Gadoteridol-enhanced MRI of the breast: can contrast agent injection rate impact background parenchymal enhancement?

Background Normal background parenchymal enhancement (BPE) is a dynamic parameter affected by multiple factors. Purpose To determine whether contrast agent injection rate affects the degree of BPE in women undergoing breast magnetic resonance imaging (MRI). Material and Methods A total of 85 patients included in our prospective study randomly received 0.1 mmol/kg gadoteridol at a rate of 3 mL/s (group A; n = 46) or 2 mL/s (group B; n = 39). Breast MRI was performed at 3T using a standard protocol including postcontrast axial 3D GRE T1-weighted sequences. Two expert breast radiologists, blinded to clinical and radiological information, independently quantified BPE on early postcontrast subtracted images, assigning a score of 1–4. Mean comparison and regression analysis were performed to assess the influence of injection rate on BPE. Results Groups were homogeneous in terms of age and final BI-RADS score. The mean BPE score was significantly lower among patients in group A (mean of two readers: 1.36 vs. 1.90; P < 0.01) with 70%–72% of patients assigned a BPE score of 1, compared with 36%–38% of patients in group B. Lower BPE scores were noted with the higher flow rate in subgroup analyses of both pre- and postmenopausal women, although the effect was more evident in premenopausal women. Regression analysis confirmed that the likelihood of a BPE 1 score was significantly increased with a higher flow rate ( P < 0.01). The inter-reader agreement was excellent (0.83). Conclusion A higher contrast agent injection flow rate (3 mL/s) during breast MRI significantly reduces the degree of BPE, potentially allowing improved diagnostic accuracy by reducing false-positive and false-negative findings.

Febrile torticollis in an infant: what is your diagnosis?

Retropharyngeal abscess is a rare but serious infection, in children, it is often secondary to upper respiratory tract infections.We report the case of an 18-month-old infant admitted to the emergencies for acute febrile torticolis. A computed tomographic (CT) scan with contrast agent injection revealed a collection of the retropharyngeal space; management consisted of triple antibiotic therapy and transoral drainage. The evolution was made towards a clinical and biological improvement. Retropharyngeal abscess should be suspected in front of dysphagia, cervical stiffness associated with a febrile syndrome, CT scan confirms the diagnosis and early management by intravenous antibiotic therapy whether or not combining surgical drainage, which remains a subject of discussion. Early diagnosis and management help to avoid life-threatening complications.

Study on Establishing Reference Safe Concentrations of MRI Contrast Agents for Optimized Images: Paramagnetic Gd-DTPA-BMEA and Superparamagnetic Ferucarbotran

The purpose of this study is to establish the minimal injection doses of magnetic resonance imaging (MRI) contrast agents that can achieve optimized images while improving the safety of injectable MRI drugs. Gadolinium-diethylenetriamine penta-acetic acid (Gd-DTPA) and ferucarbotran, commonly used in clinical practice, were selected and evaluated with in vitro and in vivo experiments. MRI was acquired using T1-weighted (T1W) and T2-weighted (T2W) sequences, and the results were quantitatively analyzed. For in vitro experiments, results showed that T1W and T2W images were optimal when Gd-DTPA-bisamide (2-oxoethyl) (Gd-DTPA-BMEA) and ferucarbotran were diluted to a volume percentage of 0.6% and 0.05%; all comparisons were significant differences in grayscale statistics using one-way analysis of variance (ANOVA). For in vivo experiments, the contrast agent with optimal concentration percentages determined from in vitro experiments were injected into mice with an injection volume of 100 μL, and the images of brain, heart, liver, and mesentery before and after injection were compared. The statistical results showed that the p values of both T1W and T2W were less than 0.001, which were statistically significant. Under safety considerations for MRI contrast agent injection, optimized MRI images could still be obtained after reducing the injection concentration, which can provide a reference for the safety concentrations of MRI contrast agent injection in the future.

Optimum concentration of iodine contrast agent injection for best stent visualization using Neuroform Atlas stent during stent-assisted coil embolization: Case reviews based on in vitro experiments

Background: The present study aimed to evaluate the influence of contrast agent concentration (Conc) on the visibility of Neuroform Atlas in vitro and in clinical cases. Methods: A plastic tube was filled with several Conc. in saline (experiment 1) and blood (experiment 2). Thereafter, the Neuroform Atlas was placed around the plastic tube in an acrylic shield case. In experiment 3, the Neuroform Atlas was placed in the internal carotid artery of the endo vascular evaluator endovascular training system with an injection of several Conc in saline. Five slices of the axial images obtained using the 3D-cone-beam computed tomography (3D-CBCT) with the digital subtraction angiography system were evaluated. A 1-cm2 circular center, which showed the contrast agent in saline or blood, was determined as the region of interest, and its pixels were evaluated. Results: Radiation density (Rd) was directly proportional to the contrast agent in saline and blood (experiment 1: (Rd (pixel)) = 6.8495 × (concentration (%)) + 152.72 (R2 = 0.99), experiment 2: (Rd (pixel)) = 6.2485 × (concentration (%)) + 167.42 (R2 = 0.9966), experiment 3: (Rd (pixel)) = 10.287 × (concentration (%)) + 108.26 (R2 = 0.993)]. Rd calculated similarly in our cases (concentration varied from 5% to 8%) was between the range of “Rd of experiment 2” and “Rd of experiment 3.” Conclusion: Based on our in vitro experiments, with 5–8% concentration, Neuroform Atlas stent deployment with complete neck coverage by the bulging stent and wall apposition was visualized on 3D-CBCT.

