MyMedR

Fulltext Three-Dimensional Dynamic Subtraction Contrast Enhanced Magnetic Resonance Angiography of the peripheral arteries--an initial experience

Ho CK

Med J Malaysia, 2001 Sep;56(3):313-8.

PMID: 11732076

This is a prospective study with the objective of comparing Three Dimensional (3D) Dynamic Subtraction Contrast Enhanced Magnetic Resonance Angiography (3DDSCEMRA) with Conventional Catheter Arteriography (CCA) as the gold standard, in the diagnosis of peripheral occlusive disease. Three patients scheduled for CCA in this hospital in between September and October 2000 were included in this study. Patients underwent 3DDSCEMRA before proceeding to CCA on the same day. The 3DDSCEMRA reader was blinded to the CCA results. The results showed good correlation in iliofemoral segment and poor correlation in the infrapopliteal segment due to artifacts in 3DDSCEMRA images. 3DDSCEMRA is a new, non-invasive and promising technique in the diagnosis of peripheral occlusive disease.

Matched MeSH terms: Imaging, Three-Dimensional*

An efficient method for the computation of Legendre moments

Yap PT, Paramesran R

IEEE Trans Pattern Anal Mach Intell, 2005 Dec;27(12):1996-2002.

PMID: 16355666

Legendre moments are continuous moments, hence, when applied to discrete-space images, numerical approximation is involved and error occurs. This paper proposes a method to compute the exact values of the moments by mathematically integrating the Legendre polynomials over the corresponding intervals of the image pixels. Experimental results show that the values obtained match those calculated theoretically, and the image reconstructed from these moments have lower error than that of the conventional methods for the same order. Although the same set of exact Legendre moments can be obtained indirectly from the set of geometric moments, the computation time taken is much longer than the proposed method.

Matched MeSH terms: Imaging, Three-Dimensional/methods

Brain white and gray matter anatomy of MRI segmentation based on tissue evaluation

Salih QA, Ramli AR, Mahmud R, Wirza R

MedGenMed, 2005;7(2):1.

PMID: 16369380

Different approaches to gray and white matter measurements in magnetic resonance imaging (MRI) have been studied. For clinical use, the estimated values must be reliable and accurate when, unfortunately, many techniques fail on these criteria in an unrestricted clinical environment. A recent method for tissue clusterization in MRI analysis has the advantage of great simplicity, and it takes the account of partial volume effects. In this study, we will evaluate the intensity of MR sequences known as T1-weighted images in an axial sliced section. Intensity group clustering algorithms are proposed to achieve further diagnosis for brain MRI, which has been hardly studied. Subjective study has been suggested to evaluate the clustering group intensity in order to obtain the best diagnosis as well as better detection for the suspected cases. This technique makes use of image tissue biases of intensity value pixels to provide 2 regions of interest as techniques. Moreover, the original mathematic solution could still be used with a specific set of modern sequences. There are many advantages to generalize the solution, which give far more scope for application and greater accuracy.

Matched MeSH terms: Imaging, Three-Dimensional/methods

Model-based compression for 3D medical images stored in the DICOM format

Logeswaran R, Eswaran C

J Med Syst, 2006 Apr;30(2):133-8.

PMID: 16705998

Many medical examinations involve acquisition of a large series of slice images for 3D reconstruction of the organ of interest. With the paperless hospital concept and telemedicine, there is very heavy utilization of limited electronic storage and transmission bandwidth. This paper proposes model-based compression to reduce the load on such resources, as well as aid diagnosis through the 3D reconstruction of the structures of interest, for images acquired by various modalities, such as MRI, Ultrasound, CT, PET etc. and stored in the DICOM file format. An example implementation for the biliary track in MRCP images is illustrated in the paper. Significant compression gains may be derived from the proposed method, and a suitable mixture of the models and raw images would enhance the patient medical history archives as the models may be stored in the DICOM file format used in most medical archiving systems.

Matched MeSH terms: Imaging, Three-Dimensional*

Medical image compression using 3-D Hartley transform

Shyam Sunder R, Eswaran C, Sriraam N

Comput Biol Med, 2006 Sep;36(9):958-73.

PMID: 16026779

In this paper, 3-D discrete Hartley transform is applied for the compression of two medical modalities, namely, magnetic resonance images and X-ray angiograms and the performance results are compared with those of 3-D discrete cosine and Fourier transforms using the parameters such as PSNR and bit rate. It is shown that the 3-D discrete Hartley transform is better than the other two transforms for magnetic resonance brain images whereas for the X-ray angiograms, the 3-D discrete cosine transform is found to be superior.

Matched MeSH terms: Imaging, Three-Dimensional

Fulltext Craniofacial computed tomography imaging: a review

Rajion, Z.A.

Archives of Orofacial Sciences, 2006;1(1):5-8.

