Faculty Bibliography

PURPOSE/OBJECTIVE:Venous malformations (VMs) are low-flow vascular anomalies that are commonly treated with image-guided percutaneous sclerotherapy. Although many VMs can be safely accessed and treated using ultrasonography and fluoroscopy, some lesions may be better treated with magnetic resonance imaging (MRI)-guided sclerotherapy. The aim of this study is to evaluate the feasibility, efficiency, and outcomes of MRI-guided sclerotherapy of VMs using a 3T MRI system. METHODS:Six patients with VMs in the neck (n = 2), chest (n = 1), and extremities (n = 3) underwent sclerotherapy with 3T MRI guidance. Feasibility was assessed by calculating the technical success rate and procedural efficiency. Efficiency was evaluated by using planning, targeting, intervention, and total procedure times. Outcomes were assessed by measuring VM volumes before and after sclerotherapy, patient-reported pain scores, and occurrence of complications. RESULTS:Technical success was achieved in all 6 procedures. There was a non-significant 30% decrease in mean VM volume after the procedure (P = .350). The procedure resulted in a decrease in mean pain score (on an 11-point scale) of 2.6 points (P = .003). After the procedure, 4 patients reported complete pain resolution, 1 reported partial pain resolution, and 1 reported no change in pain. Procedural efficiency was consistent with similar sclerotherapy procedures performed at our institution. There were no major or minor complications. CONCLUSION/CONCLUSIONS:3T MRI guidance is feasible for percutaneous sclerotherapy of VMs, with promising initial technical success rates, procedural efficiency, and therapeutic outcomes without complications.

Identifying MRI-based radiomics features capable to assess response to systemic treatment in multiple myeloma (MM) patients. Retrospective analysis of whole-body MR-image data in 67 consecutive stage III MM patients (40 men; mean age, 60.4 years). Bone marrow involvement was evaluated using a standardized MR-imaging protocol consisting of T1w-, short-tau inversion recovery- (STIR-) and diffusion-weighted-imaging (DWI) sequences. Ninety-two radiomics features were evaluated, both in focally and diffusely involved bone marrow. Volumes of interest (VOI) were used. Response to treatment was classified according to International Myeloma Working Group (IMWG) criteria in complete response (CR), very-good and/or partial response (VGPR + PR), and non-response (stable disease (SD) and progressive disease (PD)). According to the IMWG-criteria, response categories were CR (n = 35), VGPR + PR (n = 19), and non-responders (n = 13). On apparent diffusion coefficient (ADC)-maps, gray-level small size matrix small area emphasis (Gray Level Size Zone (GLSZM) small area emphasis (SAE)) significantly correlated with CR (p < 0.001), whereas GLSZM non-uniformity normalized (NUN) significantly (p < 0.008) with VGPR/PR in focal medullary lesions (FL), whereas in diffuse involvement, 1st order root mean squared significantly (p < 0.001) correlated with CR, whereas for VGPR/PR Log (gray-level run-length matrix (GLRLM) Short Run High Gray Level Emphasis) proved significant (p < 0.003). On T1w, GLRLM NUN significantly (p < 0.002) correlated with CR in FL, whereas gray-level co-occurrence matric (GLCM) informational measure of correlation (Imc1) significantly (p < 0.04) correlated with VGPR/PR. For diffuse myeloma involvement, neighboring gray-tone difference matrix (NGTDM) contrast and 1st order skewness were significantly associated with CR and VGPR/PR (p < 0.001 for both). On STIR-images, CR correlated with gray-level co-occurrence matrix (GLCM) Informational Measure of Correlation (IMC) 1 (p < 0.001) in FL and 1st order mean absolute deviation in diffusely involved bone marrow (p < 0.001). VGPR/PR correlated at best in FL with GSZLM size zone NUN (p < 0.019) and in all other involved medullary areas with GLSZM large area low gray level emphasis (p < 0.001). GLSZM large area low gray level emphasis also significantly correlated with the degree of bone marrow infiltration assessed histologically (p = 0.006). GLCM IMC 1 proved significant throughout T1w/STIR sequences, whereas GLSZM NUN in STIR and ADC. MRI-based texture features proved significant to assess clinical and hematological response (CR, VPGR, and PR) in multiple myeloma patients undergoing systemic treatment.

