Percutaneous treatment of symptomatic deep vein thrombosis in adolescents using large-bore thrombectomy systems.

BACKGROUND: While large-bore mechanical thrombectomy provides effective venous thrombus removal, often with avoidance of thrombolytics, literature surrounding the application of these devices in pediatric patients is sparse. OBJECTIVE: To report technical success and outcomes following large-bore thrombectomy systems in adolescent patients with deep venous thrombosis. MATERIALS AND METHODS: A retrospective review identified all patients less than 18 years of age undergoing mechanical venous thrombectomy at a single institution between 2018 and 2022. No patients were excluded. Technical success was defined as extraction of thrombus sufficient to restore unimpeded flow in affected segments. Clinical success was defined as resolution of presenting symptoms. RESULTS: Nine consecutive patients (6 females, 3 males; age range 15-17 years) underwent 10 thrombectomy procedures using ClotTriever (n=6; 60%), FlowTriever (n=2; 20%), or both (n=2; 20%). Chronicity of thrombus was categorized as acute (<2 weeks) in 6 (60%), subacute (2-6 weeks) in 1 (10%), and chronic (>6 weeks) in 3 (30%). Distribution of thrombus was lower extremity and/or inferior vena cava (IVC) in 9 (90%) and unilateral axillo-subclavian in 1 (10%). Technical success was achieved in 9 interventions (90%). Clinical success was achieved in 8 patients (88.9%). No patients received thrombolytics. There were no intraprocedural adverse events (AE). Minor complications (Society of Interventional Radiology mild adverse events) were observed in a delayed fashion following 2 interventions (20%). CONCLUSIONS: This preliminary experience demonstrated high rates of technical and clinical success with large-bore deep venous thrombectomy in adolescent patients across a range of thrombus chronicity and locations.

Intravascular US: Applications in Interventional Radiology.

Interventional radiology applications of intravascular US (IVUS) continue to expand, complementing intraprocedural angiography and providing a unique vantage from which to guide endovascular interventions. Vascular pathologic conditions become sonographically visualized rather than inferred from the planar appearance of the opacified vascular lumen. Perivascular targets become sonographically visualized rather than approximated on the basis of fluoroscopic landmarks. The authors introduce broad categories of IVUS catheters, namely radial and side-firing varieties, as well as prevailing options for each and their technical specifications. Common applications within interventional radiology are covered in a systems approach, including deep venous thrombosis, May-Thurner syndrome, nutcracker syndrome, transjugular intrahepatic portosystemic shunts, aortic interventions, peripheral arterial disease, and endovascular or perivascular biopsy. Discussions are accompanied by technical pearls from the authors, and summarized evidence where IVUS has been shown to reduce procedural time, intravascular contrast agent dose, radiation exposure, and morbidity in each space is presented. Finally, emerging applications and future directions are discussed. ©RSNA, 2022.

Combined ultrasound and fluoroscopy guided tunneled external lumbar drain placement in children.

External lumbar drain placement has been shown to be an efficacious and safe approach to managing various forms of intracranial hypertension in adult patients and children. The use of ultrasound guidance for lumbar punctures in young patients has been described however, but the modality is not routinely used for the placement of tunneled lumbar drains. In this report, two cases are presented that detail experience using ultrasound guidance for tunneled lumbar drains in children.

Longitudinal Monitoring of Hepatic Blood Flow before and after TIPS by Using 4D-Flow MR Imaging.

