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ABSTRACT |
Thursday, May 10, 1:30 PM–3:30 PM
Abstracts 250-260
Moderator(s): Brian Funaki and Aravind Arepally
1:30 AM
Keynote Address: New Interventional Procedures Under MR Guidance: New Concepts
Aravind Arepally, Johns Hopkins Medical Institutes, Baltimore, MD
1:40 PM
250. Peripheral Angiography with 16-row MDCT: Optimization of Acquisition Speed—A Quantitative Comparative Study of Arterial Enhancement
Meyer B.*; Albrecht T. Charite, Campus Benjamin Franklin, Berlin, Germany
Address correspondence to B. Meyer (bernhard.meyer{at}charite.de)
Objective: To compare the degree of intraarterial enhancement along the peripheral vascular tree for 16-slice MDCT peripheral angiography at three different table feeds.
Materials and Methods: 147 patients with peripheral arterial
disease underwent CTA of peripheral arteries using a Somatom Sensation 16
(Siemens, Germany) with 16 x 1.5 mm collimation, 0.5 s rotation time, 2
mm slice thickness, 1.2 mm reconstruction interval. Table feed was varied [30
mm/s; n = 29(A); 40 mm/s, n = 87(B) or 48 mm/s, n =
31(C)]. Twelve patients showed an additional aneurysm of the aorta abdominalis
or the pelvic arteries [n = 3(A), 4(B) and 5(C)]. 100 ml Iomeprol 400
(Bracco, Italy) was injected at 4 ml/s followed by 50 ml of saline solution.
Bolus tracking was performed in the aorta. Scans were started 4 s after a
threshold of 250
HU was reached. Arterial enhancement was measured in
intervals of 10 cm from the start point in the suprarenal aorta to the distal
calf arteries.
Results: The mean arterial enhancement shows a slight increase,
reaches a maximum at 30 cm (A: 377 ± 93HU) 60 cm (B: 370
± 147HU) and 70 cm (C: 399 ± 99HU) and decreases
slowly down to the distal calf and feet. The enhancement in the calf arteries
is significantly higher when table feed is increased in the patients without
aneurysms (n = 135; A: 162 ± 66HU, B: 210 ±
90HU, C: 256 ± 86HU, p < 0.05). In patients
with aortic aneurysms the maximum contrast enhancement decreases with
increased table feed. In this group, the lowest enhancement was achieved with
the highest table feed used.
Conclusion: The best intraarterial contrast enhancement profile along the z-axis was achieved when the highest table feed (48 mm/s) was used. In this group the mean arterial enhancement in the calf was significantly higher as compared to lower table feed settings using an unchanged contrast media injection protocol. In patients with aortic or pelvic aneurysms, table feed should be reduced.
251. Feeding Arteries of the Spine at CT Angiography Before and After Thoracic Aortic Endografting
von Tengg-Kobligk H.1*; Jose T.1; Ganten M.1; Kotelis D.2; Boeckler D.2; Kauczor H.1 1. German Cancer Research Center (dkfz), Heidelberg, Germany; 2. University of Heidelberg, Heidelberg, Germany
Address correspondence to H. von Tengg-Kobligk (h.vonTengg{at}dkfz.de)
Objective: To study the visualization of spinal arteries by multislice CT angiography (MSCTA) in patients with complex thoracic aortic pathology undergoing endovascular aortic repair (EVAR).
Materials and Methods: Eighteen consecutive patients (5 F, 13 M, mean age 60 years) with thoracic aortic Type B dissection (n = 5), chronic aortic expanding dissection (CEAD, n = 5), thoracic aortic aneurysm (TAA, n = 6) or penetrating aortic ulcera (PAU, n = 2) underwent 16-slice CTA (120 kV, 120-150mAs, 1 mm collimation; multiplanar reformations and MIP reconstructions were obtained using 1 mm source data) before and after EVAR (mean interval: 9 days). Neurological status was documented. Contrast medium (Iomeprol 400; 400 mgI/ml) was administered at 5 ml/s. Quantitative density measurements were taken at ROIs in the ascending thoracic aorta and at the level of the diaphragm. Qualitative analysis by two experienced radiologists comprised assessment of the posterior intercostal arteries (PIA; existent, 50%, nonexistent), dorsal branches (DB; existent/nonexistent) and Adamkiewicz artery (AKA; existent/nonexistent).
