MRI of the Knee Meniscus.

Menisci are small fibrocartilaginous structures that are essential for the knee stability and preservation of articular cartilage. This article discusses the anatomy and function, variations, appearance and consequence of tears, and postoperative evaluation. We also address pitfalls and signs which can help improve diagnostic accuracy.

Effectiveness of Hematoma Aspiration and Platelet-rich Plasma Muscle Injections for the Treatment of Hamstring Strains in Athletes.

INTRODUCTION: The effect of platelet-rich plasma (PRP) treatment on recovery in acute hamstring injuries is controversial. Previous study results are inconsistent, and a standardized therapeutic approach has not been established yet. PURPOSE: To assess the treatment effect using a combination of hematoma aspiration and muscle strain PRP injection in partial hamstring muscle tears (grade 2 strains) in athletes. METHODS: Magnetic resonance imaging of athletes with grade 2 hamstring strains were reviewed from 2013 to 2018. From 2013 to 2015, athletes were treated conservatively, and from 2016 to 2018, with a combination of ultrasound-guided hematoma aspiration and PRP muscle strain injection. The outcome, including return-to-play (in days) and recurrence rate, was compared retrospectively between both groups (conservative vs aspiration/PRP) using ANOVA and Fisher's exact test. There was no significant difference in age, type of sport, and muscle involvement (including injury grade/location, hamstring muscle type, and length/cross-sectional area of the strain). RESULTS: Fifty-five athletes (28 treated conservatively, 27 with hematoma aspiration/PRP injection) were included. Average return-to-play time (mean) was 32.4 d in the conservative group and 23.5 d in the aspiration/PRP group (P < 0.001). Recurrence rate of the hamstring strain was 28.6% (8/28) in the conservative treatment group and less than 4% (1/27) in the aspiration/PRP group (P = 0.025). CONCLUSIONS: Athletes with grade 2 hamstring strains treated with a combination of hematoma aspiration and PRP injection had a significantly shorter return-to-play and a lower recurrence rate compared with athletes receiving conservative treatment.

Imaging approach to COVID-19 associated pulmonary embolism.

The novel coronavirus disease-2019 (COVID-19) illness and deaths, caused by the severe acute respiratory syndrome coronavirus-2, continue to increase. Multiple reports highlight the thromboembolic complications, such as pulmonary embolism (PE), in COVID-19. Imaging plays an essential role in the diagnosis and management of COVID-19 patients with PE. There continues to be a rapid evolution of knowledge related to COVID-19 associated PE. This review summarises the current understanding of prevalence, pathophysiology, role of diagnostic imaging modalities, and management, including catheter-directed therapy for COVID-19 associated PE. It also describes infection control considerations for the radiology department while providing care for patients with COVID-19 associated PE.

Investigation of Radiation Dose Estimates and Image Quality Between Commercially Available Interventional Fluoroscopy Systems for Fluoroscopically Guided Interventional Procedures.

RATIONALE AND OBJECTIVES: To investigate differences in radiation dose and image quality for single-plane flat-panel-detector based interventional fluoroscopy systems from two vendors using phantom study and clinical procedures. MATERIALS AND METHODS: AlluraClarityIQ (Philips) and Artis Q (Siemens-Healthineers) interventional fluoroscopy systems were evaluated. Phantom study included comparison of system-reported air-kerma rates (AKR) for clinical protocols with simulated patient thicknesses (20-40 cm). Differences in system-reported radiation dose estimates, cumulative-air-kerma (CAK) and kerma-area-product (KAP), for different clinical procedures were investigated. Subset analysis investigated differences in CAK, KAP and other factors affecting radiation dose when the same patients underwent repeat embolization procedures performed by the same physician on the two different fluoroscopy systems. Two blinded interventional radiologists reviewed image-quality for these procedures using a five-point scale (1-5; 5-best) for five parameters. RESULTS: Phantom study revealed that air-kerma rates was significantly higher for Artis Q system for 30-40cm of simulated patient thicknesses (p < 0.05). Overall data analysis from 4381 clinical cases revealed significant differences in CAK and KAP for certain procedures (p < 0.05); with significantly lower values for AlluraClarityIQ systems (median CAK lower by: 29%-58%). Subset analysis with 40 patients undergoing repeat embolization procedures on both systems revealed that median CAK and KAP were significantly lower for AlluraClarityIQ systems (p < 0.02) by 45% and 31%, respectively. Image quality scores for AlluraClarityIQ systems were significantly greater (mean difference range for five parameters: 1.3-1.6; p < 0.005). CONCLUSION: Radiation dose and image quality differences were observed between AlluraClarityIQ and Artis Q systems. AlluraClarityIQ systems showed lower radiation utilization and an increase in subjective perception of image quality.

