Our Experience on Light Reflection Rheography (LRR): A New Non-Invasive Method for Lower Limbs Venous Examination

By means of a light reflection rheograph (LRR 100), the authors studied 353 lower limbs: 128 with primary varices, 41 with a post-phlebitic syndrome and 81 controls. The parameters that were selected were: VRT (venous refill time) and ΔLR (as expression of the venous emptying rate). In order to assess the accuracy of LRR measurements, simultaneous recordings of both LRR and venous pressure changes in 97 limbs (58 with primary varicose disease, 21 with post-phlebitic syndrome and 18 normals) were compared with each other. The correlation rate for VRT in the two methods revealed very high agreement, (r = 0.96). A fairly good correlation also occurred between changes in venous pressure and ΔLR (r = 0.74). The reproducibility rates ranged between ± 15.9% s.d. (VRT) and ± 7.7% s.d. (ΔLR), using 100 as the average value obtained from each subject.

The authors conclude that LRR appears to offer high specificity, sensitivity and reproducibility rates for non-invasive assessment of valvular incompetence. It appears also potentially reliable for the evaluation of calf musculo-venous pump efficiency.

Comparison of carotid artery blood velocity measurements by vector and standard Doppler approaches

Although severely affected by the angle dependency, carotid artery peak systolic velocity measurements are widely used for assessment of stenosis. In this study, blood peak systolic velocities in the common and internal carotid arteries of both healthy volunteers and patients with internal carotid artery stenosis were measured by two vector Doppler (VD) methods and compared with measurements obtained with the conventional spectral Doppler approach. Although the two VD techniques were completely different (using the transmission of focused beams and plane waves, respectively), the measurement results indicate that these techniques are nearly equivalent. The peak systolic velocities measured in 22 healthy common carotid arteries by the two VD techniques were very close (according to Bland-Altman analysis, the average difference was 3.2%, with limits of agreement of ± 8.6%). Application of Bland-Altman analysis to comparison of either VD technique with the spectral Doppler method provided a 21%-25% average difference with ± 13%-15% limits of agreement. Analysis of the results obtained from 15 internal carotid arteries led to similar conclusions, indicating significant overestimation of peak systolic velocity with the spectral Doppler method. Inter- and intra-operator repeatability measurements performed in a group of 8 healthy volunteers provided equivalent results for all of the methods (coefficients of variability in the range 2.7%-6.9%), even though the sonographers were not familiar with the VD methods. The results of this study suggest that the introduction of vector Doppler methods in commercial machines may finally be considered mature and capable of overcoming the angle-dependent overestimation typical of the standard spectral Doppler approach.

Differences between internal jugular vein and vertebral vein flow examined in real time with the use of multigate ultrasound color Doppler

BACKGROUND AND PURPOSE

The hypothesis that MS could be provoked by a derangement of the blood outflow from the brain has been largely discredited. In part, it was because data on the normal pattern of outflow are scarce and obtained with different methods. The aim of this study was to evaluate the normal pattern of outflow for the vertebral and internal jugular veins in healthy subjects with multigate color Doppler.

MATERIALS AND METHODS

Twenty-five volunteers were studied to assess vessel area, mean velocity, and flow for the vertebral and internal jugular veins in the supine and sitting positions.

RESULTS

In the sitting position, flow decreases, both in vertebral veins and internal jugular veins, as the total vessel area decreases (from 0.46 ± 0.57 to 0.09 ± 0.08 cm(2)), even if the mean velocity increases (from 12.58 ± 10.19 to 24.14 ± 17.60 cm/s). Contrary to what happens to the blood inflow, outflow in the supine position, through vertebral and internal jugular veins, is more than twice the outflow in the sitting position (739.80 ± 326.32 versus 278.24 ± 207.94 mL/min). In the sitting position, on application of very low pressure to the skin with the sonography probe, internal jugular veins rarely appear to occlude. A pronounced difference of diameter between internal jugular veins was present in approximately one-third of subjects.

CONCLUSIONS

Our results support the view that other outflow pathways, like the vertebral plexus, play a major role in the normal physiology of brain circulation and must be assessed to obtain a complete picture of blood outflow.

