Sherif G. Nour

Real-time magnetic resonance-guided stereotactic laser amygdalohippocampotomy for mesial temporal lobe epilepsy.

BACKGROUND Open surgery effectively treats mesial temporal lobe epilepsy, but carries the risk of neurocognitive deficits, which may be reduced with minimally invasive alternatives. OBJECTIVE To describe technical and clinical outcomes of stereotactic laser amygdalohippocampotomy with real-time magnetic resonance thermal imaging guidance. METHODS With patients under general anesthesia and using standard stereotactic methods, 13 adult patients with intractable mesial temporal lobe epilepsy (with and without mesial temporal sclerosis [MTS]) prospectively underwent insertion of a saline-cooled fiberoptic laser applicator in amygdalohippocampal structures from an occipital trajectory. Computer-controlled laser ablation was performed during continuous magnetic resonance thermal imaging followed by confirmatory contrast-enhanced anatomic imaging and volumetric reconstruction. Clinical outcomes were determined from seizure diaries. RESULTS A mean 60% volume of the amygdalohippocampal complex was ablated in 13 patients (9 with MTS) undergoing 15 procedures. Median hospitalization was 1 day. With follow-up ranging from 5 to 26 months (median, 14 months), 77% (10/13) of patients achieved meaningful seizure reduction, of whom 54% (7/13) were free of disabling seizures. Of patients with preoperative MTS, 67% (6/9) achieved seizure freedom. All recurrences were observed before 6 months. Variances in ablation volume and length did not account for individual clinical outcomes. Although no complications of laser therapy itself were observed, 1 significant complication, a visual field defect, resulted from deviated insertion of a stereotactic aligning rod, which was corrected before ablation. CONCLUSION Real-time magnetic resonance-guided stereotactic laser amygdalohippocampotomy is a technically novel, safe, and effective alternative to open surgery. Further evaluation with larger cohorts over time is warranted.

The impact of multiparametric pelvic magnetic resonance imaging on risk stratification in patients with localized prostate cancer.

OBJECTIVE To determine the impact of multiparametric magnetic resonance imaging (MP-MRI) of the prostate on established risk stratification criteria in patients with clinically localized adenocarcinoma of the prostate (ACP). METHODS The cohort included 71 patients who underwent MP-MRI of the prostate at a tertiary care referral center as part of their initial workup for ACP. Tumor characteristics comprising traditional risk stratification criteria (prostate-specific antigen, clinical T stage, and biopsy Gleason score) were recorded, and the initial National Comprehensive Cancer Network risk group was calculated. The National Comprehensive Cancer Network risk group was then recalculated incorporating MRI findings. The impact of MRI findings on changes in risk group classification was evaluated using the Stuart-Maxwell test. For patients undergoing radical prostatectomy, MRI findings were correlated with pathologic findings. RESULTS The cohort included 11 (15.5%), 39 (54.9%), and 21 patients (29.6%) with low-, intermediate-, and high-risk disease, respectively. MRI findings led to risk group upstaging in 12 cases (16.9%). The highest yield was demonstrated in patients with intermediate-risk disease, in whom MRI led to upstaging in 25.6% of patients. There was a significant difference between pre-MRI and post-MRI risk group classifications (P<.01) for the entire cohort. Compared with radical prostatectomy specimens, the specificity of MRI for T3 disease was 92.9%. CONCLUSION In our cohort of patients undergoing MP-MRI for previously untreated, clinically localized ACP, MRI findings led to changes in risk stratification in a substantial proportion of patients. Our findings support the use of MP-MRI in the workup of patients with localized ACP.

The potential role of magnetic resonance spectroscopy in image-guided radiotherapy.

Magnetic resonance spectroscopy (MRS) is a non-invasive technique to detect metabolites within the normal and tumoral tissues. The ability of MRS to diagnose areas of high metabolic activity linked to tumor cell proliferation is particularly useful for radiotherapy treatment planning because of better gross tumor volume (GTV) delineation. The GTV may be targeted with higher radiation dose, potentially improving local control without excessive irradiation to the normal adjacent tissues. Prostate cancer and glioblastoma multiforme (GBM) are two tumor models that are associated with a heterogeneous tumor distribution. Preliminary studies suggest that the integration of MRS into radiotherapy planning for these tumors is feasible and safe. Image-guided radiotherapy (IGRT) by virtue of daily tumor imaging and steep dose gradient may allow for tumor dose escalation with the simultaneous integrated boost technique (SIB) and potentially decrease the complications rates in patients with GBM and prostate cancers.

Magnetic Resonance Image-Guided Focal Prostate Ablation.

Prostate cancer is the most common cancer (other than skin cancer) in American men, with one in seven men being diagnosed with this disease during his lifetime. The estimated number of new prostate cancer cases in 2016 is 180,890. For the first time, imaging has become the center of the search for contained, intraglandular, small-volume, and unifocal disease, and an increasing number of academic institutions as well as private practices are implementing programs for prostate multiplanar magnetic resonance imaging (MRI) as parts of their routine offerings. This article reviews the role of MRI-guided focal prostate ablation, as well as opportunities for further growth in this minimally invasive therapy of prostate cancer.

The Urinary Tract: Renal Collecting Systems, Ureters, and Urinary Bladder

Various pathologies can involve the urinary tract. In this chapter, we start by illustrating the gross anatomy of the urinary tract. Then, through practical algorithmic approach, we will discuss various patterns that can help in the differential diagnosis and guide radiologists to make a practical differential diagnosis and often reach a specific diagnosis.

