Extrusion and meniscal mobility evaluation in case of ramp lesion injury: a biomechanical feasibility study by 7T magnetic resonance imaging and digital volume correlation.

Introduction: The existing body of literature on the biomechanical implications of ramp lesions is limited, leaving a significant gap in our understanding of how these lesions impact joint kinematics and loading in the medial compartment. This cadaveric biomechanical study aims to address this gap by employing an innovative Digital Volume Correlation (DVC) method, utilizing 7 Tesla Magnetic Resonance Imaging (MRI) images under various loading conditions. The primary objective is to conduct a comprehensive comparison of medial meniscal mobility between native knees and knees affected by grade 4 ramp lesions. By focusing on the intricate dynamics of meniscal mobility and extrusion, this work seeks to contribute valuable insights into the biomechanical consequences of medial meniscus ramp lesions. Materials and methods: An initial set of 7T MRI imaging sessions was conducted on two intact native knees, applying load values up to 1500N. Subsequently, a second series of images was captured on these identical knees, with the same loads applied, following the creation through arthroscopy of medial meniscus ramp lesions. The application of DVC enabled the precise determination of the three components of displacement and spatial variations in the medial menisci, both with and without ramp lesions. Results: The measured directional displacements between native knees and injured knees indicate that, following the application of axial compression load, menisci exhibit increased extrusion and posterior mobility as observed through DVC. Discussion: Injuries associated with Subtype 4 medial meniscus ramp lesions appear to elevate meniscal extrusion and posterior mobility during axial compression in the anterior cruciate ligament of intact knees. Following these preliminary results, we plan to expand our experimental approach to encompass individuals undergoing weight-bearing MRI. This expansion aims to identify meniscocapsular and/or meniscotibial insufficiency or rupture in patients, enabling us to proactively reduce the risk of osteoarthritic progression.

Avascular osteonecrosis of the hip: The vision of the radiologist (radiology, MRI, CT and scintigraphy).

Hip osteonecrosis is a localization at the hip of aseptic osteonecrosis, a disease characterized by bone infarction. Face to a painful hip, the first examination to carry out should be a standard radiograph examination. At an early stage, the radiographs remain strictly normal MRI remains the reference examination with a sensitivity of 71-100% and specificity of 94-100%. On T2 weighting-imaging, a hyperintense line between the normal and ischemic marrow is sometimes visible; this sign is pathognomonic of bone necrosis and is known as the "double line sign". This article reviews imaging features of standard radiographs, computed tomography and MRI and addresses the role of imaging in this pathology.

Glioma-grade diagnosis using in-phase and out-of-phase T1-weighted magnetic resonance imaging: A prospective study.

PURPOSE: The purpose of this prospective study was to determine whether chemical shift gradient-echo magnetic resonance imaging (MRI) could predict glioma grade. MATERIALS AND METHODS: A total of 69 patients with 69 gliomas were prospectively included. There were 41 men and 28 women with a mean age of 50±(SD) years (range: 16-82years). All patients had MRI of the brain including chemical shift gradient-echo sequence, further referred to as in- and out-of phase sequence (IP/OP). Intravoxel fat content was estimated by signal loss ratio (SLR=[IP-OP]/2IP), between in- and out-of-phase images, using a region of interest placed on the viable portion of the gliomas. Association between SLR and glioma grade was searched for using Wilcoxon and Mann-Whitney U tests and diagnostic capabilities using area under the receiver operating characteristic (AUROC) curves. RESULTS: A significant association was found between SLR value and glioma grade (P<0.0001). SLR>9‰ allowed complete discrimination between grade III and grade II glioma with 100% specificity (95% CI: 85-100%), 100% sensitivity (95% CI: 78-100%) and 100% accuracy (95% CI: 90-100%) (AUROC=1). A SLR>20‰ allowed discriminating between grade IV and grade III glioma with 75% specificity (95% CI: 57-89%), 73% sensitivity (95% CI: 45-92%) and 72% accuracy (95% CI: 57-84%) (AUC=0.825, 95% CI: 0.702-0.948). The AUROC for the diagnosis of high-grade glioma (grade III and IV vs. grade II) was 1. CONCLUSION: Chemical shift gradient echo MRI provides accurate grading of gliomas. This simple method should be used as a biomarker to predict glioma grade.

Intra peritoneal abdominal fat area measured from computed tomography is an independent factor of severe acute pancreatitis.

