Endovascular occlusion of an aortic coarctation after thoracic endovascular aortic repair of an anastomotic aneurysm

A 58-year-old man with a history of aortic and mitral mechanical valve replacement was referred to our hospital for symptomatic chronic heart failure. In 1988, he had undergone open surgical correction of an isthmic aortic coarctation (CoA), with the creation of an extra-anatomic bypass from the left subclavian artery to the descending thoracic aorta. The following findings were found: severe mitral valve failure with perivalvular leakage, severe aortic valve stenosis, pulmonary hypertension, distal anastomotic aneurysm with the apparent occlusion of the CoA. A thoracic endovascular aneurysm repair was performed. A postoperative high-pressure leak with no evident signs of ineffective sealing was observed. Computed tomography angiography (CTA) 3D reconstruction demonstrated the recanalization of the CoA. A second procedure was planned. The CoA was anterogradely cannulated. Three coils were deployed into the aneurysmal sac, followed by a vascular plug, positioned on the coarctation conduit, but it failed to anchor and dislocated into the sac. A second plug was deployed, but it also partially dislocated. Finally, a patent foramen ovale occluder device was deployed to occlude the communication. The final angiogram showed the complete occlusion of the coarctation and correction of the leak, which was confirmed by a 6-month post-operative CTA.

For patients who undergo surgical repair of aortic coarctation (CoA), lifelong follow-up should be mandatory, due to the risk of long-term complications. Up-to-date guidelines suggest surgical correction of the CoA in infants, in order to maintain the aortic flow, while an endovascular approach is preferred in adults (1, 2). We describe a case of CoA catheter-based occlusion with a patent foramen ovale (PFO) closure device.A 58-year-old man with a history of aortic and mitral mechanical valve replacement was referred to our hospital for symptomatic chronic heart failure. In 1988, he had undergone open surgical correction of an isthmic aortic coarctation, with the creation of an extra-anatomic bypass from the left subclavian artery to the descending thoracic aorta.Transesophageal and transthoracic ultrasound evaluations showed severe mitral valve failure with perivalvular leakage, severe aortic valve stenosis, and pulmonary hypertension. Computed tomography angiography (CTA) confirmed the aforementioned findings and showed enlargement of the anastomotic aneurysm (from 47 mm to 58 mm) with the apparent occlusion of the CoA (Fig. 1a). Progressive worsening of the symptoms required prompt surgical substitution of the mechanic valves. However, after consultation with the cardiac surgery team, it was decided to postpone the procedure to perform thoracic endovascular aneurysm repair (TEVAR) first, in order to reduce the risk of aneurysm rupture during open heart surgery.Open in a separate windowFigure 1. a, bComputed tomography angiography (CTA) image (a) confirms enlargement of the anastomotic aneurysm with apparent occlusion of the aortic coarctation. Standard thoracic endovascular aortic repair was performed with a Conformable C-TAG (b, 31/150 mm, W. L. Gore and Associates). LSA, left subclavian artery; DTA, descending thoracic aorta.     

MRI in local staging of rectal cancer: an update

Preoperative imaging for staging of rectal cancer has become an important aspect of current approach to rectal cancer management, because it helps to select suitable patients for neoadjuvant chemoradiotherapy and determine the appropriate surgical technique. Imaging modalities such as endoscopic ultrasonography, computed tomography, and magnetic resonance imaging (MRI) play an important role in assessing the depth of tumor penetration, lymph node involvement, mesorectal fascia and anal sphincter invasion, and presence of distant metastatic diseases. Currently, there is no consensus on a preferred imaging technique for preoperative staging of rectal cancer. However, high-resolution phased-array MRI is recommended as a standard imaging modality for preoperative local staging of rectal cancer, with excellent soft tissue contrast, multiplanar capability, and absence of ionizing radiation. This review will mainly focus on the role of MRI in preoperative local staging of rectal cancer and discuss recent advancements in MRI technique such as diffusion-weighted imaging and dynamic contrast-enhanced MRI.Colorectal cancer is the second most common cancer in women and the third most common cancer in men with 570 100 and 663 600 estimated new cases per year worldwide, respectively (1). Rectal cancer accounts for approximately 42% of colorectal cancers with 45 000 estimated new cases per year in the United States (2). Prognosis of rectal cancer is determined by depth of invasion, number of involved lymph nodes, and involvement of circumferential resection margin. Management of rectal cancer has evolved over the years with preoperative imaging playing an increasingly prominent role. Initial strategy of clinical diagnosis followed by surgery and postoperative chemotherapy had a high local recurrence rate (27%) and poor survival (48% 5-year survival) (3). Later studies showed that neoadjuvant chemoradiation improves survival and decreases local recurrence rates significantly (4). In addition, it reduces tumor size, facilitates curative resection (5), and may enable sphincter sparing surgery in cancers close to the anorectal junction (6). Neoadjuvant chemoradiotherapy is not indicated in stage I tumors (confined to rectal wall with no nodal involvement), but is recommended for stage II (extends beyond the rectal wall, no nodal involvement) and stage III tumors (regional lymph node involvement). Therefore, in order to avoid unnecessary chemoradiation in stage I cancers, a reliable imaging modality is crucial to precisely define depth of invasion and to identify lymph node involvement (7). Current approach in the management of rectal cancer includes preoperative staging with different imaging modalities followed by neoadjuvant chemoradiotherapy (for stage II/III cancers). This approach has lowered the local recurrence rate (11%) and improved survival (58% 5-year survival) (3).Preoperative imaging for rectal cancer staging is also useful to determine which surgical technique would be more appropriate: recently-developed local excision method of transanal resection or traditional radical resections such as low anterior resection or abdominoperineal resection. Physical examination, endoscopic evaluation, and imaging modalities are used for preoperative staging of rectal cancer. Ideal imaging modality should accurately assess the depth of tumor penetration (T), lymph node involvement (N), presence of distant metastatic disease (M), mesorectal fascia involvement, and anal sphincter involvement. Currently, there is no consensus on a preferred imaging technique for preoperative staging of rectal cancer.Endoscopic ultrasonography, one of the oldest and most widely used imaging modalities, is reported to assess T staging with 67%–97% accuracy and nodal involvement with 64%–88% accuracy (8–11). Although it has a role in staging of early cancers confined to the wall of the rectum, endoscopic ultrasonography may not assess deeper or higher nodes in the mesorectum and can misinterpret inflammatory or fibrotic changes as metastasis (12). Its value is also limited in the evaluation of near-obstructing tumors, tumors in the upper rectum, and mesorectal fascia involvement (12, 13).Computed tomography (CT) is commonly used in rectal cancer because of its ability to assess entire pelvic anatomy and presence or absence of distant metastasis. However, CT has limited soft tissue contrast for local staging. A meta-analysis of 83 studies showed that CT has 73% accuracy for T staging and 22%–73% accuracy for nodal staging (14). In a recent study, Sinha et al. (15) showed T stage accuracy of 87.1% and N stage accuracy of 87.1%. Although newer multidetector CT technology with multiplanar reformations has improved the accuracy, soft tissue resolution of CT is still inadequate to evaluate early rectal cancers.On the other hand, high-resolution phased-array MRI is recommended as a standard imaging modality for pre-operative local staging of rectal cancer, with excellent soft tissue contrast, functional imaging ability, and multi-planar capability (Figs. 1 and ​and2).2). With these inherent proprieties, MRI fills a gap in clinical practice and helps accurate local staging of rectal cancer prior to management decisions. This review will mainly focus on the role of MRI in preoperative local staging of rectal cancer and discuss recent advancements in MRI technique.Open in a separate windowFigure 1. a, b.Axial (a) and coronal (b) fast spin-echo T2-weighted MR images obtained with a phased-array coil on a 3.0 T magnet show the normal anatomy of the pelvis. The rectum (a, arrowhead) is distended with water. Note uterus (a, arrow), and oval-shaped fatty-centered left iliac node (a, curved arrow), which is likely reactive. The iliococcigeal part of the levator ani muscle (b, arrows) extends from the pelvic sidewalls to the anus and joins with the puborectalis muscle (b, arrowheads) to form the external sphincter of the anus (b, curved arrow).Open in a separate windowFigure 2.Axial T2-weighted MR image obtained with an endorectal coil shows the layers of the rectum. Hyperintense submucosa (curved arrows) is surrounded by hypointense muscularis propria (arrows). The mucosa cannot be differentiated from the submucosa, and both layers appear as a single hyperintense layer. Note the levator ani muscle (curved arrows).     