The majority of peripheral musculoskeletal soft tissue masses encountered in routine clinical practice are benign and associated with an excellent prognosis, whereas a small proportion of soft tissue masses are malignant and are associated with higher morbidity and mortality. Owing to the excellent tissue contrast resolution provided, magnetic resonance imaging (MRI) is a primary modality for the diagnostic evaluation of soft tissue masses, particularly for defining the anatomic extent. MRI is also useful for the characterization of soft tissue masses; however, after the exclusion of cysts and lipomas, it is challenging to accurately categorize neoplastic lesions as benign or malignant with conventional anatomic MRI. Quantitative MRI biomarkers obtained with nonconventional pulse sequences are becoming increasingly available, and can improve the accuracy of determining the character of soft tissue masses. In this article we discuss established qualitative and emerging quantitative MRI-based biomarkers available with dynamic contrast-enhanced MRI, diffusion-weighted imaging, and MR spectroscopy and their utility for the characterization of untreated soft tissue masses. Level of Evidence: 5 Technical Efficacy Stage: 5 J. Magn. Reson. Imaging 2019;50:11-27.

RATIONALE AND OBJECTIVES:This study aimed to test the hypothesis that ultrastructural wall abnormalities of lymphoma vessels correlate with perfusion computed tomography (PCT) kinetics. MATERIALS AND METHODS:), and electron microscopy was used to determine the presence or absence of tight junctions, endothelial fenestration, basement membrane, and pericytes, and to measure extracellular matrix thickness. RESULTS:(P = .038, r = 0.695). CONCLUSION:k-Trans values of PCT do not correlate with ultrastructural microvessel features, whereas endothelial fenestrations correlate with increased intra-tumoral BVs.

OBJECTIVES/OBJECTIVE:We aimed to test the hypothesis that the spleen-to-liver-attenuation ratio on portal-venous enhancement phase CT images can identify diffuse splenic infiltration in subjects with lymphoma. METHODS:A database search yielded 70 subjects with malignant haematological diseases who underwent contrast-enhanced CT (CECT) between December 2010 and March 2018. Additionally, consecutive control subjects were evaluated. We compared the splenic volume, splenic attenuation, spleen-to-liver, spleen-to-aorta and spleen-to-musculature ratios on portal-venous phase CECT images, pre- to post-treatment and between the different lymphoma entities. The standard of reference for splenic involvement was normalisation of the spleen volume following chemotherapy or normalisation of FDG-uptake. RESULTS:; p < .001). Spleen-to-liver ratio significantly increased in lymphoma patients after therapy, inversely correlating with the decline in FDG-uptake (n=10) even in patients with normal-sized spleens (2/10), staying unchanged at follow-up. The outcome variables were not significantly different between the lymphoma subtypes. CONCLUSIONS:We suggest the additional use of spleen-to-liver attenuation ratio to splenic volume alone for detection of diffuse splenic infiltration in subjects with lymphoma. The course of spleen-to-liver attenuation ratio inversely correlated with that of FDG-uptake in a subgroup of patients working accurately in normal-sized diffusely involved spleens. KEY POINTS/CONCLUSIONS:• Involvement of the spleen is frequent in haematological malignancies and is important for staging and appropriate treatment. • Diffuse splenic infiltration often results in only homogeneous splenomegaly without a focal lesion, but even no or only minimal increase in splenic volume is possible. In these cases diagnosis of spleen involvement is a challenge for the radiologist. • Our data support the use of the spleen-to-liver attenuation ratio in addition to size measurements for the detection of diffuse splenic infiltration in subjects with lymphoma.

PURPOSE/OBJECTIVE:To investigate whether liver stiffness measured by acoustic radiation force impulse (ARFI) sonoelastography always correlates with the liver perfusion parameters quantified by perfusion CT in patients with known liver cirrhosis. METHODS:Sonoelastography and perfusion CT were performed in 50 patients (mean age 65.5; range 45-87 years) with liver cirrhosis, who were classified according to Child-Pugh into class A (30/50, 60%), B (17/50, 34%), and C (3/50, 6%). For standardized ARFI measurements in the left liver lobe at a depth of 4 cm, a convex 6-MHz probe was used. CT examinations were performed using 80 kV, 100 mAs, and 50 ml of iodinated contrast agent injected at 5 ml/s. Using standardized region-of-interest measurements, we quantified arterial, portal venous, and total liver perfusion. RESULTS:There was a significant linear correlation between tissue stiffness and arterial liver perfusion (p = 0.015), and also when limiting the analysis to patients with histology (p = 0.019). In addition, there was a positive correlation between the total blood supply (arterial + portal-venous liver perfusion) to the liver and tissue stiffness (p = 0.001; with histology, p = 0.027). Shear wave velocity increased with higher Child-Pugh stages (p = 0.013). CONCLUSION/CONCLUSIONS:The degree of tissue stiffness in cirrhotic livers correlates expectedly-even if only moderately-with the magnitude of arterial liver perfusion and total liver perfusion. As such, liver elastography remains the leading imaging tool in assessing liver fibrosis.

