Automated assessment of cardiac pathologies on cardiac MRI using T1-mapping and late gadolinium phase sensitive inversion recovery sequences with deep learning.

BACKGROUND: A deep learning (DL) model that automatically detects cardiac pathologies on cardiac MRI may help streamline the diagnostic workflow. To develop a DL model to detect cardiac pathologies on cardiac MRI T1-mapping and late gadolinium phase sensitive inversion recovery (PSIR) sequences were used. METHODS: Subjects in this study were either diagnosed with cardiac pathology (n = 137) including acute and chronic myocardial infarction, myocarditis, dilated cardiomyopathy, and hypertrophic cardiomyopathy or classified as normal (n = 63). Cardiac MR imaging included T1-mapping and PSIR sequences. Subjects were split 65/15/20% for training, validation, and hold-out testing. The DL models were based on an ImageNet pretrained DenseNet-161 and implemented using PyTorch and fastai. Data augmentation with random rotation and mixup was applied. Categorical cross entropy was used as the loss function with a cyclic learning rate (1e-3). DL models for both sequences were developed separately using similar training parameters. The final model was chosen based on its performance on the validation set. Gradient-weighted class activation maps (Grad-CAMs) visualized the decision-making process of the DL model. RESULTS: The DL model achieved a sensitivity, specificity, and accuracy of 100%, 38%, and 88% on PSIR images and 78%, 54%, and 70% on T1-mapping images. Grad-CAMs demonstrated that the DL model focused its attention on myocardium and cardiac pathology when evaluating MR images. CONCLUSIONS: The developed DL models were able to reliably detect cardiac pathologies on cardiac MR images. The diagnostic performance of T1 mapping alone is particularly of note since it does not require a contrast agent and can be acquired quickly.

Muscle forces acting on the greater trochanter lead to a dorsal warping of the apophyseal growth plate.

The apophyseal growth plate of the greater trochanter, unlike most other growth plates of the human body, exhibits a curved morphology that results in a divergent pattern resembling an open crocodile mouth on plain antero-posterior radiographs. To quantify the angular alignment of the growth plate and to draw conclusions about the function of the muscles surrounding it, we analyzed 57 MRI images of 51 children and adolescents aged 3-17 years and of six adults aged 18-52 years. We measured the angulation of the plate relative to the horizontal plane (AY angle) and the trajectories of the muscles attaching to the greater trochanter of the proximal femur. From anterior to posterior, the AY angle shows a decrease of 33.44°. In the anterior third, the cartilage is angled at a mean of 51.64°, and in the posterior third, the mean angulation is 18.6°. This indicates that the cartilage in the anterior region of the greater trochanteric apophysis is subject to more vertically oriented force vectors compared to the posterior region, as the growth plates align perpendicular to the force vectors acting on them. Combining the measured muscle trajectories with the physiological cross-sectional areas (PCSA) available from the literature revealed that, in addition to the known internal and external lateral traction ligament systems, a third, dorsally located traction ligament system exists that may be responsible for the dorsal deformation of the AY angle.

Transjugular intrahepatic portosystemic shunt creation (TIPS) in the angio-CT-a hybrid intervention with image fusion.

