Biomaterial Database

Sequential magnetic resonance imaging following stereotactic radiofrequency ventralis lateralis thalamotomy. 1991

F H Tomlinson, and C R Jack, and P J Kelly

Department of Neurologic Surgery, Mayo Clinic, Rochester, Minnesota.

Serial postoperative magnetic resonance (MR) studies were obtained in 21 patients who underwent somatotopically placed stereotactic radiofrequency (rf) ventralis lateralis thalamotomy for the control of movement disorders. The MR studies were reviewed to determine the MR characteristics of early-phase (less than or equal to 7 days) and late-phase (8 days to 5 months) lesions. Surgery was performed for the control of parkinsonian tremor (14 cases), intention tremor (six cases), and essential tremor (one case). Single rf lesions were made with an electrode (1.6 mm in diameter, 3 mm in tip length) heated to 78 degrees C for 60 seconds. On MR images of the lesions, three distinct concentric zones were identified, described as follows (from the center outward). Zone 1 gives increased signal on long-relaxation time (TR) (T2-weighted) MR images in early- and late-phase lesions and decreased signal on short-TR (T1-weighted) MR images in early-phase lesions only. Zone 2 gives decreased signal on long-TR (T2-weighted) images in early- and late-phase lesions; it gives isointense signal on short-TR (T1-weighted) images in early-phase lesions only. Zone 3 gives increased signal on long-TR (T2-weighted) images in early-phase lesions only and decreased signal on short-TR (T1-weighted) MR images in early-phase lesions only. It is considered that in early-phase lesions, Zone 2, with a mean diameter of 7.3 mm on axial long-TR (T2-weighted) imaging, represents an area of hemorrhagic coagulation necrosis. In late-phase lesions, Zone 2, with a mean diameter of 5.0 mm on axial long-TR (T2-weighted) imaging, represents hemosiderin deposition. Zone 3 likely represents edema, and this zone disappears between the early and late periods. From regression analysis, lesion size began to stabilize at approximately 7 months with a mature lesion diameter of 3.3 mm. Long-term follow-up monitoring (median 16 months) showed good tremor control. Based on clinical and radiological findings, the authors conclude that forms of hemoglobin are suitable markers to assess the size of rf lesions. Serial MR imaging provides a noninvasive means of studying the evolution of rf thalamotomy lesions.

UI	MeSH Term	Description	Entries
D008279	Magnetic Resonance Imaging	Non-invasive method of demonstrating internal anatomy based on the principle that atomic nuclei in a strong magnetic field absorb pulses of radiofrequency energy and emit them as radiowaves which can be reconstructed into computerized images. The concept includes proton spin tomographic techniques.	Chemical Shift Imaging,MR Tomography,MRI Scans,MRI, Functional,Magnetic Resonance Image,Magnetic Resonance Imaging, Functional,Magnetization Transfer Contrast Imaging,NMR Imaging,NMR Tomography,Tomography, NMR,Tomography, Proton Spin,fMRI,Functional Magnetic Resonance Imaging,Imaging, Chemical Shift,Proton Spin Tomography,Spin Echo Imaging,Steady-State Free Precession MRI,Tomography, MR,Zeugmatography,Chemical Shift Imagings,Echo Imaging, Spin,Echo Imagings, Spin,Functional MRI,Functional MRIs,Image, Magnetic Resonance,Imaging, Magnetic Resonance,Imaging, NMR,Imaging, Spin Echo,Imagings, Chemical Shift,Imagings, Spin Echo,MRI Scan,MRIs, Functional,Magnetic Resonance Images,Resonance Image, Magnetic,Scan, MRI,Scans, MRI,Shift Imaging, Chemical,Shift Imagings, Chemical,Spin Echo Imagings,Steady State Free Precession MRI
D009336	Necrosis	The death of cells in an organ or tissue due to disease, injury or failure of the blood supply.
D011183	Postoperative Complications	Pathologic processes that affect patients after a surgical procedure. They may or may not be related to the disease for which the surgery was done, and they may or may not be direct results of the surgery.	Complication, Postoperative,Complications, Postoperative,Postoperative Complication
D012044	Regression Analysis	Procedures for finding the mathematical function which best describes the relationship between a dependent variable and one or more independent variables. In linear regression (see LINEAR MODELS) the relationship is constrained to be a straight line and LEAST-SQUARES ANALYSIS is used to determine the best fit. In logistic regression (see LOGISTIC MODELS) the dependent variable is qualitative rather than continuously variable and LIKELIHOOD FUNCTIONS are used to find the best relationship. In multiple regression, the dependent variable is considered to depend on more than a single independent variable.	Regression Diagnostics,Statistical Regression,Analysis, Regression,Analyses, Regression,Diagnostics, Regression,Regression Analyses,Regression, Statistical,Regressions, Statistical,Statistical Regressions
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D013788	Thalamus	Paired bodies containing mostly GRAY MATTER and forming part of the lateral wall of the THIRD VENTRICLE of the brain.	Thalamencephalon,Thalamencephalons
D014202	Tremor	Cyclical movement of a body part that can represent either a physiologic process or a manifestation of disease. Intention or action tremor, a common manifestation of CEREBELLAR DISEASES, is aggravated by movement. In contrast, resting tremor is maximal when there is no attempt at voluntary movement, and occurs as a relatively frequent manifestation of PARKINSON DISEASE.	Action Tremor,Intention Tremor,Resting Tremor,Coarse Tremor,Continuous Tremor,Darkness Tremor,Fine Tremor,Intermittent Tremor,Involuntary Quiver,Massive Tremor,Passive Tremor,Persistent Tremor,Pill Rolling Tremor,Rest Tremor,Saturnine Tremor,Senile Tremor,Static Tremor,Tremor, Limb,Tremor, Muscle,Tremor, Neonatal,Tremor, Nerve,Tremor, Perioral,Tremor, Semirhythmic,Action Tremors,Coarse Tremors,Continuous Tremors,Darkness Tremors,Fine Tremors,Intention Tremors,Intermittent Tremors,Involuntary Quivers,Limb Tremor,Limb Tremors,Massive Tremors,Muscle Tremor,Muscle Tremors,Neonatal Tremor,Neonatal Tremors,Nerve Tremor,Nerve Tremors,Passive Tremors,Perioral Tremor,Perioral Tremors,Persistent Tremors,Pill Rolling Tremors,Quiver, Involuntary,Rest Tremors,Resting Tremors,Saturnine Tremors,Semirhythmic Tremor,Semirhythmic Tremors,Senile Tremors,Static Tremors,Tremor, Action,Tremor, Coarse,Tremor, Continuous,Tremor, Darkness,Tremor, Fine,Tremor, Intention,Tremor, Intermittent,Tremor, Massive,Tremor, Passive,Tremor, Persistent,Tremor, Pill Rolling,Tremor, Rest,Tremor, Resting,Tremor, Saturnine,Tremor, Senile,Tremor, Static,Tremors