Tibiopedal and distal femoral retrograde vascular access for challenging chronic total occlusions: predictors for technical success, and complication rates in a large single-center cohort.

OBJECTIVE: To evaluate the safety and effectiveness of tibiopedal and distal femoral access for retrograde crossing of chronic total occlusion (CTO) in Rutherford stage III to VI peripheral arterial occlusive disease, and to determine factors that correlate with technical success. MATERIAL AND METHODS: One hundred seventy-one consecutive patients were included in this retrospective study. Rutherford stages were III, IV, and V/VI in 24%, 8%, and 67% of patients. Inclusion criteria were CTO at the superficial femoral (SFA), popliteal (PA), and/or below-the-knee (BTK) level, and a failed antegrade treatment followed by a distal retrograde approach. The numbers of occluded vascular levels (OVL), lesion length, degree of calcification, technical success rate, complications, and clinical outcome were noted. RESULTS: OVL were 1 in 72%, 2 in 20%, and 3 in 8% of patients. CTOs were longer than 20 cm in 45.6% of cases and showed severe calcifications in 50.3%. Target vessels for distal access were the distal SFA/PA in 17% and BTK in 83%. The overall technical success rate was 82%. Severe calcification decreased technical success (p = 0.01) despite lesion length and Rutherford stage. Clinical outcome improved in 123/152 patients with a significant increase of the median ABI (N = 158) from 0.53 (interquartile range 0.39 to 0.61) to 0.85 (0.59 to 1.03; p < 0.001). Complications were reported in 7.6% cases with 2.3% related to the distal vascular access. CONCLUSION: The tibiopedal and distal femoral retrograde access presents a safe and effective treatment option of CTOs at the thigh and/or BTK after a failed antegrade attempt improving clinical outcome. Technical success decreased with lesion's degree of calcification. KEY POINTS: • Safety and effectiveness of the tibiopedal and distal femoral access for retrograde crossing of chronic total occlusion. • Target lesion's degree of calcification decreases technical success. • Complications related to the distal vascular access were rare.

Predictive performance of the mHAP-II score in a real-life western cohort with hepatocellular carcinoma following trans-arterial chemoembolisation with drug-eluting beads (DEB-TACE).

OBJECTIVES: To evaluate the predictive performance of the modified hepatoma arterial embolisation prognostic II (mHAP-II) score in a real-life western hepatocellular carcinoma (HCC) cohort treated with drug-eluting bead-TACE and compare the mHAP-II with other scores in this cohort. METHODS: One hundred seventy-nine HCC patients (mean age 77 (± 9) years, 87% male) with one or more drug-eluting bead (DEB)-TACE sessions using 100-300 µm microspheres were retrospectively analysed. Performance analysis of the mHAP-II score was based on Mann-Whitney U tests, the Kaplan-Meier method, log-rank tests, receiver operating characteristics, Akaike's information criterion and Cox regression models. RESULTS: In this population, HCC risk factors were mainly alcohol abuse (31%) and hepatitis C (28%). The median survival of the entire cohort was 29.4 months. mHAP-II classification of the cohort was mHAP-II B (30%), C (41%) and D (23%) respectively. Survival of all subgroups differed significantly from each other (each p < 0.05). Area under the curve for receiver operating characteristic was 0.60 and Akaike's information criterion was 21.8 (p = 0.03), indicating a superior performance of mHAP-II score compared with HAP score and BCLC. Tumour number ≥ two (HR 1.54), alpha-fetoprotein > 400 µg/l (HR 1.14), serum albumin < 3.6 g/dl (HR 1.63) and total bilirubin > 0.9 mg/dl (HR 1.58) contributed significantly in Cox proportional hazards regression (each p < 0.05). CONCLUSION: The mHAP-II score can predict survival outcomes of western HCC patients undergoing DEB-TACE and further subdivide this heterogeneous group; however, certain limitations concerning the predictive power of mHAP-II score must be taken into account. KEY POINTS: • This retrospective study evaluated the predictive performance of the modified hepatoma arterial embolisation prognostic II (mHAP-II) score in a real-life western HCC cohort treated with drug-eluting bead-TACE. • Survival of all mHAP-II subgroups differed significantly, area under the curve for mHAP-II was 0.60 and Akaike's information criterion was 21.8. • The mHAP-II score can predict survival outcomes of western HCC patients undergoing DEB-TACE and further subdivide this heterogeneous group. However, because the study is underpowered, true survival prediction may be more difficult to infer.

