Accelerating Cardiac Diffusion Tensor Imaging With a U-Net Based Model: Toward Single Breath-Hold.

BACKGROUND: In vivo cardiac diffusion tensor imaging (cDTI) characterizes myocardial microstructure. Despite its potential clinical impact, considerable technical challenges exist due to the inherent low signal-to-noise ratio. PURPOSE: To reduce scan time toward one breath-hold by reconstructing diffusion tensors for in vivo cDTI with a fitting-free deep learning approach. STUDY TYPE: Retrospective. POPULATION: A total of 197 healthy controls, 547 cardiac patients. FIELD STRENGTH/SEQUENCE: A 3 T, diffusion-weighted stimulated echo acquisition mode single-shot echo-planar imaging sequence. ASSESSMENT: A U-Net was trained to reconstruct the diffusion tensor elements of the reference results from reduced datasets that could be acquired in 5, 3 or 1 breath-hold(s) (BH) per slice. Fractional anisotropy (FA), mean diffusivity (MD), helix angle (HA), and sheetlet angle (E2A) were calculated and compared to the same measures when using a conventional linear-least-square (LLS) tensor fit with the same reduced datasets. A conventional LLS tensor fit with all available data (12 ± 2.0 [mean ± sd] breath-holds) was used as the reference baseline. STATISTICAL TESTS: Wilcoxon signed rank/rank sum and Kruskal-Wallis tests. Statistical significance threshold was set at P = 0.05. Intersubject measures are quoted as median [interquartile range]. RESULTS: For global mean or median results, both the LLS and U-Net methods with reduced datasets present a bias for some of the results. For both LLS and U-Net, there is a small but significant difference from the reference results except for LLS: MD 5BH (P = 0.38) and MD 3BH (P = 0.09). When considering direct pixel-wise errors the U-Net model outperformed significantly the LLS tensor fit for reduced datasets that can be acquired in three or just one breath-hold for all parameters. DATA CONCLUSION: Diffusion tensor prediction with a trained U-Net is a promising approach to minimize the number of breath-holds needed in clinical cDTI studies. EVIDENCE LEVEL: 4 TECHNICAL EFFICACY: Stage 1.

Barriers to medication adherence in the emergency department: A cross-sectional study.

BACKGROUND: Medication nonadherence is a common problem that leads to increased healthcare utilization. It is unclear how patient insight and attitude towards their medications affect adherence in the ED. Furthermore, it is unclear how perceived medication importance differs between patients and ED physicians. METHODS: We conducted a cross sectional study of adult patients presenting to 2 academic emergency departments from April 2015 to October 2016. Demographic data were collected and questions were asked regarding medication knowledge, perceived importance, and adherence. We also compared perceived importance of medications between patients and two physician raters. Inter-rater agreement was reported as raw percentages, and categorical data were compared using chi-squared analysis. RESULTS: We identified 1268 patients, representing 4634 individual medications. We identified a significant association between knowledge of medications and perceived importance (p < .05). Secondarily, importance level was highly associated with medication adherence (p < .05). When ranking those medications that were considered "least" and "most" important among each patient's med list, our two physicians agreed with patients only 34.1% and 37% of the time respectively, as opposed to 62% and 62.8% agreement between each other. CONCLUSIONS: These data suggest that there is a difference in perceived medication importance between ED physicians and ED patients. Knowledge of a medication's purpose is significantly associated with perceived importance, while this importance appears to be significantly associated with compliance. These results suggest that concerted efforts by ED physicians and staff to educate patients on the utility and importance of their medications may improve adherence.

Pelvic Blood Flow Predicts Fibroid Volume and Embolic Required for Uterine Fibroid Embolization: A Pilot Study With 4D Flow MR Angiography.