[Color Doppler evaluation and diagnosis of local complications after arterial endovascular procedures]

Diagnostic and therapeutic percutaneous endovascular procedures have become more and more common in recent years, and so also the number of local complications has increased. After such procedures a simple clinical examination may show the presence of an inguinal mass, but does not permit a diagnosis, while Color Doppler and Duplex Scanner can make a differential diagnosis between hematoma, pseudoaneurysm, arteriovenous fistula or other disease. Color Doppler is ubiquitously used to diagnose such complications as it offers a low-cost, easy-to-use method, only minimally uncomfortable for the patient. This ultrasound system can provide both anatomic and haemodynamic information. Our study highlights the diagnostic possibilities offered by the Color Doppler and Duplex Scanner and details, using many illustrations and examples, how the most common complications such as hematoma, pseudoaneurysm, arteriovenous fistula and thrombosis are imaged. Hematoma appears as a hypoechogenic zone, with no color inside, as flow is not present. Pseudoaneurysms, unlike hematoma, maintain a connection with an injured blood vessel, and so they show blood flow both inside the lesion and in the communicating channel, with a typical pattern. The arteriovenous fistula is a vascular channel created, after a percutaneous procedure, between an artery and an adjacent vein that have both been damaged. An endovascular thrombus is directly shown as a luminal defect of flow. Other less common complications are discussed and illustrated.

Interventional radiology in the treatment of early postoperative biliary complications

PURPOSE

We sought to evaluate the feasibility and efficacy of percutaneous treatment of early postoperative biliary complications. The primary aims were to evaluate clinical and technical success and complications and perioperative mortality, and secondary aims were to evaluate treatment duration and recurrence rate.

MATERIALS AND METHODS

Between March 2007 and March 2010, 75 patients (42 men and 33 women; age range, 17-88 years; mean age, 60.8 years) underwent interventional radiology procedures to treat early postoperative biliary complications of biliary and pancreatic-duodenal surgery with biliodigestive anastomosis (37.7%), laparoscopic cholecystectomy (30.6%), hepatic resection (21.1%) and several other surgical procedures (10.6%). Complications included fistulas (73%), stenoses (20%) and complete bile duct transections (7%).

RESULTS

Interventional radiology achieved complete clinical success in 74 cases (85.9%) and in particular in 95.2% of fistulas, 76.5% of stenoses and 33.3% of complete bile duct transections. Mean indwelling catheter time was 34.9 days, with an average of 4.1 procedures. There were two cases of severe haemobilia (2.3%). Minor complications occurred in 7% of cases. Perioperative mortality rate was 1.2% and overall recurrence rate 6.7% (range, 1-18 months; mean, 10 months), with recurrences occurring predominantly in stenoses. All patients were retreated successfully.

CONCLUSIONS

Percutaneous procedures are feasible, effective and safe for treating early postoperative biliary complications. They provide a valuable alternative to presendoscopy, which is precluded in many of these patients, and to surgery, which has higher morbidity and mortality rates.

Ultrasound-guided transhepatic puncture of the hepatic veins for TIPS placement

PURPOSE

This retrospective analysis was carried out to assess the feasibility and results of transjugular intrahepatic portal systemic shunt (TIPS) performed with ultrasound (US)-guided percutaneous puncture of the hepatic veins.

MATERIAL AND METHODS

Over a period of 3 years, 153 patients were treated with TIPS at our centre. In eight cases, a percutaneous puncture of the middle (n=7) or right (n=1) hepatic vein was required because the hepatic vein ostium was not accessible. Indications for TIPS were bleeding (n=1), Budd-Chiari syndrome (n=1), ascites (n=2), reduced portal flow (n=1) and incomplete portal thrombosis (n=3). A 0.018-in. guidewire was anterogradely introduced into the hepatic vein to the inferior vena cava (IVC) through a 21-gauge needle. In the meantime, a 25-mm snare-loop catheter was introduced through the jugular access to retrieve the guidewire, achieving through-andthrough access. Then, a Rosch-Uchida set was used to place the TIPS with the traditional technique.

