Biomedical subjects

J L Boes

Publications and source records attributed to J L Boes.

15 recordsLinked to original sources

PubMed1999

Motion correction in fMRI via registration of individual slices into an anatomical volume.

An automated retrospective image registration based on mutual information is adapted to a multislice functional magnetic resonance imaging (fMRI) acquisition protocol to provide accurate motion correction. Motion correction is performed by mapping each slice to an anatomic volume data set acquired in the same fMRI session to accommodate inter-slice head motion. Accuracy of the registration parameters was assessed by registration of simulated MR data of the known truth. The widely used rigid body volume registration approach based on stacked slices from the time series data may hinder statistical accuracy by introducing inaccurate assumptions of no motion between slices for multislice fMRI data. Improved sensitivity and specificity of the fMRI signal from mapping-each-slice-to-volume method is demonstrated in comparison with a stacked-slice correction method by examining functional data from two normal volunteers. The data presented in a standard anatomical coordinate system suggest the reliability of the mapping-each-slice-to-volume method to detect the activation signals consistent between the two subjects.

Algorithms↗

PubMed1999

Semiautomatic registration of volumetric ultrasound scans.

We demonstrate the ability to register easily and accurately volumetric ultrasound scans without significant data preprocessing or user intervention. Two volumetric ultrasound breast scan data sets were acquired from two different patients with breast cancer. Volumetric scan data were acquired by manually sweeping a linear array transducer mounted on a linear slider with a position encoder. The volumetric data set pairs consisted of color flow and/or power mode Doppler data sets acquired serially on the same patients. A previously described semiautomatic registration method based on maximizing mutual information was used to determine the transform between data sets. The results suggest that, even for the deformable breast, three-dimensional full affine transforms can be sufficient to obtain clinically useful registrations; warping may be necessary for increased registration accuracy. In conclusion, mutual information-based automatic registration as implemented on modern workstations is capable of yielding clinically useful registrations in times <35 min.

Breast Neoplasms↗

PubMed1997

Utility of the Inventory of Suicide Orientation-30 (ISO-30) for adolescent psychiatric inpatients: linking clinical decision making with outcome evaluation.

This report describes a study that integrates program evaluation with clinical practice. The subjects were 139 adolescent psychiatric inpatients who were tested with the Inventory of Suicide Orientation-30 (ISO-30) at admission and retested six days after admission. Aggregate analyses showed statistically significant changes in the direction of decreased suicidality on all ISO-30 indices. Further analyses compared the data with normative data from the ISO-30 manual, and also evaluated the relationships between ISO-30 scores and length of stay. Implications of the results and also methods of integrating outcome with clinical practice are discussed.

Adolescent↗

PubMed1997

The relationship of length of stay to MCMI-II and MCMI-III change scores.

Differences between short versus longer lengths of stay on inpatient change scores were evaluated. Test-retest scores of 98 adult psychiatric inpatients tested with the MCMI-II in 1989 were compared with test-retest scores of 97 adult inpatients tested with the MCMI-III in 1995. The two samples of patients were comparable on demographic and diagnostic variables. Findings suggest a smaller degree of change associated with shorter lengths of stay, as measured by effect sizes and the proportions of patients moving from the clinically significant to the clinically nonsignificant range on scales for anxiety and depression.

Adult↗

PubMed1997

Comparison of psychiatric day hospital patient and inpatient scores on the MCMI-III.

This study contrasts self-reported symptomatology on the MCMI-III of a sample of 97 psychiatric patients admitted directly to inpatient care with a sample of 75 patients admitted directly to day hospital treatment. The predominant Axis I diagnosis of patients in both samples was an affective disorder. Effect sizes of the degree of change from admission to retesting one week later were calculated and fell generally within the medium effect size range. There were no MCMI-III subscale differences between groups at either test time. A test item dealing with suicidal ideation did differentiate between the groups, with inpatients expressing more suicidal ideation at admission.

Adult↗

PubMed1997

MCMI-III as a treatment outcome measure for psychiatric inpatients.

