The influence of a meniscal bucket handle tear on the Posterior Cruciate Ligament Angle in Anterior Cruciate Ligament Rupture - A case report.

INTRODUCTION: Chronic anterior cruciate ligament (ACL) tear might be difficult to diagnose on MRI. Indirect signs might be a typical meniscal or cartilage lesion, or a spontaneous anterior drawer visualized by a decreased angle of the posterior cruciate ligament (PCL). PRESENTATION OF CASE: A 27-year-old former ballet dancer was admitted to the emergency department for a locked left knee, without never having experienced previous symptoms of giving way or locking. The MRI performed revealed a medial meniscus bucket handle tear, without traumatic bone marrow oedema or ligament injury. The PCL angle was 130°. A former MRI of her left knee performed 1 year previously to investigate on the recurrent catching of her left knee showed a grade III medial meniscal tear of the posterior horn, and buckling of the PCL angle of 100°, as a sign of chronic ACL rupture. During arthroscopy and medial meniscal repair, the ACL showed complete loss of tension, and was therefore reconstructed simultaneously to enable proper meniscal healing. DISCUSSION AND CONCLUSION: Chronic ACL insuffiency is a major risk factor for subsequent medial meniscus tear, especially bucket handle tear. The locked knee might unable proper pre-operative clinical examination. The preoperative MRI therefore being the only possibility to diagnose concomitant ligamentous injury. This is the first case reported in literature showing, that a positive PCL angle sign might be falsely negative due to a locked medial meniscus bucket handle tear.

Inflammation and Hypervascularization in a Large Animal Model of Knee Osteoarthritis: Imaging with Pathohistologic Correlation.

PURPOSE: To evaluate if synovial inflammation and hypervascularization are present in a dog model of knee osteoarthritis and can be detected on conventional magnetic resonance imaging (MRI), dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI), contrast-enhanced magnetic resonance imaging (CE-MRI), and quantitative digital subtraction angiography (Q-DSA) imaging. MATERIALS AND METHODS: Six dogs underwent MRI and angiography of both knees before and 12 weeks after right knee anterior cruciate ligament injury. Synovial vascularity was evaluated on CE-MRI, DCE-MRI, and Q-DSA by 2 independent observers. Synovial inflammation and vascularity were histologically scored independently. Cartilage lesions and osteophytes were analyzed macroscopically, and cartilage volumetry was analyzed by MRI. Vascularity and osteoarthritis markers on imaging were compared before and after osteoarthritis generation, and between the osteoarthritis model and the control knee, using linear mixed models accounting for within-dog correlation. RESULTS: In all knees, baseline imaging showed no abnormalities. Control knees did not develop significant osteoarthritis changes, synovial inflammation, or hypervascularization. In osteoarthritis knees, mean synovial enhancement score on CE-MR imaging increased by 13.1 ± 0.59 (P < .0001); mean synovial inflammation variable increased from 47.33 ± 18.61 to 407.97 ± 18.61 on DCE-MR imaging (P < .0001); and area under the curve on Q-DSA increased by 1058.58 ± 199.08 (P = .0043). Synovial inflammation, hypervascularization, and osteophyte formations were present in all osteoarthritis knees. Histology scores showed strong correlation with CE-MR imaging findings (Spearman correlation coefficient [SCC] = 0.742; P = .0002) and Q-DSA findings (SCC = 0.763; P < .0001) and weak correlation with DCE-MR imaging (SCC = -0.345; P = .329). Moderate correlation was found between CE-MR imaging and DSA findings (SCC = 0.536; P = .0004). CONCLUSIONS: In this early-stage knee osteoarthritis dog model, synovial inflammation and hypervascularization were found on imaging and confirmed by histology.

Midterm Clinical Outcomes and MR Imaging Changes after Transcatheter Arterial Embolization as a Treatment for Mild to Moderate Radiographic Knee Osteoarthritis Resistant to Conservative Treatment.

PURPOSE: To describe the safety and efficacy of transcatheter arterial embolization for mild to moderate radiographic knee osteoarthritis (OA) that is resistant to conservative treatment. MATERIALS AND METHODS: This prospective study included 72 patients (95 knees) with OA of Kellgren-Lawrence (KL) grade 1-3 and persisting moderate to severe pain that was resistant to conservative management who were treated with transcatheter arterial embolization between July 2012 and March 2016. Clinical outcomes were evaluated at 1, 4, and 6 months and then every 6 months for a maximum of 4 years. The Whole-Organ Magnetic Resonance Imaging Score (WORMS) was evaluated at baseline and at 2 years after embolization in 35 knees. RESULTS: Abnormal neovessels were identified in all cases. There were no major adverse events related to the procedures. Mean Western Ontario and McMaster Universities Osteoarthritis Index pain scores significantly decreased from baseline to 1, 4, 6, 12, and 24 months after treatment (12.1 vs 6.2, 4.4, 3.7, 3.0, and 2.6; all P < .001). The cumulative clinical success rates at 6 months and 3 years after embolization were 86.3% (95% confidence interval [CI], 78%-92%) and 79.8% (95% CI, 69%-87%), respectively. WORMS scores at 2 years after embolization in 35 knees showed significant improvement of synovitis vs baseline (P = .0016) and no osteonecrosis or other evidence indicating aggressive progression of degenerative changes. CONCLUSIONS: Transcatheter arterial embolization significantly improved pain symptoms and clinical function in patients with mild to moderate knee OA that was resistant to conservative treatment.

