The value of (18)F-fluoride PET/CT in the assessment of screw loosening in patients after intervertebral fusion stabilization.

PURPOSE: We evaluated (18)F-fluoride PET/CT for the diagnosis of screw loosening after intervertebral fusion stabilization and compared the results with those from functional radiography. METHODS: A group of 59 patients with pain in the region of previous intervertebral fusion stabilization and suspicion of implant instability due to screw loosening were investigated with (18)F-fluoride PET/CT and functional radiography, 30.1 ± 3.4 and 29.3 ± 3.2 months, respectively, after surgery. The criterion for loosening was increased focal uptake surrounding the screw entry point and shaft. SUVmax and SUVmean were measured in a region of interest (ROI) drawn around each screw (334 screws analysed). The final diagnosis was established by surgical exploration in 27 patients and clinical follow-up after intervertebral fusion stabilization in 32 patients. RESULTS: Of the 59 patients, 20 were proven positive for implant failure due to screw loosening and 39 were confirmed negative. The sensitivity, specificity and accuracy of (18)F-fluoride PET/CT were 75%, 97.4% and 89.8% in the patient-based analysis, and 45.6%, 100% and 80% in the screw-based analysis, respectively. The positive and negative predictive values were 93.8% and 100 % in the patient-based analysis, and 88.4 and 76% in the screw-based analysis, respectively. CT signs in PET/CT allowed screw breakage to be detected in three patients. SUVmax, SUVmean and SUVmax/SUVmean ratios in screw ROIs and respective values in reference regions were all found to be significantly different between screws positive for loosening (58 screws) and screws negative for loosening (276 screws). The ratio between SUVmax in screw ROIs and the values in reference regions was the most significant parameter for distinguishing screws positive and screws negative for loosening. CONCLUSION: (18)F-Fluoride PET/CT imaging is useful for the diagnosis of screw loosening in patients with persistent symptoms after intervertebral fusion stabilization.

The demise of Archbishop Wolf Dietrich--A historical note on a fatal status epilepticus documented at Salzburg in 1617.

INTRODUCTION: Wolf Dietrich of Raitenau (WD) ruled the archiepiscopal Salzburg from March 2nd 1587 to December 17th 1611. He was condemned by his successor Archbishop Markus Sittikus of Hohenems to spend his last years imprisoned at the Fortress Hohensalzburg, where he died on January 16th 1617. This historical note describes the causes of his death. MATERIALS AND METHODS: The original Latin handwriting, including the detailed medical history and the autopsy of the Archbishop's body performed by his personal physician, was analyzed in conjunction with historical handwritings provided by St. Peter's Abbey, Salzburg handwriting assigned to Markus Sittikus. RESULTS: Wolf Dietrich of Raitenau had his first well-documented left hemispheric stroke in winter 1604/05. He had palsy of his right arm, was unable to write, and, therefore, used a stamp instead of his signature until October 1605. After another stroke, right hemispheric in origin with persisting palsy of his left arm ["leva corporis pars iam pridem simili ex apoplectico assultu in paralysin resoluta"], he developed symptomatic epilepsy with recurring seizures ["epileptico insultu quo etiam alias correptus est"]. On January 15th 1617, he suffered from a secondarily generalized convulsive status epilepticus ["toto corpore convellitur epileptico insultu"] with stertorous breathing and distortion of his face ["spuma stertore insigni faciei perversione"] and was unconscious for 8h. He recovered from coma and showed dysphagia, buccofacial apraxia ["abolitam diglutiendi facultatem"], reversible speech disturbance ["accisa etiam verba loqui"], and left-sided hemiplegia ["leva corporis pars… immobilis prorsus est reddita"]. The following day, he had speech disturbances, and he died at noon. His autopsy showed large but intact liver ["hepar magnum sanum"] and heart ["cor magnum in quo lapsus nullus"]. There was intrapulmonal mucus ["pituita imbutus"], and part of the lungs adhered to its pleura. He had five kidney stones and a partly cirrhotic spleen. The cause of his death was assumed to be intracerebral ["causa mortis in capite requienda fuisset"]. DISCUSSION: The terminal suffering of Wolf Dietrich of Raitenau is the first witnessed case report on a fatal status epilepticus in Salzburg. Most likely, he suffered from vascular epilepsy due to a right hemispheric stroke, leading to status epilepticus with left-sided Todd's palsy and speech disturbances. An acute symptomatic etiology of this disease cannot be ruled out, as for religious reasons, the Archbishop's brain was not autopsied. CONCLUSION: Meticulous medical reporting including autopsy was already available in Salzburg in 1617, and the symptomatic etiology of epilepsy was diagnosed correctly. This article is part of a Special Issue entitled "Status Epilepticus".

Quantitative Analysis of Diffusion-Restricted Lesions in a Differential Diagnosis of Status Epilepticus and Acute Ischemic Stroke.