The Million Clinical Multiaxial Inventory-III (MCMI-III) recently was introduced to replace and update the MCMI-II. A sample of 97 psychiatric inpatients were administered the MCMI-III shortly following admission, and again 7-10 days later. Changes in the personality and symptom scales generally paralleled those found in previous work with the MCMI-II, although the mean retest interval was considerably shorter than in the earlier study. However, some differences between the two instruments were observed, confirming the need for ongoing cross-validation work on the MCMI-III as an instrument that is distinct from the MCMI-II.

Adolescent↗

PubMed1997

Mutual information for automated unwarping of rat brain autoradiographs.

An automated multimodal warping based on mutual information metric (MI) as a mapping cost function is demonstrated. Mutual information (I) is calculated from a two-dimensional (2D) gray scale histogram of an image pair, and MI (= -I) provides a matching cost function which can be effective in registration of two- or three-dimensional data sets independent of modality. Most histological image data, though information rich and high resolution, present nonlinear deformations due to the specimen sectioning and need reconstitution into deformation-corrected volumes prior to geometric mapping to an anatomical volume for spatial analyses. Section alignment via automatic 2D registrations employing MI as a global cost function and thin-plate-spline (TPS) warping is applied to deoxy-D-[14C]glucose autoradiographic image slices of a rat brain with video reference images of the uncut block face to reconstitute a cerebral glucose metabolic volume data. Unlike the traditional feature-based TPS warping algorithms, initial control points are defined independently from feature landmarks. Registration quality using automated multimodal image warping is validated by comparing MIs of the image pair registered by automated affine registration and manual warping method. The MI proves to be a robust objective matching cost function effective for automatic multimodality warping for 2D data sets and can be readily applied to volume registrations.

Algorithms↗

PubMed1997

Ultrasonic characterization of in vitro osteoarthritic articular cartilage with validation by confocal microscopy.

The majority of adults over the age of 65 y develop osteoarthritis (OA), a joint disease characterized by degeneration of articular cartilage and subchondral sclerosis. Early in the disease, the articular cartilage surface begins to change histologically from a smooth to a rough or fibrillated appearance. A prerequisite for any chondroprotective pharmacological intervention is detection of OA in its preclinical phase. Current diagnostic imaging modalities, such as radiographs or (nuclear) magnetic resonance imaging, either cannot directly image the cartilage surface or lack sufficient resolution to detect surface fibrillations. We have developed an ultrasonic technique that can be used to characterize these surface fibrillations directly. We present our in vitro results with validation by laser-based confocal microscopic imaging.

Adult↗

PubMed1997

Demonstration of accuracy and clinical versatility of mutual information for automatic multimodality image fusion using affine and thin-plate spline warped geometric deformations.

This paper applies and evaluates an automatic mutual information-based registration algorithm across a broad spectrum of multimodal volume data sets. The algorithm requires little or no pre-processing, minimal user input and easily implements either affine, i.e. linear or thin-plate spline (TPS) warped registrations. We have evaluated the algorithm in phantom studies as well as in selected cases where few other algorithms could perform as well, if at all, to demonstrate the value of this new method. Pairs of multimodal gray-scale volume data sets were registered by iteratively changing registration parameters to maximize mutual information. Quantitative registration errors were assessed in registrations of a thorax phantom using PET/CT and in the National Library of Medicine's Visible Male using MRI T2-/T1-weighted acquisitions. Registrations of diverse clinical data sets were demonstrated including rotate-translate mapping of PET/MRI brain scans with significant missing data, full affine mapping of thoracic PET/CT and rotate-translate mapping of abdominal SPECT/CT. A five-point thin-plate spline (TPS) warped registration of thoracic PET/CT is also demonstrated. The registration algorithm converged in times ranging between 3.5 and 31 min for affine clinical registrations and 57 min for TPS warping. Mean error vector lengths for rotate-translate registrations were measured to be subvoxel in phantoms. More importantly the rotate-translate algorithm performs well even with missing data. The demonstrated clinical fusions are qualitatively excellent at all levels. We conclude that such automatic, rapid, robust algorithms significantly increase the likelihood that multimodality registrations will be routinely used to aid clinical diagnoses and post-therapeutic assessment in the near future.

Abdomen↗

PubMed1997

The GAF and psychiatric outcome: a descriptive report.

