Volume-rendering Technique Research Articles

Age Estimation in Living Adults using 3D Volume Rendered CT Images of the Sternal Plastron and Lower Chest.

Age estimation is commonly of interest in a judicial context. In adults, it is less documented than in children. The aim of this study was to evaluate age estimation in adults using CT images of the sternal plastron with volume rendering technique (VRT). The evaluation criteria are derived from known methods used for age estimation and are applicable in living or dead subjects. The VRT images of 456 patients were analyzed. Two radiologists performed age estimation independently from an anterior view of the plastron. Interobserver agreement and correlation coefficients between each reader's classification and real age were calculated. The interobserver agreement was 0.86, and the correlation coefficients between readers classifications and real age classes were 0.60 and 0.65. Spearman correlation coefficients were, respectively, 0.89, 0.67, and 0.71. Analysis of the plastron using VRT allows age estimation in vivo quickly and with results similar than methods such as Iscan, Suchey-Brooks, and radiographs used to estimate the age of death.

Evaluation of the perforators of the anterior communicating artery (AComA) using routine cerebral 3D rotational angiography

BackgroundDamage to perforating branches of the anterior communicating artery (AComA) is a known complication of surgical or interventional treatment procedures for AComA aneurysm leading to neurologic deficits. In spite of...

Popliteal-to-Dorsalis Pedis In-Situ Small Saphenous Vein Bypass under Planning with Mapping Using Computed Tomography Volume Rendering Technique

The small saphenous vein (SSV) is an important graft in limb salvage surgery. It is frequently translocated for bypass surgery. Sometimes, the use of the SSV as an in-situ graft for posterior tibial artery or peroneal artery reconstruction offers the advantages of reduced vein graft injury and improved patency. Recently, saphenous vein mapping through computed tomography (CT) volume rendering technique offers a great quality view to the surgeon. We experienced a patient in whom a CT image with volume rendering technique revealed an aberrant SSV connected with the great saphenous vein at the medial malleolus level. This case indicates that an aberrant SSV may be successfully used as an in-situ conduit for bypass to the dorsalis pedis artery. Here, we present the case of a popliteal-to-dorsalis pedis in-situ vein bypass using a LeMaitre valvulotome (LeMaitre Vascular Inc., USA) under mapping of the aberrant SSV by CT volume rendering technique.

Hyoid Bone Development: An Assessment Of Optimal CT Scanner Parameters and Three-Dimensional Volume Rendering Techniques.

The hyoid bone anchors and supports the vocal tract. Its complex shape is best studied in three dimensions, but it is difficult to capture on computed tomography (CT) images and three-dimensional volume renderings. The goal of this study was to determine the optimal CT scanning and rendering parameters to accurately measure the growth and developmental anatomy of the hyoid and to determine whether it is feasible and necessary to use these parameters in the measurement of hyoids from in vivo CT scans. Direct linear and volumetric measurements of skeletonized hyoid bone specimens were compared with corresponding CT images to determine the most accurate scanning parameters and three-dimensional rendering techniques. A pilot study was undertaken using in vivo scans from a retrospective CT database to determine feasibility of quantifying hyoid growth. Scanning parameters and rendering technique affected accuracy of measurements. Most linear CT measurements were within 10% of direct measurements; however, volume was overestimated when CT scans were acquired with a slice thickness greater than 1.25 mm. Slice-by-slice thresholding of hyoid images decreased volume overestimation. The pilot study revealed that the linear measurements tested correlate with age. A fine-tuned rendering approach applied to small slice thickness CT scans produces the most accurate measurements of hyoid bones. However, linear measurements can be accurately assessed from in vivo CT scans at a larger slice thickness. Such findings imply that investigation into the growth and development of the hyoid bone, and the vocal tract as a whole, can now be performed using these techniques.

