New CT index to quantify arterial obstruction in pulmonary embolism: comparison with angiographic index and echocardiography

OBJECTIVE

This study was designed to define and evaluate a specific index to quantify arterial obstruction with helical CT in acute pulmonary embolism.

MATERIALS AND METHODS

Fifty-four patients (mean age, 56 years) with proven pulmonary emboli among 158 consecutive patients, who had undergone both CT and pulmonary angiography for clinically suspected pulmonary embolism, were eligible for the study. The CT obstruction index was defined as (n. d) (n, value of the proximal clot site, equal to the number of segmental branches arising distally; d, degree of obstruction scored as partial obstruction [value of 1] or total obstruction [value of 2]). We compared the CT obstruction index with pulmonary arterial obstruction on angiography (assessed by the Miller index), using linear regression, and correlated it with findings on echocardiography. Interobserver variability was determined for both CT and pulmonary angiography indexes.

RESULTS

The CT obstruction index (29% +/- 17%) and the Miller index (43% +/- 25%) were well correlated (r = 0.867, p < 0.0001) with an excellent concordance between investigators for both the CT index (r = 0.944, p < 0.0001) and the Miller index (r = 0.904, p < 0.0001). A CT obstruction index greater than 40% identified more than 90% of patients with right ventricular dilatation.

CONCLUSION

The degree of arterial obstruction in pulmonary embolism may be quantified by a specific CT index that appears reproducible and highly correlated to the previously described index with pulmonary angiography. Further evaluations are needed to investigate the usefulness of the CT obstruction index for stratification of patient risk and determining therapeutic options.

Pulmonary embolism detection: prospective evaluation of dual-section helical CT versus selective pulmonary arteriography in 157 patients

PURPOSE

To evaluate the accuracy of dual-section helical computed tomography (CT) in acute pulmonary embolism (PE) diagnosis.

MATERIALS AND METHODS

Of 204 consecutive patients with clinically suspected acute PE (mean age, 58 years +/- 14 [SD]), 158 were enrolled. All patients underwent dual-section helical CT (2.7-mm effective section thickness) and selective pulmonary arteriography within 12 hours of each other. Each image was analyzed independently by two observers, who determined image quality and presence of PE among arterial segments, including at the subsegmental level. The final diagnosis was made with consensus.

RESULTS

Selective pulmonary arteriography was considered optimal in 147 (93%), suboptimal in 10 (6%), and inconclusive in one (0.6%) of 158 patients. Dual-section helical CT findings were considered technically optimal in 140 (89%), suboptimal in 11 (7%), and inconclusive in six (4%). Selective pulmonary arteriography demonstrated PE in 62 patients. Four (6%) of 62 patients had isolated subsegmental PE. The sensitivity of dual-section helical CT was 90%, and the specificity was 94%. The positive and negative predictive values were 90% and 94%, respectively.

CONCLUSION

Dual-section helical CT is an improvement in helical CT that offers a high sensitivity and specificity for the depiction of PE, including at the subsegmental level. Dual-section helical CT can replace pulmonary arteriography for the direct demonstration of PE in a majority of patients.

Abdominal aortic aneurysm: pretherapy assessment with dual-slice helical CT angiography

OBJECTIVE

The purpose of this study was to evaluate dual-slice helical CT in the pretherapy assessment of abdominal aortic aneurysms.

SUBJECTS AND METHODS

Dual-slice helical CT angiography was performed in 47 consecutive patients (mean age, 59 years) with abdominal aortic aneurysm to determine whether we could then evaluate the extent of aneurysm and see associated renal, celiac, mesenteric, and iliofemoral artery disease. Results were compared with those of digital subtraction angiography (n = 47) and surgery (n = 37).

RESULTS

The proximal and distal extents of abdominal aortic aneurysm correlated well with surgical findings. Dual-slice helical CT showed all main (n = 102) and accessory (n = 13) renal arteries with a sensitivity of 91% and a specificity of 100% for revealing associated renal artery stenosis exceeding 50%. Sensitivity and specificity of dual-slice helical CT for revealing stenosis exceeding 75% in celiac and superior mesenteric arteries were both 100%. Three of four iliofemoral artery stenoses and two occlusions of the common iliac artery were revealed by dual-slice helical CT.

CONCLUSION

Helical CT angiography with dual-slice scanning is a useful and minimally invasive technique that can provide with high accuracy all the necessary information for treatment of abdominal aortic aneurysm.

