Effect of the respiratory motion of pulmonary nodules on CT-guided percutaneous transthoracic needle biopsy.

BACKGROUND: Computed tomography (CT)-guided percutaneous transthoracic needle biopsy (PTNB) is highly affected by respiratory motion; however, respiratory motion of target nodule during the PTNB and its effect on CT-guided lung biopsy have not been studied. PURPOSE: To investigate the effect of the respiratory motion of pulmonary nodules on CT-guided PTNB. MATERIAL AND METHODS: We retrospectively reviewed the procedural CT scans of 426 pulmonary nodules that underwent PTNB during quiet breathing. Maximal and average respiratory motions were measured using the difference of table position of the targeted nodule between multiple procedural scans. Diagnostic performance, complications, and technical factors of PTNB in nodules with large motion (maximal motion >1 cm) were compared with those in nodules with small motion (≤1 cm). RESULTS: The mean maximal and average respiratory motions between tidal volume breathing were 5.4 ± 4.4 and 2.7 ± 2.6 mm, respectively. Sensitivity and accuracy were 93.1% and 96.1% in nodules with large motion, compared with 94.7% and 95.9% in nodules with small motion, respectively. Respiratory targeting (P < 0.001), needle modulation (P < 0.001), motion artifact of target (P < 0.001), target disappearance from scans (P < 0.001), and number of performed CT scans (P < 0.001) were significantly higher in the large motion group, with no significant difference in radiation dose and complications between the groups. CONCLUSION: The respiratory motion of pulmonary nodules during CT-guided PTNB may cause technical difficulties but does not affect diagnostic performance nor complications associated with PTNB.

Is Free Breathing Possible During Computed Tomography-Guided Percutaneous Transthoracic Lung Biopsy? The Clinical Experience in 585 Cases.

OBJECTIVE: The aim of the study was to retrospectively evaluate the safety and accuracy of computed tomography (CT)-guided percutaneous transthoracic needle biopsy (PTNB) of lung lesions during quiet breathing. METHODS: We investigated the diagnostic performance and complication rate of 585 procedures in 563 patients (357 men; mean age, 67.7 years), who underwent CT-guided PTNBs during quiet breathing, aided by a respiratory targeting technique from May 2017 to July 2019. Differences between the cases with and without respiratory targeting were analyzed. Logistic regression analyses were performed to examine the development of pneumothorax and hemoptysis. RESULTS: Percutaneous transthoracic needle biopsy samples were successfully obtained in 574 of 585 procedures (98.1%). Final diagnoses included: 410 malignant cases, 119 benign cases, and 45 indeterminate cases. The sensitivity, specificity, and accuracy of diagnosis were 94.4%, 100%, and 95.7%, respectively. Use of respiratory targeting was associated with younger age (P = 0.004), smaller lesion size (P < 0.001), peripheral location (P = 0.003), shorter distance from the diaphragm (P < 0.001), lower lobe location (P < 0.001), prone position (P = 0.004), and visible motion artifact (P < 0.001). Pneumothorax and hemoptysis rates were 22.9% and 7.9%, respectively. Upon multivariate analysis, emphysema (P = 0.002) was the only independent risk factor for pneumothorax, whereas distance from the pleura greater than 2 cm (P < 0.001), tissue sampling 3 times or more (P = 0.003), and a less experienced operator (P < 0.001) were risk factors for hemoptysis. CONCLUSIONS: Computed tomography-guided PTNB during quiet breathing with respiratory targeting yielded high diagnostic performance with a slightly higher rate of complications. Free-breathing PTNB can be applied in clinical practice, based on lesion location and risk factors for complications.

Usefulness of pointwise encoding time reduction with radial acquisition sequence in subtraction-based magnetic resonance angiography for follow-up of the Neuroform Atlas stent-assisted coil embolization for cerebral aneurysms.