Results: Pre-EVAR MSCTA was performed successfully in all, postEVAR in 17/18 patients. Pre-EVAR MSCTA revealed 197/203 PIA within the to-be-stented area of which 179 were fully and 18 partially (50%) visible. No significant (p = 0.99) difference was noted for overall PIA detection within the stented area on postEVAR MSCTA (185/203 PIA) however only 124 were fully and 61 partially visible. Similar results were obtained for DB visualization. AKA were seen in 10/17 patients pre-EVAR and 9/17 postEVAR. Partially thrombosed aortic lumen limited AKA visualization in some patients. In two patients the AKA was localized within the stented aortic segment and was visualized before and after EVAR. ROI analysis revealed mean contrast densities of 428 ± 89 HU pre-EVAR and 398 ± 84 HU postEVAR. No neurological events were observed.
Conclusion: High-contrast MSCTA permits visualization of spinal cord feeding arteries. Pre-operative planning might benefit from noninvasive MSCTA. EVAR did not significantly impair blood supply to the spinal cord.
252. Improving Image Quality of the Sonic Flashlight for Venous Access
Wang D. C.3*; Amesur N. B.1; Weiser D.2; Chang W.2; Zajko A. B.1; Stetten G. D.2 1. University of Pittsburgh Medical Center, Pittsburgh, PA; 2. University of Pittsburgh, Department of Bioengineering, Pittsburgh, PA; 3. University of Pittsburgh, School of Medicine, Pittsburgh, PA
Address correspondence to D. Wang (david{at}wangmd.com)
Objective: The sonic flashlight (SF) is an ultrasound (US) device that replaces the conventional ultrasound (CUS) monitor with a small display and a semi-reflective/transparent mirror to reflect real-time US images into the body. Looking through the mirror, the virtual US image appears to float beneath the skin, exactly where the scan is being obtained. The SF merges the US image, probe, needle, operator's hands, and patient into the same field of view, making procedures more intuitive. In contrast, CUS displaces hand-eye coordination by forcing the operator to look away from the operating field to see the US display. We have previously used the SF to successfully place PICC lines in 15 patients. However, because the sterile procedure required a cover for the US probe, the visibility was significantly degraded. We have since redesigned the SF to solve this problem, and the purpose of this study is to demonstrate the functionality of our solution.
Materials and Methods: The redesigned SF consists of a 10-MHz US system (Terason, Burlington, MA) whose probe is fitted with a small flat-panel display (AM550L OLED, Kodak, Rochester, NY), but without a dedicated mirror. A standard sterile clear probe cover (BARD, Murray Hill, NJ) is fitted over the probe and the display. A disposable sterile mirror holder with a 20 x 50 x 2 mm semi-reflective/transparent plastic mirror is then fitted outside the cover, pressing the cover flat against the display. Eleven patients needing PICCs were enrolled in this study. While scanning their upper arms, the basilic and brachial veins, and brachial artery were identified in the virtual US image. A 21-gauge needle was guided into the basilic or brachial vein. We recorded the number of punctures and vein accessed.
Results: The vessels were clearly visualized in situ for all patients using the SF. The needle was easily aimed and inserted into the target vein, and the needle tip visualized at its expected location. Successful access was obtained in all 11 subjects: 8 on first puncture, 2 on second, and 1 on third; 8 in the basilic vein and 3 in the brachial vein. Image degradation due to the bag was no longer appreciable.
Conclusion: This study shows that venous access can be safely obtained using the SF, and we believe our new disposable mirror outside the bag satisfies the requirement for sterility without significantly degrading visibility. Clinical trials to use this system for other central veins, as well as for PICC line placement by nurses at the bedside are now underway.
