A Single-Center Experience with a Shear-Thinning Conformable Embolic.

The purpose of this study was to evaluate the technical success, effectiveness, and safety of transarterial embolization for acute bleeding management with a shear-thinning conformable embolic. This single-center retrospective study evaluated outcomes after embolization using Obsidio conformable embolic (OCE). Technical success was defined as performing transarterial embolization within the target vessel to complete stasis of antegrade flow. Treatment effectiveness was defined as cessation of bleeding for patients. Eleven patients underwent 11 embolization procedures. A total of 16 arteries were embolized. Indications for embolization were spontaneous tumor bleeding (6/11), hematuria (2/11), active duodenal bleeding (1/11), portal hypertensive bleeding (1/11), and rectus sheath hematoma (1/11). The technical success rate was 100%. The median vessel diameter was 2 mm (range, 1-3 mm). There were no adverse events or off-target embolization. OCE demonstrated technical success and treatment effectiveness with a short-term safety profile for transarterial embolization interventions.

Implications for high-precision dose radiation therapy planning or limited surgical resection after percutaneous computed tomography-guided lung nodule biopsy using a tract sealant.

PURPOSE: Precision radiation therapy such as stereotactic body radiation therapy and limited resection are being used more frequently to treat intrathoracic malignancies. Effective local control requires precise radiation target delineation or complete resection. Lung biopsy tracts (LBT) on computed tomography (CT) scans after the use of tract sealants can mimic malignant tract seeding (MTS) and it is unclear whether these LBTs should be included in the calculated tumor volume or resected. This study evaluates the incidence, appearance, evolution, and malignant seeding of LBTs. METHODS AND MATERIALS: A total of 406 lung biopsies were performed in oncology patients using a tract sealant over 19 months. Of these patients, 326 had follow-up CT scans and were included in the study group. Four thoracic radiologists retrospectively analyzed the imaging, and a pathologist examined 10 resected LBTs. RESULTS: A total of 234 of 326 biopsies (72%, including primary lung cancer [n = 98]; metastases [n = 81]; benign [n = 50]; and nondiagnostic [n = 5]) showed an LBT on CT. LBTs were identified on imaging 0 to 3 months after biopsy. LBTs were typically straight or serpiginous with a thickness of 2 to 5 mm. Most LBTs were unchanged (92%) or decreased (6.3%) over time. An increase in LBT thickness/nodularity that was suspicious for MTS occurred in 4 of 234 biopsies (1.7%). MTS only occurred after biopsy of metastases from extrathoracic malignancies, and none occurred in patients with lung cancer. CONCLUSIONS: LBTs are common on CT after lung biopsy using a tract sealant. MTS is uncommon and only occurred in patients with extrathoracic malignancies. No MTS was found in patients with primary lung cancer. Accordingly, potential alteration in planned therapy should be considered only in patients with LBTs and extrathoracic malignancies being considered for stereotactic body radiation therapy or wedge resection.

MRI-Guided Interventions in Musculoskeletal System.

Image-guided interventions in the musculoskeletal system require accurate detection and characterization of lesions involving bone and soft tissues. Magnetic resonance imaging (MRI) has superior soft tissue contrast resolution particularly in bone and soft tissues where computed tomography and ultrasonography have significant limitations. In addition, the multiplanar imaging capabilities of MRI facilitate targeting lesions and tracking interventional devices. Although conventional diagnostic MRI sequences suffer from motion sensitivity and prolonged imaging time, recently developed fast imaging sequences allow for rapid acquisition of high-quality images, rendering MRI more suitable for image-guided interventions. Although computed tomography and ultrasonography still dominate the spectrum of image-guided interventions in the musculoskeletal system, many MRI-guided procedures have been developed and are well established in routine clinical work. In addition, new techniques and novel MRI-guided applications are being developed to address complex clinical problems in a minimally invasive fashion.

Impact of an inferior vena cava filter retrieval algorithm on filter retrieval rates in a cancer population.