OBJECTIVE: For transjugular intrahepatic portosystemic shunt (TIPS) creation, ultrasound guidance for portal vein puncture is strongly recommended. However, outside regular hours of service, a skilled sonographer might be lacking. Hybrid intervention suites combine CT imaging with conventional angiography allowing to project 3D information into the conventional 2D imaging and further CT-fluoroscopic puncture of the portal vein. The purpose of this study was to assess whether TIPS using angio-CT facilitates the procedure for a single interventional radiologist. METHODS: All TIPS procedures from 2021 and 2022 which took place outside regular working hours were included (n = 20). Ten TIPS procedures were performed with just fluoroscopy guidance and ten procedures using angio-CT. For the angio-CT TIPS, a contrast-enhanced CT was performed on the angiography table. From the CT, a 3D volume was created using virtual rendering technique (VRT). The VRT was blended with the conventional angiography image onto the live monitor and used as guidance for the TIPS needle. Fluoroscopy time, area dose product, and interventional time were assessed. RESULTS: Hybrid intervention with angio-CT did lead to a significantly shorter fluoroscopy time and interventional time (p = 0.034 for both). Mean radiation exposure was significantly reduced, too (p = 0.04). Furthermore, the mortality rate was lower in patients who underwent the hybrid TIPS (0% vs 33%). CONCLUSION: TIPS procedure in angio-CT performed by only one interventional radiologist is quicker and reduces radiation exposure for the interventionalist compared to mere fluoroscopy guidance. The results further indicate increased safety using angio-CT. CLINICAL RELEVANCE STATEMENT: This study aimed to evaluate the feasibility of using angio-CT in TIPS procedures during non-standard working hours. Results indicated that the use of angio-CT significantly reduced fluoroscopy time, interventional time, and radiation exposure, while also leading to improved patient outcomes. KEY POINTS: • Image guiding such as ultrasound is recommended for transjugular intrahepatic portosystemic shunt creation but might be not available for emergency cases outside of regular working hours. • Transjugular intrahepatic portosystemic shunt creation using an angio-CT with image fusion is feasible for only one physician under emergency settings and results in lower radiation exposure and faster procedures. • Transjugular intrahepatic portosystemic shunt creation using an angio-CT with image fusion seems to be safer than using mere fluoroscopy guidance.

Safety of sheathless vascular access using braided 4 F selective catheters for common body interventions - a retrospective study.

BACKGROUND: Besides other factors, complication rate of transarterial interventions depends on the size of the vascular access. Therefore, the vascular access is mostly chosen as small as possible while still allowing all planned parts of the intervention. This retrospective analysis is to evaluate the safety and feasibility of sheathless arterial interventions for a broad spectrum of interventions in daily practice. METHODS: All sheathless interventions using a 4 F main catheter between May 2018 and September 2021 were included in the evaluation. Additionally, intervention parameters such as type of catheter, use of microcatheter and required change of main catheters were assessed. Information about the use about sheathless approach and catheters were obtained from the material registration system. All catheters were braided. RESULTS: 503 sheathless interventions with 4 F catheters from the groin were documented. The spectrum comprised bleeding embolization, diagnostic angiographies, arterial DOTA-TATE-therapy, uterine fibroid embolization, transarterial chemotherapy, transarterial radioembolization and others. In 31 cases (6 %) a change of the main catheter was required. In 381 cases (76 %) a microcatheter was utilized. No clinically relevant adverse events were observed (grade 2 or higher [CIRSE AE-classification]). None of the cases later required conversion to a sheath-based intervention. CONCLUSIONS: Sheathless interventions with a 4 F braided catheter from the groin are safe and feasible. It allows for a broad spectrum of interventions in daily practice.

Impact of Dynamic Contrast Enhanced and Diffusion-Weighted MR Imaging on Detection of Early Local Recurrence of Soft Tissue Sarcoma.