Purpose To demonstrate the feasibility of four-dimensional (4D)-flow magnetic resonance (MR) imaging for noninvasive longitudinal hemodynamic monitoring of hepatic blood flow before and after transjugular intrahepatic portosystemic shunt (TIPS) placement. Materials and Methods The institutional review board approved this prospective Health Insurance Portability and Accountability Act compliant study with written informed consent. Four-dimensional-flow MR imaging was performed in seven patients with portal hypertension and refractory ascites before and 2 and 12 weeks after TIPS placement by using a time-resolved three-dimensional radial phase-contrast acquisition. Flow and peak velocity measurements were obtained in the superior mesenteric vein (SMV), splenic vein (SV), portal vein (PV), and the TIPS. Flow volumes and peak velocities in each vessel, as well as the ratio of in-stent to PV flow, were compared before and after TIPS placement by using analysis of variance. Results Flow volumes significantly increased in the SMV (0.24 L/min; 95% confidence interval [CI]: 0.07, 0.41), SV (0.31 L/min; 95% CI: 0.07, 0.54), and PV (0.88 L/min; 95% CI: 0.06, 1.70) after TIPS placement (all P < .05), with no significant difference between the first and second post-TIPS placement acquisitions (all P > .11). Ascites resolved in six of seven patients. In those with resolved ascites, the TIPS-to-PV flow ratio was 0.8 ± 0.2 and 0.9 ± 0.2 at the two post-TIPS time points, respectively, while the observed ratios were 4.6 and 4.3 in the patient with refractory ascites at the two post-TIPS time points, respectively. In this patient, 4D-flow MR imaging demonstrated arterio-portal-venous shunting, with draining into the TIPS. Conclusion Four-dimensional-flow MR imaging is feasible for noninvasive longitudinal hemodynamic monitoring of hepatic blood flow before and after TIPS placement. © RSNA, 2016 Online supplemental material is available for this article.

Complex Inferior Vena Cava Filter Retrieval Complicated by Migration of Filter Fragment into the Aorta and Subsequent Distal Embolization.

In 2005, a 48-year-old man with a spinal cord injury had an inferior vena cava filter placed for recurrent deep vein thrombosis and pulmonary embolism. He was referred for filter retrieval after a computed tomography scan demonstrated caval stenosis and 2 fractured filter arms, 1 in a pulmonary artery and 1 penetrating into the retroperitoneum and impinging on the aorta. During retrieval, 1 arm was inadvertently advanced into the aorta, and embolization of the arm occurred to the left profunda femoris artery. It was subsequently retrieved. This is the first reported case to the authors' knowledge of migration and embolization of a filter fragment into the systemic arterial system.

Correlation of Imaging and Hemodynamic Findings with Clinical Outcomes for Diagnosis of Left Renal Vein Compression Syndrome.

PURPOSE: Left renal vein compression syndrome (LRVCS) remains a challenging diagnosis. This study aimed to correlate imaging and hemodynamic findings with clinical outcomes for patients with LRVCS. MATERIALS AND METHODS: A retrospective review of 66 renal venography procedures with or without intravascular ultrasound (IVUS) was performed from 2017 to 2023 at a single institution. Patients with prior LRVCS treatment or other indications were excluded (n = 11). Primary outcome measure was correlation of catheter-based endovascular (CBE) findings with clinical outcomes (n = 55). Secondary outcome measures included correlation of CBE findings and LRV (i.e., beak) angle > 32°, beak sign, aortomesenteric angle (AMA < 41°), and hilar-to-aortomesenteric ratio (HTAMR ≥ 4.9) on cross sectional imaging. Descriptive statistics, chi-square testing, and ROC analyses were used. RESULTS: Of the 55 patients, 52 (94.5%) were females (median age 31, range 14-72) and 56.4% (n = 31) had a diagnosis of LRVCS on CBE evaluation. A renocaval pressure gradient of ≥ 3 mmHg, presence of collaterals, and > 50% area stenosis on IVUS were significantly associated with CBE diagnosis of LRVCS (p < 0.001). Surgical treatment (renal autotransplantation or LRV transposition) was recommended to all patients with CBE diagnosis of LRVCS (n = 31). 81.2% (18/22) of patients who underwent surgery reported symptom resolution or improvement. When the cross sectional imaging measurements were compared with CBE evaluation, AMA was the most sensitive (100%), HTAMR and beak sign were highly specific (93.3%), and beak angle was the most predictive (77.4% sensitivity; 86.7% specificity). CONCLUSION: CBE diagnosis of LRVCS was highly predictive of surgical candidacy and post-surgical symptom resolution. The presence of collaterals, > 50% area stenosis on IVUS, or a renocaval pressure gradient ≥ 3 mmHg had a significant association with a CBE diagnosis of LRVCS.

