-weighted high-resolution isotropic volume examination (THRIVE) at 3 T for the evaluation of intracranial aneurysm occlusion after endovascular treatment and to evaluate the usability of the THRIVE sequence in endovascular treatment follow-up. In 3 T MR follow-up examinations of 66 aneurysms in 50 patients treated endovascularly, 3D TOF-MRA (index test), THRIVE (index test), and CE-MRA (reference standard) examinations were performed in a retrospective consecutive case series. Source images were classified as class 1, class 2, and class 3 according to the Raymond criteria using MIP (maximum intensity projection) techniques. The compatibility between sequences was evaluated with the Kappa test. The sensitivity and specificity were also calculated. In the evaluation of THRIVE and CE-MRA sequences, compatibility was determined in 61 cases in total, with an overall fit of 61/66 (92.42%). A statistically significant correlation was found between THRIVE and CE-MRA (p < 0.001, κ = 0.800). In the evaluation of TOF and CE-MRA sequences, compatibility was determined in 54 cases in total, and the overall fit was 54/66 (81.8%). A statistically significant agreement was found between TOF and CE-MRA (p < 0.001, κ = 0.502). Assuming that CE-MRA is a reference standard, the sensitivity and specificity of the TOF sequence were 44.4% and 97.9%, respectively, and the sensitivity and specificity of the THRIVE sequence were 77.8% and 97.9%, respectively. The THRIVE sequence can be used as a noncontrast method for monitoring endovascularly treated intracranial aneurysms.

Maximum intensity projection technique in the identification of small pulmonary nodules

Maximum intensity projection technique in the identification of small pulmonary nodules

Diagnostic importance of maximum intensity projection technique in the identification of small pulmonary nodules with computed tomography

Introduction: In this retrospective study, the aim is to determine the sensitivity of maximum intensity projection (MIP) technique to 3 mm-thick axial sections in patients with small pulmonary nodules identified via examination using computed tomography (CT), and to identify whether this technique provides significant reduction in duration of nodule evaluation. Materials and Methods: A total of 69 patients (339 nodules) who underwent thoracic tomography due to various complaints and in whom pulmonary nodules were identified as a result of the examination were included in the study. Their axial sections that are 3 mm-thick and MIP sections obtained in the axial plane were evaluated by two different radiologists at different times by keeping time. The dimensions and evaluation times of the nodules were recorded separately for each method. Result: Evaluation compatibility between the radiologists was found to be 86.8% and it was considered to be perfectly compatible. Sensitivity of the 1st radiologist in the detection of nodules with MIP was 81.4%, whereas the sensitivity of the 2nd radiologist was 83.4%. In the evaluation for the reporting periods, when the duration of evaluation of MIP images were compared with the gold standard, a statistically significant reduction was found in the reporting times of both radiologists (p< 0.01). Conclusions: It was found that utilization of MIP images as an alternative method to detect pulmonary modules reduces the duration of evaluation significantly and provides the ability to detect nodules with high sensitivity. According to these data, MIP imaging may be preferred as an adjunct method in the evaluation of lung nodules as it provides fast and reliable information besides classical axial sections.

Küçük boyutlu akciğer nodüllerinin bilgisayarlı tomografi ile saptanmasında maksimum intensite projeksiyon tekniğinin önemi

In this retrospective study, the aim is to determine the sensitivity of maximum intensity projection (MIP) technique to 3 mm-thick axial sections in patients with small pulmonary nodules identified via examination using computed tomography (CT), and to identify whether this technique provides significant reduction in duration of nodule evaluation. A total of 69 patients (339 nodules) who underwent thoracic tomography due to various complaints and in whom pulmonary nodules were identified as a result of the examination were included in the study. Their axial sections that are 3 mm-thick and MIP sections obtained in the axial plane were evaluated by two different radiologists at different times by keeping time. The dimensions and evaluation times of the nodules were recorded separately for each method. Evaluation compatibility between the radiologists was found to be 86.8% and it was considered to be perfectly compatible. Sensitivity of the 1st radiologist in the detection of nodules with MIP was 81.4%, whereas the sensitivity of the 2nd radiologist was 83.4%. In the evaluation for the reporting periods, when the duration of evaluation of MIP images were compared with the gold standard, a statistically significant reduction was found in the reporting times of both radiologists (p< 0.01). It was found that utilization of MIP images as an alternative method to detect pulmonary modules reduces the duration of evaluation significantly and provides the ability to detect nodules with high sensitivity. According to these data, MIP imaging may be preferred as an adjunct method in the evaluation of lung nodules as it provides fast and reliable information besides classical axial sections.

Lymphangiography and Post-lymphangiographic Multidetector CT for Preclinical Lymphatic Interventions in a Rabbit Model.

