Silent Embolic Infarction after Neuroform Atlas Stent-Assisted Coiling of Unruptured Intracranial Aneurysms

OBJECTIVE

There is still controversy regarding whether neck remodeling stent affects the occurrence of silent embolic infarction (SEI) after aneurysm coiling. Thus, the aim of the present study is to investigate the incidence of SEI after stent-assisted coiling (SAC) using Neuroform Atlas Stent (NAS) and possible risk factors. This study also includes a comparison with simple coiling group during the same period to estimate the impact of NAS on the occurrence of SEI.

METHODS

This study included a total of 96 unruptured intracranial aneurysms in 96 patients treated with SAC using NAS. Correlations of demographic data, aneurysm characteristics, and angiographic parameters with properties of SEI were analyzed. The incidence and characteristics of SEI were investigated in 28 patients who underwent simple coiling during the same period, and the results were compared with the SAC group.

RESULTS

In the diffusion-weighted imaging obtained on the 1st day after SAC, a total of 106 SEI lesions were observed in 48 (50%) of 96 patients. Of these 48 patients, 38 (79.2%) had 1-3 lesions. Of 106 lesions, 74 (69.8%) had a diameter less than 3 mm. SEI occurred more frequently in older patients (≥60 years, p=0.013). The volume of SEI was found to be significantly increased in older age (≥60 years, p=0.032), hypertension (p=0.036), and aneurysm size ≥5 mm (p=0.047). The incidence and mean volume of SEI in the SAC group (n=96) were similar to those of the simple coiling group (n=28) during the same period.

CONCLUSION

SEIs are common after NAS-assisted coiling. Their incidence in SAC was comparable to that in simple coiling. They occurred more frequently at an older age. Therefore, the use of NAS in the treatment of unruptured intracranial aneurysm does not seem to be associated with an increased risk of thromboembolic events if antiplatelet premedication has been performed well.

Decreased Bleeding-Related Adverse Events Using Track Embolization with Gelatin Sponge Slurry after Percutaneous Liver Biopsy: A Propensity Score-Matched Study

PURPOSE

To evaluate the effectiveness of track embolization using gelatin sponge slurry in percutaneous ultrasound (US)-guided liver biopsy.

MATERIALS AND METHODS

Among the 543 patients who underwent percutaneous US-guided liver biopsies between September 2018 and August 2021, 338 who did not undergo track embolization and 105 who underwent track embolization were included in the analysis. All procedures were performed with 18-gauge coaxial core biopsy needles. Patients' laboratory data were reviewed. Patients in both groups were subdivided into the following 2 groups: (a) those with targeted biopsy for a focal liver lesion and (b) those with nontargeted biopsy for a liver parenchyma. Moreover, postbiopsy events, such as transfusion and transarterial embolization, were assessed. To minimize selection bias, propensity score matching (PSM) was performed.

RESULTS

After PSM, all factors that could affect bleeding risk were well-matched and well-balanced between the 2 groups (P > .474). In the non-track embolization group, 17 (16.2%) patients experienced major or minor bleeding-related adverse events (AEs). In contrast, in the track embolization group, only 5 (4.8%) patients experienced major or minor bleeding-related AEs, which was significantly lower than that in the non-track embolization group (P = .007). All 5 (4.8%) cases of major bleeding-related AEs were observed in the non-track embolization group (P = .024).

CONCLUSIONS

In this study, a retrospective analysis was performed using PSM for percutaneous US-guided liver biopsy. Track embolization using gelatin sponge slurry is significantly superior in the prevention of bleeding-related AEs after US-guided liver biopsy.

