MR Fingerprinting for Contrast Agent-free and Quantitative Characterization of Focal Liver Lesions.

Purpose To evaluate the feasibility of liver MR fingerprinting (MRF) for quantitative characterization and diagnosis of focal liver lesions. Materials and Methods This single-site, prospective study included 89 participants (mean age, 62 years ± 15 [SD]; 45 women, 44 men) with various focal liver lesions who underwent MRI between October 2021 and August 2022. The participants underwent routine clinical MRI, non-contrast-enhanced liver MRF, and reference quantitative MRI with a 1.5-T MRI scanner. The bias and repeatability of the MRF measurements were assessed using linear regression, Bland-Altman plots, and coefficients of variation. The diagnostic capability of MRF-derived T1, T2, T2*, proton density fat fraction (PDFF), and a combination of these metrics to distinguish benign from malignant lesions was analyzed according to the area under the receiver operating characteristic curve (AUC). Results Liver MRF measurements showed moderate to high agreement with reference measurements (intraclass correlation = 0.94, 0.77, 0.45, and 0.61 for T1, T2, T2*, and PDFF, respectively), with underestimation of T2 values (mean bias in lesion = -0.5%, -29%, 5.8%, and -8.2% for T1, T2, T2*, and PDFF, respectively). The median coefficients of variation for repeatability of T1, T2, and T2* values were 2.5% (IQR, 3.6%), 3.1% (IQR, 5.6%), and 6.6% (IQR, 13.9%), respectively. After considering multicollinearity, a combination of MRF measurements showed a high diagnostic performance in differentiating benign from malignant lesions (AUC = 0.92 [95% CI: 0.86, 0.98]). Conclusion Liver MRF enabled the quantitative characterization of various focal liver lesions in a single breath-hold acquisition. Keywords: MR Imaging, Abdomen/GI, Liver, Imaging Sequences, Technical Aspects, Tissue Characterization, Technology Assessment, Diagnosis, Liver Lesions, MR Fingerprinting, Quantitative Characterization Supplemental material is available for this article. © RSNA, 2023.

Glymphatic system impairment in sleep disruption: diffusion tensor image analysis along the perivascular space (DTI-ALPS).

PURPOSE: This study aimed to evaluate the relationship between sleep quality as assessed using the Pittsburgh Sleep Quality Index (PSQI) and the index of diffusivity along the perivascular space (ALPS index), a possible indirect indicator of glymphatic system activity. MATERIALS AND METHODS: This study included the diffusion magnetic resonance imaging (MRI) data of 317 people with sleep disruption and 515 healthy controls (HCs) from the Human Connectome Project (WU-MINN HCP 1200). The ALPS index was calculated automatically based on diffusion tensor image analysis (DTI)-ALPS of diffusion MRI. The ALPS index of the sleep disruption and HC groups was compared using general linear model (GLM) analysis with covariates, such as age, sex, level of education, and intracranial volume. In addition, to confirm the relationship between sleep quality and the ALPS index in the sleep disruption group as well as evaluate the effect of each PSQI component on the ALPS index, correlation analyses between the ALPS indices and PSQI scores of all the components and between the ALPS index and each PSQI component was performed using GLM analysis with the abovementioned covariates, respectively. RESULTS: The ALPS index was significantly lower in the sleep disruption group than in the HC group (p = 0.001). Moreover, the ALPS indices showed significant negative correlations with the PSQI scores of all the components (false discovery rate [FDR]-corrected p < 0.001). Two significant negative correlations were also found between the ALPS index and PSQI component 2 (sleep latency, FDR-corrected p < 0.001) and 6 (the use of sleep medication, FDR-corrected p < 0.001). CONCLUSION: Our findings suggest that glymphatic system impairment contributes to sleep disruption in young adults.

Intranodal Embolization for Groin Lymphocele.

Purpose: Intranodal embolization using n-butyl cyanoacrylate glue is an emerging treatment option for persistent lymphatic leakage. This report describes the procedure details of intranodal embolization for groin lymphocele and evaluates the efficacy of intranodal embolization at our institution via retrospective chart review. Material and Methods: Nine consecutive patients (six men and three women; median age, 77.4 years; range, 43-95 years) who underwent intranodal embolization for groin lymphocele between January 2017 and December 2019 were included as study subjects. Intranodal lymphangiography with iodinated contrast was performed to confirm lymphatic leakage, followed by intranodal embolization using n-butyl cyanoacrylate glue mixed with iodized oil for all nine patients. The etiologies of lymphocele, technical and clinical success rates of intranodal embolization, duration of treatment, follow-up period, and acute and chronic complications were retrospectively investigated. Results: The etiologies of groin lymphoceles were the cutdown access of inguinal vessels (n = 7), lymph node biopsy (n = 1), and trauma (n = 1). The technical and clinical success rates of both lymphangiography and subsequent intranodal embolization were 100%. For intranodal embolization, 16.7%-33.3% n-butyl cyanoacrylate glue was used. The median duration of treatment was 2 days (range, 1-13 days). The follow-up period lasted 0-895 days (median, 9 days). No acute or chronic complications were observed. Conclusions: In this study, intranodal embolization showed promising results for groin lymphocele with a short duration of treatment with a median of 2 days. Intranodal embolization using n-butyl cyanoacrylate glue could be a treatment option for persistent groin lymphocele. However, further research is warranted to further evaluate the efficacy of intranodal embolization.

