Superior mesenteric vein thrombosis with radiologically occult cause: a retrospective study of 43 cases

OBJECTIVE

Our purpose was to examine the clinical presentation, imaging appearance, etiology, and clinical outcome in patients who had acute thrombosis of the superior mesenteric vein with radiologically occult cause.

CONCLUSION

The most common predisposing factors in superior mesenteric vein thrombosis with radiologically occult cause are recent abdominal surgery, infection, and hypercoagulable states. Although no correlation was noted between risk factor and outcome, the presence of bowel wall thickening and mesenteric congestion on CT or MR imaging was associated with the development of bowel ischemia. Prognosis is good in this group of patients, with a mortality of only 7%, although bowel ischemia was noted in 21%.

Sural artery pseudoaneurysms after knee arthroscopy: treatment with transcatheter embolization

Vascular injury of the popliteal artery or its branches after knee arthroscopy is a rare but potentially devastating complication. We report two cases of sural artery branch pseudoaneurysms resulting from knee arthroscopy. Both patients were successfully treated with transcatheter embolization of the pseudoaneurysms. the diagnosis and treatment options of this unusual injury are discussed.

Use of endovascular stents for the treatment of abdominal aortic aneurysm

The conventional open surgical repair of abdominal aortic aneurysms is a well-established and durable procedure. However, as with all other major abdominal surgical operations, there are associated morbidities. Both mortality and morbidity increase significantly with advanced patient age and associated comorbid conditions. Endovascular aortic stent-grafts offer a significantly less invasive alternative to conventional open-surgical repair. Patients previously considered unsuitable for open repair can often receive treatment for aneurysms with endovascular techniques. The US Food and Drug Administration has recently approved two endovascular stent-graft devices for use within the United States.

Advances in gastrointestinal intervention: the treatment of gastroduodenal and colorectal obstructions with metallic stents

Metallic stents are currently an established component of the endoluminal treatment of stenoses within the blood vessels, bile ducts, esophagus, trachea, and bronchi. With the development of newer stent designs and delivery systems and the general momentum toward minimally invasive therapies, metallic stent placement has expanded into the nonsurgical therapy for gastroduodenal and colorectal obstructions. The use of metallic stents within the stomach, duodenum, or colon is intended not to be curative but to provide nonsurgical palliation for the symptoms of gastric or colonic obstruction. This palliation may be intended for the life of the patient in the case of unresectable disease or as a temporizing procedure prior to a definitive surgical procedure. In the latter clinical scenario, the benefits of a minimally invasive intestinal decompression procedure include (a) quick and noninvasive relief of the intestinal obstruction in an acutely ill patient that obviates a more extensive procedure; (b) allowance of time to improve a patient's overall medical condition and thus to allow a patient to better tolerate the definitive surgical procedure; and (c) reduction of the complexity of the definitive procedure by eliminating the need for staged procedures and allowing the definitive procedure to be performed at one setting.

Primary Gianturco stent placement for inferior vena cava abnormalities following liver transplantation

PURPOSE

To determine the efficacy of primary Gianturco stent placement for patients with inferior vena caval (IVC) abnormalities following liver transplantation.

MATERIALS AND METHODS

From August 1996 through March 1999, nine adult patients developed significant IVC abnormalities following liver transplantation. Patients were referred for vena cavography on the basis of abnormal clinical findings, laboratory values, liver biopsy results, Doppler findings, or a combination. Those patients demonstrating a significant caval or hepatic venous gradient were treated with primary Gianturco stent placement. Patients were followed clinically (nine patients), with duplex ultrasound (nine patients), vena cavography (four patients), and biopsy (seven patients).

RESULTS

Original pressure gradients ranged from 3 to 14 mm Hg, with a mean of 9 mm Hg. Gradients were reduced to 3 mm Hg or less in all nine patients; presenting signs and symptoms either resolved or improved in eight of nine patients. The ninth patient required repeated transplantation 2 days later. A second patient died 433 days after stent placement of recurrent hepatitis C. Another initially improved following caval stent placement, but underwent repeated transplantation 7 days later due to hepatic necrosis from hepatic arterial thrombosis. Follow-up for the remaining six patients has averaged 491 days, with no clinical, venographic, or ultrasound evidence for recurrent caval stenosis.

CONCLUSIONS

Intermediate term results suggest that primary Gianturco stent placement for IVC stenosis, compression, or torsion resulting after liver transplantation is safe and effective.

Liver metastases: comparison of current MR techniques and spiral CT during arterial portography for detection in 20 surgically staged cases

PURPOSE

To compare spiral computed tomography during arterial portography (CTAP) with current magnetic resonance (MR) imaging, including hepatic arterial-dominant phase, gadolinium-enhanced, spoiled gradient-echo imaging, for the prospective detection of liver metastases in 20 patients who subsequently underwent surgery to confirm findings.

MATERIALS AND METHODS

Twenty patients underwent spiral CTAP and MR imaging within 1 week. Spiral CTAP and MR images were interpreted separately in blinded fashion. All patients subsequently had intraoperative confirmation. Sensitivity, specificity, and positive and negative predictive values were determined for lesion detection and segmental distribution.

RESULTS

CTAP and MR images demonstrated, respectively, 54 and 60 true-positive lesions, six and one false-positive lesions, 15 and 22 true-negative (i.e., benign) lesions, and eight and two false-negative lesions. CTAP and MR images demonstrated, respectively, 57 and 62 true-positive segmental involvements, six and one false-positive segmental involvements, 89 and 95 true-negative segmental involvements, and eight and two false-negative segmental involvements. No significant difference in lesion detection was observed.