RESULTS

Technical success was achieved in all patients. There was one case of stent thrombosis. One patient died of pulmonary oedema. Three patients were eligible for liver transplantation, whereas the others were excluded due to shunt thrombosis (n=1) and previous nonhepatic neoplasms (n=3).

CONCLUSIONS

The percutaneous approach to hepatic veins is rapid and safe and may be useful for avoiding traumatic liver injuries.

Fifteen years' experience with transjugular intrahepatic portosystemic shunt (TIPS) using bare stents: retrospective review of clinical and technical aspects

PURPOSE

The authors present a retrospective analysis of a large series of patients who underwent transjugular intrahepatic portosystemic shunt (TIPS) placement.

MATERIALS AND METHODS

Between March 1992 and December 2006, 658 patients were referred to our centre for TIPS placement. Indications for the procedure were digestive tract bleeding (52.8%), refractory ascites (35.3%), preservation of portal vein patency prior to liver transplantation (3.0%) and thrombosis of the suprahepatic veins (2.3%). Other indications (6.6%) included pleural ascites, portal thrombosis and hepatorenal and hepatopulmonary syndromes. All patients were evaluated with colour Doppler ultrasonography and in a few cases with computed tomography. The portal system was punctured under sonographic guidance. Wallstent, Palmaz and Nitinol thermosensitive stents were used. Embolisation of persistent varices was performed in 6.8% of cases.

RESULTS

Technical success was 98.9%. During a 1,500-day follow-up, the cumulative incidence of stent revision was 25.7% (Nitinol), 32.9% (Wallstent) and 1.8% (Palmaz). Mortality rates were 31.1%, 38.5% and 56.4%, respectively. The technical complications included six cases of heart failure, six of haematobilia, three of stent migration, two of intrahepatic haematoma and one of haemoperitoneum. Eight patients with severe portosystemic encephalopathy (PSE) were treated with a reduction stent.

CONCLUSIONS

TIPS placement is safe and effective and may act as a bridge to liver transplantation. Ultrasonography plays a fundamental role in the preliminary assessment, in portal vein puncture and during the follow-up. Stent patency is satisfactory.

The radiologist's role in managing paediatric liver transplantation: personal experience with 40 patients

PURPOSE

The aim of our study was to evaluate the radiologist's role in managing paediatric orthotopic liver transplantation (OLT) through a retrospective review of our experience in diagnosing and treating post-OLT complications.

MATERIALS AND METHODS

Forty children (mean age 4.6 years) underwent 44 OLTs over 71 months. The follow-up period (mean 724 days) was divided into three phases: hospital stay, up to three months after discharge and subsequent period. The number and type of radiological examinations, radiologically detectable complications and interventional procedures were analysed.

RESULTS

Most examinations were carried out with ultrasound (US) (859/931 of all radiological studies performed during the first two phases, 92.3%). Colour-Doppler US enabled early detection and treatment of all vascular complications (9/40, 22.5% of patients; 13 complications in nine patients, eight arterial and five portal complications; 1.4 for each patient with complications). Computed tomography (CT) or angiography was very rarely employed. US also detected biliary complications (11 patients, 27.5%: three cases of segmental ducts excluded from the anastomosis, four cases of stenosis of the biliodigestive anastomosis, one lithiasis, three stenoses associated with lithiasis), which were successfully managed in 75% of the cases treated with interventional radiology procedures (percutaneous bilioplasty and/or lithotripsy). At the time of writing this paper, the patient survival rate was 100%, and the organ survival rate was 91% (40/44). There were four re-transplantations: three due to hepatic artery thrombosis and one to biliary stenosis with lithiasis.

CONCLUSIONS

The radiologist's role is fundamental for early sonographic diagnosis of post-OLT complications in children. Vascular complications are often associated in a single patient, and early treatment may improve the prognosis. Interventional radiology represents a safe and effective treatment for many biliary complications.

Femoral haemostosis with Vasoseal ES: experience in 150 patients

PURPOSE

The aim of this study is to assess the effectiveness and safety of the use of Vasoseal ES collagen plug in heavily anticoagulated patients with high risk of complications at the vascular access site who had undergone vascular radiological intervention.