OBJECTIVE: Our primary purpose was to assess the impact of an inferior vena cava filter retrieval algorithm in a cancer population. Because cancer patients are at persistently elevated risk for development of venous thromboembolism (VTE), our secondary purpose was to assess the incidence of recurrent VTE in patients who underwent filter retrieval. METHODS: Patients with malignant disease who had retrievable filters placed at a tertiary care cancer hospital from August 2010 to July 2014 were retrospectively studied. A filter retrieval algorithm was established in August 2012. Patients and referring physicians were contacted in the postintervention period when review of the medical record indicated that filter retrieval was clinically appropriate. Patients were classified into preintervention (August 2010-July 2012) and postintervention (August 2012-July 2014) study cohorts. Retrieval rates and clinical pathologic records were reviewed. RESULTS: Filter retrieval was attempted in 34 (17.4%) of 195 patients in the preintervention cohort and 66 (32.8%) of 201 patients in the postintervention cohort (P < .01). The median time to filter retrieval in the preintervention and postintervention cohorts was 60 days (range, 20-428 days) and 107 days (range, 9-600 days), respectively (P = .16). In the preintervention cohort, 49 of 195 (25.1%) patients were lost to follow-up compared with 24 of 201 (11.9%) patients in the postintervention cohort (P < .01). Survival was calculated from the date of filter placement to death, when available. The overall survival for patients whose filters were retrieved was longer compared with the overall survival for patients whose filters were not retrieved (P < .0001). Of the 80 patients who underwent successful filter retrieval, two patients (2.5%) suffered from recurrent VTE (n = 1 nonfatal pulmonary embolism; n = 1 deep venous thrombosis). Both patients were treated with anticoagulation without filter replacement. CONCLUSIONS: Inferior vena cava filter retrieval rates can be significantly increased in patients with malignant disease with a low rate (2.5%) of recurrent VTE after filter retrieval.

Multiple Renal Artery Pseudoaneurysms in Patients Undergoing Renal Artery Embolization Following Partial Nephrectomy: Correlation with RENAL Nephrometry Scores.

PURPOSE: To describe the incidence of multiple renal artery pseudoaneurysms (PSA) in patients referred for renal artery embolization following partial nephrectomy and to study its relationship to RENAL nephrometry scores. MATERIALS AND METHODS: The medical records of 25 patients referred for renal artery embolization after partial nephrectomy were retrospectively reviewed for the following parameters: size and number of tumors, RENAL nephrometry scores, angiographic abnormalities, technical and clinical outcomes, and estimated glomerular filtration rates (eGFRs) after embolization. RESULTS: Twenty-four patients had primary renal tumors, while 1 patient had a pancreatic tumor invading the kidney. Multiple tumors were resected in 4 patients. Most patients (92 %) were symptomatic, presenting with gross hematuria, flank pain, or both. Angiography revealed PSA with (n = 5) or without (n = 20) AV fistulae. Sixteen patients (64 %) had multiple PSA involving multiple renal vessels. Higher RENAL nephrometry scores were associated with an increasing likelihood of multiple PSA. Multiple vessels were embolized in 14 patients (56 %). Clinical success was achieved after one (n = 22) or two (n = 3) embolization sessions in all patients. Post-embolization eGFR values at different time points after embolization were not significantly different from the post-operative eGFR. CONCLUSION: A majority of patients requiring renal artery embolization following partial nephrectomy have multiple pseudoaneurysms, often requiring selective embolization of multiple vessels. Higher RENAL nephrometry score is associated with an increasing likelihood of multiple pseudoaneurysms. We found transarterial embolization to be a safe and effective treatment option with no long-term adverse effect on renal function in all but one patient with a solitary kidney.

Efficacy of a Self-expanding Tract Sealant Device in the Reduction of Pneumothorax and Chest Tube Placement Rates After Percutaneous Lung Biopsy: A Matched Controlled Study Using Propensity Score Analysis.

PURPOSE: To evaluate the use of a self-expanding tract sealant device (BioSentry™) on the rates of pneumothorax and chest tube insertion after percutaneous lung biopsy. MATERIALS AND METHODS: In this retrospective study, we compared 318 patients who received BioSentry™ during percutaneous lung biopsy (treated group) with 1956 patients who did not (control group). Patient-, lesion-, and procedure-specific variables, and pneumothorax and chest tube insertion rates were recorded. To adjust for potential selection bias, patients in the treated group were matched 1:1 to patients in the control group using propensity score matching based on the above-mentioned variables. Patients were considered a match if the absolute difference in their propensity scores was ≤equal to 0.02. RESULTS: Before matching, the pneumothorax and chest tube rates were 24.5 and 13.1% in the control group, and 21.1 and 8.5% in the treated group, respectively. Using propensity scores, a match was found for 317 patients in the treatment group. Chi-square contingency matched pair analysis showed the treated group had significantly lower pneumothorax (20.8 vs. 32.8%; p = 0.001) and chest tube (8.2 vs. 20.8%; p < 0.0001) rates compared to the control group. Sub-analysis including only faculty who had >30 cases of both treatment and control cases demonstrated similar findings: the treated group had significantly lower pneumothorax (17.6 vs. 30.2%; p = 0.002) and chest tube (7.2 vs. 18%; p = 0.001) rates. CONCLUSIONS: The self-expanding tract sealant device significantly reduced the pneumothorax rate, and more importantly, the chest tube placement rate after percutaneous lung biopsy.