CONCLUSION

Spiral CTAP and MR imaging were approximately equivalent for lesion detection in patients who were evaluated preoperatively for resection of liver metastases. The lower cost and fewer problems with artifacts may suggest that MR imaging is the preferred modality for preoperative assessment of patients for surgical treatment of liver metastases.

Resource requirements for interventional radiologic management of long-term ambulatory hemodialysis patients

OBJECTIVE

The purpose of this study was to determine how many and what type of procedures a vascular and interventional radiology service should provide for patients at ambulatory-patient dialysis centers and to determine the necessary resource requirements. These data may provide a realistic starting point for those engaged in the planning and provision of contractual services to dialysis centers.

MATERIALS AND METHODS

Patient records at three dialysis centers for a recent 3-year period were examined, and demographic and clinical data were recorded. Records were cross-correlated with records from the vascular and interventional radiology service that had contractually provided all dialysis-related procedures. These data generated a monthly procedure volume and case mix per 100 dialysis patients. Facility usage times for 121 dialysis-related procedures were obtained prospectively and used to calculate the expected resources needed to service the dialysis patients.

RESULTS

The three centers provided 5795 hemodialysis-months to 386 patients. Of the 386 patients over the 36-month period, 101 died and 92 transferred from the centers. Three hundred and sixteen patients required 1580 interventional procedures. Monthly procedure volume per 100 dialysis patients averaged 27.1 procedures. Observed procedure times were used to calculate expected room-time hours required to service the monthly procedural volume and case mix per 100 dialysis patients.

CONCLUSION

On average, 500 ambulatory dialysis patients will require the full-time use of an interventional suite and the services of a full-time technologist, nurse, and physician to provide necessary dialysis-related procedures. If resources cannot accommodate this volume, the quality and timeliness of care for these patients is jeopardized.

Magnetic resonance imaging of the abdominal aorta and iliac vessels using combined 3-D gadolinium-enhanced MRA and gadolinium-enhanced fat-suppressed spoiled gradient echo sequences

This study evaluates a combined protocol consisting of breath hold immediate post gadolinium 3-D gradient echo MR angiography and blood pool phase gadolinium-enhanced breath hold 2-D fat-suppressed spoiled gradient echo (SGE) sequences in the examination of diseases of the abdominal aorta and iliac vessels. Thirty-two patients with suspected disease of the abdominal aorta, major aortic branches, or iliac vessels underwent MR angiographic study from January 1996 to January 1997. Examinations were performed on a 1.5 T MR imager using 2-D axial SGE, coronal 3-D fast imaging in steady state precession (3-D FISP) following bolus administration of 40 mL of gadolinium, and axial and coronal blood pool phase gadolinium-enhanced fat-suppressed SGE. Post-processed data, including 3-D reconstructions using maximum intensity projection (MIP), targeted MIP, and multiplanar reconstruction (MPR) were evaluated. MR findings in all patients were correlated as follows: surgery (13 patients), angiography (11 patients), contrast enhanced CT (3 patients), non-contrast enhanced CT (1 patient), color doppler US (2 patients), and previous MR study (2 patients). MR findings correlated closely with findings at surgery or other imaging studies in 31 of 32 patients. One patient had renal artery occlusion that was misinterpreted as mild stenosis. The following vascular diseases were present: aneurysm disease [10 patients: aortic aneurysm (8 patients), inflammatory aneurysm (2 patients)], thoracoabdominal aortic dissection (2 patients), arteriovenous fistula (1 patient), stenoses and/or occlusion of the abdominal aorta, major aortic branches and iliac vessels [12 patients: stenoses and/or occlusion of the abdominal aorta with stenoses of the iliac vessels (9 patients), renal artery stenosis (2 patients), occlusion of the abdominal aorta (1 patient)], and occluded artery to pancreatic transplant artery (1 patient). Five patients had normal studies. The 3-D FISP technique accurately defined the luminal contours of vessels, allowing precise depiction of vessel stenosis (i.e., renal artery stenosis or common iliac artery stenosis) and clear demonstration of relationship of aortic branch vessels (i.e., renal arteries) to underlying aortic pathology (i.e., aortic aneurysm or dissection). Blood pool phase gadolinium-enhanced fat-suppressed SGE images were useful in the evaluation of the external surface of vessel walls, and providing accurate measurement of aneurysm diameter and other associated vascular entities (i.e., inflammatory aneurysm, left-sided IVC). Targeted MIP or MPR reconstruction were important for assessing stenoses of medium sized vessels such as renal arteries and branches of the iliac arteries, and for identifying accessory arteries. The combination of immediate post gadolinium 3-D FISP and blood pool phase gadolinium-enhanced fat-suppressed SGE is useful in the evaluation of the abdominal aorta, major aortic branches and iliac vessels. Immediate post gadolinium 3-D FISP images provides diagnostically useful information regarding vessel luminal contour, while blood pool phase gadolinium-enhanced fat-suppressed SGE provides ancillary information on the vessel wall and surrounding tissue.