A Comparison of 4D DSA with 2D and 3D DSA in the Analysis of Normal Vascular Structures in a Canine Model

4D DSA allows viewing of 3D DSA as a series of time-resolved volumes of a contrast bolus. There is no comparison of the accuracy of the anatomic information provided by 4D DSA with that available from conventional 2D and 3D DSA. Our purpose was to make this comparison by using a canine model. 2D, 3D, and 4D DSA acquisitions were performed in 5 canines from 3 catheter positions in the common carotid artery yielding 15 2D, 15 3D, and 15 4D datasets. For each territory, 3 vascular segments were chosen for comparison. Images were reviewed by 2 experienced neuroradiologists and were graded by the ability to visualize a segment, its filling direction, and preferred technique. Two visualization modes for 4D DSA were compared (volume-rendering technique and MIP). 4D DSA was preferred in 73.9% of the image sets; 2D, in 22.7%; and 3D, in 3.4%. 4D DSA MIP rendering yielded superior visualization of very small vessel details; the 4D DSA volume-rendering technique offered superior depth and overlap information and better visualization of the surface details of the vasculature. In this study, 4D DSA was preferred over 2D and 3D DSA for analysis of normal vasculature. The ability to provide any view of a vascular territory at any time during passage of a contrast bolus seems likely to reduce the need for many 2D acquisitions during diagnostic and therapeutic procedures. This then potentially translates into a reduction in radiation and contrast dose.

Volume rendering of enigmatic high-amplitude anomalies in southeast Brazil: A workflow to distinguish lithologic features from fluid accumulations

High-quality 3D seismic data are used to extract and isolate high-amplitude anomalies so that fluid-related features, magmatic intrusions, and mass-transport deposits can be interpreted. The use of advanced seismic interpretation tools such as volume rendering and attribute extraction replaces the “traditional” horizon mapping of high-amplitude anomalies. In this work we show that the geometry of anomalies is better constrained when seismic attributes can be imaged and interpreted in three dimensions. Volume-rendering techniques are less laborious, reduce interpretation time, and to a large extent remove interpretation biases. To demonstrate the advantages of our approach, we analyze three types of anomalies in southeast Brazil. In the study area, unconformable “soft-on-hard” anomalies are related to fluid accumulations, whereas igneous sills show signature tabular and concave geometries. We also question the existence of sill-to-sill junctions in the study area, otherwise interpreted by conventional interpretation methods, based on the 3D rendering techniques described. Hence, we theorize that the appearance of the junctions on seismic data from other basins can be a consequence of overlapping sill tips, resulting in the constructive interference of their seismic signals.

Neurovascular study of the trigeminal nerve at 3 t MRI.

This study aimed to show a novel visualization method to investigate neurovascular compression of the trigeminal nerve (TN) using a volume-rendering fusion imaging technique of 3D fast imaging employing steady-state acquisition (3D FIESTA) and coregistered 3D time of flight MR angiography (3D TOF MRA) sequences, which we called "neurovascular study of the trigeminal nerve". We prospectively studied 30 patients with unilateral trigeminal neuralgia (TN) and 50 subjects without symptoms of TN (control group), on a 3 Tesla scanner. All patients were assessed using 3D FIESTA and 3D TOF MRA sequences centered on the pons, as well as a standard brain protocol including axial T1, T2, FLAIR and GRE sequences to exclude other pathologies that could cause TN. Post-contrast T1-weighted sequences were also performed. All cases showing arterial imprinting on the trigeminal nerve (n = 11) were identified on the ipsilateral side of the pain. No significant relationship was found between the presence of an artery in contact with the trigeminal nerve and TN. Eight cases were found showing arterial contact on the ipsilateral side of the pain and five cases of arterial contact on the contralateral side. The fusion imaging technique of 3D FIESTA and 3D TOF MRA sequences, combining the high anatomical detail provided by the 3D FIESTA sequence with the 3D TOF MRA sequence and its capacity to depict arterial structures, results in a tool that enables quick and efficient visualization and assessment of the relationship between the trigeminal nerve and the neighboring vascular structures.

The analysis of the maxillary sinus volumes and the nasal septal deviation in patients with antrochoanal polyps.

