Transluminally placed endovascular grafts for venous lesions in patients on hemodialysis.

This report summarizes a feasibility study of transluminally placed endovascular grafts (TPEG) using pre-expanded polytetrafluoroethylene (PTFE) to treat venous abnormalities in patients on hemodialysis. Seventeen patients with peripheral (n = 11) or central (n = 6) venous lesions were treated with TPEG devices. Covered Gianturco stents were used for the peripheral lesions and covered Palmaz stents were used for central lesions. Venous abnormalities included vascular rupture after balloon angioplasty or surgical thrombectomy (n = 4), stenosis associated with an aneurysm (n = 2) and occlusive disease and central stenoses not responsive to balloon angioplasty (n = 11). The mean primary patency period was 37 days. The mean secondary patency period was 215 days. At 60, 180, and 360 days the primary and secondary patency rates were 40%, 32%, and 32%, and 70%, 55%, and 39%, respectively. Follow-up studies have shown various outcomes of the implanted TPEG devices, which have included stenoses within the TPEG (n = 2), stenoses central to the TPEG (n = 1), stenoses peripheral to the TPEG (n = 3), acute thrombosis extending to the TPEG without a stenosis (n = 1), graft abandoned with patent TPEG (n = 6), and TPEG patent within primary patency period at last follow-up (n = 4). The TPEG devices, made with pre-expanded PTFE, appear safe in the short term, do not prevent progressive dialysis access site failure, and need to be compared to PTA and endovascular stenting in a randomized prospective trial.

"Accordion" deformity of a tortuous external iliac artery after stent-graft placement.

PURPOSE: To identify a complication of endograft deployment in aneurysmal iliac arteries. CASE REPORT: A 71-year-old man was referred for endovascular treatment of a 60-mm-diameter right common iliac artery aneurysm; however, deployment of a homemade covered stent (Palmaz-Schatz and polytetrafluoroethylene) induced shortening of the tortuous external iliac artery, causing an "accordion" deformity. The anomaly proved difficult to treat with serial Wallstent deployment, because the convolution tightened and migrated caudally with each stent deployed, threatening outflow. Finally, after 3 Wallstents were implanted, the contour of the external iliac artery was straight, and flow was unimpeded. However, 3 weeks later, the external iliac artery had recoiled to its original redundant appearance, but flow remained satisfactory. The aneurysm remains excluded, with satisfactory distal flow after 24 months. CONCLUSIONS: Implanting endografts in redundant, tortuous arterial segments may prove problematic, since induced straightening by the device precipitates kinking in the redundant system. Although treatment may be required in some situations, the vessels may return to a noncompressed state by removing the delivery system and guidewire.

Helical CT in the evaluation of renal colic.

This study assessed the clinical effectiveness of unenhanced helical (spiral) computed tomography (CT) for evaluation of patients presenting with symptoms of renal colic. Two hundred patients with symptoms and signs of renal colic (flank or groin pain, hematuria) were imaged. Unenhanced CT was performed using 5-mm collimation with a pitch of 1.5 to 1.8. Image reconstruction was performed at 3-mm intervals. Exam time was approximately 5 minutes. The financial charge at the study institution was the same as for an intravenous urogram. Clinical follow-up was performed by review of available medical records and patient interviews. The sensitivity for detecting clinically relevant ureteral and bladder calculi was 0.862 (0.95 confidence interval [CI] 0.771 to 0.927), the specificity was 0.914 (0.95 CI 0.837 to 0.962), and the accuracy was 0.89 (0.95 CI 0.833 to 0.931). Helical CT is an effective technique in the evaluation of suspected acute urinary tract obstruction.

Single limb patency of polytetrafluoroethylene dialysis loop grafts maintained by traumatic fistulization.

