Simulated accuracy assessment of small footprint body-mounted probe alignment device for MRI-guided cryotherapy of abdominal lesions.

PURPOSE: Magnetic resonance imaging (MRI)-guided percutaneous cryotherapy of abdominal lesions, an established procedure, uses MRI to guide and monitor the cryoablation of lesions. Methods to precisely guide cryotherapy probes with a minimum amount of trial-and-error are yet to be established. To aid physicians in attaining precise probe alignment without trial-and-error, a body-mounted motorized cryotherapy-probe alignment device (BMCPAD) with motion compensation was clinically tested in this study. The study also compared the contribution of body motion and organ motion compensation to the guidance accuracy of a body-mounted probe alignment device. METHODS: The accuracy of guidance using the BMCPAD was prospectively measured during MRI-guided percutaneous cryotherapies before insertion of the probes. Clinical parameters including patient age, types of anesthesia, depths of the target, and organ sites of target were collected. By using MR images of the target organs and fiducial markers embedded in the BMCPAD, we retrospectively simulated the guidance accuracy with body motion compensation, organ motion compensation, and no compensation. The collected data were analyzed to test the impact of motion compensation on the guidance accuracy. RESULTS: Thirty-seven physical guidance of probes were prospectively recorded for sixteen completed cases. The accuracy of physical guidance using the BMCPAD was 13.4 ± 11.1 mm. The simulated accuracy of guidance with body motion compensation, organ motion compensation, and no compensation was 2.4 ± 2.9 mm, 2.2 ± 1.6 mm, and 3.5 ± 2.9 mm, respectively. Data analysis revealed that the body motion compensation and organ motion compensation individually impacted the improvement in the accuracy of simulated guidance. Moreover, the difference in the accuracy of guidance either by body motion compensation or organ motion compensation was not statistically significant. The major clinical parameters impacting the accuracy of guidance were the body and organ motions. Patient age, types of anesthesia, depths of the target, and organ sites of target did not influence the accuracy of guidance using BMCPAD. The magnitude of body surface movement and organ movement exhibited mutual statistical correlation. CONCLUSIONS: The BMCPAD demonstrated guidance accuracy comparable to that of previously reported devices for CT-guided procedures. The analysis using simulated motion compensation revealed that body motion compensation and organ motion compensation individually impact the improvement in the accuracy of device-guided cryotherapy probe alignment. Considering the correlation between body and organ movements, we also determined that body motion compensation using the ring fiducial markers in the BMCPAD can be solely used to address both body and organ motions in MRI-guided cryotherapy.

The Inpatient Assessment and Management of Motor Functional Neurological Disorders: An Interdisciplinary Perspective.

BACKGROUND: Motor functional neurologic disorders (FND)-previously termed "hysteria" and later "conversion disorder"-are exceedingly common and frequently encountered in the acute hospital setting. Despite their high prevalence, patients with motor FND can be challenging to diagnose accurately and manage effectively. To date, there is limited guidance on the inpatient approach to the neuropsychiatric evaluation of patients with functional (psychogenic) neurologic symptoms. OBJECTIVE: The authors outline an inpatient multidisciplinary approach, involving neurology, psychiatry, and physical therapy, for the assessment and acute inpatient management of motor FND. METHODS: A vignette of a patient with motor FND is presented followed by a discussion of general assessment principles. Thereafter, a detailed description of the neurologic and psychiatric assessments is outlined. Delivery of a "rule-in" diagnosis is emphasized and specific guidance for what can be accomplished postdiagnosis in the hospital is suggested. DISCUSSION: We encourage an interdisciplinary approach beginning at the early stages of the diagnostic assessment once an individual is suspected of having motor FND. CONCLUSIONS: Practical suggestions for the inpatient assessment of motor FND are presented. It is also important to individualize the diagnostic assessment. Future research should be conducted to test best practices for motor FND management in the acute inpatient hospital setting.