Since the Global Assessment of Functioning Scale (GAF) was introduced in DSM-III-R in 1987, it has been widely used, but minimally researched. This report provides information concerning the use of the GAF in routine clinical practice. Clinicians rated adult inpatients, adult day hospital patients, and adolescent inpatients at admission and discharge from psychiatric treatment. All samples were rated as significantly less dysfunctional at discharge. There were also significant differences in mean levels of dysfunction between the adult and adolescent samples at admission and discharge. These discrepancies were hypothesized to be associated with the GAFs unclear instructional format. Although this study concerned the GAF as described in the DSM-III-R, our findings are likely to be generalizable to DSM-IV, because no substantive changes have been made to the GAF.

Adolescent↗

PubMed1995

Agreement between patient self-report and clinician rating: concurrence between the BSI and the GAF among psychiatric inpatients.

Two rating scales were compared for 200 adult psychiatric inpatients at admission to, and discharge from, the hospital. Patients rated their own psychological symptoms on the Brief Symptom Inventory (BSI), and clinicians rated patients' psychological, social, and occupational functioning on the Global Assessment of Functioning (GAF) Scale. Analyses indicated no significant relationships between symptom distress reported by patients and global functioning rated by clinicians. These findings support previous research that has shown minimal congruence among criterion measures that differ in rating source.

Adolescent↗

PubMed1994

The Brief Symptom Inventory (BSI) as an outcome measure for adult psychiatric inpatients.

In this study the Brief Symptom Inventory (BSI; Derogatis & Spencer, 1982) was administered to 89 males and 128 females at admission and discharge from a private psychiatric hospital. For mean scores, statistically significant decreases were observed on all BSI scales and global indices. Effect sizes ranged from high medium to large. Also, when clinical significance indices were calculated with regard to changes made by individual patients, we found that approximately 50% of all inpatients evidenced a decrease on the Global Severity Index (GSI), which meets the dual criteria of significant change and posttreatment functioning in the normal range. Compared with inpatient norms (Derogatis & Spencer, 1982), our sample generally scored higher at admission and lower at discharge.

Adjustment Disorders↗

PubMed1994

Generating a normalized geometric liver model using warping.

RATIONALE AND OBJECTIVES: Automated liver surface determination in abdominal computed tomography scans, currently difficult to achieve, is of interest to determine liver location and size for various medical applications, including radiation therapy treatment planning, surgical planning, and oncologic monitoring. The authors propose to facilitate automation by the addition of a priori shape information in the form of a liver model. METHODS: The normalized geometric liver model is generated by averaging outlines from a set of normal liver studies previously registered using thin-plate spline warping. The model consists of an averaged liver surface, a set of anatomic landmarks, and a deformation function. RESULTS: A liver model is presented and its ability to represent normal liver shapes is demonstrated. CONCLUSIONS: Liver surface warping provides a means of data normalization for model construction and a means of model deformation for representation of liver organ shapes.

Computer Simulation↗

PubMed1994

Unidimensionality of the Brief Symptom Inventory (BSI) in adult and adolescent inpatients.

This study investigated the factor structure of the Brief Symptom Inventory (BSI; Derogatis, 1992) for adult and adolescent psychiatric inpatients. The BSI was administered to 217 adults and 188 adolescents at admission and discharge from a private psychiatric hospital. Principal components factor analyses revealed that most variance among dimension scores was accounted for by one unrotated factor. Factorial invariance was evident across adult and adolescent samples for admission and discharge scores. Our findings are consistent with previous research on the BSI and Symptom Checklist-90-R (Derogatis, 1977), suggesting that both instruments measure primarily a unidimensional construct of general psychological distress.

Adolescent↗

PubMed1991

Method for measuring three-dimensional motion with tagged MR imaging.

Recent methods of magnetic resonance imaging involve the placement of a grid of planes of saturation over the imaging plane; distortion of the grid corresponds to tissue displacement in two dimensions. An extension to this method that allows measurement of motion in the third dimension involves a second acquisition that tilts the grid, allowing analysis of motion normal to the imaging plane. A rotating phantom was used to verify the accuracy of the motion measurements, and the technique was applied to the heart wall and skeletal muscle. Phantom results show that the measure of z motion can be as accurate as that of x and y motion. Three-dimensional displacements of heart-wall and skeletal muscle are shown. With an accurate measure of three-dimensional motion, more complete analysis of heart-wall motion and contraction is possible.

Humans↗