The potential role of modern US in the follow-up of patients with retroperitoneal fibrosis

PURPOSE

We aimed to evaluate a standardized ultrasonography (US) algorithm for the visualization of pathologic para-aortic tissue in retroperitoneal fibrosis (RPF).

MATERIALS AND METHODS

Thirty-five patients with lumbar RPF of typical extent, as determined by abdominal magnetic resonance imaging, were included. Examinations were conducted using standardized abdominal US with axial sections obtained at the levels of the renal arteries, aortic bifurcation, and both common iliac arteries. Imaging of each section was acquired with fundamental B-mode (US) and tissue harmonic imaging, respectively. In addition, we examined RPF visualized using extended field-of-view US.

RESULTS

Tissue harmonic imaging adequately visualized RPF of typical extent in 33 patients (94.2%). Excellent and good visualization with mild artifacts were achieved in 25 (71.4%) and six (17.1%) patients, respectively. When RPF spread along the iliac arteries, excellent visualization was achieved in 38.7% for the left side and 34.5% for the right side. There were significantly fewer diagnostic examinations for the right iliac (27.6%) than for the left one (9.7%) (P = 0.016). Overall, harmonic imaging achieved significantly better visualization than fundamental B-Mode (P < 0.001).

CONCLUSION

We described the first systematic evaluation of RPF visualization by modern US techniques. The best imaging quality was found in the typical RPF location, at the level of the aortic bifurcation. These results advocate for the presented US algorithm as an efficient follow-up alternative to cross-sectional imaging in RPF patients.Chronic periaortitis or retroperitoneal fibrosis (RPF) is a rare fibrosing disease that affects para-aortic tissues (1–3). It typically presents as a proliferating lumbar process surrounding the ureters and retroperitoneal vascular structures (Fig. 1) (2, 4). Sporadic, atypical manifestations in pelvic and mesenteric regions are also possible (5).Open in a separate windowFigure 1. a–c.Typical extent of the retroperitoneal fibrosis surrounding the infrarenal aorta (a). Spreading of the fibrosis to the renal arteries and along the common iliac arteries (b). Standardized US examination with four transverse sections (c). AO, aorta; AIC, common iliac artery; RA, renal artery; RPF, retroperitoneal fibrosis.Magnetic resonance imaging (MRI) allows precise evaluation of the extent and complications (6). RPF presents as hypointense (often isointense to striated muscle) plaques in native T1-weighted magnetic resonance (MR) images with significant gadolinium contrast enhancement of active and untreated retroperitoneal fibrosis (7–9).Ultrasonography (US) is primarily used in patients with RPF for a rapid and practical diagnosis of consecutive hydronephrosis (6). RPF presents as a smooth-bordered mass with either an echo-poor or echo-free signal (10, 11). Two studies in the 1980s indicated that US revealed only a poor overall sensitivity in the detection of RPF (12, 13). Feinstein et al. (14) reported that only 25% of affected patients with computed tomography (CT)-mediated diagnosis of RPF showed corresponding ultrasonographic abnormalities. Since that time the quality of US scanners has improved dramatically, and modern techniques, such as tissue harmonic imaging (THI) and extended field-of-view US, have significant advantages for routine clinical diagnosis (15–17). Today, US has established itself as an effective and cost-efficient imaging method for the screening and follow-up of infrarenal aortic aneurysms (18, 19). US, however, is not used routinely for RPF follow-up, nor has a systematic evaluation of modern ultrasonographic methods been available to date.The aim of the present study was to evaluate the potential role of modern ultrasonographic techniques for the visualization of fibrous tissue in patients with prediagnosed RPF.     

Increased x-ray attenuation in malignant vs. benign mediastinal nodes in an orthotopic model of lung cancer

PURPOSE

Staging of lung cancer is typically performed with fluorodeoxyglucose-positron emission tomography-computed tomography (FDG-PET/CT); however, false positive PET scans can occur due to inflammatory disease. The CT scan is used for anatomic registration and attenuation correction. Herein, we evaluated x-ray attenuation (XRA) within nodes on CT and correlated this with the presence of malignancy in an orthotopic lung cancer model in rats.

METHODS

1×10⁶ NCI-H460 cells were injected transthoracically in six National Institutes of Health nude rats and six animals served as controls. After two weeks, animals were sacrificed; lymph nodes were extracted and scanned with a micro-CT to determine their XRA prior to histologic analysis.

RESULTS

Median CT density in malignant lymph nodes (n=20) was significantly higher than benign lymph nodes (n=12; P = 0.018). Short-axis diameter of metastatic lymph nodes was significantly different than benign nodes (3.4 mm vs. 2.4 mm; P = 0.025). Area under the curve for malignancy was higher for density-based lymph node analysis compared with size measurements (0.87 vs. 0.7).

