Aims: To estimate the long term cost effectiveness of treatment for amblyopia in 3 year old children. Methods: A cost utility analysis was performed using decision analysis including a Markov state transition model. Incremental costs and effects during the children’s remaining lifetime were estimated. The model took into account the costs and success rate of treatment as well as effects of unilateral and bilateral visual impairment caused by amblyopia and other eye diseases coming along later in life on quality of life (utility). Model parameter values were obtained from the literature, and from a survey of experts. For the utility of unilateral visual impairment a base value of 0.96 was assumed. Costs were estimated from a third party payer perspective for the year 2002 in Germany. Costs and effects were discounted at 3%. Uncertainty was assessed by univariate and probabilistic sensitivity analysis (Monte-Carlo simulation). Results: The incremental cost effectiveness ratio (ICER) of treatment was €2369 per quality adjusted life year (QALY). In univariate sensitivity analysis the ICER was most sensitive to uncertainty concerning the utility of unilateral visual impairment—for example, if this utility was 0.99, the ICER would be €9148/QALY. Monte-Carlo simulation yielded a 95% uncertainty interval for the ICER of €710/QALY to €38 696/QALY; the probability of an ICER smaller than €20 000/QALY was 95%. Conclusion: Treatment for amblyopia is likely to be very cost effective. Much of the uncertainty in results comes from the uncertainty regarding the effect of amblyopia on quality of life. In order to reduce this uncertainty the impact of amblyopia on utility should be investigated.

Background/Objectives: Fabry disease (FD) is a rare X-linked lysosomal storage disorder characterised by progressive glycolipid accumulation affecting multiple organs, including the peripheral nervous system. The dorsal root ganglia (DRG) play a key role in Fabry-related neuropathy, but non-invasive biomarkers of DRG involvement and their association with overall disease severity remain limited. This study evaluated lumbosacral DRG T2 relaxation time (DRG-T2) in FD patients as a potential imaging biomarker of FD severity. Methods: In a prospective, single-centre study, 80 genetically confirmed FD patients underwent 3T MRI with quantitative T2 mapping of the lumbosacral DRG. DRG-T2 was analysed in relation to sex, genetic subtype and Fabry-specific biomarkers. Results: Results showed that DRG-T2 was higher in patients with classical FD mutations than in those with nonclassical mutations (p = 0.03). Furthermore, DRG-T2 showed a negative correlation with body weight (ρ = −0.31, p = 0.005) and BMI (ρ = −0.32, p = 0.004), while no associations were found with lyso-Gb3 levels or alpha-galactosidase A activity. The inter-rater and test–retest reliability of DRG-T2 were good to excellent (ICC = 0.76 and 0.89, respectively). Conclusions: These results demonstrate DRG-T2 as a marker of neuronal involvement, making it a strong and reliable imaging biomarker of disease severity in FD. However, future studies need to correlate its changes with clinical and histological studies.

Dorsal root ganglia (DRG) of the peripheral nervous system (PNS) transmit information from inside and outside the body to the central nervous system (CNS). The DRG's unique multicellular unit of neurons, endothelial cells, satellite glial and immune cells undergoes remarkable changes after nerve injury and in neuropathic pain conditions and is a target for local and systemic pain therapies. DRG-magnetic resonance imaging (DRG-MRI) visualizes structural DRG injury in various neuropathic pain syndromes and has become a promising tool for detection and monitoring of DRG-pathology in humans. Here, we provide novel insights for murine DRG-MRI by applying MR-microscopy and high field MR-sequences optimized for DRG visualization and DRG-volumetry. We characterize murine DRG-volume (DRG_vol) as level specific for the lumbar levels L2 < L3 < L4 (p < 0.001) and positively correlated to height (p < 0.001), age (p < 0.001) and weight (p < 0.05) but independent of sex in a cohort of 24 wildtype mice. In a proof of principle experiment we report DRG-enlargement by up to 30 % in an α-galactosidase A deficient mouse model of Fabry disease (p < 0.01). Finally, we demonstrate the DRG's high microvascular perfusion compared to muscle and spinal cord in dynamic contrast enhanced MRI in a subcohort of six wildtype mice. DRG-MRI is a promising non-invasive imaging method, applicable not only to humans but also to rodent models, which are frequently utilized in pain research. The parallel use of DRG-MRI in humans and rodents can enhance comparability and translatability in preclinical and clinical pain research thoroughly.

Background/Objectives: Fabry disease (FD) is a lysosomal storage disorder often associated with early-onset neuropathic pain, attributed to small fibre neuropathy (SFN). The dorsal root ganglion (DRG) has emerged as a critical site of early pathophysiological involvement in FD, with structural and functional alterations implicated in the development of neuropathic symptoms. This exploratory study introduces DRG proton density (DRG-PD) as a novel MRI-derived biomarker and evaluates its association with SFN. Methods: Eighty genetically confirmed FD patients underwent high-resolution 3T MRI with DRG-PD quantification at the lumbosacral levels L5 and S1. DRG-PD was derived from B1-corrected multi-echo spin echo sequences and normalised to cerebrospinal fluid intensity. All patients underwent clinical, biochemical and histological evaluation to determine SFN status. Associations between DRG imaging parameters and clinical variables were analysed using correlation and regression models. Diagnostic performance was evaluated using receiver operating characteristic curve analysis. Results: DRG-PD values were significantly increased in patients with classical FD and SFN, demonstrating a large effect size (Cliff’s δ = 0.92) and excellent discriminatory performance (AUC = 0.96). In contrast, DRG volume and T2 relaxation time were not significantly associated with SFN status. DRG-PD remained an independent predictor of SFN in multivariable logistic regression (p = 0.019). Conclusions: DRG-PD is a non-invasive correlate of SFN in classical FD. It may provide superior diagnostic value compared to existing MRI metrics and reflects proximal ganglionic pathology not captured by distal histological assessments.

Background/Objectives: Dorsal root ganglion (DRG) enlargement in radiculopathy reflects inflammatory nerve root responses and correlates with symptom severity. While DRG enlargement can be detected by MRI, it is unclear whether photon-counting detector CT (PCD-CT) acquired during routine periradicular therapy (PRT) enables detection and quantification of DRG volumetric changes in lumbosacral radiculopathy. Methods: This retrospective study included 28 selected patients with unilateral L5 or S1 radiculopathy undergoing PCD-CT-guided PRT followed by confirmed therapeutic response. Three independent blinded readers segmented DRGs on low-dose planning acquisitions. Affected and contralateral DRG volumes were compared using paired Wilcoxon signed-rank tests. Results: Affected DRGs exceeded contralateral volumes in 26 of 28 patients (92.9%). Median symptomatic DRG volume was 341.1 mm³ versus 282.3 mm³ contralaterally (p < 0.001). Median DRG enlargement was +24.0%. The result was consistent across L5 and S1 radiculopathy levels. Inter-reader agreements were high (median Dice similarity coefficients 0.78–0.85, median volumetric similarities 0.93–0.95). Conclusions: PCD-CT enables visualization and quantification of DRG volumetric changes on routine therapeutic imaging of selected patients, extracting biological information from procedural acquisitions. This establishes PCD-CT for investigating nerve pathophysiology and extends CT-based neuroradiological research into biological questions previously limited to MRI.