MATERIALS AND METHODS

Between January 2002 and March 2003 180 consecutive transfemoral arterial accesses in 169 patients subjected to vascular radiological procedures were performed (bilateral access was performed in 11 patients): 140 percutaneous transluminal angioplasties and 40 transarterial chemoembolisations. All the patients who underwent angioplasty were given 3,000 IU of sodic heparin intravenously during the procedure and later a prolonged antiaggregant therapy was undertaken (ticlopidine 500 mg/day and aspirin 150 mg/day). The sheaths were removed at the end of the surgical manoeuvre and two cartridges of collagen were positioned on the external surface of the artery. The mean values of platelets and partial thromboplastin time were 42,000/ml and 170 s, respectively, in cirrhotic patients against 250,000/ml and 200 s in patients with peripheral arteriopathy. The next day a colour Doppler examination was performed at the puncture site.

RESULTS

The technique proved successful in 89.4% of cases (161/180). In 19/180 vascular accesses placement of the haemostatic cartridges was not possible owing to the inability to compress the common femoral artery proximal to the release site (4/19), owing to a pre-existing haematoma (5/19) and owing to the limited presence of subcutaneous tissue (10/19). The mean time required for the placement of Vasoseal ES was 4 min. The mean time-to-haemostasis was 6 min. The mean time-to-mobilisation was 4 hr. Only in two patients was there an onset of a pseudoaneurysm of the right common femoral artery; the lesions were treated with ultrasonography -guided compression. In addition, 16 small local haematomas were recorded. In 4 cases early re-puncture of the femoral artery was performed (24-48 hr following the use of the device) without consequences.

CONCLUSIONS

Vasoseal ES is a safe collagen closure device characterised by a high success rate. In anticoagulated patients the device can reduce the time-to-mobilisation and the incidence of complications.

Percutaneous radiological gastrostomy: a safe and effective method of nutritional tube placement in advanced ALS

BACKGROUND

Enteral nutrition may be required in amyotrophic lateral sclerosis (ALS), and is usually achieved by percutaneous endoscopic gastrostomy (PEG). As PEG is not indicated in patients with severe respiratory impairment, an alternative is percutaneous radiological gastrostomy (PRG), involving air insufflation into the stomach under fluoroscopic guidance for tube insertion.

OBJECTIVE

To evaluate the safety of PRG and its effect on survival and respiratory function in ALS patients with respiratory failure.

METHODS

25 consecutive ALS patients with severe dysphagia and forced vital capacity (FVC) <50% underwent PRG after October 2000. They were compared with 25 consecutive ALS patients with FVC <50% who underwent PEG before October 2000. Respiratory function was evaluated before and after the procedure.

RESULTS

The two groups were similar for all relevant characteristics. PRG was successful in all cases, PEG in 23/25. One patient in each group died after the procedure. The mean survival time after the procedure was 204 days in the PRG group and 85 days in the PEG group (p<0.004). Respiratory function decreased more in the PEG group than in the PRG group (p<0.02).

CONCLUSIONS

PRG appears to be safer than PEG in ALS patients with moderate or severe respiratory impairment, and is followed by a longer survival.

Interaction between secondary velocities, flow pulsation and vessel morphology in the common carotid artery

The common carotid artery (CCA), one of the vessels more frequently investigated by ultrasound (US), is often modeled as a straight tube in quasi-laminar flow regimens. Experimental investigations based on a prototype multigate system show that blood velocity profiles are parabolic during diastole and early systole, and flat during the systolic peak. However, during late systole/beginning of diastole, they have an "M" shape, where the velocity near the walls is higher than in the vessel center. Moreover, the profile shape changes when the sound beam direction is moved over a given cross-section; thus, suggesting a nonaxisymmetrical velocity distribution, which contradicts the straight tube assumption. The purpose of this paper was twofold. First, the actual velocity distribution in "normal" CCAs was reconstructed. The analysis of several velocity profiles confirms that the velocity distribution is markedly asymmetrical, especially during the deceleration phase following the systolic peak. Second, a tentative explanation for such behavior is given by correlating it with the growth of secondary flows caused by the slight vessel curvature and viscous effects. This explanation is supported by the comparison between in vitro results and numerical solution of the Navier-Stokes equations in laminar pulsed-flow regimens.

