Diagnostic accuracy of imaging brain vesicular monoamine transporter type 2 (VMAT2) in clinically uncertain parkinsonian syndrome (CUPS): a 3-year follow-up study in community patients.

OBJECTIVES: To further validate the diagnostic utility of 18F-AV-133 vesicular monoamine transporter type 2 (VMAT2) positron emission tomography (PET) in patients with clinically uncertain parkinsonian syndromes (CUPS) by comparison to clinical diagnosis at 3 years follow-up. DESIGN, SETTING AND PARTICIPANTS: In a previous study, we reported that 18F-AV-133 PET in community patients with CUPS changed diagnosis and management and increased diagnostic confidence. The current diagnosis of this cohort was obtained from the patient and treating specialist and compared with the diagnosis suggested 3 years earlier by the 18F-AV-133 PET. A second 18F-AV-133 PET was available in those with a discordant or inconclusive final diagnosis. STUDY OUTCOME MEASURES: The primary end point was the proportion of patients who had a follow-up clinical diagnosis, which was concordant with their initial 18F-AV-133 PET scan. Secondary end points were the proportion of patients who had the same diagnosis at follow-up as that reached after the initial scan and the stability of diagnostic changes made after the first scan. RESULTS: 81 of the 85 patients previously recruited to the CUPS study had follow-up of which 79 had a clinical diagnosis and 2 remained CUPS. The diagnosis was in agreement with the initial 18F-AV-133 PET scan result in 74 cases. Five patients had a discordant diagnosis; one patient with rubral tremor had a severely abnormal scan that had worsened when rescanned; four cases with normal initial and repeat scans had a clinical diagnosis of Parkinson's disease. Two patients with suspected genetic disorders remained classified as CUPS and both had normal scans. In the 24 CUPS cohort patients where 18F-AV-133 PET initially changed diagnosis, this change was supported by follow-up diagnosis in all but the one rubral tremor case. CONCLUSION: 18F-AV-133 PET is a useful tool in improving diagnostic accuracy in CUPS providing results and diagnostic changes that remain robust after 3 years follow-up.

Management Impact of Imaging Brain Vesicular Monoamine Transporter Type 2 in Clinically Uncertain Parkinsonian Syndrome with 18F-AV133 and PET.

Idiopathic Parkinson disease is a common neurodegenerative disorder for which misdiagnosis occurs in up to 30% of patients after initial assessment and in 10%-15% even after long-term follow-up. Vesicular monoamine transporter type 2 (VMAT2) imaging with PET allows assessment of the integrity of the presynaptic dopaminergic pathway. We investigated the management impact of VMAT2 imaging in patients with clinically uncertain Parkinsonian syndromes. Methods: Forty-seven patients with clinically uncertain Parkinsonian syndromes (mean age ± SD, 56.9 ± 14.9 y; age range, 21-80 y) were referred from movement disorder specialists. All participants underwent a 20-min PET acquisition 2 h after injection of 250 MBq of 18F-AV-133, and the resulting images were quantitatively assessed. Clinical impact was recorded as high, moderate, or low based on diagnosis and management questionnaires completed by the referring specialists before and after release of the PET results. Management impact was high if there was a change in diagnostic category, moderate if there was a change in medication, and low if there was no change. Results: VMAT2 PET changed the diagnosis in 11 (23%) and medication in 25 (53%) participants. Management impact was high in 23%, moderate in 38%, and low in 39% of the participants. High diagnostic confidence increased from 11% of patients to 80% after the release of the scan results. Conclusion:18F-AV-133 had substantial management impact in patients with clinically uncertain Parkinsonian syndromes. VMAT2 imaging with 18F-AV133 might improve diagnosis, prognosis, and appropriate use of medication, translating into better patient outcomes.

Haemodynamic and biochemical responses to fluid bolus therapy with human albumin solution, 4% versus 20%, in critically ill adults.

BACKGROUND: Fluid bolus therapy (FBT) is common in critically ill patients. With the exception of use in patients with traumatic brain injury, FBT with human albumin solution (HAS) appears safe and perhaps superior in severe sepsis. OBJECTIVE: To determine the physiological effects of FBT with 4% v 20% HAS. DESIGN, SETTING AND PARTICIPANTS: A retrospective observational study of 202 critically ill patients receiving FBT with HAS in a tertiary intensive care unit between April 2012 and March 2013. METHODS: FBT was instituted with 4% or 20% HAS, according to clinician preference. MAIN OUTCOME MEASURES: We compared biochemical and haemodynamic data between groups at baseline and at 1, 2 and 4 hours after FBT. RESULTS: Patients who had received 20% HAS had more liver disease, a greater need for renal replacement therapy and higher Acute Physiology and Chronic Health Evaluation III scores on admission. Patients who had received 4% HAS received a median volume of 500 mL (interquartile range [IQR], 350-500 mL), compared with 100mL (IQR, 100- 200 mL) in the 20% HAS group (P < 0.0001); a median of 70 mmol v 10 mmol of sodium (P < 0.0001); and a median of 64 mmol v 2 mmol of chloride (P < 0.0001). There was a trend toward higher mean arterial pressures in the 20% group after FBT (78.2 mmHg v 76.4 mmHg, P = 0.03). There were no significant differences in the absolute or percentage change for any haemodynamic parameters. Serum biochemical test results were comparable with a non-significant signal of higher serum chloride and more negative base excess in patients receiving 4% HAS. CONCLUSIONS: Haemodynamically, FBT with 100mL of 20% HAS performs in an equivalent way to 500 mL of 4% HAS but delivers much less fluid, sodium and chloride.