A Rare Case of Sigmoid Colon Carcinoma in Incarcerated Inguinal Hernia

Incarcerated inguinal hernia is a common diagnosis in patients presenting a painful and nonreducible groin mass. Although the diagnosis is usually made by physical examination, the content of the hernia sac and the extent of the surgical operation may vary and can require multimodal imaging integration (e.g., ultrasonography, computed tomography); the usual finding is a segment of small bowel and, less commonly, large bowel. We present an extremely rare case of a sigmoid cancer incarcerated in a left inguinal hernia and infiltrating the spermatic cord. The patient underwent whole-body computed tomography (CT) with contrast agent injection for staging, followed by a left hemicolectomy paralleled by a unilateral orchiectomy.

A case of esophagojejunal varices rupture after proximal gastrectomy with double-tract reconstruction

Background The varices after proximal or total gastrectomy are uncommon because the supplying vessels are all divided. Emergent upper gastrointestinal endoscopy is the cornerstone of first-line management for the diagnosis and treatment of esophageal varices. However, there is no widely accepted standard strategy for esophagojejunal varices. We report a patient with esophagojejunal varices rupture 3 months after proximal gastrectomy treated with percutaneous transhepatic obliteration. Case presentation A 50-year-old man who had undergone proximal gastrectomy with double-tract reconstruction for esophagogastric junctional cancer 3 months before was admitted to the hospital due to gastrointestinal perforation. We performed emergency surgery and abdominal symptoms and inflammatory response improved postoperative. However, on POD3, he had eruptive bleeding at the just anal side of esophagojejunal anastomosis. Endoscopic clipping was unsuccessful because the mucosa was fragile and easily lacerated. Contrast-enhanced CT scan revealed the dilatation of the jejunal vein flowing into the ascending jejunal limb. Therefore, he was diagnosed as esophagojejunal varices rupture and percutaneous transhepatic obliteration (PTO) was tried for hemostasis. The portal and superior mesenteric veins were catheterized with the percutaneous transhepatic approach. Contrast agent injection into the jejunal branch demonstrated retrograde flow to the azygos vein through esophagojejunal varices. The microcatheter was inserted into the variceal blood supply branch and 10 mL of 5% ethanolamine oleate with iopamidol was injected. After obliteration therapy, the superior mesenteric venogram showed complete occlusion of the variceal supply branch. The patient was discharged from the hospital without any complications after 14 days. Conclusion PTO can be effective for gastroesophageal varices rupture with a dilated jejunal vein of the ascending limb, few supplying vessels, and little ascites.

P1585 Cardiac magnetic resonance estimated extracellular volume fraction, but not native T1 mapping, detects scar in patients referred for cardiac resynchronization therapy

Funding Acknowledgements The study was supported by Center for Cardiological Innovation Background Myocardial scar burden (focal fibrosis) is associated with poor response to cardiac resynchronization therapy (CRT), and should preferably be detected prior to device implantation. Late gadolinium enhancement (LGE) cardiac magnetic resonance (CMR) is considered reference standard for scar detection, but is not available in renal failure. Diffuse fibrosis is assessed by T1 mapping CMR with or without calculation of extracellular volume fraction (ECV). The method is vulnerable to partial volume effects, thus subendocardial tissue is most often not included in mapping analyses. Whether the contrast-free native T1mapping could replace LGE in the preoperative evaluation of patients referred for CRT is unknown. Purpose To investigate if native T1 mapping and calculation of ECV can adequately detect scar in patients referred for CRT. Methods Scar was quantified as percentage segmental LGE in 45 patients (age 65 ± 10 years, 71% male, QRS-width 165 ± 17ms) referred for CRT. In total 720 segments were analyzed, and LGE≥50% was considered transmural scar. T1-mapping before and after contrast agent injection was performed in all patients. ECV was calculated based on the ratio between tissue T1 relaxation change and blood T1 relaxation change after contrast agent injection, corrected for the haematocrit level. The agreement between native T1/ECV and scar was evaluated with receiver operating characteristic (ROC) curves with calculation of area under the curve (AUC) and 95% confidence interval (CI). Results LGE was present in 255 segments, 465 segments were without LGE. Average native T1 in segments with LGE was 1028 ± 88 ms, and 1040 ± 60 ms in segments without LGE (p = 0.16). The corresponding numbers for ECV were 38.7 ± 10.9% and 30.0 ± 4.7%, p &lt; 0.001. Native T1 showed poor agreement to scar independent of scar size (AUC = 0.532, 95% CI 0.485-0.578 for scars of all sizes, and AUC = 0.572, 95% CI 0.495-0.650 for transmural scars). ECV, on the other hand, showed reasonable agreement with scar of all sizes (AUC = 0.777, 95% CI 0.739-0.815), and good agreement with transmural scars (AUC = 0.856, 95% CI 0.811-0.902). (Figure) Conclusion The contrast-free CMR technique T1 mapping does not adequately detect scars in patients referred for CRT. Adding post contrast T1 measurements and calculating ECV improves accuracy, especially for transmural scars. Future studies should investigate if diffuse fibrosis could be predictive of CRT response. Abstract P1585 Figure. Detection of transmural scars