Broström ankle ligament repair augmented with suture tape : Results of magnetic resonance imaging evaluation.

BACKGROUND: The Broström procedure is an established procedure in cases of primary lateral ankle ligament repair (LALR). To improve postoperative stability an augmentation device, InternalBrace™ (Arthrex, Naples, FL) has been introduced. This study evaluates remodelling of the anterior talofibular ligament (ATFL) in patients undergoing a tape augmented Broström technique as well as clinical outcomes. METHODS: In this study 32 patients with chronic lateral ankle instability (CLAI) receiving augmented LALR were included. Clinical outcomes were evaluated at a one-time postoperative visit between 12 and 18 months. A 3 T magnetic resonance imaging (MRI) was done to evaluate the morphology of the ATFL. Statistical analysis was completed with the free software and environment R version 3.6.3 (Bell Laboratories, Murray Hill, NJ, USA) and P-values < 0.05 were considered statistically significant. RESULTS: The mean follow-up time was 15.3 ± 1.8 months with a return to sport time of 4.0 ± 2.4 months. The average AOFAS (American Orthopaedic Foot and Ankle Society Score) score was 94.4 ± 7.2, the FAOS (Foot and Ankle Outcome Score) demonstrated 87.3 ± 10.4 points and the FFI (Foot Function Index - 2 scores (pain and function score)) was 22.9 ± 20.1 and 15.4 ± 10.4, respectively. The MRI findings demonstrated an average length of the ATFL of 18.6 ± 4.3 mm and the width was 3.6 ± 0.9 mm. A clear differentiation between the ATFL and the augmentation device could be shown in 28 cases. The Fisher's exact test could not depict a significant correlation between the presence of a bone marrow edema and the tension of the augmentation device with a level of significance of α = 0.05. CONCLUSION: An anatomical healing tendency of the ligament repair and good integrity of the augmentation device could be shown based on MRI findings. The lateral ligament repair augmented with suture tape is an effective and safe procedure regarding surgical treatment in chronic lateral ankle instability producing good clinical outcome.

A framework based on subject-specific musculoskeletal models and Monte Carlo simulations to personalize muscle coordination retraining.

Excessive loads at lower limb joints can lead to pain and degenerative diseases. Altering joint loads with muscle coordination retraining might help to treat or prevent clinical symptoms in a non-invasive way. Knowing how much muscle coordination retraining can reduce joint loads and which muscles have the biggest impact on joint loads is crucial for personalized gait retraining. We introduced a simulation framework to quantify the potential of muscle coordination retraining to reduce joint loads for an individuum. Furthermore, the proposed framework enables to pinpoint muscles, which alterations have the highest likelihood to reduce joint loads. Simulations were performed based on three-dimensional motion capture data of five healthy adolescents (femoral torsion 10°-29°, tibial torsion 19°-38°) and five patients with idiopathic torsional deformities at the femur and/or tibia (femoral torsion 18°-52°, tibial torsion 3°-50°). For each participant, a musculoskeletal model was modified to match the femoral and tibial geometry obtained from magnetic resonance images. Each participant's model and the corresponding motion capture data were used as input for a Monte Carlo analysis to investigate how different muscle coordination strategies influence joint loads. OpenSim was used to run 10,000 simulations for each participant. Root-mean-square of muscle forces and peak joint contact forces were compared between simulations. Depending on the participant, altering muscle coordination led to a maximum reduction in hip, knee, patellofemoral and ankle joint loads between 5 and 18%, 4% and 45%, 16% and 36%, and 2% and 6%, respectively. In some but not all participants reducing joint loads at one joint increased joint loads at other joints. The required alteration in muscle forces to achieve a reduction in joint loads showed a large variability between participants. The potential of muscle coordination retraining to reduce joint loads depends on the person's musculoskeletal geometry and gait pattern and therefore showed a large variability between participants, which highlights the usefulness and importance of the proposed framework to personalize gait retraining.

Influence of Scan Parameters of Single and Dual-Energy CT Protocols in Combination with Metal Artifact Suppression Algorithms for THA: An ex Vivo Study.

