3D Reformatting Research Articles

An Augmented Reality Model for Evaluating Traumatic Craniofacial Fractures

Background: Accurate diagnosis and spatial characterization of craniofacial fractures is critical for treatment planning and precise fracture reduction. Since augmented reality (AR) has potential for better diagnostic evaluation than traditional three-dimensional (3D) reformats, we tested whether our accessible mobile-based AR model improves diagnostic accuracy, spatial understanding, and decreases task cognitive load when clinicians evaluate facial fractures. Methods: Clinicians (n = 30) in specialties managing craniofacial trauma assessed a database of mandibular and maxillofacial complex fractures of varying severity using computed-tomography slices supplemented with either traditional 3D reformats (control) or the AR model (experimental), completed diagnostic and spatial characterization tasks, and were evaluated quantitatively and qualitatively on diagnostic accuracy, task cognitive load, and weighted preference for the traditional versus AR model. Results: Most clinicians (83%) preferred the AR model overall. Control and experimental groups had equivalent diagnostic sensitivity and specificity. Less experienced clinicians found the AR model required less effort, was less frustrating, and was preferred for fracture displacement characterization. The AR model had no significant impact on more experienced clinicians. All clinicians found the AR model allowed more intuitive manipulation of the 3D object. Those with less experience preferred the AR model over traditional imaging for diagnostic and educational purposes, whereas more experienced clinicians found that the AR model did not significantly alter their established approach to fracture evaluation. Conclusions: Our mobile-based AR model may be preferable to traditional 3D formats for spatial assessment tasks and decreasing task cognitive load, most notably for less experienced clinicians for whom perioperative practices are less established.

Dual energy CT arthrography in shoulder instability: successful iodine removal with virtual non-contrast images and accurate 3D reformats of the glenoid for assessment of bone loss

ObjectiveTo evaluate the image quality of dual energy CT (DECT) of the shoulder after arthrography and of virtual non-contrast (VNC) 3D reformats of the glenoid and to compare glenoid measurements on VNC 3D reformats and on 2D CTs.Materials and methodsDECT arthrography (80 kV/140 kV) was performed in 42 shoulders of 41 patients with instability using diluted iodinated contrast media (80 mg/ml). VNC images and VNC 3D reformats of the glenoid were calculated using image postprocessing. Dose parameters, CT values of intraarticular iodine and muscle, image contrast (iodine/muscle), and image quality (5-point scale: 1 = worst, 5 = best) were evaluated. Two independent readers assessed glenoid morphology and performed glenoid measurements on 2D and 3D images.ResultsCalculation of VNC images and VNC 3D reformats was successful in 42/42 shoulders (100%). The effective dose was mean 1.95 mSv (± 0.9 mSv). CT values of iodine and muscle were mean 1014.6 HU (± 235.8 HU) and 64.5 HU(± 8.6 HU), respectively, and image contrast was mean 950.2 HU (± 235.5 HU). Quality of cross-sectional images, VNC images, and VNC 3D reformats was rated good (median 4 (4–5), 4 (3–4), 4 (3–5), respectively). Detection of an osseous defect was equal on 2D and 3D images (13/42, P > 0.99) with no difference for measurement of the glenoid diameter with mean 28.3 mm (± 2.8 mm) vs. 28.4 mm (± 2.9 mm) (P = 0.5), width of the glenoid defect with 3.2 mm (± 2.1 mm) vs. 3.1 mm (± 2.3 mm) (P = 0.84), surface area with 638.5 mm2 (± 127 mm2) vs. 640.8 mm2 (± 129.5 mm2) (P = 0.47), and surface area of the defect with 46.6 mm2 (± 44.3 mm2) vs. 47.2 mm2 (± 48.0 mm2) (P = 0.73), respectively.ConclusionDECT shoulder arthrography is feasible and allows successful iodine removal with generation of VNC images and accurate VNC 3D reformats of the glenoid for assessment of bone loss.

Correction of Severe Frontal Bossing with Coronal Brow Lift and Osteoplastic Frontal Sinus Setback Aided by Virtual Surgical Planning: A Case Report