BACKGROUND: Diagnosis of residual or recurrent tumor in soft-tissue sarcomas (STS) is a differential diagnostic challenge since post-therapeutic changes impede diagnosis. PURPOSE: To evaluate the diagnostic accuracy of quantitative dynamic contrast enhanced (DCE)-MRI and diffusion-weighted imaging (DWI) to detect local recurrence of STS of the limb. STUDY TYPE: Prospective. POPULATION: A totalof 64 consecutive patients with primary STS of the limbs were prospectively included 3-6 months after surgery between January 2016 and July 2021. FIELD STRENGTH/SEQUENCE: A 1.5 T; axial DWI echo-planar imaging sequences and DCE-MRI using a 3D T1-weighted spoiled gradient-echo sequence. ASSESSMENT: The quantitative DCE-MRI parameters relative plasma flow (rPF) and relative mean transit time (rMTT) were calculated and ADC mapping was used to quantify diffusion restriction. Regions of interest of tumor growth and postoperative changes were drawn in consensus by two experts for diffusion and perfusion analysis. An additional morphological assessment was done by three independent and blinded radiologists. STATISTICAL TEST: Unpaired t-test, ROC-analysis, and a logistic regression model were applied. Interobserver reliability was calculated using Fleiss kappa statistics. A P value of 0.05 was considered statistically significant. RESULTS: A total of 11 patients turned out to have local recurrence. rPF was significantly higher in cases of local recurrence when compared to cases without local recurrence (61.1-4.5) while rMTT was slightly and significantly lower in local recurrence. ROC-analysis showed an area under the curve (AUC) of 0.95 (SEM ± 0.05) for rPF while a three-factor multivariate logistic regression model showed a high diagnostic accuracy of rPF (R2  = 0.71). Compared with morphological assessment, rPF had a distinct higher specificity and true positive value in detection of LR. DATA CONCLUSION: DCE-MRI is a promising additional method to differentiate local recurrence from benign postoperative changes in STS of the limb. Especially specificity in detection of LR is increased compared to morphological assessment. EVIDENCE LEVEL: 1 TECHNICAL EFFICACY: Stage 2.

Efficacy of ultrasound assisted catheter-directed thrombolysis compared to catheter-directed thrombolysis in vitro.

BACKGROUND: Catheter-directed thrombolysis (CDT) is an effective and safe endovascular method used in critical limb ischemia and many other thromboembolic events. Ultrasound-assisted catheter-directed thrombolysis (US-CDT) is an emerging technique considered to accelerate thrombolysis and therefore is supposed to improve outcome. PURPOSE: To evaluate the efficacy of US-CDT in comparison to standard CDT in vitro. MATERIAL AND METHODS: A total of 69 sets of human venous blood were evaluated, each comprising a tube just treated with CDT, a tube treated with US-CDT, and a control tube. All tubes were kept under physiological conditions. Except for the controls, in all tubes 5 mg of tissue-type plasminogen activator was administered over the predetermined treatment interval. Thrombus mass was weighted at the end of the lysis intervals at 6 h or 24 h, respectively. RESULTS: CDT led to a mean thrombus reduction of 32% and ultrasound-assisted lysis led to a mean thrombus reduction of 41% (P < 0.001 for both). Thrombus reduction was significantly higher after US-CDT compared to CDT (P = 0.001). The better efficacy of US-CDT was mostly already apparent at early phases during thrombolysis and did further mildly increase over time (r = 0.24; P = 0.047). CONCLUSION: In vitro US-CDT is significantly superior to standard CDT; this effect is apparent at an early timepoint of lysis and slightly further increases over time.

[Imaging of intrahepatic cholangiocarcinoma : Reliable diagnosis according to the new S3 guideline]. / Bildgebung beim intrahepatischen Cholangiokarzinom : Richtige Diagnostik nach der neuen S3-Leitlinie.

The S3 guideline on hepatocellular carcinoma has been expanded to include malignant biliary carcinoma (synonym cholangiocarcinoma [CCA]). Magnetic resonance imaging (MRI) with additional magnetic resonance cholangiopancreatography (MRCP) is the imaging modality of choice to evaluate local findings. Use of gadolinium ethoxybenzyl diethylenetriamine penta-acetic acid (Gd-EOB-DTPA)-based contrast agent increases its diagnostic value. Histologic confirmation is always required when diagnosing intrahepatic CCA (iCCA) because using imaging alone there is a risk of confusion with HCC subtypes.

Outcome and Safety after 103 Radioembolizations with Yttrium-90 Resin Microspheres in 73 Patients with Unresectable Intrahepatic Cholangiocarcinoma-An Evaluation of Predictors.

