The 3-Dimensional Temporal Bone Dissection Manual: Operable Stepwise Models for Teaching Otologic Surgery.

Deconstructing surgeries into steps and providing instructions with illustrations has been the staple of surgical textbooks for decades. However, it may be difficult for the novice surgeon to interpret 2-dimensional (2D) illustrations into 3D surgeries. The objective of this study is to create operable models that demonstrate the progression of surgery in 3D and allow for mastering the final steps of the operation first. Mastoidectomy was performed in a stepwise fashion to different end points on 5 identical 3D-printed temporal bone models to represent 5 major steps of the operation. The drilled models were computed tomography scanned and the subsequent images were used to create 3D model copies of each step. This is the first study to demonstrate that it is possible to create, scan, and copy stepwise, operable, patient-specific 3D-printed models, which the trainee can both reference as a 3D dissection guide and can operate on repeatedly and in any order.

Clinical situations for which 3D Printing is considered an appropriate representation or extension of data contained in a medical imaging examination: vascular conditions.

BACKGROUND: Medical three-dimensional (3D) printing has demonstrated utility and value in anatomic models for vascular conditions. A writing group composed of the Radiological Society of North America (RSNA) Special Interest Group on 3D Printing (3DPSIG) provides appropriateness recommendations for vascular 3D printing indications. METHODS: A structured literature search was conducted to identify all relevant articles using 3D printing technology associated with vascular indications. Each study was vetted by the authors and strength of evidence was assessed according to published appropriateness ratings. RESULTS: Evidence-based recommendations for when 3D printing is appropriate are provided for the following areas: aneurysm, dissection, extremity vascular disease, other arterial diseases, acute venous thromboembolic disease, venous disorders, lymphedema, congenital vascular malformations, vascular trauma, vascular tumors, visceral vasculature for surgical planning, dialysis access, vascular research/development and modeling, and other vasculopathy. Recommendations are provided in accordance with strength of evidence of publications corresponding to each vascular condition combined with expert opinion from members of the 3DPSIG. CONCLUSION: This consensus appropriateness ratings document, created by the members of the 3DPSIG, provides an updated reference for clinical standards of 3D printing for the care of patients with vascular conditions.

Computed Tomography-Based Humeral Templating for Uncemented Elbow Arthroplasty.

BACKGROUND: Intramedullary (IM) screw insertion into the distal humerus provides fixation for a novel, uncemented elbow arthroplasty. A multitude of screw sizes is required to accommodate variable humeral morphology. The goal of this study was to use computed tomography (CT) for IM screw sizing and to validate this templating by inserting screws into three-dimensionally (3D) printed models. METHODS: Computed tomography humerus scans for 30 patients were reformatted in the plane of the distal IM canal. Screw size was templated by measuring the canal diameter at 3 locations corresponding to the lengths of the screws being tested. Interrater and intrarater reliabilities of the measurements were assessed. Three-dimensional models of 5 humeri were printed, and IM screws were placed to achieve a secure endosteal fit. RESULTS: We identified combinations of body components and IM screw length and diameter for all patients to seat this uncemented elbow arthroplasty. The measurements and screw width determinations were reliable. Canal diameter correlated with age but was unrelated to sex. Screws were inserted into five 3D-printed models which matched the templates and demonstrated mechanical and radiographic evidence of secure fit. CONCLUSIONS: This study characterizes distal humerus anatomy in the context of IM screw fixation. Humerus CT scans of 30 patients were able to be templated, and validation via implantation of IM screws into 3D models was successful. Computed tomography templating will allow surgeons to predict the optimal screw size prior to implantation. A broad range of screw lengths and diameters is critical for implantation of this novel elbow arthroplasty.

Computed Tomography-Based Templating of Proximal Ulna Intramedullary Screw Fixation.

