Application of 3D Printing in Preoperative Planning.

Preoperative planning is critical for success in the surgical suite. Current techniques for surgical planning are limited; clinicians often rely on prior experience and medical imaging to guide the decision-making process. Furthermore, two-dimensional (2D) presentations of anatomical structures may not accurately portray their three-dimensional (3D) complexity, often leaving physicians ill-equipped for the procedure. Although 3D postprocessed images are an improvement on traditional 2D image sets, they are often inadequate for surgical simulation. Medical 3D printing is a rapidly expanding field and could provide an innovative solution to current constraints of preoperative planning. As 3D printing becomes more prevalent in medical settings, it is important that clinicians develop an understanding of the technologies, as well as its uses. Here, we review the fundamentals of 3D printing and key aspects of its workflow. The many applications of 3D printing for preoperative planning are discussed, along with their challenges.

Bland Embolization of Benign Liver Tumors: Review of the Literature and a Single Center Experience.

Transarterial embolization has shown promise as a safe, effective, and less invasive treatment modality for benign liver lesions (hemangioma, focal nodular hyperplasia (FNH), and hepatic adenoma (HA)) with fewer complications compared to surgical intervention. There is no consensus regarding the most appropriate embolization material(s) for the treatment of benign liver tumors. The purpose of this study was to review the current literature regarding the transarterial embolization of benign liver tumors and to share our single center experience. This was a non-blinded, retrospective, single-institution review of the bland embolization of benign liver tumors. Clinical data and imaging before and after embolization were used to evaluate lesion response to transarterial embolization. Twelve patients were included in the study. Five patients with six hemangiomas were treated. Pain was a presenting complaint in all five of these patients. The median change in tumor volume was -12.4% and ranged from -30.1% to +42.3%. One patient with two FNH lesions was treated, and both lesion volumes decreased by more than 50%. Six patients with 10 adenomas were treated. Pain was a presenting complaint in three patients, and five patients had a lesion >5 cm. The median change in tumor volume was -67.0% and ranged from -92.9% to +65.8%. Bland transarterial embolization of liver hemangiomas, FNH, and HA can be an effective and minimally invasive treatment modality to control the size and/or symptoms of these lesions. There is a variable response depending on tumor type and the embolization materials used.

Percutaneous Embolization of an Inferior Mesenteric Artery Aneurysm in a Patient With Type IV Ehlers-Danlos Syndrome.

Ehlers-Danlos syndrome (EDS) refers to a group of genetic disorders involving the connective tissues. Type IV EDS impairs type III collagen that is responsible for vessel integrity. Patients with type IV EDS are susceptible to vascular and visceral complications, including aortic aneurysms, pseudoaneurysms, dissections, and spontaneous rupture of internal organs. Treating aneurysms with open surgery versus endovascular techniques each carry a unique risk-to-benefit ratio that must be applied to each individual carefully. We present a patient with type IV EDS who presented with a rapidly growing inferior mesenteric artery aneurysm. The patient was treated with a percutaneous endovascular technique using coils and n-butyl-cyanoacrylate glue.

Endovascular Retrieval of an Embolized Atrial Septal Occluder Device From the Abdominal Aorta.

Patent foramen ovale (PFO) is a common heart condition in adults. Closure with a septal occluder device is a safe, well-established treatment option with excellent clinical outcomes. One rare complication of percutaneous PFO closure is embolization of the device to the heart chambers or distal vasculature. Most device migrations are recognized during or shortly after implantation. While many endovascular retrievals of migrated devices are successful, there are still a high percentage of surgical interventions performed. We report a case of a septal occluder device that embolized to the abdominal aorta and was discovered 7 days after implantation. Endovascular techniques with a snare and endobronchial forceps were used to retrieve the device safely.

Developing Interventional Radiology Anticoagulation Guidelines: Process and Benefits †.

We created, posted, and updated radiology department anticoagulation guidelines and identified various steps in the process, including triggering events, consensus building, legal analysis, education, and distribution of the guidelines to nurses and clinicians. Supporting data collected retrospectively, before and after implementation, included nursing satisfaction survey results and the number of procedure cancellations. After the guidelines were developed and posted, significantly fewer procedures were cancelled, nursing satisfaction was higher, and radiologists performed procedures with less variability. Anecdotally, radiologists had fewer queries about anticoagulation. The development and dissemination of radiologic procedure anticoagulation guidelines should be considered as a departmental quality improvement project.

