Mohammad al-Shatouri

Sparsity-constrained three-dimensional image reconstruction for C-arm angiography

X-ray C-arm is an important imaging tool in interventional radiology, road-mapping and radiation therapy because it provides accurate descriptions of vascular anatomy and therapeutic end point. In common interventional radiology, the C-arm scanner produces a set of two-dimensional (2D) X-ray projection data obtained with a detector by rotating the scanner gantry around the patient. Unlike conventional fluoroscopic imaging, three-dimensional (3D) C-arm computed tomography (CT) provides more accurate cross-sectional images, which are helpful for therapy planning, guidance and evaluation in interventional radiology. However, 3D vascular imaging using the conventional C-arm fluoroscopy encounters some geometry challenges. Inspired by the theory of compressed sensing, we developed an image reconstruction algorithm for conventional angiography C-arm scanners. The main challenge in this image reconstruction problem is the projection data limitations. We consider a small number of views acquired from a short rotation orbit with offset scan geometry. The proposed method, called sparsity-constrained angiography (SCAN), is developed using the alternating direction method of multipliers, and the results obtained from simulated and real data are encouraging. SCAN algorithm provides a framework to generate 3D vascular images using the conventional C-arm scanners in lower cost than conventional 3D imaging scanners.

Three-dimensional angiography using mobile C-arm with IMU sensor attached: Initial study

Three-dimensional (3D) computed tomography (CT) imaging is becoming an essential demand in several clinical procedures. Mobile C-arm is a useful imaging tool for image-guided interventional radiology. C-arm systems are provided with X-ray image intensifier (XRII) or flat-panel detectors. Essentially, C-arm CT systems requires scanners with flat-panel detectors for its ability to provide homogenous image quality and improve the resolution of low-contrast subjects compared to those equipped with XRII. However, C-arm systems with XRIIs are widely used in several interventional procedures. Such systems can provide a high quality two-dimensional (2D) fluoroscopic images that facilitates minimal invasive surgery. However, it is unable to provide depth information for 3D imaging due to several factors. First, the gantry of XRII-based C-arms is usually operated manually, where the rotation angle is determined using printed angle scale attached to the scanner gantry. Second, the gantry orbital rotation is normally limited to angular range less than theoretically required for exact 3D reconstruction. Third, considering the offset-scan geometry, which is common configuration in mobile C-arm with XRII, the number of rays passing through field-of-view (FOV) is limited. In this paper, we develop a 3D angiographic imaging system using commercial C-arm system equipped with XRII. First, an in-house made gantry rotation unit is developed to control the scanner orbital rotation. Second, the gantry rotation is traced using inertial measurement unit (IMU) sensor attached to the scanner gantry. Geometry information obtained from IMU sensor are used to define the gantry position in the 3D space and synchronized with detector measurements. The SCAN algorithm is used for the 3D reconstruction and achieved results are of high quality.

Efficacy of therapeutic fluoroscopy-guided lumbar spine interventional procedures.

PURPOSE To evaluate the benefit of fluoroscopy-guided lumbar spine interventional procedures in treatment of low back pain. METHODS This prospective descriptive study was performed on 60 patients with back/radicular pain after showing no improvement with conservative treatment. RESULTS One hundred and two injection sessions were done (average 1.7 injection per patient). Caudal and lumbar transforaminal injections were effective in 55.9% and 78.5%, respectively. Facet and sacroiliac interventions were effective in 28.3% and 10%, respectively. Complications occurred in 20% of the procedures. CONCLUSION Lumbar injections improved pain/disability related to discogenic lumbar spinal diseases. Efficacy of facet and sacroiliac injections is limited.

Computer Aided Diagnosis System for Liver Cirrhosis Based on Ultrasound Images

This work introduces a computer-aided diagnosis (CAD) system for diagnosing liver cirrhosis in ultrasound (US) images. The proposed system uses a set of features obtained from different feature extraction methods. These features are the first order statistics (FOS), the fractal dimension (FD), the gray level co-occurrence matrix (GLCM), the Gabor filter (GF), the wavelet (WT) and the curvelet (CT) features. The measured features are presented in two different classifiers such as support vector machine (SVM) and k-nearest neighbors (K-NN). The proposed system is applied on dataset consists of 72 cirrhosis and 75 normal regions each of 128x128 pixels. The classification accuracy rates are calculated using a 10-fold cross validation. A correlation-based feature selection (CFS) is used resulting in better accuracy predictions. The results showed that SVM and K-NN classifiers achieved higher performance with the combination of the wavelet and curvelet feature vectors than other feature extraction methods.