CONCLUSION

XRA of metastatic mediastinal lymph nodes is significantly higher than benign nodes in this lung cancer model. This suggests that information on nodal density may be useful when used in combination with the results of FDG-PET in determining the likelihood of malignant adenopathy.Lung cancer is the leading cause of cancer deaths in the United States and Europe (1). Choice of therapy and prognosis is determined by the stage at which lung cancer is detected. Mediastinal nodal involvement is a significant negative prognostic sign and portends a shorter time to progression (2). Fluorodeoxyglucose-positron emission tomography-computed tomography (FDG-PET/CT) has emerged as the leading noninvasive staging method as both primary tumor and mediastinal nodes can be assessed (2, 3). Precise mediastinal N-staging is mandatory since patients with contralateral or multiregional mediastinal lymph node metastases are often excluded from primary surgery (4). The PET component of the FDG-PET/CT examination is typically assessed by measuring the maximum standardized uptake value (SUV_max) in the primary tumor and nodes. However, the FDG-PET component is sometimes equivocal due to false positive uptake in inflammatory nodes (5). The CT component is typically assessed using Response Evaluation Criteria In Solid Tumors (RECIST 1.1) criteria in the primary and nodes, and it is based on the node’s short-axis diameter (3). However, size changes are notoriously unreliable in assessing disease status. Therefore, staging often requires additional invasive methods such as transbronchial biopsy or mediastinoscopy for histologic verification (6), especially in patients that might benefit from primary surgery.Previous reports have suggested that nodes exhibit increases in x-ray attenuation (XRA) density when they become malignant due to replacement of the fatty nodal hilum with cancer cells (5). For instance, malignant lymph nodes obtained from patients with breast cancer showed increased density on grating-based phase-contrast x-ray tomography (7–10). However, this observation is not routinely incorporated into clinical interpretation of PET/CT despite the ready availability of such information. In order to further investigate potential density changes in metastatic and nonmetastatic mediastinal and hilar lymph nodes, we utilized an orthotopic lung cancer model in nude rats (11), which included ex vivo micro-CT XRA of extracted lymph nodes two weeks after transthoracic tumor cell implantation (Fig. 1). Findings were correlated with histology.Open in a separate windowFigure 1Study design with in vivo and ex vivo measurements. Step 1: Transthoracic tumor cell transplantation in the 5th intercostal space. Step 2: Within the first two weeks after transthoracic tumor cell transplantation tumor spreads in mediastinal and hilar lymph nodes (small yellow dots). Primary tumor is seen in the right lower lobe (big yellow dot). Step 3: Micro-CT examination of extracted mediastinal lymph nodes.     

Irreversible electroporation: evolution of a laboratory technique in interventional oncology

Electroporation involves applying electric field pulses to cells, leading to the alteration or destruction of cell membranes. Irreversible electroporation (IRE) creates permanent defects in cell membranes and induces cell death. By directly targeting IRE to tumors, percutaneous nonthermal ablation is possible. The history of IRE, evolution of concepts, theory, biological applications, and clinical data regarding its safety and efficacy are discussed.A number of modalities are available for percutaneous tumor ablation. These methods primarily include thermal techniques, such as cryoablation, radiofrequency, or microwave ablation, which involve cooling or heating the tissue to induce cell death. Because these methods depend on thermal injury, they carry some risk to the adjacent extracellular environment. Consequently, treating tumors adjacent to critical vascular structures is a challenge that potentially limits the aggressiveness of the attempted ablation.In recent years, electroporation has emerged as a new method of tumor ablation. Electroporation, also known as electropermeabilization, involves the application of short pulses of strong electric fields to cells and tissues. External electric fields increase the transmembrane potential, charging the membrane like a capacitor by moving ions from the surrounding solution. Applying electric fields to cells is thought to induce the formation of pores, which are responsible for the permeabilization effect; however, more extensive, irreversible damage from higher fields is used to ablate tumor cells (Fig. 1). By using small electrodes (∼1 mm diameter) placed close to the target and short, repetitive electric field pulses, nonthermal irreversible electroporation (IRE) appears to offer an advantage over other ablation methods that involve tissue heating.Open in a separate windowFigure 1.Cartoon illustration of irreversible electroporation in a liver tumor. The left panel demonstrates a liver containing an ovoid tumor with surrounding two linear irreversible electroporation probes. Magnified view of the tumor reveals movement of the electric current (yellow arrows) across a cell membrane that leads to the breakdown of cell membrane integrity, the loss of cellular gradients, and the death of the cell. The image in the right panel shows an ablated tumor, depicting its preserved adjacent vasculature and ducts.While electroporation has been studied and used for decades in the laboratory and food industry, it has not been applied to the field of interventional oncology until recently. Today, human trials utilizing electroporation to treat a variety of tumors are underway. This review describes the evolution of the technique from the bench to the bedside and highlights the remaining challenges to standardizing its use in tumor ablation.     

Demystifying ABER (ABduction and External Rotation) sequence in shoulder MR arthrography

ABduction and External Rotation (ABER) sequence in magnetic resonance (MR) arthrography of the shoulder is particularly important to better depict abnormal conditions of some glenohumeral joint structures and surrounding tissues by making imaging possible under a stress position relevant to pathologic conditions. Among the structures and tissues better depicted in this position are articular surface of the supraspinatus tendon, anteroinferior portion of the glenoid labrum, and anterior band of the inferior glenohumeral band. Despite these benefits of the ABER sequence, it is either not being used extensively as part of shoulder MR arthrograms or, when utilized, not properly assessed, mostly due to some practical difficulties in setting up the sequence and unfamiliarity with the alignment of structures displayed on MR images. In this technical note, we aimed to explain the ABER sequence planning in a step-by-step manner with emphasis on scout series set-up, and also present an outline of anatomic landmarks seen on ABER images.Magnetic resonance (MR) imaging portion of a routine shoulder MR arthrography exam is performed with the patient lying in supine position on the scanner table with both arms lying alongside the torso, in the same position as a routine shoulder MR imaging exam. An additional sequence with the patient’s arm ABducted and Externally Rotated (i.e., the so-called “ABER view”) has been shown to be useful not only in clarifying equivocal findings, but also in making diagnoses that may not be readily visible on a routine MR arthrography exam (1, 2).Despite the benefits of the ABER sequence, it is either not being used extensively as part of shoulder MR arthrograms or, when utilized, not properly assessed, mostly due to some practical difficulties in setting up the sequence and unfamiliarity with the alignment of structures displayed on MR images. A true ABER position with 90° of abduction and 90° of flexion of the arm (Fig. 1a) is not feasible with closed-bore MR scanners, which constitute the majority. Therefore, the patient usually has to make >90° of abduction to fit into the magnet (Fig. 1b). On one hand it is quite hard for many patients with shoulder problems to assume such a position for prolonged periods. On the other hand, an improperly aligned imaging plane for ABER sequence would be of limited- or no-use, rendering the patient burden futile. It is, therefore, particularly important to take extra steps to make sure the ABER sequence is properly planned.Open in a separate windowFigure 1. a, b.True ABER position (a) as an apprehension (or stress) test for orthopedists entails 90° of abduction and 90° of flexion of the arm at the shoulder. During ABER positioning for MR arthography of the shoulder, the patient usually has to make >90° of abduction of the arm to fit into the magnet (b).In this technical note, we aimed to explain the ABER sequence planning in a step-by-step manner with emphasis on scout series set-up, and also present an outline of anatomic landmarks seen on ABER images.     

Single-stage endovascular treatment in patients with severe extracranial large vessel stenosis and concomitant ipsilateral unruptured intracranial aneurysm

PURPOSE

We aimed to evaluate the safety and effectiveness of single-stage endovascular treatment in patients with severe extracranial large vessel stenosis and concomitant ipsilateral unruptured intracranial aneurysm.

METHODS

Hospital database was screened for patients who underwent single-stage endovascular treatment between February 2008 and June 2013 and seven patients were identified. The procedures included unilateral carotid artery stenting (CAS) (n=4), bilateral CAS (n=2), and proximal left subclavian artery stenting (n=1) along with ipsilateral intracranial aneurysm treatment (n=7). The mean internal carotid artery stenosis was 81.6% (range, 70%–95%), and the subclavian artery stenosis was 90%. All aneurysms were unruptured. The mean aneurysm diameter was 7.7 mm (range, 5–13 mm). The aneurysms were ipsilateral to the internal carotid artery stenosis (internal carotid artery aneurysm) in five patients, and in the anterior communicating artery in one patient. The patient with subclavian artery stenosis had a fenestration aneurysm in the proximal basilar artery. Stenting of the extracranial large vessel stenosis was performed before aneurysm treatment in all patients. In two patients who underwent bilateral CAS, the contralateral carotid artery stenosis, which had no aneurysm distally, was treated initially.