BACKGROUND: Although time-of-flight magnetic resonance angiography (TOF-MRA) is widely used, it has limited usefulness for follow-up after stent-assisted coil embolization. Contrast-enhanced MRA (CE-MRA) and ultrashort echo time MRA have been suggested as alternative methods for visualization after this procedure. PURPOSE: To compare efficacy and usefulness of pointwise encoding time reduction with radial acquisition (PETRA) sequence in subtraction-based MRA (qMRA), TOF-MRA, and CE-MRA during the follow-up after Neuroform Atlas stent-assisted coil embolization for intracranial aneurysms. MATERIAL AND METHODS: This retrospective study included 23 patients with 24 aneurysms who underwent Neuroform Atlas stent-assisted coil embolization for intracranial aneurysms. All patients were evaluated with PETRA qMRA, TOF-MRA, and CE-MRA at the same follow-up session. The flow within stents, occlusion status, and presence of pseudo-stenosis were evaluated; inter-observer and intermodality agreements for the three methods were also graded. RESULTS: The mean score for flow visualization within the stents was significantly higher for PETRA qMRA and CE-MRA than for TOF-MRA (although no significant difference was found between PETRA qMRA and CE-MRA). Good inter-observer agreement was observed for each modality. PETRA qMRA and CE-MRA were more consistent with digital subtraction angiography (DSA) than TOF-MRA for aneurysm occlusion status. The intermodality agreement was better between PETRA qMRA and DSA, and between CE-MRA and DSA, than between DSA and TOF-MRA. Pseudo-stenosis was most frequently observed in TOF-MRA, followed by CE-MRA and PETRA qMRA. CONCLUSION: PETRA qMRA is useful for evaluating the parent artery patency and occlusion status of aneurysms after Neuroform Atlas stent-assisted coil embolization.

Thrombectomy in acute vertebrobasilar occlusion: a single-centre experience.

PURPOSE: Acute vertebrobasilar occlusion (VBO) has a grave clinical course; however, thrombectomy in VBO patients has rarely been reported. We retrospectively evaluated the clinical and radiological outcomes of thrombectomy in VBO patients. METHODS: From March 2010 to December 2017, 38 patients with 40 acute VBOs underwent thrombectomy at our hospital. Thrombectomy was performed using catheter aspiration (n = 11, 26.8%) or a stent retriever (n = 29, 70.7%). RESULTS: Good clinical outcomes (3-month modified Rankin scale (mRS) of 2 or lower) were achieved in 9 cases (22.5%), and successful recanalization (thrombolysis in cerebral infarction (TICI) grade of 2b or 3) was achieved in 35 cases (87.5%). Good clinical outcomes were significantly related to aetiologies other than atherosclerosis (p = 0.020) and lower National Institutes of Health Stroke Scale (NIHSS) scores on admission (p = 0.025). The clinical and radiological outcomes did not differ significantly between catheter aspiration and stent retriever thrombectomy (p = 1.000 and p = 0.603, respectively); however, stent retriever thrombectomy had a shorter procedure time than catheter aspiration (59.7 ± 31.2 vs. 84.5 ± 35.1 min, p = 0.037). CONCLUSION: In our series, good clinical outcomes were associated with a lower NIHSS score on admission and stroke aetiologies other than atherosclerosis. The two thrombectomy modalities showed similar clinical and radiological outcomes. However, stent retrievers seemed to allow more rapid recanalization than catheter aspiration in VBO.

Initial multicentre experience using the neuroform atlas stent for the treatment of un-ruptured saccular cerebral aneurysms.