BACKGROUND: Intramedullary screw fixation of the proximal ulna can be used for fixation of the ulnar component in total elbow arthroplasty. Our purpose was to use computed tomography (CT) to characterize proximal ulna anatomy with respect to intramedullary screw fixation, and then to validate this templating process by inserting intramedullary screws into 3-dimensional (3D)-printed models. METHODS: Thirty elbow CT scans were reformatted in the axis of the proximal ulna. Screw placement was templated by fixing a length at 78 mm distal to the centerline of ulnohumeral rotation and measuring diameter, and then fixing the screw pitch diameter to 5.5 mm and measuring length. Three-dimensional models were printed for 5 patients, and intramedullary screws were advanced as distal as possible until endosteal fit was achieved. RESULTS: All patients had an anatomic limit for intramedullary screw fixation, due to dorsal angulation, varus angulation, or both. At 78 mm distal to the centerline of rotation, mean screw diameter was 5.4 mm (range, 3.2-8.0). When fixing screw diameter to 5.5 mm, the mean screw length was 79.9 mm (range, 64.2-107.9). All intramedullary screws were placed in the 3D models within 3 mm of the templated length, with correlation coefficient 0.992. CONCLUSION: This study characterized proximal ulna anatomy in the context of intramedullary screw fixation. Templating allows surgeons to predict intramedullary screw sizing, and a broad range of screw lengths and diameters is required when attempting intramedullary screw fixation for placement of the ulnar component in uncemented total elbow arthroplasty.

Use of patient-specific 3D printed models in pre-operative counseling for pediatric skull base surgery.

OBJECTIVES: Pediatric cranial base pathology is anatomically complex and surgical treatment is oftentimes difficult to conceptualize for patients and their families. Three-dimensional (3D) models of the sinuses and cranial base have the potential to enhance patient understanding in numerous domains. Our objective is to assess the use of 3D models in pre-operative parental and patient counseling prior to endoscopic endonasal skull base surgery in the pediatric population. METHODS: A survey was designed to assess parent and patient-perceived utility of 3D-printed models in surgical counseling prior to pediatric skull base surgery. RESULTS: A total of 10 patients were included. The median age was 9 years (range = 5 months-15 years). Pathology included juvenile nasopharyngeal angiofibroma (JNA) (N = 4), fibrous dysplasia of the maxilla and sphenoid (N = 1), juvenile ossifying fibroma (N = 1), nasal dermoid (N = 2, one with intracranial extension), encephalocele (N = 1), and parapharyngeal ectopic glial tissue (N = 1). Nearly all parents agreed or strongly agreed that 3D printed models were helpful in explaining the patient's skull base pathology (N = 10), surgical plan (N = 10), and possible complications (N = 9). All parents strongly agreed that 3D models should be used routinely in pre-operative counseling for endoscopic endonasal surgery. According to a majority of parents, patients older than 4 years old found the models helpful in understanding their pathology (75%) and surgery (88%). CONCLUSION: By allowing direct three-dimensional visualization of the target pathology, 3D models serve as a useful adjunct in enhancing patient comprehension of the pathologic entity, planned surgery, and potential complications prior to pediatric endoscopic endonasal skull base surgery.

Customizable document control solution for 3D printing at the point-of-care.

BACKGROUND: The rapid expansion and anticipated U.S Food and Drug Administration regulation of 3D printing at the point-of-care necessitates the creation of robust quality management systems. A critical component of any quality management system is a document control system for the organization, tracking, signature collection, and distribution of manufacturing documentation. While off-the-shelf solutions for document control exist, external programs are costly and come with network security concerns. Here, we present our internally developed, cost-effective solution for an electronic document control system for 3D printing at the point-of-care. METHODS: We created a hybrid document control system by linking two commercially available platforms, Microsoft SharePoint and Adobe Sign, using a customized document approval workflow. RESULTS: Our platform meets all Code of Federal Regulations Title 21, Part 11 guidances. CONCLUSION: Our hybrid solution for document control provides an affordable system for users to sort, manage, store, edit, and sign documents. The system can serve as a framework for other 3D printing programs to prepare for future U.S Food and Drug Administration regulation, improve the efficiency of 3D printing at the point-of-care, and enhance the quality of work produced by their respective program.