RESULTS

There were no procedure-related complications or technical failure. The mean clinical follow-up period was 18 months (range, 9–34 months). One patient who underwent unilateral CAS experienced contralateral transient ischemic attack during the clinical follow-up. There was no restenosis on six-month follow-up angiograms, and all aneurysms were adequately occluded.

CONCLUSION

A single-stage procedure appears to be feasible for treatment of patients with severe extracranial large vessel stenosis and concomitant ipsilateral intracranial aneurysm.The concomitance of severe extracranial large vessel stenosis and unruptured ipsilateral distal intracranial aneurysm is often detected incidentally and their management is not clear (1). Although there are many studies in the literature that report different treatment approaches, there is no definite consensus on the management of the concomitant lesions (2–14). Various treatment options have been suggested, such as initial treatment of the aneurysm before revascularization of the stenosis, treating both lesions in the same surgical session and correcting the stenosis without treating the aneurysm (1, 5, 6, 9–11, 14–16). Few studies have reported single-stage endovascular treatment of both lesions as an effective method (17–19). On the other hand, the treatment of each lesion by this technique may lead to procedure-related undesired events such as cerebral ischemia/stroke or aneurysm rupture.In this study, we aimed to present the radiologic and clinical results of seven consecutive patients who underwent single-stage endovascular treatment of severe extracranial large vessel stenosis and concomitant unruptured ipsilateral intracranial aneurysm and discuss the safety and feasibility of this approach. In addition, distinct from the limited number of similar studies in the literature, we present our experience with bilateral carotid artery stenting (CAS) and proximal subclavian artery stenting during single-stage endovascular treatment.     

Risk factors associated with late aneurysmal sac expansion after endovascular abdominal aortic aneurysm repair

PURPOSE

We aimed to identify the risk factors associated with late aneurysmal sac expansion after endovascular abdominal aortic aneurysm repair (EVAR).

METHODS

We retrospectively reviewed contrast-enhanced computed tomography (CT) images of 143 patients who were followed for ≥6 months after EVAR. Sac expansion was defined as an increase in sac diameter of 5 mm relative to the preoperative diameter. Univariate and multivariate analyses were performed to identify associated risk factors for late sac expansion after EVAR from the following variables: age, gender, device, endoleak, antiplatelet therapy, internal iliac artery embolization, and preprocedural variables (aneurysm diameter, proximal neck diameter, proximal neck length, suprarenal neck angulation, and infrarenal neck angulation).

RESULTS

Univariate analysis revealed female gender, endoleak, aneurysm diameter ≥60 mm, suprarenal neck angulation >45°, and infrarenal neck angulation >60° as factors associated with sac expansion. Multivariate analysis revealed endoleak, aneurysm diameter ≥60 mm, and infrarenal neck angulation >60° as independent predictors of sac expansion (P < 0.05, for all).

CONCLUSION

Our results suggest that patients with small abdominal aortic aneurysms (<60 mm) and infrarenal neck angulation ≤60° are more favorable candidates for EVAR. Intraprocedural treatments, such as prophylactic embolization of aortic branches or intrasac embolization, may reduce the risk of sac expansion in patients with larger abdominal aortic aneurysms or greater infrarenal neck angulation.The aim of endovascular abdominal aortic aneurysm repair (EVAR) is to prevent rupture of an abdominal aortic aneurysm (AAA) by depressurizing the aneurysm and excluding it from the systemic circulation using a stent-graft. Aneurysmal sac reduction is a reliable marker for the long-term prognosis after EVAR. Although most aneurysmal sacs shrink after EVAR, some sacs continue to expand. A relationship between aneurysm size and endoleaks was previously reported (1, 2). Most type II endoleaks spontaneously disappear over time, but 10%–25% persist for more than six months after EVAR (3–6). Persistent endoleaks with aneurysmal sac expansion are at high risk of rupture because of the continuously elevated intra-aneurysmal pressure and require a second intervention, such as embolization (7–11). However, it is difficult to predict sac expansion and persistent endoleak before performing EVAR. Although intraoperative intrasac thrombin injection and prophylactic embolization of aortic branches such as the inferior mesenteric artery and lumbar artery are reported to reduce the incidence of type II endoleak, the efficacy and clinical benefit of these procedures in terms of late postoperative aneurysm shrinkage have not been fully evaluated (12–15). Therefore, the purpose of this study was to identify the risk factors associated with late aneurysmal sac expansion after EVAR to determine possible indications for intrasac embolization and prophylactic embolization of aortic branches.     

Clinical applications of PET/MRI: current status and future perspectives

Fully integrated positron emission tomography (PET)/magnetic resonance imaging (MRI) scanners have been available for a few years. Since then, the number of scanner installations and published studies have been growing. While feasibility of integrated PET/MRI has been demonstrated for many clinical and preclinical imaging applications, now those applications where PET/MRI provides a clear benefit in comparison to the established reference standards need to be identified. The current data show that those particular applications demanding multiparametric imaging capabilities, high soft tissue contrast and/or lower radiation dose seem to benefit from this novel hybrid modality. Promising results have been obtained in whole-body cancer staging in non-small cell lung cancer and multiparametric tumor imaging. Furthermore, integrated PET/MRI appears to have added value in oncologic applications requiring high soft tissue contrast such as assessment of liver metastases of neuroendocrine tumors or prostate cancer imaging. Potential benefit of integrated PET/MRI has also been demonstrated for cardiac (i.e., myocardial viability, cardiac sarcoidosis) and brain (i.e., glioma grading, Alzheimer’s disease) imaging, where MRI is the predominant modality. The lower radiation dose compared to PET/computed tomography will be particularly valuable in the imaging of young patients with potentially curable diseases. However, further clinical studies and technical innovation on scanner hard- and software are needed. Also, agreements on adequate refunding of PET/MRI examinations need to be reached. Finally, the translation of new PET tracers from pre-clinical evaluation into clinical applications is expected to foster the entire field of hybrid PET imaging, including PET/MRI.Both positron emission tomography (PET) and magnetic resonance imaging (MRI) are well-established imaging modalities that have been clinically available for more than 30 years. However, the combination of PET and computed tomography (CT) into PET/CT has heralded a new era of hybrid imaging driven by the rapid ascend of PET/CT and the decline of stand-alone PET. The integration of PET and CT into a hybrid system provided added value that exceeds the sum of its parts, in particular fast and accurate attenuation correction and the combination of anatomical and molecular information.Inspired by the vast success of PET/CT, the combination of PET and MRI was an obvious goal. Therefore initial solutions comprised the software based co-registration and post-hoc fusion (1) of independently acquired PET and MRI data, as well as shared tabletop sequential PET and MRI acquisition (2, 3). While the integration of PET and CT into a hybrid system was challenging but technically feasible, the integration of PET and MRI was considered extremely demanding, if not impossible. Two main technical challenges that had to be solved: in the first place development of a PET insert that is compatible to high magnetic field strengths normally used in MRI, and vice versa development of a magnetic resonance (MR) scanner that guarantees a stable and homogenous magnetic field in the presence of a PET insert. Conventional PET detectors consist of scintillation crystals and photomultipliers, and the latter, being very sensitive to magnetic fields, cannot be used in integrated PET/MRI systems. Hence, one approach was to replace photomultipliers by avalanche photodiodes (APDs), which are insensitive to even strong magnetic fields (4). The scintillation crystals used in PET/MRI scanners are usually composed of lutetium ortho-oxysilicate, with the advantage of only minor disturbances of magnetic field homogeneity (Fig. 1). Next generation PET/MRI scanners could be based on silicon photomultiplier PET detectors, which showed better performance characteristics than the APDs and, in contrast to these, are capable of time-of-flight imaging (5). Secondly, the development of MR-based attenuation correction methods is necessary, as the commonly used method for attenuation correction in PET/CT systems, which is based on the absorption of X-rays, is not transferable to MRI. Hence, different methods for attenuation correction in PET/MRI systems have been proposed, one of which consists of segmentation of the attenuation map into four classes (background, lung tissue, fat, and soft tissue) (6). In principle, the MR-based attenuation map is created with a two-point Dixon sequence (7), providing water-only and fat-only images, which are combined and segmented to form an MR-based attenuation map. The method proved its technical feasibility with the limitation that in bone tissue and in its vicinity standardized uptake values (SUV) derived from PET/MRI systems might be erroneously underestimated when compared to SUVs derived from PET/CT (8). Therefore, SUVs derived from PET/MRI systems should be interpreted carefully until a larger experience with the new method of PET/MRI exists.Open in a separate windowFigure 1.Diagram of an integrated PET/MRI scanner with capability of simultaneous PET and MRI data acquisition. Image courtesy of Siemens Healthcare, Erlangen, Germany.In 2010, the first fully integrated whole-body PET/MR hybrid imaging system based on APD technology and MR-based attenuation correction became commercially available (Biograph mMR, Siemens Healthcare, Erlangen, Germany) (9). As of December 2013 more than 50 of these systems have been sold (>40 installed, 10 ordered) in Europe, North America, Asia, and Australia (10).     