PURPOSE: The purpose of this study was to search for a possible relationship between acute pancreatitis (AP) severity and visceral fat (VF) surface on contrast-enhanced computed tomography (CECT). MATERIAL AND METHOD: A total of 112 patients with AP who underwent CECT within 2 to 3 days after the beginning of AP were included. There were 68 mean and 44 women, with a mean age of 56.3±21.6 (SD) years (range: 19-98 years). AP was regarded as mild for patients with an hospital stay up to 5 days and severe for those with an hospital stay greater than 5 days. VF surface was measured on CECT at the level of L4-L5 and of the umbilicus. Association between AP severity and VF surface, computed tomography severity index (CTSI), modified CTSI (mCTSI) and other variables were searched for using uni- and multivariate analysis. RESULTS: At univariate analysis, the VF surface at the level of L4 was greater in patients with severe AP (129.3±68.6 [SD] cm2; range: 21.8-355.8 cm2) than in patients with mild AP (100.1±68.4 [SD] cm2; range:13.2-333 cm2) (P=0.006). Similarly, the VF surface at the umbilicus was greater in patients with severe AP (161.1±76.1 [SD] cm2; range: 31.3-376.7cm2) than in those with mild AP (128.4±74.3cm2; range: 12.8-323.1cm2) (P=0.024). CTSI and mCTSI were also associated to AP severity. At multivariate analysis, only VF surface either measured at the umbilical or at the L4-L5 level was associated with AP severity (P=0.017 and 0.006, respectively). CONCLUSION: VF surface at the level of L4-L5 on CECT is an independent factor of AP severity. VF surface at the level of L4-L5 on CECT is an independent factor of AP severity. These results are in line with recent data on the role of abdominal fat in the genesis of inflammatory response, which is associated with severe forms of AP.

Chart for renal tumor microwave ablation from human study.

PURPOSE: To define microwave ablation (MWA) charts according to time and power in human renal tumors and to compare them to the charts given by the HS AMICA manufacturer. MATERIALS AND METHODS: A total of 54 patients with 54 renal cancers who underwent MWA were included. There were 36 men and 18 women with a mean age of 72.5±10[SD] years (range: 40-91years). The system used for MWA was HS AMICA with the Amica-probe V4 applicator. The following variables (antero-posterior diameter, transverse diameter, cranio-caudal diameter and volume were measured on computed tomography examinations performed one month after MWA. The dimensions of the ablation zone were correlated with power (40 or 60W) and exposure time (5, 10 and 15min) used for MWA. Actual ablation dimensions were compared to the manufacturer's data. RESULTS: The variation of diameters, with a longer ablation time, was linear at 40W with a volume increase of 30% for each additional 5minutes. At 60W, a more pronounced variation (volume increase of 112%) was observed. Compared to the manufacturer's chart, significantly larger ablation zones were obtained (P<0.05), the differences being mainly marked for the antero-posterior diameter (≥1cm). CONCLUSION: MWA using AMICA generator produces reproducible ablation area for given time and power in renal tumor ablation. The charts presented here should be used instead of the manufacturer's chart, which is based on porcine liver and is significantly different.

Left atrial volume assessed by ECG-gated computed tomography: Variations according to age, gender and time during the cardiac cycle.

PURPOSE: The purpose of this study was to retrospectively assess the accuracy of the maximal left atrial volume (LAVmax) measured at 75% of the cardiac cycle compared to the 40% measurements and to evaluate this volume according to age and gender. PATIENTS AND METHOD: A total of 150 patients with a mean age of 50±17 (SD) years (range: 21-79 years) were analyzed. There were 78 men and 72 women. LAVmax were measured from retrospective triphasic cardiac-gated multi-detector computed tomography (MDCT) data at the 40% (LAV40) and 75% (LAV75) of the RR cycle phases by a semi-automatic method. RESULTS: LAV40was 50.7±14mL/m2 and LAV75 was 42.5±13mL/m2. The difference was statistically significant. Considering the reference range of LAVmax reported in the literature, 33% of the patients had enlarged LA with LAV40 and only 17% with LAV75. These volumes were positively influenced by age but not by gender. The relationship between LAV75 and LAV40 was: LAV75=0.908 LAV40-3.486 (r2=0.92) or LAV40=1.1×LAV75+3.8 (r2=0.92). CONCLUSION: LAVmax measured at the 75% of the cardiac cycle phase significantly underestimates actual LAV leading to reconsider normal values. LAV40 can be computed from the measured value of LAV75 obtained on prospective ECG-gated MDCT.

