Quantification of myocardial fibrosis using noninvasive T2-mapping magnetic resonance imaging: Preclinical models of aging and pressure overload

Noninvasive imaging of cardiac fibrosis is important for early diagnosis and intervention in chronic heart diseases. Here, we investigated whether noninvasive, contrast agent-free MRI T₂-mapping can quantify myocardial fibrosis in preclinical models of aging and pressure overload. Myocardial fibrosis and remodeling were analyzed in two animal models: (i) aging (15-month-old male CF-1 mice vs. young 6- to 8-week-old mice), and (ii) pressure overload (PO; by transverse aortic constriction in 4- to 5-month-old male C57BL/6 mice vs. sham-operated for 14 days). In vivo T₂-mapping was performed by acquiring data during the isovolumic and early diastolic phases, with a modified respiratory and ECG-triggered multiecho TurboRARE sequence on a 7-T MRI. Cine MRI provided cardiac morphology and function. A quantitative segmentation method was developed to analyze the in vivo T₂-maps of hearts at midventricle, apex, and basal regions. The cardiac fibrosis area was analyzed ex vivo by picro sirius red (PSR) staining. Both aged and pressure-overloaded hearts developed significant myocardial contractile dysfunction, cardiac hypertrophy, and interstitial fibrosis. The aged mice had two phenotypes, fibrotic and mild-fibrotic. Notably, the aged fibrotic subgroup and the PO mice showed a marked decrease in T₂ relaxation times (25.3 ± 0.6 in aged vs. 29.9 ± 0.7 ms in young mice, p = 0.002; and 24.3 ± 1.7 in PO vs. 28.7 ± 0.7 ms in shams, p = 0.05). However, no significant difference in T₂ was detected between the aged mild-fibrotic subgroup and the young mice. Accordingly, an inverse correlation between myocardial fibrosis percentage (FP) and T₂ relaxation time was derived (R² = 0.98): T₂ (ms) = 30.45 – 1.05 × FP. Thus, these results demonstrate a statistical agreement between T₂-map–quantified fibrosis and PSR staining in two different clinically relevant animal models. In conclusion, T₂-mapping MRI is a promising noninvasive contrast agent-free quantitative technique to characterize myocardial fibrosis.     

Update on sports imaging

Sports Imaging has dramatically increased in the past decade with increasing number of adolescents, young and middle-aged adults participating in non-competitive/hobby sports. Therefore, sports injuries are no longer confined to elite athletes. Furthermore, newer forms of sports such as mountain climbing, pickle ball and curling etc. are gaining popularity. Majority of the injuries in sports medicine are from musculoskeletal trauma. Therefore, it is imperative that the musculoskeletal radiologist becomes familiar with various sports related injury patterns as these are commonly encountered in daily practice. This update aims to briefly encapsulate the major aspects of sports imaging. It includes the imaging manifestations of various types of musculoskeletal injuries on different modalities (commonly US and MRI) and briefly mentions the various image guided interventions, performed both on the sports field and in the hospital setting.     

Assessing Antibiotic Adherence and Improving Antibiotic Stewardship in Common Interventional Radiology Procedures

PurposeIn 2018, The Journal of Vascular and Interventional Radiology (JVIR) updated its guidelines regarding periprocedural antibiotics. However, some institutions are slower to adopt these new guidelines. Additionally, antibiotic-resistant bacteria and sepsis are serious concerns due in part to incorrect usage of antibiotics. The purpose of this study is to assess institutional adherence to 2018 JVIR guidelines for the purpose of improving antibiotic stewardship.Materials and methodsA total of 800 cases over a 10-month time period were retrospectively identified and charted following the release of guidelines. Inclusion criteria for the study were adults aged 21 years or older undergoing mediport placement, tunneled central line (TCL) placement, nephrostomy tube exchange, percutaneous biliary drain, or cholecystostomy tube exchange. Exclusion criteria included immunocompromised and pregnant individuals as 2018 guidelines may not fit these patient populations. Guideline adherence for each procedure was recorded as a percentage; the timing of the antibiotic usage was also recorded and compared to the guidelines (within 60 minutes before incision).ResultsIn total, 49 mediport placements, 118 tunneled central line placements – 44 hemodialysis (HD) catheters and 74 nonhemodialysis (non-HD) catheters, 100 nephrostomy exchanges, and 82 biliary tube exchanges were included. Antibiotics were used in 83.6% (41/49) of mediport patients, 11.3% (5/44) of non-HD TCL patients, 20.5% (15/74) of HD TCL patients, 55% (55/100) nephrostomy tube changes, and 65.4% (55/84) of biliary or cholecystostomy tube exchanges. Out of those given prophylaxis, guideline-recommended antibiotics were used in 100% (41/41) of mediport, 100% (20/20) of TCL (both HD and non-HD catheters), 9% (5/55) of nephrostomy tube exchanges, and 1.8% (1/55) of biliary tube exchanges. Guideline-recommended timing was followed in 75.3% across all cases (ranging from 72.2% in mediports to 79.3% in biliary exchanges).ConclusionThis study of antibiotic practices at a single university-based academic institution revealed that antibiotic usage is not fully up to date with 2018 guidelines. For mediports, non-HD TCL placements, and nephrostomy tube exchanges, institutional changes should be made to reduce periprocedural antibiotic use, as antibiotics are no longer recommended for these procedures. For HD TCL and biliary exchanges, proper adherence to recommended prophylactic antibiotics should be followed. In addition, education about the correct antibiotic timing should be emphasized to increase compliance with guidelines.     

Endolymph magnetic resonance imaging: Contribution of saccule and utricle analysis in the management of patients with sensorineural ear disorders

Endolymphatic hydrops features excess endolymph in the membranous labyrinth, and is a marker of Menière's disease. Between the early 1980s and late 2000s, MRI in Menière's disease aimed purely to rule out tumor or malformation as differential diagnoses for the pressure disorder. Progress in high-resolution MRI, however, now enables excess endolymph to be visualized in the membranous labyrinth, differentiating saccule and utricle in Menière's disease and in other clinical presentations such as cochleovestibular schwannoma. More recently, non-visibility of the saccule was demonstrated in a subgroup of Menière's disease patients, and utricle atelectasis in case of uni- or bilateral vestibular areflexia. Endolymph quantification remains highly controversial in terms of grading approach, but a simple semiology based on excess or deficient visualization of endolymph according to the compartment sheds light on the pathophysiological mechanisms of cochleovestibular disorder and may in future allow effective monitoring of medical and surgical treatment.