Frequency encoding for simultaneous display of multimodality images.

An original method for simultaneous display of functional and anatomic images, based on frequency encoding (FE), merges color PET with T1-weighted MR brain images, and grayscale PET with multispectral color MR images. A comparison with two other methods reported in the literature for image fusion (averaging and intensity modulation techniques) was performed. Methods: For FE, the Fourier transform of the merged image was obtained summing the low frequencies of the PET image and the high frequencies of the MR image. For image averaging, the merged image was obtained as a weighted average of the intensities of the two images to be merged. For intensity modulation, the red, green and blue components of the color image were multiplied on a pixel- by-pixel basis by the grayscale image. A comparison of the performances of the three techniques was made by three independent observers assessing the conspicuity of specific MRI and PET information in the merged images. For evaluation purposes, images from seven patients and a computer-simulated MRI/PET phantom were used. Data were compared with a chi-square test applied to ranks. Results: For the depiction of MRI and PET information when merging color PET and T1-weighted MR images, FE was rated superior to intensity modulation and averaging techniques in a significant number of comparisons. For merging grayscale PET with multispectral color MR images, FE and intensity modulation were rated superior to image averaging in terms of both MRI and PET information. Conclusion: The data suggest that improved simultaneous evaluation of MRI and PET information can be achieved with a method based on FE

Risk Management in Magnetic Resonance: Failure Mode, Effects, and Criticality Analysis

The aim of the study was to perform a risk management procedure in "Magnetic Resonance Examination" process in order to identify the critical phases and sources of radiological errors and to identify potential improvement projects including procedures, tests, and checks to reduce the error occurrence risk. In this study we used the proactive analysis "Failure Mode Effects Criticality Analysis," a qualitative and quantitative risk management procedure; has calculated Priority Risk Index (PRI) for each activity of the process; have identified, on the PRI basis, the most critical activities and, for them, have defined improvement projects; and have recalculated the PRI after implementation of improvement projects for each activity. Time stop and audits are performed in order to control the new procedures. The results showed that the most critical tasks of "Magnetic Resonance Examination" process were the reception of the patient, the patient schedule drafting, the closing examination, and the organization of activities. Four improvement projects have been defined and executed. PRI evaluation after improvement projects implementation has shown that the risk decreased significantly following the implementation of procedures and controls defined in improvement projects, resulting in a reduction of the PRI between 43% and 100%

[Primary neuroectodermal tumor with unusual spinal cord localization. A case report].

Description of imaging findings (case report) of a spinal localization of a primary neuroectodermal tumo

Clinical impact of correlative [123I]-FP-CIT brain imaging and neurological findings in suspect Parkinson's disease.

Here we report our experience in a general hospital setting using [(123)I]-FP-CIT SPECT to diagnose patients with suspect Parkinson's disease (PD). MATERIALS AND METHODS: Thirty consecutive patients (19M, 11W, mean age: 61+/-13 years) were prospectively studied. Patients underwent MRI (27) at 1.5T or CT (3) when MRI was contraindicated, to rule out focal brain abnormalities. Motor and cognitive function were evaluated by neurologists with UPDRS and Hoehn e Yahr Scale. [(123)I]-FP-CIT striatal uptake, assessed with SPECT, was classified as normal, non-diagnostic, abnormal (unilateral or bilateral). Imaging results (SPECT+MRI) were correlated with the neurological findings. RESULTS: In 5 patients the [(123)I]-FP-CIT brain SPECT was normal, suggesting that their symptoms could be related to a benign disorder such as essential tremor. Two patients had non-diagnostic [(123)I]-FP-CIT brain SPECT, with MRI/CT findings compatible with subcortical cerebrovascular disease. In the remaining 23 patients abnormal striatal [(123)I]-FP-CIT uptake correlated with neurological findings, significantly increasing the probability of Parkinson's disease. In these patients MRI/CT scans were normal, or showed a mild BA, or mild cerebral vascular disease (mild CVD). CONCLUSIONS: Our results suggest that [(123)I]-FP-CIT scan could be used routinely in clinical practice to support the diagnosis of PD and to differentiate between other conditions. Moreover, FP-CIT could significantly impact treatment selection and follow-up of these patients

Reproducibility of intracranial volume measurement by unsupervised multispectral brain segmentation.

To assess the inter-study variability of a recently published unsupervised segmentation method (Magn. Reson. Med. 1997;37:84-93), 14 brain MR studies were performed in five normal subjects. Standard deviations for absolute and fractional volumes of intracranial compartments, which reflect the experimental variability, were smaller than 16.5 ml and 1.1%, respectively. By comparing the experimental component of the variability with the variability observed in our reference database, an estimate of the biological variability of the intracranial fractional volumes in the database population was obtaine