[Intervention for Chest Trauma and Large Vessel Injury]

Trauma is an injury to the body that involves multiple anatomical and pathophysiological changes caused by forces acting from outside the body. The number of patients with trauma is increasing as our society becomes more sophisticated. The importance and demand of traumatology are growing due to the development and spread of treatment and diagnostic technologies. In particular, damage to the large blood vessels of the chest can be life-threatening, and the sequelae are often severe; therefore, diagnostic and therapeutic methods are becoming increasingly important. Trauma to non-aortic vessels of the thorax and aorta results in varying degrees of physical damage depending on the mechanism of the accident and anatomical damage involved. The main damage is hemorrhage from non-aortic vessels of the thorax and aorta, accompanied by hemodynamic instability and coagulation disorders, which can be life-threatening. Immediate diagnosis and rapid therapeutic access can often improve the prognosis. The treatment of trauma can be surgical or interventional, depending on the patient's condition. Among them, interventional procedures are increasingly gaining popularity owing to their convenience, rapidity, and high therapeutic effectiveness, with increasing use in more trauma centers worldwide. Typical interventional procedures for patients with thoracic trauma include embolization for non-aortic injuries and thoracic endovascular aortic repair for aortic injuries. These procedures have many advantages over surgical treatments, such as fewer internal or surgical side effects, and can be performed more quickly than surgical procedures, contributing to improved outcomes for patients with trauma.

Additional rescue stenting with Neuroform Atlas stents during stent-assisted coiling of saccular aneurysms

OBJECTIVE

Overlapping stenting is sometimes attempted during endovascular treatment of cerebral aneurysm as a rescue for coil herniation, stent mal-positioning, or in-stent thrombosis. We retrospectively evaluated the efficacy and safety of additional rescue stenting (ARS) in telescoping fashion with Neuroform Atlas stent (NAS) during stent-assisted coiling of saccular aneurysms.

METHODS

We collected clinical and radiological data of patients with saccular aneurysms treated with ARS using NASs between March 2018 and December 2021. Y or X-stent-assisted coiling technique was excluded.

RESULTS

Eighteen unruptured and 5 ruptured aneurysms in 23 patients were treated with ARS using NASs. Sizes of aneurysms ranged from 2.0 mm to 10.0 mm (mean: 5.0 mm). Immediate angiographic results were complete occlusion in 11 aneurysms, residual neck in 4 aneurysms, and residual sac in 8 aneurysms. Peri-operative morbidity was 4.3 %. Nineteen of 23 patients underwent follow-up conventional angiography (mean, 9.9 months). Results showed progressive occlusion in 10 (52.6 %) cases and asymptomatic in-stent stenosis in 3 (15.8 %) cases. At the end of the observation period (mean, 17.4 months), all 18 patients without subarachnoid hemorrhage had excellent clinical outcomes (mRS of 0), except one (mRS of 1). Of five patients with subarachnoid hemorrhage, four had a favorable outcome (mRS of 0-1), while the other one was dependent (mRS of 4).

CONCLUSION

In this report on 23 patients, ARS with NASs for treating saccular aneurysms showed good technical safety with favorable clinical and angiographic outcomes. However, delayed in-stent stenosis was not uncommon. Thus, regular imaging follow-up is required.

[Endovascular Treatment for Head and Neck Trauma]

Trauma to the head and neck region can have serious consequences for vital organs such as the brain, and injuries to blood vessels can cause permanent neurological damage or even death. Thus, prompt treatment of head and neck vessels is crucial. Although the level of evidence is moderate, an increasing amount of research indicates that endovascular treatments can be a viable alternative to traditional surgery or medical management. Embolization or reconstructive endovascular procedures can significantly improve patient outcomes. This article provides an overview of various endovascular options available for specific clinical scenarios, along with examples of cases in which they were employed.

Comparing carotid endarterectomy and carotid artery stenting: retrospective single-center analysis

BACKGROUND

Extracranial cerebrovascular diseases represent approximately 20% of ischemic stroke cases. Carotid endarterectomy (CEA) was the gold standard procedure for carotid artery stenosis treatment until the introduction of carotid artery stenting (CAS) in the 1980s. While there have been several multicenter randomized trials comparing CEA and CAS, a more efficacious procedure has not been conclusively distinguished. This study reports the results of CAS versus CEA in patients with symptomatic or asymptomatic carotid stenosis and compares them with those from other studies.

