BACKGROUND AND PURPOSE:The necessity for structural MRI is greater than ever to both diagnose AD in its early stage and objectively evaluate its progression. We propose a new VBM-based software program for automatic detection of early specific atrophy in AD.

Through visual assessment by three-dimensional (3D) brain image analysis methods using stereotactic brain coordinates system, such as three-dimensional stereotactic surface projections and statistical parametric mapping, it is difficult to quantitatively assess anatomical information and the range of extent of an abnormal region. In this study, we devised a method to quantitatively assess local abnormal findings by segmenting a brain map according to anatomical structure. Through quantitative local abnormality assessment using this method, we studied the characteristics of distribution of reduced blood flow in cases with dementia of the Alzheimer type (DAT). Using twenty-five cases with DAT (mean age, 68.9 years old), all of whom were diagnosed as probable Alzheimer's disease based on NINCDS-ADRDA, we collected I-123 iodoamphetamine SPECT data. A 3D brain map using the 3D-SSP program was compared with the data of 20 cases in the control group, who age-matched the subject cases. To study local abnormalities on the 3D images, we divided the whole brain into 24 segments based on anatomical classification. We assessed the extent of an abnormal region in each segment (rate of the coordinates with a Z-value that exceeds the threshold value, in all coordinates within a segment), and severity (average Z-value of the coordinates with a Z-value that exceeds the threshold value). This method clarified orientation and expansion of reduced accumulation, through classifying stereotactic brain coordinates according to the anatomical structure. This method was considered useful for quantitatively grasping distribution abnormalities in the brain and changes in abnormality distribution.

To make it possible to share a normal database in single photon emission computed tomography (SPECT) studies, we developed a new method for converting a SPECT image in one physical condition to that in another condition for data acquisition and reconstruction. A Hoffman 3-dimensional brain phantom experiment was conducted to determine systematic differences between collimators and reconstruction processes. SPECT images for the brain phantom were obtained using fan-beam collimators with scatter and attenuation corrections and using parallel-hole collimators without any correction. Dividing these two phantom images after anatomical standardization by Statistical Parametric Mapping 99 (SPM99) created a 3-dimensional conversion map. This conversion map was applied to convert an anatomically standardized SPECT image using parallel-hole collimators without any correction to that using fan-beam collimators with scatter and attenuation corrections in eleven subjects who underwent sequential SPECT measurements using different collimators after injection of 99mTc ethyl cysteinate dimer. The SPM99 demonstrated adequate validity of this conversion in comparative analyses of these sequential SPECT images with different collimators. This may be a promising approach for further sharing of a normal database in SPECT imaging between different cameras.

Since the degree of expertise of the observers with respect to reading eZIS did not influence the performance and an eZIS can use a common normal database by converting site-specific SPECT data to the core data, the eZIS was considered to be very useful for diagnosing early AD in routine studies in many institutions.

The Japanese EC-IC bypass trial (JET study) was established to evaluate the validity of MCA-STA anastomosis in intracranial arterial occlusive disease aiming at stroke prevention. This study must use an objective method to reliably estimate hemodynamic brain ischemia. We devised a method of objectively classifying the severity of hemodynamic ischemia using quantitatively analytical and display software, stereotactic extraction estimation for stereotactic brain coordinates and three-dimensional stereotactic surface projections (3D-SSP). We analyzed data from 16 patients registered in the JET study. Our method offers quantitative information and 3-dimensional displays of the CBF at rest and after Diamox challenge, vascular reserve and the severity of the hemodynamic brain ischemia. We compared the maximal projection counts with ROI data from tomographic images in the anterior commissure-posterior commissure plane. The maximal counts data correlated closely with the ROI data of rest and with Diamox SPECT images (both p < 0.0001). The slopes of the linear regression line were 1.15 and 1.12, respectively. The results of this study indicated that our method could simply and objectively evaluate the severity of impaired brain circulation. This procedure should support the evaluation of hemodynamic ischemia in the JET study although validation is required by several institutions using more study subjects.

A SISCOM technique of ictal and interictal SPECT images provides higher predictive value of good surgical outcome and more reliability on the diagnosis of the epileptogenic focus than side-by-side comparison in medically intractable partial epilepsy.

Baseline SPECT can identify brain perfusion abnormalities among patients with MCI for progression to PMCI. This imaging modality may aid in MCI treatment stratification.

Statistical brain imaging analysis has good objectivity and reproducibility. In Japan, statistical parametric mapping (SPM) and three-dimensional stereotactic surface projections (3D-SSP) are used nationwide as statistical imaging analysis with standard brain coordinates. They often help to interpret brain single photon emission computed tomography (SPECT) images by avoiding possible pitfalls (e.g., effects of aging, atrophy) with which clinicians are unfamiliar. However, this type of analysis presents a problem: statistical processing requires many normal subject images. The easy Z-score imaging system (eZIS) is one of the statistical analysis methods that uses SPM processing in normalization and smoothing, and it has the function of image conversion leading to statistical analysis without a control database. Therefore, statistical analysis can be used in clinical practice by sharing a prepared normal database. By unifying the image quality by processing a shared database, this program has great potential for sharing patient imaging data in many hospitals. It is expected that the eZIS will help perform detailed analysis in many functional diseases in collaborative studies. This article describes the interpretation of brain SPECT images and suggests the usefulness and potential of eZIS.