Percutaneous selective laser amygdalo-hippocampectomy (SLAH) for treatment of mesial temporal lobe epilepsy within an interventional MRI suite

Abstract Percutaneous selective laser amygdalo-hippocampectomy (SLAH) procedure is a new minimally invasive alternative to surgical amygdalo-hippocampectomy that involves targeted, controlled laser energy deposition under real-time magnetic resonance imaging (MRI) monitoring within a dedicated “interventional MRI” suite. Technical feasibility, safety and initial efficacy results from our program are encouraging and indicate a potential for paradigm shift in future treatment of patients with exclusively or predominantly focal unilateral seizure onsets within the mesial temporal lobe. Several institutions are currently employing this technology and more long-term follow-up results on larger cohorts of patients are expected in the near future. This article reviews the principles of MRI-guided SLAH, procedure set-up and equipment, the detailed phases of intra-procedural MRI guidance and treatment monitoring, and the MRI appearance of the resultant thermal ablation zones. We conclude with a discussion of our institutional experience at Emory University with MRI-guided SLAH as one of the leading sites offering this state-of-the-art technology.

MRI-Guided RF Ablation in the Kidney

Percutaneous thermal ablation has become a viable option for locoregional control of cancer. In contrast to its role in most applications, thermal ablation in the kidney typically targets localized primary tumors with the aim of complete treatment. Radiofrequency ablation and cryoablation are the most commonly used thermal energy techniques for this purpose. The use of MRI to guide and monitor these ablation procedures is associated with a considerably more refined technique primarily owing to the ability of MRI to monitor the thermal effects of tissue heating as they occur. As such, MRI permits a tailored approach to treatment based on the actual visualization of individual tumor response. This represents a fundamental difference from performing these procedures under CT or ultrasound guidance when the implemented treatment paradigm follows a predetermined recipe based on experience collected during the treatment of similar tumors. In this chapter, a discussion of the rationale of image guidance during ablation is provided with a special emphasis on the added value of the use of MRI during both the guidance and the monitoring phases of treatment. The interventional MRI suite setup and equipment are explained, followed by a detailed practical approach to the ablation procedure under MRI. The cellular bases of MRI findings on follow-up imaging are then elucidated, and the chapter is concluded by a discussion of various safety measures to be followed during MRI-guided radiofrequency ablation procedures.

MRI-Guided Laser Ablation of Liver Tumors

Percutaneous thermal ablation has become a viable option for locoregional control of localized hepatic malignancy. Commonly used ablative technologies include radiofrequency, microwave, and cryoablation. The use of MRI to guide and monitor these ablation procedures is associated with a considerably more refined technique primarily due to the ability of MRI to monitor the thermal effects of tissue heating as they occur. As such, MRI facilitates a tailored approach to treatment based on the actual visualization of individual tumor response. This approach represents a fundamental conceptual departure from the current standard CT- and ultrasound-guided ablations where amount and duration of deployed energy follow a predetermined “recipe” based on vendor’s recommendation and user’s experience. In this chapter, we introduce the readers to the basics of laser/tissue interactions during ablation. We then elaborate on the multifaceted role of MRI during liver ablation and how it contributes to creating a new refined approach to these procedures. We build on this background to transition to the rationale of choosing laser energy for ablation and how it best suits the MRI environment. We then describe the interventional MRI suite setup for liver laser ablation and conclude with a detailed step-by-step description of the various technical phases of guiding and monitoring a liver laser ablation procedure under MRI.

MR Imaging–Guided Focal Treatment of Prostate Cancer: An Update

Focal treatment of prostate cancer has evolved from a concept to a practice in the recent few years and is projected to fill an existing need, bridging the gap between conservative and radical traditional treatment options. With its low morbidity and rapid recovery time compared with whole-gland treatment alternatives, focal therapy is poised to gain more acceptance among patients and health care providers. As our experience with focal treatment matures and evidence continues to accrue, the landscape of this practice might look quite different in the future.

Reproducibility in contouring the neurovascular bundle for prostate cancer radiation therapy

PURPOSE Efforts to define the neurovascular bundle (NVB) for prostate radiation have varied. In this series, we sought to determine the reproducibility and reliability of contouring the classical posterolateral NVB on dedicated pelvic magnetic resonance imaging (MRI) scans. METHODS AND MATERIALS A total of 120 NVB structures were defined on 10 3-Tesla pelvic MRI scans in patients with prostate cancer but without extraprostatic extension. One pelvic radiologist served as the expert in contouring the right and left NVB for each case. Five radiation oncologists, with varying levels of experience, contoured the right and left NVBs on these same cases. The intraclass correlation coefficient across each rater and the expert, Pearson correlation coefficient between each rater and the expert, and the Dice similarity coefficient (DSC) between each rater and the expert were calculated to evaluate contour agreement and overlap. RESULTS The overall intraclass correlation coefficient was 0.89 (95% confidence interval [CI], 0.81-0.95). The Pearson correlation coefficient was 0.95 (95% CI, 0.86-0.98) for rater 1, 0.98 (95% CI, 0.95-0.99) for rater 2, 0.94 (95% CI, 0.86-0.98) for rater 3, 0.98 (95% CI, 0.95-0.99) for rater 4, and 0.84 (95% CI, 0.63-0.93) for rater 5. The mean DSC was 0.72 (standard deviation [SD], 0.07) for rater 1, 0.72 (SD, 0.06) for rater 2, 0.73 (SD, 0.09) for rater 3, 0.74 (SD, 0.09) for rater 4, and 0.68 (SD, 0.13) for rater 5. Overall, across all raters, the average DSC was 0.72 (SD, 0.09). CONCLUSIONS The classic posterolateral NVB can be accurately and reliably contoured on 3-Tesla pelvic MRI scans by radiation oncologists.