OBJECTIVE: We report here an initial experience using 4D flow MRI in pelvic imaging-specifically, in imaging uterine fibroids. We hypothesized that blood flow might correlate with fibroid volume and that quantifying blood flow might help to predict the amount of embolic required to achieve stasis at subsequent uterine fibroid embolization (UFE). MATERIALS AND METHODS: Thirty-three patients with uterine fibroids and seven control subjects underwent pelvic MRI with 4D flow imaging. Of the patients with fibroids, 10 underwent 4D flow imaging before UFE and seven after UFE; in the remaining 16 patients with fibroids, UFE had yet to be performed. Four-dimensional flow measurements were performed using Arterys CV Flow. The flow fraction of the internal iliac artery was expressed as the ratio of internal iliac artery flow to external iliac artery flow and was compared between groups. The flow ratios between the internal iliac arteries on each side were calculated. Fibroid volume versus internal iliac flow fraction, embolic volume versus internal iliac flow fraction, and embolic volume ratio between sides versus the ratio of internal iliac artery flows between sides were compared. RESULTS: The mean internal iliac flow fraction was significantly higher in the 26 patients who underwent imaging before UFE (mean ± standard error, 0.78 ± 0.06) than in the seven patients who underwent imaging after UFE (0.48 ± 0.07, p < 0.01) and in the seven control patients without fibroids (0.48 ± 0.08, p < 0.0001). The internal iliac flow fraction correlated well with fibroid volumes before UFE (r = 0.7754, p < 0.0001) and did not correlate with fibroid volumes after UFE (r = -0.3051, p = 0.51). The ratio of embolic required to achieve stasis between sides showed a modest correlation with the ratio of internal iliac flow (r = 0.6776, p = 0.03). CONCLUSION: Internal iliac flow measured by 4D flow MRI correlates with fibroid volume and is predictive of the ratio of embolic required to achieve stasis on each side at subsequent UFE and may be useful for preprocedural evaluation of patients with uterine fibroids.

Technical and Anatomic Factors Influencing the Success of Inferior Vena Caval Stent Placement for Malignant Obstruction.

PURPOSE: To evaluate the outcomes of inferior vena cava (IVC) stent placement for malignant obstruction and to identify anatomic and procedural factors influencing technical and clinical success. MATERIALS AND METHODS: A total of 57 patients (37 male, 20 female; age range, 22-86 y) underwent 62 IVC stent placement procedures using 97 stents (47 Wallstents, 15 S.M.A.R.T. stents, 18 Wallflex stents, 17 others) from 2005 to 2016 for malignant IVC obstruction caused by hepatic metastases (n = 22; 39%), primary hepatic malignancy (n = 16; 28%), retroperitoneal metastases (n = 16; 28%), or other primary malignancy (n = 5; 9%). Presenting symptoms included lower-extremity edema (n = 54; 95%), ascites (n = 28; 50%), and perineal edema (n = 14; 25%). Sixteen percent (n = 10) and 10% (n = 6) of the procedures involved tumor and bland thrombus, respectively. RESULTS: Stent placements resulted in 100% venographic patency and significantly decreased pressure gradients (P < .0001). Lower-extremity swelling, perineal swelling, and abdominal distension improved within 7 days in 83% (35 of 42), 100% (9 of 9), and 40% (6 of 15) of patients, respectively, and at 30 days after the procedure in 86% (25 of 29), 89% (8 of 9), and 80% (4 of 5) of patients, respectively. Increased pre- and post-stent placement pressure gradients were associated with worse outcomes. A 4% stent misplacement rate (4 of 97) was related to the use of Wallstents with caudal stent tapering, asymmetric deployment superior to the obstruction, suprahepatic IVC involvement, and decreased stent adherence to the IVC wall as a result of local mechanical factors. CONCLUSIONS: Stent placement is reliable, rapid, and durable in improving malignant IVC syndrome. Understanding of technical and anatomic factors can improve accuracy and avoid complications of stent misplacement.

Fusion dual-tracer SPECT-based hepatic dosimetry predicts outcome after radioembolization for a wide range of tumour cell types.