[Late solitary metastasis of a renal cancer to the contralateral adrenal gland]

We report a case of metachronous metastasis from renal cell carcinoma to the contralateral adrenal gland detected one year after radical nephrectomy. The initial tumor was incidentally discovered in the setting of acute aortic dissection. A large left adrenal tumor was detected on CT follow-up at two years. Retrospectively, a hypervascular lesion was present on the first yearly CT examination. Adrenalectomy was performed. There is no evidence of recurrent disease at 12 months. The patient was also treated with oral steroids. Because of their location and of the particularities of available therapeutic options, and because these metastases can occur late, long-term sonographic and CT follow-up should be performed. The clinical, imaging, therapeutic and prognostic aspects of these lesions will be discussed.

[Arterial lipiodol chemoembolization of a left liver metastasis through the right internal thoracic artery]

The purpose of this article is to illustrate the efficacy of the chemoembolization in patients with hypervascular metastases and to describe the post-embolization change in vascularization pattern. Unusual collaterals may develop following embolization. A 59-year-old woman, followed for unresectable small bowel carcinoid tumor since 1991, underwent successful chemoembolization of several liver metastases. Only one liver lesion, located in segment IV, showed interval increase in size. This lesion was supplied by the right internal mammary artery. A branch of the right internal mammary artery was catheterized using a microcatheter and embolization was performed using doxorubicine-Lipiodol (Adriblastine, Lipiodol) and gelfoam (Spongel). No complications occurred after the procedure. The right internal mammary artery should be considered as a possible source of collateral arterial supply to the liver and should be evaluated in patients with local progression of disease.

Percutaneous gastrostomy for enteral nutrition: long-term follow-up of 176 procedures

OBJECTIVE

To evaluate the efficacy and safety of percutaneous gastrostomy (PG), using small catheters without gastropexy, to deliver enteral nutrition.

METHODS

We reviewed the records of 176 consecutive patients in whom PG was attempted for enteral nutrition. Of these cases, 172 catheters were inserted by the Seldinger technique under fluoroscopic guidance alone, 2 were inserted under computed tomographic guidance, and 2 procedures failed. In primary procedures, 8.5- or 10.2-French catheters were used.

RESULTS

The technical success rate was 98.9%. Of the 176 procedures, 2 failed because of the high position of the stomach. Seven-day follow-up was obtained in all patients; 30-day follow-up in 145 patients (83%), and long-term follow-up (30 to 1512 days) in 123 patients (70%). The 30-day mortality rate was 13.2%. One death (0.5%) was directly related to the procedure. Major complications occurred in 4 patients (2.2%), and minor complications in 12 patients (6.9%). No patient required surgery for complications attributable to the gastrostomy procedure.

CONCLUSION

PG without gastropexy using small catheters is a simple, safe and effective technique for delivering enteral nutrition.

Subacute and chronic benign superior vena cava obstructions: endovascular treatment with self-expanding metallic stents

OBJECTIVE

Our purpose is to report our clinical experience with patients who underwent endovascular treatment with Wallstents for subacute or chronic benign obstruction of the superior vena cava (SVC).

SUBJECTS AND METHODS

Twelve patients who were an average of 54 +/- 12 years old were referred for treatment of severe SVC syndrome related to implanted central venous catheters (n = 8), postradiation fibrosis (n = 2), a permanent pacemaker (n = 1), or a benign tumor (n = 1). Symptoms were present for an average of 16 weeks (range, 4-48 weeks) before treatment. Diagnosis of SVC obstruction was confirmed with helical CT and pretherapeutic phlebography. Four patients had Stanford's type II stenosis; two, type III; and six, type IV. The mean clinical and radiologic follow-up intervals were 11 months (range, 1-36 months) and 7 months (range, 1 week to 32 months), respectively.

RESULTS

Recanalization was successful in all patients. Fifteen stents were implanted in the 12 patients. Stents were placed after percutaneous balloon angioplasty in nine patients, and primary stent placement was attempted in three patients. We immediately achieved a satisfactory SVC diameter in all patients, whose symptoms were relieved completely within 1 week of stent placement. No technical or clinical complications occurred. SVC syndrome recurred in one patient 2 months after stent placement and was treated by placing a second stent.

CONCLUSION

Endovascular treatment with stent placement should be considered relevant and safe for refractory benign SVC syndrome. However, a larger series and a longer follow-up period are needed to define the role of stent placement for this syndrome.