Unidentified bright objects of spleen on arterial phase CT: mimicker of splenic vascular injury in blunt abdominal trauma

PURPOSEWe have described unidentified bright objects of spleen (UBOS), a hitherto undescribed entity, as hyperdense areas on arterial phase (AP) computed tomography (CT) seen in relation to splenic lacerations and are isodense to the normal parenchyma on portal venous phase with no correlate on digital subtraction angiography (DSA). UBOS mimic splenic vascular injuries like active contrast extravasation and pseudoaneurysm and need to be differentiated from them as it would have implications on patient management. We undertook this study to identify CT features of UBOS that can differentiate them from splenic vascular injuries and to calculate their diagnostic accuracy.METHODSThis retrospective study was approved by the institutional ethical committee and the need for informed consent was waived. Patients with splenic injury who had undergone dual-phase CT and DSA were included. All the lesions that were hyperdense on AP were evaluated for their outline, their relation to the adjacent/parallel margins of a laceration (margin sign), string of beads appearance, and the presence of adjacent normal parenchyma (adjacent parenchyma sign). The Hounsfield unit (HU) of the lesion and the aorta on the AP were also noted. The diagnostic accuracy of various signs for distinguishing UBOS from splenic vascular injuries was calculated using DSA as the reference standard.RESULTSOf 48 patients, 5 were excluded due to suboptimal quality of the examination or a time difference of more than 6 hours between the CT and DSA. A total of 54 hyperdense lesions were detected on AP in 43 patients. These were classified as vascular injuries (pseudoaneurysm, n=11; active contrast extravasation, n=11) and UBOS (n=32) based on DSA. The margin sign, string of beads appearance, and ill-defined outline had high specificity (95%, 86%, and 82%, respectively) but low sensitivity (50%, 65%, and 63%, respectively). The adjacent parenchyma sign had a moderate sensitivity and specificity of 84% and 77%, respectively. ROC analysis showed that a difference of 50 HU between the aorta and the lesion had a high sensitivity and specificity of 88.9% and 90.6%, respectively, with an area under the curve of 0.90.CONCLUSIONAn attenuation difference of over 50 HU between the aorta and the lesion and the presence of normal adjacent parenchyma had the highest diagnostic accuracy, while an ill-defined outline, string of beads appearance, and margin sign had high specificity but low sensitivity for differentiating UBOS from splenic vascular injuries.

Although there is a wide variation in the computed tomography (CT) protocol for the evaluation of blunt abdominal trauma across centers, arterial phase (AP) CT is increasingly being used as part of the evaluation (1–3). AP is usually acquired as a part of whole-body (chest and abdomen) CT angiography followed by a portal venous phase (PVP) acquisition of the abdomen (4–7). AP has been shown to increase the sensitivity of CT for the detection of splenic vascular injuries like pseudoaneurysms (6–9). These appear hyperdense relative to the surrounding parenchyma on AP, leading to better detection rates on AP. However, due to poorly understood mechanisms, the splenic parenchyma shows heterogeneous enhancement in the arterial phase (10–14). This is further exaggerated in the presence of parenchymal injuries like laceration following blunt abdominal trauma leading to the appearance of hyperdense areas on AP which may masquerade as intraparenchymal pseudoaneurysms or active extravasations.We describe unidentified bright objects of spleen (UBOS) as hyperdense areas seen in relation to splenic lacerations on AP CT which are isodense to the normal parenchyma on PVP with no abnormal correlate on digital subtraction angiography (DSA). As most splenic vascular injuries are hyperdense on AP and some of them isodense on PVP, these UBOS closely mimic splenic vascular injuries (Fig. 1).Open in a separate windowFigure 1. a, bIllustration depicting the imaging features of unidentified bright objects of spleen (UBOS) and pseudoaneurysm: UBOS (a, asterisk) show ill-defined outline, normal adjacent parenchyma, string of beads appearance due to multiple adjacent lesions, the presence of lesions on adjacent/parallel margins of laceration. Also, UBOS show no communication with the arterial and is less bright than the adjacent arteries (depicting lesser HU). Pseudoaneurysm (b, asterisk) shows a well-defined lesion with no adjacent normal parenchyma in direct communication with an artery. Brown shaded area represents a laceration with intraparenchymal hematoma.The 2018 revision of the organ injury scale for splenic injuries by the American Association for Surgery in Trauma (AAST) has incorporated CT-diagnosed vascular injuries into the grading system. The grade of injury is upgraded to grade 4/grade 5 if there are associated splenic vascular injuries irrespective of the grade of parenchymal injuries (15–17). Hence, it is imperative to accurately diagnose the splenic vascular injuries on CT and to differentiate UBOS, a previously undescribed entity, from splenic vascular injuries, as it would have implications on the grading of injury and further management.There are no studies describing such an entity or its imaging features. We undertook this retrospective study to describe CT features of UBOS and to identify features that can differentiate UBOS from pseudoaneurysms or active extravasations and test their diagnostic accuracy.     