253. Contrast-enhanced MR Angiography for Detection of Pulmonary Arterio-venous Malformations in Patients with Hereditary Hemorrhagic Telangiectasia (HHT)
Schneider G. K.2*; Massmann A.2; Fries P.2; Geisthoff U.4; Koehler M.3; Uder M.1; Buecker A.2 1. University Hospital, Department of Radiology, Erlangen, Germany; 2. Saarland University Hospital, Department of Diagnostic and Interventional Radiology, Homburg, Germany; 3. University Hospital, Department of Radiology, Muenster, Germany; 4. Saarland University Hospital, Department of Otorhinolaryngology, Homburg, Germany
Address correspondence to G. Schneider (ragsne{at}uniklinik-saarland.de)
Objective: To evaluate contrast-enhanced MR angiography (CE-MRA) as a screening procedure for detection of pulmonary AV-malformations (PAVM) in patients with hereditary hemorrhagic telangiectasia (HTT).
Materials and Methods: 203 consecutive patients (87 men, mean age 47.4 ± 17.6 years; 116 women, 46.1 ± 15 years) with confirmed HHT according to Curaçao criteria underwent screening pulmonary CE-MRA with gadobenate dimeglumine (0.1 mmol/kg bodyweight) for the presence of PAVMs. PAVM presence was scored as 0 (= none present), 1 (= definitely present) or 2 (= uncertain) and was evaluated by patient gender, age (<25, 25-65, >65 years) and PAVM size (< 5, 5-10, 11-15, 16-20,>20 mm). Patients scored as 1 or 2 with at least one PAVM of = 5 mm were referred for conventional pulmonary angiography (PA) for possible embolization.
Results: Overall, 56/203 (27.6%) patients were scored as 1 (definite) and 1/203 (0.5%) as 2 (uncertain) for pAVM presence on CE-MRA. Overall, CE-MRA detected 156 PAVMs in these 57 patients (65 in 27 men; 91 in 30 women of which 82 were in 25 women of 26-65 years). Two or three PAVMs were detected in 21 patients and four or more in 11 patients. Most PAVMs detected on CE-MRA were small (<5 mm: n = 49; 5-10 mm, n = 61). 40 of 57 patients with 119 evaluable PAVMs detected on CE-MRA underwent global or selective PA. Significantly (p < 0.001) fewer pAVMs (92/119 [77.3 %]) were demonstrated on PA of which 82 were embolized.
Conclusion: CE-MRA is a suitable screening procedure for patients with HHT, permitting accurate detection and staging of PAVMs and appropriate differentiation of lesions requiring embolization.
254. Triple Agent Sedation: Midazolam, Fentanyl, and Ketamine in Combination for Pediatric Interventional Procedural Sedation
Temple M.*; Murray D.; Kemp S. Hospital for Sick Children, Toronto, Canada
Address correspondence to M. Temple (michael.temple{at}sickkids.ca)
Objective: The goal of this study is to assess the safety and efficacy of nurse-administered, radiologist-supervised midazolam, fentanyl, and ketamine sedation used during interventional procedures in children.
Materials and Methods: All patients who underwent procedures and received intravenous midazolam, fentanyl, and ketamine bolus sedation are reviewed. Data collected from sedation records, quality assurance forms, patient chart, and the ESH-IGT Database. Demographics, vitals, doses, adverse events, postprocedure patient follow-up, and procedural performance data (fluoroscopy time, room time, ability to perform procedure, procedural complications) were recorded.
Results: From May 2005-Sept. 2006, 316 patients underwent interventional procedures under sedation. Thirty-four patients who received 3 sedation agents are included in the study. Procedures performed were biopsy (n = 13), central venous access (7), abscess drainage (4), steroid injection (9) and cecostomy tube insertion (1). Age ranged from 14 months to 16 years (avg. 7.4 ± 4.3 years) and weight from 11 to 90 kg (avg. 29.3 ± 18.9 kg). Patients are ASA 1 (n = 13); ASA 2 (15) and ASA 3 (6). Total drug doses were midazolam 0.07 ± 0.03 mg/kg, range 1-3 doses; fentanyl 1.7 ± 0.6 µg/kg, range 1-5 doses; and ketamine 0.4 ± 0.2 mg/kg, range 1-3 doses. Transient hypoxia treated with nasal O2 in 1 patient (3%). Emergence reaction controlled with midazolam in 2 patients (6%). All procedures performed successfully within 75 minutes (avg. 41 ± 14 mins). There were no procedural complications. All sedations were successful. All patients that were questioned after recovery were either satisfied with sedation or amnestic of event. 22/23 patients (96%) questioned did not remember any pain or the procedure itself. 1/23 patients (4%) remembered discomfort/pain but would undergo sedation again.