Transarterial Chemoembolization of Hepatocellular Carcinoma Using Radiopaque Drug-Eluting Embolics: How to Pursue Periprocedural Cross-Sectional Imaging?

PURPOSE: To compare different imaging techniques (volume perfusion CT, cone-beam CT, and dynamic gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid-enhanced dynamic contrast-enhanced MR imaging with golden-angle radial sparse parallel MR imaging) in evaluation of transarterial chemoembolization of hepatocellular carcinoma (HCC) using radiopaque drug-eluting embolics (DEE). MATERIALS AND METHODS: MR imaging and CT phantom investigation of radiopaque DEE was performed. In the clinical portion of the study, 13 patients (22 HCCs) were prospectively enrolled. All patients underwent cross-sectional imaging before and after transarterial chemoembolization using 100-300 µm radiopaque DEE. Qualitative assessment of images using a Likert scale was performed. RESULTS: In the phantom study, CT-related beam-hardening artifacts were markedly visible at a concentration of 12% (v/v) radiopaque DEE; MR imaging demonstrated no significant detectable signal intensity changes. Imaging obtained before transarterial chemoembolization showed no significant difference regarding tumor depiction. Visualization of tumor feeding arteries was significantly improved with volume perfusion CT (P < .001) and cone-beam CT (P = .002) compared with MR imaging. Radiopaque DEE led to significant decrease in tumor depiction (P = .001) and significant increase of beam-hardening artifacts (P = .012) using volume perfusion CT before versus after transarterial chemoembolization. Greater residual arterial tumor enhancement was detected with MR imaging (10 HCCs) compared with volume perfusion CT (8 HCCs) and cone-beam CT (6 HCCs). CONCLUSIONS: Using radiopaque DEE, the imaging modalities provided comparable early treatment assessment. In HCCs with dense accumulation of radiopaque DEE, treatment assessment using volume perfusion CT or cone-beam CT may be impaired owing to resulting beam-hardening artifacts and contrast stasis. Dynamic contrast-enhanced MR imaging may add value in detection of residual arterial tumor enhancement.

Cost analysis of a wait-and-see strategy after radiochemotherapy in distal rectal cancer.

BACKGROUND: Nonoperative management (NOM) of rectal cancer after radiochemotherapy (RtChx) in patients with a clinical complete response is an emerging strategy with the goal to improve quality of life without compromising cure rates. However close monitoring with both magnetic resonance imaging (MRI) and rectoscopy is required for the early detection of possible local regrowths. We therefore performed a cost analysis comparing the costs of immediate surgery with the costs for MRI and rectoscopy during surveillance as in the upcoming CAO/ARO/AIO-16 trial. METHODS: MRIs and rectoscopies of patients with a clinical complete response after RtChx over the course of 5 years were simulated and compared with immediate surgery after RtChx. Transition probabilities between health stages (no evidence of disease, local regrowth and salvage surgery, distant failure) were derived from the literature. Costs for ambulatory imaging and endoscopic studies were calculated according to the "Gebührenordnung für Ärzte" (GOÄ), costs for surgery based on the diagnosis-related groups system. Three different scenarios with higher costs for salvage surgery or higher regrowth rates were simulated. RESULTS: A patient without disease recurrence will generate costs for MRI and rectoscopy of 6344 € over 5 years compared with costs of 14,511 € for immediate radical surgery. When 25% local regrowths with subsequent salvage surgery were included in the model, the average costs per patient are 8299 €. In our simulations a NOM strategy was cost-saving compared with immediate surgery in all three scenarios. CONCLUSION: A NOM strategy with an intensive surveillance using MRI and rectoscopy will produce costs that are expected to remain below those of immediate surgery.