PURPOSE: Fusion dual-tracer SPECT imaging enables physiological rather than morphological voxel-based partitioning and dosimetry for (90)Y hepatic radioembolization (RE). We evaluated its prognostic value in a large heterogeneous cohort of patients with extensive hepatic malignancy. METHODS: A total of 122 patients with primary or secondary liver malignancy (18 different cell types) underwent SPECT imaging after intraarterial injection of (99m)Tc macroaggregated albumin (TcMAA) as a simulation of subsequent (90)Y microsphere distribution, followed by administration of an excess of intravenous (99m)Tc-labelled sulphur colloid (TcSC) as a biomarker for functional liver, and a second SPECT scan. TcMAA distribution was used to estimate (90)Y radiation absorbed dose in tumour (D T) and in functional liver. Laboratory and clinical follow-up were recorded for 12 weeks after RE, and radiographic responses according to (m)RECIST were evaluated at 3 and 6 months. Dose-response relationships were determined for efficacy and toxicity. RESULTS: Patients were treated with a median of 1.73 GBq activity of resin microspheres (98 patients) or glass microspheres (24 patients), in a whole-liver approach (97 patients) or a lobar approach (25 patients). The objective response rate was 41% at 3 months and 48% at 6 months. Response was correlated with D T (P < 0.01). Median overall survival was 10.1 months (95% confidence interval 7.4 - 12.8 months). Responders lived for 36.0 months compared to 8.7 months for nonresponders (P < 0.01). Stratified for tumour cell type, D T was independently associated with survival (P < 0.01). Absorbed dose in functional liver was correlated with toxicity grade change (P < 0.05) and RE-induced liver disease (P < 0.05). CONCLUSION: Fusion dual-tracer SPECT imaging offers a physiology-based functional imaging tool to predict efficacy and toxicity of RE. This technique can be refined to define dosing thresholds for specific tumour types and treatments, but appears generally predictive even in a heterogeneous cohort.

Scrub Typhus and Dengue Co-infection in an Adolescent Girl: A Diagnostic Challenge.

Scrub typhus and dengue fever are common infectious diseases in tropical regions, and both have overlapping clinico-epidemiological and laboratory features, which often pose a diagnostic challenge. This case report discusses a 15-year-old girl from the Indian subcontinent who presented with acute undifferentiated febrile illness (AUFI) without typical features of any of the common tropical infections. She was diagnosed with co-infection of scrub typhus and dengue fever using laboratory tests with good diagnostic accuracy. The patient was managed on an ambulatory basis, treated with oral doxycycline, and showed symptomatic improvement within 48 hours. Co-infections in endemic areas present a significant diagnostic and therapeutic challenge. This case report highlights the importance of considering co-infections in the differential diagnosis of AUFI, especially during the post-monsoon period, and the use of highly sensitive and specific tests for the diagnosis of co-infections.

Pulmonary Embolism Response to Fragmentation, Embolectomy, and Catheter Thrombolysis (PERFECT): Initial Results From a Prospective Multicenter Registry.

BACKGROUND: Systemic thrombolysis for acute pulmonary embolism (PE) carries up to a 20% risk of major bleeding, including a 2% to 5% risk of hemorrhagic stroke. We evaluated the safety and effectiveness of catheter-directed therapy (CDT) as an alternative treatment of acute PE. METHODS: One hundred one consecutive patients receiving CDT for acute PE were prospectively enrolled in a multicenter registry. Massive PE (n = 28) and submassive PE (n = 73) were treated with immediate catheter-directed mechanical or pharmacomechanical thrombectomy and/or catheter-directed thrombolysis through low-dose hourly drug infusion with tissue plasminogen activator (tPA) or urokinase. Clinical success was defined as meeting all the following criteria: stabilization of hemodynamics; improvement in pulmonary hypertension, right-sided heart strain, or both; and survival to hospital discharge. Primary safety outcomes were major procedure-related complications and major bleeding events. RESULTS: Fifty-three men and 48 women (average age, 60 years [range, 22-86 years]; mean BMI, 31.03 ± 7.20 kg/m2) were included in the study. The average thrombolytic doses were 28.0 ± 11 mg tPA (n = 76) and 2,697,101 ± 936,287 International Units for urokinase (n = 23). Clinical success was achieved in 24 of 28 patients with massive PE (85.7%; 95% CI, 67.3%-96.0%) and 71 of 73 patients with submassive PE (97.3%; 95% CI, 90.5%-99.7%). The mean pulmonary artery pressure improved from 51.17 ± 14.06 to 37.23 ± 15.81 mm Hg (n = 92) (P < .0001). Among patients monitored with follow-up echocardiography, 57 of 64 (89.1%; 95% CI, 78.8%-95.5%; P < .0001) showed improvement in right-sided heart strain. There were no major procedure-related complications, major hemorrhages, or hemorrhagic strokes. CONCLUSIONS: CDT improves clinical outcomes in patients with acute PE while minimizing the risk of major bleeding. At experienced centers, CDT is a safe and effective treatment of both acute massive and submassive PE. TRIAL REGISTRY: ClinicalTrials.gov; No.: NCT01097928; URL: www.clinicaltrials.gov.