Conclusion: All sedations successful. No significant adverse events. Synergistic effect of sedation agents allows potentially lower doses of ketamine usage with low incidence of emergence reaction seen. Titration of 3 agents allows: 1) individualized sedation optimization, 2) avoidance of general anesthesia in younger patients, and 3) wider range of procedures can be performed under sedation.
255. Multi-bolus Contrast Injection Protocol for Multidetector Row CT Angiography of Renal Donors: Evaluation with Surgical Correlation (Work-in-progress)
Namasivayam S.2*; Kalra M. K.2; Mittal P. K.1; Sahani D. V.2; Small W. C.1 1. Emory University Hospital, Atlanta, GA; 2. Massachusetts General Hospital, Boston, MA
Address correspondence to S. Namasivayam (namasivayam2005{at}yahoo.com)
Objective: MDCT angiography of renal donors comprises dedicated arterial and venous phases. We hypothesize that a multi-bolus contrast injection protocol would enable single phase MDCT angiography for evaluation of renal arterial, and major and minor venous anatomy. The purpose of our study was to evaluate multi-bolus contrast protocol for MDCT angiography of renal donors with surgical correlation.
Materials and Methods: The institutional review board approved our study. Thirty-two renal donors (M:F, 15:17; mean age, 36 years) underwent MDCT (64-slice) angiography. After acquisition of unenhanced images, contrast material (130 mL of 350 mgI/mL Iohexol) was injected by multi-bolus protocol (40 mL at 3 mL/s, 10 mL at 0.4 mL/s, and 80 mL at 4 mL/s). Postcontrast images were acquired after a 70-second delay from start of contrast injection. A scout image was obtained after 5 minutes. Two radiologists evaluated postcontrast images for renal arterial and venous anatomy, calculi, and diagnostic acceptability of vascular enhancement (five-point scale). Unenhanced images were reviewed for calculi, and delayed scout was evaluated for urinary tract anomalies. Electronic medical records were reviewed for operative findings.
Results: To date 12 patients have gone to laparoscopic left nephrectomy. Hence, CT findings for left renal vascular anatomy were correlated with surgical findings for these patients. CT revealed two left renal arteries (n = 5), retroaortic left renal vein (n = 1), circumaortic left renal vein (n = 1), and bifid left gonadal vein (n = 1). These findings were concordant with surgical findings except for circumaortic left renal vein which was labeled as large lumbar vein by surgeon. Sensitivity, specificity, and accuracy of CT for detection of renal arterial and major venous anatomy were 100%, 100% and 100%, and 100%, 91% and 92%, respectively. Left adrenal and gonadal veins were detected in all the patients on CT which were confirmed at surgery. Likewise, left lumbar vein was identified in 9 patients on CT, which were confirmed at surgery. None of these 12 patients had calculi or urinary tract anomalies. Overall renal vascular enhancement was diagnostically acceptable in all patients.
Conclusion: Multi-bolus contrast injection protocol offers a single phase MDCT angiography technique for renal donors, which can accurately determine the renal arterial, and major and minor renal venous anatomy. Multi-bolus contrast protocol negates the need for venous phase CT acquisition and thus, may help reduce radiation dose.
256. Volumetric Fluoroscopic Soft Tissue Imaging (Fluoro CT): Initial Interventional Radiology Experience
Pena C. S.*; Katzen B. T.; Benenati J. F.; Zemel G.; Powell A.; Samuels S. Baptist Cardiac & Vascular Institute, Miami, FL
Address correspondence to C. Pena (tinopena{at}msn.com)
Objective: The purpose of this study is to demonstrate the initial clinical experience and potential utility of three dimensional soft tissue imaging acquired on a commercial flat panel C-arm in an interventional suite.