MR arthrography of the hip: diagnostic performance and image quality of 3D-steady state free precession versus 2D turbo spin echo sequences.

OBJECTIVE: To retrospectively compare the diagnostic performance of isotropic 3D steady-state free precession (3D-SSFP) sequences with 2D turbo spin-echo proton density-weighted fat-saturated (2D-TSE-PD fs) images in hip magnetic resonance arthrography; arthroscopy was a standard of reference. METHODS: Eighty-one patients with suspected labral tears who underwent hip MR arthrography (3-T scanner) were included. 2D-TSE-PD fs sequences were acquired in three planes and a singular sagittal 3D-SSFP. Labral tears, cartilage pathology and bone marrow were independently assessed by two blinded radiologists using a 5-point Likert scale. Accuracy was determined in 39 patients using invasive arthroscopy. RESULTS: Diagnostic confidence of labral and cartilaginous pathologies based on image quality was rated higher for 3D-SSFP (4.5 ± 0.8; 4.35 ± 0.7; p < 0.0001), but inferior for bone marrow pathology (3.9 ± 0.7; 4.0 ± 0.7; p < 0.0001). In the arthroscopy patients, similar sensitivity (85.9%) but higher specificity (74.4vs.42.9%) and higher positive and negative predictive values were found in 3D-SSFP of labral and cartilage pathologies. CONCLUSIONS: 3D-SSFP in hip magnetic resonance arthrography offers increased accuracy in detecting labral and cartilage pathologies compared with 2D-TSE-PD, while reducing the acquisition time. A drawback of 3D-SSFP was the inferior diagnostic confidence for bone marrow evaluation; thus, 3D-SSFP should be combined with conventional 2D-TSE sequences.

Three-dimensional C-arm CT-guided transjugular intrahepatic portosystemic shunt placement: Feasibility, technical success and procedural time.

OBJECTIVES: Establishment of transjugular intrahepatic portosystemic shunts (TIPS) constitutes a standard procedure in patients suffering from portal hypertension. The most difficult step in TIPS placement is blind puncture of the portal vein. This study aimed to evaluate three-dimensional mapping of portal vein branches and targeted puncture of the portal vein. METHODS: Twelve consecutive patients suffering from refractory ascites by liver cirrhosis were included in this retrospective study to evaluate feasibility, technical success and procedural time of C-arm CT-targeted puncture of the portal vein. As a control, 22 patients receiving TIPS placement with fluoroscopy-guided blind puncture were included to compare procedural time. RESULTS: Technical success could be obtained in 100 % of the study group (targeted puncture) and in 95.5 % of the control group (blind puncture). Appropriate, three-dimensional C-arm CT-guided mapping of the portal vein branches could be achieved in all patients. The median number of punctures in the C-arm CT-guided study group was 2 ± 1.3 punctures. Procedural time was significantly lower in the study group (14.8 ± 8.2 min) compared to the control group (32.6 ± 22.7 min) (p = 0.02). CONCLUSIONS: C-arm CT-guided portal vein mapping is technically feasible and a promising tool for TIPS placement resulting in a significant reduction of procedural time. KEY POINTS: • C-arm CT-mapping of the portal vein for 3D TIPS guidance is feasible. • Targeted punctures of the portal vein by C-arm CT reduce procedural time. • A decreased number of punctures could improve patient safety.

Metastatic patterns and metastatic sites in mucosal melanoma: a retrospective study.