Decision-analysis of transjugular intrahepatic portosystemic shunt versus distal splenorenal shunt for portal hypertension

Transjugular intrahepatic portosystemic shunt (TIPS) and surgical distal splenorenal shunt (DSRS) are treatments for complications of portal hypertension. TIPS is widely used because it is relatively easy to place. Because TIPS may malfunction over time, it is unclear whether TIPS is superior to DSRS in patients with Child's class A cirrhosis who enjoy a longer survival. This study compared the cost-effectiveness of TIPS to DSRS for portal hypertension in Child's class A cirrhosis. A decision analysis model was used to evaluate the number of procedures, life expectancy, and costs over the first 2 years in patients with Child's class A cirrhosis who underwent a TIPS or DSRS. Patients who received TIPS survived 1.96 years, required 1.7 procedures, and incurred $41,685 in costs. Patients who underwent a DSRS survived 1.86 years, required 1.0 procedure, and incurred $26,951 in costs. The cost-effectiveness of TIPS compared with DSRS was $147,340 per life-year saved. Adjusting the rate of TIPS dysfunction, 1-year survival, or the number of ultrasounds to detect TIPS dysfunction did not change the results. In patients with Child's class A cirrhosis, DSRS is a more cost-effective treatment than TIPS. Until the results of a randomized controlled trial comparing TIPS with DSRS are available, TIPS should be regarded as experimental and prohibitively expensive in Child's class A cirrhosis.

Bronchial artery embolization for the treatment of hemoptysis in patients with cystic fibrosis

Hemoptysis is common in patients with cystic fibrosis (CF). Bleeding may vary in severity, ranging from minor blood-streaking of sputum to expectoration of significant quantities of blood. Major hemoptysis, defined as bleeding greater than 240 ml/24 h, represents a medical emergency. Bronchial artery embolization (BAE) is one of the treatment options for hemoptysis. We reviewed the 10-yr experience at the University of North Carolina Hospitals in the treatment of hemoptysis by BAE. Eighteen patients with CF were hospitalized on 29 occasions and underwent 36 BAE procedures for the control of hemoptysis. Most patients (n = 11) had very severe lung disease (FEV1 < 35%) with a high incidence (n = 9, 50%) of multi-drug-resistant bacteria. Fifteen patients (n = 33 procedures) were followed for a mean of approximately 22 mo after BAE. The overall efficacy of BAE for initial control of hemoptysis was 75% (n = 22) after one session, 89% (n = 26) after two sessions, and 93% (n = 27) after three sessions. The overall recurrence rate per episode was 46% (12/26 presentations in four patients) with a mean time for recurrence of approximately 12 mo. There was a high incidence (75%) of bleeding from nonbronchial systemic collateral vessels among patients (n = 7) who had undergone a previous BAE. There were two deaths associated with massive hemoptysis despite BAE. Three patients had transient neurologic deficits during BAE. We concluded that BAE is a relatively safe and effective means of treating significant hemoptysis in patients with CF.

Malignant hepatic tumors: changes on MRI after hepatic arterial chemoembolization--preliminary findings

This study describes the MR appearances of malignant hypervascular liver lesions pre- and post-hepatic-arterial chemoembolization, with correlation to serial imaging and clinical responses. Eight patients with malignant hypervascular liver lesions underwent pretreatment and posttreatment MR examination on a 1.5-T MR imager. MR sequences included T1-weighted spoiled gradient echo (SGE), T2-weighted fat-suppressed spin echo or turbo spin echo, and dynamic gadolinium-enhanced SGE images. All patients underwent pretreatment, initial posttreatment, and subsequent posttreatment MR studies. The histology of primary tumors included various types of hepatocellular carcinoma (HCC) (four patients: fibrolamellar HCC [one patient], HCC [two patients], mixed HCC/cholangiocarcinoma [one patient]) and liver metastases (four patients: untyped islet cell tumor [two patients], gastrinoma [one patient], carcinoid [one patient]). Response to chemoembolization was determined by three assessments: MR response, serial imaging response, and clinical response. The appearance of MR response to chemoembolization was determined based on the correlation with clinical and serial imaging response. The MR response of lesions that showed good clinical response included: increase in signal intensity on T1-weighted images (three patients), decrease in signal intensity on T2-weighted images (three patients), and negligible or minimal enhancement on immediate postgadolinium images (four patients) after chemoembolization. The most marked change in lesion appearance was observed in lesions < or = 1 cm, which had intense homogeneous enhancement on pretreatment MR studies and negligible enhancement on initial posttreatment MR examinations. MR response of lesions that showed moderate clinical response demonstrated a variety of lesion appearances from substantial change to minimal change. MR response of lesions that showed poor clinical response demonstrated no change in lesion appearances compared with the pretreatment MR study. Our results demonstrated change in appearance of liver lesions between pre- and post-hepatic-arterial chemoembolization MR studies. MR response correlated with response determined by serial imaging studies and clinical findings.

Prospective randomized comparison of surgical versus endovascular management of thrombosed dialysis access grafts

PURPOSE

Salvage of thrombosed prosthetic dialysis shunts can be performed using surgical or endovascular techniques. A prospective randomized trial was designed to compare the efficacy of these two methods in restoring dialysis access function.

METHODS

One hundred fifteen patients with thrombosed dialysis shunts were randomized prospectively to surgical (n = 56) or endovascular (n = 59) therapy. In the surgical group, salvage was attempted with thrombectomy alone in 22% and with thrombectomy plus graft revision in 78%. In the endovascular group, graft function was restored with mechanical (82%) or thrombolytic (18%) graft thrombectomy followed by percutaneous angioplasty.