Iliorenal periscope graft to maintain blood flow to accessory renal artery

Parallel endografts such as “chimney” and “periscope” are being increasingly used to maintain blood flow to visceral and supra-aortic branches in patients with different aortic disorders. We present a new technique, “iliorenal periscope graft”, in a patient with abdominal aortic aneurysm undergoing endovascular aortic repair. In this case, left accessory renal artery flows were provided by an iliorenal periscope graft that extends from the left accessory renal artery to the right common iliac artery in a retrograde fashion.Fenestrated and branched endografts have been developed to extend proximal and/or distal landing zone in aortic diseases with short proximal and/or distal necks; however, the applicability of these devices are currently very limited (1, 2). Parallel endografts have been recently used for the same purpose (3). These grafts can also be used to maintain flow to the accessory renal arteries. We have successfully applied a new technique similar to periscope graft (PG), in which the PG is extended from the accessory renal artery (ARA) to the common iliac artery (CIA) and blood flow of the ARA is maintained by the iliorenal periscope graft (IRPG) in a retrograde fashion.     

Proximal iliac limb extension and embolization: a new technique of complete endovascular management of an unfavorably sited type III endoleak

Type III endoleak is an uncommon but life-threatening complication of endovascular aortic repair, and such leaks at certain sites can be challenging to treat through an endovascular route. A 77-year-old man presented with severe abdominal pain and was found to have an abdominal aortic aneurysm with contained rupture due to an unfavorably cited type IIIb endoleak. He was successfully treated with an endovascular approach using bilateral iliac limb proximal extension combined with embolization of endoleak sac, endoleak site and the feeding recess, preserving flow through both the iliac limbs obviating the need for an additional femorofemoral bypass. The patient improved clinically and had a favorable long-term follow-up profile.

Endoleak is the most common complication of endovascular aortic repair requiring re-intervention (1). There are five types of endoleak; type III is a less common but the most dangerous variety (2, 3). Endovascular repair is preferred over surgical repair and different treatment options exist depending on the site of endoleak (4). Because of its location, a type IIIb endoleak from a defect in the graft at or close to the endograft bifurcation cannot be treated by simple relining with an aortic extender cuff or an iliac limb, and is usually endovascularly treated by insertion of an aorto-uni-iliac stent graft along with occlusion of contralateral limb and a surgical femorofemoral bypass; the other option being insertion of a bifurcated stent graft if there is sufficient length between renal artery origin and endograft bifurcation (1, 4, 5). We describe the first case of a successfully treated unfavorable type IIIb endoleak using proximal extension of iliac limbs, endoleak sac and feeding recess embolization.     

Fatty lesions in and around the heart: a pictorial review

A wide variety of fat-containing entities occur in and near the heart. These findings are often encountered by radiologists and may be incidental or the reason for the patient''s clinical presentation. Cross-sectional imaging helps to characterize the extent of these lesions and to formulate a differential diagnosis, which varies by lesion location, imaging features and patient demographics. The purpose of this pictorial essay is to familiarize radiologists with these fat-containing lesions and to help avoid misdiagnosis and errors in management. This pictorial review will discuss the normal fatty structures in and around the heart. A range of common and uncommon fat-containing lesions will then be reviewed based upon lesion location.There is a wide range of fat-containing lesions that can occur in and around the heart (Figure 1).^1–5 Clinical findings of such lesions are frequently non-specific with many found incidentally on imaging studies performed for other reasons. Some may be detected on chest radiography or echocardiography; however, CT and MR are the preferred modalities for more definitive characterization. Awareness of the different causes and appearances of these lesions will aid in formulating a differential diagnosis, help to guide additional evaluation and potentially avoid unnecessary work-up for some lesions.Open in a separate windowFigure 1.Flow chart providing an overview fat-containing lesions encountered in and near the heart, organized by location. ARVD, arrhythmogenic right ventricular dysplasia; LHIAS, lipomatous hypertrophy of the interatrial septum; MI, myocardial infract; RVOT, right ventricular outflow tract; TSC, tuberous sclerosis complex.     

Chest X-ray in intensive care unit patients: what there is to know about thoracic devices

Critically ill patients admitted to the intensive care unit require continuous monitoring of vital functions as well as mechanical and pharmacological support, provided through different devices. Chest radiographs play a fundamental role in monitoring the conditions of these patients and assessing the intensive-care devices after their insertion; therefore, the radiologist needs to know their normal appearance and their correct position and should be aware of the possible complications that may occur after their placement. This pictorial review illustrates the radiographic appearance of non-cardiological devices commonly used in clinical practice (central venous catheters, tunneled catheters, Swan-Ganz catheters, chest tubes, endotracheal tubes, and nasogastric tubes), their correct position and the most common complications that may occur after their placement.

Critically ill patients in the intensive care unit require continuous monitoring of vital functions and mechanical and pharmacological support, provided through different devices. Inserting intensive-care devices is a common medical practice but complications may occur and a chest X-ray radiography (CXR) should be performed immediately after placement (1). The widespread availability along with low radiation exposure and low costs, give CXR a decisive role in these settings to assess the position of the device, the response to therapy and the occurrence of any complications (2) (Fig. 1). Radiologists should be aware of the normal appearance of these devices and promptly recognize any abnormal findings.Open in a separate windowFigure 1A technically correct bedside chest X-ray performed in the intensive care unit. The exam allows to evaluate the position of inserted chest devices (chest tubes, black asterisks; endotracheal tube, white asterisk; pulmonary artery catheter, black arrowhead; nasogastric tube – proximal portion, white arrowhead) and to detect the presence of bilateral pleural effusions (white arrows) and the occurrence of soft tissue emphysema (black arrow). The patient underwent heart surgery and prosthetic valves, median sternotomy wires and external cardiac monitor wires are also present.This pictorial review illustrates the radiographic appearance of commonly used non-cardiological devices (

Combined Y-configured stents for revising occluded transjugular intrahepatic portosystemic shunt

PURPOSEWe aimed to determine the technical feasibility, safety and prognosis of the transjugular intrahepatic portosystemic shunt (TIPS) revision by combined Y-configured stents placement.METHODSWe retrospectively evaluated 12 patients who received TIPS revision using Y-stenting technique between June 2015 and January 2019. The rates of technical success, complication, shunt patency, hepatic encephalopathy and mortality were described and analyzed.RESULTSThe combined Y-configured stents were successfully placed in 11 of 12 patients (92%) without major complications. The median portosystemic pressure gradient (PPG) decreased from 23 mmHg (interquartile range, IQR, 18.5–27.5 mmHg) to 10 mmHg (IQR, 9–14 mmHg). The left internal jugular vein approach was used in 5 patients. Four patients required a shunt extension with an extra stent to resolve the stenosis at the portal venous terminus. Two patients developed hepatic encephalopathy, which was medically controlled within 3 months after the procedure. The TIPS patency and survival rates were both 100% during a median follow-up period of 10 months (IQR, 5.5–14 months).CONCLUSIONTIPS revision by combined Y-configured stents placement was technically feasible and safe with favorable clinical outcomes.

