Automated brain MRI and CT prescriptions in Talairach space
Brain Magnetic Resonance Imaging (MRI), Computerized Tomotography (CT), or other diagnostic modalities may employ a three-step procedure during initial (“scout”) cranial pre-scans that corrects for patient positioning (i.e., roll, yaw and pitch) to reduce inter- and intra-patient variation, thereby enhancing the diagnostic and comparative value of subsequent detail scans even across different diagnostic platforms. In MRI, for instance, locating the saggital sinus (SS) and optimizing a line to bisect the brain through this SS may be automated to correct for roll and yaw. By then identifying the contour of the corpus callosum in a lateral saggital scout scan, the Talairach anterior commissure (AC)—posterior commissure (PC) reference line may be found for correcting pitch. Prescription of detailed scans are improved, especially when the three-step correction is repeated periodically identifying the need to repeat a detailed scan or to adjust the coordinates of a subsequent scan.
1. A method of identifying a head position of a patient undergoing diagnostic imaging, comprising:
obtaining a diagnostic image of a patient's head with a diagnostic imaging machine;
performing an automated image processing operation to determine coordinates of a Talairach anterior commissure (AC)—posterior commissure (PC) reference line within the diagnostic image by identifying a line passing through a hard palate on the diagnostic image and utilizing the identified line to approximate the Talairach AC-PC reference line as about 12 degrees more extended than the hard palate in a lateral midline image; and
defining a coordinate system of the diagnostic image with reference to the Talairach AC-PC reference line.
2. The method of claim 1 , further comprising:
prescribing a subsequent scan based on the identified Talairach AC-PC reference line and coordinate system; and
repeating the automated image processing operation to determine current coordinates of the Talairach AC-PC reference for accommodating changes in patient head position since the previous position determination.
3. The method of claim 1 , wherein obtaining a diagnostic image comprises obtaining a roll and yaw corrected thin section midsagittal magnetic resonance imaging (MRI) image of the patient's head.
4. The method of claim 3 , wherein obtaining a midsagittal MRI image of a patient's head further comprises:
obtaining at least two scout views;
identifying midline features to permit correction of roll and yaw; and
obtaining a midsagittal MRJ image based on identified midline features.
5. The method of claim 4 , wherein obtaining a midsagittal MRI image of a patient's head when identifying midline features to permit correction of roll and yaw further comprises:
performing at least one rapid scan operatively configured to accentuate venous blood flow in the superior sagittal sinus (SSS) in a plane selected from a group consisting of coronal scan, axial scan and oblique scan of the patient's head;
identifying the SSS in cross-section in the at least one rapid scan;
identifying a line that bisects the brain with the line passing through the SSS cross-section; and
defining an attitude correction selected from a group consisting of roll correction and yaw correction corresponding to the selected plane for subsequent scans based on the identified line that bisects the brain.
6. The method of claim 1 , wherein obtaining a diagnostic image comprises obtaining a lateral computerized tomography (CT) scout image.
7. The method of claim 6 , wherein obtaining a lateral CT scout image of a patient's head further comprises physically adjusting patient's head position relative to a scanner that obtains the lateral CT scout image for minimizing roll and yaw visually.
8. A program product embodied in a tangible, recordable media, comprising:
(a) a program configured to receive a thin section diagnostic image of a patient's brain from a CT diagnostic imaging machine and to determine coordinates of a Talairach anterior commissure (AC)— posterior commissure (PC) reference line within the thin section diagnostic image and to define a coordinate system of the diagnostic image with reference to the Talairach AC-PC reference line; and
(b) a tangible signal bearing media bearing the program; wherein the diagnostic image is a lateral computerized tomography (CT) scout image, wherein the program is further configured to receive a midline sagittal MR scan from an MR diagnostic imaging machine, and wherein the program is further configured to:
(a) identify a line passing through the hard palate on the MR scan;
(b) calculate an angle between the patient's hard palate and the Talairach AC-PC reference line in the MR scan;
(c) identify a line passing through the patient's hard palate on the diagnostic image; and,
(d) utilize the calculated angle to adjust a CT pitch prescription.
9. The program product of claim 8 , wherein determining coordinates of the Talairach AC-PC reference line comprises iteratively searching for and identifying landmarks on the diagnostic image, these landmarks selected from the group consisting of superior sagittal sinus (SSS), corpus callosum, a rostrum of the corpus callosum, an inferior edge splenium of the corpus callosum, mammilary bodies, fornices, and a superior margin of a brainstem.
10. The program product of claim 8 , wherein the diagnostic image is a roll and yaw corrected sagittal image section, and wherein wherein determining coordinates of the Talairach AC-PC reference line comprises:
a) referencing a template dataset with a known Talairach AC-PC reference line; and
b) iteratively minimizing a difference between the sagittal image section and the template dataset.
11. The program product of claim 10 , wherein referencing the template dataset further comprises obtaining a previous scan of the same patient with a known Talairach AC-PC reference line.
12. The program product of claim 10 , wherein referencing the template dataset further comprises obtaining an institutional standard dataset of an averaged template with a known Talairach AC-PC reference line.