Background and Purpose: Distinction between acute ischemic stroke (AIS) and status epilepticus (SE) on MRI can be challenging as restricted diffusion may occur in both conditions. In this study, we aimed to test a tool, which could help in differentiating AIS from SE when restricted diffusion was present on MRI. Materials and Methods: In diffusion weighted imaging (DWI) with a b-value of 1,000 and apparent diffusion coefficient (ADC) maps, we compared the ratios of intensities of gray values of diffusion-restricted lesions to the healthy mirror side in patients with AIS and SE. Patients were recruited prospectively between February 2019 and October 2021. All patients underwent MRI and EEG within the first 48 h of symptom onset. Results: We identified 26 patients with SE and 164 patients with AIS. All patients had diffusion-restricted lesions with a hyperintensity in DWI and ADC signal decrease. Diffusion restriction was significantly more intense in patients with AIS as compared to patients with SE. The median ratios of intensities of gray values of diffusion-restricted lesions to the healthy mirror side for DWI were 1.42 (interquartile range [IQR] 1.32-1.47) in SE and 1.67 (IQR 1.49-1.90) in AIS (p < 0.001). ADC decrease was more significant in AIS as compared to SE with median ratios of 0.80 (IQR 0.72-0.89) vs. 0.61 (IQR 0.50-0.71), respectively (p < 0.001). A cutoff value for ratios of DWI signal was 1.495 with a sensitivity of 75% and a specificity of 85%. Values lower than 1.495 were more likely to be associated with SE and higher values were with AIS. A cutoff value for ADC ratios was 0.735 with a sensitivity of 73% and a specificity of 84%. Values lower than 0.735 were more likely to be associated with AIS and higher values were with SE. Conclusion: Diffusion restriction and ADC decrease were significantly more intense in patients with AIS as compared to SE. Therefore, quantitative analysis of diffusion restriction may be a helpful tool for differentiating between AIS and SE when restricted diffusion is present on MRI.

Checklist and Scoring System for the Assessment of Soft Tissue Preservation in CT Examinations of Human Mummies.

The purpose of this study was to develop a checklist for standardized assessment of soft tissue preservation in human mummies based on whole-body computed tomography examinations, and to add a scoring system to facilitate quantitative comparison of mummies. Computed tomography examinations of 23 mummies from the Capuchin Catacombs of Palermo, Sicily (17 adults, 6 children; 17 anthropogenically and 6 naturally mummified) and 7 mummies from the crypt of the Dominican Church of the Holy Spirit of Vilnius, Lithuania (5 adults, 2 children; all naturally mummified) were used to develop the checklist following previously published guidelines. The scoring system was developed by assigning equal scores for checkpoints with equivalent quality. The checklist was evaluated by intra- and inter-observer reliability. The finalized checklist was applied to compare the groups of anthropogenically and naturally mummified bodies. The finalized checklist contains 97 checkpoints and was divided into two main categories, "A. Soft Tissues of Head and Musculoskeletal System" and "B. Organs and Organ Systems", each including various subcategories. The complete checklist had an intra-observer reliability of 98% and an inter-observer reliability of 93%. Statistical comparison revealed significantly higher values in anthropogenically compared to naturally mummified bodies for the total score and for three subcategories. In conclusion, the developed checklist allows for a standardized assessment and documentation of soft tissue preservation in whole-body computed tomography examinations of human mummies. The scoring system facilitates a quantitative comparison of the soft tissue preservation status between single mummies or mummy collections.

Cerebral hypoperfusion during carotid artery stenosis can lead to cognitive deficits that may be independent of white matter lesion load.

Studies investigating cognitive impairment in stroke-free patients with carotid artery stenosis have led to inconsistent results. Furthermore, the pathophysiological mechanism leading to cognitive impairment remains unclear. Cerebral hypoperfusion and arterio-arterial microembolization are discussed. The aims of our study were (1) to delineate patterns of cognitive impairment in stroke-free patients with carotid artery stenosis and (2) to investigate if cognitive impairment is independent of white matter lesion load in brain MRI. We identified 212 (93 women, mean age 70.2) stroke free, non-demented patients, who were referred for carotid artery stenting or because of subjective cognitive impairment. All patients completed a neurocognitive test battery measuring verbal fluency, constructional praxis, figural memory, verbal short-term- and long-term-memory, verbal recognition memory, semantic processing, speed of cognitive processing and divided attention. Grade of maximum carotid artery stenosis was categorized into three groups (mild, moderate, or severe). White matter lesion load was graded using a visual rating scale. Cognitive test scores of groups with different grades of carotid artery stenosis were compared. Univariate regression analysis was used to measure the predictive value of carotid artery stenosis. Multivariate logistic regression analysis was performed when integrating carotid artery stenosis and white matter lesion load. Carotid artery stenosis negatively correlated with measures of verbal fluency, constructional praxis, verbal short-term-memory, semantic processing, speed of cognitive processing, and divided attention. After adjustment for white matter lesions, carotid artery stenosis did not independently predict divided attention. Significance persisted in all other cognitive domains. In our selected group of patients, a higher grade of carotid artery stenosis is associated with cognitive decline. This process is independent of white matter lesion load. Possible pathophysiological implications are discussed.