Trans-arterial radioembolization (TARE) is increasingly evaluated for unresectable intrahepatic cholangiocarcinoma (ICC). Not all ICC patients benefit equally well from TARE. Therefore, we sought to evaluate variables predicting progression-free survival (PFS) and overall survival (OS). Patients with non-resectable ICC underwent TARE and were treated with 90Y resin microspheres. Baseline characteristics, biochemical/clinical toxicities, and response were examined for impact on PFS and OS. A total of 103 treatments were administered to 73 patients without major complications or toxicity. Mean OS was 18.9 months (95% confidence intervals (CI); 13.9-23.9 months). Mean and median PFS were 10.1 months (95% CI; 7.9-12.2) and 6.4 months (95% CI; 5.20-7.61), respectively. Median OS and PFS were significantly prolonged in patients with baseline cholinesterase (CHE) ≥ 4.62 kU/L (OS: 14.0 vs. 5.5 months; PFS: 6.9 vs. 3.2 months; p < 0.001). Patients with a tumor burden ≤ 25% had a significantly longer OS (15.2 vs. 6.6 months; p = 0.036). Median PFS was significantly longer for patients with multiple TARE cycles (24.4 vs. 5.8 months; p = 0.04). TARE is a considerable and safe option for unresectable ICC. CA-19-9, CHE, and tumor burden have predictive value for survival in patients treated with TARE. Multiple TARE treatments might further improve survival; this has to be confirmed by further studies.

Risk factors assessment for radiographically guided port implantations with forearm access.

INTRODUCTION: Port implantations at the forearm are associated with an increased risk of relevant vein thrombosis. Therefore, with this study we sought to identify the responsible risk factors to improve technical quality of the method. METHODS: This is a retrospective analysis of 313 patients with port implantation at the forearm in 2019. Then, exploratory statistics were conducted comprising Cox-Regression and Kaplan-Meier-Analyses. RESULTS: Mean age was 60 ± 14 years. 232 (74%) of the patients were female. No early infection was observed. 29 late infections and 57 cases of thrombosis occurred. In only 9% of the patients with thrombosis hospital admission was necessary for treatment. Median interval to the diagnosis of thrombosis was 23 days; inter-quartile-range: 16-75. Mean interval to elective port explantation was 227 ± 128 days. There was no effect of occurrence of thrombosis of the interventionalist, the assistance nor of several technical aspects. However, there was a significantly lower risk of thrombosis for primary implanted port system compared to replacement ports, Hazard-ratio: 0.34 [Confidence interval: 0.172, 0.674], p = 0.002. Age was a significant risk factor for late infections, Hazard-ratio: 3.35 [Confidence interval:1.84, 6.07], p < 0.0001. CONCLUSION: The main risk factor for adverse outcome after radiographically guided port implantation at the forearm is the type of the implanted port system. The reason for that might not be the material itself but the experience of a team with a certain port system. Age is a risk factor for late complications.

Multiscale X-ray phase contrast imaging of human cartilage for investigating osteoarthritis formation.

BACKGROUND: The evolution of cartilage degeneration is still not fully understood, partly due to its thinness, low radio-opacity and therefore lack of adequately resolving imaging techniques. X-ray phase-contrast imaging (X-PCI) offers increased sensitivity with respect to standard radiography and CT allowing an enhanced visibility of adjoining, low density structures with an almost histological image resolution. This study examined the feasibility of X-PCI for high-resolution (sub-) micrometer analysis of different stages in tissue degeneration of human cartilage samples and compare it to histology and transmission electron microscopy. METHODS: Ten 10%-formalin preserved healthy and moderately degenerated osteochondral samples, post-mortem extracted from human knee joints, were examined using four different X-PCI tomographic set-ups using synchrotron radiation the European Synchrotron Radiation Facility (France) and the Swiss Light Source (Switzerland). Volumetric datasets were acquired with voxel sizes between 0.7 × 0.7 × 0.7 and 0.1 × 0.1 × 0.1 µm3. Data were reconstructed by a filtered back-projection algorithm, post-processed by ImageJ, the WEKA machine learning pixel classification tool and VGStudio max. For correlation, osteochondral samples were processed for histology and transmission electron microscopy. RESULTS: X-PCI provides a three-dimensional visualization of healthy and moderately degenerated cartilage samples down to a (sub-)cellular level with good correlation to histologic and transmission electron microscopy images. X-PCI is able to resolve the three layers and the architectural organization of cartilage including changes in chondrocyte cell morphology, chondrocyte subgroup distribution and (re-)organization as well as its subtle matrix structures. CONCLUSIONS: X-PCI captures comprehensive cartilage tissue transformation in its environment and might serve as a tissue-preserving, staining-free and volumetric virtual histology tool for examining and chronicling cartilage behavior in basic research/laboratory experiments of cartilage disease evolution.