Radiological Society of North America (RSNA) 3D Printing Special Interest Group (SIG) clinical situations for which 3D printing is considered an appropriate representation or extension of data contained in a medical imaging examination: breast conditions.

The use of medical 3D printing has expanded dramatically for breast diseases. A writing group composed of the Radiological Society of North America (RSNA) Special Interest Group on 3D Printing (SIG) provides updated appropriateness criteria for breast 3D printing in various clinical scenarios. Evidence-based appropriateness criteria are provided for the following clinical scenarios: benign breast lesions and high-risk breast lesions, breast cancer, breast reconstruction, and breast radiation (treatment planning and radiation delivery).

Operable, Low-Cost, High-Resolution, Patient-Specific 3D Printed Temporal Bones for Surgical Simulation and Evaluation.

OBJECTIVES: Three-dimensional printed models created on a consumer level printer can be used to practice mastoidectomy and to discern mastoidectomy experience level. Current models in the literature for mastoidectomy are limited by expense or operability. The aims of this study were (1) to investigate the utility of an inexpensive model for mastoidectomy and (2) to assess whether the model can be used as an evaluation tool to discern the experience level of the surgeon performing mastoidectomy. METHODS: Three-dimensional printed temporal bone models from the CT scan of a 7-year old patient were created using a consumer-level stereolithography 3D printer for a raw material cost of $10 each. Mastoidectomy with facial recess approach was performed by 4 PGY-2 residents, 4 PGY-5 residents, and 4 attending surgeons on the models who then filled out an evaluation. The drilled models were collected and then graded in a blinded fashion by 6 attending otolaryngologists. RESULTS: Both residents and faculty felt the model was useful for training (mean score 4.7 out of 5; range: 4-5) and case preparation (mean score: 4.3; range: 3-5). Grading of the drilled models revealed significant differences between junior resident, senior resident, and attending surgeon scores (P = .012) with moderate to excellent interrater agreement (ICC = 0.882). CONCLUSION: The described operable model that is patient-specific was rated favorably for pediatric mastoidectomy case preparation and training by residents and faculty. The model may be used to differentiate between experience levels and has promise for use in formative and summative evaluations.

Acetabular Coverage Decreases at the End of Skeletal Growth: A 3DCT Study of Healthy Hips.

BACKGROUND: Abnormalities in size and position of the acetabulum have been linked to both developmental dysplasia of the hip and femoroacetabular impingement. Owing to its 3-dimensional (3D) complexity, plain radiography and cross-sectional studies [computed tomography (CT) and magnetic resonance imaging] have limitations in their ability to capture the complexity of the acetabular 3D anatomy. The goal of the study was to use 3D computed tomography reconstructions to identify the acetabular lunate cartilage and measure its size at varying ages of development and between sexes. METHODS: Patients aged 10 to 18 years with asymptomatic hips and a CT pelvis for appendicitis were reviewed. Patients were stratified by sex and age: preadolescent (10 to 12), young adolescent (13 to 15), and old adolescent (16 to 18) in equal proportions. Materialise 3-matic was used to generate a 3D pelvic model, and the acetabular lunate cartilage surface area was calculated. The lunate cartilage was divided into anatomic segments: superior (11:00 to 1:00), anterior (1:00 to 4:00), and posterior (8:00 to 11:00). The femoral head surface area was calculated to control for patient size. Mixed effects models were generated predicting segment size where side was treated as a repeated measure. Absolute and relative (lunate cartilage to femoral head) models were generated. RESULTS: Sixty-two patients (124 hips) were included. Females showed a significant decrease in femoral head coverage as age increased overall and in the 3 subsegments. The majority of changes occurred between the preadolescent and young adolescent groups. Males did not show an overall change, but the superior and anterior anatomic subgroups showed a significant decrease in coverage between the young and old adolescent groups. Male lunate cartilages were absolutely, but not relatively, larger than females. No clinically significant side-to-side differences were noted. CONCLUSIONS: The relative femoral head coverage by the acetabular lunate cartilage reduced with increasing age, suggesting the growth of the femoral head outpaces the acetabular lunate cartilage's growth. This was more prominent in females. This study has important implications for expected acetabular coverage changes in the latter aspects of pediatric and adolescent development. LEVEL OF EVIDENCE: Level III-diagnostic study.