Objective: An 18 year old male with a hypoplastic midface, low anterior hairline, heavy brows and marked frontal bossing presented for evaluation. Laboratory evaluation for acromegaly was negative. He did have impairment of his bilateral visual fields as confirmed by visual field testing by ophthalmology. His nasal radix was also of particular concern to him as it formed a significantly depressed crease between his nasal bridge and his brow. He requested surgical correction of these deformities from both a functional and aesthetic standpoint. Methods: We performed thin-cut CT maxillofacial scanning with 3D reformats and submitted this for virtual surgical planning (VSP). We were able to create a template with which to remove the anterior table of the frontal sinus safely, confidently, and without the aid of a craniotomy. The operation was performed through a preexisting bicoronal incision. The anterior table of the frontal sinus was removed in one piece. His forehead and superior orbits were contoured with a burr. After contouring, the anterior table was fixated in a more recessed position. Nasal radix augmentation was also performed using bone grafting. A coronal brow lift was then performed. Results: The patient’s post-operative course was uneventful. He noted marked improvement in his superior visual fields. He had complete resolution of his nasal radix deformity and his frontal bossing. This was confirmed by thin-cut CT maxillofacial scanning postoperatively. His frontal branches were functionally intact and his hairline was raised to a more appropriate position. Conclusions: Virtual surgical planning allowed us to perform an osteoplastic forehead reduction safely and without older methods such as Caldwell x-rays with coin reference, transillumination, or the bayonet forcep technique. It also allowed us to avoid the use of surgical navigation which can be time consuming and cumbersome. This VSP-based access to the frontal sinus has applications in many aspects of reconstructive cranial surgery as well as aesthetic forehead reductions for patients that do not require a craniotomy.

Advances in Axial Imaging of Peripheral Vascular Disease

Peripheral artery disease (PAD) has become increasingly common in the US patient population and can be a highly symptomatic and significant source of morbidity. When PAD is suspected, the first-line screening study that is obtained is typically a noninvasive evaluation that includes the ankle brachial index (ABI). Following a positive screening study, invasive catheter digital subtraction angiography (DSA) has been historically used to image the peripheral artery system and still remains the gold standard. However, newer developments in axial imaging including computed tomography angiography (CTA) and magnetic resonance angiography (MRA) have in large part supplanted DSA for imaging the peripheral artery system in clinical practice. Benefits of CTA include rapid noninvasive acquisition, wide availability, high spatial resolution, and the ability to generate isotropic datasets on 64-detector row and higher CT scanners, thereby allowing for multiplanar 3D reformatting. Drawbacks of CTA include the exposure to both iodinated contrast and ionizing radiation, although the radiation dose exposure is lower than for DSA, and newer techniques such as using low tube voltage and rapid acquisition times allow for lower contrast doses. The presence of vascular calcification also limits the evaluation of small distal arteries using CTA, although the development of dual-energy CT techniques has significantly addressed this issue. Benefits of MRA include the avoidance of exposure to ionizing radiation and high diagnostic accuracy, while drawbacks include limited availability and increased cost along with the risk of nephrogenic systemic fibrosis that is associated with gadolinium-based contrast agents, although the latter can be mitigated by using newer non-contrast MR angiography techniques. Future technical advances in CT and MR hardware and software and MR pulse sequences will likely lead to the broader applicability and increased accuracy of noninvasive axial imaging in the evaluation of patients with peripheral artery disease.

Computed Tomographic Tenography of Normal Equine Digital Flexor Tendon Sheath: An Ex Vivo Study.

Aim of this study was to document the normal computed tomographic tenography findings of digital flexor tendon sheath. Six ex vivo normal equine forelimbs were used. An axial approach was used to inject 185 mg/mL of iopamidol in a total volume of 60 mL into the digital flexor tendon sheaths. Single-slice helical scans, with 5 mm thickness, spaced every 3 mm, for a pitch of 0.6, and with bone algorithm reconstruction, were performed before and after injections of contrast medium. To obtain better image quality for multiplanar reconstruction and 3D reformatting, postprocessing retroreconstruction was performed to reduce the images to submillimetre thickness. Computed tomographic tenography of digital flexor tendon sheaths could visualize the following main tendon structures for every forelimb in contrast-enhanced images as low densities surrounded by high densities: superficial digital flexor tendon, deep digital flexor tendon, manica flexoria, mesotendons, and synovial recess. Results of this study suggest that computed tomographic tenography can be used with accuracy and sensitivity to evaluate the common disorders of the equine digital flexor tendon sheath and the intrathecal structures.

"Black Bone" MRI: a potential alternative to CT with three-dimensional reconstruction of the craniofacial skeleton in the diagnosis of craniosynostosis.

To determine the potential of novel gradient echo parameters, "Black Bone" MRI as an alternative to CT in the identification of normal and prematurely fused cranial sutures both in 2D and 3D imaging. Thirteen children with a clinical diagnosis of craniosynostosis underwent "Black Bone" MRI in addition to routine cranial CT. "Black Bone" datasets were compared to CT and clinical findings. "Black Bone" imaging was subsequently used to develop 3D reformats of the craniofacial skeleton to enhance further visualisation of the cranial sutures. Patent cranial sutures were consistently identified on "Black Bone" MRI as areas of increased signal intensity. In children with craniosynostosis the affected suture was absent, whilst the remaining patent sutures could be visualised, consistent with CT and clinical findings. Segmentation of the "Black Bone" MRI datasets was successful with both threshold and volume rendering techniques. The cranial sutures, where patent, could be visualised throughout their path. Patent cranial sutures appear as areas of increased signal intensity on "Black Bone" MRI distinct from the cranial bone, demonstrating considerable clinical potential as a non-ionising alternative to CT in the diagnosis of craniosynostosis. • Patent cranial sutures appear hyperintense on "Black Bone" MRI • Prematurely fused cranial sutures are distinct from patent sutures • Minimal soft tissue contrast permits 3D-rendered imaging of the craniofacial skeleton.