Standardized Reporting in IR: A Prospective Multi-Institutional Pilot Study.

PURPOSE: To assess adoption and survey-based satisfaction rates following deployment of standardized interventional radiology (IR) procedure reports across multiple institutions. MATERIALS AND METHODS: Standardized reporting templates for 5 common interventional procedures (central venous access, inferior vena cava [IVC] filter insertion, IVC filter removal, uterine artery embolization, and vertebral augmentation) were distributed to 20 IR practices in a prospective quality-improvement study. Participating sites edited the reports according to institutional preferences and deployed them for a 1-year pilot study concluding in July 2015. Study compliance was measured by sampling 20 reports of each procedure type at each institution, and surveys of interventionalists and referring physicians were performed. Modifications to the standardized reporting templates at each site were analyzed. RESULTS: Ten institutions deployed the standardized reports, with 8 achieving deployment of 3-12 months. The mean report usage rate was 57%. Each site modified the original reports, with 26% mean reduction in length, 18% mean reduction in wordiness, and 60% mean reduction in the number of forced fill-in fields requiring user input. Linear-regression analysis revealed that reduced number of forced fill-in fields correlated significantly with increased usage rate (R2 = 0.444; P = .05). Surveys revealed high satisfaction rates among referring physicians but lower satisfaction rates among interventional radiologists. CONCLUSIONS: Standardized report adoption rates increased when reports were simplified by reducing the number of forced fill-in fields. Referring physicians preferred the standardized reports, whereas interventional radiologists preferred standard narrative reports.

The Effect of Needle Gauge on the Risk of Pneumothorax and Chest Tube Placement After Percutaneous Computed Tomographic (CT)-Guided Lung Biopsy.

BACKGROUND: The aim of this study was to evaluate the effect of coaxial guide needle gauge (18 vs. 19 gauge) on the risk of pneumothorax and chest tube placement after CT-guided lung biopsy. METHODS: Imaging records of all patients who had undergone CT-guided lung biopsies at our institution from March 1, 2006 to December 9, 2010 were retrospectively reviewed. Univariate and multivariate logistic regression analyses were performed to assess the effect of various patient-, lesion-, and procedure-related variables on subsequent pneumothorax and chest tube placement rates. RESULTS: The study included 4262 biopsies (2304 with 18-gauge and 1958 with 19-gauge coaxial guide needles) in 3917 patients. The rates of pneumothorax and chest tube placement were 30.2 and 15%, respectively. Pneumothorax occurred in 35% of procedures performed with 18-gauge needles and in 24.5% of procedures performed with 19-gauge needles (p < 0.0001). Chest tube insertion occurred in 16.7% of procedures performed with 18-gauge needles and in 13.1% of procedures performed with 19-gauge needles (p = 0.0011). Multivariate logistic regression models demonstrated that the use of an 18-gauge needle was associated with a higher rate of pneumothorax (p < 0.0001) and chest tube placement (p = 0.0003). The following factors were also associated with higher rates of pneumothorax and chest tube placement: older age, emphysema, greater number of pleural surfaces crossed, and a longer biopsy needle path length. CONCLUSIONS: The use of a 19-gauge coaxial guide needle significantly decreases the risk of pneumothorax and chest tube placement compared with an 18-guage needle.

Real-time magnetic resonance imaging-guided cryoablation of small renal tumors at 1.5 T.