Yttrium-90 Radioembolization Is Cost Effective in Intrahepatic Cholangiocarcinoma: A SEER Medicare Population Study.

PURPOSE: To analyze the cost-effectiveness of radioembolization in the treatment of intrahepatic cholangiocarcinoma (ICC) using the Surveillance, Epidemiology, and End Results (SEER) Medicare cancer database. MATERIALS AND METHODS: Cost as measured by total treatment-related reimbursement in patients diagnosed with ICC who received chemotherapy alone or chemotherapy and yttrium-90 radioembolization was assessed in the SEER Medicare cancer database (1999-2012). Survival analysis was performed, and incremental cost-effectiveness ratios were generated. RESULTS: The study included 585 patients. Average age at diagnosis was 71 years (standard deviation: 9.9), and 52% of patients were male. Twelve percent of patients received chemotherapy with radioembolization (n = 72), and 88% of patients (n = 513) received only chemotherapy. Median survival was 1043 days (95% confidence interval [CI]: 894-1244) for chemotherapy plus radioembolization and 811 days (95% CI: 705-925) for chemotherapy alone (P = .02). Patients who received combination therapy were slightly younger (71 vs 69 years, P = .03). No significant differences were observed between treatment groups in age at treatment, sex, race, or city size. Multivariable analysis showed a hazard ratio for progression for combination therapy versus chemotherapy alone of 0.76 (95% CI: 0.59-0.97, P = .029). The incremental cost-effectiveness ratio, a measure of cost of each added year of life, was $50,058.65 per year (quartiles: $11,454.63, $52,763.28). CONCLUSIONS: Combination therapy of ICC with chemotherapy and radioembolization is associated with higher median survival and can be a cost-effective treatment, with a median cost of $50,058.65 per additional year of survival.

Evaluation of 3D Printed Temporal Bone Models in Preparation for Middle Cranial Fossa Surgery.

HYPOTHESIS: Patient-specific 3D printed models are useful presurgical planning tools because they accurately represent the anatomy and drilling characteristics of the middle cranial fossa (MCF) approach to the internal auditory canal (IAC). BACKGROUND: The MCF approach to the IAC can be challenging due to variability of the bony architecture along the floor of the middle fossa. Patient-specific 3D printed models may enhance surgeon knowledge of a given patient's anatomy when preparing for MCF surgery. METHODS: Six temporal bone models were printed from photoacrylic resin based on CT data obtained from cadaveric specimens using a desktop stereolithography 3D printer. Critical structures to avoid injuring, the facial nerve and membranous labyrinth, were modeled as hollow cavities and filled with indicator paint. Two neurotologists each drilled three 3D printed models and the corresponding cadaveric specimens, and then completed a 41-item visual analog scale questionnaire (score range of each item: 0-10) to assess the model's accuracy, utility, and potential as a training tool. RESULTS: Drilling the model was favorably rated (median score 9.2; range 7.3-9.6) for its ability to provide surgeons with an accurate mental image of the corresponding cadaveric anatomy. Overall similarity of feel of drilling the model in comparison to human bone was moderate (median 7.6; range 6.6-9.0). Surgeons would use this model to prepare for future cases (median 9.4; range 5.1-9.9) and felt it had excellent utility for training purposes (median 9.3; range 8.4-9.9). CONCLUSIONS: Patient-specific 3D printed models provide an anatomically accurate and favorable tool for preparing for MCF surgery.