MyJurnal

Imaging is a keystone for the understanding and delivery of craniofacial health care and recent developments have led to many diverse technologies and approaches. This paper reviews new developments in three-dimensional imaging, as well as three-dimensional facial image acquisition. Visualization and convergence of the data from these technologies are also described for construction of patient-specific models.

Matched MeSH terms: Imaging, Three-Dimensional

A visual probe localization and calibration system for cost-effective computer-aided 3D ultrasound

Ali A, Logeswaran R

Comput Biol Med, 2007 Aug;37(8):1141-7.

PMID: 17126314

The 3D ultrasound systems produce much better reproductions than 2D ultrasound, but their prohibitively high cost deprives many less affluent organization this benefit. This paper proposes using the conventional 2D ultrasound equipment readily available in most hospitals, along with a single conventional digital camera, to construct 3D ultrasound images. The proposed system applies computer vision to extract position information of the ultrasound probe while the scanning takes place. The probe, calibrated in order to calculate the offset of the ultrasound scan from the position of the marker attached to it, is used to scan a number of geometrical objects. Using the proposed system, the 3D volumes of the objects were successfully reconstructed. The system was tested in clinical situations where human body parts were scanned. The results presented, and confirmed by medical staff, are very encouraging for cost-effective implementation of computer-aided 3D ultrasound using a simple setup with 2D ultrasound equipment and a conventional digital camera.

Matched MeSH terms: Imaging, Three-Dimensional/economics; Imaging, Three-Dimensional/instrumentation*; Imaging, Three-Dimensional/statistics & numerical data

Implementing cost-effective 3-dimensional ultrasound using visual probe localization

Ali A, Logeswaran R

J Digit Imaging, 2007 Dec;20(4):352-66.

PMID: 17372781

This article proposes a set-up for a 3-dimensional ultrasound system using visual probe localization on the conventional 2-dimensional ultrasound machines readily available in most hospitals. A calibrated digital camera is used for probe-tracking (localization) purposes, whereas ultrasound probe calibration is implemented using a purpose-built phantom. The calibration steps and results are detailed here. The overall system is proven effective in clinical trials through scanning of human organs. Results obtained show successful, accurate 3-dimensional representations using this simple cost-effective set-up.

Matched MeSH terms: Imaging, Three-Dimensional/economics*; Imaging, Three-Dimensional/instrumentation

"Focal" ventricular tachycardia: insights from catheter ablation

Mittal S

Heart Rhythm, 2008 Jun;5(6 Suppl):S64-7.

PMID: 18456205 DOI: 10.1016/j.hrthm.2008.03.023

Catheter ablation has come to play an important therapeutic role in the management of some patients with ventricular arrhythmias. An important advance in catheter ablation of ventricular tachycardia (VT) has been the development of three-dimensional catheter-based mapping systems, which permit identification of the tachycardia circuit and facilitate a strategy for catheter ablation. As a result, patients who suffer from "focal" forms of VT have been identified. This can have implications with respect to underlying arrhythmia mechanism, patient prognosis, and therapeutic strategies. The article reviews some insights learned from catheter ablation of focal forms of VT.

Matched MeSH terms: Imaging, Three-Dimensional

Fulltext Bilateral internal carotid artery hypotrophy in malignant osteopetrosis

Ramli N, Rahmat K, Tan GP

Singapore Med J, 2008 Jul;49(7):e175-7.

PMID: 18695851

Malignant osteopetrosis is associated with petrous carotid canal and internal carotid artery stenosis in the skull base. We present a four-year-old boy with malignant osteopetrosis who developed right frontal lobe infarction as a result of bilateral internal carotid artery hypotrophy.

Matched MeSH terms: Imaging, Three-Dimensional

Experimental determination of optimal force system required for control of anterior tooth movement in sliding mechanics

Sia S, Shibazaki T, Koga Y, Yoshida N

Am J Orthod Dentofacial Orthop, 2009 Jan;135(1):36-41.

PMID: 19121498 DOI: 10.1016/j.ajodo.2007.01.034

This study was designed to determine the optimum vertical height of the retraction force on the power arm that is required for efficient anterior tooth retraction during space closure with sliding mechanics.

Matched MeSH terms: Imaging, Three-Dimensional

Craniofacial obesity in patients with obstructive sleep apnea

Banabilh SM, Suzina AH, Dinsuhaimi S, Samsudin AR, Singh GD

Sleep Breath, 2009 Mar;13(1):19-24.

PMID: 18763003 DOI: 10.1007/s11325-008-0211-9

INTRODUCTION: Obstructive sleep apnea (OSA) and obesity are serious, widespread public health issues.

OBJECTIVE: To localize and quantify geometric morphometric differences in facial soft tissue morphology in adults with and without OSA.

