Intracranial aneurysm: inner view and neck identification with CT angiography virtual endoscopy

Clinical application of magnetic resonance sialographic 3-dimensional reconstruction imaging and magnetic resonance virtual endoscopy for salivary gland duct analysis

PURPOSE

In a previous study, we showed that the new and fast sequence 3-dimensional (3D)-fast asymmetric spin-echo sequencing could be applied in magnetic resonance (MR) sialographic 3D reconstruction imaging of the parotid gland ducts and in producing virtual endoscopic views of the parotid gland with MR data.

MATERIALS AND METHODS

In the present study, we examined the clinical application of these MR sialographic 3D reconstruction imaging and virtual endoscopy of the salivary gland ducts using MR data sets with 3D-fast asymmetric spin-echo sequencing.

RESULTS

The MR sialographic 3D reconstruction images showed a complete view in the branch paths from all angles, and the MR virtual endoscopic views showed conditions in the endoluminal tracts of the large branches in 20 patients with salivary gland duct abnormalities, including Sjögren syndrome, cyst, tumor, sialadenitis, and salivary calculi.

CONCLUSION

The clinical use of MR sialographic 3D reconstruction imaging and MR virtual endoscopy for salivary gland ducts may enhance understanding of the 3D relationship between the ducts and the surrounding tissue, as well as the endoluminal circumstance within ducts. Possible future applications abound, and further investigation in this field is expected.

Virtual endoscopic view of salivary gland ducts using MR sialography data from three dimension fast asymmetric spin-echo (3D-FASE) sequences: a preliminary study

OBJECTIVES

We performed magnetic resonance (MR) sialography of parotid gland and/or submandibular gland ducts using three-dimensional fast asymmetric spin-echo (3D-FASE) sequencing. The objective was to make three-dimensional (3D) reconstruction images and virtual endoscopic views of the parotid gland ducts using MR sialography data sets of 3D-FASE sequences.

METHODS

We reviewed the MR sialography data sets with 3D-FASE sequencing of 10 control volunteers and six patients. Three-dimensional reconstruction images and virtual endoscopic views of the parotid gland and/or submandibular gland ducts were generated with maximum intensity projection (MIP), shaded surface display (SSD), and volume rendering techniques (VRT).

RESULTS

The main parotid gland and/or submandibular gland ducts, large branches within the glands, and small branches were fairly well defined in a very short acquisition time on MR sialographic images with 3D-FASE sequencing in nine of the 10 healthy volunteers. The 3D-reconstruction images of the parotid gland ducts and/or submandibular gland ducts showed the entire length of the branch paths and complete images from all angles, and the virtual endoscopic views showed the endoluminal tracts of the main ducts and the large branches in nine. In the patient with Sjogren's syndrome, chronic sialoadenitis, and salivary calculi in the Wharton ducts, the MR sialographic images showed diffuse areas of punctate high signal intensity, dilatation of Stensen's duct, or stones of Wharton's duct, respectively. Furthermore, the 3D-reconstruction images of the salivary gland ducts showed the stenoses and stones in the branch paths and complete images from all angles, and the virtual endoscopic views showed the stenoses and stones in the endoluminal tracts of the main and large branches.

CONCLUSIONS

Our initial experience showed that virtual MR endoscopy could be performed to observe the endoluminal tracts of parotid and submandibular glands. The clinical use of the virtual MR endoscopy for salivary gland ducts has not been established yet. Future applications of the 3D-reconstruction images and virtual endoscopic views using MR sialography data sets of 3D-FASE sequences are very attractive and further expansion of this field is expected.