3-Dimensional Printed Models May Be a Useful Tool When Planning Revision Anterior Cruciate Ligament Reconstruction.

PURPOSE: To determine whether using 3-dimensional (3D)-printed models in addition to computed tomography (CT) scans to evaluate the primary femoral and tibial tunnels before revision anterior cruciate ligament (ACL) reconstruction leads to better agreement with the surgical approach than CT alone. METHODS: Fifteen patients who underwent revision ACL reconstruction were retrospectively identified. The mean age was 24.3 years, and 73% were female. Using only CT images, 3 board-certified orthopaedists and 5 sports medicine orthopaedic fellows evaluated whether the existing tibial and femoral tunnels were acceptable for the revision surgery. Subsequently, 3D-printed models were made available in addition to the CT scan, and the same questions were asked. RESULTS: For the attending orthopaedic physicians, adding the 3D-printed models did not have a significant impact on the tibial or femoral tunnel agreement compared with the surgical approach. With the fellow physicians, however, using the 3D-printed models with tibial tunnel evaluation led to a higher agreement rate (76%) compared with CT images alone (63%) (P = .050). Furthermore, with the fellow physicians, there was a higher overall agreement when evaluating both the tibial and femoral tunnels with the addition of 3D-printed models (74%) compared with CT alone (65%) (P = .049). CONCLUSION: Our hypothesis that using 3D-printed models leads to better agreement with the surgical approach was unsupported based on the response of the board-certified orthopaedists. Based on the fellow response, it stands to reason that 3D-printed models may be a useful tool in understanding spatial orientation when planning for revision ACL surgery. LEVEL OF EVIDENCE: IV, retrospective case series.

Safety of Drilling 3-Dimensional-Printed Temporal Bones.

Importance: Three-dimensional (3-D) printing of temporal bones is becoming more prevalent. However, there has been no measure of the safety of drilling these models to date. It is unknown whether the heat and sheer from the drill may create harmful volatile organic compounds (VOCs). Objective: To determine the level of exposure to airborne contaminants when conducting high-speed drilling on 3-D-printed models and to explore whether there is a need for exposure control measures. Design, Setting, and Participants: In this occupational safety assessment carried out in a temporal bone laboratory, 3 individual 3-D-printed temporal bones were made using 3 different materials commonly cited in the literature: polylactic acid (PLA), photoreactive acrylic resin (PAR), and acrylonitrile butadiene styrene (ABS). Each model was drilled for 40 minutes while the surgeon wore a sampling badge. Sampling was conducted for airborne concentrations of VOCs and total particulate (TP). Monitoring for VOCs was conducted using Assay Technology 521-25 organic vapor badge worn at the surgeon's neckline. Monitoring for TP was conducted using a polyvinyl chloride filter housed inside a cassette and coupled with an SKC AirChek 52 personal air-sampling pump. Samples were collected and analyzed in accordance with NIOSH Method 500. Main Outcomes and Measures: Presence of VOCs and TP count exposures at Occupational Safety and Health Administration (OSHA) actionable levels. Results: Results of the VOC sample were less than detection limits except for isopropyl alcohol at 0.24 ppm for PAR. The TP samples were less than the detection limit of 1.4 mg/m3. The results are below all applicable OSHA Action Levels and Permissible Exposure Limits for all contaminants sampled for. Conclusions and Relevance: Drilling 3-D-printed models made from PLA, ABS, and PAR was safe by OSHA standards. Continued monitoring and safety testing are needed as 3-D-printed technologies are introduced to our specialty.

Sestamibi SPECT/CT versus SPECT only for preoperative localization in primary hyperparathyroidism: a single institution 8-year analysis.