OBJECTIVES: Real-time magnetic resonance imaging (MRI)-guided cryoablation has been investigated in open MRI systems with low magnetic fields (0.2-0.5 T). More advanced imaging techniques and faster imaging rates are possible at higher magnetic fields, which often require a closed-bore magnet design. However, there is very little experience with real-time interventions in closed-bore 1.5-T MRI units. Herein, we report our initial experience with real-time MRI-guided cryoablation of small renal tumors using a prototype balanced steady-state free precession imaging sequence in a closed-bore 1.5-T MRI system. MATERIALS AND METHODS: From August 2008 to April 2012, 18 patients underwent MRI-guided cryoablation of small renal tumors. A 1.5-T cylindrical MRI scanner with a 125 cm × 70 cm bore and a prototype balanced steady-state free precession sequence (BEAT interactive real-time tip tracking) were used to guide the placement of 17-gauge cryoprobes in real time. Ice ball formation was monitored every 3 minutes in 1 or more imaging planes. Each ablation consisted of 2 freeze-thaw cycles. Contrast-enhanced MRI was performed after the second active thaw period. Follow-up consisted of clinical evaluation and renal protocol computed tomography (CT) or MRI performed at 1, 6, 12, 18, and 24 months and annually thereafter. RESULTS: During the study period, we successfully ablated 18 tumors in 18 patients in 18 sessions. The mean tumor size was 2.2 cm (median, 2 cm; range, 1.2-4.4 cm). The number of cryoprobes used per patient was determined based on tumor size. The mean number of cryoprobes used per patient was 3 (median, 3 cryoprobes; range, 2-4 cryoprobes). Fifty-six cryoprobes, 9 biopsy needles, and 2 hydrodissection needles were successfully placed under real-time MRI guidance using BEAT interactive real-time tip tracking sequence. Hydrodissection under MRI guidance was successfully performed in 4 patients. In each patient, contrast-enhanced MRI performed after the second active thaw period revealed a sharply defined avascular zone surrounding the targeted tumor, which confirmed complete ablation of the tumor with adequate margins. Although contrast media slowly accumulated in the targeted tumor in 9 patients immediately after the procedure, follow-up imaging studies performed at a mean of 16.7 months revealed no contrast enhancement within the ablation zone in these patients. Disease-specific, metastasis-free, and local recurrence-free survival rates were all 100%. CONCLUSIONS: Real-time placement and manipulation of cryoprobes during MRI-guided cryoablation of small renal tumors in a closed-bore, high-magnetic field scanner are feasible. Technical and clinical success rates are similar to those of patients who undergo CT-guided radiofrequency ablation or cryoablation of small renal tumors. Our findings suggest that MRI-guided ablation has several advantages over CT-guided ablation, including real-time guidance for probe placement, multiplanar imaging, exquisite soft tissue contrast, and lack of ionizing radiation.

Magnetic resonance imaging-guided biopsy in the musculoskeletal system using a cylindrical 1.5-T magnetic resonance imaging unit.

OBJECTIVES: The objective of this study was to report a single-center experience with magnetic resonance imaging (MRI)-guided biopsy in the musculoskeletal system using a closed-bore, cylindrical, high-magnetic-field (1.5-T) MRI unit. METHODS: From May 2010 to July 2011, 100 consecutive MRI-guided biopsy sessions were undertaken for musculoskeletal lesions in 97 patients. Patient demographics, tumor characteristics, and biopsy techniques were recorded. Biopsy results, treatment outcomes, and follow-up imaging studies were reviewed. RESULTS: Biopsy procedures were technically successful in 99 cases (99%). Despite a mean body mass index of 30 kg/m, all patients fit within the bore of the magnet. There were 69 soft-tissue and 31 bone tumors. Most patients had both tissue core (n = 93) and fine-needle aspiration (n = 84) biopsies. All lesions were adequately imaged, localized, and targeted using rapid balanced steady-state free precession imaging (89%), fast T1 (4%), or combination of the 2 techniques (7%). A prototype real-time imaging sequence was used in 29 cases (29%) to guide biopsy needle insertion. There were no major complications. Sensitivity, specificity, and overall accuracy were 97%, 100%, and 97.6%, respectively. CONCLUSIONS: Magnetic resonance imaging-guided biopsy in a closed-bore, high-field-strength magnet is a safe, easy, and effective technique for evaluation of musculoskeletal lesions. Ideally, the MRI suite should be equipped with an in-room radiofrequency-shielded monitor and a communication system. However, surface coils with adequate opening to grant access to the biopsy site, MRI-compatible needles, and MRI-compatible patient monitoring devices are absolutely necessary to perform MRI-guided biopsies.

Response, survival, and prognostic factors after hepatic arterial chemoembolization in patients with liver metastases from cutaneous melanoma.

We reviewed the medical records of 42 patients with cutaneous melanoma metastatic to the liver who underwent hepatic artery chemoembolization (HACE) at our institution. HACE resulted in radiologic response (38.9%) or disease stabilization (47.2%) in most patients. The median overall survival (OS) and time to progression (TTP) of liver disease were 7.7 and 6 months, respectively. Patient's age, lactate dehydrogenase (LDH) levels, type of treatment, number of extrahepatic metastatic sites, and response to therapy were found to be significant predictors of OS after HACE. Prolonged survival was seen in patients who responded to HACE (p = .034).

Characterization of contrast enhancement in the ablation zone immediately after radiofrequency ablation of renal tumors.