The aim of this study was to evaluate the relationship between the maxillary sinus volumes and the nasal septal deviation angles in patients with antrochoanal polyps (ACP). 76 patients who underwent ACP surgery were included in the study. Of those 36 patients who had multislice computed tomography (MSCT) were evaluated to calculate maxillary sinus volume. The records of paranasal MSCT of 36 healthy people without any paranasal sinus diseases or surgery constituted age- and gender-matched healthy controls. Maxillary sinüs volumes and septal deviation angles were calculated using the paranasal MSCT volume-rendering technique. Thirty-six patients in the ACP group were compared with 36 polyp side-matched healthy people. The mean age was 16.6 ± 6.7 years in both groups. Statistically, the mean value of the maxillary sinus volume was significantly higher in the ACP group compared with the ACP side-matched control group (15.1 ± 4.6 versus 12.0 ± 3.5 mm(3)) (p = 0.002). Furthermore, the mean value of the maxillary sinus volume in the non-polyp side (14.2 ± 4.7 mm(3)) was statistically higher in the ACP group compared with the side-matched control group volume (11.9 ± 3.8 mm(3)) (p = 0.024). In addition, Fifty-three of 76 ACP patients had septal deviation. While the septal deviation was on the same side with the ACP in 17 patients, it was on the opposite side in 36 patients. In conclusion, the maxillary sinus volumes increased in ACP patients compared with the healthy control group. Many patients had nasal septal deviation on the opposite side of the ACP.

Relationship between the contrast effects of raw data projection images from three-dimensional digital subtraction angiography and the optimal volume rendering parameters.

Volume rendering (VR) is a technique commonly used for the reconstruction of three-dimensional (3D) digital subtraction angiography (DSA) images, and the rendering parameters greatly affect the characteristics of the 3D image. This study aimed to test whether the optimal VR parameters for 3D DSA could be estimated from the contrast effects in rotational two-dimensional (2D) DSA images acquired using 3D DSA. Simulated blood vessels filled with various concentrations of contrast medium were scanned, and the 3D DSA data sets were reconstructed. The syngo AX vessel analysis software that was able to analyze 3D DSA VR image was used for objective measures. Raw data projection images of the 3D DSA data sets in which the mean diameter was calculated as a true value by the software at nine different thresholds for vessel segmentation were selected. In each image set, five images of all 133 rotational 2D DSA images were selected, and the contrast-enhanced area was extracted using a region-growing algorithm. Mean values and standard deviations of each contrast-enhanced area were calculated, and as the thresholds for vessel segmentation of the software increased by 500 every time, significant differences were observed in the mean values (P < 0.01). This optimal threshold can be applied to the window settings of the VR technique. Therefore, the optimal VR parameters for 3D DSA may be determined by analyzing the contrast effects of the raw data projection images, and user-dependent over- and underestimations of 3D DSA VR images also may be prevented.

Parsons' knob, the bony landmark of the tibial insertion of the anterior cruciate ligament, evaluated by three-dimensional computed tomography

BackgroundIn recent years, highly detailed evaluations have been performed using three-dimensional computed tomography (3D CT). Very small bony ridges, such as Resident's ridge and the lateral bifurcate ridge can be visualised by 3D CT. The purpose of this study was to ascertain whether Parsons' knob, which was recognised as the bony landmark of the anterior cruciate ligament insertion on the tibia, can be visualised by 3D CT, and, if this is possible, to clarify its location and morphology. MethodsOne hundred knees were scanned by CT in this study and 3D models were created using the volume-rendering technique. Parsons' knob was detected on the axial 3D CT view of the tibial plateau. The location of the knob was presented on a grid aligned with the medial-to-lateral and anterior-to-posterior anatomical tibial axes. All measurements were expressed as a percentage of the corresponding maximum dimension. The width and height of Parsons' knob were also measured. ResultsParsons' knob was detected in all 100 knees and was ordinarily found as a ridge that ran obliquely forward from the anterior edge of the medial spine. The knob was located at an average of 22 ± 3.1% of the anterior-to-posterior tibial plateau depth from the anterior edge of the tibia and extended from a mean ± s.d. of 46.9 ± 2.1% to 54 ± 3.6% of the medial-to-lateral tibial plateau width from the medial edge of the tibia. The average width of the knob was 11.5 ± 3.1 mm, and the average height was 1.2 ± 0.3 mm at the most medial portion, 0.2 ± 0.3 mm at the most lateral portion, and 1.2 ± 0.3 mm at the intermediate portion between them. The medial and intermediate portions of the knob were significantly higher than the lateral portion (p < 0.05). ConclusionThe location and morphology of Parsons' knob can be well-visualised using 3D CT.