RESULTS

Stenosis limited to the venous anastomotic area was the cause of shunt thrombosis in 55% of patients, and long-segment venous outflow stenosis or occlusion was the cause in 30%. In 83% of the surgical group and in 72% of the endovascular group, graft function was immediately restored (p = NS). The postoperative graft function rate was significantly better in the surgical group (p < 0.05). Thirty-six percent of grafts managed surgically remained functional at 6 months and 25% at 12 months. In the endovascular group, 11% were functional at 6 months and 9% by 12 months. Patients with long-segment venous outflow stenosis or occlusion had a significantly worse patency rate than those with venous anastomotic stenosis (p < 0.05).

CONCLUSIONS

Neither surgical nor endovascular management resulted in long-term function for the majority of shunts after thrombosis. However, surgical management resulted in significantly longer primary patency in this patient population, supporting its use as the primary method of management in most patients in whom shunt thrombosis develops.

Endovascular repair of peripheral aneurysms, pseudoaneurysms, and arteriovenous fistulas

Endovascular repair of peripheral arterial lesions was performed in 10 patients including two iliac aneurysms, two iliac anastomotic pseudoaneurysms, one subclavian pseudoaneurysm, one axillary anastomotic disruption, two prosthetic pseudoaneurysms, and two posttraumatic arteriovenous (AV) fistulas. The indications for repair were aneurysm size in five cases, massive hematoma in one, threatened prosthetic dialysis graft in two, venous hypertension with non-healing ulcer in one, and arm pain in one. Vascular access was obtained through surgical cutdown in all cases, via the femoral artery in five patients, the proximal brachial artery in three and a prosthetic graft in two. Stented prosthetic grafts were used in five cases (1 polyester and polytetrafluoroethylene 4 [PTFE]), and PTFE-covered stents in five cases. Concomitant procedures were done in four patients including two open repairs of a common femoral artery aneurysm, a transluminal dilatation of a proximal aortic anastomotic stenosis, and an iliac artery transluminal angioplasty. Eight of 10 cases were technically successful. Completion arteriography revealed complete exclusion of all lesions, except for one minimal proximal stented graft leak in a pseudoaneurysm, and an incomplete obliteration of an AV fistula. No complications occurred. Operative time ranged from 45 min to 5 hours. Postoperative hospital stay was 1 day in five patients, 2 days in three patients, and 4 days in two patients. Follow-up contrast CT scan, arteriography, or duplex scanning demonstrated complete exclusion of all lesions except an AV fistula, and decrease in size in three aneurysms. The proximal leak initially present in a stented graft resolved. All grafts and covered stents remained patent at 2-19 months of followup. Endovascular exclusion of peripheral arterial aneurysms, pseudoaneurysms, and AV fistulas can be done with a high degree of technical success, low morbidity, and short hospital stay. Short-term follow up is encouraging, however, long term follow up of these procedures is warranted to assess durability of the repair and absence of complications.

Comparison of measures for prospective identification of venous stenoses

OBJECTIVE

To compare two methods, venous dialysis pressure (VDP) and intra-access static flow pressure (VPO), for the prospective identification of venous stenoses in high-risk PTFE grafts.

DESIGN

Comparative.

SAMPLE/SETTING

Twenty patients with upper extremity loop grafts in an outpatient chronic hemodialysis population.

METHODS

VDP and VPO were measured for three consecutive treatments within subjects followed by angiography. VDP > 150 mmHg/200 ml/min, VPO > 0.40, and stenoses > 50% were considered positive findings.

RESULTS

In paired t-tests, VPO identified elevated venous pressure more frequently than VDP in patients positive on angiography (mean difference = 77.8%, p < 0.0001). Frequency analysis yielded a sensitivity of 36% for VDP and 93% for VPO (p < 0.05).

CONCLUSION

This study found that while VDP is the simpler method to use, VPO is significantly more accurate at predicting venous stenoses.

The efficacy of percutaneous cholecystostomy in critically ill patients

Percutaneous cholecystostomy (PC) has been proposed as a method of biliary decompression in critically ill patients with acute cholecystitis. We evaluated the efficacy of PC in this setting. The charts of 33 critically ill patients (mean age 52, range 5-87) who underwent PC for suspected acute cholecystitis were retrospectively examined. Univariate analysis was performed to identify which patients might benefit from PC. PC was technically successful in all patients with no direct mortality or major complications. Failure to improve within 24 hours was associated with increased mortality (P = 0.02). A total of 22/33 patients improved, 17/33 survived, and 8/33 required surgery. PC delayed definitive operation in two patients. Cholelithiasis was associated with surgical intervention (P = 0.01) but not increased mortality. Favorable prognosticators for survival included gallbladder dilatation (P = 0.01), pericholecystic fluid (P = 0.01), and absence of a pulmonary artery catheter (P = 0.02). Predictors of improvement included gallbladder nonvisualization on hepatobiliary scan (P = 0.047), positive bile cultures (P = 0.017), and initial drainage of < / = 100 cc (P = 0.009). Age, laboratory data, the use of total parenteral nutrition, and intubation did not predict outcome. Nine positive bile cultures prompted antibiotic changes in five cases. Finally, PC was less expensive than open cholecystostomy ($1620 versus $3155). PC is a safe, cost-effective, minimally invasive procedure that has diagnostic and therapeutic value in critically ill patients with acute cholecystitis. The involvement of a general surgeon is important to ensure that those patients who do not improve within 24 hours receive early surgical intervention and provide long-term definitive care for those patients with cholelithiasis.