MATERIALS AND METHODS: Eighty adult Malays, consisting of 40 patients with OSA and 40 non-OSA controls, were studied. Both groups were evaluated by the attending physician and through ambulatory sleep studies. 3-D stereophotogrammetry was used to capture facial soft tissues of both groups. The 3-D mean OSA and control facial configurations were computed and subjected to principal components analysis (PCA) and finite-element morphometry (FEM).

RESULTS: The body mass index was significantly greater for the OSA group (32.3 kg/m(2) compared to 24.8 kg/m(2), p < 0.001). The neck circumference was greater for the OSA group (42.7 cm compared to 37.1 cm, p < 0.001). Using PCA, significant differences were found in facial shape between the two groups using the first two principal components, which accounted for 50% of the total shape change (p < 0.05). Using FEM, these differences were localized in the bucco-submandibular regions of the face predominantly, indicating an increase in volume of 7-22% (p < 0.05) for the OSA group.

CONCLUSION: Craniofacial obesity in the bucco-submandibular regions is associated with OSA and may provide valuable screening information for the identification of patients with undiagnosed OSA.

Matched MeSH terms: Imaging, Three-Dimensional

Minimally invasive image-guided removal of retrobulbar intraconal foreign body

Vairavan N, Tajunisah I, Subrayan V, Waran V

Orbit, 2009;28(6):442-3.

PMID: 19929682 DOI: 10.3109/01676830903103365

Surgical approaches are becoming increasingly minimally invasive, without compromising either safety or ease. Penetrating ocular foreign bodies has traditionally been approached either by intraocular or supraorbital access. We successfully attempted a minimally invasive approach to remove a retrobulbar foreign body under computer-assisted image guidance in a 19-year-old man involved in an industrial mishap.

Matched MeSH terms: Imaging, Three-Dimensional

Assessment of 3-D nasal airway morphology in Southeast Asian adults with obstructive sleep apnea using acoustic rhinometry

Banabilh SM, Suzina AH, Mohamad H, Dinsuhaimi S, Samsudin AR, Singh GD

Clin Oral Investig, 2010 Oct;14(5):491-8.

PMID: 19806371 DOI: 10.1007/s00784-009-0342-9

The aim of the present study is to investigate nasal airway morphology in Asian adults with and without obstructive sleep apnea (OSA) using acoustic rhinometry (AR), principal components analysis (PCA), and 3-D finite-element analysis (FEA). One hundred eight adult Malays aged 18-65 years (mean ± SD, 33.2 ± 13.31) underwent clinical examination and limited channel polysomnography, providing 54 patients with OSA and 54 non-OSA controls. The mean minimal cross section area 1 (MCA1) and the mean minimal cross sectional area 2 (MCA2) were obtained from AR for all subjects and subjected to t tests. The OSA and control nasal airways were reconstructed in 3-D and subjected to PCA and FEA. The mean MCA1 and MCA2 using AR were found to be significantly smaller in the OSA group than in the control group (p < 0.001). Comparing the 3-D OSA and control nasal airways using PCA, the first two eigenvalues accounted for 94% of the total shape change, and statistical differences were found (p < 0.05). Similarly, comparing the nasal airways using FEA, the 3-D mean OSA nasal airway was significantly narrower in the OSA group compared to the control group. Specifically, decreases in size of approx. 10-22% were found in the nasal valve/head of inferior turbinate area. In conclusion, differences in nasal airway morphology are present when comparing patients with OSA to controls. These differences need to be recognized as they can improve our understanding of the etiological basis of obstructive sleep apnea and facilitate its subsequent management.

Matched MeSH terms: Imaging, Three-Dimensional/methods*

Analysis of foveal avascular zone in colour fundus images for grading of diabetic retinopathy severity

Ahmad Fadzil M, Ngah NF, George TM, Izhar LI, Nugroho H, Adi Nugroho H

Annu Int Conf IEEE Eng Med Biol Soc, 2010;2010:5632-5.

PMID: 21097305 DOI: 10.1109/IEMBS.2010.5628041

Diabetic retinopathy (DR) is a sight threatening complication due to diabetes mellitus that affects the retina. At present, the classification of DR is based on the International Clinical Diabetic Retinopathy Disease Severity. In this paper, FAZ enlargement with DR progression is investigated to enable a new and an effective grading protocol DR severity in an observational clinical study. The performance of a computerised DR monitoring and grading system that digitally analyses colour fundus image to measure the enlargement of FAZ and grade DR is evaluated. The range of FAZ area is optimised to accurately determine DR severity stage and progression stages using a Gaussian Bayes classifier. The system achieves high accuracies of above 96%, sensitivities higher than 88% and specificities higher than 96%, in grading of DR severity. In particular, high sensitivity (100%), specificity (>98%) and accuracy (99%) values are obtained for No DR (normal) and Severe NPDR/PDR stages. The system performance indicates that the DR system is suitable for early detection of DR and for effective treatment of severe cases.