Evaluation of the menisci of the knee joint using three-dimensional isotropic resolution fast spin-echo imaging: diagnostic performance in 250 patients with surgical correlation.

OBJECTIVE: To compare the diagnostic performance of FSE-Cube, a three-dimensional isotropic resolution intermediate-weighted fast spin-echo sequence, with a routine magnetic resonance (MR) protocol at 3.0 T for detecting surgically confirmed meniscal tears of the knee joint in a large patient population. METHODS: FSE-Cube was added to a routine MR protocol performed at 3.0 T on 250 patients who underwent subsequent knee arthroscopy. Three radiologists independently used FSE-Cube during one review and the routine MR protocol during a second review to detect medial and lateral meniscal tears. Using arthroscopy as the reference standard, the sensitivity and specificity of FSE-Cube and the routine MR protocol for detecting meniscal tears were determined for all readers combined. McNemar's tests were used to compare diagnostic performance between FSE-Cube and the routine MR protocol. RESULTS: FSE-Cube and the routine MR protocol had similar sensitivity (95.5%/95.3% respectively, P = 0.94) and similar specificity (69.8%/74.0% respectively, P = 0.10) for detecting 156 medial meniscal tears. FSE-Cube had significantly lower sensitivity than the routine MR protocol (79.4%/85.0% respectively, P < 0.05) but similar specificity (83.9%/82.2% respectively, P = 0.37) for detecting 89 lateral mensical tears. For lateral meniscal tears, FSE-Cube had significantly lower sensitivity (P < 0.05) than the routine MR protocol for detecting 19 root tears but similar sensitivity (P = 0.17-1.00) for detecting all other tear locations and types. CONCLUSION: FSE-Cube had diagnostic performance similar to a routine MR protocol for detecting meniscal tears except for a significantly lower sensitivity for detecting lateral meniscal tears, which was mainly attributed to decreased ability to identify lateral meniscus root tears.

Arthroscopic partial meniscectomy: MR imaging for prediction of outcome in middle-aged and elderly patients.

PURPOSE: To determine whether preoperative magnetic resonance (MR) imaging could help identify factors associated with poor clinical outcome after arthroscopic partial meniscectomy (APM) in middle-aged and elderly patients with meniscal tears. MATERIALS AND METHODS: The prospective, institutional review board-approved, HIPAA-compliant study was performed with informed consent in 53 men and 47 women (average ages, 54.5 and 56.6 years, respectively). Patients underwent knee MR imaging before APM; clinical symptoms were evaluated preoperatively and 1 year postoperatively with International Knee Documentation Committee (IKDC) questionnaire. Overall severity of knee joint degeneration and severity of each feature of joint degeneration were assessed with Boston Leads Osteoarthritis Knee (BLOK) scoring system. Tear length was measured, and type of meniscal tear was classified. Spearman correlation coefficients and relative risks showed the relationship between clinical outcome after APM (difference between preoperative and postoperative IKDC scores) and severity of joint degeneration. RESULTS: Seventy-four patients with isolated medial APM had a significant (P < .05) inverse correlation between clinical outcome and severity of cartilage loss and bone marrow edema in the medial femoral condyle and medial tibial plateau. Fifteen patients with isolated lateral APM had a significant (P < .05) inverse correlation between clinical outcome and severity of cartilage loss in the lateral femoral condyle and lateral tibial plateau and bone marrow edema in the lateral femoral condyle. One hundred patients with APM had a significant (P < .05) inverse correlation between clinical outcome and severity of meniscal extrusion, total BLOK score, and meniscal tear length. A significantly (P < .05) increased relative risk that a patient would not definitely improve after APM was observed if a meniscal root tear was present. CONCLUSION: Poorer clinical outcome after APM was associated with greater severity of cartilage loss and bone marrow edema in the same compartment as the meniscal tear, greater severity of meniscal extrusion, greater overall severity of joint degeneration, a meniscal root tear, and a longer meniscal tear at preoperative MR imaging.