Transluminal imaging with perspective volume rendering of computed tomographic angiography for the delineation of cerebral aneurysms

Transluminal imaging with perspective volume rendering of computed tomographic angiography was used to investigate three patients with unruptured cerebral aneurysms. Selective changes in the opacity chart of computed tomography values, based on a spiked peak curve, represented the contour of the vessel and aneurysmal walls as a series of rings, and allowed a transluminal view from outside or inside the vessel lumen through the spaces between the rings. This imaging technique provided direct visualization of the underlying structures and an extensive perspective view of the cerebral aneurysms, including the parent arteries and surrounding bony structures, through the overlying vessel and aneurysmal walls. Transluminal imaging may be a useful method for the extra- and intraluminal diagnosis of a cerebral aneurysm, and for simulation of the interventional and surgical procedures considered for cerebral aneurysms.

Virtual endoscopy

Virtual endoscopy is a technique in which three-dimensional viewing of hollow structures is conducted through the utilization of high-resolution imaging and unique computer processing methods. The basic components of this technique and its applications for urology and other clinical disciplines are reviewed.

Intracranial aneurysm on CTA: demonstration using a transparency volume-rendering technique

We report an interesting transparency study using a volume-rendering technique applied to CT angiography in a patient with a sylvian aneurysm. On a single view, all the information required for the aneurysmal treatment could be analyzed. Comparison with maximum intensity projection and virtual endoscopy reconstructions was performed.

Virtual endoscopic environments in modern neurosurgical practice

Modern radiographic techniques have allowed the creation of high-definition planar images that can provide important anatomical as well as physiological data. Planar imaging sets can be reformatted into three-dimensional (3-D) data sets that can then be manipulated to demonstrate important anatomical or gross pathological features. Three-dimensional data sets have been used with success in modern image-guided or frameless stereotactic surgery. Another potential application is so-called "virtual endoscopy" or "scopeless endoscopy," in which a 3-D anatomical data set is reformatted into a volume-rendered image that can then be viewed. By reformatting images in this way, a "surgeon's-eye" view can be obtained, which can aid in presurgical planning and diagnosis. The use of virtual endoscopy has the potential to increase our understanding of the appropriate anatomy and the anatomical relationships most apparent during neurosurgical approaches. In so doing, virtual endoscopy may serve as an important means of planning for therapeutic interventions.

On the other hand, one must always be cognizant of the technical limitations of these studies regardless of the quality of the reconstructed images. Prospective, correlative, clinical studies in which the anatomical advantages of virtual-based endoscopy are evaluated in large cadaver or patient series must be performed. Until then, the only potential ways to compensate for errors that exist in the algorithms and reconstructions of 3-D endoscopic images are based on the surgeon's understanding of the clinical state of the patient and prior experience with the anatomy in the region of question.

MR virtual endoscopy of the pancreaticobiliary tract

PURPOSE

To evaluate the feasibility of surface-rendered magnetic resonance virtual endoscopy (MRVE) of magnetic resonance cholangiopancreatography (MRCP) data sets. We retrospectively reviewed MR cholangiopancreatography data sets of 120 patients with biliary stone (n=40), inflammatory ampullary stenosis (n=12), pancreatic tumor (n=8), cholangiocarcinoma (n=7), stenosis of surgical bilio-enteric anastomosis (n=4), extrinsic localized common bile duct stenosis (n=2), ampullary carcinoma (n=2), pancreatic duct stone (n=1), tumor of the gallbladder (n=1), and normal pancreaticobiliary tree (n=43). MRVE views were generated with Navigator software. Segmentation of the acquired data sets was performed with a thresholding technique. Navigation sequences were simulated through the entire biliary tract. MRVE was obtained in 27 (63%) of the 43 normal patients. Endoscopic views were generated in all 77 patients with partial or complete obstruction of the pancreaticobiliary tree. Among these, three groups of patterns were identified: 36 (47%) endoluminal masses (polyp-like masses), 17 (22%) luminal stenoses, 24 (31%) luminal occlusion. In 29 cases, hole artifacts through the internal wall were observed and interpreted as mistakes of segmentation. MRVE proved to show the internal anatomy of the biliary tract and endoluminal changes due to pathological condition. Further investigations are needed to test the usefulness and the potentialities of this technique.