[Comparison of radiation exposure in common hepatic interventions : A retrospective analysis of DeGIR registry data]. / Strahlenexposition bei häufigen interventionellen Eingriffen der Leber im Vergleich : Retrospektive Analyse von DeGIR-Registerdaten.

BACKGROUND: Transcatheter arterial chemoembolization (TACE) and biliary interventions are common procedures. OBJECTIVES: In this retrospective study, the radiation exposure of patients undergoing hepatic intervention will be analyzed and compared depending on the type and objective of the intervention. MATERIALS AND METHODS: This is an analysis of 7003 data sets of performed TACEs and biliary interventions from the DeGIR registry for the years 2016, 2017, and 2018. The dose area product (DAP), fluoroscopy time (FT), type of intervention, and anatomically defined target were recorded. RESULTS: Data with documented radiation doses were available for 4985 TACEs and for 2018 biliary interventions. For biliary interventions the median DAP was 2594 (interquartile range [IQR] = 1174-5858) cGycm2. For TACE, the median DAP was 11,632 [IQR = 5530-22,800] cGycm2 and significantly higher compared to biliary interventions (p < 0.0001). Biliary interventions with the highest DAP take place at the common hepatic duct; procedures with the longest FT were registered at the hepatic duct bifurcation. CONCLUSIONS: The individual radiation exposure during liver interventions is less dependent of the complexity of the procedure or the fluoroscopy time, but rather on the type of intervention and the anatomic target. The presented data can help to approximately estimate the radiation exposure in advance when planning an intervention.

Is bone marrow edema syndrome a precursor of hip or knee osteonecrosis? Results of 49 patients and review of the literature.

PURPOSE: Diagnosis of bone marrow edema syndrome (BMES) can be challenging. There is sometimes uncertainty about the correct diagnosis of BMES on morphologic magnetic resonance imaging (MRI), since subchondral findings like lines and spots can be misinterpreted as "beginning" or "possible" avascular osteonecrosis (AVN). The aim of our study was to systematically assess the temporal course of BMES from first diagnosis on MRI until the end of clinical symptoms and the full disappearance of bone marrow edema (BME) to determine whether subchondral lines and spots detected in these patients can develop into osteonecrosis. METHODS: In a combined retrospective and prospective study, we retrieved serial MRI scans of hips and knees with BME from the hospital database. According to clinical and imaging data, all patients with degenerative, infectious/inflammatory, rheumatic, neoplastic conditions and those showing typical osteonecrosis were excluded. We collected all available MRI examinations from first detection of BME until its disappearance. In case edema had not fully resolved in the last available MRI scan, we performed an MRI with an additional dynamic contrast-enhanced (DCE-MRI) sequence. For each MRI scan, we recorded the severity of edema, the presence of subchondral hypointense lines and the presence of subchondral focal hypointense zones on T1-weighted images by two independent readers. The DCE-MRI scans were used to calculate parameter maps to assess the perfusion characteristics. RESULTS: The study comprised 49 patients aged 22-71 years. In total, 171 morphologic and 5 DCE-MRI scans were evaluated. In 44 patients (89.8%), the BMES completely healed without remnants. In 18 of 49 patients (36.7%), a subchondral line was present in the first MRI exam. Nine patients (18.4%) developed a subchondral line within 1-5 months after the first MRI. In total, 27 out of 49 patients (55.1%) had subchondral lines (12 knees, 15 hips) during the timeframe of the study. All subchondral lines disappeared in the timeframe of the study. Subchondral focal hypointense zones were present in 14 out of 49 patients (28.6%): in 9 cases, subchondral focal hypointense zones disappeared after a median of 5.5 months (range, 1-85 months), while in 5 cases, subchondral focal lesions persisted until the end of the study (up to more than 85 months) without edema in the surrounding bone. All persisting subchondral focal lesions were hyperperfused. These 5 patients had associated meniscal lesions. CONCLUSION: Our study shows that subchondral lines and spots found in patients with BMES do not develop into AVN. Subchondral lines, which resemble subchondral insufficiency fractures, are associated with BMES. Subchondral focal T1-hypointense zones do not represent AVN; most probably these areas represent reparative processes within the subchondral bone, where tensile and shear force overload is present due to altered biomechanics.