OBJECTIVES/OBJECTIVE:To test the hypothesis that MRI of the ankle with a 10-min 3D CAIPIRINHA SPACE TSE protocol is at least equivalent for the detection of painful conditions when compared to a 20-min 2D TSE standard of reference protocol. METHODS:Following institutional review board approval and informed consent, 70 symptomatic subjects underwent 3T MRI of the ankle. Six axial, sagittal and coronal intermediate-weighted (IW) and fat-saturated T2-weighted (T2FS) 2D TSE (total acquisition time, 20 min), and two sagittal isotropic IW and T2FS 3D CAIPIRINHA TSE (10 min) pulse sequence prototypes were obtained. Following randomization and anonymization, two musculoskeletal radiologists evaluated the 2D and 3D datasets independently. Descriptive statistics, inter-reader reliability, inter-method concordance, diagnostic definitiveness tests were applied. P-values < 0.05 were considered significant. RESULTS:Raters diagnosed 116 cartilage defects with 2D and 109 with 3D MRI, 35 ligament tears with 2D and 65 with 3D MRI, 18 tendon tears with 2D and 20 with 3D MRI, and 137 osseous abnormalities with 2D and 149 with 3D MRI. The inter-reader agreement was high for 2D (Kendall W, 0.925) and 3D MRI (W, 0.936) (p < 0.05), as was the inter-method concordance (W, 0.919). The diagnostic definitiveness of readers was higher for 3D MRI than 2D MRI in 10-27% of the time, while the reverse was true in 7-11% of the time (p < 0.01). CONCLUSIONS:The performance of 10-min 3D CAIPIRINHA SPACE MRI for the detection of painful ankle conditions is similar to that of a 20-min 2D TSE MRI reference standard. KEY POINTS/CONCLUSIONS:• CAIPIRINHA Acceleration facilitates isotropic 3D MRI of the Ankle in 10 min. • 10-min 3D CAIPIRINHA MRI and 20-min 2D TSE MRI have similar performance. • 3D CAIPIRINHA SPACE MRI afforded higher diagnostic definitiveness of readers.

BACKGROUND:Ten-minute MRI of the pediatric knee can add value through increased cost-effectiveness and decreased sedation needs but requires validation of its clinical efficacy. PURPOSE/OBJECTIVE:To determine the arthroscopy-based diagnostic accuracy and interreader reliability of 10-min 3D Controlled Aliasing In Parallel Imaging Results In Higher Acceleration (CAIPIRINHA) turbo spin echo (TSE) MRI with two isotropic pulse sequences for the diagnosis of internal derangement in children with painful knee conditions. STUDY TYPE/METHODS:Prospective. SUBJECTS/METHODS:Sixty children. FIELD STRENGTH/SEQUENCE/UNASSIGNED:3T, gradient echo-based scout with automatic anatomical landmark recognition and plane prescription, 3D CAIPIRINHA SPACE TSE. ASSESSMENT/RESULTS:Three fellowship-trained musculoskeletal radiologists evaluated the MRI studies independently and resolved discrepancies through consensus. Outcome variables included image quality, motion artifacts, meniscal abnormalities, anterior and posterior cruciate ligament tears, and cartilage lesions. Arthroscopic surgery served as the standard of reference, which was performed after 37 (range, 1-143) days post-MRI. STATISTICAL TESTS/UNASSIGNED:Diagnostic accuracy analysis of MRI with arthroscopic surgery as the standard of reference. Reliability analysis through calculation of interreader agreements with kappa statistics. RESULTS:All studies were suitable for diagnostic interpretation with good-to-very-good image quality ratings and little-to-no motion degradation ratings in the majority of cases. The sensitivities/specificities/accuracies of 3D CAIPIRINHA TSE MRI were 0.93/0.96/0.94 for 15/60 (25%) medial meniscal tears, 0.95/0.92/0.94 for 21/60 (35%) lateral meniscal tears, 0.83/1.00/0.92 for 6/60 (17%) discoid menisci, 1.00/0.98/0.99 for 16/60 (27%) anterior cruciate ligament tears, 1.0/1.0/1.0 for 2/60 (3%) posterior cruciate ligament tears, 1.00/1.00/1.00 for 5/60 (8%) osteochondritis dissecans lesions, 0.71/0.96/0.84 for 48 (13%) defects in 360 cartilage segments, and 0.85/0.97/0.91 overall. The interreader agreements were overall good-to-very-good (kappa, 0.72-1.00). DATA CONCLUSION/UNASSIGNED:The clinical use of 10-min 3D CAIPIRINHA TSE MRI of the knee in children with painful knee conditions yields an overall high arthroscopy-validated diagnostic accuracy of 91% and good-to-very good interreader reliability for the diagnosis of internal knee derangements. LEVEL OF EVIDENCE/METHODS:1 Technical Efficacy: Stage 6 J. Magn. Reson. Imaging 2019;49:e139-e151.