PURPOSE: To characterize the degree of contrast enhancement within the ablation zone immediately after radiofrequency (RF) ablation of renal tumors. MATERIALS AND METHODS: Patients with renal tumors treated with percutaneous RF ablation at one institution between January 2004 and October 2007 were retrospectively reviewed. For each tumor, computed tomography (CT) density measurements were made at four phases (noncontrast, arterial phase, parenchymal phase, and excretory phase) in each of four CT examinations (before ablation, day 0, 1 month, and 6 months). RESULTS: A total of 36 renal tumors in 34 patients were treated with CT-guided RF ablation in 35 sessions. Before RF ablation, all tumors exhibited enhancement after intravenous administration of contrast material. The peak density was reached during the parenchymal phase, with a partial washout of contrast agent in the excretory phase. On CT images acquired immediately after RF ablation (day 0), 28 of the 36 ablated tumors (78%) exhibited clinically significant homogeneous enhancement (ie, density change >10 HU) within the ablation zone. However, contrast-enhanced CT studies performed at 1 and 6 months revealed no clinically significant enhancements in any of the 36 treated tumors (mean density changes of 4 HU at 1 month and 3 HU at 6 months). CONCLUSIONS: Contrast-enhanced CT studies revealed a mild, temporary homogenous contrast enhancement of the ablation zone immediately after RF ablation of renal tumors, which should not be mistaken for a residual, unablated tumor. This enhancement in the ablation zone eventually disappears in follow-up contrast-enhanced CT studies.

Preclinical assessment of a 980-nm diode laser ablation system in a large animal tumor model.

PURPOSE: To characterize the performance of a 980-nm diode laser ablation system in an in vivo tumor model. MATERIALS AND METHODS: This study was approved by the institutional animal care and use committee. The ablation system consisted of a 15-W, 980-nm diode laser, flexible diffusing-tipped fiber optic, and 17-gauge internally cooled catheter. Ten immunosuppressed dogs were inoculated subcutaneously with canine-transmissible venereal tumor fragments in eight dorsal locations. Laser ablations were performed at 79 sites where inoculations were successful (99%) at powers of 10 W, 12.5 W, and 15 W, with exposure times between 60 and 180 seconds. In 20 cases, multiple overlapping ablations were performed. After the dogs were euthanized, the tumors were harvested, sectioned along the applicator tract, measured, and photographed. Measurements of ablation zone were performed on gross specimen. Histopathology and viability staining was performed with hematoxylin and eosin and nicotinamide adenine dinucleotide hydrogen staining. RESULTS: Gross pathologic examination confirmed a well circumscribed ablation zone with sharp boundaries between thermally ablated tumor in the center surrounded by viable tumor tissue. When a single applicator was used, the greatest ablation diameters ranged from 12 mm at the lowest dose (10 W, 60 seconds) to 26 mm at the highest dose (15 W, 180 seconds). Multiple applicators created ablation zones as large as 42 mm in greatest diameter (with the lasers operating at 15 W for 120 seconds). CONCLUSIONS: The new 980-nm diode laser and internally cooled applicator effectively create large ellipsoid thermal ablations in less than 3 minutes.

Hepatic artery chemoembolization in patients with ocular melanoma metastatic to the liver: response, survival, and prognostic factors.

BACKGROUND: Although hepatic arterial chemoembolization (HACE) has been used for treatment of ocular melanoma metastatic to the liver, the prognostic indicators for survival after HACE have not been studied. We evaluated response rates and survival durations after HACE in such patients and analyzed factors affecting their survival. METHODS: The medical records of patients with ocular melanoma metastatic to liver who underwent HACE at our institution from 1992 to 2005 were reviewed. The radiologic tumor response rates, and overall survival (OS) and progression-free survival durations were calculated, and patient, tumor, and treatment variables were analyzed to identify factors influencing survival. RESULTS: One hundred twenty-five patients underwent 265 HACE sessions. Of 105 patients in whom radiologic responses could be evaluated, 12 (11%) had partial responses, 17 (16%) had minor responses, 68 (65%) had stable disease, and 8 (8%) had progressive disease. The median OS and progression-free survival durations were 6.7 and 3.8 months, respectively. Multivariate analysis showed that >75% liver involvement and high lactate dehydrogenase levels were associated with short OS. Patients who had radiologic responses to HACE had a longer median OS duration than did patients who did not (15.8 vs. 6.1 months; P = 0.0005). Patients with >75% liver involvement had a median OS duration of only 2.4 months. CONCLUSIONS: HACE resulted in radiologic response or disease stabilization in most patients with ocular melanomas metastatic to the liver. The extent of liver involvement, baseline lactate dehydrogenase levels, and response to therapy were found to be significant predictors of OS after HACE.