Quantitative Assessment of Degenerative Cartilage and Subchondral Bony Lesions in a Preserved Cadaveric Knee: Propagation-Based Phase-Contrast CT Versus Conventional MRI and CT.

OBJECTIVE: The aim of this study was to quantitatively assess hyaline cartilage and subchondral bone conditions in a fully preserved cadaveric human knee joint using high-resolution x-ray propagation-based phase-contrast imaging (PBI) CT and to compare the performance of the new technique with conventional CT and MRI. MATERIALS AND METHODS: A cadaveric human knee was examined using an x-ray beam of 60 keV, a detector with a 90-mm2 FOV, and a pixel size of 46 × 46 µm2. PBI CT images were reconstructed with both the filtered back projection algorithm and the equally sloped tomography method. Conventional 3-T MRI and CT were also performed. Measurements of cartilage thickness, cartilage lesions, International Cartilage Repair Society scoring, and detection of subchondral bone changes were evaluated. Visual inspection of the specimen akin to arthroscopy was conducted and served as a standard of reference for lesion detection. RESULTS: Loss of cartilage height was visible on PBI CT and MRI. Quantification of cartilage thickness showed a strong correlation between the two modalities. Cartilage lesions appeared darker than the adjacent cartilage on PBI CT. PBI CT showed similar agreement to MRI for depicting cartilage substance defects or lesions compared with the visual inspection. The assessment of subchondral bone cysts showed moderate to strong agreement between PBI CT and CT. CONCLUSION: In contrast to the standard clinical methods of MRI and CT, PBI CT is able to simultaneously depict cartilage and bony changes at high resolution. Though still an experimental technique, PBI CT is a promising high-resolution imaging method to evaluate comprehensive changes of osteoarthritic disease in a clinical setting.

Fracture generation in human vertebrae under compression loading: The influence of pedicle preservation and bone mineral density on in vitro fracture behavior.

BACKGROUND: Fractured vertebral bodies are a common and wide spread health issue. OBJECTIVE: The purpose of this study was to develop a standardized method to experimentally generate compression fractures in vertebral bodies. The influence of the pedicles has been investigated with regards to the fracture behavior. The correlation between bone mineral density (BMD), the cause of fractures and the fracture behavior was investigated. METHODS: Twenty-one fresh frozen human lumbar spines were examined for bone mineral density (BMD) by means of quantitative computed tomography (qCT). All soft tissue was removed, vertebrae were carefully separated from each other and the exposed cranial and caudal endplates were covered with a thin layer of resin to generate a plane and homogeneous surface. A total of 80 vertebral bodies were tested until fracture. RESULTS: A good positive correlation was found between BMD, fracture compression force and stiffness of the vertebral body. No significant differences were found between the fractures generated in vertebral bodies with and without pedicles, respectively. CONCLUSIONS: Our model represents a consolidation of already existing testing devices. The comparative measurement of the BMD and the fracture behavior shows validity. In contrast to other authors, the force was applied to the whole vertebral body. Furthermore the upper and lower plates were not parallelized and therefore the natural anatomic shape was imitated. Fracture behavior was not altered by removing the pedicles.

