Janis Gissel Letourneau

Use of gianturco self-expandable stents in the tracheobronchial tree

Gianturco self-expandable stents were used successfully in the management of 5 patients with tracheobronchial pathology. Placement was performed under endoscopic and fluoroscopic guidance. None of the patients has experienced complications secondary to the stent placement, and in all of them the clinical problems resolved satisfactorily. Longer follow-up is required to determine the place of tracheobronchial stenting in patients with respiratory compromise.

Transplant Renal Artery Stenosis: Evaluation with Duplex Sonography

Determination of the cause of hypertension in renal transplant recipients has required invasive studies such as angiography. Consequently there has been recent interest in noninvasive evaluation. Over a 19-month period, duplex sonography was performed on the renal transplant vasculature in 31 allograft recipients who also underwent correlative arteriography. One patient underwent a repeat duplex study and arteriography after surgical repair. On the basis that a frequency shift greater than 7.5 kHz and associated distal turbulence indicate stenosis, 18 duplex sonographic studies were considered positive. Subsequent angiography showed renal artery stenosis in 16 patients and no significant lesion in two. In 14 patients Doppler studies were interpreted as normal; angiography showed no significant arterial abnormality in 13 and significant stenosis in one. These results indicate a sensitivity of 94.1% and specificity of 86.7% for duplex sonography in the diagnosis of transplant renal artery stenosis. Duplex sonography appears to be an excellent noninvasive screening method to evaluate arterial stenosis following renal transplantation.

The role of radiology in the diagnosis and treatment of biliary complications after liver transplantation

Hepatic transplantation is now an accepted therapeutic option for selected patients with terminal liver disease. Biliary complications are, however relatively common after transplantation. We reviewed our experience with diagnostic and therapeutic biliary radiologic procedures in 151 hepatic recipients. Biliary complications were seen in 25% of patients. Interventional radiologic procedures were an integral part of the diagnostic and therapeutic management of these patients; reoperation was, nonetheless, occasionally required.

CT findings in left paraduodenal herniae

Computed tomography (CT) was used to evaluate mass effect on the greater curvature of the stomach in two children with histories of intermittent, recurrent vomiting. The paraduodenal herniae were identified on CT in both of these patients as small bowel interposed between the stomach and the body of the pancreas.

Early sonographic evaluation of the transjugular intrahepatic portosystemic shunt (TIPS)

The purpose of this study was to evaluate duplex and color Doppler findings in patients before and within 24 h after transjugular intrahepatic porto-systemic shunts (TIPS). Conventional duplex and color Doppler were used in the assessment of 19 patients who underwent TIPS as part of a prospective protocol. Patients were examined within 24 h before and after the procedure. Before TIPS, patency, flow direction, and peak flow velocity in the main portal vein and hepatic artery were studied, as well as patency and flow direction in hepatic veins, splenic vein, and inferior vena cava (IVC). Immediately after the procedure, sonographic identification of stent position, shunt patency, and flow dynamics were evaluated and patency and flow direction of hepatic veins, splenic vein, and IVC were determined. The portogram performed at the end of the procedure was compared with the 24-h sonographic studies after TIPS to determined sonographic/angiographic correlation. No intraparenchymal abnormalities or perihepatic fluid collections were detected after the procedure. The metallic stent was clearly seen in all patients. Mean peak shunt flow velocities were 139±50 cm/sec within 24 h after TIPS. Absence of flow through the shunt was correctly identified in one case and confirmed angiographically. Mean peak flow velocity in the portal vein before TIPS was 22±13.6 cm/sec and increased to 43.6±9.1 cm/sec after TIPS (p<0.05). The hepatic artery peak systolic velocity increased from 77±51 cm/sec before TIPS to 119±53 cm/sec after the procedure (p=0.029). Conventional duplex and color Doppler ultrasound proved to be a useful non-invasive diagnostic method to assess patients who have undergone TIPS. We propose its use as the primary diagnostic modality in these patients.

Angiogenesis after Hepatic Arterial Occlusion in Liver Transplant Patients

The authors describe 10 liver transplant recipients who developed occlusion of the hepatic artery or aortic conduit. Since all potential collateral arterial supply to the transplant is severed at hepatectomy, hepatic artery occlusion is usually a catastrophic event that necessitates repeat transplantation. Four patients died within 8 weeks of transplantation. The remaining six developed spontaneous arterial liver revascularization. This phenomenon is believed to be an example of neovascularization through angiogenesis. Radiologic studies, particularly duplex sonography and angiography, were helpful in the evaluation of transplant vascular integrity. The tissues of the omentum and the mesentery have known angiogenic ability. The authors postulate that in transplantation techniques in which these tissues are placed close to the transplanted liver (eg, Roux-en-Y choledochojejunostomy), the omental and mesenteric tissues may be the source of neovascularity.