Transjugular intrahepatic portosystemic shunt (TIPS) has been widely used for the treatment of portal hypertension complications by decompressing the portal venous system (1). Shunt patency has been greatly improved since the introduction of dedicated polytetrafluoroethylene-covered stents. However, dysfunction still occurs in 8%–20% of patients within the first year after TIPS creation (2).TIPS dysfunction can arise from acute thrombosis and pseudointimal hyperplasia within the stent or at the hepatic vein outflow (3–5). Angioplasty, with or without stent placement, is frequently attempted to restore adequate TIPS function. In some cases where TIPS dysfunction is associated with altered shunt configuration or stent displacement, especially in a “T-bone” configuration, entry to the previous shunt seems to be challenging (6). This troublesome situation is more likely to occur when TIPS is created with a non-Viatorr stent, such as Fluency stent-grafts (Bard & BD). This type of stent is still widely used due to its relatively low cost, though its rigid structure may change the shunt orientation gradually. Moreover, a combined transjugular and transhepatic approach has been described (7, 8). After a percutaneous transhepatic puncture of the stent strut, a wire is passed through the lumen to inferior vena cava (IVC) and snared from the transjugular access to establish the channel. Of note, this approach brings a relatively high risk for bleeding and prolonged operative time when compared with only transjugular access (9). Parallel TIPS is generally used as the last resort (10, 11). Despite its proven efficacy, parallel stent placement through the portal vein may increase the risk of intraabdominal hemorrhage and aggravate liver function.Herein, inspired by the stent-in-stent technique used in the placement of bilateral biliary metallic stents and coronary stents (12–14), we tried to recanalize the occluded TIPS via endovascular puncture of the strut of the existent stent and followed with deployment of a new covered stent with a “Y” configuration (Fig. 1). The purpose of the present study is to evaluate the technical feasibility, safety and clinical outcomes of this new TIPS revision technique.Open in a separate windowFigure 1A schematic of Y-configured stents implantation. The angle between the initial stent (arrowheads) and the right hepatic vein was approximately 90°. A new stent (long arrow) was deployed through the mesh of the initial stent to restore the portosystemic shunt.     

Temporary Stent-Assisted Coil Embolization as a Treatment Option for Wide-Neck Aneurysms

BACKGROUND AND PURPOSE:Simple coil embolization is often not a feasible treatment option in wide-neck aneurysms. Stent-assisted coil embolization helps stabilize the coils within the aneurysm. Permanent placement of a stent in an intracranial vessel, however, requires long-term platelet inhibition. Temporary stent-assisted coiling is an alternative technique for the treatment of wide-neck aneurysms. To date, only case reports and small case series have been published. Our purpose was to retrospectively analyze the effectiveness and safety of temporary stent-assisted coiling in a larger cohort.MATERIALS AND METHODS:Research was performed for all patients who had undergone endovascular aneurysm treatment in our institution (University Hospital Aachen) between January 2010 and December 2015. During this period, 355 consecutive patients had undergone endovascular aneurysm treatment. We intended to treat 33 (9.2%) of them with temporary stent-assisted coiling, and they were included in this study. Incidental and acutely ruptured aneurysms were included.RESULTS:Sufficient occlusion was achieved in 97.1% of the cases. In 94%, the stent could be fully recovered. Complications occurred in 5 patients (14.7%), whereas in only 1 case was the complication seen as specific to stent-assisted coiling.CONCLUSIONS:Temporary stent-assisted coiling is an effective technique for the treatment of wide-neck aneurysms. Safety is comparable with that of stent-assisted coiling and coiling with balloon remodeling.

Simple coil embolization is often not a feasible treatment option in wide-neck aneurysms. Stent-assisted coil embolization helps stabilize the coils within the aneurysm.¹ Permanent placement of a stent in an intracranial vessel, however, requires long-term platelet inhibition. Platelet inhibition is known to be associated with a higher bleeding risk.² Particularly in patients who require further treatment in an intensive care unit, such as patients with an acute subarachnoid hemorrhage, a higher bleeding risk should be avoided. In addition, dual platelet inhibition as recommended when stents are deployed permanently, increases the risk for cerebral hemorrhage within potentially existent ischemic brain tissue due to vasospasms.³ Hence, avoiding permanent stent placement is an advantage in patients with acute SAH.In the past, several techniques have been established for the treatment of wide-neck aneurysms. Common techniques are stent-assisted coiling, balloon-assisted coiling, double microcatheter coiling, and aneurysm treatment with dedicated devices such as the Woven EndoBridge (WEB; Sequent Medical, Aliso Viejo, California) device^4,5 or the Comaneci device (Rapid Medical, Yokneam, Israel).^6,7 The combination of balloon remodeling and stent-assisted coiling is another treatment option with possible achievement of higher occlusion rates.⁸Stent-assisted coiling and balloon remodeling seem to have a comparable complication rate in the literature, ranging between 10% and 20%.^9,10Treatment of wide neck-aneurysms is also possible with flow diverter devices with an occlusion rate of about 80%.¹¹ However, with a latency of 4–12 months to aneurysm thrombosis and the need for subsequent platelet inhibition, these are not a primary option in patients with an acutely ruptured intracranial aneurysm.Another treatment option for wide-neck aneurysms is temporary stent-assisted coiling.^12,13 For this purpose, 2 microcatheters are used. The first microcatheter is used to cover the aneurysm neck and deploy the stent. The second microcatheter is advanced into the aneurysm to perform coil embolization. Advancement of the second microcatheter into the aneurysm can be performed either before deployment of the stent or after stent deployment.¹⁴ The stent is deployed to cover the aneurysm neck but is not fully released. After coil embolization has been completed, the stent is recovered (Figs 1 and ​and2).2). In the unlikely event of coil protrusion during the process of recovery of the stent, recovery is stopped, the stent is deployed again, and it is released for permanent implantation. Temporary stent-assisted coiling is an established standard technique in our institution for the treatment of wide-neck aneurysms. Because to date, only case reports and small case series have been published, we analyzed a larger cohort of patients treated with temporary stent-assisted coiling.^12,13 Following, we present a retrospective analysis on the effectiveness and safety of temporary stent-assisted coiling.Open in a separate windowFig 1.A, An aneurysm of the anterior communicating artery before coiling. B, The same aneurysm partially coiled with a deployed Solitaire stent from the left A1 to the right A2 segment. C, The same aneurysm after complete coil embolization. The Solitaire stent has been recovered.Open in a separate windowFig 2.A, A carotid-T aneurysm before coiling. B, The same aneurysm partially coiled with the deployed Solitaire stent from the internal carotid artery to the left M1 segment. C, The same aneurysm after complete coil embolization. The Solitaire stent has been recovered.     

The value of angio-CT system on splanchnic nerve neurolysis

PURPOSEWe aimed to evaluate the effectiveness and safety of splanchnic nerve neurolysis (SNN) with angio-CT, a hybrid system combining computed tomography (CT) with X-ray fluoroscopy.METHODSThirty-three SNN procedures with angio-CT performed in 30 patients with severe epigastric cancer pain (11 males and 19 females; median age, 57 years; age range, 19–79 years) between January 2010 and July 2017 were retrospectively evaluated. The primary endpoints were the technical success and adverse event rates. The secondary endpoints included the clinical success rate, defined as a reduction in the numerical rating scale for pain score or a decrease in the consumption of analgesics on day 1 and at 1–2 weeks after the procedure; procedure time; the number of needle punctures; amount of ethanol required; and the distribution of contrast medium in the retrocrural space. These endpoints were compared with previous studies that did not employ the angio-CT system.RESULTSThe technical success rate was 96.97%. There were two procedure-related adverse events (one retroperitoneal hemorrhage, one pneumothorax). The clinical success rates on day 1 and at 1–2 weeks after the procedure were 84.38% and 87.5%, respectively. The median procedure time was 60 minutes. The median number of needles used was 2. The median amount of ethanol used was 20 mL.CONCLUSIONSNN under angio-CT is safe and effective, with excellent technical and clinical success rates and acceptable adverse event rates. These results are comparable with previous studies that did not involve angio-CT. However, the use of angio-CT allows for easier needle positioning and an earlier response to complications compared with conventional methods.