The purpose of this report is to describe an unusual presentation of obstructive neointimal hyperplastic lesions in loop prosthetic dialysis grafts. The case histories and imaging studies of two patients with partial graft thrombosis are presented. The literature of unexpected fistulae from prosthetic dialysis grafts to adjacent veins is reviewed. Signs and symptoms that would lead a clinician to suspect the diagnosis are emphasized. There were two dialysis grafts with partial thrombosis and arterial limb patency maintained by iatrogenic fistula. These fistulae occurred from the erosion of pseudoaneurysms in one case and an apparent needle stick without pseudoaneurysm in the other. Both grafts had high-grade stenotic lesions affecting the venous outflow. In the first case this was not recognized until the graft reclotted 2 days after thrombectomy. In the most extreme cases of graft/vein fistulae, i.e., partial graft thrombosis with arterial limb patency maintained by the fistula there is always associated venous anastomotic or outflow stenoses which must be addressed.

Aortic and lower-extremity arterial disease: evaluation with MR angiography versus conventional angiography.

PURPOSE: To compare magnetic resonance (MR) angiography with conventional angiography in evaluation of the aorta and lower-extremity arterial system. MATERIALS AND METHODS: Fifty-seven patients were evaluated with femoral conventional and MR angiography. Iliac artery segments were evaluated with two-dimensional and contrast material-enhanced three-dimensional time-of-flight MR angiography. Infrainguinal regions were evaluated with two-dimensional time-of-flight MR angiography with a dedicated lower-extremity coil. Arteries depicted on femoral images were separately interpreted as 20 anatomic segments. Disease classification included normal to moderate disease (0%-50% stenosis), severe stenosis (> 50% stenosis), diffuse disease (more than one severe stenosis), and occlusion. Four readers interpreted the images and rendered treatment recommendations. RESULTS: Substantial to almost perfect interobserver agreement (kappa, 0.66-1.00) was achieved in most cases for MR angiogram interpretation. The three most experienced readers achieved substantial to almost perfect intraobserver agreement (kappa, 0.61-1.00) between conventional and MR angiogram interpretation in most cases. Among three readers, moderate agreement (kappa, 0.43-0.53) was found between treatment recommendations based on conventional versus MR angiographic findings; for the most experienced reader, this agreement was almost perfect (kappa, 0.90). CONCLUSION: For experienced readers, there was substantial to almost perfect agreement between conventional and MR angiographic image interpretations of the aorta and lower-extremity arterial system.

Endovascular stents covered with pre-expanded polytetrafluoroethylene for treatment of iliac artery aneurysms and fistulas.

PURPOSE: This report describes the early clinical experience with use of a transluminally placed endovascular graft (TPEG) covered with pre-expanded polytetrafluoroethylene (PTFE) to treat iliac artery aneurysms and fistulas. MATERIALS AND METHODS: Eight patients with iliac artery aneurysms (n = 7) and common iliac artery to common iliac vein fistula (n = 1) were treated with TPEGs. The iliac artery aneurysms were either common iliac (n = 6) or hypogastric (n = 1). All of the patients had significant comorbid diseases. The TPEG devices were made with pre-expanded PTFE sutured to Palmaz stents and delivered through 10- or 12-F sheaths. RESULTS: The aneurysms were successfully excluded in six of seven patients and the one iliac artery-to-vein fistula was successfully occluded. There were no immediate procedural complications related to the TPEG devices. Follow-up was limited (mean, 12 months), but no stenoses or occlusions of the TPEG devices were detected. The one failure was probably due to the marked tortuousity of the iliac artery, which prevented an adequate seal. CONCLUSION: In the authors' early clinical experience, the use of TPEG devices with pre-expanded PTFE successfully treated iliac artery aneurysms and an iliac artery-to-vein fistula. Although the results are encouraging, longer follow-up is necessary to better evaluate this type of treatment.

MR imaging of the rotator cuff tendon: interobserver agreement and analysis of interpretive errors.