BACKGROUND: Primary hyperparathyroidism is caused by single gland disease in 85% of cases and by multiglandular disease in 15%. Our aim was to discover if the addition of computed tomography acquisition/fusion on a hybrid scanner to traditional dual-phase single-photon emission tomography improves localization accuracy. METHODS: A prospective database was queried for the perioperative data of patients with sporadic primary hyperparathyroidism who had initial exploration from 2006-2014 with ≥6 month follow-up to define anatomy. Prior to 2010, patients had single-photon emission tomography (n = 633); after 2010, they had single-photon emission tomography/computed tomography (n= 755). RESULTS: In 1,388 patients, the rates of single gland disease (P=.8), bilateral exploration (P=.4), and negative imaging (145 patients, P=.33) were equal between imaging cohorts. In 1,186 patients with single gland disease, the positive predictive value of single-photon emission tomography/computed tomography was somewhat greater (90% vs 85%) and the accuracy of single-photon emission tomography/computed tomography was superior (83% vs 77%, P=.02). In the 202 patients with multiglandular disease, 20% had negative imaging results with no difference by type (single-photon emission tomography/computed tomography 17%, single-photon emission tomography 23%, P=.3), but single-photon emission tomography/computed tomography was more accurate (36%) than single-photon emission tomography (22%, P=.04) in predicting multiglandular disease. CONCLUSION: In a large cohort study of patients with sporadic primary hyperparathyroidism undergoing parathyroidectomy, positive single-photon emission tomography/computed tomography results provided more reliable operative guidance than single-photon emission tomography for both single gland disease and multiglandular disease.

Apparent Diffusion Coefficient (ADC) of the vitreous humor and Susceptibility Weighted Imaging (SWI) of the retina in abused children with retinal hemorrhages.

This study speculated that the apparent diffusion coefficient (ADC) of the vitreous humor might be altered in the setting of abusive head trauma (AHT) with retinal hemorrhages (RH). Fourty-four subjects were analyzed (n=20 AHT cases; n=24 controls). There was no statistically significant difference in normalized ADC values between the cases and controls (-0.14 and -0.08 respectively, p=0.46), but analysis of RH by susceptibility weighted imaging (SWI) compared to dilated funduscopic exam demonstrated statistically significant correlation (p=0.003 and 0.012). Our results suggest that SWI serves as a more sensitive diagnostic tool for detection of ocular injury in AHT than ADC.

Connecting cancer biology and clinical outcomes to imaging in KRAS mutant and wild-type colorectal cancer liver tumors following selective internal radiation therapy with yttrium-90.

PURPOSE: To determine whether pathologic colorectal tumor KRAS mutation status is correlated with progression-free survival (PFS) by imaging after selective internal radiation therapy with Yttrium-90 (SIRT Y90) for metastatic colorectal cancer in the liver (mCRC). MATERIALS AND METHODS: This was an IRB approved, HIPAA compliant retrospective cohort study. Consecutive patients with unresectable mCRC with documented KRAS mutation status treated at a single center from 2002 to 2013 with SIRT Y90 were investigated. Treatment response was compared between KRAS wild-type (wt) and mutant (mut) using an anatomic tumor response criteria based on RECIST 1.0. Kaplan-Meier estimation and Cox regression analysis were used to measure progression-free survival (PFS) and to assess independent prognostic factors for PFS. RESULTS: 82 of 186 patients met review criteria. 33 (40.2%) patients were identified as KRAS mut. PFS was longer in KRAS wt (median 166 days [95% CI 96-258 days]) vs. mut (median 91 days [95% CI 79-104 days], p = 0.002). KRAS mut patients were 1.48 times more likely to progress at first follow-up imaging than wt (95% CI 1.06-2.08, p = 0.024). Univariate analysis identified high pre-SIRT Y90 INR, KRAS wt, any use of anti-EGFR therapy, and post-SIRT Y90 chemotherapy as prognostic factors for longer PFS. In multivariate analysis, only KRAS wt was an independent prognostic factor for longer PFS (RR: 1.80 [95% CI 1.08-2.99], p = 0.024). CONCLUSION: Longer PFS is associated with KRAS wt vs. mut following SIRT Y90.