Segmental Arterial Mediolysis: Abdominal Imaging of and Disease Course in 111 Patients.

OBJECTIVE: The purpose of this study is to identify the imaging characteristics of segmental arterial mediolysis (SAM) at presentation and establish the longitudinal course of disease. MATERIALS AND METHODS: We retrospectively identified patients with SAM at a single institution from 2000 through 2015. Diagnosis was based on published guidelines with multidisciplinary consensus. Imaging studies obtained at initial evaluation were reviewed to evaluate imaging findings and vascular territory distribution. All subsequent follow-up imaging studies were reviewed to assess for progression, stability, or regression. RESULTS: We identified 111 patients (79 men and 32 women; median age, 51 years) who met the diagnostic criteria for SAM. Abdominal pain was the most common presentation (74%), followed by flank pain (21%). SAM most commonly affected the renal arteries (47%), superior mesenteric artery (46%), celiac trunk (46%), hepatic artery (23%), iliac arteries (18%), and splenic artery (14%). The most common imaging findings were dissection (86%), aneurysm (57%), beading or webs (28%), occlusion (19%), and a rind or wall thickening (15%). The 247 available follow-up imaging studies for 97 patients (median follow-up, 12 months) showed progression in 19 patients (20%), with either stability or regression observed in the remaining patients. CONCLUSION: SAM most commonly affects the renal arteries, superior mesenteric artery, and celiac artery. Dissections and aneurysms are the most common imaging findings. Follow-up imaging studies show stability or regression in most patients.

Rationale for catheter directed therapy in pulmonary embolism.

Pulmonary embolism (PE) is a widespread health concern associated with major morbidity and mortality. Catheter directed therapy (CDT) has emerged as a treatment option for acute PE adding to the current potential options of systemic thrombolysis or anticoagulation. The purpose of this review is to understand the rationale and indications for CDT in patients with PE. While numerous studies have shown the benefits of systemic thrombolysis compared to standard anticoagulation, these are balanced by the increased risk of major bleeding. With this in mind, CDT has the potential to offer the benefits of systemic thrombolysis and in theory, a reduced risk of bleeding. This article will review current treatment guidelines in both massive and submassive PE evaluating both short and long term benefits. The role of CDT will be highlighted, with an emphasis on efficacy and safety.

Feasibility of ultra-low radiation dose reduction for renal stone CT using model-based iterative reconstruction: prospective pilot study.

PURPOSE: To compare dose, reader assessments, and noise between ultra-low-dose (ULD) and low-dose (LD) renal stone computed tomography (CT) using multiple reconstruction methods. MATERIALS AND METHODS: Prospective study of 19 patients having noncontrast LD and ULD renal stone CT reconstructed using filtered back projection, adaptive statistical iterative reconstruction (ASIR), and model-based iterative reconstruction (MBIR). Dose, noise measurements, and subjective image assessments were recorded. RESULTS: ULD volume CT dose index was 61% less. Noise was 50% less with ULD MBIR than with LD ASIR (P<.001); no other significant differences existed. CONCLUSION: ULD MBIR is comparable to our standard of care, LD ASIR, with 61% lower dose and 50% less noise.

The accordion sign in the transplant ureter: ramifications during balloon dilation of strictures.

PURPOSE: This study was designed to demonstrate the accordion sign within the transplant ureter and evaluate its ramifications during balloon dilation of strictures. METHODS: A retrospective electronic chart and imaging review included demographic characteristics, procedure reports, and complications of 28 renal transplant patients having ureteral strictures treated with percutaneous balloon dilation reported in our transplant nephrology database during an 8-year period. The accordion sign was deemed present or absent on the basis of an imaging review and was defined as present when a tortuous ureter became kinked and irregular when foreshortened after placement of a wire or a catheter. Procedure-related urine leaks were categorized as occurring at the stricture if within 2 cm; otherwise, they were considered away from the stricture. RESULTS: The accordion sign was associated with a significantly greater occurrence of leaks away from the stricture (P = 0.001) but not at the stricture (P = 0.34). CONCLUSIONS: The accordion sign is an important consideration when performing balloon dilation procedures on transplant ureteral strictures, given the increased risk of leak away from the stricture. Its presence should prompt additional care during wire and catheter manipulations.