Imaging spectrum of hemangioma and vascular malformations of the head and neck in children and adolescents.

Vascular lesions of the head and neck region in children constitute an interesting group of lesions that benefit immensely from imaging techniques. Imaging is essential for identification, characterization, and delineation of the extent of lesion and subsequent follow-up. Infantile hemangiomas, which are vascular tumors with a specific evolution pattern, constitute a large majority of these lesions. On the other hand, there are vascular malformations, which are anomalies of the vascular system, consisting of a range of vascular tissues associated with various flow patterns. When diagnosis is clinically evident, imaging should utilize non-radiation techniques and address the issues necessary for management. Timing and interpretation of imaging methods employed in assessing childhood vascular lesion should also take into consideration the natural history so that imaging is performed to address a specific question. This review highlights the typical appearance of a hemangioma and a group of vascular malformations of the head and neck. For descriptive purpose, an attempt has been made to group lesions into specific subsites, with each one having specific clinical significance. Cases included illustrate the spectrum of the disease ranging from classical form in young children to slightly differing manifestations of the disease in adolescents and adults. The illustrations also provide a novel way of presenting image data using volume-rendering techniques of 3D data. Multi-modality team interaction and management strategies of these complex lesions are also emphasized.

An alternative contrast medium for computed tomographic angiography: gadolinium.

Sir: Computed tomography is the mainstay for perforator flap angiographic mapping. There is an increasing foundation of evidence in the literature for the use of computed tomographic angiography in the planning of free flaps, able to guide the surgical approach and improve operative outcomes. Iodinated contrast is the gold standard contrast medium for angiographic imaging. Used in either an oil- or water-soluble form, the radiopaque medium is administered intravenously to improve visibility of the vasculature on radiographic images. However, iodinated contrasts are associated with nephrotoxicity and are strongly contraindicated in patients with poor renal function.1 Magnetic resonance angiography has been suggested for use in such a scenario, when iodinated contrast media are not suitable. However, magnetic resonance angiography is also contraindicated in some settings, particularly where there are implanted metallic devices (such as some breast implants). In these cases, options for high-resolution preoperative imaging are limited. We describe the use of gadolinium as an alternative to iodinated contrast media for use in computed tomographic angiography for preoperative flap imaging. This enables the use of the gold standard modality in patients that otherwise would be unable to undergo imaging with computed tomography. Although this has not been described before, gadolinium has been tested as a contrast medium in computed tomography previously.2,3 Gadolinium, with an atomic number of 64, is a rare earth metal that, because of its paramagnetic properties, is an extremely efficacious contrast agent. In its chelated form, gadolinium has been shown to be considerably less nephrotoxic and allergenic than iodinated contrast compounds1 and is not associated, as previously thought, with any increased risk of the development of nephrogenic systemic fibrosis.4 The use of gadolinium (gadolinium diethylenetriaminepentaacetic acid)-enhanced computed tomographic angiography has been described in aortography and other large vessel angiography. The results have been verified with other forms of imaging and the conclusions have been predominantly positive. Chryssidis et al. describe the use of gadolinium for thoracic aortic aneurysm diagnosis, with vascular enhancement concluded to be sufficient for the confident exclusion of an intimal flap with confirmation of findings by magnetic resonance imaging.5 These findings are consistent across thoracic, abdominal, and cerebral vessel imaging. We have used this imaging in two patients who both required vascular mapping for preoperative flap planning, and who were both unable, for various indications, to receive either iodinated contrast or undergo magnetic resonance imaging. The images below are from a woman presenting for unilateral breast reconstruction, for whom iodinated contrast was contraindicated because of impaired renal function and for whom magnetic resonance imaging was also contraindicated because of her breast expander in situ (Mentor 550 cc Tall height model 354/6313; Mentor Corp., Santa Barbara, Calif.), which is incompatible with magnetic resonance imaging because of a magnetic port. Figures 1 and 2 clearly demonstrate the right lateral thoracic and thoracodorsal arteries, imaged for use in a breast-sharing procedure.Fig. 1: Computed tomographic angiogram, maximum-intensity projection software reconstruction, with gadolinium contrast medium, highlighting opacification of the lateral thoracic artery (blue arrow) and thoracodorsal artery (red arrow).Fig. 2: Computed tomographic angiogram, three-dimensional volume-rendered technique software reconstruction, with gadolinium contrast medium, highlighting opacification of the lateral thoracic artery (blue arrow).In both cases, accurate and relevant angiographic data were gained. Despite these being the first two scans of this type obtained, the contrast injections were able to be timed effectively and gadolinium was shown to be a valuable contrast agent when other forms of scanning are contraindicated. DISCLOSURE The authors declare that there is no source of financial or other support or any financial or professional relationship that might pose a competing interest. There was no source of funding for this article. Phaethon Karagiannis, M.B.B.S. Vachara Niumsawatt, M.B.B.S. Department of Surgery Monash University Monash Medical Centre Clayton, Victoria, Australia Warren M. Rozen, M.B.B.S., M.D., Ph.D. Department of Surgery Monash University Monash Medical Centre Clayton, Victoria, and Department of Surgery School of Medicine and Dentistry James Cook University Clinical School Townsville, Queensland, Australia [email protected]