METHODS

This study is a single-center retrospective study and included patients who underwent CAS and CEA as elective surgery between January 2012 and December 2020. The final analysis included patient baseline characteristics, postoperative complications, and patient outcomes.

RESULTS

The 235 patients included were assigned to the CAS (n=128) and CEA (n=107) groups. Within 30 days postoperatively, no significant differences were noted in myocardial infarction [n=1, 0.8% (CAS); n=1, 0.9% (CEA); P=0.899], cerebral infarction [n=4, 3.1% (CAS); n=1, 0.9% (CEA); P=0.247], and patient mortality [n=1, 0.8% (CAS); n=0, 0% (CEA); P=0.247].

CONCLUSIONS

In elective surgery, CAS and CEA had the same effect of preventing cerebral infarction with no difference in postoperative complications.

Stacking ensemble learning model to predict 6-month mortality in ischemic stroke patients

Patients with acute ischemic stroke can benefit from reperfusion therapy. Nevertheless, there are gray areas where initiation of reperfusion therapy is neither supported nor contraindicated by the current practice guidelines. In these situations, a prediction model for mortality can be beneficial in decision-making. This study aimed to develop a mortality prediction model for acute ischemic stroke patients not receiving reperfusion therapies using a stacking ensemble learning model. The model used an artificial neural network as an ensemble classifier. Seven base classifiers were K-nearest neighbors, support vector machine, extreme gradient boosting, random forest, naive Bayes, artificial neural network, and logistic regression algorithms. From the clinical data in the International Stroke Trial database, we selected a concise set of variables assessable at the presentation. The primary study outcome was all-cause mortality at 6 months. Our stacking ensemble model predicted 6-month mortality with acceptable performance in ischemic stroke patients not receiving reperfusion therapy. The area under the curve of receiver-operating characteristics, accuracy, sensitivity, and specificity of the stacking ensemble classifier on a put-aside validation set were 0.783 (95% confidence interval 0.758-0.808), 71.6% (69.3-74.2), 72.3% (69.2-76.4%), and 70.9% (68.9-74.3%), respectively.

Diffusion Kurtosis MR Imaging of Invasive Breast Cancer: Correlations With Prognostic Factors and Molecular Subtypes

BACKGROUND

The associations between diffusion kurtosis imaging (DKI)-derived parameters and clinical prognostic factors of breast cancer have not been fully evaluated; this knowledge may have implications for outcome prediction and treatment strategies.

PURPOSE

To determine associations between quantitative diffusion parameters derived from DKI and diffusion-weighted imaging (DWI) and the prognostic factors and molecular subtypes of breast cancer.

STUDY TYPE

Retrospective.

POPULATION

A total of 383 women (mean age, 53.8 years; range, 31-82 years) with breast cancer who underwent preoperative breast MRI including DKI and DWI.

FIELD STRENGTH/SEQUENCE

A 3.0 T; DKI using a spin-echo echo-planar imaging (EPI) sequence (b values: 200, 500, 1000, 1500, and 2000 sec/mm² ), DWI using a readout-segmented EPI sequence (b values: 0 and 1000 sec/mm² ) and dynamic contrast-enhanced breast MRI.

ASSESSMENT

Two radiologists (J.Y.K. and H.S.K. with 9 years and 1 year of experience in MRI, respectively) independently measured kurtosis, diffusivity, and apparent diffusion coefficient (ADC) values of breast cancer by manually placing a regions of interest within the lesion. Diffusion measures were compared according to nodal status, grade, and molecular subtypes.

STATISTICAL TESTS

Kruskal-Wallis test, Mann-Whitney U test with Bonferroni correction, receiver operating characteristic (ROC) analysis, and multivariate logistic regression analysis. (Statistical significance level of P < 0.05).

