Imaging: Vascular anatomy and pathology

Imaging: Vascular anatomy and pathology

with 95% confidence intervals in parentheses for the imaging modalities respectively were: MRV: 98.7 (95.3-99.8)/ 95.4 (92.5-97.4)/Az ⫽ 0.970 (0.951-0...

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with 95% confidence intervals in parentheses for the imaging modalities respectively were: MRV: 98.7 (95.3-99.8)/ 95.4 (92.5-97.4)/Az ⫽ 0.970 (0.951-0.984); Ultrasound: 90.8 (88.3-92.9)/96.5 (95.3-98.5)/Az ⫽ 0.937 (0.9250.947). Chi-square with Yates correction showed that MRV had significantly higher sensitivity (P ⬍ 0.001) than ultrasound, with no significant difference in specificity. CONCLUSION: MRV demonstrates significantly higher sensitivity than duplex ultrasound in the detection of lower extremity DVT, without a significant difference in specificity. While ultrasound should remain as the first-line test for DVT secondary to its cost and excellent operating characteristics, MRV should be considered an option in technically inadequate or non-diagnostic sonographic studies. Abstract No. 253 Ultrasound-guided Deep Extraction of the Impalpable Implanon. J.S. Fasulakis, Royal Women’s Hospital, Melbourne, Australia 䡠 C. Garlick 䡠 D. Palmer PURPOSE: Implanon® is a contraceptive implant containing progestogen. Removal of these devices is usually uncomplicated and performed without image guidance by a general practitioner. However, removal of the impalpable implant may be challenging and we present a technique which has proven to be very useful in management of these difficult cases. MATERIALS AND METHODS: Patients were referred to us from general practice and from our hospital well women’s clinic. The device is located using ultrasound and under sterile conditions, the skin is infiltrated with local anesthetic. In some cases a Chiba needle is positioned behind the device in order to stabilize it. A small incision is then made and, under ultrasound guidance, the device is grabbed with a hemostat and removed. RESULTS: 42 removals have been performed in an 18month period. All 42 cases were successful on the first attempt. A review of the most recent 26 removals indicated that 11 patients (42%) had undergone previous unsuccessful attempts at removal. Of these, 2 (18%) had three prior attempts, 1 patient (9%) had two failed attempts and 8 patients (73%) had one failed attempt. Of these 11 patients who had previous attempts at removal, 2 (22%) had incorrect localization of the implant. The average time taken to remove the implant ranged from 10.4 minutes in the group who had no previous attempts at removal, to 12 minutes in that group who had previous unsuccessful attempts at removal. Although complications such as nerve injuries and infection have been described, no such complications were encountered by us. CONCLUSION: We describe an effective and safe technique for removing the impalpable Implanon® contraceptive implant.

Imaging: Vascular Anatomy and Pathology Abstract No. 254 Origin of the Right Inferior Phrenic Artery: Investigation Using DSA and Thin-Section Spiral CT in 591 Patients. Y.H. So, Seoul National University Hospital, Seoul, JongnoGu, Korea 䡠 J.W. Chung 䡠 H.J. Jae 䡠 H.-C. Kim 䡠 W. Lee 䡠 J.H. Park PURPOSE: To investigate origin sites of the right inferior phrenic artery (RIPA) using DSA and thin-section spiral CT. MATERIALS AND METHODS: We analyzed origin sites of the RIPA with DSA and thin-section spiral CT in 591 patients who underwent TACE from July 1998 to June 2006. Slice thickness and interval for spiral CT were 2.5-3.2 mm and 2.5-3 mm, respectively. RIPA arteriography was performed to evaluate collateral supply for hepatic tumors. RESULTS: The RIPA was occluded and supplied by collateral arteries in six patients. In four patients, the origin of the RIPA was not identified on CT. So, we can analyze origin sites of the RIPA on thin-section CT in 581 patients. Among them, 514 patients had normal celiac anatomy and the remaining 67 patients had celiac trunk variation. In 514 patients with normal celiac trunk, the RIPA arose from aortic branches in 237 patients (46%; celiac trunk in 160, right renal artery in 77, left renal artery in 2, right internal mammary artery (RIMA) in 1) and directly from the aorta in 277 patients (54%; supraceliac in 90, juxtaceliac in 57, between celiac trunk and SMA in 65, SMA level in 37, suprarenal 28). In 277 patients with aortic origin of the RIPA, it arose from the left side of the celiac trunk (from supraceliac to left suprarenal) in 43 patients (16%). In 67 patients with celiac trunk variation, 31 patients had separate origin of the left gastric artery (LGA) and gastrosplenic trunk. In 31 patients, the RIPA most commonly arose from the supraceliac aorta as a common trunk with the LGA in 12 patients (39%). Unusual origin of the RIPA from the SMA was found in one patient. In the other types of celiac trunk variation, distribution of origin sites of RIPA was similar to that in patients with normal celiac trunk. The unusual origin sites of the RIPA were high supraceliac aorta, RIMA, proximal SMA, left renal artery, and posterior aspect of the aorta. Supradiaphragmatic origin and transdiaphragmatic course of the RIPA was found in three patients. CONCLUSION: By combined analysis of DSA and thinsection CT, it was possible to analyze origin sites and anatomical course of the RIPA. Typically, the RIPA arises from aorta or its branches along the line from the supraceliac aorta to the right renal artery including celiac trunk. However, it can arise from unusual locations. Abstract No. 255 MDCT Evaluation of Incidental Celiac Axis Stenosis: Incidence, Causes, and Anatomic Characteristics. S.-Y. Song, Hanyang University Hospital, Seoul, Republic of Korea 䡠 J. Kim 䡠 O.K. Cho 䡠 B.H. Koh 䡠 Y. Kim PURPOSE: To evaluate the incidence, causes, and anatomic characteristics of incidentally detected celiac axis stenosis (CAS) on MDCT.