Comparison of true unenhanced and virtual unenhanced (VUE) attenuation values in abdominopelvic single-source rapid kilovoltage-switching spectral CT.

OBJECTIVE: To assess the agreement between the true non-contrast (TNC) attenuation values of intra-abdominal structures and attenuation values obtained on virtual-unenhanced (VUE) images based on rapid kVp-switching dual-energy CT. The effects of contrast phase and patient characteristics (e.g., BMI, hematocrit, hemoglobin content) on VUE values were also investigated. METHODS: Ninety four patients who underwent triphasic abdominal CT (liver mass protocol, n = 47; pancreas mass protocol, n = 47) between August 2014 and May 2015 were retrospectively reviewed. Unenhanced series was performed using conventional single-energy mode at 120 kVp. Late arterial and venous phase post-contrast series were obtained utilizing rapid kVp-switching dual-energy CT technique. VUE images were processed off of arterial (VUE-art) and venous (VUE-ven) phase series. Attenuation values of liver, pancreas, kidneys, adrenal glands, muscle, subcutaneous fat, aorta, IVC, and main portal vein were recorded on TNC and VUE sets of images. Attenuation values were compared using univariate linear regression and Student two-tailed paired t test. RESULTS: There was excellent correlation between TNC, VUE-art, and VUE-ven attenuation values across all organs (p < 0.0001). Paired Student t test, however, showed significant difference between TNC and VUE-art attenuation of kidneys, right adrenal gland, paraspinal muscle, and aorta. There was also significant difference between TNC and VUE-ven attenuation of left kidney. Percentage of cases which had >10 HU difference between VUE and TNC for an individual was calculated which ranged between 13% (right kidney) and 42% (right adrenal gland). CONCLUSION: Although the correlation between VUE and TNC attenuation values was excellent and mean difference between TNC and VUE attenuation values was negligible (ranging between -5.94 HU for paraspinal muscles to 6.2 HU in aorta), intra-patient analysis showed a considerable number of cases which had >10 HU difference between VUE and TNC. VUE-ven generally offered a better approximation of TNC values. Further optimization of post-processing algorithms might be necessary before complete replacement of TNC with VUE images.

Lumbar Transforaminal Epidural Steroid Injections: Incidental Extraspinal Findings on Planning Imaging.

OBJECTIVE: Planning imaging performed during CT-guided procedures may occasionally contain important incidental findings. The purpose of this study was to identify and characterize by clinical relevance the extraspinal findings detected on planning imaging for CT-guided lumbar transforaminal epidural steroid injections (TFESIs). MATERIALS AND METHODS: Four radiologists retrospectively evaluated the planning scout views and CT studies for 488 consecutive CT-guided lumbar TFESIs performed in 400 patients over a 1-year period. Incidental extraspinal findings were identified and used to characterize patients by the need for follow-up using the CT Colonography Reporting and Data System (C-RADS), a classification scheme originally developed to characterize incidental findings on CT colonography. Patients with C-RADS E4 findings have potentially important findings that should be communicated to the referring physician; patients with C-RADS E3 findings have findings that are likely unimportant, but workup may be indicated. All previously unknown C-RADS E3 and E4 findings discovered in the course of this research were reported to referring physicians for appropriate patient follow-up. RESULTS: Ten of 400 (2.5%) patients were classified as C-RADS E4; the most common C-RADS E4 finding was vascular aneurysm or stenosis (4/400, 1.0%). Thirteen of 400 (3.3%) patients were classified as C-RADS E3; the most common C-RADS E3 finding was hepatomegaly (4/400, 1.0%). Of 22 patients with C-RADS E3 and E4 findings unknown to clinicians, the finding for only one (4.5%) was communicated to clinicians at the time of the procedure. CONCLUSION: Clinically important incidental extraspinal findings were identified in 5.8% of patients on the planning imaging performed for CT-guided lumbar TFESIs. Communication of clinically important findings was poor (4.5%).

