Screening for Dementia Caused by Modifiable Lifestyle Choices Using Hybrid PET/MRI

Significant advances in positron emission tomography (PET) and magnetic resonance imaging (MRI) brain imaging in the early detection of dementia indicate that hybrid PET/MRI would be an effective tool to screen for dementia in the population living with lifestyle risk factors. Here we investigate the associated costs and benefits along with the needed imaging infrastructure. A demographic analysis determined the prevalence of dementia and its incidence. The expected value of the screening program was calculated assuming a sensitivity and specificity of 0.9, a prevalence of 0.1, a QALY factor of 0.348, a willingness to pay $114,000 CAD and the cost per PET/MRI scan of $2,000 CAD. It was assumed that each head PET/MRI could screen 3,000 individuals per year. The prevalence of dementia is increasing by almost two-fold every 20 years due to the increased population at ages where dementia is more prevalent. It has been shown that a five-year delay in the incidence of dementia would decrease the prevalence by some 45%. In Canada, a five-year delay corresponds to a health care savings of $27,000 CAD per subject per year. The expected value for screening was estimated at $23,745 CAD. The number of subjects to be screened per year in Canada, USA, and China between 60 and 79 was 11,405,000. The corresponding number of head-only hybrid PET/MRI systems needed is 3,800. A brain PET/MRI screening program is financially justifiable with respect to health care costs and justifies the continuing development of MRI compatible brain PET technology.

Grey matter and social functioning correlates of glutamatergic metabolite loss in schizophrenia

BACKGROUND

Thalamic glutamine loss and grey matter reduction suggest neurodegeneration in first-episode schizophrenia, but the duration is unknown.

AIMS

To observe glutamine and glutamate levels, grey matter volumes and social functioning in patients with schizophrenia followed to 80 months after diagnosis.

METHOD

Grey matter volumes and proton magnetic resonance spectroscopy metabolites in left anterior cingulate and left thalamus were measured in 17 patients with schizophrenia before medication and 10 and 80 months after diagnosis. Social functioning was assessed with the Life Skills Profile Rating Scale (LSPRS) at 80 months.

RESULTS

The sum of thalamic glutamate and glutamine levels decreased over 80 months, and correlated inversely with the LSPRS. Thalamic glutamine and grey matter loss were significantly correlated in frontal, parietal, temporal and limbic regions.

CONCLUSIONS

Brain metabolite loss is correlated with deteriorated social functioning and grey matter losses in schizophrenia, consistent with neurodegeneration.

MRI-identified abnormalities and wrist range of motion in asymptomatic versus symptomatic computer users

Background

Previous work has shown an association between restricted wrist range of motion (ROM) and upper extremity musculoskeletal disorders in computer users. We compared the prevalence of MRI-identified wrist abnormalities and wrist ROM between asymptomatic and symptomatic computer users.

Methods

MR images at 1.5 T of both wrists were obtained from 10 asymptomatic controls (8 F, 2 M) and 14 computer users (10 F, 4 M) with chronic wrist pain (10 bilateral; 4 right-side). Maximum wrist range of motion in flexion and radioulnar deviation was measured with an electrogoniometer.

Results

Extraosseous ganglia were identified in 66.6% of asymptomatic wrists and in 75% of symptomatic wrists. Intraosseous ganglia were identified in 45.8% of asymptomatic wrists and in 75% of symptomatic wrists, and were significantly (p < .05) larger in the symptomatic wrists. Distal ECU tendon instability was identified in 58.4% of both asymptomatic and symptomatic wrists. Dominant wrist flexion was significantly greater in the asymptomatic group (68.8 ± 6.7 deg.) compared to the symptomatic group (60.7 ± 7.3 deg.), p < .01. There was no significant correlation between wrist flexion and intraosseous ganglion burden (p = .09)

Conclusions

This appears to be the first MRI study of wrist abnormalities in computer users.

This study demonstrates that a variety of wrist abnormalities are common in computer users and that only intraosseous ganglia prevalence and size differed between asymptomatic and symptomatic wrists. Flexion was restricted in the dominant wrist of the symptomatic group, but the correlation between wrist flexion and intraosseous ganglion burden did not reach significance. Flexion restriction may be an indicator of increased joint loading, and identifying the cause may help to guide preventive and therapeutic interventions.

Multimodality imaging of early heterotopic bone formation

An atypical heterotopic bone formation that was difficult to diagnose presented in a young paraplegic patient as an acute deep vein thrombosis. A number of imaging methods, including contrast venography, ultrasonography, conventional radiography, bone scanning, leukocyte scanning, computed tomography, and magnetic resonance imaging, were used to arrive eventually at the final diagnosis. Early bone scanning remains a sensitive and effective method of diagnosis. Computed tomography can be useful in difficult cases, but the role of other imaging studies appears limited.

Cerebral perfusion imaging with technetium-99m HM-PAO in brain death and severe central nervous system injury

We performed 38 cerebral perfusion studies in 33 patients with brain death or with severe central nervous system injury using technetium-99m hexamethyl-propyleneamine oxime [( 99mTc]HM-PAO). Uptake by the cerebrum and/or cerebellium was present in all patients who were not clinically brain dead (ten studies) although the study was often abnormal. In those patients who were brain dead, 16/17 studies demonstrated no uptake in either the cerebrum or cerebellum. In patients suspected of brain death, but who had conditions interfering with the diagnosis the test demonstrated no uptake in 9/11 studies, confirming brain death. A radionuclide angiogram (RNA) of the head was also performed in 33/38 studies and showed complete agreement with the [99mTc]HM-PAO uptake, except in one case. We conclude that cerebral perfusion imaging with [99mTc]HM-PAO is a simple, noninvasive and reliable test to confirm brain death. By comparison with conventional technetium agents, [99mTc]HM-PAO is not dependent on the quality of the bolus injection, is easier to interpret and allows evaluation of posterior fossa blood flow.