The pattern of prostate cancer local recurrence after radiation and salvage cryoablation.

Objective: We assessed the pattern of local recurrence after salvage cryoablation of the prostate, and the impact of local recurrence on intermediate-term outcome.

Methods: One hundred twenty-two patients who underwent salvage cryoablation were studied after a mean follow-up of 56 months. Serial prostate biopsy was carried out after cryoablation.

Contemporary technique of intraoperative 3-dimensional ultrasonography-guided transperineal prostate cryotherapy.

Successful cryotherapy of the prostate for neoplasms relies on imaging to achieve good oncological outcomes with minimal complications. Traditional prostatic cryotherapy relies on 2-dimensional ultrasonography (2DUS) guidance, which often makes it difficult to track the passage of needles in an oblique plane. We describe our initial 3-dimensional ultrasonography (3DUS) system, and the subsequent improvements that have been made during the last 10 years.

Fast prostate segmentation in 3D TRUS images based on continuity constraint using an autoregressive model.

In this article a new slice-based 3D prostate segmentation method based on a continuity constraint, implemented as an autoregressive (AR) model is described. In order to decrease the propagated segmentation error produced by the slice-based 3D segmentation method, a continuity constraint was imposed in the prostate segmentation algorithm. A 3D ultrasound image was segmented using the slice-based segmentation method.

Salvage cryoablation of the prostate: followup and analysis of predictive factors for outcome.

Purpose: We assessed the efficacy of cryoablation of the prostate with an emphasis on finding predictive factors that lead to improved outcome.

Materials And Methods: A total of 187 patients with locally recurrent prostate cancer after radiotherapy underwent salvage cryoablation of the prostate, and were studied after a mean followup of 39 months. Survival analysis was performed with the Kaplan-Meier method.

Prostate boundary segmentation from ultrasound images using 2D active shape models: optimisation and extension to 3D.

Boundary outlining, or segmentation, of the prostate is an important task in diagnosis and treatment planning for prostate cancer. This paper describes an algorithm based on two-dimensional (2D) active shape models (ASM) for semi-automatic segmentation of the prostate boundary from ultrasound images. Optimisation of the 2D ASM for prostatic ultrasound was done first by examining ASM construction and image search parameters.

Needle and seed segmentation in intra-operative 3D ultrasound-guided prostate brachytherapy.

In order to guide the needle to the correct location in 3D US-guided brachytherapy, the needle is continuously tracked as it is being inserted. A pre-scan before the needle insertion and a post-scan after the needle insertion are subtracted to obtain a difference image containing the needle. The image is projected along two orthogonal directions approximately perpendicular to the needle, and the 3D needle is reconstructed from the segmented needles in the two projected images.

High-frequency ultrasound: a useful tool for evaluating the abdominal wall following free TRAM and DIEP flap surgery.

Background: This is the first study to use a standardized ultrasound protocol to evaluate hernia and abdominal wall laxity following free transverse rectus abdominis myocutaneous (TRAM) and deep inferior epigastric perforator (DIEP) flap surgery.

Methods: All patients who underwent free TRAM and DIEP flap surgery performed by the senior author between the years 1994 and 2003 were recruited for physical examination and ultrasound of the abdominal wall for the dynamic evaluation of hernia and abdominal wall laxity.

Results: A total of 25 of 28 patients were followed up (89 percent).

Oblique needle segmentation and tracking for 3D TRUS guided prostate brachytherapy.

An algorithm was developed in order to segment and track brachytherapy needles inserted along oblique trajectories. Three-dimensional (3D) transrectal ultrasound (TRUS) images of the rigid rod simulating the needle inserted into the tissue-mimicking agar and chicken breast phantoms were obtained to test the accuracy of the algorithm under ideal conditions. Because the robot possesses high positioning and angulation accuracies, we used the robot as a "gold standard," and compared the results of algorithm segmentation to the values measured by the robot.

A new three-dimensional ultrasound microimaging technology for preclinical studies using a transgenic prostate cancer mouse model.

Prostate cancer is the most common cancer in adult men in North America. Preclinical studies of prostate cancer employ genetically engineered mouse models, because prostate cancer does not occur naturally in rodents. Widespread application of these models has been limited because autopsy was the only reliable method to evaluate treatment efficacy in longitudinal studies.

Brachytherapy needle deflection evaluation and correction.

In prostate brachytherapy, an 18-gauge needle is used to implant radioactive seeds. This thin needle can be deflected from the preplanned trajectory in the prostate, potentially resulting in a suboptimum dose pattern and at times requiring repeated needle insertion to achieve optimal dosimetry. In this paper, we report on the evaluation of brachytherapy needle deflection and bending in test phantoms and two approaches to overcome the problem.

3D ultrasound imaging of the carotid arteries.