Malignant liver lesions: comparison of spiral CT arterial portography and MR imaging for diagnostic accuracy, cost, and effect on patient management

We compared two imaging techniques, spiral CT arterial portography (CTAP) and MR imaging, for diagnostic accuracy, procedural cost, and effect on management of 26 patients referred for hepatic surgery for suspected limited malignant liver disease. CTAP and MR imaging were done within a 1-week period (19 within 24 hours); the results of the studies were interpreted prospectively by separate reviewers. Surgical data were evaluated in conjunction with imaging data in 10 patients. Lesion detection and segmental involvement were determined and sensitivity and specificity were calculated. Procedural cost was determined from hospital billing codes. Effect on patient management was determined by the referring oncologic surgeon. CTAP and MR imaging showed 185 and 176 true-positive malignant lesions, 15 and zero false-positive malignant lesions, zero and 18 true-negative malignant lesions, and 13 and 22 false-negative malignant lesions, respectively. CTAP and MR imaging showed 107 and 105 true-positive segments, 11 and zero false-positive segments, 80 and 91 true-negative segments, and four and six false-negative segments, respectively. There was a significant difference in specificity of segmental involvement between MR imaging (1.0 +/- 0) compared with CTAP (0.88 +/- 0.05), P = .03. Total procedural cost was $3,499 for CTAP and $1,224 for MR imaging. CTAP findings did not change patient management over MR imaging findings in any patient, whereas MR imaging findings resulted in a change in patient management over CTAP findings in seven patients (P = .015). The results of our study suggest that MR imaging has higher diagnostic accuracy and greater effect on patient management than CTAP does and is 64% less expensive.

An aortic aneurysm model for the evaluation of endovascular exclusion prostheses

PURPOSE

The purpose of this study was to develop an aortic aneurysm (AA) model with a predictable tendency for rupture for the evaluation of the efficacy of endovascular prostheses in preventing rupture and their long-term outcome after implantation.

METHODS

An infrarenal AA measuring two to three times the diameter of the proximal aorta was created in 18 dogs with a full-thickness patch of jejunum. Seven dogs were allowed to survive without aneurysm exclusion. In 11 dogs the aneurysm was immediately excluded with a stented 8 mm Dacron graft mounted in a 14F delivery system introduced through the femoral artery with aortographic guidance. The pressure differential between the aorta and the excluded aneurysm was measured, and angiography, necropsy, and histologic examination were performed at 3- and 6-month survival.

RESULTS

All animals survived aneurysm implantation. Without aneurysm exclusion, six dogs died of rupture within 1 to 6 days of surgery. In three dogs the exclusion failed because of graft-to-aorta size mismatch or misplacement demonstrated on angiography and by a low pressure differential between the aorta and the aneurysm (< 5 mm Hg); all three dogs died of rupture within 4 days. In eight dogs the aneurysm was successfully excluded on the basis of angiography results, with a mean aorta-to-aneurysm pressure differential of 51 mm Hg. Two dogs were killed at 1 and 6 days after surgery because of paraplegia produced by graft thrombosis because of kinking but without evidence of aneurysm rupture. Six dogs survived on a long-term basis, and angiography and necropsy performed at 3 and 6 months revealed patent grafts without migration, reduction in aneurysm size, no flow in the excluded lumbar arteries in five of six animals, and complete incorporation of Dacron graft and stents. No evidence of graft infection was found in any animal. The survival rate was significantly better (p < 0.023) in dogs with successfully excluded aneurysms (n = 6) compared with that in dogs without exclusion or with failed aneurysm exclusion (n = 7).

CONCLUSION

This aneurysm model demonstrates that without effective aneurysm exclusion all animals die of rupture and that successfully placed endovascular prostheses can prevent AA rupture with long-term graft patency and stability. Endovascular aortic Dacron grafts in dogs undergo complete incorporation at 3 months from implantation. This aneurysm model is useful for the evaluation of endovascular devices designed for the treatment of AAs.

The first rib as a fluoroscopic marker for subclavian vein access

PURPOSE

To determine whether the anatomic relationship between the subclavian vein (SCV) and the first rib is sufficiently constant to allow safe and reproducible fluoroscopically guided SCV puncture.

MATERIALS AND METHODS

Forty-four subclavian venograms were obtained from 42 consecutive adult patients. Position and width of the SCV crossing over the first rib were recorded by using radial coordinates. Based on this anatomic study, 42 SCV access procedures were performed with use of the first rib as a fluoroscopic marker. Technical success, complications, number of 21-gauge needle passes, physician experience, and patients' body habitus were recorded.

RESULTS

Mean angular position of SCV/first rib crossover was 94.7 degrees (standard deviation [SD], 7.42 degrees). Mean radial width of the SCV was 14.9 degrees (SD, 3.1 degrees). On 25 of the 44 subclavian venograms (60%), the SCV/first rib crossover lay within the 90 degrees-99 degrees segment, and on 36 of 44 (82%) it lay within the 85 degrees-104 degrees segment. Technical success in accessing the SCV was 100% (42 of 42 procedures). Two minor complications involved subclavian artery puncture with the 21-gauge needle without sequelae. The mean number of needle passes required was 2.86 (median, 1.7). There was no correlation between needle passes and patients' body habitus or physician experience.

CONCLUSION

The SCV is reliably constant in its relation to the first rib. The first rib alone provides a reliable fluoroscopic marker for safe SCV access without the need for ultrasound guidance or peripheral contrast material administration.

Transbrachial endovascular exclusion of an axillary artery pseudoaneurysm with PTFE-covered stents

PURPOSE

Endovascular exclusion of arterial injuries associated with arteriovenous fistulas and pseudoaneurysms has only recently been described using various stent-graft prostheses. This report details a transbrachial technique used to exclude an axillary artery pseudoaneurysm developing at the axillary anastomosis of an axillofemoral graft.

