Imaging evaluation of COVID-19 in the emergency department.

PURPOSE: The purpose of this study is to elucidate the chest imaging findings of suspected COVID-19 patients presenting to the emergency department and the relationship with their demographics and RT-PCR testing results. METHODS: Patients presenting to the ED between March 12 and March 28, 2020, with symptoms suspicious for COVID-19 and subsequent CXR and/or CT exam were selected. Patients imaged for other reasons with findings suspicious for COVID-19 were also included. Demographics, laboratory test results, and history were extracted from the medical record. Descriptive statistics were used to explore the relationship between imaging and these factors. RESULTS: A total of 227 patients from the emergency department were analyzed (224 CXRs and 25 CTs). Of the 192 patients with COVID-19 results, 173 (90.1%) had COVID-19 RT-PCR (+). Abnormal imaging (CXR, 85.7% and/or CT, 100%) was noted in 155 (89.6%) of COVID-19 RT-PCR (+) cases. The most common imaging findings were mixed airspace/interstitial opacities (39.8%) on CXR and peripheral GGOs on CT (92%). The most common demographic were African Americans (76.8%). Furthermore, 97.1% of African Americans were RT-PCR (+) compared to 65.8% of Caucasians. CONCLUSION: We found a similar spectrum of thoracic imaging findings in COVID-19 patients as previous studies. The most common demographic were African Americans (76.8%). Furthermore, 97.1% of African Americans were RT-PCR (+) compared to 65.8% of Caucasians. Both CT and CXR can accurately identify COVID-19 pneumonitis in 89.6% of RT-PCR (+) cases, 89.5% of false negatives, and 72.7% of cases with no RT-PCR result.

Biomechanical properties of the repaired and non-repaired rat supraspinatus tendon in the acute postoperative period.

PURPOSE: The rat rotator cuff (RC) model is used to study RC pathology and potential treatment; however, native scar-mediated healing allows the rat RC to recover at 4-6 weeks but little is known about acute healing. This study characterized the properties of the repaired and non-repaired rat RC following surgical detachment. MATERIALS AND METHODS: Forty-eight rats underwent surgical RC detachment and received surgical repair (Repair) or left unrepaired (Defect) to either 12 or 19 days. Healthy controls were obtained from contralateral limbs. Biomechanical properties were assessed using stress relaxation and failure testing and mechanical modeling performed using quasilinear viscoelastic (QLV) and structurally based elastic models. Histology and micro-magnetic resonance imaging were used to qualitatively grade tendon-to-bone healing. RESULTS: Repair and Defect exhibited significantly inferior mechanical properties compared to Healthy at both time points. Repair had significant increases in peak, equilibrium, and ultimate stress, modulus, and stiffness and significant decreases in cross-sectional area, % relaxation, and QLV constant "C" between 12 and 19 days, whereas Defect showed no change. CONCLUSIONS: This study demonstrates acute differences in mechanical properties of the rat supraspinatus tendon in the presence and absence of surgical repair. Understanding the longitudinal recovery of mechanical properties can facilitate more accurate characterization of RC pathology or future treatments.

The effect of granulocyte-colony stimulating factor on rotator cuff healing after injury and repair.