RESULTS

All diffusion measures showed significant differences according to axillary nodal status and histological grade. Kurtosis showed significant differences among molecular subtypes. The luminal subtype (median 1.163) showed a higher kurtosis value compared to the HER2-positive (median 0.962) or triple-negative subtypes (median 1.072). ROC analysis for differentiating HER2-positive from luminal subtypes revealed that kurtosis yielded the highest area under the curve of 0.781. In multivariate analyses, kurtosis remained a significant factor associated with differentiation between HER2-positive and luminal (odds ratio [OR] = 0.993), triple-negative and luminal (OR = 0.995), and HER2-positive and triple-negative subtypes (OR = 0.994).

DATA CONCLUSION

Quantitative diffusion parameters derived from DKI and DWI are associated with prognostic factors for breast cancer. Moreover, DKI-derived kurtosis can help distinguish between the molecular subtypes of breast cancer.

EVIDENCE LEVEL

4 TECHNICAL EFFICACY: 3.

Spine-Hip Discordance and FRAX assessment Fracture Risk in Postmenopausal Women with Osteopenia from Concordant Diagnosis Between Lumbar Spine and Femoral Neck

The diagnostic criteria proposed by the World Health Organization did not consider the discrepancy in diagnosis between lumbar spine (LS) and femoral neck (FN) and the clinical implications is unclear. Therefore, this retrospective study evaluated the probability of fracture risk in postmenopausal women with lumbar spine (LS)-femoral neck (FN) bone mineral density (BMD) discordance or not Patients included 1066 healthy postmenopausal women (median age 55.5 years) who visited our hospital for a health check-up between May 2013 and April 2017. Discordance was defined as a difference of one or two degrees between LS BMD and FN BMD. TBS was calculated from dual energy absorptiometry (DXA) images. Fracture risk was assessed using the Fracture Risk Assessment Tool (FRAX), including TBS-adjusted FRAX Seven hundred and two patients (65.9%) showed concordant LS and FN results, whereas 364 patients (34.1%) exhibited discordance. Normal BMD was found in 519 concordant patients (73.9%). Concordant patients showed significantly higher FRAX scores, including TBS-adjusted FRAX results, than discordant patients with low LS or FN. Furthermore, FRAX results in concordant osteopenia patients were similar to that of osteoporosis patients with osteopenia or a normal result at one site. FRAX and TBS-adjusted FRAX results in concordant osteopenia patients were comparable to that of discordant osteoporosis patients We concluded that patients with colncordant osteopenia in both the FN and LS should be managed in a similar way to patients with discordant osteoporosis.

Tumor stiffness measured by shear-wave elastography: association with disease-free survival in women with early-stage breast cancer

OBJECTIVE

To determine whether shear-wave elastography (SWE)-measured tumor stiffness is associated with disease-free survival in females with early-stage invasive breast cancer.

METHODS

This retrospective study included 202 consecutive females (mean age, 52.9 years; range, 25-84 years) with newly diagnosed T1-two breast cancer who underwent preoperative SWE between April 2015 and January 2016. Tumor stiffness was assessed and quantitative SWE features of each breast lesion were obtained by a breast radiologist. Cox proportional hazard models were used to identify associations between SWE features and disease-free survival after adjusting for clinicopathologic factors.

RESULTS

Fifteen (7.4%) patients exhibited recurrence after a median follow-up of 56 months. Mean (Emean), minimum, and maximum elasticity values were higher in females with recurrence than in those without recurrence (184.4, 138.3, and 210.5 kPa vs 134.9, 101.7, and 159.8 kPa, respectively; p = 0.005, p = 0.005, and p = 0.012, respectively). Receiver operating characteristics curve analysis for prediction of recurrence showed that Emean yielded the largest area under the curve (0.717) among the quantitative SWE parameters, and the optimal cut-off value was 121.7 kPa. Multivariable Cox proportional hazards analysis revealed that higher Emean (>121.7 kPa) [adjusted hazard ratio (HR), 10.01; 95% CI: 1.31-76.33; p = 0.026] and lymphovascular invasion (adjusted HR, 7.72; 95% CI: 1.74-34.26; p = 0.007) were associated with worse disease-free survival outcomes.