To describe the feasibility of lymphangiography and the visibility of the lymphatic system using post-lymphangiographic multidetector CT (MDCT) for preclinical lymphatic interventions in a rabbit model. Lymphangiography via the popliteal lymph node or vessel after surgical exposure was performed, using six healthy female Japanese White rabbits. Lipiodol was manually injected for lymphangiography. Post-lymphangiographic MDCT examinations were performed in all rabbits. The dataset images were subjected to image processing analysis utilizing the three-dimensional maximum intensity projection technique. Three reviewers evaluated the degree of depiction of the lymphatic system using a four-point visual score (1, poor; 2, fair; 3, good; 4, excellent). The distance between the body surface and cisterna chyli was measured on post-lymphangiographic MDCT axial image. Lymphangiography was successfully performed in all rabbits. The popliteal lymph node was detectable in 90%. The visualization of lymphatic system via the popliteal node was achieved in 89%. Mean visual scores of >3.0 were realized by the right femoral lymphatic vessel, left femoral lymphatic vessel, left iliac lymphatic vessel, left lumbar lymphatic trunks and cisterna chyli, whereas mean visual scores of < 3.0 were yielded by the right iliac lymphatic vessel, right lumbar lymphatic trunks and thoracic duct. The distance between the body surface and cisterna chyli on post-lymphangiographic MDCT axial images was 4.33 ± 0.14cm. Lymphangiography is feasible, and the visibility of the lymphatic system on post-lymphangiographic MDCT in a rabbit model provides enough information for interventional radiologists to perform preclinical lymphatic interventions.

Abstract WP55: Through Thick and Thin: Improved Aspects Grading and Dense Vessel Detection Using Simple Ncct Post-processing

Introduction: Assessing Alberta Stroke Program Early CT Score (ASPECTS) and identifying hyperdense arteries on non-contrast CT (NCCT) are important components of decision-making in acute stroke. Conventional practice uses 5mm averaged slice thickness NCCT for interpretation of these features. We have systematically evaluated several post processing techniques on NCCT to determine if there is improved reliability in identification of ASPECTS and hyperdense artery. Methodology: We assessed four post-processing techniques on NCCT namely (1) 5mm averaged thickness (2) Minimum Intensity Projection (mIP) - 5mm thickness (3) thin slices (0.625mm) and (4) Maximum Intensity Projection (MIP) - 5mm thickness (Figure 1). Three raters (student, fellow and expert) independently assessed 100 NCCT scans from the PRoveIT database. All scans were read at four different times 10-14 days apart. At each time-point the post processing modality was changed and the patient order randomized. Information on side of suspected infarction was provided. Raters were asked to score ASPECTS and identify presence of hyperdense artery at each reading. Inter-rater reliability was assessed using Intra-cluster correlation (ICC) for ASPECTS and weighted kappa (wKap) for hyperdense artery. Results: The highest inter-rater reliability was found with the MIP technique (ICC 0.42; p&lt;0.001), followed by 5 mm average, mIP and thin slice respectively (ICC 0.33, 0.32, 0.20; all p&lt;0.01). Highest agreement for hyperdense vessel detection was noted with thin slice (wKap 0.30; p&lt;0.001) followed by Average, MIPs and mIPs respectively (wKap 0.25, 0.18, 0.13; all p &lt;0.05). Conclusion: The use of MIP images for ASPECTS grading and thin images for hyperdense vessel detection improves reliability on NCCT. These simple processing steps are easily available on any modern scanner and may help improve patient care.

Three-dimensional contrast-enhanced magnetic resonance angiography for anterolateral thigh flap outlining: A retrospective case series of 68 patients.

Flap transfer is increasingly used for repairing limb defects secondary to trauma or tumor, and appropriate preoperative planning plays a critical role. The present study aimed to examine the use of three-dimensional (3D) contrast-enhanced magnetic resonance angiography (CE-MRA) in evaluating the blood supply distribution and perforating branch pattern of anterolateral thigh (ALT) flaps. Bilateral donor lower limbs were scanned in 68 patients (136 limbs) using a Siemens Avanto 1.5 T magnetic resonance imaging scanner with a 3D fast low-angle shot sequence, following the thin-slab maximum intensity projection (TS-MIP) technique. The lateral femoral circumflex artery (LFCA) was visualized in all patients: 101 limbs (101/136, 74.3%) were type I; 20 limbs (20/136, 14.7%) were type II; 3 limbs (3/136, 2.2%) were type III; and 12 limbs (12/136, 8.8%) were type IV. Tertiary branches were identified in 94 limbs (94/136, 69.1%). Donor flaps were outlined according to MRA TS-MIP findings in 4 patients. All flaps survived uneventfully following the transfer. In donor flap outlining, 3D CE-MRA with the TS-MIP technique allowed an accurate, direct visualization of the branching pattern and distribution profile of the LFCA supplying the ALT flap.