OBJECTIVES: Melanomas arising from mucosa are rare and associated with a poor prognosis. This study aims to provide an analysis of metastatic pathways, time intervals, factors influencing metastatic spread and organs for distant metastases. METHODS: A total of 116 patients with mucosal melanomas of different sites were included. The mean follow-up interval was 47 ± 52 months. Patients were assigned to two different metastatic pathways, either presenting loco-regional lymph node metastases as first spread or direct distant metastases. The distribution of distant metastases was assessed. RESULTS: Twenty-six patients presented with a pre-existing metastatic spread and were not assigned to pathways. Of the included patients, 44 developed metastases after treatment of the primary tumour; 25 patients directly developed distant metastases; 16 patients developed regional lymph node metastases prior to distant metastases. Location of the primary tumour in the upper airway or GI tract and advanced T stage were significant risk factors of direct distant metastases. Distant metastases are mainly located in the lung, the liver and non-regional lymph nodes. CONCLUSIONS: Mucosal melanomas show a high rate of direct distant metastases rather than regional lymph node metastases. Thus the follow-up should always include a whole-body cross-sectional imaging in high-risk tumours. KEY POINTS: • Mucosal melanomas show a high rate of direct distant metastases. • T stage and primary location are predictors for direct distant metastases. • Distant metastases were mainly found in lung, liver and lymph nodes. • Follow-up of a high-risk mucosal melanoma should include whole-body imaging.

Diagnostic value of T1 and T2 * relaxation times and off-resonance saturation effects in the evaluation of Achilles tendinopathy by MRI at 3T.

PURPOSE: To evaluate and compare the diagnostic value of T1 , T2 * relaxation times and off-resonance saturation ratios (OSR) in healthy controls and patients with different clinical and morphological stages of Achilles tendinopathy. MATERIAL AND METHODS: Forty-two healthy Achilles tendons and 34 tendons of 17 patients with symptomatic and asymptomatic tendinopathy were investigated clinically with conventional magnetic resonance imaging (MRI) sequences on a 3T whole-body MR scanner and a dynamic ultrasound examination. In addition, T1 and T2 * relaxation times were assessed using an ultrashort echo time (UTE) imaging sequence with flip angle and echo time variation. For the calculation of OSR values a Gaussian off-resonance saturation pulse (frequency offset: 750-5000 Hz) was used. The diagnostic value of the derived MR values was assessed and compared using receiver operating characteristic (ROC) curves. RESULTS: ROC curves demonstrate the highest overall test performance for OSR values at 2000 Hz off-resonance in differentiating slightly (OSR-2000 [AUC: 0.930] > T2 * [AUC: 0.884] > T1 [AUC: 0.737]) and more severe pathologically altered tendon areas (OSR-2000 [AUC: 0.964] > T2 * [AUC: 0.917] > T1 [AUC: 0.819]) from healthy ones. CONCLUSION: OSR values at a frequency offset of 2000 Hz demonstrated a better sensitivity and specificity for detecting mild and severe stages of tendinopathy compared to T2 * and particularly when compared to T1 relaxation times.

Influence of physical activity on T1 and T2* relaxation times of healthy Achilles tendons at 3T.

PURPOSE: To evaluate longitudinal (T1) and transverse (T2*) relaxation times at different Achilles tendon locations (insertion, mid-portion, and musculotendinous area) in a cohort of subjects with variable tendon straining activity, but without any signs of tendinopathy. MATERIALS AND METHODS: T1 and T2* relaxation times of the Achilles tendon were measured using an ultrashort echo time (UTE) imaging sequence with flip angle and echo time variation on a 3T whole-body clinical magnetic resonance (MR) scanner. Twenty-four tendons of 12 healthy volunteers and 18 tendons of nine healthy recreational long-distance runners (average weekly running distance of 47.4 ± 5.3 km) were enrolled. RESULTS: Mean T1 values of the whole tendon showed no marked group differences, whereas T2* relaxation times of runners were significantly longer (mean percentage increase 15.7 ± 4.9%; P = 0.0181) compared to controls. Regarding group differences for the investigated insertional, mid-portion, and musculotendinous area of the Achilles tendon, only the mid-portion of the Achilles tendon in the running group presented significantly longer T2* values (mean percentage increase 29.1 ± 23.0%; P = 0.0420) in comparison to the control group. CONCLUSION: Prolonged T2* values especially in the mid-portion of the Achilles tendon of runners are likely to reflect an adaptation of the tendon microstructure to repetitive tendon straining activity.