Anomalous retro-psoas iliac artery in a patient with right renal cancer: A case report.

Anomalous retro-psoas artery is an extremely rare congenital anomaly of the iliac arteries reported in the English-language literature. Using contrast-enhanced computed tomography, we incidentally diagnosed an anomalous retro-psoas artery in a 60-year-old male patient with right renal cancer. Although anomalous retro-psoas artery is extremely rare and mostly asymptomatic, knowledge of it is needed to avoid severe vascular complications in the event of vascular intervention and surgery.

Hybrid emergency room system improves timeliness of angioembolization for pelvic fracture.

BACKGROUND: Timely angioembolization (AE) is known to improve outcomes of patients with hemorrhage resulting from pelvic fracture. The hybrid emergency room system (HERS) is a novel trauma resuscitation room equipped with a computed tomography scanner, fluoroscopy equipment, and an operating room setup. We hypothesized that the HERS would improve the timeliness of AE for pelvic fracture. METHODS: A retrospective medical record review of patients who underwent AE for pelvic fracture at our institution from April 2015 to December 2018 was conducted. Patients' demographics, location of AE, Injury Severity Score, Revised Trauma Score, probability of survival by the trauma and injury severity score (TRISS Ps) method, presence of interventional radiologists (IRs) upon patient arrival, time from arrival to AE, and in-hospital mortality were analyzed. These data were compared between patients who underwent AE in the HERS (HERS group) and in the regular angio suite (non-HERS group). RESULTS: Ninety-six patients met the inclusion criteria. The HERS group comprised 24 patients, and the non-HERS group, 72 patients. Interventional radiologists were more frequently present upon patient arrival in the HERS than non-HERS group (IRs, 79% vs. 22%, p < 0.01). The time from arrival to AE was shorter in the HERS than non-HERS group (median [range], 46 [5-75] minutes vs. 103 [2-690] minutes, p < 0.01). There were no differences in the rate of in-hospital mortality (13% vs. 15%, p = 0.52) between the two groups. Survivors in the HERS group had a lower probability of survival by the trauma and injury severity score (median [range], 61% [1%-98%] vs. 93% [1%-99%], p < 0.01) than survivors in the non-HERS group. CONCLUSION: The HERS improved the timeliness of AE for pelvic fracture. More severely injured patients were able to survive in the HERS. The new team building involving the addition of IRs to the traditional trauma resuscitation team will enhance the benefit of the HERS. LEVEL OF EVIDENCE: Therapeutic, level IV.

Bidirectional ventricular tachycardia induced by caffeine poisoning.

Bidirectional ventricular tachycardia (BVT) is a tachyarrhythmia characterized by 180-degree beat-to-beat alteration in the QRS axis. BVT is traditionally known as an electrocardiography (ECG) finding pathognomonic of digitalis poisoning and a hallmark of catecholamine-induced ventricular tachycardia. Apart from digitalis poisoning, aconitine poisoning is the only reported cause of poisoning-related BVT, and no report of caffeine-poisoning-related BVT is as yet available. A-27-year-old woman was transported to hospital with cardiac arrest from ventricular fibrillation after taking a massive dose of a caffeine-containing supplement (corresponding to 6 g of caffeine) 6 h before presentation. Return of spontaneous circulation (ROSC) was achieved by defibrillation. She developed BVT after ROSC. Hemodialysis was performed to remove the causative drug from the blood, with subsequent resolution of BVT and hemodynamic stabilization. At presentation, she had a blood caffeine concentration of 232 µg/mL. A suggested mechanism of development of BVT is that increased intracellular calcium concentration causes delayed afterdepolarization, which induces alternate occurrence of triggered activities within different His-Purkinje fibers, and thereby produces characteristic ECG findings. Caffeine acts on the ryanodine receptor to promote calcium release from the sarcoplasmic reticulum, and thus can induce BVT via the same mechanism. Caffeine poisoning can be treated by dialysis. In cases of BVT induced by caffeine poisoning, hemodynamic stabilization can be achieved by emergency dialysis.

Design and characteristics of an agar additive polymer gel dosimeter.

Herein, we investigate the use of agar and gelatin in a polymer gel dosimeter. The polymer gel is enclosed in a vinyl film to obtain a dosimeter of arbitrary shape and maintain the shape at room temperature. The resulting polymer gel dosimeter could preserve its shape across a wide temperature range. Excluding the surface region, the obtained dose distribution was within 3% of that determined in an ionization chamber.

Wavefront measurement interferometry at the operational wavelength of extreme-ultraviolet lithography.

Two basic types of interferometer, a point diffraction interferometer (PDI) and a lateral shearing interferometer (LSI) suitable for operation in the extreme-ultraviolet (EUV) wavelength region, are described. To address the challenges of wavefront measurement with an accuracy of 0.1 nm rms, we present a calibration method for the PDI that places a mask with two large windows at the image plane of the illumination point light source and a general approach to deriving the phase-shift algorithm series that eliminates the undesired zeroth-order effect in the LSI. These approaches to improving the measurement accuracy were experimentally verified by the wavefront measurements of a Schwarzschild-type EUV projection lens.