Purpose: The Neuroform Atlas is a self-expandable and low-profiled stent that is used for aneurysm neck scaffolding and has been recently approved for clinical practice in Korea. We present our initial experiences of endovascular coiling using the Neuroform Atlas stent.Materials and methods: All cerebral aneurysms treated by stent-assisted coiling with a Neuroform atlas stent in two institutions between February and May 2018 were retrospectively evaluated. Fifty-one patients with 55 un-ruptured saccular cerebral aneurysms (mean size: 4.72 ± 1.81 mm, mean neck diameter: 3.82 ± 1.23 mm, mean dome-to-neck ratio: 1.21) were included in our study (40 females, mean age: 59.29 ± 11.96 years). Patient demographics, aneurysm characteristics, initial angiographic post procedural outcomes, and clinical and angiographic follow-up data were analysed.Results: There was one case of procedural failure due to a downward slip during stent deployment. The technical success rate was 98.2% (54/55). A post-procedure control angiogram showed complete occlusion in 27 (50%), residual neck in 16 (29.6%) and residual sac in 11 (20.4%) aneurysms. There were no procedure-related complications. In one case, a symptomatic thromboembolism with left hand grip weakness (grade IV) was observed two days after the procedure and resolved at discharge. The modified Rankin scale score at discharge was 0 in all patients. Angiographic follow-up data at a mean of 4.8 months were available for 51/54 (94.4%) aneurysms. Among them, 27 aneurysms (52.9%) were stable, 20 aneurysms (39.2%) showed progressive occlusion and 4 aneurysms showed an increased modified Raymond Roy occlusion classification score (only one of these patients was included in the recanalization criteria).Conclusion: Our findings suggest the Neuroform Atlas stent can be useful for the coiling of cerebral aneurysms without significant complications regardless of aneurysm location.

Dual-energy CT angiography-derived virtual non-contrast images for follow-up of patients with surgically clipped aneurysms: a retrospective study.

PURPOSE: To evaluate the diagnostic performance, image quality, artifacts, and radiation doses of virtual non-contrast (VNC) images, relative to true non-contrast (TNC) images, in patients with surgically clipped aneurysms. METHODS: Seventy-six patients who underwent unenhanced computed tomography (CT) and dual-energy (DE)-CT angiography after surgical clipping of 85 intracranial aneurysms were included in the study. Diagnostic performances of VNC and TNC images were compared with respect to sensitivity, specificity, and positive and negative predictive values. The results of quantitative and qualitative analyses were compared between VNC and TNC images. Radiation doses were also compared between VNC and TNC images. RESULTS: Diagnostic performance of VNC images was lower than that of TNC images; however, addition of contrast-enhanced images improved diagnostic performance. Image noise and mean attenuation of VNC images were significantly higher than those of TNC images in the centrum semiovale, cerebellum, and pons. The quality of VNC images was excellent or sufficient (85.5% for observer 1, 85.5% for observer 2), and complete acceptance of VNC images was achieved in 64.5% for observer 1 and in 71.0% for observer 2; however, the addition of contrast-enhanced images increased the level of acceptance (92.0% for observer 1, 90.9% for observer 2). Clip artifacts were significantly lower in VNC images than in TNC images. CT dose index, dose-length product, and effective dose were significantly lower without TNC images. CONCLUSION: VNC images showed lower diagnostic performance and image quality, and higher image noise than TNC images; however, VNC images could reduce clip artifacts and radiation doses.

Utility of routine ultrasonography follow-up after total thyroidectomy in patients with papillary thyroid carcinoma: a single-center study.

BACKGROUND: This study aimed to assess the appropriate number of sessions and interval of routine follow-up ultrasonography (US) in patients who underwent total thyroidectomy for papillary thyroid carcinoma (PTC). METHODS: Between January 2008 and December 2009, 569 patients underwent total thyroidectomy for PTC. Of the 569 patients, 44 were excluded from the study because of no US follow-up data for the neck (n = 43) or owing to indeterminate tumor recurrence/persistence (n = 1). The follow-up US for all the patients was performed by a single radiologist. Based on the cytohistopathological results, tumor recurrence/persistence was determined. RESULTS: In the 525 patients, the mean interval to the last follow-up US was 54.7 months, and the mean number of follow-up US sessions was 4.4. Of the 525 patients, 31 (5.9%) showed nodal (n = 30) and non-nodal (n = 1) tumor recurrence/persistence. Patient age and N stage were independently associated with tumor recurrence/persistence. Among patients showing tumor recurrence/persistence after total thyroidectomy, the time at first detection of suspicious US findings on follow-up US was ≤8 months in 2 patients, between 10 and 23 months in 21, and ≥ 25 months in 8. In a receiver operating characteristic curve analysis, the number of sessions and interval of the provided follow-up US were inappropriate for the detection of tumor recurrence/persistence. CONCLUSIONS: For the detection of tumor recurrence/persistence after total thyroidectomy in PTC patients, routine US follow-up with a 1- or 2-year interval may be excessive.