PURPOSE: To evaluate accuracy in interpretation of shoulder magnetic resonance (MR) images and interobserver agreement and to characterize the types of errors. MATERIALS AND METHODS: Five radiologists with varying experience independently and retrospectively twice interpreted the MR images of 222 symptomatic patients who underwent both MR imaging and shoulder arthroscopy. The first interpretation was a blind review; the second was with knowledge of the arthroscopic findings. RESULTS: For full-thickness tears, the sensitivity, specificity, and accuracy were 84%-96%, 94%-98%, and 92%-97%, respectively, and for partial tears, 35%-44%, 85%-97%, and 77%-87%, respectively. There was no statistically significant difference between readers in the detection of partial or full-thickness tears. There was a statistically significant difference between readers in the no-tear category. Cohen kappa values generally indicated improved interobserver agreement proportional to the readers' experience (full-thickness tears, 0.731-0.881; partial tears, 0.168-0.443). CONCLUSION: Diagnosis of a full-thickness tear can be learned to a high degree of accuracy. Despite the radiologist's level of experience and knowledge of the arthroscopic findings, the sensitivity for diagnosis of partial tears is poor.

Evaluation of the iliac arteries: comparison of two-dimensional time of flight magnetic resonance angiography with cardiac compensated fast gradient recalled echo and contrast-enhanced three-dimensional time of flight magnetic resonance angiography.

We compared dynamic contrast-enhanced three-dimensional time of flight (3DTOF) magnetic resonance angiography (MRA) with two-dimensional time of flight (2DTOF) MRA with cardiac compensated fast gradient recalled echo (C-MON) and conventional angiography (CA) when it was available. C-MON re-orders the normal data acquisition to minimize ghosting artifacts generated by pulsatile flow. The initial phase of the study involved optimization of parameters and comparison C-MON with no C = MON in eight patients and volunteers. The final phase of the study involved 53 patients who were imaged with contrast-enhanced 3DTOF MRA and 2DTOF MRA with C-MON. Thirty of these patients also had CA. In the initial phase, 2DTOF MRA with C-MON was found to be equal (n = 3) or superior (n = 5) to 2DTOF without C-MON. In the final phase, the agreement among all imaging modalities varied from substantial to almost perfect (Cohen's kappa = .6-.83). The lowest agreement was using 2DTOF to evaluate the external iliac segments. The among suggested treatments varied from substantial to almost perfect for all imaging modalities (Cohen's kappa = .73-93). The diagnostic efficacies of 2DTOF with C-MON and contrast-enhanced 3DTOF were high overall, with the lowest value being a specificity of 63% for one reader in the evaluation of an external iliac segment using 2DTOF. In summary, 2DTOF with C-MON helped to eliminate artifacts due to pulsatility in the iliac arterial segments. In our experience, both dynamic contrast-enhanced 3DTOF MRA and 2DTOF MRA with C-MON performed well in the evaluation of the iliac arteries. Both studies have high interobeserver agreement and high diagnostic efficacy. Contrast-enhanced 3DTOF MRA should be reserved for situations in which the iliac vessels are extremely tortuous or occluded or the external iliac segments are poorly seen.

Local delivery of heparin with balloon angioplasty: results of a prospective randomized trial.

PURPOSE: To evaluate the effectiveness of local delivery of heparin via hydrogel-coated balloons in the treatment of vascular stenoses associated with hemodialysis access. MATERIALS AND METHODS: This was a randomized, prospective trial comparing treatment with hydrogel-coated balloon catheters delivered with heparin coating (n = 33) and without (n = 26). All patients were undergoing hemodialysis, and all stenoses involved the venous anastomosis of a dialysis graft or a native vein. The heparin-treated balloons were soaked in concentrated heparin and delivered in a protected manner to help prevent washout of heparin. RESULTS: The mean primary patencies were 143 days with heparin treatment and 214 days without heparin (P = .174). The mean assisted primary patencies were 165 days with heparin and 194 days without (P = .315). The mean secondary patencies were 351 days with heparin and 384 without (P = .81). CONCLUSION: In this population with this technique, the treatment outcome of venous outflow stenosis in patients with dialysis grafts is not improved with local delivery of heparin.

MR imaging of silicone breast implants: evaluation of prospective and retrospective interpretations and interobserver agreement.