Helical CT phlebography of the superior vena cava: diagnosis and evaluation of venous obstruction

OBJECTIVE

The purpose of this study was to determine the feasibility of helical CT phlebography of the superior vena cava (SVC) and to evaluate the role of this imaging technique in the diagnosis and treatment of SVC obstruction.

SUBJECTS AND METHODS

Twenty-three helical CT phlebograms were obtained of patients with clinical findings that were suggestive of SVC obstruction (n = 19) and of patients undergoing posttherapeutic evaluation for SVC obstruction (n = 4). CT examinations consisted of helical acquisitions obtained in the craniocaudal direction with simultaneous bilateral antecubital vein injection of 2 x 90 ml of 12% iodinated contrast material at 2 ml/sec. Combined analysis of axial, multiplanar, and maximum-intensity-projection reformatted images was used for all patients. Image quality, venous stenosis or obstruction, intraluminal thrombus, and collateral pathways were evaluated. Comparison with digital phlebographic data was available for 16 patients; this comparison was performed in a nonblinded manner.

RESULTS

CT phlebograms were considered technically optimal in 91% of the patients. In all these patients, helical CT phlebograms showed the venous obstruction: the site, extent, cause, and collateral pathways. CT phlebography appeared to be well correlated with digital phlebography in 16 patients regarding the degree of obstruction, the presence of collateral pathways, and the presence of thrombus.

CONCLUSION

Helical CT phlebography may be a useful technique for imaging the SVC and its tributaries. This imaging technique is simple to perform and can provide all the information necessary to diagnose and treat SVC obstruction.

[Preoperative angiographic landmarks of the gluteal muscle regions using Patent Blue V]

Use of a gluteus musculocutaneous flap is the most reliable technique for surgical repair of sacral ulcers. Surgery could be ideally performed when the flap is designed using only the upper or the lower half of the glutens maximus muscle depending on the superior gluteal artery or the inferior gluteal artery, respectively. The authors have developed a technique for preoperative demonstration of the vascular supply to both muscle and overlying skin from a single gluteal artery using superselective catheterization and arterial administration of a dye (Patent Blue V). This technique facilitates the surgical procedure but assessment of its usefulness will require further evaluation.

[Positional occlusion of the descending scapular artery in transverse thoraco-brachial syndrome with neurologic symptoms]

We report a thoracic outlet syndrome revealed by neurological complications. Angiography of the subclavian artery depicted an isolated positional occlusion of the descending scapular artery. This side branch of the subclavian artery is anatomically located close to and supplies the brachial plexus. Surgical treatment led to improvement of most symptoms and post-operative control angiography was normal. Not previously described, this sign illustrates the objective compression of the brachial plexus. Ischemia is perhaps intricated with compression, a well-known pathophysiological mechanism of neurological complications in this syndrome. This artery feeding the brachial plexus is usually ligated during surgical neurolysis but must be preserved in order to improve recovery of neurological function and prevent surgical failures.

The comet-tail artifact. An ultrasound sign of alveolar-interstitial syndrome

Can ultrasound be of any help in the diagnosis of alveolar-interstitial syndrome? In a prospective study, we examined 250 consecutive patients in a medical intensive care unit: 121 patients with radiologic alveolar-interstitial syndrome (disseminated to the whole lung, n = 92; localized, n = 29) and 129 patients without radiologic evidence of alveolar-interstitial syndrome. The antero-lateral chest wall was examined using ultrasound. The ultrasonic feature of multiple comet-tail artifacts fanning out from the lung surface was investigated. This pattern was present all over the lung surface in 86 of 92 patients with diffuse alveolar-interstitial syndrome (sensitivity of 93.4%). It was absent or confined to the last lateral intercostal space in 120 of 129 patients with normal chest X-ray (specificity of 93.0%). Tomodensitometric correlations showed that the thickened sub-pleural interlobular septa, as well as ground-glass areas, two lesions present in acute pulmonary edema, were associated with the presence of the comet-tail artifact. In conclusion, presence of the comet-tail artifact allowed diagnosis of alveolar-interstitial syndrome.

Percutaneous recanalization of a renal artery in aortic dissection

Chronic renal failure acutely worsened in a patient with a type B aortic dissection. Aortography revealed an occlusion of the left renal artery without renal intimal tear. Percutaneous recanalization, performed with a self-expandable stent, resulted in improvement in the renal function. This technique offers a new therapeutic choice in patients with visceral complications of aortic dissection.