Lung Shunt Fraction prior to Yttrium-90 Radioembolization Predicts Survival in Patients with Neuroendocrine Liver Metastases: Single-Center Prospective Analysis.

OBJECTIVE: To investigate survival outcomes following radioembolization with Yttrium-90 (Y90) for neuroendocrine tumor liver metastases (NETLMs). This study was designed to assess the efficacy of Y90 radioembolization and to evaluate lung shunt fraction (LSF) as a predictor for survival. METHODS: A single-center, prospective study of 44 consecutive patients (median age: 58.5 years, 29.5 % male) diagnosed with pancreatic (52.3 %) or carcinoid (47.7 %) NETLMs from 2006 to 2012 who underwent Y90 radioembolization was performed. Patients' baseline characteristics, including LSF and median overall survival (OS) from first Y90 radioembolization, were recorded and compared between patients with high (≥10 %) and low (<10 %) LSF. Baseline comparisons were performed using Fisher's exact tests for categorical and Mann-Whitney U test for continuous variables. Survival was calculated using the Kaplan-Meier method. Univariate (Wilcoxon rank-sum test) and multivariate analyses (Cox Proportional Hazard Model) for risk factor analysis were performed. RESULTS: There was no statistically significant difference in age, gender, race, tumor properties, or previous treatments between patients with high (n = 15) and low (n = 29) LSF. The median OS was 27.4 months (95 %CI 12.73-55.23), with 4.77 months (95 %CI 2.87-26.73) for high and 42.77 months (95 %CI 18.47-59.73) for low LSF (p = 0.003). Multivariate analysis identified high LSF (p = 0.001), total serum bilirubin >1.2 mg (p = 0.016), and lack of pretreatment with octreotide (p = 0.01) as independent prognostic factors for poorer survival. Tumor type and total radiation dose did not predict survival. CONCLUSIONS: LSF ≥10 %, elevated bilirubin levels, and lack of pretreatment with octreotide were found to be independent prognostic factors for poorer survival in patients with NETLMs.

Extraforaminal needle tip position reduces risk of intravascular injection in CT-fluoroscopic lumbar transforaminal epidural steroid injections.

BACKGROUND: Lumbar transforaminal epidural steroid injection is a common and effective tool for managing lumbar radicular pain, although accidental intravascular injection can rarely result in paralysis. The purpose of this study is to determine the safest needle tip position for computed tomography (CT)-guided lumbar transforaminal epidural steroid injections as determined by incidence of intravascular injection. METHODS: Three radiologists, in consensus, reviewed procedural imaging for consecutive CT-fluoroscopic lumbar transforaminal epidural steroid injections performed during a 16-month period. Intravascular injections were identified and categorized by needle tip position, vessel type injected, intravascular injection volume and procedural phase containing the intravascular injection. Pearson chi-square and logistic regression testing were used to assess differences between groups, as appropriate. RESULTS: Intravascular injections occurred in 9% (52/606) of injections. The intravascular injection rate was significantly lower (P<0.001) for extraforaminal needle position (0%, 0/109) compared to junctional (8%, 27/319) and foraminal (14%, 25/178) needle tip positions. Of the intravascular injections, 4% (2/52) were likely arterial, 35% (18/52) were likely venous, and 62% (32/52) were indeterminate for vessel type injected. 46% (24/52) of intravascular injections were large volume, 33% (17/52) were small volume, and 21% (11/52) were trace volume. 56% (29/52) of intravascular injections occurred with the contrast trial dose, 29% (15/52) with the steroid/analgesic cocktail, and 15% (8/52) with both. CONCLUSIONS: An extraforaminal needle position for CT-fluoroscopic lumbar transforaminal epidural steroid injections decreases the risk of intravascular injection and therefore may be safer than other needle tip positions.