Materials and Methods: Pre-clinical release of a three-dimensional acquisition system was utilized. This software allowed a commercial C-arm equipped with a large field of view flat panel detector (40 cm by 30 cm) to acquire 621 projections at 30 frames per second during a 205 degree rotation of the C-arm. Cone beam volumetric reconstruction was then performed resulting in a 25 x 25 x 19 cm3 volume. This volume when reconstructed to 256 x 256 x 198 voxels features an isotropic resolution of 0.98 x 0.98 x 0.98 mm3. This CT-like imaging volume technique was used in various vascular and nonvascular interventional procedures to assess its feasibility and utility.
Results: A total of 35 patient examinations were conducted. A diverse group of clinical applications in both vascular and nonvascular scenarios were explored. The imaging technique was utilized to evaluate arterial vessel characteristics such as thrombus, calcification, and size. Volumetric soft tissue imaging facilitated renal and biliary drainage procedures as well as improved evaluation during and after vertebroplasty, gastrostomy tube placements, direct aneurysm sac punctures and biopsies. The role for the immediate evaluation of patients for acute retroperitoneal or intracerebral hemorrhage was also identified. In 80% of patients, additional clinical information was obtained directly affecting interventional therapy.
Conclusion: Soft tissue cross-sectional imaging acquired from a flat panel C-arm fluoroscopic unit is feasible and has utility in interventional radiology procedures. Its integration with conventional interventional fluoroscopic imaging proves to have great potential for interventional procedures.
257. Multislice CT Angiography (MSCTA) of the Spinal Vasculature Before and After Endovascular Aortic Repair in an Animal Model: A Comparison of Two Contrast Agents
von Tengg-Kobligk H.1*; Jose T.1; Kotelis D.2; Ganten M.1; Giesel F. L.1; Boeckler D.2; Kauczor H.1 1. German Cancer Research Center (dkfz), Heidelberg, Germany; 2. University of Heidelberg, Heidelberg, Germany
Address correspondence to H. von Tengg-Kobligk (h.vonTengg{at}dkfz.de)
Objective: To study the visualization of the intercostal arteries before and after proximal occlusion. To compare if higher iodinated contrast media improve vascular visualization in multislice CT angiography (MSCTA).
Materials and Methods: MSCTA of the thoracic aorta was performed in ten healthy sheep. Five animals received endovascular aortic repair (EVAR) of the entire thoracic aorta using a commercial endograft while the other five received proximal clipping of the posterior intercostal arteries (PIA). Pre-EVAR, postEVAR and follow-up MSCTA were performed using a 16-slice CT scanner (120 kV, 150 mAs and 1 mm collimation). Two contrast agents with different iodine concentrations (Iomeprol; 300 and 400 mg I/ml; 5 ml/s) were compared between postEVAR and follow-up MSCTA. Pulse rate was monitored by ECG. Qualitative analysis of the PIAs (fully visualized, 50% full length, not visualized) and the dorsal branches (fully visualized, not visualized) was performed by two experienced radiologists. Overall, 260 PIAs and 260 dorsal branches (n = 194 in the non-stented area, n = 66 in the stented area) were assessed before and after EVAR. Quantitative density [HU] measurements were made at ROIs in the ascending aorta and at the level of the diaphragm.
Results: 19/20 CTA exams were performed successfully. The mean density in the thoracic aorta was 454 ± 57 HU (median = 453 HU) with Iomeprol 400 and 338 ± 25 HU (median = 331 HU) with Iomeprol 300 (p < 0.005). Mean heart rate was 68 bpm in the first exam and 67 bpm in the second. Qualitative analysis revealed sufficient contrast to allow delineation of the spinal vessels in all exams. PostEVAR within the stented area only one PIA (1.5%) and one dorsal branch (1.5%) were occluded; n = 49 (74.3%) PIAs were visualized to 50% full length, while n = 16 (24.2%) PIAs were fully visualized. Thus retrograde perfusion occurred in 98.5% of PIAs postEVAR allowing perfusion of the dorsal branches.
