Improving CPMG liver iron estimates with a T 1 -corrected proton density estimator.

PURPOSE: CPMG spin echo acquisitions are attractive for diagnosing and monitoring liver iron concentration in iron overload disorders due to their time efficiency and potential to reveal unique information about tissue iron distribution. Clinical adoption remains low due to the insensitivity of CPMG-based R 2 estimates to liver iron concentration (LIC) when common fitting techniques are applied. In this work, we demonstrate that the inclusion of a proton density estimator (PDE) derived from the CPMG acquisition increase the sensitivity of CPMG R 2 estimates to LIC in both simulated and in-vivo human data. THEORY AND METHODS: CPMG R 2 acquisitions from 50 clinically indicated MRI studies in patients with iron overload were analyzed with and without PDE constraints. Liver regions of interest were fit to monoexpontial and nonexponential signal decay equations. LIC by R 2 ∗ served as the reference standard. The observed calibration between CPMG R 2 values and LIC were compared to results predicted from a previously validated Monte Carlo model. RESULTS: The sensitivity of CPMG-derived R 2 triples when a proton density constraint is applied. When compared with R 2 ∗ -LIC estimates, both monoexponential and nonexponential models were unbiased but demonstrated broad 95% confidence intervals particularly for LIC values below 12 mg/g. Absolute error did not increase with LIC. CONCLUSION: A proton density constraint can increase the sensitivity of CPMG-based models to iron. CPMG acquisitions are time-efficient and could potentially improve the dynamic range of single spin echo techniques as well as providing insight into tissue iron distribution.

Pain Relief and the Opioid Crisis in the United States and Canada.

Opioid analgesics hijack the body's innate wellness machinery (eg, naloxone blocks the placebo effect) and alleviate both physical and emotional pain. Starting in the 1980s, marketing and advocacy created an opioid-centric pain relief strategy based on the idea that physicians undermanage pain and worry too much about addiction. The increase of prescription opioids in the ecosystem (along with a resurgence in heroin use) contributed to dependence, misuse, overdoses, and overdose deaths. Laws punishing undermanagement of pain from the opioid crisis combined with more recent laws punishing overprescription of opioids add to the difficulties orthopaedic surgeons have in managing the pain of surgery and acute injury. The substantial variation in pain intensity for nociception (actual or potential tissue damage) and the persistent use of opioids after healing is well established are both accounted for largely by psychosocial factors (stress, distress, and less effective coping strategies). When a patient has more pain than expected, surgeons should first rule out compartment syndrome and infection and then focus on a comprehensive team- and strategy-based approach that addresses these psychosocial factors.

Temporal relation of meniscal tear incidence, severity, and outcome scores in adolescents undergoing anterior cruciate ligament reconstruction.

PURPOSE: Anterior cruciate ligament (ACL) rupture is increasingly common in adolescents. Time between ACL rupture and surgical reconstruction, surgical wait time, is related to concurrent meniscal tear incidence and possibly tear pattern. This study defines the relationship between meniscal tear characteristics and surgical wait time in adolescents with ACL rupture. METHODS: One-hundred and twenty-one consecutive adolescent (median age 16.1 years, range 9-19 years) ACL rupture patients undergoing primary ACL reconstruction were studied. All had documented surgical wait time, preoperative and 6-month post-operative outcome (Lysholm and pedi-IKDC) scores, and intraoperative meniscus tear characteristics. Meniscal tear severity was graded according to the Lawrence and Anderson system: non-surgical: grade 1; reparable: grade 2-3; irreparable: grade 4-5. Significant tears were defined as at least grade 2. RESULTS: Average age at surgery was 16.1 years. 48.7 % had surgical wait time greater than 6 months. 42.5 % of menisci were torn. With surgical wait time <6 months, there were more lateral than medial tears (48 vs 21 %, p = 0.001). With surgical wait time >6 months, medial tear incidence increased (50 vs 21 %, p < 0.001), there were more significant tears (63 vs 42 %, OR 2.3, p = 0.02), and preoperative Lysholm and pedi-IKDC scores were lower (58 vs 74, p < 0.001; 52 vs 61, p < 0.007). Scores were lower in patients with meniscus tears (63.8 vs 69.3, n.s.; 53.9 vs 60.5, p = .04). Patients with public insurance had risks of surgical wait time greater than 3 months (OR 12.4, p < 0.001) and 6 months (OR 7.8, p < 0.001), and of a significant meniscus tear (OR 2.5, p = 0.03). Six-month post-operative pedi-IKDC scores improved more in meniscus tear patients (28.4 vs 21, p = 0.05). CONCLUSIONS: This study shows a significant increase in medial meniscal tear incidence, decrease in preoperative scores, and worse tear severity with surgical wait time >6 months. Public insurance was a risk factor for longer surgical wait time and meniscus tear.