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MATERIALS AND METHODS: We prospectively evaluated MDCT data set for abdominal examination in 500 patients. We evaluated the incidence and causes of CAS, compromising more than 50% of the luminal diameter. CAS resulting from extrinsic compression by the median arcuate ligament (MAL) was defined as celiac axis compression syndrome (CACS), while that resulting from atheroma was defined as atherosclerosis. We classified patients into three groups according to the degree of overlap of MAL on the celiac axis orifice (group A, overlapping of 1-50%; group B, 50-99%; group C, more than 100%) and also evaluated the incidence of CACS in each group.

anteromedial aspect. The majority of the subjects fell on 41 and 45 degrees and 46 to 50 anteromedial degrees group (both groups were at 19.8%). The left renal arterial pedicle angle ranged between 10 and 100 degrees anteromedial and the majority of the subjects fell on the 51 to 55 degree anteromedial group (13.8%).

RESULTS: One hundred three patients (20.6%) had CAS. The causes were CACS in 53.4% (55/103) of patients, atherosclerosis in 33% (34/102), both CACS and atherosclerosis in 5.8% (6/103), and undetermined in 7.8% (8/ 103). The age and sex of patients with CACS did not significantly differ from the general population. The incidence of atherosclerosis was significantly higher in the elderly, accounting for 56.1% (32/57) of CAS in patients older than 60 years. The incidence of CACS was 0% (0/151) in group A, 25.8% (16/62) in group B, and 55.9% (38/68) in group C.

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CONCLUSION: Incidental CAS was a frequent condition. Overall, the most important cause was CACS. Atherosclerosis was also an important cause, particularly in the elderly. More than 50% of overlap of MAL on the celiac axis orifice was needed to develop CACS. Abstract No. 256 Renal Artery Anatomy: Distribution of the Renal Artery in the Aorta and Angle of the Renal Pedicle. U.C. Turba, Medical University of South Carolina, Charleston, SC, USA 䡠 R. Uflacker 䡠 J.B. Selby 䡠 C. Schonholz 䡠 C. Hannegan PURPOSE: Present the results of an anatomic review, regarding angles, sizes and location of the renal arteries in relationship with the aorta and renal hilum in a normal adult population, using the capabilities of CT angiography.

RESULTS: A total of 399 patients and aortas, and 798 renal arteries were evaluated using MDCT. The right renal ostium angle ranged between 0 and 70 degrees in the anterolateral aspect. In the majority of the subjects the ostium position fell 31-35 degrees in anterolateral group (16.6%). The left renal ostium angle ranged between 35 degrees anterolateral and 50 degrees posterolateral aspects. In the majority of the subjects the ostium position fell between 11 and 15 degrees in the left posterolateral group (18.8%). Renal arterial pedicle (renal hilum) findings: Using 5 degree clusters; the following results were obtained; The right renal arterial pedicle angle ranged between 70 and 0 degrees in the