The value of protective head cap and glasses in neurointerventional radiology.

BACKGROUND: Protection of the head and eyes of the neurointerventional radiologist is a growing concern, especially after recent reports on the incidence of brain cancer among these personnel, and the revision of dose limits to the eye lens. The goal of this study was to determine typical occupational dose levels and to evaluate the efficiency of non-routine radiation protective gear (protective eyewear and cap). Experimental correlations between the dosimetric records of each measurement point and kerma area product (KAP), and between whole body doses and eye lens doses were investigated. METHODS: Measurements were taken using thermoluminescent dosimeters placed in plastic bags and worn by the staff at different places. To evaluate the effective dose, whole body dosimeters (over and under the lead apron) were used. RESULTS: The mean annual effective dose was estimated at 0.4 mSv. Annual eye lens exposure was estimated at 17 mSv when using a ceiling shield but without protective glasses. The protective glasses reduced the eye lens dose by a factor of 2.73. The mean annual dose to the brain was 12 mSv; no major reduction was observed when using the cap. The higher correlation coefficients with KAP were found for the dosimeters positioned between the eyes (R(2)=0.84) and above the apron, and between the eye lens (R(2)=0.85) and the whole body. CONCLUSIONS: Under the specific conditions of this study, the limits currently applicable were respected. If a new eye lens dose limit is introduced, our results indicate it could be difficult to comply with, without introducing additional protective eyewear.

Radiologic patterns of necrosis after proton therapy of skull base tumors.

BACKGROUND: Discrimination between radiation necrosis and tumor progression after radiation therapy represents a radiologic challenge. The aim of our investigation is to identify patterns of radiation necrosis on brain magnetic resonance imaging (MRI) and positron emission tomography (PET) with Fluoroethyltyrosin (FET) after proton beam therapy (PBT) for skull base tumors. MATERIAL AND METHODS: Five consecutive patients with extra-axial neoplasms were included, presenting a total of eight radiation necrosis lesions (three clival chordomas; two petroclival chondrosarcomas; two women; mean age: 49 ± 18.2 years). Radiation necrosis was defined as the appearance of abnormal enhancement on MRI after PBT decreasing over time, and additional histopathologic confirmation in one patient. MRI and PET imaging were retrospectively analyzed by two experienced radiologists in consensus. RESULTS: All lesions were localized close to the primary tumor in the field of irradiation. Three patients showed bilateral symmetrical lesions. All lesions showed T2 hyperintensity and T1 hypointensity. Cerebral blood volume (CBV) was reduced in all available studies. None of the lesions showed a restricted diffusion. FET-PET (three patients) showed a higher uptake in four out of five lesions; three of which had a mean tumor-to-background (TBRmean) uptake lower than 1.95 and FET uptake increasing over time and were correctly classified into radiation necrosis. CONCLUSIONS: Most radiation necroses were in direct continuity with the primary tumor mimicking tumor progression. The most consistent imaging findings for PBT radiation necrosis are low CBV without restricted diffusion and FET-PET TBRmean lower than 1.95 or increasing uptake over time. Bilateral symmetric involvement may be another indicator of radiation necrosis.Critères radiologiques de la nécrose après protonthérapie des tumeurs de la base du crâne.

Pseudoprogression after proton beam irradiation for a choroid plexus carcinoma in pediatric patient: MRI and PET imaging patterns.

PURPOSE: Pseudoprogression is a rare complication of radiation therapy, and discrimination between true progression and pseudoprogression is of paramount importance for further medical care. We present a case of intra-axial pseudoprogression following complementary proton radiation therapy for a choroid plexus carcinoma in a child. We aim to highlight radiological patterns of pseudoprogression after proton beam therapy. CASE REPORT: A 6-year-old girl presented with choroid plexus carcinoma, manifesting as change in behavior, tremor, and balance disorder. Partial resection and chemotherapy were performed. Complementary localized proton beam therapy (54 Gy) was administered on the residual tumor. Eight month follow-up MRI showed an abnormal, irregular, rim-like enhancement in the pons and both temporal lobes within the field of irradiation. These lesions had a low cerebral blood volume (CBV) on perfusion MR imaging and no restricted diffusion. However, the lesions were hypermetabolic on O-(2-[18F]fluoroethyl)-L-tyrosine (FET)-PET MRI. Follow-up MRI showed disappearance of these lesions confirming the perfusion MR diagnosis of pseudoprogression. CONCLUSION: Based on this case, radiological patterns of pseudoprogression after proton beam therapy may be a low CBV and no restricted diffusion. Lesions can be hypermetabolic on FET-PET imaging.