Splanchnic nerve neurolysis (SNN) has been established as an effective palliative treatment for intractable cancer pain in the upper abdomen (1–6). The splanchnic nerve is located in the retrocrural space, which is a narrow area surrounded by the crura of the diaphragm, vertebral bodies, and aorta (Fig. 1). This makes it difficult to access this space and achieve adequate local distribution of drugs. X-ray fluoroscopy, computed tomography (CT), and endoscopic ultrasonography (EUS) are the imaging modalities generally used for SNN; however, each of these alone cannot provide real-time, high spatial resolution images of the coronal, axial, and sagittal planes, or three-dimensional visualization. With angio-CT, X-ray fluoroscopy, conventional CT, and CT fluoroscopy images can be obtained on the same sliding table when needed. Therefore, the purpose of this retrospective study was to evaluate the usefulness of angio-CT in SNN.Open in a separate windowFigure 1Axial CT image shows normal splanchnic and celiac ganglions. The splanchnic nerve is located in the retrocrural space, which is a narrow area surrounded by the crura of the diaphragm, vertebral bodies, and aorta (arrows). However, the celiac plexus is located over the anterolateral surface of the aorta and around the origin of the celiac trunk (arrowheads).     

Splenic peliosis: an unusual entity

This case of splenic peliosis, describes a rare condition when it presents in the spleen, and is better understood when it occurs in the liver. However, the ultrasound and CT features have a wide differential diagnosis including more common aetiologies, of either a vascular, infective or neoplastic nature, which should be considered. Peliosis is an important condition to be aware of because rupture of the blood-filled cysts on the spleen surface can lead to haemorrhagic peritonitis and ultimately be fatal.A 56-year-old female shop assistant presented acutely with abdominal pain, anorexia and weight loss. Her past medical history included pneumonia, hypothyroidism and irritable bowel syndrome. She was not taking any prescribed medication.An ultrasound of the abdomen was performed, which showed a spleen that was normally sized but that had heterogeneous echotexture, and multiple fluid-filled and echogenic areas. There was also an echo-poor area of 2 cm in the lower pole of the spleen (Figure 1). The other solid organs had normal sonographic appearances.Open in a separate windowFigure 1Ultrasound image demonstrating a normal size spleen, with hypoechoic areas in the lower pole, the larger of which measures 2 cm. The white arrow indicates a hypoechoic area within the spleen.The patient underwent a contrast-enhanced CT scan of the abdomen and pelvis, which showed multiple round focal areas of decreased enhancement within the spleen (Figures 2 and ​and3).3). Initially, these were thought to be due to infiltration of lymphoma. There was no other evidence of nodal disease but the patient was found to have a sigmoid carcinoma and underwent curative surgery including splenectomy. She made a full post-operative recovery and started adjuvant chemotherapy. Several follow-up CT scans have not shown any recurrence.Open in a separate windowFigure 2Portal venous phase axial CT images showing areas of decreased attenuation within the spleen.Open in a separate windowFigure 3Portal venous phase axial CT images showing areas of decreased attenuation within the spleen.Histopathology demonstrated a normal-sized spleen, involving numerous cystic lesions lined by fibrous tissue, and containing cholesterol crystals and fibrinoid debris with adjacent giant-cell reaction to foreign bodies. No epithelial or endothelial lining was identified. There were also dilated blood-filled vascular spaces (Figure 4). There was no evidence of lymphoma or metastatic disease. Stains for fungal infection were negative. The disease appearances were consistent with peliosis of the spleen. The sigmoid specimen confirmed a moderately differentiated adenocarcinoma with one out of 21 nodes was positive.Open in a separate windowFigure 4Histopathology slide from the splenectomy specimen illustrating the vascular pools within the splenic white substance.     

Follow-up of true visceral artery aneurysm after coil embolization by three-dimensional contrast-enhanced MR angiography

PURPOSE

We aimed to evaluate the outcomes of coil embolization of true visceral artery aneurysms by three-dimensional contrast-enhanced magnetic resonance (MR) angiography.

MATERIALS AND METHODS

We used three-dimensional contrast-enhanced MR angiography, which included source images, to evaluate 23 patients (mean age, 60 years; range, 28–83 years) with true visceral artery aneurysms (splenic, n=15; hepatic, n=2; gastroduodenal, n=2; celiac, n=2; pancreaticoduodenal, n=1; gastroepiploic, n=1) who underwent coil embolization. Angiographic aneurysmal occlusion was revealed in all cases. Follow-up MR angiography was conducted with either a 1.5 or 3 Tesla system 3–25 months (mean, 18 months) after embolization. MR angiography was evaluated for aneurysmal occlusion, hemodynamic status, and complications.

RESULTS

Complete aneurysmal occlusion was determined in 22 patients (96%) on follow-up MR angiography (mean follow-up period, 18 months). Neck recanalization, which was observed at nine and 20 months after embolization, was confirmed in one of eight patients (13%) using a neck preservation technique. In this patient, a small neck recanalization covered by a coil mass was demonstrated. The complete hemodynamic status after embolization was determined in 21 patients (91%); the visualization of several collateral vessels, such as short gastric arteries, after parent artery occlusion was poor compared with that seen on digital subtraction angiography in the remaining two patients (9%). An asymptomatic localized splenic infarction was confirmed in one patient (4%).

CONCLUSION

Our study presents the follow-up results from three-dimensional contrast-enhanced MR angiography, which confirmed neck recanalization, the approximate hemodynamic status, and complications. This effective and less invasive method may be suitable for serial follow-up after coil embolization of true visceral aneurysms.True visceral artery aneurysms are a rare and uncommon form of vascular disease often found incidentally in 0.09% to 2% of the general population (1–3). However, these true aneurysms have an incidence of rupture and mortality rate of 20% to 75% due to life-threatening hemorrhage (4, 5). Aneurysms can be saccular or fusiform. Endovascular treatment of true visceral artery aneurysms using coil embolization has been reported as an invasive and effective procedure to prevent rupture (6).Various modalities have been used as follow-up evaluation methods after coil embolization of visceral artery aneurysms, including computed tomography (CT), magnetic resonance (MR) angiography, ultrasonography (US), and digital subtraction angiography (DSA) (6, 7). However, specific methods and the ideal follow-up times after coil embolization of visceral artery aneurysms are not well established. Coil embolization of visceral artery aneurysms occasionally result in neck recanalization, growth of a residual aneurysm neck or body remnant, organ infarction, and coil migration (7–9). In particular, one group reported that neck recanalization was effectively followed up by three-dimensional (3D) contrast-enhanced MR angiography (CEMR angiography) (8).The aim of the present study was to evaluate the outcomes of coil embolization of true visceral artery aneurysms and to assess the role of 3D CEMR angiography as a follow-up method.