23Na chemical shift imaging in the living rat brain using a chemical shift agent, Tm[DOTP]5.

OBJECTIVE: It is well known that the use of shift reagents (SRs) in nuclear magnetic resonance (NMR) studies is substantially limited by an intact blood-brain barrier (BBB). The current study aims to develop a method enabling chemical shift imaging in the living rat brain under physiological conditions using an SR, Tm[DOTP]5-. MATERIALS AND METHODS: Hyperosmotic mannitol bolus injection followed by 60 min infusion of a Tm[DOTP]5- containing solution was administered via a catheter inserted into an internal carotid artery. We monitored the homeostasis of physiological parameters, and we measured the thulium content in brain tissue post mortem using total reflection fluorescence spectroscopy (T-XRF). The alterations of the 23Na resonance spectrum were followed in a 9.4T small animal scanner. RESULTS: Based on the T-XRF measurements, the thulium concentration was estimated at 2.3 ± 1.8 mM in the brain interstitial space. Spectroscopic imaging showed a split of the 23Na resonance peak which became visible 20 min after starting the infusion. Chemical shift imaging revealed a significant decrease of the initial intensity level to 0.915 ± 0.058 at the end of infusion. CONCLUSION: Our novel protocol showed bulk accumulation of Tm[DOTP]5- thus enabling separation of the extra-/intracellular 23Na signal components in the living rat brain while maintaining physiological homeostasis.

Lumbar Decompression versus Decompression and Fusion in Octogenarians: Complications and Clinical Course With 3-Year Follow-Up.

STUDY DESIGN: Retrospective review. OBJECTIVES: This study aimed to assess and compare the clinical course and complications between surgical decompression and decompression with fusion in lumbar spine patients aged ≥80 years. METHODS: A retrospective review of electronic medical records at a single institution was conducted between September 2005 and December 2021. Logistic regression was used to identify potential risk factors for the occurrence of complications. RESULTS: Over a 16-year period, 327 patients were allocated to the decompression only group and 89 patients were allocated to the decompression and instrumented fusion group. The study had a mean follow-up duration of 36.7 ± 12.4 months. When assessing the CCI, patients of the instrumentation group had fewer comorbidities (8.9 ± .5 points vs 6.2 ± 1.5 points; P < .001), significantly longer surgical duration (290 ± 106 minutes vs 145 ±50.2 minutes; P < .001), significantly higher volume of intraoperative blood loss (791 ± 319.3 ml vs 336.1 ± 150.8 ml; P < .001), more frequent intraoperative blood transfusion (7 ± 2.1% vs 16± 18.0%; P < .001), and extended stays in the intensive care unit and hospitalization rates. Logistic regression analysis revealed that surgical duration and extent of surgery were unique risk factors for the occurrence of complications. CONCLUSIONS: Lumbar decompression and additional fusion in octogenarians are considerable treatment techniques; albeit associated with increased complication risks. Prolonged operative time and extent of surgery are critical confounding factors associated with higher rates of postoperative complications. Surgery should only be performed after careful outweighing of potential benefits and risks.