METHODS AND RESULTS

Thin-walled polytetrafluoroethylene was expanded with an angioplasty balloon catheter and used to cover standard Palmaz stents. Two covered stents were delivered under fluoroscopic guidance via open brachial artery access to the site, resulting in complete exclusion of the pseudoaneurysm. Follow-up duplex scanning confirmed aneurysm exclusion 3 months postprocedure.

CONCLUSIONS

This technique can be applied in arteries of different sizes and lengths, using currently available materials. However, the long-term behavior of these devices in the arterial tree must be determined before their widespread use can be recommended for most indications.

Proximal venous outflow obstruction in patients with upper extremity arteriovenous dialysis access

To evaluate the impact of central venous obstruction on upper extremity hemodialysis access failure, we retrospectively analyzed our recent experience in managing this problem. We reviewed 158 upper extremity hemodialysis access procedures performed in 122 patients during a 1-year period. Fourteen (11.5%) patients had central vein obstruction as the cause of severe arm swelling, graft thrombosis, or graft malfunction. All 14 patients had had bilateral temporary subclavian vein dialysis catheters and failed upper extremity arteriovenous access. Seventeen lesions were treated in 14 patients including eight subclavian vein occlusions, six subclavian vein stenoses, two internal jugular vein stenoses, and one superior vena cava stenosis. Twenty-one procedures were performed including 17 percutaneous transluminal balloon angioplasties (PTAs) with stent placement in 13, two axillary to innominate vein bypasses, and two axillary to internal jugular vein bypasses. All patients had resolution of symptoms. Thirteen (76%) PTAs were initially successful but in four (24%) cases it was impossible to recanalize the vein. Eight (47%) PTAs provided functional hemodialysis access for 2 to 9 months, two (12%) restenosed at 3 and 10 months and were successfully redilated, two occluded at 2 and 4 months and were unable to be recanalized, and one failed immediately after a successful PTA. Four PTA failures were followed by venous bypass, which remained patent and provided functional access 7 to 13 months after surgery. Of nine stenotic venous lesions six (67%) were successfully dilated without restenosis, whereas of eight occluded veins only two (25%) were successfully treated without recurrence. Temporary central hemodialysis catheters produce a significant number of symptomatic central vein obstructions in patients with upper extremity arteriovenous access.(ABSTRACT TRUNCATED AT 250 WORDS)

Computed tomography interpretations with a low-cost workstation: a timing study

An ergonomically simple prototype workstation with two 900 x 1,100-pixel monitors capable of displaying eight full-resolution computed tomography (CT) images in 0.2 seconds, was compared with film for interpretation of computed tomographic images of the chest and abdomen. The hardware platform for this workstation cost less than $11,500 in 1993. A repeated-measures experiment was used to generate average interpretation times of 6.17 minutes for the workstation and 6.03 minutes for the film, including loading and unloading films, with three of the four subjects averaging about a minute longer for each workstation interpretation. All dictated reports were of clinically acceptable accuracy. All radiologists stated that workstations based on this design would be an acceptable clinical tool. However, observation suggested human working-memory strain among infrequent CT readers that could indicate the need for additional training. These data suggest that low-cost workstations can have practical application in interpretation of digital medical images such as CT, with the possibility of small increases in interpretation time.

Variations in liver-colon anatomic relationship: relevance to interventional radiology

PURPOSE

To determine the prevalence of significant variations in liver-colon anatomy in an unselected patient population and evaluate the potential effect of these variations on liver-related interventional procedures.

PATIENTS AND METHODS

All abdominal computed tomographic (CT) scans were reviewed prospectively over a 4-month period. Cases that revealed variant hepatocolic anatomy were selected and analyzed for the position of the colon, gallbladder, and duodenum; liver morphology; and the anatomic relations of the right portal vein.

RESULTS

Seventeen (3.3%) of 517 abdominal CT scans demonstrated variant hepatocolic anatomic relations. In seven cases, liver lobar morphology was normal, but the colon was interposed between the chest wall and the liver. The remaining 10 cases were characterized by hypoplasia or aplasia of one or both segments of the left lobe. In these cases the right portal vein was anteriorly exposed and was close to the gallbladder and transverse colon. In all 17 cases it was qualitatively judged that technical modifications might be needed in the performance of various interventional procedures, including percutaneous biliary drainage, biopsies, and transjugular intrahepatic portosystemic shunt creation.

CONCLUSION

Variations in liver-colon anatomic relations in isolation or secondary to hepatic developmental anomalies may have a significant potential impact on the performance of various fluoroscopically guided hepatobiliary interventional procedures.

Interpretation of CT studies: single-screen workstation versus film alternator

A prototype single-screen workstation with a 2,048 x 2,560-pixel high-brightness monitor, 0.11-second image display time, and simple ergonomic design was compared to a conventional horizontal film alternator in diagnostic interpretation of chest computed tomography (CT) studies. Four radiologists used either the workstation or film alternator in interpretation of studies obtained in 10 patients. A counterbalanced within-subject repeated measures experimental design was used. Response times were analyzed for both methods of interpretation. Grades of excellent, acceptable, and unacceptable were assigned by a blinded "grader" to reports of the radiologists. The average time needed for an interpretation at the workstation was 5.65 minutes. No interpretations were graded unacceptable. Retrospective power analysis showed that 16 observers rather than four would have been required to show that use of the workstation was faster than the alternator. With this 95% confidence interval, the workstation interpretation time is clinically equivalent to that with the alternator. These data show that this type of workstation has practical application in interpretation of CT, magnetic resonance imaging, and ultrasound studies.