Multimodal navigation of presurgically implanted subdural electrodes for tailored epilepsy surgery after reoperation using the volume-rendering technique

Question: Implantation of subdural strip, grid or depth electrodes is used routinely in epilepsy surgery to estimate the boundaries of the epileptogenic zone (EZ). As data post-processing, referenciation and 3D-visualization of the electrodes with anatomical structures is challenging especially in patients who undergo reoperation, we investigated the hypothesis if the “volume-rendering technique” can produce reliable and accurate data for multimodal neuronavigation.

Hodgkin's Disease Staging by FDG PET/CT in a Pregnant Woman.

A 26-year-old pregnant woman was referred to our center for scleronodular Hodgkin’s disease (SHD). Due to clinical aggravation, the medical staff decided to perform 18F-FDG positron emission tomography/computed tomography (FDG-PET/CT) at 26 weeks of amenorrhea, with the patient's agreement. In case of advanced stage disease, a medical interruption of pregnancy and aggressive chemotherapy would have been performed [1]. The risk of a mistaged lymphoma appeared greater than the fetal risk of an optimized low-dose PET/CT procedure at this conception age. FDG activity was decreased to 3 MBq/kg and CT parameters locked at 80 kV and 80 mAs without intensity modulation (which could have induced a dose increase due to the larger abdominal attenuation compare to the rest of the body). The calculated fetal dosimetry result was 4.1 mSv from FDG PET and 3.2 mSv from CT [2, 3]. Total fetal irradiation was ten times less than the 100 mSv malformative risk limit described by the International Commission on Radiological Protection [4, 5]. Depending on the FDG PET/CT procedure and fetal age, the fetal estimated dose ranged between 1.01 and 21.9 mGy in the 12 other published cases of FDG PET/CT carried out during pregnancy that we found in the literature (Table ​(Table1)1) [5–11]. Table 1 Other published cases of FDG PET/CT carried out during pregnancy The FDG PET/CT demonstrated a stage IIIA lymphoma (Figs. ​(Figs.11 and ​and2)2) and led to treating the patient with corticotherapy as long as the SHD was free of progression. Fetal ultrasonography follow-up remained normal, and a healthy child was born via caesarean section at 36 weeks of amenorrhea. The patient received chemotherapy the day after delivery. Fig. 1 A: FDG PET/CT fusion MIP (maximum intensity projection) shows intense uptake within lymph nodes on both sides of the diaphragm and the fetal skeleton (white arrow). B, C and D: FDG PET without attenuation correction or coregistered CT. E, F and G: Coregistered ... Fig. 2 FDG PET/CT fused VRT (volume-rendering technique) shows hypermetabolism related to myocardial uptake. There was no other uptake by the fetus, in particular in the brain and kidneys In conclusion, use of FDG PET/CT is conceivable during pregnancy for malignant lymphoma staging on medical decision, with an optimized low-dose protocol and with patient agreement.