Endovascular coiling of proximal middle cerebral artery aneurysms: is it safe and durable?

BACKGROUND: Proximal middle cerebral artery (M1 segment) aneurysms are relatively deeply located in neighboring lenticulostriate arteries, which make them unsuitable for microsurgery. We aimed to investigate the clinical and radiological outcomes of endovascular coiling of M1 segment aneurysms. METHODS: Between January 2003 and December 2014, we retrospectively reviewed the medical records of 52 patients (52 aneurysms) from four institutions who underwent endovascular coiling of M1 segment aneurysms. Patients who underwent clinical and radiologic follow-up for more than a year after the procedure were evaluated. RESULTS: The aneurysms were located in the early frontal branch, early temporal branch, and lenticulostriate artery in 28, 15, and nine patients, respectively. Endovascular coiling was achieved in 51 cases and failed in one case. Of these 51 cases, 46 (90.2%) and five (9.8%) were non-ruptured and ruptured aneurysms, respectively. Initial angiographic results revealed complete occlusion in 26 (51.0%), residual neck in 16 (31.4%), and residual sac in nine (17.6%) cases. One failed case had a symptomatic procedural complication of thromboembolism. However, there was no permanent morbidity or mortality. Two major recanalization cases (3.9%) were retreated by endovascular coiling. On multivariable logistic regression analysis, aneurysmal recurrence was significantly related to aneurysm height (OR, 1.887; 95% CI, 1.107 to 3.217; p = 0.020), width (OR, 1.836; CI, 1.127 to 2.992; p = 0.015), and neck (OR, 4.017; CI, 1.220 to 13.232, p = 0.022). CONCLUSION: Endovascular coiling of M1 segment aneurysms appeared to be a feasible treatment option with a relatively low-retreatment rate. Aneurysm size was statistically significantly associated with recurrence.

Congenital absence of the internal carotid artery with a persistent primitive trigeminal artery as a collateral pathway: a report of an anatomic variation.

Congenital absence of the internal carotid artery (ICA) is rare, and patients with such a condition are often asymptomatic throughout their lifetime, because of sufficient collateral circulation. Collateral flow is provided via various channels; however, the role of persistent embryonic vessels under conditions in which the ICA is absent or occluded is unknown. We report a rare case of congenital absence of the left ICA and describe the collateral pathway consisting of a persistent trigeminal artery.

Persistent trigeminal artery variant terminating in the posterior inferior cerebellar artery: a case report.

Persistent trigeminal artery (PTA) is a rare cerebrovascular variation of remnant fetal carotid-vertebrobasilar anastomoses. The PTA variant terminates in the cerebellar artery with no direct connection to the basilar artery. We present a rare case of a PTA variant that terminated directly into the ipsilateral posterior inferior cerebellar artery.

Computed Tomography Features of Benign and Malignant Calcified Thyroid Nodules: A Single-Center Study.