BACKGROUND: Metal artifacts caused by hip arthroplasty stems limit the diagnostic value of computed tomography (CT) in the evaluation of periprosthetic fractures or implant loosening. The aim of this ex vivo study was to evaluate the influence of different scan parameters and metal artifact algorithms on image quality in the presence of hip stems. METHODS: Nine femoral stems, 6 uncemented and 3 cemented, that had been implanted in subjects during their lifetimes were exarticulated and investigated after death and anatomical body donation. Twelve CT protocols consisting of single-energy (SE) and single-source consecutive dual-energy (DE) scans with and without an iterative metal artifact reduction algorithm (iMAR; Siemens Healthineers) and/or monoenergetic reconstructions were compared. Streak and blooming artifacts as well as subjective image quality were evaluated for each protocol. RESULTS: Metal artifact reduction with iMAR significantly reduced the streak artifacts in all investigated protocols (p = 0.001 to 0.01). The best subjective image quality was observed for the SE protocol with a tin filter and iMAR. The least streak artifacts were observed for monoenergetic reconstructions of 110, 160, and 190 keV with iMAR (standard deviation of the Hounsfield units: 151.1, 143.7, 144.4) as well as the SE protocol with a tin filter and iMAR (163.5). The smallest virtual growth was seen for the SE with a tin filter and without iMAR (4.40 mm) and the monoenergetic reconstruction of 190 keV without iMAR (4.67 mm). CONCLUSIONS: This study strongly suggests that metal artifact reduction algorithms (e.g., iMAR) should be used in clinical practice for imaging of the bone-implant interface of prostheses with either an uncemented or cemented femoral stem. Among the iMAR protocols, the SE protocol with 140 kV and a tin filter produced the best subjective image quality. Furthermore, this protocol and DE monoenergetic reconstructions of 160 and 190 keV with iMAR achieved the lowest levels of streak and blooming artifacts. LEVEL OF EVIDENCE: Diagnostic Level III . See Instructions for Authors for a complete description of levels of evidence.

Health care reform in the USA: Recommendations from USA and non-USA radiologists.

AIM: To compare the opinions and recommendations of imaging specialists from United States (USA) and non-USA developed nations for USA health care reform. METHODS: A survey was emailed out to 18 imaging specialists from 17 non-USA developed nation countries and 14 radiologists within the USA regarding health care reform. The questionnaire contained the following questions: what are the strengths of your health care system, what problems are present in your nation's health care system, and what recommendations do you have for health care reform in the USA. USA and non-USA radiologists received the same questionnaire. RESULTS: Strengths of the USA health care system include high quality care, autonomy, and access to timely care. Twelve of 14 (86%) USA radiologists identified medicolegal action as a major problem in their health care system and felt that medicolegal reform was a critical aspect of health care reform. None of the non-USA radiologists identified medicolegal aspects as a problem in their own country nor identified it as a subject for USA health care reform. Eleven of 14 (79%) USA radiologists and 16/18 (89%) non-USA radiologists identified universal health care coverage as an important recommendation for reform. CONCLUSION: Without full universal coverage, meaningful health care reform will likely require medicolegal reform as an early and important aspect of improved and efficient health care.

Treatment of Hemodialysis-Associated Adynamic Bone Disease with Teriparatide (PTH1-34): A Pilot Study.

BACKGROUND: Adynamic bone disease (ABD) is caused by a relative or absolute parathyroid hormone (PTH) deficiency. Teriparatide (PTH1-34) is an osteoanabolic agent in clinical use. Here, it was hypothesized that treatment with teriparatide improves bone mineral density (BMD) of ABD patients. PATIENTS AND METHODS: Seven hemodialysis patients with ABD and a median iPTH level of 22 pg/ml were evaluated in this open-label, prospective, 6-month observational pilot-study. All patients received 20 µg teriparatide/day subcutaneously. Serologic bone markers, BMD and coronary artery calcification (CAC) were measured at baseline and after 6 months. RESULTS: Teriparatide therapy led to a significant increase in lumbar spine (0.885 ± 0.08 vs. 0.914 ± 0.09 g/cm(2), p < 0.02), but not femoral neck (0.666 ± 0.170 vs. 0.710 ± 0.189 g/cm(2), p = 0.18) BMD. Compared to pretreatment values, calculated monthly changes in BMD improved significantly in both the lumbar spine and femoral neck (p < 0.02). Changes in serologic markers of bone turnover and CAC scores were not statistically significant. CONCLUSION: Teriparatide therapy might improve low BMD in hemodialysis patients with ABD. Further clinical studies are needed to establish teriparatide as a therapeutic option for dialysis patients with ABD.