Quantitative Assessment of Iron-Labeled Stem-Cell Adhesion at the Vessel Wall in a Vascular Flow Model: Correlation of T2*-Weighted Imaging at 3 T and Histology.

PURPOSE: To evaluate the distribution of superparamagnetic iron oxide (SPIO)-labeled cells in a perfused segment of a porcine artery and to estimate the number of adherent cells by means of magnetic resonance (MR) imaging. MATERIALS AND METHODS: Six vessel specimens (diameters between 0.8 and 1.2 cm) were placed in a bioreactor system, and 2 × 10(4) to 1 × 10(6) SPIO-labeled endothelial colony-forming cells were injected into the artery within the perfused reactor. The area of resulting signal extinctions at the inner wall of the vessels was quantified on MR images by using a high-resolution T2*-weighted sequence with a slice-by-slice approach. After imaging, the labeled cells were quantified histologically. RESULTS: The total iron load of each cell was 56.5 pg ± 14.4. In the applied range of 2 × 10(4) to 1 × 10(6) cells per vessel, the area of iron-induced signal extinction at the vessel wall on T2*-weighted imaging corresponded to the histologically detected cell number (r = 0.98, P < .001). CONCLUSIONS: A correlation between the area of signal extinction and the number of labeled cells at the vessel wall was found. This might help to evaluate dose rates in further clinical applications of intravascular cell-based therapies.

Anatomic-functional (perfusion-based) magnetic resonance imaging follow-up in patients with rheumatoid arthritis treated with anti-interleukin 6 antibodies: a comparison with clinical scores and serologic data.

OBJECTIVE: On a 3-T magnetic resonance scanner, morphologic and perfusion changes of 9 patients with rheumatoid arthritis were evaluated after start of anti-interleukin 6 receptor antibody Tocilizumab (TCZ) treatment. METHODS: Morphologic and perfusion-based magnetic resonance imaging (MRI) parameters were assessed before and 4, 12, and 24 after the start of TCZ treatment. Furthermore, serologic biomarkers and clinical assessment scores were evaluated 4, 12, 24, and 52 weeks after treatment initiation. RESULTS: Results of MRI parameters showed significant group differences between responders and nonresponders for synovial volume, transfer constant, and blood plasma volume fraction already at week 12 as well as relative enhancement and rate of early enhancement at week 24. CONCLUSIONS: Considering the temporal change of perfusion-derived MRI parameters (transfer constant, blood plasma volume fraction, relative enhancement, and rate of early enhancement) as well as morphologic MRI parameters (synovial volume measurements), a quantifiable assessment of response to TCZ therapy in rheumatoid arthritis seems possible at an even earlier time point compared with clinical assessment scores, whereas serologic biomarkers proved nonspecific in this respect.

Tendinopathy of the achilles tendon: volume assessed by automated contour detection in submillimeter isotropic 3-dimensional magnetic resonance imaging data sets recorded at a field strength of 3 T.