CONCLUSION

Higher SWE-measured Emean was associated with worse disease-free survival in females with early-stage invasive breast cancer.

ADVANCES IN KNOWLEDGE

Tumor stiffness assessed with shear-wave elastography might serve as a quantitative imaging biomarker of disease-free survival in females with T1-two breast cancer.

The Clinical Value of Periventricular White Matter Hyperintensity on MRI in Sudden Sensorineural Hearing Loss

OBJECTIVES

To assess the clinical value of periventricular white matter hyperintensity (PWMH) found on brain magnetic resonance imaging (MRI) in patients with sudden sensorineural hearing loss (SSNHL).

METHODS

In this prospective study, 115 patients who were diagnosed with SSNHL aged between 55 and 75 years were analyzed. All subjects underwent brain MRI and were divided into a PWMH and control groups, depending on the presence of PWMH on MRI. PWMH was subdivided into 3 groups according to severity. Pure-tone average results and hearing gain were compared between the 2 groups before treatment and 2 months after treatment. Hearing improvement was assessed using Sigel's criteria.

RESULTS

A total of 106 patients (43 in the PWMH group and 63 in the control group) finally completed the 2-month follow-up. Average hearing gain in the PWMH group was significantly higher than in the control group (34.8 ± 20.3 and 25.9 ± 20.3, respectively, P = .029). PWMH score 1 showed significantly better hearing levels and hearing gain compared to PWMH score 3 and the control group. Multivariate analysis revealed that younger age, better initial hearing level, and the presence of PVWM score 1 were associated with good recovery.

CONCLUSIONS

The presence of PWMH score 1 on brain MRI in patients with SSNHL was associated with better treatment response and was a good prognostic factor in a multivariate analysis while the hearing recovery in more severe PWMH (scores 2, 3) was not different from the control group.

The usefulness of Valsalva computed tomography as an assessment tool for the Eustachian tube

PURPOSE

To determine the usefulness of 'computed tomography (CT) with Valsalva maneuver (VM)' (Valsalva CT) for localizing lesions of the eustachian tube (ET) and identifying characteristics of ET dysfunction (ETD).

MATERIALS AND METHODS

In this case-control study, 12, 17, and 25 patients with obstructive ETD (OETD), patulous eustachian tube (PET), and conductive hearing loss (control), respectively, underwent Valsalva CT in the supine position. The visualized length to total length ratio of the cartilaginous ET (VTRET) with and without VM were compared in the three groups. In the OETD group, obstructed areas of the ET were identified on multiplanar reconstructed images.

RESULTS

VTRET without VM in the PET group was significantly higher than that in the control and OETD groups (p-values, 0.003 and 0.007, respectively). However, there was no significant difference between the control and OETD groups (p = 0.053). VTRET with VM in the PET group was significantly higher than that in the other two groups (p < 0.001), whereas that in the control group was significantly higher than that in the OETD group (p < 0.001). In the OETD group, the obstructed area was clearly identified, and there were one, one, six, and eight patients in the isthmus; bony portion and isthmus; bony portion, isthmus, and cartilaginous portion; and isthmus and cartilaginous portion subgroups, respectively.

CONCLUSION

Valsalva CT is particularly valuable as a visualization assessment tool for identifying obstructed areas in the OETD. It may help future research of disease-specific mechanical characteristics of the ET on controlling pressure variables.

Endovascular treatment of the vertebral artery origin stenosis by using the closed-cell, self-expandable Carotid Wallstent

BACKGROUND

Endovascular treatment has been considered a good alternative to surgery for symptomatic vertebral artery origin stenosis (VAOS) due to the high risk of morbidity associated with surgery. The purpose of this study was to evaluate the feasibility and efficacy of insertion of the closed-cell, self-expandable Carotid Wallstent for the treatment of VAOS.