In vitro imaging of coronary artery stents: are there differences between 16- and 64-slice CT scanners?

PURPOSE: To compare the performance of 64-slice with 16-slice CT scanners for the in vitro evaluation of coronary artery stents. METHODS AND MATERIALS: Twelve different coronary artery stents were placed in the drillings of a combined heart and chest phantom, which was scanned with a 16- and 64-slice CT scanner. Coronal reformations were evaluated for artificial lumen narrowing, intraluminal attenuation values, and false widening of the outer stent diameter as an indicator of artifacts outside the stent. RESULTS: Mean artificial lumen narrowing was not significantly different between the 16- and 64-slice CT scanner (44% versus 39%; p=0.408). The differences between the Hounsfield Units (HU) measurements inside and outside the stents were significantly lower (p=0.001) with 64- compared to 16-slice CT. The standard deviation of the HU measurements inside the stents was significantly (p=0.002) lower with 64- than with 16-slice CT. Artifacts outside the stents were not significantly different between the scanners (p=0.866). CONCLUSION: Visualization of the in-stent lumen is improved with 64-slice CT when compared with 16-slice CT as quantified by significantly lesser intraluminal image noise and less artificial rise in intraluminal HU measurement, which is the most important parameter for the evaluation of stent patency in vivo.

Atrial function after ablation procedure in patients with chronic atrial fibrillation using steady-state free precession magnetic resonance imaging.

BACKGROUND: Surgical ablation procedures are an established surgical procedure for restoration of sinus rhythm and reestablishment of atrial function in patients with chronic atrial fibrillation. The purpose of this study was to evaluate the feasibility and reproducibility of steady-state free precession magnetic resonance imaging (SSFP MRI) for examination of atrial dimensions and function after ablation procedures. METHODS: Nineteen patients (mean age, 63.1 +/- 11.7 years) being at least six months after surgical ablation procedure, with stable sinus rhythm, were selected for the study. They underwent cardiac MRI. End-diastolic and end-systolic volumes were measured using Simpson's rule. The presence of visual contraction was visually assessed. RESULTS: In MRI evaluation mean end-diastolic volume of the right atrium and left atrium after an ablation procedure was 127 +/- 45 mL and 163 +/- 50 mL, respectively. Mean stroke volume was 23 +/- 15 mL and 26 +/- 12 mL for the right and left atrium. Mean ejection fraction of the right atrium was 0.19 +/- 0.14 and 0.17 +/- 0.1 for the left atrium. An atrial kick of both atria was observed in 8 of 19 (47%) patients. An atrial kick of only the right atrium was observed in an additional 13 of 19 (68%) patients. CONCLUSIONS: The anticipated events after a surgical ablation procedure are the restoration of atrial contractility and the associated atrial kick, thereby enhancing cardiac output and decreasing the risk of thromboembolism. Evaluation of atrial function after an ablation procedure using SSFP MRI is feasible and allows a standardized documentation of postoperative atrial function, thus allowing evaluation of the surgical outcome in a reproducible way. Echocardiographic evaluation seems to underestimate the transport function of the atrium.

Incidence of chronic knee lesions in long-distance runners based on training level: findings at MRI.

PURPOSE: The purpose of this study was to evaluate the incidence of chronic knee changes in long-distance runners based on the training status, including distance, running frequency, training pace, and running experience. METHODS: MRI of the knee was performed in 26 non-professional runners 5 days after their last training unit. Lesions of the menisci and cartilage (5-point scale), bone marrow and ligaments (3-point scale), and joint effusion were evaluated. A total score comprising all knee lesions in each runner was evaluated. The incidence of the knee changes was correlated with the training level, gender, and age of the runners. RESULTS: Grade 1 lesions of the menisci were found in six runners with a high training level, and in only four runners with a low training level. Grade 1 cartilage lesions were found in three high-trained runners and in one low-trained runner, and grade 2 lesions were found in one high-trained runner and in two low-trained runners, respectively. Grade 1 anterior cruciate ligament lesions were seen in three runners with a high- and in two runners with a low-training level. Runners with a higher training level showed a statistically significant higher score for all chronic knee lesions than those with a lower training level (p<0.05). CONCLUSIONS: MRI findings indicate that a higher training level in long-distance runners is a risk factor for chronic knee lesions.