OBJECTIVE: This prospective study assesses volume changes of the Achilles tendon in case of chronic tendinopathy (TEN), using an automated contour detection algorithm in submillimeter isotropic 3-dimensional magnetic resonance imaging data sets, recorded at 3 T. METHODS: Forty-one subjects (median age, 40 years; range, 19-68 years) were included in this prospective study and underwent nonenhanced magnetic resonance imaging of both Achilles tendons at 3 T, deploying a T2-weighted 3-dimensional Fast-Spin-Echo sequence with submillimeter resolution of 0.8 mm. Of the 41 subjects, 13 were classified as patients with TEN and 28 were healthy volunteers and served as control group. Of the 13 patients, 10 had unilateral TEN and 3 had bilateral TEN. Achilles tendons were automatically segmented in the T2-weighted magnetic resonance data sets for the evaluation of the tendon volume (0-3 cm proximal to the cranial border of the calcaneal bone). The total volume (length, 3 cm) was divided in 3 subvolumes of 1 cm length, named volume (0-1 cm), volume (1-2 cm), and volume (2-3 cm). Minimum and maximum tendon cross-sectional area within the total volume was processed. A standardized pain questionnaire was obtained from all patients. RESULTS: The automated contour detection algorithm worked reliably in all cases. The TEN group showed a significantly increased tendon volume compared to the control group (mean volume, 2.94 vs 2.43 mm; P < 0.05). The difference was most obvious concerning volume (2-3 cm) (P < 0.0001). Evaluation of clinical severity revealed a moderate correlation between VISA-score and tendon volume (2-3 cm) as well as the maximum/minimum tendon area (ρ = -0.44, ρ = -0.48, and ρ = -0.41). In case of unilateral TEN, the symptomatic side showed an increased tendon volume (2-3 cm) and increased minimum area (P < 0.05). CONCLUSIONS: Tendon volume and size are adequate surrogate parameters to differentiate patients with chronic TEN from healthy subjects, and may discriminate symptomatic TEN from asymptomatic "silent" TEN in patients with unilateral symptoms.

Quick water-selective excitation of fast relaxing tissues with 3D UTE sequences.

PURPOSE: The aim of this study was to implement a time effective 1-1 double pulse water-selective excitation (WE) into a three-dimensional ultrashort echo time (UTE) sequence (WE-UTE) for visualization of short-T2 tissues with positive contrast and sufficient suppression of surrounding fat. METHODS: First, an analytical description of magnetization components in the steady state applying WE-UTE was derived and results were compared with numerical simulations based on Bloch's equations. Parameters were optimized for best positive contrast between short-T2 tissues and fat under consideration of variable relaxation properties over a broad range. Maximal signal yield and signal efficiency of on-resonant protons were compared with UTE sequences with and without off-resonance fat saturation (FatSat). WE-UTE was exemplarily applied for in-vivo musculoskeletal imaging on a 3T whole-body MR unit. RESULTS: Steady state magnetization of WE-UTE could be described analytically and showed excellent accordance with numerical simulations. Even for tissues with T2 = 1 ms WE-UTE resulted in 79% of maximal signal yield of UTE without FatSat and was more efficient regarding signal yield if compared with UTE with FatSat. Using WE-UTE in-vivo tendons and ligaments could be well delineated with positive contrast to surrounding fat. CONCLUSION: WE-UTE provides a quick method for visualizing short-T2 tissues with positive contrast.

Perfusion measurements of the calf in patients with peripheral arterial occlusive disease before and after percutaneous transluminal angioplasty using MR arterial spin labeling.

PURPOSE: To evaluate muscle perfusion in patients with peripheral arterial occlusive disease (PAOD) before and after percutaneous transluminal angioplasty (PTA) of the limb by means of MR arterial spin labeling (ASL) perfusion measurements during reactive hyperemia. MATERIALS AND METHODS: Ten patients with symptomatic PAOD affecting the iliac or femoral vessels were investigated before and after PTA. A pseudo-continuous arterial spin labeling (PCASL) MR technique was applied. Perfusion was measured in soleus and tibialis anterior muscle during reactive hyperemia. Key parameters such as mean perfusion value (Phyp ), time-to-peak (TTP) and duration of hyperemia (Thyp ) describing the perfusion signal curve were examined. RESULTS: Between baseline and post-PTA, Phyp increased in both muscle groups. At the same time, TTP and Thyp decreased in both muscle groups. At the same time the clinically assessed ankle brachial index (ABI) increased from 0.56 ± 0.10 to 0.83 ± 0.15. The impaired pain-free walking distance improved in all patients. CONCLUSION: PCASL MRI can detect changes of the key perfusion parameters Phyp , TTP, and Thyp after successful PTA of the calf muscles during reactive hyperemia and seems to be a promising tool for monitoring of interventional treatments.