METHODS

The records of 72 patients with VAOS refractory to adequate medication who were treated by endovascular treatment with the Carotid Wallstent from December 2006 to November 2018 were retrospectively evaluated.

RESULTS

Of the 72 patients, 43 presented with transient ischemic attacks. Forty-seven patients (65.3%) manifested other brachiocephalic stenoses; of these, 40 patients had occlusion, hypoplasia, or stenosis of the contralateral vertebral artery. Overall technical success (defined as 20% or less residual stenosis) was 100%. Procedure-related complications (n = 8, 11.1%) included sudden asystole (n = 1), acute in-stent thrombosis (n = 3), minor stroke (n = 3), and stent shortening (n = 1). All complications were resolved without permanent neurological deficit. Angiographic follow-up (mean, 13.0 months) was achieved in 49 patients and revealed in-stent restenosis in 1 patient (2.0%) and stent malposition by shortening in 2 patients (4.1%). Follow-up records were available in 57 patients (mean 15.6 months). Three of the 57 patients (n = 3, 5.3%) had recurrent symptoms of vertebrobasilar ischemia and none was retreated.

CONCLUSIONS

Endovascular treatment of symptomatic VAOS using the closed-cell, self-expandable Carotid Wallstent is technically feasible and effective in alleviating patient symptoms and for improving vertebrobasilar blood flow.

Kinetic Heterogeneity of Breast Cancer Determined Using Computer-aided Diagnosis of Preoperative MRI Scans: Relationship to Distant Metastasis-Free Survival

Background Higher peak enhancement and washout component values measured on preoperative breast MRI scans with computer-aided diagnosis (CAD) are presumed to be associated with worse recurrence-free survival. Purpose To investigate whether CAD-extracted kinetic features of breast cancer and the heterogeneity of these features at preoperative MRI are associated with distant metastasis-free survival in women with invasive breast cancer. Materials and Methods Consecutive women with newly diagnosed invasive breast cancer who underwent preoperative MRI were retrospectively evaluated between 2011 and 2012. A commercially available CAD system was used to extract the peak enhancement and delayed enhancement profiles of each breast cancer case from preoperative MRI data. The kinetic heterogeneity of these features (a measure of heterogeneity in the proportions of tumor pixels with delayed washout, plateau, and persistent components within a tumor) was calculated to evaluate intratumoral heterogeneity. Cox proportional hazards models were used to investigate the associations between CAD-extracted kinetic features and distant metastasis-free survival after adjusting for clinical-pathologic factors. Results A total of 276 consecutive women (mean age, 53 years) were evaluated. In 28 of 276 (10.1%) women, distant metastasis developed at a median follow-up of 79 months. A higher degree of kinetic heterogeneity was observed in women with distant metastases than in those without distant metastases (mean, 0.70 ± 0.2 vs 0.43 ± 0.3; P < .001). Multivariable Cox proportional hazards analysis revealed that a higher degree of kinetic heterogeneity (hazard ratio [HR], 19.2; 95% confidence interval [CI]: 4.2, 87.1; P < .001), higher peak enhancement (HR, 1.001; 95% CI: 1.000, 1.002; P = .045), the presence of lymphovascular invasion (HR, 3.3; 95% CI: 1.5, 7.5; P = .004), and a higher histologic grade (ie, grade 3) (HR, 2.2; 95% CI: 1.0, 4.9; P = .044) were associated with worse distant metastasis-free survival. Conclusion Higher values of kinetic heterogeneity and peak enhancement as determined with computer-aided diagnosis of preoperative MRI were associated with worse distant metastasis-free survival in women with invasive breast cancer. © RSNA, 2020 See also the editorial by El Khouli and Jacobs in this issue.

Safety and tolerability of iobitridol in cerebral angiography: a prospective, multicenter study

Background

To date, only a few data have demonstrated the safety of iodinated contrast media for cerebral angiography.

Purpose

To assess contrast-related adverse events after cerebral angiography using iobitridol.