Conclusion: Visualization of the spinal cord feeding arteries is possible on MSCTA. The majority of posterior intercostal arteries demonstrate retrograde perfusion postEVAR. Better visualization of the spinal cord feeding arteries is achieved using high iodine concentration contrast media.
258. Diagnostic Accuracy of Contrast-enhanced MR Angiography with Gadobenate Dimeglumine
Schneider G.4; Ballarati C.6; Grazioli L.5; Manfredi R.3; Thurnher S.2; Kirchin M. A.1 1. Bracco Imaging SpA, Milano, Italy; 2. Department of Radiology and Nuclear Medicine, Vienna, Austria; 3. Ospedale Borgo Roma, Verona, Italy; 4. University Hospital Saarland, Homburg, Germany; 5. University of Brescia, Brescia, Italy; 6. Valduce Hospital, Como, Italy
Address correspondence to G. Schneider (ragsne{at}uniklinik-saarland.de)
Objective: To determine the accuracy of contrast-enhanced MR angiography (CE-MRA) with four doses of gadobenate dimeglumine (Gd-BOPTA) for detection of significant steno-occlusive disease versus DSA.
Materials and Methods: Eighty-four patients with suspected disease of the renal (n = 16), pelvic (n = 41) or carotid (n = 27) arteries underwent CE-MRA (3D-spoiled gradient-echo sequences at 1.5 T) and DSA. CE-MRA was performed with Gd-BOPTA at 0.025, 0.05, 0.1 or 0.2 mmol/kg (21, 25, 17 and 21 patients, respectively). Sensitivity, specificity, and accuracy versus DSA for detection of significant disease (>50% stenosis/occlusion for renal/pelvic arteries; >70% stenosis/occlusion for carotid arteries) was determined by three fully blinded, independent radiologists. All comparisons were tested statistically (McNemar and Chi-square tests) and reader agreement (kappa) was assessed.
Results: Sensitivity values of 44.4–70.4%, 55.9–67.6%, 84.2% (all readers) and 65.2–69.6% were determined for Gd-BOPTA doses of 0.025, 0.05, 0.1 and 0.2 mmol/kg bodyweight, respectively. Specificity (78.2–90.3%, 83.3–91.3%, 96.9–99.2% and 83.8–86.5%, respectively) and accuracy (75.5–82.1%, 80.4–87.0%, 95.2–97.3% and 81.3–82.8%, respectively) values similarly favored a Gd-BOPTA dose of 0.1 mmol/kg bodyweight. The greater accuracy of the 0.1 mmol/kg dose was significant (p < 0.01, all readers) compared to all other dose groups. Agreement between the three readers was good to excellent for all dose groups (kappa = 0.60)
Conclusion: Significantly better diagnostic performance on CE-MRA of the renal, pelvic and carotid arteries is achieved with a Gd-BOPTA dose of 0.1 mmol/kg bodyweight.
259. CT-Guided Therapy of Refractory Pudendal Neuralgia: Indications, Techniques, and Preliminary Results
Dehkharghani S.*; vanSonnenberg E.; Moore M. T.; Hedayati P.; Oyola E.; Hibner M. St. Joseph's Hospital and Medical Center, Phoenix, AZ
Address correspondence to S. Dehkharghani (seena.dehkharghani{at}chw.edu)
Objective: Chronic pelvic pain is a source of chronic disability in both sexes. The emergence of a controversial entity known as pudendal neuralgia has expanded the diagnostic gamut of chronic pelvic pain. Recent investigations have elucidated the pathophysiology of pudendal nerve entrapment and described the mechanisms of nerve compromise. The absence of a confirmatory test has perpetuated the enigmatic nature of the disorder, often leading to technically challenging exploratory surgery for suspected nerve entrapment. CT-guided pudendal nerve blockade has been proposed as a minimally invasive technique with both diagnostic and therapeutic efficacy. We sought to assess the utility of CT-guided pudendal nerve blockade in a series of patients with suspected pudendal neuralgia, with special attention to the anatomic issues of nerve entrapment, and the technical aspects of the procedure.