The spleen and its vasculature in pancreatitis: CT findings

The spleen and its vasculature are susceptible to damage from pancreatic inflammatory exudates. Fourteen patients were identified who demonstrated splenic or splenic vascular involvement from pancreatitis on computed tomography. Findings included intra- and perisplenic inflammatory fluid collections (n = 6), acute splenic hematomas (n = 3), splenic infarction (n = 1), splenic artery pseudoaneurysm (n = 1), and splenic vein thrombosis (n = 6). Eight of the 14 patients went on to urgent interventions including percutaneous catheter drainage (n = 2) and transcatheter embolotherapy (n = 6) based on the CT findings.

Radiologic placement of long-term central venous catheters: a review

The need for long-term placement of catheters within the central venous system is continually expanding and follows the increasing use of hemodialysis, total parenteral nutrition, and long-term chemotherapy for neoplastic and infectious diseases. Whereas these catheters have traditionally been placed by surgeons in an operating room, it is now clear that they can be effectively placed by interventional radiologists using percutaneous techniques within an interventional/angiographic suite. This review is based on the radiologic percutaneous placement of nearly 1,500 central venous catheters including approximately 500 tunneled Hickman/Leonard catheters, 350 double-lumen cuffed dialysis catheters, and 150 chest wall subcutaneous ports.

CT diagnosis of paraduodenal hernia

The computed tomographic (CT) findings of a right and left paraduodenal hernia are described. In the right paraduodenal hernia the major findings consist of encapsulation of small bowel loops in the right mid-abdomen with looping of arterial and venous jejunal branches behind the superior mesenteric artery. The findings of the left paraduodenal hernia are less specific and involve encapsulation of bowel loops at or above the level of the ligament of Treitz with intermittent dilatation.

Radiology-assisted placement of implantable subcutaneous infusion ports for long-term venous access

Implantable infusion port devices are generally placed surgically. A technique for radiology-guided placement in adults is described, and the experience with 103 attempted port placements between June 1989 and October 1991 is analyzed. Placements were successful in 102 attempts (99%). Minor procedural difficulties occurred in six patients (5.9%). One major procedural complication (large hematoma) precluded port placement. Two patients were lost to follow-up after uncomplicated placements. There were four (4.0% of 100 patients) minor late complications. Major late complications requiring port removal occurred in 13 (13.0%): five suspected catheter-related infections, four catheter-related venous thromboses refractory to thrombolysis, and one each of wound dehiscence, formation of hematoma near the port, extraluminal migration of the catheter, and poor blood return. With a cumulative follow-up of 15,880 days (43.5 patient-years) available, a rate of major complications of 13.6%, or 0.86% per 1,000 access days, is comparable to the rates of large surgical series. Radiology-guided placement of infusion ports is safe and may offer advantages over surgical implantation.

US guidance for vascular access. Technical note

Real-time ultrasonography (US) is frequently used to access the biliary tree, urinary system, and pleural cavity, as well as abscesses and other fluid collections, but is rarely used to access blood vessels. This article describes the clinically indicated circumstances and technical aspects of US-guided access to veins and arteries. The authors' experience suggests that appropriate use of this modality significantly simplifies vascular access difficulties, reduces procedure time and morbidity, and is cost-effective.

Percutaneous translumbar and transhepatic inferior vena caval catheters for prolonged vascular access in children

Central venous access for children with caval occlusion remains a major challenge to pediatric surgeons. Traditionally, children with superior and inferior vena cava (SVC, IVC) thrombosis have often required a thoracotomy to directly cannulate the azygos system or right atrium (RA). Recently, the possibility of placing tunneled RA catheters (RACs) by a percutaneous translumbar or transhepatic approach has become available. We report our experience of seven children with SVC and IVC obstruction who have received 11 transhepatic and 4 translumbar RACs from 1987 to 1991. All but one child was less than 2.5 years old and all were chronically dependent on parenteral nutrition. All catheters were placed in the angiography suite under general anesthesia using ultrasound guidance and Seldinger technique. This technique was successful in all seven children. Perioperative complications included accidental extubation in one patient and aspiration pneumonia in another. Mechanical complications requiring RAC replacement occurred 5 times in three infants (greater than 2,650 catheter days) and included catheter dislodgement (2) and thrombosis (3). In the patients with catheter thrombosis, the existing tract was successfully wired and the catheter exchanged on three occasions. Thrombolytic therapy was effective in restoring catheter patency on three other occassions. Nine episodes of catheter sepsis occurred in five children. Two late deaths occurred from infection. Of the five remaining children, four are dependent on total parenteral nutrition and have a translumbar or transhepatic catheter in situ and one child has adapted successfully to enteral feedings. Percutaneous translumbar or transhepatic IVC catheters provide excellent alternative routes for prolonged central venous access in those patients whose traditional vascular access sites are no longer available. Complications of the technique itself were minimal and although late catheter complications were not infrequent, they appear to be comparable to the standard approaches reported.

Intrahepatic hepatic artery aneurysm: computed tomography and color-flow Doppler ultrasound findings

An unusual case of intrahepatic hepatic artery aneurysm (IHAA) is presented, in which the diagnosis was initially suspected on computed tomography (CT) and confirmed on color-flow Doppler ultrasound (US). The literature regarding this entity, as well as the utility of color-flow Doppler US in this setting are discussed.