Material and Methods

A total of 790 patients who underwent cerebral angiography at three tertiary hospitals in the Republic of Korea between November 2017 and October 2018 were prospectively enrolled in this study. We interviewed all patients and recorded their symptoms before they left the interventional clinic after the angiography procedure and during the seven-day follow-up visit. The primary endpoints were acute (within 1 h) and delayed (1 h–7 days) adverse events associated with iobitridol injection. We also visually graded the radiographic density and image quality as secondary endpoints.

Results

Acute adverse events were more common than delayed adverse events. Most adverse events were either mild (96.5%) or moderate (3.45%). Among the contrast-related adverse events, feeling of warmth (59.1%) and altered taste (17.5%) were the most common acute events, whereas headache (41.9%) and allergic skin reactions (20.0%) were the most common delayed events. All cerebral angiography showed optimal density and good/excellent image quality.

Conclusion

The findings of this study suggest that iobitridol is a safe and effective iodinated contrast medium for use in cerebral angiography.

Diffusion-weighted Imaging of Invasive Breast Cancer: Relationship to Distant Metastasis-free Survival

Background Combined minimum apparent diffusion coefficient (ADC) and ADC difference value may improve the diagnostic performance of breast diffusion-weighted imaging (DWI) compared with mean ADC. Purpose To investigate whether ADC parameters at DWI are associated with distant metastasis-free survival in women with invasive breast cancer. Materials and Methods Between 2013 and 2014, 258 consecutive women (mean age ± standard deviation, 50.9 years ± 10.5; age range, 23-85 years) with newly diagnosed invasive breast cancer who underwent preoperative MRI with DWI were evaluated. All DWI examinations were retrospectively reviewed by two radiologists blinded to clinical information. The mean, minimum, and maximum ADCs were measured by manually placing regions of interest within the lesions, and the ADC difference value (the difference between minimum and maximum ADCs) was calculated to evaluate intratumoral heterogeneity. Cox proportional hazards models were used to determine the associations between ADC parameters and distant metastasis-free survival after adjustment for clinical-pathologic factors. Results In 25 of the 258 women (9.7%), distant metastasis developed at a median follow-up of 51 months. The ADC difference value was higher in women with distant metastasis than in those without distant metastasis (mean, 0.743 × 10^-3 mm²/sec vs 0.566 × 10^-3 mm²/sec, respectively; P < .001). Multivariable Cox proportional hazards analysis showed that a higher ADC difference value (>0.698 × 10^-3 mm²/sec) (hazard ratio [HR], 4.5; 95% confidence interval [CI]: 2.0, 10.0; P < .001), presence of axillary node metastasis (HR, 3.3; 95% CI: 1.2, 9.3; P = .02), and estrogen receptor negativity (HR, 2.6; 95% CI: 1.2, 5.7; P = .02) were associated with poorer distant metastasis-free survival. Conclusion A higher apparent diffusion coefficient difference value at diffusion-weighted imaging is associated with poorer distant metastasis-free survival of women with invasive breast cancer. © RSNA, 2019 See also the editorial by Taourel in this issue.

The minimum percentage of triolein emulsion for studying cerebral vascular permeability with least brain edema

Background:

Triolein emulsion infusion into the brain produces transiently increased vascular permeability.

Objectives:

The purpose of this study was to find the minimum percentage of triolein emulsion required for studying vascular permeability with minimal brain edema.

Materials and Methods:

Sixty healthy cats were divided into six groups according to the concentration of emulsified triolein infused into the carotid artery: group 1, 0.125% (n = 10); group 2, 0.25% (n = 10); group 3, 0.5% (n = 10); group 4, 1% (n = 10); group 5, 2% (n = 10); and group 6, saline infusion (control group, n = 10). T2-, T1- and contrast enhanced T1-weighted MR images were obtained 2 hours after infusing triolein emulsion. Contrast enhancement ratios (CERs) and signal intensity ratios (SIRs) versus contralateral hemispheres were calculated. Statistical analysis was performed by analysis of variance followed by Tukey’s test. P values of ≤ 0.05 were considered significant.