Although ultrasonography is an important cost-effective imaging modality, technical improvements are needed before its full potential is realized for accurate and reproducible monitoring of carotid disease and plaque burden. 2D viewing of 3D anatomy, using conventional ultrasonography limits our ability to quantify and visualize carotid disease and is partly responsible for the reported variability in diagnosis and monitoring of disease progression. Efforts of investigators have focused on overcoming these deficiencies by developing 3D ultrasound imaging techniques that are capable of acquiring B-mode, color Doppler and power Doppler images of the carotid arteries using existing conventional ultrasound systems, reconstructing the information into 3D images, and then allowing interactive viewing of the 3D images on inexpensive desktop computers.

Serial histopathology results of salvage cryoablation for prostate cancer after radiation failure.

Purpose: There has been a paucity of long-term followup reports of cryoablation for prostate cancer. In particular, little is known regarding the long-term histological results following salvage cryoablation. We report serial biopsy results of up to 43 months on 106 patients who underwent cryoablation after radical radiotherapy failed.

Sonography of peripheral nerves: technique, anatomy, and pathology.

Sonography provides a unique method for evaluating peripheral nerves because of its high spatial resolution, its ability to follow structures over long distances in a limb, and its dynamic nature that allows movement of patient and transducer. When combined with the wide availability and relatively low cost, sonography is an excellent modality for peripheral nerve assessment. The authors review the techniques used in assessment of peripheral nerves, the relevant anatomy, and common pathologic processes.

Three-dimensional ultrasound imaging and its use in quantifying organ and pathology volumes.

Although ultrasonography is an important cost-effective imaging modality, technical improvements are needed before its full potential is realized for accurate and reproducible monitoring of disease progression or regression. Two-dimensional viewing of three-dimensional anatomy, using conventional ultrasonography, limits our ability to quantify and visualize pathology and is partly responsible for the reported variability in diagnosis and monitoring of disease progression. Efforts of investigators have focused on overcoming these deficiencies by developing 3D ultrasound imaging techniques that are capable of acquiring B-mode images using existing conventional ultrasound systems, reconstructing the information into 3D images, and then allowing interactive viewing of the 3D images on inexpensive desktop computers.

Prostate boundary segmentation from 3D ultrasound images.

Segmenting, or outlining the prostate boundary is an important task in the management of patients with prostate cancer. In this paper, an algorithm is described for semiautomatic segmentation of the prostate from 3D ultrasound images. The algorithm uses model-based initialization and mesh refinement using an efficient deformable model.

Testing and optimization of a semiautomatic prostate boundary segmentation algorithm using virtual operators.

Image analysis tasks such as size measurement and landmark-based registration require the user to select control points in an image. The output of such algorithms depends on the choice of control points. Since the choice of points varies from one user to the next, the requirement for user input introduces variability into the output of the algorithm.

Training module to teach ultrasound-guided breast biopsy skills to residents improves accuracy.

Objective: To evaluate the effectiveness of a training module in teaching residents the skills necessary to perform accurate and safe ultrasound-guided breast biopsies (USGBB).

Methods: Twelve residents with no USGBB experience, but variable ultrasound (US) experience, were randomly assigned to 2 groups; 1 group participated in a training module, and the other received no training. Each resident then attempted 30 core biopsies of "lesions" implanted in breast phantoms.

Semiautomatic three-dimensional segmentation of the prostate using two-dimensional ultrasound images.

In this paper, we report on two methods for semiautomatic three-dimensional (3-D) prostate boundary segmentation using 2-D ultrasound images. For each method, a 3-D ultrasound prostate image was sliced into the series of contiguous 2-D images, either in a parallel manner, with a uniform slice spacing of 1 mm, or in a rotational manner, about an axis approximately through the center of the prostate, with a uniform angular spacing of 5 degrees. The segmentation process was initiated by manually placing four points on the boundary of a selected slice, from which an initial prostate boundary was determined.

Comparison of core needle breast biopsy techniques: freehand versus three-dimensional US guidance.

Rationale And Objectives: No single method is generally accepted for evaluating the accuracy of breast biopsy techniques before their clinical implementation. The purpose of this study was to test a new process for evaluating biopsy techniques by using it in the evaluation of a prototype three-dimensional ultrasound (US)-guided biopsy device.

Materials And Methods: The biopsy accuracy of a new three-dimensional US-guided breast biopsy device was compared to that of the accepted clinical practice of biopsy by expert radiologists with two-dimensional freehand US guidance.

Three dimensional transrectal ultrasound imaging of the prostate: initial experience with an emerging technology.

PURPOSE: A three-dimensional ultrasound system (3-D US) was evaluated for its clinical utility in transrectal prostate imaging, in comparison with the current standard 2-dimensional transrectal ultrasound (TRUS) imaging system. METHODS AND MATERIALS: The computer program developed in our laboratory was coupled with a commercially available ultrasound transducer. Geometric validation and volumetric assessment was performed with "stretched-string" wire models and solution-containing balloons respectively.