OBJECTIVE: No previous studies have investigated thyroid calcification on computed tomography (CT) quantitatively by using Hounsfield unit (HU) values. This study aimed to analyze quantitative HU values of thyroid calcification on preoperative neck CT and to assess the characteristics of benign and malignant calcified thyroid nodules (CTNs). MATERIALS AND METHODS: Two hundred twenty patients who underwent neck CT before thyroid surgery from January 2015 to June 2016 were included. On soft-tissue window CT images, CTNs with calcified components of 3 mm or larger in minimum diameter were included in this study. The HU values and types of CTNs were determined and analyzed. RESULTS: Of 61 CTNs in 49 patients, there were 42 malignant nodules and 19 benign nodules. The mean largest diameter of the calcified component was 5.3 (2.5) mm (range, 3.1-17.1 mm). A statistically significant difference was observed in the HU values of calcified portions between benign and malignant CTNs, whereas there was no significant difference in patient age or sex or in the size, location, or type of each CTN. Of the 8 CTNs with pure calcification, 3 exhibited a honeycomb pattern on bone window CT images, and these 3 CTNs were all diagnosed as papillary thyroid carcinoma on histopathological examination. CONCLUSIONS: Hounsfield unit values of CTNs may be helpful for differentiating malignancy from benignity.

Impact of Respiratory Phase during Pleural Puncture on Complications in CT-Guided Percutaneous Lung Biopsy.

Purpose: This study investigated whether the respiratory phase during pleural puncture in CT-guided percutaneous transthoracic needle biopsy (PTNB) affects complications. Materials and Methods: We conducted a retrospective review of 477 lung biopsy CT scans performed during free breathing. The respiratory phases during pleural puncture were determined based on the table position of the targeted nodule using CT scans obtained during free breathing. We compared the rates of complications among the inspiratory, mid-, and expiratory respiratory phases. Logistic regression analysis was performed to control confounding factors associated with pneumothorax. Results: Among the 477 procedures, pleural puncture was performed during the expiratory phase in 227 (47.6%), during the mid-phase in 108 (22.6%), and during the inspiratory phase in 142 (29.8%). The incidence of pneumothorax was significantly lower in the expiratory puncture group (40/227, 17.6%; p = 0.035) and significantly higher in the mid-phase puncture group (31/108, 28.7%; p = 0.048). After controlling for confounding factors, expiratory-phase puncture was found to be an independent protective factor against pneumothorax (odds ratio = 0.571; 95% confidence interval = 0.360-0.906; p = 0.017). Conclusion: Our findings suggest that pleural puncture during the expiratory phase may reduce the risk of pneumothorax during image guided PTNB.

Gerstmann-Sträussler-Scheinker Disease: A Case Report.

Gerstmann-Sträussler-Scheinker (GSS) disease is a rare hereditary prion disease which is clinically characterized by a progressive cerebellar ataxia followed by cognitive impairment. We report a rare case of GSS disease in a 39-year-old male patient who complained of a progressive gait disturbance followed by dysarthria with cognitive impairment, after five months from the onset of initial symptom. His brain MRI scan revealed multifocal symmetric diffusion restricted lesions with T2/FLAIR hyperintensities in bilateral cerebral cortices, basal ganglia, and thalami. His family members also manifested similar symptoms in their 40-50s, suggesting the possibility of a genetic disease. Finally, he was genetically diagnosed with GSS disease by real-time quaking-induced conversion and prion protein (PRNP) gene sequencing test.

Correlation between contrast leakage period of procedural rupture and clinical outcomes in endovascular coiling for cerebral aneurysms.

