Short term vs. long term test–retest reproducibility of I-ADAM for the binding of serotonin transporters in the human brain

Previous brain imaging studies have demonstrated a seasonal difference of serotonin transporter (SERT) binding in the human brain. However, the results were somewhat contradictory. We conducted test–retest study with single photon emission computed tomography (SPECT) with ¹²³I-ADAM as ligand in 28 healthy subjects. Ten of the subjects were studied within 1 month, whereas 18 were randomly assigned to be studied over a period of up to 1 year. The primary measure was the specific uptake ratio (SUR). Regions of interest included the midbrain, thalamus, putamen and caudate. The intra-class correlation coefficient (ICC) was 0.52–0.94 across different brain regions over 1 month, whereas the ICC was - 0.24 – 0.63 over a 1 -year period. The 1 -month variability ranged from 6.5 ± 5.1% to 12.5 ± 10.6% across different brain regions, and the 1 -year variability ranged from 16.5 ± 9.6% to 41.9 ± 35.5%. The Kruskal–Wallis test revealed a significant difference of variability across months. The Wilcoxon Signed Ranks Test showed the SUR between test-retest scans was of borderline significance. Curve fitting, using a 4th degree polynomial model, revealed a significant circadian correlation between the variability and interval of test-retest measurements. Our findings demonstrate the test–retest reproducibility of ¹²³I-ADAM in different time periods and suggest that circadian variation of SERT levels in the human brain might exist.     

MR imaging of giant intracranial aneurysm.

We reviewed the clinical features and findings of magnetic resonance imaging (MRI) in 17 cases of giant intracranial aneurysm (GIA). All were confirmed by digital subtraction angiography (DSA). Seven were non-thrombosed and 10 were partially thrombosed.All thrombosed parts showed no enhancement. The majority of the lumen showed good enhancement in the post-contrast study (89%). About 80% of the partially thrombosed aneurysms had an onion skin appearance on non-contrast T1WI. On T2WI about 80% of partially thrombosed aneurysms had a low signal inside the thrombus or its wall from the susceptibility effect of blood elements such as haemosiderin. Flow void sign was noted in 88% on non-contrast T1WI and T2WI. Flow artifacts along the phase-encoding direction from the lumen of the aneurysm were noted in 41% of non-contrast T1WI, 56% of contrast-enhanced T1WI, and 29% of T2WI.Non-enhancement inside the thrombus and an onion skin appearance were important signs of thrombosis of the aneurysm. Flow artifacts along the phase-encoding direction from the lumen of the aneurysm provided an important clue of a patent lumen inside an aneurysm. The following signs provided clues to the diagnosis of patency lumen instead of thrombosis with high sensitivity and specificity: flow void sign on noncontrast T1WI (sensitivity 88%, specificity 100%), enhancement on contrast-enhanced T1WI (sensitivity 89%, specificity 100%), presence of either flow void sign or enhancement on contrast-enhanced T1WI (sensitivity 100%, specificity 100%).     

Posterior cranial fossa tumours in childhood

We reviewed clinical and CT findings in 133 posterior cranial fossa tumours in children. All had histological diagnosis, apart from 20 cases of brain stem glioma. The majority were intra-axial tumours, including 53 medulloblastomas (40%), 31 cerebellar astrocytomas (23%), 28 brain stem gliomas (21%), 14 ependymomas (11%), and single cases of ganglioglioma, haemangioblastoma and teratoma. Extra-axial tumours formed only 3%, including 2 chordomas and 2 schwannomas. The clinical data and CT findings are reviewed. Cerebellar astrocytoma involved the sexes equally, while medulloblastoma, brain stem glioma, and ependymoma were more common in males. Most cerebellar astrocytomas were in the midline, and presumably arose from the vermis. The frequency of calcification was similar to that in previous reports, being highest in ependymoma (69%), followed my medulloblastoma (29%), cerebellar astrocytoma (17%), and brain stem glioma (8%).     

Endovascular embolization of recurrent traumatic carotid-cavernous fistulas managed previously with detachable balloons

BACKGROUND: This study investigated the causes of recurrent traumatic carotid-cavernous fistulas (RTCCFs) after detachable balloon embolization and evaluated the selection of embolic materials for endovascular treatment of the RTCCFs. METHODS: Over a 10-year period, 116 patients underwent transarterial balloon embolization with occlusion of the fistulas and preservation of the parent arteries. In 15 patients, 18 RTCCFs developed. The causes of RTCCFs included premature balloon deflation and migration (n = 13) or bony fragment puncture of balloons (n = 5). A second or third embolization involved balloons (n = 6), balloons with coils (n = 2), and N-butyl-2-cyanoacrylate with coils (n = 7), or balloon, coils, and N-butyl-2-cyanoacrylate (n = 3). RESULTS: In this study, 17 RTCCFs were successfully occluded after repeat embolization with preservation of parent arteries. One case resulted in recurrent epistaxis. The recurrent fistula and parent artery were occluded with balloons. No significant complications or recurrent fistulas occurred after the last embolization (mean follow-up period, 16 months). CONCLUSIONS: Balloon puncture or premature deflation and migration occasionally cause RTCCFs. Sacrifice of the parent artery rarely is needed. Transarterial embolization remains the best approach, with balloons used first, then coils, N-butyl-2-cyanoacrylate, or both.     

Neuroradiological findings in atypical teratoid/rhabdoid tumor of the central nervous system

PURPOSE: To evaluate the computed tomography (CT) and magnetic resonance imaging (MRI) findings of atypical teratoid tumor/rhabdoid tumor (AT/RT) of the central nervous system (CNS). MATERIAL AND METHODS: Twenty cases of CNS AT/RT have been found over the past 23 years in our hospital; these involving 11 boys and 9 girls whose mean age at diagnosis was 5.5 years. Their clinical data, the CT, and MRI findings were reviewed retrospectively. RESULTS: AT/RT was located in the cerebellum in 15 cases. Four cases arose from the supratentorial region, while only one occurred primarily in the lumbar spinal cord. Almost all cases revealed heterogeneous intensity and heterogeneous enhancement. Peripheral cystic components were common. Survival time ranged from 2 months to 3 years, with a mean survival of 11.6 months. CONCLUSION: Most cases of AT/RT are located in the cerebellum. The radiologic manifestations are non-specific. The diagnosis mainly depends on the pathologic findings. However, AT/RT should still remain in the differential diagnosis of brain tumors in young children, especially those located in the cerebellar hemisphere and with eccentric cysts.     

Repetitive phenomena in dementia

OBJECTIVE: Both repetitive talk and behaviors (repetitive phenomena) are common in demented patients and are bothersome to their caregivers and families. The purpose of this preliminary report was to explore these repetitive phenomena in demented patients admitted to a geropsychiatric ward. METHOD: The sample population consisted of 141 demented patients. Patients' caregivers were asked if patients had presented a repetitive fixed pattern of physical action or talk since the onset of dementia. RESULTS: Of the 141 demented patients included in the study, seventy-nine had repetitive phenomena. Patients with these phenomena had various presentations and developed them in the early stage of dementia. CONCLUSIONS: Repetitive phenomena are widespread in dementia, especially for older patients, and may be an early sign of dementia. The characteristics of repetitive phenomena and some likely underlying mechanisms are discussed.