Effect of acute high-intensity interval exercise on a mouse model of doxorubicin-induced cardiotoxicity: a pilot study.

BACKGROUND: It is unknown whether high-intensity interval exercise (HIIE) may potentiate or attenuate the cardiotoxic effect of chemotherapy agents such as doxorubicin (DOX) when performed shortly after treatment. The study aimed to investigate the effect of acute HIIE on cardiac function and structure performed either 1, 2 or 3 days after DOX injection in an animal model. METHODS: Female C57bl/6 mice (n = 28), 70 days old, received a bolus 20 mg/kg intravenous tail vein DOX injection. Three exercise groups performed 1 HIIE session (16 sets of 1 min at 85-90% of peak running speed) at 1 (n = 7), 2 (n = 7), and 3 days (n = 8) following the DOX injection. A sedentary (SED) group of mice (n = 6) did not exercise. Animals underwent echocardiography under light anesthesia (isoflurane 0.5-1%) before and 7 days after the DOX injection. Animals were sacrificed on day 9 and hearts were collected for morphometric and histological analysis. RESULTS: Animals exercising on day 3 had the smallest pre-post reduction in left ventricular fractional shortening (LVFS) (MΔ= -1.7 ± 3.3; p = 0.406) and the SED group had the largest reduction (MΔ=-6.8 ± 7.5; p = 0.009). After reclassification of animals according to their exercise compliance (performing > 8/16 of high-intensity bouts), LVFS in compliant mice was unchanged over time (LVFS MΔ= -1.3 ± 5.6; p = 0.396) while non-compliant animals had a LVFS reduction similar to sedentary animals. There were no significant differences in myocardial histology between groups. CONCLUSIONS: In this pilot murine study, one single HIIE session did not exacerbate acute doxorubicin-induced cardiotoxicity. The timing of the HIIE session following DOX injection and the level of compliance to exercise could influence the negative impact of DOX on cardiac function.

Myocarditis Following COVID-19 Vaccination.

Myocarditis is an established but rare adverse event following administration of messenger RNA-based coronavirus disease 2019 (COVID-19) vaccines and is most common in male adolescents and young adults. Symptoms typically develop within a few days of vaccine administration. Most patients have mild abnormalities on cardiac imaging with rapid clinical improvement with standard treatment. However, longer term follow-up is needed to determine whether imaging abnormalities persist, to evaluate for adverse outcomes, and to understand the risk associated with subsequent vaccination. The purpose of the review is to evaluate the current literature related to myocarditis following COVID-19 vaccination, including the incidence, risk factors, clinical course, imaging findings, and proposed pathophysiologic mechanisms.

Cardiac Imaging in Myocarditis: Current Evidence and Future Directions.

Myocarditis is defined as a non-ischemic inflammatory disease of the myocardium. It remains a challenge to diagnose given non-specific symptoms and lack of specific blood biomarkers. Cardiac imaging plays an important role in the evaluation of myocarditis with unique strengths and limitations of different imaging modalities, including cardiac magnetic resonance imaging, echocardiography, cardiac computed tomography, and positron emission tomography. The purpose of this review is to discuss the strengths and limitations of various cardiac imaging techniques in the evaluation of myocarditis, review imaging findings in specific causes of myocarditis including COVID-19 and after vaccination, evaluate the role of imaging in differentiating myocarditis from potential mimics and differential considerations, identify current gaps in knowledge, and propose future directions.

Myocarditis Following COVID-19 Vaccination.

Myocarditis is an established but rare adverse event following administration of messenger RNA-based coronavirus disease 2019 (COVID-19) vaccines and is most common in male adolescents and young adults. Symptoms typically develop within a few days of vaccine administration. Most patients have mild abnormalities on cardiac imaging with rapid clinical improvement with standard treatment. However, longer term follow-up is needed to determine whether imaging abnormalities persist, to evaluate for adverse outcomes, and to understand the risk associated with subsequent vaccination. The purpose of the review is to evaluate the current literature related to myocarditis following COVID-19 vaccination, including the incidence, risk factors, clinical course, imaging findings, and proposed pathophysiologic mechanisms.

Mesenteric Lymph Node Recurrence of a Primary Colorectal Leiomyosarcoma.

Primary colorectal leiomyosarcoma is an excessively rare entity. It is associated with an aggressive behavior and typically favor hematogenous spread. The current standard of care is surgical resection. A 49-year-old patient presented with a 2-month history of fever. A PET-scan revealed a hypermetabolic mass in the transverse colon, and colonoscopy confirmed a tumor. A right hemicolectomy was performed. Histopathological diagnosis was of a leiomyosarcoma. Fourteen months after the surgery, a follow-up abdominal scan revealed a 2 cm mesenteric lymph node that was hypermetabolic on PET-scan. The mesenteric lymph node was resected and histopathology confirmed a leiomyosarcoma metastasis. This case opens the controversy on the management of rare lymph node recurrences in colorectal leiomyosarcoma.

Rapid head and neck tissue identification in thyroid and parathyroid surgery using optical coherence tomography.

BACKGROUND: Optical coherence tomography (OCT) is a noninvasive imaging modality that may reproduce the microarchitecture of tissues in real-time. This study examines whether OCT can render distinct images of thyroid, parathyroid glands, adipose tissue, and lymph nodes in both healthy and pathological states. METHODS: Twenty-seven patients undergoing thyroidectomy, parathyroidectomy, and/or neck dissection for thyroid cancer were recruited prospectively for imaging prior to histopathological analysis. RESULTS: Based on 122 imaged specimens, qualitative OCT descriptions were derived for healthy thyroid, parathyroid gland, adipose tissue, and lymph node. The frequencies at which distinguishing features were present for each tissue type were 88%, 83%, 100%, and 82%. OCT appearance of pathological specimens were also described. CONCLUSIONS: Healthy neck tissues have distinct OCT appearances, which could facilitate parathyroid identification during thyroidectomies. However, images of parathyroid adenomas could be confused with those of lymph nodes, and benign and malignant thyroid nodules could not be differentiated.