Current Histologic and Radiologic Classification of Vascular Anomalies and Implications for Percutaneous Therapy. A. Mahajan, Vancouver Gen. Hospital, Univ. of British Columbia, Vancouver, BC, Canada 䡠 G.M. Legiehn PURPOSE: Past terminology and lack of experience still leads to misdiagnosis and inappropriate treatment of vascular anomalies. The International Society for the Study of Vascular Anomalies (ISSVA) currently divides this group into vascular tumors, most commonly infantile hemangiomas, and vascular malformations which are comprised of capillary malformations (CM), venous malformations (VM), lymphatic malformations (LM) and arteriovenous malformations (AVM). Clinical, histologic, and radiologic findings of these entities and further subclassification schema are presented to optimally direct therapy. MATERIALS AND METHODS: Clinical, histologic, genetic, radiologic discussion of findings and roles of embolosclerotherapy. TEACHING POINTS: 1. Vascular tumors have hypercellular endothelium with infantile hemangioma exhibiting proliferation then involution. Vascular malformations have normal endothelial cell turnover, are present at birth and grow commensurately with age. 2. Current ISSVA and other subclassification schema are summarized in table 1. 3. VMs can appear hypoechoic with monophasic flow on US. VMs are hyperintense on T2-weighted MR, enhance, and are graded based on size and definition. Phlebography classifies VM morphology and venous drainage type. Sclerotherapy efficacy is related to lower grade and type. 4. LMs are divided into macro and microcystic lesions based on cyst size on imaging. Hyperintense on T2 MR, macro and microcystic lesions are optimally treated with sclerotherapy or surgery, respectively. 5. AVMs have high flow on all imaging modalities. Clinical presentation varies from quiescence to cardiac decompensation and dictates treatment. Embolo-sclerotherapy and/or adjunctive surgery offers the best treatment option.

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MATERIALS AND METHODS: The imaging data of 399 patients were retrospectively reviewed. All patients had a 16 slice CTA examination for a valid clinical indication. There were 207 female and 192 male patients with age ranging from 18 to 96 years. Retrospective bilateral renal artery ostium evaluation at the aorta and bilateral renal hilum arterial pedicle angle measurements were performed. Anterior angles were recorded as positive and posterior angles were recorded as negative. Each anatomic vascular information was grouped in 5 degree interval clusters. Additionally, measurements of the aorta and bilateral renal artery diameter and the longitudinal distance of both renal arteries were performed.

CONCLUSION: CT angiography is adequate to demonstrate the renal arterial anatomy, and the location of the renal artery ostium in the aorta and the angles of the arteries in the hilum of the kidney.

Table 1 Classification of Vascular Malformations Vascular Tumors* Infantile Hemangioma/others Vascular Low CM* Malformations* Flow** VM* Cavitary, Type 1- Isolated; Type 2- Normal Spongy, Venous Drainage; Type 3- Drainage Dysmorphic† into Dysplastic Veins; Type 4- Ectasia†† Grade 1 - defined ⫹ ⬍ 5cm; Grade 2 - ill defined or ⬎ 5 cm; Grade 3 - ill defined and ⬎ 5 cm *† LM* Macrocystic; Microcystic* High AVM* Flow** Combined*

* ISSVA; ** Jackson; † Dubois; †† Dubois/Puig; *†Goyal

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Abstract No. 258 Anatomical Patterns and Mortality of Malperfusion in Patients with Acute Aortic Dissection. D.M. Williams, University of Michigan Hospitals, Ann Arbor, MI, USA 䡠 N.L. Dasika 䡠 J.J. Gemmete 䡠 G.R. Upchurch 䡠 H.J. Patel 䡠 G.M. Deeb

CONCLUSION: Interventional treatment is one of the therapeutic options for male varicocele, but the method is limited by the anatomic variants or aberrant supplying vessels, which make catheterization and sclerosis of the internal spermatic vein difficult. Transbrachial approach and knowledge of anatomic variants of the right internal spermatic vein make the procedure easier, especially in the bilateral varicocele.