Vascular reserve in the lower limbs of cirrhotic patients: a duplex Doppler ultrasound study

AIM

To evaluate femoral artery impedance at rest and during reactive hyperaemia.

PATIENTS

Study population comprised 11 cirrhotic patients without ascites, 10 with ascites and 16 age- and sex-matched healthy subjects.

METHODS

Echocardiographic assessment of systemic haemodynamics; duplex Doppler ultrasound measurement of femoral artery pulsatility index and vascular reserve [pulsatility index rest/pulsatility index hyperaemia).

RESULTS

Cirrhotic patients had elevated cardiac index and low systemic vascular resistance. Pulsatility index (right femoral artery) was not statistically different either at rest or after reactive hyperaemia (controls: rest 10.6 +/- 0.4, hyperaemia 2.6 +/- 0.2; compensated cirrhosis: rest 10.1 +/- 0.8, hyperaemia 3.4 +/- 0.4; ascitic cirrhosis: rest 11.4 +/- 1.6, hyperaemia 2.9 +/- 0.4. Vascular reserve was 4.38 +/- 0.35 in controls, 3.33 +/- 0.39 in compensated and 4.70 +/- 0.89 in ascitic cirrhosis (p = not significant). No correlation was found between systemic haemodynamic parameters and either pulsatility index or vascular reserve.

CONCLUSIONS

The lower limb vascular reserve is preserved in cirrhosis.

[Evaluation of patient doses in interventional radiology]

PURPOSE

To verify the suitability of indicative quantities to evaluate the risk related to patient exposure, in abdominal and vascular interventional radiology, by the study of correlations between dosimetric quantities and other indicators.

MATERIAL AND METHODS

We performed in vivo measurements of entrance skin dose (ESD) and dose area product (DAP) during 48 procedures to evaluate the correlation among dosimetric quantities, and an estimation of spatial distribution of exposure and effective dose (E). To measure DAP we used a transmission ionization chamber and to evaluate ESD and its spatial distribution we used radiographic film packed in a single envelope and placed near the patient's skin. E was estimated by a calculation software using data from film digitalisation.

RESULTS

From the data derived for measurements in 27 interventional procedures on 48 patients we obtained a DAP to E conversion factor of 0.15 mSv / Gy cm2, with an excellent correlation (r=.99). We also found a good correlation between DAP and exposure parameters such as fluoroscopy time and number of images. The greatest effective dose was evaluated for a multiple procedure in the hepatic region, with a DAP value of 425 Gy cm2. The greatest ESD was about 550 mGy. For groups of patients undergoing similar interventional procedures the correlation between ESD and DAP had conversion factors from 6 to 12 mGy Gy-1 cm-2.

CONCLUSION

The evaluation of ESD and E by slow films represents a valid method for patient dosimetry in interventional radiology. The good correlation between DAP and fluoroscopy time and number of images confirm the suitability of these indicators as basic dosimetric information. All the ESD values found are lower than threshold doses for deterministic effects.

On the interaction between ultrasound and contrast agents during Doppler investigations

Knowledge of interaction mechanisms between ultrasound (US) and contrast agents (CA) suspended in blood is important for a correct interpretation of clinical investigation results. Experiments performed in different laboratories have shown that, as a consequence of primary radiation force, CA tend to move away from the US transducer. Accordingly, Doppler spectra produced by particles suspended in moving water turn out to be significantly altered from what is theoretically expected. The purpose of this paper is twofold. First, an original model describing the bubble dynamics as the outcome of the balance between US radiation force and fluid drag force is validated for the case in which bubbles are suspended in blood. The high fluid viscosity is shown to prevent significant bubble deviations from the unperturbed fluid streamlines so that, in large vessels, a residual spectral distortion may exist only at the highest intensity levels permitted by current regulations. Finally, the relative importance and differences between the effect of primary radiation force and streaming mechanisms that, in principle, could lead to similar effects, are discussed.