Diffusion imaging of the vertebral bone marrow.

Diffusion-weighted MRI (DWI) of the vertebral bone marrow is a clinically important tool for the characterization of bone-marrow pathologies and, in particular, for the differentiation of benign (osteoporotic) and malignant vertebral compression fractures. DWI of the vertebral bone marrow is, however, complicated by some unique MR and tissue properties of vertebral bone marrow. Due to both the spongy microstructure of the trabecular bone and the proximity of the lungs, soft tissue, or large vessels, substantial magnetic susceptibility variations occur, which severely reduce the magnetic field homogeneity as well as the transverse relaxation time T*2 , and thus complicate MRI in particular with echoplanar imaging (EPI) techniques. Therefore, alternative diffusion-weighting pulse sequence types such as single-shot fast-spin-echo sequences or segmented EPI techniques became important alternatives for quantitative DWI of the vertebral bone marrow. This review first describes pulse sequence types that are particularly important for DWI of the vertebral bone marrow. Then, data from 24 studies that made diffusion measurements of normal vertebral bone marrow are reviewed; summarizing all results, the apparent diffusion coefficient (ADC) of normal vertebral bone marrow is typically found to be between 0.2 and 0.6 × 10-3 mm2 /s. Finally, DWI of vertebral compression fractures is discussed. Numerous studies demonstrate significantly greater ADCs in osteoporotic fractures (typically between 1.2 and 2.0 × 10-3 mm2 /s) than in malignant fractures or lesions (typically 0.7-1.3 × 10-3 mm2 /s). Alternatively, several studies used the (qualitative) image contrast of diffusion-weighted acquisitions for differentiation of lesion etiology: a very good lesion differentiation can be achieved, particularly with diffusion-weighted steady-state free precession sequences, which depict malignant lesions as hyperintense relative to normal-appearing vertebral bone marrow, in contrast to hypointense or isointense osteoporotic lesions. Copyright © 2015 John Wiley & Sons, Ltd.

Transient Bone Marrow Edema Syndrome versus Osteonecrosis: Perfusion Patterns at Dynamic Contrast-enhanced MR Imaging with High Temporal Resolution Can Allow Differentiation.

Purpose To prospectively evaluate the perfusion patterns at quantitative dynamic contrast material-enhanced (DCE) magnetic resonance (MR) imaging of transient bone marrow edema syndrome (TBMES) and avascular osteonecrosis. Materials and Methods Institutional review board approval and written informed consent were obtained. Thirty-two patients (21 men, 11 women; mean age, 48 years; 26 hips, 10 knees) underwent conventional MR imaging and a dynamic contrast-enhanced three-dimensional spoiled gradient-echo sequence at 3 T. Parameter maps for mean transit time (MTT) and plasma flow (PF) were evaluated qualitatively and quantitatively. Differences in perfusion patterns were analyzed by using the Fisher exact test. Regions of interest were drawn in areas of high PF and long MTT on each parametric map. Mean, median, standard deviation, minimum, and maximum values were determined. TBMES and osteonecrosis were compared statistically by using the Mann-Whitney U and Wilcoxon signed-rank tests, with a P value of less than .05 considered indicative of a significant difference. Results Nineteen joints with TBMES and 17 joints with osteonecrosis were evaluated. TBMES joints showed a subchondral elongated area of high PF and low MTT that was surrounded by an area of long MTT and low PF. Osteonecrosis joints showed a subchondral area with low or no detectable PF and MTT adjacent to the joint surface, which was surrounded by a rim of high PF and intermediate MTT. Patterns for TBMES and osteonecrosis did not overlap. A significant difference (P < .001) in PF in the immediate subchondral area was found between TBMES and osteonecrosis; in joints with osteonecrosis, this was comparable to background noise, and therefore, could not be quantified. In the circumscribed rim of high PF and intermediate MTT, which was only found in joints with osteonecrosis, mean ± standard deviation PF was 18.9 mL/100 mL per minute ± 11.0 and mean MTT was 213.3 seconds ± 56.8. No significant difference between TBMES and osteonecrosis was found for MTT (P = .09) and PF (P = .75) in the surrounding area. Conclusion Parameter maps derived at dynamic contrast-enhanced MR imaging with high temporal resolution can allow differentiation of osteonecrosis from TBMES in hip and knee joints. © RSNA, 2016 Online supplemental material is available for this article.