Materials and Methods: Nineteen patients (17 women, 2 men) referred by a gynecologist specializing in pelvic pain underwent a total of 27 pudendal nerve blocks for suspected pudendal neuralgia. Alcock's canal (obturator internus aponeurosis), the expected location of the pudendal nerve, was identified by thin section CT, and accessed with 22-gauge biopsy needles. The anatomic margins of the canal were confirmed by the injection of 3-5 cc of nonionic contrast, and followed by a therapeutic injectant consisting of a short-acting anesthetic and intermediate acting corticosteroid. Pre- and post-procedure visual analogue scale assessment was performed, with a decrease of greater than two defined as significant, and suggestive of pudendal neuralgia.
Results: Alcock's canal was identified and accessed successfully in all patients, and percutaneously distended with contrast. Immediate amelioration of symptoms was achieved in 22 of 27 (81.5%) nerve blocks, and 15 of 19 (74.9%) total patients (VAS >2 decrease), effectively establishing the diagnosis of pudendal neuralgia. One patient (3.7%) reported permanent resolution of symptoms after a single nerve block. No complications occurred.
Conclusion: CT-guided pudendal nerve blocks provide diagnostic information in enigmatic cases of chronic pelvic pain and suspected pudendal neuralgia. The therapeutic efficacy of pudendal nerve blockade may provide temporizing beneficial effect or cure, and serve as an alternative to surgical nerve release. While early, results are promising and deserve further investigation.
260. Sonographic Shadowing from Viatorr TIPS Prosthesis: When Does it Disappear and Permit Assessment of Shunt Patency?
Sharp M. J.*; Smith J. C.; Broome D. R. Loma Linda University Medical Center, Loma Linda, CA
Address correspondence to M. Sharp (msharp{at}ahs.llumc.edu)
Objective: Viatorr-covered stents placed for transjugular intrahepatic portosystemic shunts (TIPS) cause acoustic shadowing which prevents Doppler assessment of shunt patency in the early post procedural period. The purpose of this study was to determine the optimal time for initial Doppler surveillance of Viatorr-covered stents for shunt patency.
Materials and Methods: Between October 2003 and September 2006, 52 consecutive patients underwent TIPS (n = 49) or direct intrahepatic portocaval shunt (DIPS) (n = 3) placement with a Viatorr-covered stent. 43 of these 52 patients had ultrasound (US) with color and spectral Doppler evaluation of the shunts performed at variable time periods, from 1 day to greater than 1 week post TIPS/DIPS. Nine patients were excluded from the study because of lack of adequate follow-up, patient demise, or alternative imaging was pursued. When acoustic shadowing from the covered stents did not allow detection of Doppler flow and when clinical situations warranted, further investigation of stent patency was performed with follow-up Doppler and/or imaging with CT, MRA or conventional portovenography. Using stent patency as the true positive and thrombosis as the true negative, the sensitivity and negative predictive value of Doppler for detection of stent patency were calculated at various time points after stent insertion.
Results: Forty-three patients had 55 ultrasound exams and confirmation of patency status either on initial US or other follow-up imaging. Doppler imaging was performed post stent deployment within 24 hours (n = 2), 24-48 hours (n = 23), 48-72 hours (n = 10), 72 hours-1 week (n = 4), and greater than 1 week (n = 16). Confirmatory CT, MRA or conventional portovenography follow-up was obtained in 14 patients. Sensitivities for flow within the stent graft at < 48 hours, 48-72 hours, and >72 hours were 62%, 70%, and 100%, respectively. Negative predictive values at < 48 hours, <72 hours, and >72 hours were 10%, 8%, and 100%.
Conclusion: Due to acoustic shadowing from entrapped air bubbles in the Viatorr-covered stent, shadowing may render Doppler US nondiagnostic up to 1-week post-deployment. Waiting greater than 72 hours post-deployment for initial US interrogation offers the highest sensitivity and negative predictive value for determining shunt patency.
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