Case report: splenic infarction and acute splenic sequestration in adults with hemoglobin SC disease

While acute splenic sequestration and splenic infarction are commonly observed in infants and young children with sickle cell anemia, they are rarely experienced by adult hemoglobin S homozygotes because the recurrent splenic infarction that takes place during childhood is typically followed by scarring, atrophy, and splenic fibrosis. Both acute splenic sequestration and splenic infarction do remain relatively common in adults with the other sickle hemoglobinopathies. These episodes are almost certainly a consequence of the persistently enlarged and distensible spleens that often remain present in these conditions. In this report, the authors describe two adult patients with hemoglobin SC disease: one who developed acute splenic sequestration and one with splenic infarction. In neither case was there a history of recent air travel or exposure to altitude. The clinical course of these two syndromes is presented, and the hematologic, radiologic, and pathologic manifestations are discussed. Because they can sometimes be difficult to distinguish from one another, and because a failure to identify acute splenic sequestration can be catastrophic, these two entities must be included in the differential diagnosis for any hemoglobin SC patient who present with an unexplained fall in hemoglobin, left upper quadrant pain, unexplained fever, or symptomatic splenomegaly.

Transcatheter management of pseudoaneurysms complicating pancreatitis

Hemorrhage from rupture of an arterial pseudoaneurysm is a potentially fatal complication of pancreatitis. Seventeen patients underwent transcatheter embolization of 23 arteries for the treatment of 20 arterial pseudoaneurysms secondary to pancreatitis. Their records were reviewed retrospectively to evaluate the clinical benefit of transcatheter therapy. At presentation, 15 of the 17 patients had gastrointestinal, intrasplenic, retroperitoneal, intraperitoneal, or postoperative wound bleeding. Transcatheter embolotherapy was the sole treatment for 16 (80%) of the 20 pseudoaneurysms in 13 patients. Four pseudoaneurysms (20%) in four patients were treated prior to splenectomy. Transcatheter therapy was clinically beneficial in all patients. Three patients had procedural complications without significant clinical sequelae. Transcatheter embolotherapy should be the initial treatment of choice in patients with arterial pseudoaneurysms secondary to pancreatitis. Treatment may be definitive or facilitate subsequent surgery.

Evaluation of T1N0M0 lung cancer with CT

Medical records and radiologic studies of 238 patients with non-small cell lung cancer who had preoperative evaluation by chest radiography and CT were reviewed. Thirty-six patients were staged as T1N0M0 by chest radiograph. Of this group, 18 (50%) had abnormalities on CT requiring additional evaluation. Confirmation of abnormalities was by tissue sampling or clinical follow-up. Evidence for unresectable spread of disease was obtained in 12 (33%). We conclude that routine preoperative staging of T1N0M0 lung cancer with CT has a positive impact on patient management.

Amyloidosis: CT appearance of calcified, enlarged periaortic lymph nodes

The radiographic demonstration of lymph node involvement in amyloidosis is rare. We report a case of calcified, enlarged perioartic and mediastinal lymph nodes detected by CT.

Radiologic insertion of Hickman catheters in HIV-positive patients: infectious complications

Ninety-six patients undergoing radiologically guided placement of 104 Hickman catheters were grouped according to their human immunodeficiency virus (HIV) serologic status. Infectious complications were categorized according to their severity (local or systemic) and time of occurrence (periprocedural or late). The number of infectious complications per 100 indwelling catheter days was calculated. Among the 14 catheter placements in 13 HIV-positive patients, two systemic infections occurred, resulting in a 14% overall infection rate and 0.18 infectious complications per 100 indwelling catheter days. The remaining 83 HIV-negative patients underwent 90 Hickman catheter placements. Nine infectious complications (10%) were noted in the 90 catheters, translating into 0.19 infectious complications per 100 indwelling catheters days. These results suggest no significant (relative risk [RR] of 1.4 and .95) difference in infectious complication rates encountered in HIV-positive patients compared with the general population. This supports the clinical usefulness of Hickman catheter placement in HIV-positive patients, although many additional HIV-positive patients must be evaluated to achieve an acceptable level of statistical confidence.

Chronic posttraumatic aortic pseudoaneurysm. Recognition before rupture

Few patients survive transection of the aorta caused by blunt trauma. However, among those who do are a small number who go on to live with an unrecognized pseudoaneurysm that may rupture at any time. Because these aneurysms may be mistaken for more common disease processes, such as hilar adenopathy, atherosclerotic aneurysm, or neoplasia, the authors describe radiographic findings that suggest the correct diagnosis.

Antethoracic colonic esophagoplasty for esophageal atresia: long-term follow-up

We report a case of a 23-year-old woman who underwent antethoracic colonic esophagoplasty at age 3 years 10 months for failed intrathoracic correction of tracheoesophageal fistula and esophageal atresia. The appearance of this rarely performed procedure is shown with barium swallow and computed tomography.

Computed tomography of hepatic venous hypertension: the reticulated-mosaic pattern

A reticulated-mosaic pattern of the liver was identified on contrast-enhanced computed tomography in 4 of 20 patients with constrictive pericarditis or congestive heart failure. Reflux of contrast into a distended inferior vena cava and the hepatic veins was identified in 3 of the 4 patients. This abnormal enhancement pattern combined with hepatic venous or caval reflux of contrast indicates the presence of hepatic venous hypertension, and should not be mistaken for other abnormalities that may result in inhomogeneous hepatic enhancement.