Endothelium-dependent vasodilation of peripheral conduit arteries in patients with heart failure

Endothelium-dependent vasodilation of peripheral resistance vessels is abnormal in patients with heart failure, but there are little in vivo data on endothelium-dependent vasodilation of peripheral conduit vessels. This study assessed endothelium-dependent vasodilation of forearm conduit and resistance vessels in normal subjects and patients with heart failure. The effects of intraarterial endothelium-dependent and endothelium-independent vasodilators on both forearm conduit (brachial artery) and resistance vessels were assessed in 9 patients with New York Heart Association class II-III heart failure and 11 normal subjects of similar age. Brachial artery diameter was measured by two-dimensional, moderate-frequency (8 MHz) ultrasound, and forearm blood flow was measured by strain gauge plethysmography. The endothelium-dependent vasodilator, methacholine (0.3 and 1.5 micrograms/min), increased brachial artery diameter by 7.6 +/- 1.3% and 12.2 +/- 1.5% in normal subjects as compared to 6.9 +/- 2.1% and 10.4 +/- 2.4% in patients with heart failure (P = NS, normal vs heart failure). The endothelium-independent vasodilator, nitroglycerin (0.15 microgram), also produced similar increases in brachial artery diameter in the two groups (8.2 +/- 1.3% in normal subjects vs 11.1 +/- 1.4% in patients with heart failure, P = NS). In contrast, forearm blood flow responses to methacholine were significantly (P < .05) greater in normal subjects (4.1 +/- 0.5 and 9.2 +/- 1.4 mL/min/100 mL forearm volume) than in patients with heart failure (2.0 +/- 0.8 and 5.1 +/- 1.3 mL/min/100 mL forearm volume). Forearm blood flow responses to the endothelium-independent vasodilator, sodium nitroprusside, were similar between the two groups. This study suggests that endothelium-dependent and endothelium-independent vasodilation of the brachial artery is not impaired in patients with class II-III heart failure. This finding contrasts with abnormal endothelium-dependent vasodilation of forearm resistance vessels. These data suggest that there are regional differences in endothelial function in patients with heart failure.

Chest-wall deformity after tissue expansion for breast reconstruction

A prospective longitudinal study of chest-wall deformity after tissue expansion for breast reconstruction was performed in 19 women. CT imaging was a sensitive method for detecting occult deformity. Using a semiquantitative scale for measuring deformity, all patients and 94 percent of expanders had some thoracic abnormality after tissue expansion. Rib and chest-wall contour changes were observed under 81 and 68 percent of the expanders, respectively. Routine chest roentgenograms were not a sensitive method for evaluating these deformities. The magnitude of deformity after unilateral expansion was not significantly different from that after bilateral expansion. Linear regression analysis indicated that early periprosthetic capsular contracture was negatively correlated with chest wall deformity. Only one patient experienced a clinically noticeable complication from chest compression--transient postexpansion exertional dyspnea. After removing the expanders and placing permanent implants along with capsulotomy, the mean deformity index decreased by 57 percent after 10.5 months median follow-up, which was highly significant (p less than 0.001). Our findings suggest that chest-wall deformity is a common occurrence after tissue expansion in patients undergoing breast reconstruction and is usually of minor clinical significance.

CT appearance of antibiotic-induced colitis

Eleven abdominal computed tomographic (CT) examinations were performed in 10 patients with antibiotic-induced colitis. The clinical, endoscopic, and CT findings are presented. The most common CT findings were colonic dilatation and bowel wall thickening. However, small bowel dilatation was commonly seen. Intramural gas and ascites were less frequent findings. The diagnosis of antibiotic-induced colitis was rarely made before CT examination. Consequently, attentiveness to these CT abnormalities can expedite specific treatment. When these findings are noted on CT they represent the equivalent of toxic megacolon and administration of rectal contrast is contraindicated.

Effects of Central Venous Catheter Placement on Upper Extremity Duplex US Findings

PURPOSE The upper extremity veins of 17 patients who underwent operative central venous catheter placement were studied prospectively with color duplex sonography to determine which duplex changes, if any, could be due to the presence of the catheter alone and to determine if these waveform changes could mimic the dampened waveform seen peripheral to central nonvisualized or nonocclusive thrombosis or proximal stenosis. PATIENTS AND METHODS The subclavian, internal jugular, and brachiocephalic veins were examined with color duplex sonography immediately before and after catheter placement. Images obtained before and after catheterization were reviewed by two radiologists for (a) spectral broadening in both the vein of insertion and the brachiocephalic vein, (b) transmission of atrial pulsations, and (c) respiratory phasicity. RESULTS In all cases, atrial pulsatility and respiratory phasicity were present before and after catheter placement. There was no statistically significant change in the amount of spectral broadening after catheter placement. A mild increase in the peak blood flow velocity of 7 cm/sec (P = .04) in the ipsilateral brachiocephalic vein was demonstrated; however, no significant increase in velocity could be shown in the vein of insertion. CONCLUSION In this clinical setting, the hemodynamic changes within the vein from the catheter placement are minimal. Any damping of the venous waveform seen with sonography performed to rule out upper extremity deep venous thrombosis secondary to indwelling catheter--for example, loss of atrial pulsatility or respiratory phasicity--is presumably due to the presence of venous thrombosis or stenosis.