Ultra-low-dose computed tomographic angiography with model-based iterative reconstruction compared with standard-dose imaging after endovascular aneurysm repair: a prospective pilot study.

PURPOSE: An ultra-low-dose radiation protocol reconstructed with model-based iterative reconstruction was compared with our standard-dose protocol. METHODS: This prospective study evaluated 20 men undergoing surveillance-enhanced computed tomography after endovascular aneurysm repair. All patients underwent standard-dose and ultra-low-dose venous phase imaging; images were compared after reconstruction with filtered back projection, adaptive statistical iterative reconstruction, and model-based iterative reconstruction. Objective measures of aortic contrast attenuation and image noise were averaged. Images were subjectively assessed (1 = worst, 5 = best) for diagnostic confidence, image noise, and vessel sharpness. Aneurysm sac diameter and endoleak detection were compared. RESULTS: Quantitative image noise was 26% less with ultra-low-dose model-based iterative reconstruction than with standard-dose adaptive statistical iterative reconstruction and 58% less than with ultra-low-dose adaptive statistical iterative reconstruction. Average subjective noise scores were not different between ultra-low-dose model-based iterative reconstruction and standard-dose adaptive statistical iterative reconstruction (3.8 vs. 4.0, P = .25). Subjective scores for diagnostic confidence were better with standard-dose adaptive statistical iterative reconstruction than with ultra-low-dose model-based iterative reconstruction (4.4 vs. 4.0, P = .002). Vessel sharpness was decreased with ultra-low-dose model-based iterative reconstruction compared with standard-dose adaptive statistical iterative reconstruction (3.3 vs. 4.1, P < .0001). Ultra-low-dose model-based iterative reconstruction and standard-dose adaptive statistical iterative reconstruction aneurysm sac diameters were not significantly different (4.9 vs. 4.9 cm); concordance for the presence of endoleak was 100% (P < .001). CONCLUSION: Compared with a standard-dose technique, an ultra-low-dose model-based iterative reconstruction protocol provides comparable image quality and diagnostic assessment at a 73% lower radiation dose.

Primary percutaneous treatment of transplant ureteral strictures using tandem stents.

PURPOSE: To evaluate outcomes of primary (first-occurrence) treatment of renal transplant ureteral strictures using tandem parallel internal double-pigtail stents. MATERIALS AND METHODS: A retrospective electronic chart review, including demographics, medical history, stricture intervention, and outcomes, was performed of patients with renal transplants with first-occurrence ureteral obstructions or leaks reported in a transplant nephrology database over a 4-year period, with a focus on patients treated primarily with tandem stents. RESULTS: Of 27 patients with first-occurrence ureteral obstruction or ureteral leak, 18 (67%) were treated primarily using tandem internal stents, with 15 (83%) of 18 stent-free for a minimum 90 days of follow-up. There was no significant difference between outcomes for male versus female patients (P>.99) or early versus late strictures (P = .53). Urinary tract infections (UTIs) occurred in 14 (78%) of 18 patients with tandem stents in place. Four patients were hospitalized<48 hours with UTI and sepsis; there were no other major complications. CONCLUSIONS: Patients with renal transplants can be successfully managed nonsurgically using tandem ureteral stents for the primary treatment of first-occurrence ureteral stricture. These patients may require more intensive monitoring for UTIs.

Endovascular retrieval of a TrapEase permanent inferior vena cava filter from the aorta.

Intra-aortic inferior vena cava filter placement is a rare event. We describe a case in which a permanent vena caval filter was retrieved from the aorta with endovascular techniques. Knowledge of filter design, catheters, and available wires is important to perform this procedure safely.

Incidence of highly important extravascular findings detected on CT angiography of the abdominal aorta and the lower extremities.

