RATIONALE AND OBJECTIVES: The accuracy of diagnostic test and imaging segmentation is important in clinical practice because it has a direct impact on therapeutic planning. Statistical validations of classification accuracy was conducted based on parametric receiver operating characteristic analysis, illustrated on three radiologic examples, MATERIALS AND METHODS: Two parametric models were developed for diagnostic or imaging data. Example 1: A semi-automated fractional segmentation algorithm was applied to magnetic resonance imaging of nine cases of brain tumors. The tumor and background pixel data were assumed to have bi-beta distributions. Fractional segmentation was validated against an estimated composite pixel-wise gold standard based on multi-reader manual segmentations. Example 2: The predictive value of 100 cases of spiral computed tomography of ureteral stone sizes, distributed as bi-normal after a non-linear transformation, under two treatment options received. Example 3: One hundred eighty cases had prostate-specific antigen levels measured in a prospective clinical trial. Radical prostatectomy was performed in all to provide a binary gold standard of local and advanced cancer stages. Prostate-specific antigen level was transformed and modeled by bi-normal distributions. In all examples, areas under the receiver operating characteristic curves were computed. RESULTS. The areas under the receiver operating characteristic curves were: Example 1: Fractional segmentation of magnetic resonance imaging of brain tumors: meningiomas (0.924-0.984); astrocytomas (0.786-0.986); and other low-grade gliomas (0.896-0.983). Example 3: Ureteral stone size for treatment planning (0.813). Example 2: Prostate-specific antigen for staging prostate cancer (0.768). CONCLUSION: All clinical examples yielded fair to excellent accuracy. The validation metric area under the receiver operating characteristic curves may be generalized to evaluating the performances of several continuous classifiers related to imaging.

BACKGROUND: The Heschl gyrus and planum temporale have crucial roles in auditory perception and language processing. Our previous investigation using magnetic resonance imaging (MRI) indicated smaller gray matter volumes bilaterally in the Heschl gyrus and in left planum temporale in patients with first-episode schizophrenia but not in patients with first-episode affective psychosis. We sought to determine whether there are progressive decreases in anatomically defined MRI gray matter volumes of the Heschl gyrus and planum temporale in patients with first-episode schizophrenia and also in patients with first-episode affective psychosis. METHODS: At a private psychiatric hospital, we conducted a prospective high spatial resolution MRI study that included initial scans of 28 patients at their first hospitalization (13 with schizophrenia and 15 with affective psychosis, 13 of whom had a manic psychosis) and 22 healthy control subjects. Follow-up scans occurred, on average, 1.5 years after the initial scan. RESULTS: Patients with first-episode schizophrenia showed significant decreases in gray matter volume over time in the left Heschl gyrus (6.9%) and left planum temporale (7.2%) compared with patients with first-episode affective psychosis or control subjects. CONCLUSIONS: These findings demonstrate a left-biased progressive volume reduction in the Heschl gyrus and planum temporale gray matter in patients with first-episode schizophrenia in contrast to patients with first-episode affective psychosis and control subjects. Schizophrenia but not affective psychosis seems to be characterized by a postonset progression of neocortical gray matter volume loss in the left superior temporal gyrus and thus may not be developmentally fixed.

We propose a shape-based approach to curve evolution for the segmentation of medical images containing known object types. In particular, motivated by the work of Leventon, Grimson, and Faugeras, we derive a parametric model for an implicit representation of the segmenting curve by applying principal component analysis to a collection of signed distance representations of the training data. The parameters of this representation are then manipulated to minimize an objective function for segmentation. The resulting algorithm is able to handle multidimensional data, can deal with topological changes of the curve, is robust to noise and initial contour placements, and is computationally efficient. At the same time, it avoids the need for point correspondences during the training phase of the algorithm. We demonstrate this technique by applying it to two medical applications; two-dimensional segmentation of cardiac magnetic resonance imaging (MRI) and three-dimensional segmentation of prostate MRI.

CONTEXT: Whether psychoses associated with schizophrenia and affective disorder represent manifestations of different disorders or the same disorder is an important but unresolved question in psychiatry. Results of previous volumetric magnetic resonance imaging investigations indicate that gray matter volume reductions in neocortical regions may be specific to schizophrenia. OBJECTIVE: To simultaneously evaluate multiple olfactocentric paralimbic regions, which play crucial roles in human emotion and motivation, in first-episode patients with schizophrenia and affective psychosis. DESIGN: A cross-sectional study using high-spatial resolution magnetic resonance imaging in patients with schizophrenia and affective psychosis at their first hospitalization. SETTING: Inpatient units at a private psychiatric hospital. PARTICIPANTS: Fifty-three first-episode patients, 27 with schizophrenia and 26 with affective (mainly manic) psychosis, and 29 control subjects. MAIN OUTCOME MEASURES: Using high-spatial resolution magnetic resonance imaging, the gray matter volumes of 2 olfactocentric paralimbic regions of interest, the insular cortex and the temporal pole, were evaluated. RESULTS: A bilateral volume reduction in insular cortex gray matter was specific to first-episode patients with schizophrenia. In contrast, both first-episode psychosis groups showed a volume reduction in left temporal pole gray matter and an absence of normal left-greater-than-right asymmetry. Region of interest correlations showed that only patients with schizophrenia lacked a positive correlation between left temporal pole and left anterior amygdala-hippocampal complex gray matter volumes, whereas both psychosis groups were similar in lacking normal positive correlations between left temporal pole and left anterior superior temporal gyrus gray matter volumes. CONCLUSIONS: These partially different and partially similar patterns of structural abnormalities in olfactocentric paralimbic regions and their associated abnormalities in other temporolimbic regions may be important factors in the differential and common manifestations of the 2 psychoses.

Current clinical practice in the premature infant with posthaemorrhagic ventricular dilatation (PHVD) includes drainage of cerebrospinal fluid (CSF). This case study used advanced volumetric three dimensional magnetic resonance imaging to document the impact of CSF removal on the volume of regional brain tissues in a premature infant with PHVD. The removal of a large volume of CSF was associated with an identical reduction in CSF volume, but more dramatically with a significant increase in the regional volumes of cortical grey matter and myelinated white matter. The alterations in cerebral cortical grey matter and myelinated white matter volumes may provide insight into the established association of PHVD with deficits in cognitive and motor functions.