Hyperacute intracranial hemorrhage with extensive contrast extravasation and rapid hematoma expansion imaged at onset with magnetic resonance imaging.

Evaluation for intracranial hemorrhage is a common indication when performing imaging of the head in the emergency setting. We present a rare case of active, spontaneous extravasation of blood into the brain parenchyma, which evolved during a magnetic resonance imaging examination. A 70-year-old woman who had no previous history of hypertension or trauma underwent magnetic resonance imaging of the brain for confusion and dysarthria. Initial imaging sequences did not demonstrate an acute cerebral hemorrhage; however, subsequent fluid-attenuated inversion recovery, T2- and T1-weighted sequences demonstrated a progressively enlarging signal abnormality. Extravasation of contrast was noted after the administration of gadolinium-based contrast, indicating active intraparenchymal hemorrhage. A computed tomography scan was performed after magnetic resonance imaging to confirm the findings.

Biliary excretion of gadobenate dimeglumine causing degradation of magnetic resonance cholangiopancreatography (MRCP).

PURPOSE: To assess the effect of gadobenate dimeglumine on magnetic resonance cholangiopancreatography (MRCP) and determine an appropriate time frame for performing MRCP sequences. MATERIALS AND METHODS: 2D MRCP sequences obtained after intravenous administration of gadobenate dimeglumine or gadobutrol over 14 months were reviewed retrospectively in randomized order by five abdominal radiologists, using a 3-point scale to rate biliary and pancreatic duct clarity (1 = no-, 2 = limited-, 3 = good visualization). Intraclass correlation coefficients were computed and mean scores were compared for both agents. For gadobenate dimeglumine exams, time delays between arterial phase and MRCP acquisition times were analyzed concerning duct clarity. For gadobutrol, only exams with delays ≥ 15 min were included. RESULTS: 134 exams (107 gadobenate dimeglumine, 27 gadobutrol) were included. Moderate reliability for pancreatic duct visualization and excellent reliability for visualization of intrahepatic bile ducts and upper and lower extrahepatic bile ducts were noted. No difference in mean scores was noted for pancreatic duct visualization (p = 0.66). Bile duct segment scores were lower with gadobenate dimeglumine (mean: 2.1-2.6) compared with gadobutrol (mean: 2.8-2.9) (p ≤ 0.006). For gadobenate dimeglumine, visualization scores varied depending on the delay between the arterial phase and MRCP acquisition (p ≤ 0.047). Good visualization for all bile duct segments was noted with delays of 7.2-9.4 min (95% confidence interval; mean 8.3 min). CONCLUSION: Bile duct clarity degraded on MRCP images with an increasing delay following gadobenate dimeglumine injection. 2D MRCP, thus, should be performed within 7.2 min after obtaining the arterial phase sequence to ensure good visualization of the entire biliary system.

Osteoblastoma in the occipital bone: A case report of a rare tumor in the calvarium.

Osteoblastomas infrequently occur in the calvarium, displaying a preference for temporal and frontal bones when it does. We present an unusual case of a large, expansile osteoblastoma in the occipital bone of a 23-year-old man who presented with a nontender lump at the back of his head. Initial computed tomography scan showed a large occipital bone mass, and after additional imaging, a gross total resection was performed. Histopathological examination revealed an osteoblastoma. Although these tumors are benign, overlapping imaging characteristics of lesions affecting the calvarium often present a diagnostic dilemma. This case emphasizes the importance of imaging in the management and work-up of these patients to decrease the risk of complications and assists surgeons in their preoperative planning.