MR imaging was used to evaluate the integrity of silicone breast implants in 54 women with 108 implants. MR images were interpreted by relatively inexperienced readers who tried to reproduce the experiences reported in the literature. The study examines the interobserver agreement using different diagnostic signs and the influence of experience on interpretation errors. Prospective and retrospective interpretations were compared with surgical findings at the time of explanation. Diagnostic indicators, including the linguine sign, the inverted tear drop sign, the C sign, water droplets mixed with silicone, and extracapsular globules of silicone, were evaluated for diagnostic efficacy and interobserver agreement. The prospective sensitivity and specificity were 87% and 78%, respectively. With the retrospective interpretations, the sensitivity and specificity increased to 93% and 92%, respectively. Most of the prospective false-positive interpretations were due to misinterpreting radial folds as signs of implant rupture. Six implants interpreted retrospectively as false positives had gross amounts of silicone around the implants at surgery but there were no obvious rents in the implant shells. There was fair to excellent interobserver agreement with the individual diagnostic signs except for extracapsular globules of silicone. All of the signs had specificities of greater than 90%. The sensitivities of the individual signs were less than the overall retrospective sensitivity. With experience, the sensitivity improved from 87% to 93% and the specificity improved from 78% to 92%. This study helps substantiate the use of diagnostic signs used by other authors to detect silicone loss from breast implants by MR imaging; however, questions remain as to the clinical role of MR imaging in evaluating implants for silicone loss.

Percutaneous transluminal angioplasty versus endovascular stent placement in the treatment of venous stenoses in patients undergoing hemodialysis: intermediate results.

PURPOSE: This report describes intermediate findings from an ongoing prospective randomized trial comparing the results of percutaneous transluminal angioplasty (PTA) with results of endovascular stent placement in patients undergoing hemodialysis. PATIENTS AND METHODS: Among 87 consecutive patients with venous stenoses or occlusions, 47 (54%) were treated with PTA alone and 40 (46%) were treated with PTA and stent placement. RESULTS: For peripheral sites, the primary patency rates for PTA at 60, 180, and 360 days were 55%, 31%, and 10%, respectively, and for stents were 36%, 27%, and 11%, respectively (P = .6528). The secondary patency rates for PTA at 60, 180, and 360 days were 94%, 80%, and 71%, respectively, and for stents were 73%, 64%, and 64%, respectively (P = .1677). For central sites, the primary patency rates for PTA at 60, 180, and 360 days were 81%, 23%, and 12%, respectively, and for stents were 67%, 11%, and 11%, respectively (P = .4595). The secondary patency rates for PTA were 100% at each interval, and for stents were 100%, 89%, and 78%, respectively (P = .5408). CONCLUSION: Intermediate results suggest that, overall, there is no difference in the patency rates for peripheral venous stenoses in dialysis patients treated with PTA or PTA and endovascular stent placement. At this time, the numbers of patients are too small to conclude if certain sites such as larger central veins will respond better to one treatment or the other.

The role of percutaneous needle biopsies in the original diagnosis of lymphoma: a prospective evaluation.

PURPOSE: A prospective evaluation to determine if percutaneous needle biopsy yields enough tissue to establish the diagnosis of lymphoma and initiate therapy. PATIENTS AND METHODS: Lymphoma was diagnosed in 43 patients for the first time. Patients underwent either a core needle biopsy (n = 41) or an aspiration-type needle biopsy (n = 2) performed with imaging guidance. Immunochemical studies were performed on specimens from 39 of 43 patients (91%); flow cytometry was performed formed on specimens from 10 patients (23%). Patient progress was followed to see if biopsy results were used as a basis for treatment or if additional material was obtained with an open surgical procedure. RESULTS: On the basis of treatment decisions, needle biopsy results were sufficient for a diagnosis to be made in 36 of 43 patients (84%). In seven patients (16%), needle biopsy specimens were considered nondiagnostic, suspicious for lymphoma, or insufficient. None of the 43 patients responded to therapy in a manner that suggested the diagnosis of lymphoma to be incorrect. CONCLUSION: Image-guided needle biopsy should be the first procedure performed in the diagnosis of lymphoma, except in easily accessible superficial neck, inguinal, and axillary nodal sites.

Role of prenatal ultrasonography in women with positive screen for Down syndrome on the basis of maternal serum markers.