A simplified approach for real-time detection of arterial wall velocity and distension

Arterial stiffness is known to increase with age and with many vascular diseases, but its noninvasive assessment in patients still represents a difficult task. The measurement of diameter change during the cardiac cycle (distension) has been proposed as a means to estimate arterial compliance and stiffness. Therefore, we have developed a simple PC-based device and algorithm for noninvasive quantification of vessel wall motion and diameter change in humans. This goal is achieved in real-time by processing the base-band signals from a commercial ultrasound Doppler system. Real-time operation is of crucial importance, because it allows a rapid achievement of optimal measurement conditions. The system was evaluated in a laboratory using a string phantom and was tested on the carotid arteries of 10 volunteers. Wall velocities from 0.05 to 600 mm/s and displacements lower than 2 microns were detected with phantoms. The measured carotid diameter change in the volunteers ranged from 7.5 to 11.8% (mean = 9.8%) and agrees closely with values reported in the literature. The difference between values taken one hour apart ranged from 0.2 to 0.5%. We conclude that the new system provides rapid, accurate, and repeatable measurements of vessel distension in humans.

Duplex scanning exploration of the ophthalmic artery for the detection of the hemodynamically significant ICA stenosis

BACKGROUND AND PURPOSE

The North American and the European Carotid Endarterectomy Trials demonstrated a significant benefit of surgery in preventing stroke for patients with symptomatic hemodynamically significant internal carotid artery (ICA) stenosis. Because the 3 angiographic methods of measuring carotid stenosis provide discrepant results, the indication for surgery depends on the method used for the evaluation of the angiogram. The goal of this study was to verify whether color duplex scanning of the ophthalmic artery alone might be reliable for detection of the extracranial hemodynamically significant ICA stenosis.

METHODS

Three groups of patients (351 total patients) with transient ischemic attack or minor stroke referred for possible carotid endarterectomy were examined by means of color duplex scanning of the ICA, transcranial Doppler, color duplex scanning of the ophthalmic artery, and angiography of the ICA.

RESULTS

In the first group (n=31) the comparison of findings from each method and the direct measurement of the residual lumen of plaque removed "en bloc" showed that the findings of the ophthalmic artery color duplex scanning, subdivided into 5 categories--NP (normal positive), LP (low positive), NF (no flow), REV (reverse flow), PP (pathological positive)--were associated with the best overall agreement (96.7%). The accuracy of the various categories of the ophthalmic artery color duplex scanning signals was studied in the second group of patients (n=200). The results pointed out that all but low positive categories were associated with high diagnostic accuracy. Finally, the results obtained in the third group (n=120) showed that a significant increase in the specificity of the low positive signal could be obtained by processing this signal in terms of pulsatility index and of transmission of pulsatility index.

CONCLUSIONS

Our results suggest that the diagnostic capacity of color duplex scanning for the detection of ICA critical stenosis can be appropriately increased if it is performed also at the level of the ophthalmic artery and if the Doppler signals are processed on the basis of criteria we applied.

Quantitative analysis of Doppler spectrum modifications yielded by contrast agents insonified at high pressure

In this report, the authors consider the modifications yielded in the Doppler spectrum when acoustic fields of increasing intensities are applied to encapsulated gas bubbles. Their in vitro experimental results show that the spectrum bandwidth is nearly proportional to the incident acoustic pressure, when its amplitude is maintained below about 200 kPa. At higher pressure levels, it even may happen that, in a steady, unidirectional flow (which should generate only positive Doppler frequencies), the Doppler spectrum is enlarged up to the point that negative Doppler shifts also are produced. Possible explanations in terms of either radiation force or streaming are discussed for this asymmetrical bandwidth enlargement.

Is there any relationship between cold-induced vasodilatation and vasomotion?

