Autoalign

AutoAlignTM Atlas-Based Image Registration software is intended to provide an output registration matrix that may be utilized to align an MRI brain scan to a known and consistent anatomic orientation, a process known as image registration. AutoAlignTM Atlas-Based Image Registration software is intended to be marketed as a software device that can provide improvements to the manual processes of image registration. The dominant use of AutoAlignTM Atlas-Based Image Registration software is its integration into proprietary MR image software packages by MRI scanner manufacturers to allow users to generate consistent patient image registrations for image acquisition, a process otherwise known as Autoslice Prescriptioning.

AutoAlignTM Atlas-Based Image Registration labeling for the device contains instructions for the safe and effective use of this software as demonstrated by testing on 259 acquired image volumes (as detailed below). Labeling may vary in accordance to the proprietary MRI manufacturers systems, but includes the following language:

The accuracy of the auto alignment is affected by the subject‘s deviation from the embedded reference neuroanatomic Atlas. In general, the effectiveness of standardized image registration as measured by the AutoAlignTM Atlas-Based Image Registration software decreases when the subject’s brain includes pathologic features not present in the normal brain, lacks features normally present, or is structurally different than that defined in the pre-existing neuroanatomic Atlas of the normal brain. The accuracy of the AutoAlignTM Atlas-Based Image Registration alignment program can also be degraded by patient motion or by artifacts which are introduced into the patient scanning process. If there is a clinical requirement to characterize a mass lesion or other abnormal pathological feature which differs significantly from the normal brain, the user should not rely upon the AutoAlign feature for image registration and should manually perform image registration. To assure adequate registration is achieved, the software calculates a Measurement Index (MI) which reflects the adequacy of alignment. If the Measurement Index exceeds specified anatomic limits, user intervention is required.

Factors which degrade the technical quality of MR images or pathologic processes which significantly affect neuroanatomic structure may decrease the alignment accuracy of the Autoalign software. Such factors include:

a. Patient’s motion during scan.

c. Artifacts affecting overall image quality.

d. Brains showing gross amount of structural abnormality.

e. Resections must not be larger than 30 cc.

f. Tumors must not be larger than 15 cc.

AutoAlign demonstrates the following registration capabilities for MRI Neuro exams subject to the limitations set forth above and in product operating labeling documents:

The inter-subject variability of the position of the anterior commissure (AC) is less than 15 mm.

The inter-subject variability of the position of the posterior commissure (PC) is less than 13 mm.

The inter-subject variability of the positioning of the inter-hemispheric plane (as measured on sagittal views) is less than 6 mm.

The inter-subject variability of the angle formed by the inter-hemispheric plane and the anterior-posterior line (as measured on axial views) is less than 5.

The inter-subject variability of the angle formed by the inter-hemispheric plane and the superior-inferior line (as measured on coronal views) is less than 7 degrees.