Total endoscopic CABG using robotics on beating heart.

BACKGROUND: The implementation of a total endoscopic coronary surgery on the beating heart with the aid of the Da Vinci surgical system (Intuitive, Sunnyvale, CA) requires a stepwise learning process. After cadaveric training and clinical start of the program in November 2002, we gained experience with arrested heart procedures starting in May 2003. In November 2003, we moved to beating heart surgery. METHODS: From November 2003 to January 2005, 14 patients with coronary artery disease (mean age of 62 +/- 5 years, female to male ratio 2:12) were operated with the intention to perform a beating heart TECAB (totally endoscopic coronary artery bypass grafting) procedure. RESULTS: Total conversion rate was 35% (5/14), due to pleural adhesions in 2 patients, injury of the lung during port placement, inability to occlude the LAD with saddle loops, atherosclerotic diseased mammary artery in 1 patient each. Mean operating time was 298 +/- 110 minutes with a steady decline throughout the study period (first 5 patients: 342 +/- 61 minutes, patients 6 to 9: 337 +/- 87 minutes, last 4 patients: 290 +/- 53 minutes), resulting in a 60 minute shorter operating time. Mean ICU stay was 1.3 days and hospital stay lasted on average 8.4 +/- 2.8 days. CONCLUSION: Total endoscopic bypass surgery on the beating heart with the Da Vinci surgical system can be safely implemented in clinical use. The learning curve results in a constantly decreasing procedure time due to a more effective table team-console surgeon-robotic system interaction and a moderate conversion rate.

Effects of TIPS on liver perfusion measured by dynamic CT.

OBJECTIVE: Our aim was to measure the arterial, portal venous, and total perfusion of the liver parenchyma with dynamic, single-section CT in patients with liver cirrhosis before and after transjugular intrahepatic portosystemic shunt (TIPS) placement and to compare the results with normal values. SUBJECTS AND METHODS: Perfusion of the liver parenchyma was measured in 24 healthy volunteers and 41 patients with liver cirrhosis using dynamic single-section CT. Seventeen patients underwent TIPS placement, and CT measurements were repeated within 7 days. CT scans were obtained at a single level comprising the liver, spleen, aorta, and portal vein. Scans were obtained over a period of 88 sec (one baseline scan followed by 16 scans every 2 sec and eight scans every 7 sec) beginning with the injection of a contrast agent bolus (40 mL at 10 mL/sec). Parenchymal and vascular contrast enhancement was measured with regions of interest, and time-density curves were obtained. These data were processed with a pharmaco-dynamic fitting program (TopFit), and the arterial and portal venous component and the total perfusion of the hepatic parenchyma were calculated (milliliters of perfusion per minute per 100 mL of tissue). RESULTS: Mean normal values for hepatic arterial, portal venous, and total perfusion were 20, 102, and 122 mL/min per 100 mL, respectively. In patients with cirrhosis before TIPS, mean hepatic arterial, portal venous, and total perfusion was 28, 63, and 91 mL/min per 100 mL, respectively, which was statistically significant for all values (p <0.05). After TIPS, hepatic perfusion increased to a mean value of 48, 65, 113 mL/min per 100 mL for arterial (p <0.01), portal venous, and total (p=0.011) perfusion, respectively. CONCLUSION: In patients with cirrhosis, the hepatic arterial perfusion increased, whereas portal venous and total perfusion decreased compared with that of healthy volunteers. TIPS placement caused a statistically significant increase of the hepatic arterial and total hepatic perfusion. The portal venous parenchymal perfusion remained unchanged.

MR cholangiopancreatography.

Although MRCP is still an evolving technique, it has established itself as clinically useful and comparable with ERCP for the evaluation of various biliary or pancreatic ductal diseases. MRCP is not only comparable with ERCP in its diagnostic ability, but it has the tremendous advantage of being noninvasive. Furthermore, MR imaging is useful in patients with incomplete or failed ERCP, and in patients with certain biliary or gastrointestinal surgical procedures it is the imaging modality of choice. ERCP will remain an extremely important modality because of the great clinical importance for interventional biliary procedures with this technique. Nonetheless, MRCP may in the near future replace most of the diagnostic imaging of the biliary tree, with diagnostic results even more improved with further developments of hardware and technique.