CT fluoroscopy-guided closed-tip catheter placement before regional hyperthermia treatment of soft tissue sarcomas: 5-Year experience in 35 consecutive patients.

PURPOSE: This study was designed to assess technical success and complications in patients with high-risk soft tissue sarcomas undergoing CT fluoroscopy-guided closed-tip catheter placement before treatment with combined chemotherapy and regional hyperthermia. MATERIALS AND METHODS: This retrospective study comprised all patients referred for insertion of closed-tip catheters for the introduction of thermometry probes before regional hyperthermia treatment at a single university centre from 2010 to 2015. Catheter placements were performed under local anaesthesia and intermittent CT fluoroscopy guidance. Technical success, complication rate, duration of catheter insertion and dose-length product (DLP) were analysed. Technical success was defined as intratumoural catheter placement suitable for subsequent thermometry. RESULTS: A total of 35 procedures were performed on 35 patients (22 men, 13 women). In 34 out of 35 interventions catheters were inserted successfully; in one patient catheter placement was not feasible. No intra-interventional complications occurred. In six patients post-interventional complications were observed - two major (one abscess formation and one severe catheter dislocation) and four minor complications. Technical failure was observed in 11.4% of patients, especially catheter kinking. A total of 55 catheters were placed, with a mean number of 1.7 ± 0.7 per patient. Mean total DLP was 723.2 ± 355.9 mGy*cm. CONCLUSION: CT fluoroscopy-guided closed-tip catheter placement into high-risk soft tissue sarcomas was characterised by high technical success and relatively low complication rate. While major complications were rarely observed, catheter-kinking preventing successful thermometry represented the most frequent technical failure.

Physiological Background of Differences in Quantitative Diffusion-Weighted Magnetic Resonance Imaging Between Acute Malignant and Benign Vertebral Body Fractures: Correlation of Apparent Diffusion Coefficient With Quantitative Perfusion Magnetic Resonance Imaging Using the 2-Compartment Exchange Model.

OBJECTIVE: To test the hypothesis that apparent diffusion coefficient (ADC) in vertebral bone marrow of benign and malignant fractures is related to the volume of the interstitial space, determined with dynamic contrast-enhanced (DCE) magnetic resonance imaging. METHODS: Patients with acute benign (n = 24) and malignant (n = 19) vertebral body fractures were examined at 1.5 T. A diffusion-weighted single-shot turbo-spin-echo sequence (b = 100 to 600 s/mm) and DCE turbo-FLASH sequence were evaluated. Regions of interest were manually selected for each fracture. Apparent diffusion coefficient was determined with a monoexponential decay model. The DCE magnetic resonance imaging concentration-time curves were analyzed using a 2-compartment tracer-kinetic model. RESULTS: Apparent diffusion coefficient showed a significant positive correlation with interstitial volume in the whole study population (Pearson r = 0.66, P < 0.001), as well as in the malignant (Pearson r = 0.64, P = 0.004) and benign (Pearson r = 0.52, P = 0.01) subgroup. A significant correlation between ADC and the permeability-surface area product could be observed when analyzing the whole study population (Spearman rs = 0.40, P = 0.008), but not when separately examining the subgroups. Plasma flow showed a significant correlation with ADC in benign fractures (Pearson r = 0.23, P = 0.03). Plasma volume did not show significant correlations with ADC. CONCLUSIONS: The results support the hypothesis that the ADC of a lesion is inversely correlated to its cellularity. This explains previous observations that ADC is reduced in more malignant lesions.