Computer-aided diagnosis for estimating the malignancy grade of hepatocellular carcinoma using contrast-enhanced ultrasound: an ROC observer study.

We are developing a computer-aided diagnosis (CAD) system for estimating the malignancy grade of hepatocellular carcinoma (HCC) using contrast-enhanced ultrasound (CEUS). In this study, observers estimated the malignancy grade of HCC with and without the cues provided by CAD. Institutional review board approval was obtained and informed consent was waived. A total of 232 histologically confirmed HCCs were studied: 76 well-differentiated HCC (w-HCC), 133 moderately differentiated HCC (m-HCC), and 23 poorly differentiated HCC (p-HCC). In this observer study, CEUS vascular images acquired using the maximum intensity projection technique were displayed together with static B-mode and Kupffer-phase (defined as 10min after injection) images. Five hepatologists independently assigned confidence ratings for the malignancy grade of each HCC. Each hepatologist first read each case without CAD and then immediately afterwards with CAD. The observers' rating data were evaluated by multireader multicase receiver operating characteristic (ROC) analysis. The overall sensitivity of our CAD system for discrimination between three histological differentiation grades of HCC was 87.5% (203/232). For discrimination between w-HCC and m/p-HCC, the mean area under the ROC curve (AUC) for the five observers was significantly improved from 0.779±0.074 to 0.872±0.090 with CAD (P=0.0069). For discrimination between m-HCC and p-HCC, the mean AUC was also significantly improved from 0.713±0.107 to 0.863±0.101 with CAD (P=0.0321). The use of our CAD system can significantly improve the diagnostic performance of hepatologists in discriminating between three histological differentiation grades of HCC using CEUS.

Analysis of enlarged images using time-of-flight magnetic resonance angiography, computed tomography, and conventional angiography.

This study aimed to assess the accuracy of time-of-flight magnetic resonance angiography, computed tomography, and conventional angiography in depicting the actual length of the blood vessels. Three-dimensional time-of-flight magnetic resonance angiography and computed tomography angiography were performed using a flow phantom model that was 2.11 mm in diameter and had a total area of 0.26 cm(2). After this, volume rendering technique and the maximum intensity projection method as well as two-dimensional digital subtraction angiography and three-dimensional rotational angiography based on conventional angiography were conducted. For three-dimensional time-of-flight magnetic resonance angiography, 8 channel sensitivity encoding (SENSE) head coil for the 3.0 Tesla equipment was used. Fluid was added to the normal saline solution at various rates, such as 11.4, 20.0, 31.4, 40.0, 51.5, 60.0, 71.5, 80.1, 91.5, and 100.1 cm/s using an automatic contrast media injector. Each image was thoroughly examined. After reconstructing the image using the maximum intensity projection method, the length of the conduit in the center of the coronal plane was measured 30 times. After performing computed tomography angiography with the 64-channel CT scanner and 16-channel CT scanner, the images were sent to TeraRecon. Then, the length of the conduit in the center of the coronal plane of each image was measured 30 times after reconstructing the images using volume rendering and maximum intensity projection techniques. For conventional angiography, three-dimensional rotational angiography and two-dimensional digital subtraction angiography were used. Images obtained by three-dimensional rotational angiography were reconstructed and enhanced by 33, 50, and 100 % in the 128 Matrix and the 256 Matrix, respectively on the Xtra Vision workstation. The maximum intensity projection was used for the reconstruction, and the length of the conduit was measured 30 times in the center of the coronal plane of each image. Measurements using the two-dimensional digital subtraction angiography were obtained 30 times in the center of the image. As a result, the lumen length measured by three-dimensional enhanced flow MR angiography images was a minimum of 2.51 ± 0.12 mm when the fluid velocity was 40 cm/s. The images obtained by computed tomography angiography were larger than the actual images obtained by using the test equipment and the reconstruction method. Among the reconstruction methods of three-dimensional rotational angiography, the lumen length in the image reconstructed by 100 % in the 256 matrix was the smallest; 2.76 ± 0.009 mm. In the 128 matrix, as the scope of reconstruction was widened, the length of the vessel was increased by 0.710 units. In the 256 matrix, as the scope of reconstruction was widened, the length of the vessel was decreased by 0.972 units. In two-dimensional digital subtraction angiography, the lumen length in the image was 2.22 ± 0.095 mm. Although this image was magnified similar to the image reconstructed by 100 % in the 256 matrix of three-dimensional rotational angiography (P < 0.05), it was closest to the actual image among the images compared in this study. In conclusion, images obtained by two-dimensional digital subtraction angiography were closer to the actual images compared to the images obtained by other procedures. It can be concluded that vascular images obtained by magnetic resonance angiography, CT angiography, and conventional angiography were larger than the actual images.