OBJECTIVE: The purpose of this study was to determine the frequency and significance of extravascular findings on CT angiography of the abdominal aorta and lower extremities. MATERIALS AND METHODS: Reports of CT angiograms of the abdominal aorta and lower extremities for 275 patients (164 men and 111 women; mean age, 72 years) were retrospectively reviewed. Patients were scanned from the level of diaphragm to toes. Extravascular findings were classified into three groups-low, moderate, and high importance-on the basis of clinical significance. Low-importance findings were defined as those with little, if any, clinical significance. Moderate-importance findings were those that may not be clinically apparent but recognition of which could be beneficial at a later time. Highly important findings were defined as previously unknown results requiring further imaging or investigation. For highly important findings, electronic chart review determined the subsequent clinical course. RESULTS: Highly important extravascular findings were found in 40 (15%) patients. Of 462 findings overall, 43 (9%) were of high importance, 77 (17%) were of moderate importance, and 342 (74%) were of low importance. The most common highly important findings were indeterminate lesions of kidney (n = 9), lung (n = 7), and liver (n = 6). Overall, eight (3%) of the 275 patients had findings of high clinical significance that resulted in medical therapy or surgical intervention, including lung carcinoma, renal cell carcinoma, colon carcinoma, cholangiocarcinoma, and pulmonary coccidioidomycosis. CONCLUSION: Of patients undergoing CT angiography of the abdominal aorta and lower extremities, 15% had previously undiagnosed, highly important findings. Radiologists and referring clinicians should be aware of the frequency of these clinically significant extravascular findings at CT angiography.

Vaginal paraganglioma presenting as a pelvic mass.

Paragangliomas are extra-adrenal neuroendocrine neoplasms derived from neural crest precursors. These tumors rarely arise from the female genital tract. Vaginal paragangliomas are extremely rare. We describe a case of vaginal paraganglioma managed with minimally invasive surgical techniques.

Direct percutaneous embolization of bleeding stomal varices.

Stomal variceal bleeding can develop in patients with underlying cirrhosis and portal hypertension. Most patients are best treated with transjugular intrahepatic portosystemic shunt (TIPS) creation because this addresses the underlying problem of portal hypertension. However, some patients are not good candidates for TIPS creation because they have end-stage liver disease or encephalopathy. We describe such a patient who presented with recurrent bleeding stomal varices, which was successfully treated with percutaneous coil embolization. The patient had bleeding-free survival for 1 month before death from unrelated causes.

Percutaneous embolization of a lumbar pseudoaneurysm in a patient with type IV Ehlers-Danlos syndrome.

Ehlers-Danlos syndrome (EDS) is a rare hereditary connective tissue disorder. Patients with type IV EDS are prone to develop visceral pseudoaneurysms and aortic aneurysms. Surgical and endovascular interventions are fraught with complications and high morbidity. We present a case of a patient with type IV EDS who presented with a new psoas pseudoaneurysm arising from a hypertrophied lumbar artery which was treated with percutaneous embolization by using n-butyl cyanoacrylate glue and coils.

Endovascular lung perfusion using high-dose cisplatin: uptake and DNA adduct formation in an animal model.

Mean survival after diagnosis of unresectable pulmonary metastases is less than one year. Isolated lung perfusion (ILP) is a technique that delivers chemotherapy into the pulmonary artery via a thoracotomy. Human trials are limited. We report an animal model for endovascular lung perfusion (ELP). Twelve swine were used. Treatment swine (N=6) received 150-mg of cisplatin (CDDP) into the pulmonary artery via a balloon occlusion catheter while nine grams of thiosulfate was given IV. Control swine (N=6) received 50-mg CDDP IV with sham pulmonary artery perfusion. Animals were sacrificed immediately (0 h), 4 or 24 h after infusion. Pulmonary and renal platinum/DNA adducts and serum CDDP levels were measured at all time points. Area under the adduct-time curve (AUA) was determined as a measure of systemic exposure. Pathologic study of the lungs was performed. At 0 h, ELP elevated pulmonary adduct levels by 17.38 times while thiosulfate led to reduction in renal DNA adducts despite the elevated CDDP dose. At all time points, pulmonary adducts were at least 6.9 times higher for ELP compared to IV administration. The AUA was 7 times greater for the ELP group. Serum CDDP levels were significantly higher after ELP (p<0.05). There was no evidence of toxic pulmonary injury from ELP. Direct pulmonary artery infusion of CDDP results in greater DNA adduct formation than would be expected from simple dose escalation. Further study of ELP evaluating the acute and chronic effects of repeated treatment administration is warranted.