PURPOSE: Define anatomical patterns and mortality of clinically suspected malperfusion accompanying aortic dissection (AD). MATERIALS AND METHODS: Organ or limb malperfusion was suspected in 79 and 85 patients with acute type A and B AD, respectively. Clinical and angiographic diagnoses of malperfusion were compared, and the mortality of malperfusion syndromes based on arterial pattern and aorta-branch artery pressure gradient was determined. RESULTS: In acute type A AD with clinically suspected malperfusion, angiographically documented malperfusion was present in 61 and absent in 18, with a mortality of 36% and 39%, respectively. In acute type B, malperfusion was present in 61 and absent in 24, with mortality of 16% and 0%, respectively. Clinically suspected mesenteric malperfusion was found in 56/100 patients, renal in 80/132, and lower extremity in 65/76. Clinically unsuspected mesenteric, renal, or lower extremity malperfusion was found in 36, 45, and 28 additional patients, respectively. Mortality was 16% when the aortomesenteric gradient was ⱕ 20 mm Hg, but 28% when it exceeded 20 mm Hg. CONCLUSION: Mortality in patients with malperfusion remains high despite anatomic correction of the malperfusion syndromes. Mesenteric, renal, or lower extremity malperfusion is clinically unsuspected in over 1/3 of patients who have these life-threatening complications. ER and IR personnel should maintain high clinical suspicion of undiagnosed malperfusion and low imaging threshold for malperfusion syndromes in patients with acute AD. Abstract No. 259 Phlebographic Classification of Anatomic Variants in the Right Internal Spermatic Vein. P. Stefano, Az. Osp. S. Camillo-Forlanini Roma, Roma, Lazio, Italy 䡠 A. Paolo 䡠 F. Guido 䡠 R. Giovanni 䡠 A. Maurizio PURPOSE: Male varicocele is a clinical dysfunction caused by a pathological venous reflux. Knowledge of anatomic variants of the internal spermatic vein confluence is fundamental for the technical success of percutaneous treatment. We report an exhaustive depiction of the right internal spermatic vein. MATERIALS AND METHODS: From a retrospective review of 3229 patients treated percutaneously between 1998 and 2003, we extrapolated the phlebographic images of patients with incontinence of the right spermatic vein only. Indication for treatment was presence of pain, absence of a history of trauma e/o seminal fluid alterations. Phlebography was done with transbrachial approach, with hydrophilic guire wire and multipurpose catheter. RESULTS: There were 93 cases of incontinence of the right internal spermatic vein only. In the first group (7 patients 7.5%) the right spermatic vein drains into the renal vein. In the second, 21 (22.5%) drains into renal vein and inferior vena cava, with the first branch showing functional predominance. In 65 patients (69,8%) the confluence was into the inferior vena cava, with a single or a double branch. S96

Abstract No. 260 CT Localization of the Common Femoral Artery (CFA) as a Landmark for CFA Cannulation. B.L. Holloway, Kaiser-Permanente Sunset Medical Center, Los Angeles, CA, USA 䡠 G.G. Vatakencherry PURPOSE: We used contrast-enhanced CT scans of the abdomen and pelvis to determine the relationship of the common femoral artery (CFA) bifurcation to the femoral head. MATERIALS AND METHODS: Patients who had contrastenhanced CT scans of the abdomen and pelvis for various clinical reasons were evaluated retrospectively from 03/ 2006- 08/2006. We divided the femoral head into a superior and inferior half, and recorded the location of the CFA bifurcation with respect to its localization in one of the four following areas: above the femoral head (zone A), within the superior half of the femoral head (zone B), within the inferior half of the femoral head (zone C), or below the femoral head (zone D). RESULTS: 250 patients were evaluated (104 male patients; 146 female patients; mean age 54 years old; age range 18-94 years old). 1 patient (0.004%) had a CFA bifurcation in zone A, 19 patients (8%) had a CFA bifurcation in zone B, 82 patients (33%) had a CFA bifurcation in zone C, and 148 patients (59%) had a CFA bifurcation in zone D. CONCLUSION: Puncture above the center of the femoral head (within zone B) predicts an ideal puncture site in the majority of patients. However, a small number of patients have CFA bifurcations above the center of the femoral head. Therefore, if a CT scan of pelvic region is available, it should be used in planning CFA puncture for interventional procedures.

Imaging: Other Abstract No. 261 Independent Evaluation of a Digital Caliper System within a Common Interventional Fluoroscopy Unit. C.T. Lau, Hospital of the University of Pennsylvania, Philadelphia, PA, USA 䡠 A.A. Patel PURPOSE: Digital calipers are frequently used during fluoroscopically guided interventional radiology procedures. However, little independent validation of different manufacturers’ specifications and claims exists. As a result, the accuracy and precision of these measurements are unclear. In this study, we evaluate the digital caliper system of a commonly used interventional fluoroscopy unit, studying the effects of source-to-object distance, object-to-image distance, image intensifier field of view, parallax, table-toobject distance, automatic and manual calibration on measurement error. MATERIALS AND METHODS: Spot fluoroscopy images of a phantom were obtained on a Siemens Multistar Plus