Matched MeSH terms: Imaging, Three-Dimensional/methods*

Fulltext Facial three dimensional surface imaging: an overview

Al-Khatib, Ali Rajih

Archives of Orofacial Sciences, 2010;5(1):1-8.

MyJurnal

The surface facial imagings have many applications in medical fields. The recent past has seen great advances in three dimensional imaging which include laser scanning or stereophotogrammetry. Here, we reviewed various systems with reference to image acquisition, advantages and disadvantages. Examples of important clinical application with reference to the human face are also discussed. Finally, a 3D imaging system at Universiti Sains Malaysia (USM) is described.

Matched MeSH terms: Imaging, Three-Dimensional

Tooth size and dental arch dimensions: a stereophotogrammetric study in Southeast Asian Malays

Al-Khatib AR, Rajion ZA, Masudi SM, Hassan R, Anderson PJ, Townsend GC

Orthod Craniofac Res, 2011 Nov;14(4):243-53.

PMID: 22008304 DOI: 10.1111/j.1601-6343.2011.01529.x

To investigate tooth size and dental arch dimensions in Malays using a stereophotogrammetric system.

Matched MeSH terms: Imaging, Three-Dimensional/methods

Fulltext Cardiac imaging in valvular heart disease

Choo WS, Steeds RP

Br J Radiol, 2011 Dec;84 Spec No 3:S245-57.

PMID: 22723532 DOI: 10.1259/bjr/54030257

The aim of this article is to provide a perspective on the relative importance and contribution of different imaging modalities in patients with valvular heart disease. Valvular heart disease is increasing in prevalence across Europe, at a time when the clinical ability of physicians to diagnose and assess severity is declining. Increasing reliance is placed on echocardiography, which is the mainstay of cardiac imaging in valvular heart disease. This article outlines the techniques used in this context and their limitations, identifying areas in which dynamic imaging with cardiovascular magnetic resonance and multislice CT are expanding.

Matched MeSH terms: Imaging, Three-Dimensional

A novel shape representation of the dental arch and its applications in some dentistry problems

Rijal OM, Abdullah NA, Isa ZM, Davaei FA, Noor NM, Tawfiq OF

Annu Int Conf IEEE Eng Med Biol Soc, 2011;2011:5092-5.

PMID: 22255484 DOI: 10.1109/IEMBS.2011.6091261

Standardized digital images of maxillary dental casts of 47 subjects were analyzed using MATLAB software whereby the two hamular notches and the incisive papilla defines the Cartesian vertical and horizontal axes, as well as the origin. The angle and length of the midpoints of the anterior teeth, mesiobuccal and distobuccal cusp of the posterior teeth were measured from the origin and denoted as θ(1), …, θ(18) and l(1), …, l(18) respectively. These values were collectively used to represent the shape of each dental cast. Clustering and principal component analyses were employed to find possible groups of dental arches using the above measure of shape. The main result of this study is that the 3 groups of dental arch shape may be represented by the novel feature vector v(k) = (θ(k)(1), l(k)(1), θ(k)(3), l(k)(3), θ(k)(5), l(k)(5), θ(k)(13), l(k)(13)), k = 1, 2, 3. Knowledge of v(k) implies three impression trays should be sufficient in a particular prosthetic dentistry application for Malaysian patients. Further, given that v(k) are accurately measured they may be potential candidates as evidence in specific application of forensic dentistry.

Matched MeSH terms: Imaging, Three-Dimensional/methods*

Diagnostic ability of computed tomography using DentaScan software in endodontics: case reports

Siotia J, Gupta SK, Acharya SR, Saraswathi V

Int J Comput Dent, 2011;14(4):321-34.

PMID: 22324223

Radiographic examination is essential in diagnosis and treatment planning in endodontics. Conventional radiographs depict structures in two dimensions only. The ability to assess the area of interest in three dimensions is advantageous. Computed tomography is an imaging technique which produces three-dimensional images of an object by taking a series of two-dimensional sectional X-ray images. DentaScan is a computed tomography software program that allows the mandible and maxilla to be imaged in three planes: axial, panoramic, and cross-sectional. As computed tomography is used in endodontics, DentaScan can play a wider role in endodontic diagnosis. It provides valuable information in the assessment of the morphology of the root canal, diagnosis of root fractures, internal and external resorptions, pre-operative assessment of anatomic structures etc. The aim of this article is to explore the clinical usefulness of computed tomography and DentaScan in endodontic diagnosis, through a series of four cases of different endodontic problems.

Matched MeSH terms: Imaging, Three-Dimensional/methods*

Displaying publications 1 - 20 of 169 in total