Results:

The lesion hemispheres showed mild hyperintensity due to edema on T2-weighted images, and contrast enhancement on post-contrast T1-weighted images in cats of group 1-5. CERs showed statistically significant differences between the control group and group 3 (P = 0.006), group 4 (P = 0.003), and group 5 (P < 0.001). However, SIRs were significantly different between the control group and group 5 only (P < 0.001).

Conclusion:

The minimum concentration of triolein emulsion required to increase vascular permeability adequately with minimal brain edema in a cat model was 0.5%.

Hemorrhage in cerebral fat embolisms in a cat model using triolein dependent on the physical properties of triolein

PURPOSE

Hemorrhage is a finding of clinical fat embolism syndrome. The purpose of the present study was to evaluate the occurrence of hemorrhage in the cat brain by SW MR imaging after infusion of triolein as a bolus or as an emulsion into the carotid artery.

MATERIALS AND METHODS

Twenty-two cats were divided into two groups according to the type of triolein infused: group 1 (n = 11) was infused with a 0.1 ml triolein bolus, group 2 (n = 11) with triolein emulsion containing 0.1 ml triolein in 20 ml saline. SW imaging was performed before and after triolein infusion (at 2 h, 1 and 4 days). After MR imaging on day 4, cats were sacrificed and brains were immediately excised. Hemorrhage was evaluated using H&E staining.

RESULTS

Hemorrhage was observed in eight cats in group 1, in no cats in group 2. Hemorrhage on SW images was found to correspond with light microscopy.

CONCLUSIONS

SW images revealed hemorrhage in lesion hemispheres infused with triolein bolus. However, there was no evidence of hemorrhage infused with emulsified triolein. Thus, the occurrence of hemorrhage in cerebral fat embolism may depend on fat status.

Adenosine-stress low-dose single-scan CT myocardial perfusion imaging using a 128-slice dual-source CT: a comparison with fractional flow reserve

BACKGROUND

Coronary CT angiography (CCTA) allows accurate evaluation of coronary artery stenosis but has limitations in information on hemodynamic significance of stenotic lesions.

PURPOSE

To determine the feasibility of adenosine-stress low-dose single-scan CT myocardial perfusion imaging (MPI) using a 128-slice dual-source CT scanner for the diagnosis of hemodynamically significant coronary artery stenosis as defined by fractional flow reserve (FFR).

MATERIAL AND METHODS

This study was proved by the Institutional Review Board and informed consent was obtained from the patients before enrollment in the study. Ninety-seven patients with chest pain and low-to-intermediate pretest probability of coronary artery disease were prospectively enrolled. Adenosine-stress CCTA using ECG-correlated maximum tube current modulation (Mindose(®)) with 128-slice dual-source CT was performed in all 97 patients. In 37 patients (38.1%; 28 men, nine women; mean age, 61.7 ± 20.5 years; mean heart rate, 74.6 ± 2.8 bpm) with significant stenosis at CCTA (lumen diameter reduction >50%), FFR was performed after CCTA, as a reference standard for the evaluation of myocardial perfusion. FFR value ≤0.75 was considered as positive. CTMPI and CCTA were read by two experienced radiologists with consensus, respectively.

RESULTS

The effective radiation dose of adenosine-stress single-scan CTMPI was 4.63 ± 2.57 mSv. Compared with FFR, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) for identifying significant coronary stenoses were 93.1%, 82.7%, 75.0%, and 95.6%, respectively, on CCTA and 93.1%, 90.3%, 84.4%, and 95.9%, respectively, on CTMPI. On combined CCTA and CTMPI, sensitivity, specificity, PPV, and NPV were 93.1%, 94.2%, 90.0%, and 96.0%, respectively.

CONCLUSION

Adenosine-stress low-dose single scan CTMPI using a 128-slice dual-source CT can provide complementary information on the hemodynamical significance of coronary artery stenosis as well as anatomical information of coronary arteries.