MR imaging features of primary sclerosing cholangitis: patterns of cirrhosis in relationship to clinical severity of disease.

PURPOSE: To evaluate the spectrum of magnetic resonance (MR) imaging appearances of the liver in primary sclerosing cholangitis (PSC) and to examine their correlation with clinical stage of disease. MATERIALS AND METHODS: Fifty-two patients (25 female, 27 male; mean age, 43 years; age range, 11-87 years) with PSC underwent nonenhanced and gadolinium-enhanced MR imaging. Two abdominal radiologists retrospectively reviewed all images (independently and then in consensus) for the imaging pattern of the liver parenchyma, presence and grade of intrahepatic biliary ductal dilatation, and presence of areas of parenchymal atrophy or abnormal signal intensity and/or gadolinium enhancement. Imaging findings were correlated with Child class, Child-Turcotte-Pugh score, and Mayo end-stage liver disease (MELD) score. Statistical analyses (kappa scoring for interobserver agreement, McNemar test, Mann-Whitney U test, multiple regression analysis, Spearman correlation) were performed. RESULTS: Of 52 patients, seven (13%) had no imaging findings of cirrhosis, 17 (33%) had a diffuse pattern of cirrhosis, and 28 (54%) had a large macronodular pattern (with nodules >or=3 cm) (kappa = 0.84). Intrahepatic biliary ductal dilatation was observed in 44 (85%) patients and was general in 18 (35%) and segmental in 26 (50%). Peripheral wedge-shaped areas of parenchyma were observed with atrophy in 23 (44%) and 25 (48%) patients by the two readers (kappa = 0.76) and without atrophy in 18 (35%) patients by both readers (kappa = 1.00). No correlation was found between imaging findings and clinical scores (P >.05, multiple regression analysis; P =.25-.75, Mann-Whitney U test; Spearman correlation coefficients between -0.33 and 0.33). CONCLUSION: The spectrum of MR imaging appearances of PSC is diverse and comprises distinct patterns that do not appear to correlate with severity of disease. Large regenerative nodules are a frequent finding and may help to establish the diagnosis.

Magnetic resonance imaging of pulmonary parenchymal disease using a modified breath-hold 3D gradient-echo technique: initial observations.

PURPOSE: To determine the potential of a modified breath-hold 3D gradient-echo technique for visualizing pulmonary parenchymal diseases. MATERIALS AND METHODS: Twenty-one magnetic resonance imaging (MRI) studies of the lungs were performed in 20 patients (15 male and 5 female; age range, 7.7-86.1 years) with pulmonary diseases comprising non-small-cell, small-cell, and bronchioalveolar carcinomas, endobronchial mucoepidermoid carcinoma, metastases, pneumonia, Wegener's granulomatosis, chronic obstructive pulmonary disease, arterio-venous malformation, and bronchogenic cyst. Confirmation of diagnoses was obtained via histopathology (14 patients) and follow-up (6 patients). MRI studies were performed at 1.5 T before and after administration of gadolinium using a modified volumetric interpolated breath-hold examination (VIBE) sequence. All images were evaluated prospectively regarding lesion detection and characterization. MR findings were correlated with final diagnoses. Retrospective grading (scores, 1-4) was performed for general image quality (rated "poor" to "excellent"); presence of artifacts ("negligible" to "severe"); and imaging quality of pulmonary lesions (conspicuity and contrast on pre- and postgadolinium images). RESULTS: Twenty-three solid pulmonary lesions, 25 infiltrates and segmental atelectases, and 1 cyst were detected and prospectively correctly diagnosed. Sizes ranged from 0.3-10 cm. The mean scores for image quality and presence of artifacts were 3.3 (SD, 0.7) and 1.8 (SD, 0.7), respectively. Conspicuity and contrast of pulmonary lesions received mean scores between 3.0 and 3.8 (SD, 0.4-0.7). CONCLUSION: This MRI technique allows imaging of a wide spectrum of solid and nonsolid pulmonary parenchymal diseases with reproducible high image quality, effective suppression of artifacts, high resolution, and visualization of gadolinium enhancement.