BACKGROUND: The failure rate of tendon-bone healing after repair of rotator cuff tears remains high. A variety of biologic- and cell-based therapies aimed at improving rotator cuff healing have been investigated, and stem cell-based techniques have become increasingly more common. However, most studies have focused on the implantation of exogenous cells, which introduces higher risk and cost. We aimed to improve rotator cuff healing by inducing endogenous stem cell mobilization with systemic administration of granulocyte-colony stimulating factor (G-CSF). QUESTIONS/PURPOSES: We asked: (1) Does G-CSF administration increase local cellularity after acute rotator cuff repair? (2) Is there histologic evidence that G-CSF improved organization at the healing enthesis? (3) Does G-CSF administration improve biomechanical properties of the healing supraspinatus tendon-bone complex? (4) Are there micro-MRI-based observations indicating G-CSF-augmented tendon-bone healing? METHODS: After creation of full-thickness supraspinatus tendon defects with immediate repair, 52 rats were randomized to control or G-CSF-treated groups. G-CSF was administered for 5 days after repair and rats were euthanized at 12 or 19 postoperative days. Shoulders were subjected to micro-MR imaging, stress relaxation, and load-to-failure as well as blinded histologic and histomorphometric analyses. RESULTS: G-CSF-treated animals had significantly higher cellularity composite scores at 12 and 19 days compared with both control (12 days: 7.40 ± 1.14 [confidence interval {CI}, 5.98-8.81] versus 4.50 ± 0.57 [CI, 3.58-5.41], p = 0.038; 19 days: 8.00 ± 1.00 [CI, 6.75-9.24] versus 5.40 ± 0.89 [CI, 4.28-6.51], p = 0.023) and normal animals (12 days: p = 0.029; 19 days: p = 0.019). There was no significant difference between G-CSF-treated animals or control animals in ultimate stress (MPa) and strain, modulus (MPa), or yield stress (MPa) and strain at either 12 days (p = 1.000, p = 0.104, p = 1.000, p = 0.909, and p = 0.483, respectively) or 19 days (p = 0.999, p = 0.964, p = 1.000, p = 0.988, and p = 0.904, respectively). There was no difference in MRI score between G-CSF and control animals at either 12 days (2.7 ± 1.8 [CI, 1.08-4.24] versus 2.3 ± 1.8 [CI, 0.49-4.17], p = 0.623) or 19 days (2.5 ± 1.4 [CI, 1.05-3.94] versus 2.3 ± 1.5 [CI, 0.75-3.91], p = 0.737). G-CSF-treated animals exhibited significantly lower relative bone volume compared with normal animals in the entire humeral head (24.89 ± 3.80 [CI, 20.17-29.60) versus 32.50 ± 2.38 [CI, 29.99-35.01], p = 0.009) and at the supraspinatus insertion (25.67 ± 5.33 [CI, 19.04-32.29] versus 33.36 ± 1.69 [CI, 31.58-35.14], p = 0.027) at 12 days. Further analysis did not reveal any additional significant relationships with respect to regional bone volume or trabecular thickness between groups and time points (p > 0.05). CLINICAL RELEVANCE: Postoperative stem cell mobilization agents may be an effective way to enhance rotator cuff repair. Future studies regarding the kinetics of mobilization, the homing capacity of mobilized cells to injured tissues, and the ability of homing cells to participate in regenerative pathways are necessary.

Moderate sedation: what radiologists need to know.

OBJECTIVE: The number of procedures conducted within the radiology department using moderate sedation is rising. Anecdotal evidence suggests that there is an inconsistency in the education of radiology trainees regarding moderate sedation. CONCLUSION: The purpose of this article is to give an overview and concise summary of the use of moderate sedation as put forth by the American Society of Anesthesia, American College of Radiology, and Society of Interventional Radiology. In addition, we will review the commonly used medications for moderate sedation and their reversal agents.

Normal MR imaging anatomy of the thigh and leg.

Magnetic resonance (MR) imaging is the modality of choice for evaluating the soft tissues of the thigh and leg because of its superior soft tissue contrast resolution, multiplanar imaging capability, and lack of ionizing radiation. The superb image quality facilitates learning normal imaging anatomy, which ultimately forms the foundation of diagnostic interpretation. The purpose of this article is twofold: (1) depict normal MR anatomy throughout the thigh and leg using representative MR images, emphasizing a compartmental approach; and (2) describe and explain the rationale of standard imaging protocols.

Normal MR imaging anatomy of the knee.

Magnetic resonance (MR) imaging is the preferred imaging modality for evaluating internal derangement of the knee, due to its superior soft tissue contrast resolution, multiplanar imaging capability, and lack of ionizing radiation. The superb image quality facilitates learning of normal imaging anatomy and conceptualizing spatial relationships of anatomic structures, leading to improved understanding of pathologic processes, mechanisms of injury, and injury patterns, and ultimately increased diagnostic accuracy. This article depicts normal MR imaging anatomy and commonly encountered anatomic variants using representative MR images of the knee, and describes and explains the rationale of routine knee MR imaging protocol.

Normal magnetic resonance imaging anatomy of the ankle & foot.

This article discusses anatomic relationships, anatomic variants, and MRI protocols that pertain to the foot and ankle. MR images with detailed anatomic description form the cornerstone of this article. The superb image quality will facilitate learning normal imaging anatomy, as well as conceptualizing spatial relationships of anatomic structures.