Feasibility of MDCT angiography for determination of tumor-feeding vessels in chemoembolization of hepatocellular carcinoma.

To investigate the feasibility and accuracy of multidetector computed tomography (MDCT) angiography for assessment of subsegmental tumor-feeding vessels in transarterial chemoembolization (TACE) of hepatocellular carcinoma (HCC). A total of 23 patients with 36 HCCs who underwent TACE during a 14-month period were enrolled. All patients underwent 3-phase dynamic MDCT within a month before TACE. Arterial phase MDCT images were retrospectively reformatted and analyzed for determination of single subsegmental tumor-feeding vessel using maximum intensity projection (MIP) and volume-rendering technique (VRT). Two radiologists independently assessed and scored the MIP and VRT images using 4-grade visual scores (grade 1, no depiction of tumor-feeding vessel; grade 2, indeterminate tumor-feeding vessel; grade 3, probable tumor-feeding vessel; and grade 4, good depiction of tumor-feeding vessel). The weighted kappa test was used to determine interobserver variability, and Wilcoxon signed rank test was used to differentiate visual scores of each technique. Results of digital subtraction angiography were defined as the criterion standard; therefore, assessment of subsegmental tumor-feeding vessel using MIP or VRT was compared with digital subtraction angiography, and the accuracy of each technique was calculated. Interobserver agreement (weighted kappa, 0.746 on VRT and 0.806 on MIP) was substantial to almost perfect. The visual scores for MIP (mean, 3.64 for reviewer 1 and 3.5 for reviewer 2) were higher than those for VRT (mean, 2.11 for reviewer 1 and 2.22 for reviewer 2; P = 0.000). The accuracy for assessing subsegmental tumor-feeding vessel was 22.2% for VRT and 77.8% for MIP. Multidetector CT angiography using MIP showed good imaging quality and high accuracy for determination of subsegmental tumor-feeding vessels.

Left Internal Mammary Artery Graft-to-Pulmonary Artery Fistula

An 80-year-old man was admitted to our hospital because of an acute coronary syndrome. He had undergone coronary artery bypass grafting (CABG) 12 years ago, which involved a left internal mammary artery (LIMA) graft to the left anterior descending coronary artery. Direct LIMA injection revealed an arteriovenous fistula between the distal portion of a grossly dilated LIMA graft and the pulmonary vasculature (Panel A). Cardiac computed tomographic angiography (Panels B, C) and volume-rendering technique (Panels D, E, F) revealed an arteriovenous fistula between LIMA and the pulmonary artery.

模擬大腸ファントムを用いたCTコロノグラフィの画像評価～再構成スライス厚が及ぼす影響について～

Computed tomography colonography (CTC) is a robust and reliable imaging test of the colon. Recent studies show good sensitivity for the identification of nonpolypoid (flat) lesions as well. The purpose of this study was to determine the accuracy and reproducibility of a volume-rendering (VR) and virtual gross pathology (VGP) technique for detecting a polypoid lesion phantom by varying slice thickness. The scan of a simulated house-made phantom was performed using a 16-slice CT scanner with varying combinations of tube voltage (120 kVp), effective exposure (100 mAs), detector configuration (16×0.75 mm), rotation time (0.75 s), helical pitch (0.688, 0.938, 1.066 and 1.188), reconstruction kernel (A, B and C), and section thickness/reconstruction interval (0.8/0.4, 1.0/0.5 and 1.5/0.75 mm). All image data were transferred to a three-dimensional workstation to assess multi-planar reformation (MPR), VR and VGP. Accuracy of volume measurement using the VR technique for quantitative analysis was compared using a paired t-test. Four radiological technologists also independently evaluated the visual score using the VGP technique for qualitative analysis, and their evaluations were compared using one-way analysis of variance with Fisher's protected least significant difference post-hoc test. There was a statistically significant difference in reproducibility between the three different slice thicknesses as to volume measurement and observer performance test (p<0.01 and p<0.05, respectively). Furthermore, the reproducibility improved when using thinner slices. In conclusion, VR and VGP techniques using a slice thickness of 0.8 mm made it possible to maintain accuracy and reproducibility when using CTC to detect polypoid lesions.