There are many analogies between cold-induced vasodilatation (CIV) and vasomotion (VM), but the demonstration of any relationship between these two microvascular homeostatic reactions is to date lacking. In a group of seven controls and seven patients with Raynaud phenomenon in the vasomotor stage of the disease, we studied, by means of laser Doppler fluxmetry, the fingertip flow at room temperature (15 min), during hand immersion into cold water (0-6 degreesC, 30 min), and at room temperature again (15 min). The Fourier spectral analysis of the laser Doppler signal revealed in both groups two different patterns of the fingertip flow oscillations: the first was characterized by continued oscillations with small amplitude and median frequency of 2-8 cycles/min occurring both at room temperature and during cold stimulation. The second was characterized by continued oscillations of high amplitude and median frequency of 1 cycle/4-6 min occurring during cold stimulation only. The first pattern of flow oscillations still occurred during the second. The high-frequency oscillations are similar to the waves of vasomotion and the low-frequency oscillations are similar to the waves of cold-induced vasodilatation. Because 90-98% of the fingertip flow passes through arteriolar-venular anastomosis (AVAs), our results suggest that the CIV flow oscillations may be an expression of the AVA's VM.

An FFT-based flow profiler for high-resolution in vivo investigations

Pulsed Doppler spectral analysis is a well-established diagnostic technique in the assessment of arterial diseases. Because of hardware limitations, its use has been so far restricted to the analysis of a single sample volume located along the ultrasound beam axis. In this paper, we discuss the operation of a newly developed multigate instrument capable of performing, in real time, 64-point fast Fourier transforms of Doppler signals sampled from 64 different range cells. The new instrument is capable of accurately detecting the actual blood flow behavior in major human vessels. Significant examples of velocity profiles obtained in real time from carotid arteries in healthy subjects are reproduced here for the first time. Multigate extension of spectral analysis is demonstrated to be a suitable means for detailed in vivo investigation of blood flow dynamics.

[Percutaneous gastrostomy. Personal experience in 137 cases]

Percutaneous gastrostomy is reported to be an effective alternative to total parenteral feeding or long-term nasogastric tube in the treatment of mechanical or functional dysphagia. The authors report their personal experience with 137 percutaneous gastrostomies performed on 98 men and 39 women from January 1986 through December 1993. All the maneuvers were performed under fluoroscopic guidance in the patients with head or neck cancer, neoplastic, vascular or post-traumatic neuropathy and upper GI tract cancer. To avoid left hepatic lobe trauma, percutaneous gastrostomy needs to be performed under US guidance. A 7F nasogastric tube is used to fill the stomach with air. After distending the gastric cavity, with the Seldinger technique under local anesthesia, fascial dilators of progressively increasing caliber are introduced into the gastric cavity and the final 12F gastrostomy catheter is positioned under fluoroscopic guidance. No major complications, such as hemorrhage or peritonitis, occurred. In one case, during the maneuver, the patient complained of severe epigastric pain which regressed with no further problems two hours later. In three cases the gastrostomy catheter fell out of place and was replaced by running the fistolous tract with a venous cannula and then a guidewire for gastrostomy repositioning. With this type of treatment, the patient can be given enteral feeding the following day. The maneuver requires approximately 10 minutes to perform and is well tolerated by the patient as it requires no general anesthesia. Percutaneous gastrostomy is more cost-effective than surgery or endoscopy and hospitalization is shorter. The only contraindications to this maneuver are hepatomegaly (because of the risk of liver trauma during percutaneous maneuvers), ascites (because of the risk of infection) and finally the complications resulting from gastric resection.

[Percutaneous treatment of hilar cholangiocarcinoma completed by high-dose rate brachytherapy. Experience in the first 5 cases]