Percutaneous microwave ablation of renal cancers under CT guidance: safety and efficacy with a 2-year follow-up.

AIM: To evaluate the safety and efficiency of percutaneous microwave ablation (MWA) of renal cell carcinomas (RCC) carried out under computed tomography (CT) guidance. MATERIALS AND METHODS: A retrospective study was performed on RCC that was either histologically proven or diagnosed at imaging (Bosniak IV cyst) and treated by MWA under general anaesthesia with CT guidance. Indications for percutaneous ablation were based on the American Urological Association recommendations. Twenty-four months post-procedure follow-up was performed. RESULTS: Sixty-two patients presenting one or more RCC (84 tumours ranging from 10-48 mm in diameter; mean diameter: 25.6 mm) were included. Technical success was achieved for 78 tumours (58 patients). For four patients, the treatment was stopped due to gas dissection failure. At 3 months, six residual tumours were observed (8%). At 6 months, two recurrences and one residual tumour (3.8%) were observed; all were retreated with complete success. At 12 months, local control of the disease was achieved in 94% of cases (100% in cases where treatment was performed). Two cases of distal metastasis were observed after 12 and 24 months. At 24 months, one patient presented with a contralateral tumour. The complication rate was 4.8% including one grade III complication and two grade II complications according to the Clavien-Dindo classification. At 2 years, the cumulative disease-free survival rate and overall survival were 95% and 97%, respectively. CONCLUSION: MWA ablation under CT guidance to treat RCC is safe and provides a high rate of effectiveness at 24 months.

Irreversible electroporation for locally advanced pancreatic cancer.

Pancreatic adenocarcinoma is one of the solid cancers associated with the poorest prognosis; the only curative treatment remains surgical resection but in most cases, this treatment is not possible because of distant metastasis or local extension. Irreversible electroporation is a new tumor ablation technique, which provides cellular apoptosis without any thermal coagulation effect. This technique helps preserve the ducts, vessels or nerves located in the treatment area. This article reviews the current knowledge regarding the use of electroporation for the treatment of pancreatic adenocarcinoma.

Preoperative detection of hepatic metastases from colorectal cancer: Prospective comparison of contrast-enhanced ultrasound and multidetector-row computed tomography (MDCT).

PURPOSE: The goal of this study was to prospectively compare the sensitivity of contrast-enhanced ultrasound (CEUS) with that of multiphase multidetector-row computed tomography (MDCT) in the preoperative detection of hepatic metastases. MATERIALS AND METHOD: Forty-eight patients, with a mean age of 62years old (range: 43-85years) were prospectively included. All patients underwent CEUS following intravenous administration of 2.4mL of an ultrasound contrast agent (Sonovue(®), Bracco, Milan, Italy) and multiphase MDCT. Intraoperative ultrasound examination (IOUS) was used as the standard of reference. RESULTS: A total of 158 liver metastases were identified by IOUS, 127 by preoperative MDCT (sensitivity; 80.4%) and 102 by CEUS (sensitivity, 64.5%). The 15.9% difference in sensitivity between CEUS and MDCT was statistically significant (P=0.002). There was a disagreement between IOUS and CEUS in 23 patients (47%) and in 13 patients (27%) between IOUS and MDCT. MDCT identified one or more additional metastases in 10 patients (20%) resulting in a change in the surgical strategy. CONCLUSION: Based on an unselected patient cohort and using multiphase MDCT, CEUS is significantly inferior to MDCT for the preoperative detection of hepatic metastases of colorectal cancer.

Postoperative abdominal bleeding.

Postoperative bleeding following abdominal surgery is relatively rare and mainly depends on the type of surgery. Although bleeding is usually controlled by simple local treatment of symptoms, specific treatment including surgery or interventional radiology is sometimes necessary. This article reviews the clinical features that must be recognized depending on the type of surgery and especially focuses on the role of the radiologist in the management of this complication.

Low-grade gliomas: the challenges of imaging.

WHO grade II gliomas are a major challenge for magnetic resonance imaging (MRI) due to their delayed anaplastic transformation. Today it is possible to individually characterize tumor progression from diagnosis to anaplastic transformation based on the many parameters identified in studies in the literature and the possibility of integrating these data into mathematical models. Early identification of negative morphological and metabolic factors, as well as treatment follow-up, help identify predictive factors of tumor progression, as well as determine treatment response to adapt management of this disease.