Multidetector-row computed tomography in the preoperative diagnosis of intestinal complications caused by clinically unsuspected ingested dietary foreign bodies: a case series emphasizing the use of volume rendering techniques

Objective The present study was aimed at describing a case series where a preoperative diagnosis of intestinal complications secondary to accidentally ingested dietary foreign bodies was made by multidetector-row computed tomography (MDCT), with emphasis on complementary findings yielded by volume rendering techniques (VRT) and curved multiplanar reconstructions (MPR). Materials and Methods The authors retrospectively assessed five patients with surgically confirmed intestinal complications (perforation and /or obstruction) secondary to unsuspected ingested dietary foreign bodies, consecutively assisted in their institution between 2010 and 2012. Demographic, clinical, laboratory and radiological data were analyzed. VRT and curved MPR were subsequently performed. Results Preoperative diagnosis of intestinal complications was originally performed in all cases. In one case the presence of a foreign body was not initially identified as the causal factor, and the use of complementary techniques facilitated its retrospective identification. In all cases these tools allowed a better depiction of the entire foreign bodies on a single image section, contributing to the assessment of their morphology. Conclusion Although the use of complementary techniques has not had a direct impact on diagnostic performance in most cases of this series, they may provide a better depiction of foreign bodies' morphology on a single image section.

Horse-shoe lung-rediscovered via volume rendered images

Horseshoe lung, usually associated with pulmonary venolobar syndrome, is a rare congenital anomaly involving the fusion of the postero-basal segments of the right and left lungs across the midline. The fused segment or the isthmus lies posterior to the pericardium and anterior to the aorta. The associated pulmonary venolobar syndrome involves anomalous systemic arterial supply and anomlaous systemic venous drainage of the right lung. With the advent of MDCT imaging, we can diagnose this rare condition as well all its associated anomalies non-invasively. Volume-rendered techniques greatly simplify the complex anatomy and provide easy understanding of the same.

The preliminary exploration of 64-slice volume computed tomography in the accurate measurement of pleural effusion

Using computed tomography (CT) to rapidly and accurately quantify pleural effusion volume benefits medical and scientific research. However, the precise volume of pleural effusions still involves many challenges and currently does not have a recognized accurate measuring. To explore the feasibility of using 64-slice CT volume-rendering technology to accurately measure pleural fluid volume and to then analyze the correlation between the volume of the free pleural effusion and the different diameters of the pleural effusion. The 64-slice CT volume-rendering technique was used to measure and analyze three parts. First, the fluid volume of a self-made thoracic model was measured and compared with the actual injected volume. Second, the pleural effusion volume was measured before and after pleural fluid drainage in 25 patients, and the volume reduction was compared with the actual volume of the liquid extract. Finally, the free pleural effusion volume was measured in 26 patients to analyze the correlation between it and the diameter of the effusion, which was then used to calculate the regression equation. After using the 64-slice CT volume-rendering technique to measure the fluid volume of the self-made thoracic model, the results were compared with the actual injection volume. No significant differences were found, P = 0.836. For the 25 patients with drained pleural effusions, the comparison of the reduction volume with the actual volume of the liquid extract revealed no significant differences, P = 0.989. The following linear regression equation was used to compare the pleural effusion volume (V) (measured by the CT volume-rendering technique) with the pleural effusion greatest depth (d): V = 158.16 × d - 116.01 (r = 0.91, P = 0.000). The following linear regression was used to compare the volume with the product of the pleural effusion diameters (l × h × d): V = 0.56 × (l × h × d) + 39.44 (r = 0.92, P = 0.000). The 64-slice CT volume-rendering technique can accurately measure the volume in pleural effusion patients, and a linear regression equation can be used to estimate the volume of the free pleural effusion.