OBJECTIVE: Intraprocedural rupture (IPR) is a fatal complication of endovascular coiling for cerebral aneurysms. We hypothesized that contrast leakage period may be related to poor clinical outcomes. This study aimed to retrospectively evaluate the relationship between clinical outcomes and contrast leakage period. METHODS: Data from patients with cerebral aneurysms treated via endovascular coiling between January 2010 and October 2018 were retrospectively assessed. The enrolled patient's demographic data, the aneurysm related findings, endovascular treatment and IPR related findings, rescue treatment, and clinical outcome were analyzed. RESULTS: In total, 2,859 cerebral aneurysms were treated using endovascular coiling during the study period, with IPR occurring in 18 (0.63 %). IPR occurred during initial frame coiling (n=4), coil packing (n=5), stent deployment (n=7), ballooning (n=1), and microcatheter removal after coiling (n=1). Tear sites included the dome (n=14) and neck (n=4). All IPRs were controlled and treated with coil packing, with or without stenting. Flow arrest of the proximal balloon was not observed. Temporary focal neurological deficits developed in two patients (11.1%). At clinical follow-up, 14 patients were classified as modified Rankin Scale (mRS) 0, three as mRS 2, and one as mRS 4. The mean contrast leakage period of IPR was 11.2 min (range: 1-31 min). Cerebral aneurysms with IPR were divided into late (n=9, mean time: 17.11 min) and early (n=9, mean time: 5.22 min) control groups based on the criteria of 10 min of contrast leakage period. No significant between-group differences regarding clinical outcomes were observed after IPR (p=1). CONCLUSIONS: In our series, all patients with IPR were controlled with further coil packing or stenting without proximal balloon occlusion within 31 min of contrast leakage. There was no difference in clinical outcomes when the long contrast leakage period group and short contrast leakage period group were compared.

Persistent Primitive Olfactory Artery Type 4 with Fusiform Aneurysm: A Case Report.

The persistent primitive olfactory artery (PPOA) is a rare variant of the anterior cerebral artery, first reported in 1979. It reportedly has a high correlation with the development of aneurysms, owing to the hemodynamic stress induced by the structural characteristics of the hairpin turn. Herein, we present a rare case of PPOA type 4 with a fusiform aneurysm at the hairpin turn segment in a 46-year-old female with occasional headaches. Time-of-flight MR angiography and transfemoral cerebral angiography revealed an unusual branch arising from the left A1 segment, running anteromedially along the ipsilateral olfactory tract, and turning the hairpin posterior to the olfactory bulb. This branch continued into the left accessory middle cerebral artery, and a fusiform aneurysm was observed at the hairpin segment. No further treatment was performed, and follow-up imaging was recommended. Nevertheless, it is essential to recognize and diagnose these rare variations.

The efficacy and efficiency of percutaneous lidocaine injection for minimizing the carotid reflex in carotid artery stenting: A single-center retrospective study.

Objective: To assess whether local anesthetic infiltration could minimize the carotid baroreceptor reflex (CBR) which has an incidence after carotid artery stenting (CAS) that varies from 29% to 51%. Methods: This retrospective single-center study included 51 patients (mean age, 70.47 years) who underwent CAS for carotid stenosis. The groups included patients who underwent CAS for asymptomatic ischemic stroke (n=41) or symptomatic disease (n=10). Preprocedural percutaneous lidocaine injections (PPLIs) were administered to 70.6% and 5.9% of patients who underwent elective CAS and emergency CAS, respectively. Results: Among patients who received PPLIs, the mean degree of stenosis was 80.5% (95% confidence interval [CI]: ±10.74, 51-98%). The mean distance from the common carotid artery bifurcation to the most stenotic lesion (CSD) was 8.3 mm (95% CI: ±0.97, 6.3-10.2 mm); the mean angle between the internal carotid artery and common carotid artery (CCA) trunk (IAG) was 65.6° (95% CI: ±2.39, 61-70°). Among patients who did not receive PPLIs, the mean degree of stenosis was 84.0% (95% CI: ±8.96, 70-99%). The mean CSD was 5.9 mm (95% CI: ±1.83, 1.9-9.9 mm); the mean IAG was 60.4° (95% CI: ±4.41, 51-70°). The procedure time was longer in the PPLI group than in the no PPLI group (28.19 [n=39] vs. 18.88 [n=12] days) (P=0.057); the length of intensive care unit stay was shorter in the PPLI group (20.01 [n=36] vs. 28.10 [n=5] days) (P=0.132). Conclusions: Targeted PPLI administration to the carotid bulb decreased aberrant heart rates and blood pressure changes induced by carotid stent deployment and balloon inflation. As CBR sensitivity increases with decreasing distance to the stenotic lesion from the CCA bifurcation, PPLIs may help stabilize patients during procedures for stenotic lesions closer to the CCA.