Short-term exercise-induced changes in hydration state of healthy Achilles tendons can be visualized by effects of off-resonant radiofrequency saturation in a three-dimensional ultrashort echo time MRI sequence applied at 3 Tesla.

PURPOSE: Off-resonant RF saturation influences signal intensity dependent on free and bound water fractions as well as the macromolecular content. The extent of interaction between these compartments can be evaluated by using the off-resonance saturation ratio (OSR). Combined with UTE sequences quantification of OSR even in tendinous tissues with extremely fast signal decay is possible. The aim of this prospective study was to investigate short-term exercise-induced effects of hydration state of the Achilles tendon by means of OSR and tendon volume. MATERIALS AND METHODS: Measurements of OSR and tendon volume before and after ankle-straining activity were performed in seven healthy male volunteers (median age 29 years) using a 3D UTE sequence with implemented off-resonance saturation pulse at 3T (off-resonance frequency 2/3 kHz) and by an automated contour detection in isotropic T2-weighted MR images with sub-millimeter resolution, respectively. Different tendon regions were evaluated. Reproducibility of OSR was measured in subsequent imaging sets. Root-mean-square-deviation (RMSD) and coefficient of variations (CV) were determined. RESULTS: RMSD of OSR in resting position were between 0.006 and 0.01 for different tendon regions and off-resonance frequencies (CV 2 to 3%). A significant increase (P < 0.05) of OSR after exercise was seen in all tendon regions except at the insertion (off-resonance frequency 3 kHz). Tendon volume was decreased significantly after ankle-straining activity (P = 0.003). CONCLUSION: The observed decreased tendon volume and increased OSR directly after exercise indicates a short-term change in tendinous proton compartments, most likely a loss of free water molecules within the tendon.

Impact of endobronchial coiling for lung volume reduction on pulmonary volume and attenuation: preinterventional and postinterventional computed tomography-quantification using separate lobe measurements.

OBJECTIVE: The aim of this study was to objectify changes in volume and density of treated and untreated pulmonary lobes following endobronchial coiling for lung volume reduction by comparison with clinical (6-m walk test) and pulmonary function tests. METHODS: Twenty-two lobes in 17 patients (8 men, 9 women) were treated by endobronchial coiling and underwent preinterventional and postinterventional computed tomography examinations (inspiratory and expiratory phase) as well as pulmonary function test measurements. RESULTS: Responders (n = 14) presented a significant increase (70 ± 11 m) in the walking distance (6-m walk test) and FEV1 (forced expiratory volume in 1 second) values (61 ± 21 mL). Only in responders inspiratory volume (VolIn) of the target lobe significantly decreased (10.0% ± 16.4%; P = 0.0245), and VolIn of the nontreated ipsilateral lobe significantly increased (5.5% ± 9.1%; P = 0.0209). CONCLUSIONS: Our results objectify volume reduction of the treated lobe coupled by a significant volume expansion of the ipsilateral lobe as a sole correlate for clinical improvement in responders.

Dynamic Radial MR Imaging for Endoleak Surveillance after Endovascular Repair of Abdominal Aortic Aneurysms with Inconclusive CT Angiography: A Prospective Study.