3.0-T evaluation of knee cartilage by using three-dimensional IDEAL GRASS imaging: comparison with fast spin-echo imaging.

PURPOSE: To compare the diagnostic performance of iterative decomposition of water and fat with echo asymmetry and least-squares estimation (IDEAL) gradient-recalled acquisition in steady-state (GRASS) imaging with a routine magnetic resonance (MR) imaging protocol for evaluating knee cartilage at 3.0 T in patients by using arthroscopy as the reference standard. MATERIALS AND METHODS: This prospective Health Insurance Portability and Accountability Act-compliant study was performed with a waiver of informed consent from the institutional review board. IDEAL GRASS was added to routine 3.0-T knee MR protocol performed in 95 symptomatic patients (48 males, mean age, 34.5 years; 47 females, mean age, 35.5 years) who underwent subsequent arthroscopic surgery. Radiologists used the routine MR protocol during the first review and IDEAL GRASS during the second to grade each articular surface and to determine the presence of meniscal tears. By using arthroscopy as the reference standard, the sensitivity, specificity, and accuracy of both imaging methods for detecting cartilage lesions and meniscal tears were determined. RESULTS: By using the z test to compare parameters between methods, the respective sensitivity, specificity, and accuracy for detecting all 192 cartilage lesions were 68.5%, 92.6%, and 84.5% for IDEAL GRASS and 66.1%, 92.9%, and 83.9% for the routine MR protocol. There was no significant difference (P = .34-.83) in parameters between methods for detecting cartilage lesions. The respective parameters for detecting 50 medial meniscal tears were 85.0%, 91.1%, and 87.9% for IDEAL GRASS and 94.0%, 90.0%, and 92.1% for the routine MR protocol. The parameters for detecting 31 lateral meniscal tears were 58.0%, 90.6%, and 80.0% for IDEAL GRASS and 80.1%, 91.4%, and 87.9% for the routine MR protocol. The routine MR protocol had a significantly higher sensitivity for detecting medial meniscal tears (P = .04) and lateral meniscal tears (P = .01) and significantly higher accuracy for detecting lateral meniscal tears (P = .03) than IDEAL GRASS. CONCLUSION: IDEAL GRASS has similar diagnostic performance as routine MR protocol for evaluating the articular cartilage of the knee in clinical patients at 3.0 T but has significantly lower sensitivity and accuracy for detecting meniscal tears.

Knee joint: comprehensive assessment with 3D isotropic resolution fast spin-echo MR imaging--diagnostic performance compared with that of conventional MR imaging at 3.0 T.

PURPOSE: To determine whether a three-dimensional isotropic resolution fast spin-echo sequence (FSE-Cube) has similar diagnostic performance as a routine magnetic resonance (MR) imaging protocol for evaluating the cartilage, ligaments, menisci, and osseous structures of the knee joint in symptomatic patients at 3.0 T. MATERIALS AND METHODS: This prospective, HIPAA-compliant, institutional review board-approved study was performed with a waiver of informed consent. FSE-Cube was added to the routine 3.0-T MR imaging protocol performed in 100 symptomatic patients (54 male patients with a median age of 32 years and 46 female patients with a median age of 33 years) who subsequently underwent arthroscopic knee surgery. All MR imaging studies were independently reviewed twice by two musculoskeletal radiologists. During the first review, the routine MR imaging protocol was used to detect cartilage lesions, ligament tears, meniscal tears, and bone marrow edema lesions. During the second review, FSE-Cube with multiplanar reformations was used to detect these joint abnormalities. With arthroscopic results as the reference standard, the sensitivity and specificity of FSE-Cube and the routine MR imaging protocol in the detection of cartilage lesions, anterior cruciate ligament tears, and meniscal tears were calculated. Permutation tests were used to compare sensitivity and specificity values. RESULTS: FSE-Cube had significantly higher sensitivity (P = .039) but significantly lower specificity (P = .003) than the routine MR imaging protocol for detecting cartilage lesions. There were no significant differences (P = .183-.999) in sensitivity and specificity between FSE-Cube and the routine MR imaging protocol in the detection of anterior cruciate ligament tears, medial meniscal tears, or lateral meniscal tears. FSE-Cube depicted 96.2% of medial collateral ligament tears, 100% of lateral collateral ligament tears, and 85.3% of bone marrow edema lesions identified on images obtained with the routine MR imaging protocol. CONCLUSION: FSE-Cube has similar diagnostic performance as a routine MR imaging protocol for detecting cartilage lesions, cruciate ligament tears, collateral ligament tears, meniscal tears, and bone marrow edema lesions within the knee joint at 3.0 T.