MRI of the Pelvis in Women: 3D Versus 2D T2-Weighted Technique

The purpose of this study was to compare triplanar 2D T2-weighted turbo spin-echo MR images with reformatted images from a 3D T2-weighted turbo spin-echo sequence in analogous planes with respect to acquisition time, image quality, artifacts, and lesion detection. Forty-four consecutively enrolled women referred for pelvic MRI participated in the study. The protocol included 2D T2-weighted turbo spin-echo sequences in the axial, coronal, and sagittal planes and a single sagittal 3D T2-weighted turbo spin-echo sequence. The acquisition times of the 2D and 3D sequences were calculated. The sagittal 3D data sets were reformatted at 2-mm slice thickness in each plane and compared with the 2D data sets with respect to image quality, artifacts, and lesion detection. The mean acquisition time for the 3D sequence (419 seconds) was significantly shorter than acquisition time for the 2D sequences in three planes (728 seconds) (p < 0.0001). The readers favored the 3D reformats for cervical contrast (p = 0.005); otherwise, there was no significant difference between the 3D reformats and 2D data sets with regard to image quality and lesion detection. The 3D reformats were preferred with respect to respiratory (p < 0.001) and bowel (p < 0.001) motion. The 3D approach with multiplanar reconstructions is a promising tool for imaging the female pelvis because of time savings without compromise of image quality, the diagnostic information obtained, and the versatility of reconstructing images in any orientation.

Three-dimensional computed tomography angiography in presurgical planning for treatment of infratentorial dural arteriovenous fistulas

Dural arteriovenous fistulas (DAVFs) with pure leptomeningeal drainage may be cured by simple interruption of their venous side. This report illustrates the cases of 3 patients undergoing surgery for fistulas classified as Borden Type III, involving the posterior cranial fossa. Preoperatively, the surgical anatomy of these lesions was investigated with 3D reformatting of multislice CT angiography, in addition to conventional angiography. Reformatted images clarified the surgical anatomy of the malformation. Reconstructing both the osseous and the vascular structures and simulating the surgical orientation allowed localization of the dural takeoff point of the DAVF's drainage, showing its relationship with osseous landmarks. Precise localization of the DAVF's drainage may help in choosing the most direct and effective approach to treat the malformation. The reported cases could be treated with a standard retrosigmoid exposure, avoiding the need for more complex cranial base approaches.

Hyoid Bone Abnormalities in Pierre Robin Patients

Hyoid bone abnormalities have not been previously documented in association with Pierre Robin Sequence. Using three-dimensional (3D) reconstructions of helical computed tomography scans, we examined the hyoid bones of neonates affected with Pierre Robin Sequence and compared them to helical scans of unaffected controls. Severe hyoid bone abnormalities were observed in 7/28 cases, and mild abnormalities in another 16. The presence of severe abnormalities was significantly associated with swallowing dysfunction, while none of the neonates affected with Stickler's syndrome were observed to have severe hyoid abnormalities. The significance of these findings is unknown. Clinicians should be aware of these abnormalities because of the wide availability of 3D reformats.

Prevalence of Right Portal Vein Branching Anomalies

Prevalence of Right Portal Vein Branching AnomaliesAnne M. Covey and Karen T. BrownAudio Available | Share

Clinical usefulness of two-dimensional reformatted and three-dimensionally rendered computerized tomographic images: Literature review and a survey of surgeons' opinions

Purpose: This study compares the usefulness of axial computed tomography (CT) with two-dimensional (2D) reformats and three-dimensionally (3D) rendered CT data in the treatment planning and management of patients. Patients and Methods: Twenty-nine patients who had been studied with CT were grouped into the following four clinical problems: 1) temporomandibular joint assessment (n = 8), 2) growth and development assessment (n = 4), 3) posttrauma and postoperative assessment (n = 13), 4) “other” (n = 4). The clinicians who treated these patients were surveyed for their opinions of the usefulness of CT with and without 2D/3D reformatting. Results: In a majority of the cases within each of the four clinical groups, the clinicians believed that 2D and/or 3D reformatting of the CT data provided additional useful information for patient management. In most of the cases, 3D imaging provided information in addition to that provided by the axial or reformatted 2D images. Conclusion: 2D and 3D CT images can be useful to the clinician in diagnosis and treatment planning. These methods enhance the accuracy of diagnostic decisions and the establishment of appropriate treatment plans.