Usefulness of Pointwise Encoding Time Reduction with Radial Acquisition-Magnetic Resonance Angiography after Endovascular Treatment for Intracranial Aneurysms.

PURPOSE: Imaging follow-up after endovascular treatment is important; however, time-of-flight magnetic resonance angiography (TOF-MRA) has limitations associated with magnetic susceptibility and radiofrequency shielding caused by the stent and coils. We evaluated the diagnostic performance of pointwise encoding time reduction with radial acquisition (PETRA)-MRA after endovascular treatment for intracranial aneurysms. MATERIAL AND METHODS: A total of 186 patients with 211 aneurysms who underwent both pointwise encoding time reduction with radial acquisition- and time-of-flight magnetic resonance angiography in the same imaging session for follow-up after endovascular treatment. We subjectively graded the overall image quality, visualization of treated sites, and occlusion status. RESULTS: Although the overall image quality scores of pointwise encoding time reduction with radial acquisition-magnetic resonance angiography were significantly lower than those of time-of-flight magnetic resonance angiography for both observers (4.04 ± 0.81 vs. 4.85 ± 0.35 [observer 1], 4.60 ± 0.69 vs. 4.94 ± 0.24 [observer 2]) (both P < .001), the visibility of treated sites using pointwise encoding time reduction with radial acquisition-magnetic resonance angiography was significantly better than that of time-of-flight magnetic resonance angiography overall (4.27 ± 0.97 vs. 3.42 ± 1.01; P < .001), in the distal internal carotid artery (4.46 ± 0.79 vs. 3.40 ± 1.00; P < .001), and in the middle cerebral artery (4.19 ± 0.93 vs. 3.08 ± 0.53, P = 0.007). Pointwise encoding time reduction with radial acquisition-magnetic resonance angiography showed a higher area under the curve than time-of-flight magnetic resonance angiography for the evaluation of treated aneurysm occlusion, except for posterior circulation aneurysms. CONCLUSIONS: Pointwise encoding time reduction with radial acquisition-magnetic resonance angiography showed better visualization of treated sites and better diagnostic performance than time-of-flight magnetic resonance angiography for anterior circulation aneurysms. However, Pointwise encoding time reduction with radial acquisition-magnetic resonance angiography showed limitations in the follow-up evaluation of posterior circulation aneurysms.

Detection of pericardial flow in black blood-prepared T2 HASTE sequence imaging: Differentiation between pericardial diverticulum and cyst.

Pericardial diverticulum is a focal herniation of the pericardium. It is differentiated from a pericardial cyst by the presence of communication with the pericardial cavity. Radiological differentiation between the diverticulum and cyst via computed tomography is difficult unless changes in size are identified with different body positions in additional scans. Herein we describe a case of pericardial diverticulum that was successfully diagnosed via the detection of internal pericardial flow in black blood-prepared T2 half-Fourier acquisition single-shot turbo spin-echo magnetic resonance imaging. Detection of a flow void in the pericardial sac may be a definitive magnetic resonance imaging finding in the diagnosis of pericardial diverticulum.

Isolated Intracranial Rosai-Dorfman Disease Mimicking Meningioma: A Case Report.

Rosai-Dorfman Disease (RDD) is a rare lymphoproliferative disease, and the occurrence of isolated intracranial RDD is extremely rare. Most cases of intracranial RDDs present as dural masses showing homogenous enhancement on MRI, which makes it difficult to differentiate these masses from meningiomas before surgery unless massive cervical lymphadenopathy is observed. We herein report a rare case of isolated intracranial RDD in a 65-year-old male. Brain MRI revealed a well-defined enhancing mass-like lesion involving the right frontal convexity and subtle diffusion restriction. However, only a subtle blush was observed on the preoperative cerebral angiogram. Although instances of isolated intracranial RDD are rare, it should be considered as a potential differential diagnosis when a dural mass with hypovascularity is visualized on the cerebral angiogram.