OBJECTIVE: Our purpose was to evaluate the usefulness of prenatal ultrasonography among women with a positive screen for fetal Down syndrome on the basis of three biochemical markers--maternal serum alpha-fetoprotein, human chorionic gonadotropin, and unconjugated estriol. STUDY DESIGN: A total of 395 women underwent prenatal ultrasonography at a single institution after being identified as screen positive (midtrimester risk > or = 1:195) on the basis of triple-marker screening between 15 and 18 weeks. Ultrasonographic findings were compared with the biochemical markers and the eventual fetal outcome for these patients. Ultrasonographic abnormalities that were evaluated included structural defects, nuchal thickening or cystic hygroma, echogenic bowel, cerebral ventricular dilatation, pyelectasis, and shortened femur. RESULTS: Among 395 patients, 374 (94.7%) had normal karyotype by genetic amniocentesis (n = 232) or postnatal follow-up (n = 142), 18 (4.5%) proved to have Down syndrome, and three had other karyotypic abnormalities. One or more ultrasonographic abnormalities were found in nine of 18 (50%) with Down syndrome compared to 27 of 377 (7.2%) other fetuses (p < 0.001). Fetuses with abnormal ultrasonography results included three with other chromosome abnormalities and five with nonchromosomal anomalies. An abnormal ultrasonography result increased the risk of Down syndrome by 5.6-fold (25% from 4.5%) and a negative result reduced the risk by 45% (2.5% from 4.5%). The value of ultrasonography is further enhanced when all chromosome abnormalities and nonchromosomal anomalies are considered. CONCLUSION: Abnormal ultrasonographic findings increase the risk for Down syndrome, whereas normal findings are less predictive of normalcy. After correction for inaccurate menstrual dates, genetic amniocentesis should be offered in spite of a normal ultrasonography result among women with positive triple screen.

Lower extremities: MR angiography with a unilateral telescopic phased-array coil.

In a comparison of conventional and magnetic resonance (MR) angiography of the lower extremities, MR imaging was performed with extremity and body coils and a unilateral six-coil telescopic phased-array coil. In one of seven volunteers, average signal-to-noise ratio was 140% higher with the latter (p < .01), only three of five stations were necessary, and examination time was decreased 50%. In the four patients, correlation in findings was 100%.

Rotator cuff tendon tears: evaluation with fat-suppressed MR imaging with arthroscopic correlation in 100 patients.

PURPOSE: To evaluate the diagnostic accuracy of fat-suppressed magnetic resonance (MR) imaging of rotator cuff tears in a large symptomatic population. MATERIALS AND METHODS: One hundred patients underwent both MR imaging and arthroscopy of the shoulder. Ninety-two patients underwent fat-suppressed conventional spin-echo MR imaging (repetition time msec/echo time msec = 2,500/20, 60), and eight patients underwent fat-suppressed, fast spin-echo MR imaging (2,000/80). RESULTS: With data combined for complete and partial tears of the rotator cuff (n = 31), MR imaging had an accuracy of 93%; sensitivity, 84%; and specificity, 97%. Seventeen of 20 complete tears and nine of 11 partial tears were properly identified with MR imaging. Two partial tears were not detected and three complete tears were incorrectly called partial tears at MR imaging. Of two false-positive MR imaging findings, one was called a complete tear and the other, a partial tear. CONCLUSION: Fat-suppressed MR imaging has high diagnostic accuracy in evaluating tears of the rotator cuff tendon.

Azygous continuation of the interrupted inferior vena cava: a clue to prenatal diagnosis of the cardiosplenic syndromes.

We reviewed the prenatal sonographic findings in 11 consecutive fetuses diagnosed as having abdominal situs inversus (stomach on the right) at a single institution. Interruption of the inferior vena cava with azygous continuation was diagnosed by the "double vessel" sign. This sign was considered to be present in nine cases, including all eight fetuses who proved to have the polysplenia syndrome. The only false positive diagnosis of IVC interruption with azygous continuation was made prospectively in one fetus with asplenia. At autopsy, this fetus showed a large left-sided superior vena cava. We conclude that, in combination with cardiac anomalies or situs abnormalities, interruption of the IVC with azygous continuation should suggest a specific diagnosis of a cardiosplenic syndrome, especially polysplenia. This information should be helpful in patient counseling and management.