The cost effectiveness and utility of a "quick MRI" for the evaluation of intra-abdominal abscess after acute appendicitis in the pediatric patient population.

INTRODUCTION: Contrast-enhanced CT remains the first-line imaging for evaluating postoperative abscess (POA) after appendicitis. Given concerns of ionizing radiation use in children, we began utilizing quick MRI to evaluate POA and summarize our findings in this study. MATERIALS AND METHODS: Children imaged with quick MRI from 2015 to 2017 were compared to children evaluated with CT from 2012 to 2014 using an age and weight matched case-control model. Radiation exposure, size and number of abscesses, length of exam, drain placement, and patient outcomes were compared. RESULTS: There was no difference in age or weight (p>0.60) between children evaluated with quick MRI (n=16) and CT (n=16). Mean imaging time was longer (18.2±8.5min) for MRI (p<0.001), but there was no difference in time from imaging order to drain placement (p=0.969). No children required sedation or had non-diagnostic imaging. There were no differences in abscess volume (p=0.346) or drain placement (p=0.332). Thirty-day follow-up showed no difference in readmissions (p=0.551) and no missed abscesses. Quick MRI reduced imaging charges to $1871 from $5650 with CT. CONCLUSION: Quick MRI demonstrated equivalent outcomes to CT in terms of POA detection, drain placement, and 30-day complications suggesting that MRI provides an equally effective, less expensive, and non-radiation modality for the identification of POA. TYPE OF STUDY: Retrospective Case-Control Study. LEVEL OF EVIDENCE: Level III.

Improved fat suppression using multipeak reconstruction for IDEAL chemical shift fat-water separation: application with fast spin echo imaging.

PURPOSE: To evaluate and quantify improvements in the quality of fat suppression for fast spin-echo imaging of the knee using multipeak fat spectral modeling and IDEAL fat-water separation. MATERIALS AND METHODS: T(1)-weighted and T(2)-weighted fast spin-echo sequences with IDEAL fat-water separation and two frequency-selective fat-saturation methods (fat-selective saturation and fat-selective partial inversion) were performed on 10 knees of five asymptomatic volunteers. The IDEAL images were reconstructed using a conventional single-peak method and precalibrated and self-calibrated multipeak methods that more accurately model the NMR spectrum of fat. The signal-to-noise ratio (SNR) was measured in various tissues for all sequences. Student t-tests were used to compare SNR values. RESULTS: Precalibrated and self-calibrated multipeak IDEAL had significantly greater suppression of signal (P < 0.05) within subcutaneous fat and bone marrow than fat-selective saturation, fat-selective partial inversion, and single-peak IDEAL for both T(1)-weighted and T(2)-weighted fast spin-echo sequences. For T(1)-weighted fast spin-echo sequences, the improvement in the suppression of signal within subcutaneous fat and bone marrow for multipeak IDEAL ranged between 65% when compared to fat-selective partial inversion to 86% when compared to fat-selectivesaturation. For T2-weighted fast spin-echo sequences, the improvement for multipeak IDEAL ranged between 21% when compared to fat-selective partial inversion to 81% when compared to fat-selective saturation. CONCLUSION: Multipeak IDEAL fat-water separation provides improved fat suppression for T(1)-weighted and T(2)-weighted fast spin-echo imaging of the knee when compared to single-peak IDEAL and two widely used frequency-selected fat-saturation methods.