Splenomegaly-associated thrombocytopenia after hepatic yttrium-90 radioembolization.

PURPOSE: Thrombocytopenia is often observed after yttrium-90 radioembolization (RE). Possible mechanisms include radiation toxicity to the bone marrow, consumption in the liver due to local radiation effects, and sequestration in the spleen. We sought to identify the causative factors. MATERIALS AND METHODS: Patients with complete baseline and 3-month post-RE imaging and laboratory data were included in this retrospective analysis. Univariate and multivariate regression analyses were performed on clinical, procedural, and imaging data. RESULTS: A total of 116 patients were identified (65 male, 51 female; median age 64 years). Forty-six patients were treated for primary and 70 for metastatic liver malignancy. Of these, 86 were treated with resin and 30 with glass microspheres; median activity was 1.85 GBq. Eighty-three patients underwent whole-liver treatment. Maximum individual change in platelet count was -20.2 % leading to new or increased grade of thrombocytopenia in 48 patients (41.4 %) by National Cancer Institute Common Toxicity Criteria for Adverse Events version 4.02 criteria. Independent risk factors for decreased platelet count included change in spleen volume (median change +17.5 %; p = 0.001) and whole-liver (rather than lobar or segmental) treatment (p = 0.025). Administered activity and absorbed dose were not associated with change in platelet count. The change in spleen volume itself was associated with previous epidermal growth factor receptor-inhibitor treatment (p = 0.002), whole-liver absorbed dose (p = 0.027), and multiple-line chemotherapy (0.012) for whole-liver treatments only. CONCLUSION: Post-RE treatment increase of spleen volume is correlated with decreased peripheral platelet count suggesting a mechanism of increased portal hypertension and hypersplenism being responsible.

The efficacy of hepatic 90Y resin radioembolization for metastatic neuroendocrine tumors: a meta-analysis.

UNLABELLED: (90)Y resin radioembolization is an emerging treatment in patients with liver-dominant metastatic neuroendocrine tumors (mNETs), despite the absence of level I data. The aim of this study was to evaluate the efficacy of this modality in a meta-analysis of the published literature. METHODS: A comprehensive review protocol screened all reports in the literature. Strict selection criteria were applied to ensure consistency among the selected studies: human subjects, complete response data with time interval, resin microspheres, more than 5 patients, not a duplicate cohort, English language, and separate and complete data for resin-based (90)Y treatment of mNET if the study included multiple tumor and microsphere types. Selected studies were critically appraised on 50 study criteria, in accordance with the research reporting standards for radioembolization. Response data (Response Evaluation Criteria in Solid Tumors) were extracted and analyzed using both fixed and random-effects meta-analyses. RESULTS: One hundred fifty-six studies were screened; 12 were selected, totaling 435 procedures for response assessment. Funnel plots showed no evidence of publication bias (P = 0.841). Critical appraisal revealed a median of 75% of desired criteria included in selected studies. Very high between-study heterogeneity ruled out a fixed-effects model. The random-effects weighted average objective response rate (complete and partial responses, CR and PR, respectively) was 50% (95% confidence interval, 38%-62%), and weighted average disease control rate (CR, PR, and stable disease) was 86% (95% confidence interval, 78%-92%). The percentage of patients with pancreatic mNET was marginally associated with poorer response (P = 0.030), accounting for approximately 23% of the heterogeneity among studies. The percentage of CR and PR correlated with median survival (R = 0.85; P = 0.008). CONCLUSION: This meta-analysis confirms radioembolization to be an effective treatment option for patients with hepatic mNET. The pooled data demonstrated a high response rate and improved survival for patients responding to therapy.