Background/Objectives: To assess free-breathing, dynamic radial magnetic resonance angiography (MRA) for detecting endoleaks post-endovascular aortic repair (EVAR) in cases with inconclusive computed tomography angiography (CTA). Methods: This prospective single-center study included 17 participants (mean age, 70 ± 9 years; 13 males) who underwent dynamic radial MRI (Golden-angle RAdial Sparse Parallel-Volumetric Interpolated BrEath-hold, GRASP-VIBE) after inconclusive multiphasic CT for the presence of endoleaks during the follow-up of EVAR-treated abdominal aortic aneurysms. CT and MRI datasets were independently assessed by two radiologists for image quality, diagnostic confidence, and the presence/type of endoleak. Statistical analyses included interrater and intermethod agreement, and diagnostic performance (sensitivity, specificity, area under the curve (AUC)). Results: Subjective image analysis demonstrated good image quality and interrater agreement (k ≥ 0.6) for both modalities, while diagnostic confidence was significantly higher in MRA (p = 0.03). There was significantly improved accuracy for detecting type II endoleaks on MRA (AUC 0.97 [95% CI: 0.87, 1.0]) compared to CTA (AUC 0.66 [95% CI: 0.41, 0.91]; p = 0.03). Although MRA demonstrated higher values for sensitivity, specificity, AUC, and interrater agreement, none of the other types nor the overall detection rate for endoleaks showed differences in the diagnostic performance over CT (p ≥ 0.12). CTA and MRA revealed slight to moderate intermethod concordance in endoleak detection (k = 0.3-0.64). Conclusions: The GRASP-VIBE MRA characterized by high spatial and temporal resolution demonstrates clinical feasibility with good image quality and superior diagnostic confidence. It notably enhances diagnostic performance in detecting and classifying endoleaks, particularly type II, compared to traditional multiphase CTA with inconclusive findings.

Ultrashort echo time MR imaging with off-resonance saturation for characterization of pathologically altered Achilles tendons at 3 T.

Off-resonance radiofrequency saturation pulses applied prior to regular excitation in MR sequences can be used to modify signal contrast based on magnetization transfer and direct saturation effects. Clinical applicability and value of ultrashort echo time sequences combined with off-resonance saturation pulses was tested in 16 healthy and 14 tendinopathic as well as paratendinopathic Achilles tendons in vivo at 3 T. A 3D ultrashort echo time sequence in combination with a gaussian off-resonance saturation pulse (frequency offset: 1000-5000 Hz) was used to modify the detectable MR signal intensity from the Achilles tendon. Off-resonance saturation ratio was calculated as the relative reduction in signal intensity under selective off-resonance saturation in relation to a reference measurement without any saturation pulse. Off-resonance saturation ratio in tendons of healthy volunteers ranged from 0.52 ± 0.06 (1000 Hz) to 0.24 ± 0.02 (5000 Hz), whereas symptomatic tendinopathic tendons (0.35 ± 0.04 to 0.17 ± 0.02) and asymptomatic tendinopathic tendons (0.41 ± 0.06 to 0.21 ± 0.02) showed significantly lower mean off-resonance saturation ratio values. Off-resonance saturation ratio values might provide a sensitive and quantitative marker for assessment of pathological microstructure alterations of the Achilles tendon.

Magnetic resonance imaging of solid dental restoration materials using 3D UTE sequences: visualization and relaxometry of various compounds.

OBJECT: Due to an increasing scientific interest in MR-imaging of carious lesions and teeth, an accurate signal characterization of dental restoration materials is necessary for optimization of MR sequence protocols and evaluation of material degradation. Therefore, signal yield and relaxation behavior of common dental restoration materials in comparison to those of dentine of extracted human teeth were assessed in vitro by ultrashort echo time (UTE) sequences. MATERIALS AND METHODS: Eighteen material samples and dentine of two freshly extracted human teeth were investigated on a 3T whole-body clinical MR-scanner. Transverse (T2*) and longitudinal relaxation times (T1) were quantified using a recently published modified Ernst equation that takes relevant in-pulse relaxation effects into account. RESULTS: All investigated samples could be successfully visualized but maximum signal yield was highly variable between samples. T1-values of the investigated dental restoration materials ranged between 28 and 365 ms, whereas T2*-values ranged between 96 and 917 µs. In contrast, T1-values of dentine (T1=545 ms±299 ms) were higher, while T2*-values (T2*=478 µs±271 µs) showed similar values. CONCLUSIONS: Dental restoration materials and dentine of extracted human teeth can be visualized by UTE sequences and show a broad range of signal yield and relaxation times.