Needle detection in interventional pain management with 3D image reconstruction

Interventional pain management surgery is a clinical application performed though the guidance of x-ray fluoroscopy. Several protocols requires the injection of a needle close to the spinal cord to deliver a medication directly to the nerve system. The needle position information in the 3D space is important to avoid possible damage to the nerve system. It is common to perform the pain management surgery using C-arm scanner to follow up the treatment procedure. In many cases, it is difficult to observe the exact position of the injected needle through 2D images acquired using conventional C-arm scanner especially with complicated bone structures. It requires several attempts to image the patient from different positions and physician requires a mental process to imagine how the 3D structure looks like before starting the interventional procedure. This process may be repeated several times during a single interventional session, which cause a significant increase of radiation dose given to both patient and surgeon. In this paper, we introduce a method for needle detection in interventional pain management surgery using a clinical C-arm scanner. First, an in-house made gantry control unit (GCU) is mounted to the C-arm gantry to control the scanner orbital rotation. Second, the gantry rotation is traced using inertial measurement unit (IMU) sensor attached. A single cine loop is acquired by automatically rotate the C-arm gantry around the patient using GCU. Geometry information obtained from the IMU sensor is used to define the gantry position in the 3D space and synchronized with detector measurements in cine loop frames. The SCAN algorithm is then adopted for the 3D reconstruction of bone structures and injected needle.

Compressed-sensing-based three-dimensional image reconstruction algorithm for C-arm vascular imaging

X-ray C-arm is an important imaging tool in interventional surgery, road-mapping and radiation therapy. It provides accurate description of vascular anatomy and therapy end point. The C-arm scanner produces two-dimensional (2D) x-ray projection data obtained with flat-panel detector by rotating the source around the patient. The number of 2D projections acquired is several hundreds, which results in significant amount of radiation dose. Unlike the conventional fluoroscopic imaging, three-dimensional (3D) C-arm computed tomography (CT) provides more accurate cross-sectional images which are valuable for therapy planning, guidance and evaluation in interventional radiology. However, 3D vascular imaging using the conventional C-arm fluoroscopy is a challenging task. First, the rotation orbit of the C-arm gantry is usually limited to a range less than those of CT scanners. Second, in several commercial models (including the one of consideration in this study), the x-ray source and detector are shifted from the gantry isocenter to enlarge the scanner field-of-view (FOV), which is so-called the offset scan. Finally, it is difficult to acquire sufficient projection views required for stable 3D reconstruction using manually controlled gantry motion. Inspired by the theory of compressed sensing, we developed an image reconstruction algorithm for the conventional angiography C-arm scanners. The main challenge in this image reconstruction problem is the projection data limitations. We consider a small number of views (less than 10 views) acquired from a short orbit with the offset scan geometry. The proposed method is developed using the alternating direction method of multipliers (ADMM) and results obtained from simulated data and real data are encouraging. The proposed method can significantly contribute to the reduction of patient dose and provides a framework to generate 3D vascular images using the conventional C-arm scanners.

Development of interactive 3D imaging system for hepatic angiography

Egypt is witnessing over the next decade many challenges in the field of healthcare, especially with regard to the spread of hepatitis and coincides with the spread of liver hepatocellular carcinoma. Because most cases of liver cancer in Egypt are detected in very late stages, the use of surgical resection, liver transplantation and percutaneous ablative therapies constitutes unsuitable therapeutic options either due to high recurrence rate or unfeasibility. Therapy sessions can be made through the introduction of chemotherapy using a catheter directly into the hepatic artery supplying the tumor guided by angiography imaging system. This method of treatment known to prevent the patient from different problems associated with surgical treatment, but it is still needs to be further improved to maximize the benefits and minimize the risks. Hepatic angiography is an x-ray study of the blood vessels that supply the liver. The procedure uses a catheter that is placed into a blood vessel through a small incision. The catheter is guided using the x-ray images obtained through the interventional session. During angiography, hepatic arterial supply is usually displayed in one, two or three projections. Mental 3D interpretation of the anatomy is not an easy task. Reaching the target supply artery by the catheter tip is mandatory to obtain satisfactory tumor response and reduce complications and recurrence. This work aims to develop an interactive 3D imaging system of hepatic angiography. The developed system uses a set of 2D images measured over few view angles to reconstruct a full 3D volume of the hepatic arteries. The problem can be thought as a combination of three main approaches. (1) Image reconstruction of 3D artery volume from few number of projections (each is presented as 2D image), (2) automatic detection of the catheter roadmap to the labeled artery which feed the tumor, and (3) interactive system to control and display images using simple gestures of the physician.