Cholangiocarcinoma at the confluence of the hepatic ducts (Klatskin tumor) is a slowly growing malignancy with early onset of symptoms and poor outcome since surgery allows radical resection in only a minority of cases. Percutaneously placed biliary stents offer a good palliation, but tend to obstruct after 6-8 months; then, retreatment requires exchange of the endoprosthesis or establishment of a permanent external-internal biliary drainage which offers, in some patients, a relatively long survival. Percutaneous intraluminal HDR brachytherapy might be a valid alternative as a definitive therapy or as a method to keep metallic stents patent for a long time. Five patients with hilar cholangiocarcinoma, diagnosed by means of ultrasound, Computed Tomography, percutaneous transhepatic cholangiography and transluminal biopsy, underwent double percutaneous external-internal biliary drainage. Dummy sources were introduced into the drainage catheters to allow dose distribution planning. The stepwise progression of the miniaturized high activity Iridium source inside the applicators, introduced into the drainage catheters, was controlled and monitored by a computer equipped with dedicated software. In the radiotherapy bunker, using the remote loading technique, percutaneous intracavitary high dose rate brachytherapy was delivered at the rate of 750 cGy per fraction, prescribed at 1 cm from the center of the catheter, once a week, for 4 weeks. Nevertheless, only 4 of 5 patients underwent the complete treatment. In one case, radiation treatment was discontinued after the first session because of digestive bleeding from a duodenal ulcer, supposingly as a consequence of the decubitus of a catheter tip. CT demonstrated rapid progression of the disease with neoplastic spread to the omentum and gallbladder wall thickening; a gallbladder malignancy was then suspected and the patient was no more eligibile for brachytherapy. Subsequently, Carey-Coons endoprostheses were inserted to prevent post-actinic strictures and removed after three months. After completing radiation therapy, control cholangiograms demonstrated in all cases improvement of neoplastic strictures. The first two patients we treated show no signs of tumor recurrence at 4 and 1 months, respectively, after endoscopic removal of the stents. The third patient is still bearing 2 Carey-Coons endoprostheses to be removed after 3 months. The last patient with supposingly partial success of bracytherapy, was treated with two Strecker nitinol stents.

[The percutaneous treatment of the urological complications following kidney transplantation]

Renal transplantation is considered the treatment of choice in most cases of renal failure; the urologic complication rate ranges 1 to 10% in different surveys. This work was aimed at evaluating the application and results of interventional radiology in these cases. Since 1983, 24 patients (20 males and 4 females) whose age ranged from 18 to 63 years (mean age: 42 years) have been submitted to percutaneous maneuvers in our department. Thirty-four complications were treated: 14 stenoses, 11 fistulas, 7 urinomas and 2 transient obstructions. Complete success was obtained in 15/24 patients (62.5%), while 7/24 patients (29.16%) underwent reoperation and in 2/24 cases (8.34%) a definitive pyelostomy catheter was inserted. In 7 stenosis cases ureteroplasty was successfully performed and a double-J endoprosthesis inserted; the follow-up results (5-21 months) were satisfying in all cases. The only complication was one case of endoperitoneal hematoma. Considering the good results obtained, the low morbidity and mortality and the low cost, percutaneous maneuvers must be considered the treatment of choice in the urologic complications of renal transplants. When the percutaneous treatment of the main lesion fails, pyelostomy does nonetheless allow the drainage of urinary collections, the maintenance of renal function and the improvement of local and general conditions, which makes it easier to reoperate under elective conditions.

Fistulosphincterotomy in the endoscopic approach to biliary tract diseases

We report our experience with 49 patients who underwent fistulosphincterotomy (FS) after cannulation of the common bile duct (CBD) by standard approaches had failed, due to suspected CBD obstruction. Only 4% of our cases turned out to have no biliary obstruction at all. The morbidity rate was 16%, and the mortality rate was 2%. In our series, FS raised the success rate of CBD cannulation from 90% to 96%. Ninety-five percent of successful cannulations were followed by endoscopic treatment. There were no cases of perforation or hemorrhage, and no difference in the success rate between FS in flat papillas and FS in bulging papillas, thanks, perhaps, to the technique we used. Our findings would indicate that FS is a useful procedure involving additional but not prohibitive risks. Nonetheless, it should be used only when CBD obstruction is strongly suspected and standard methods are not successful.

Management of postoperative bile leakage with endoscopic sphincterotomy (EST) and a naso-biliary drain (NBD)

Between July 1987 and December 1990, 13 patients with postoperative bile leakage were treated with endoscopic sphincterotomy and a naso-biliary drain. All the leaks healed in two weeks, except for one (intrahepatic) that needed two months to heal in association with percutaneous management. The non-surgical treatment of bile leakage is the preferred approach on account of the superior safety, efficacy and cost-effectiveness as compared with surgical repair, which is associated with significant morbidity, mortality and costs. The treatment of choice has to be endoscopic, which is much easier and safer than the transhepatic approach, especially in the non-dilated duct, while another advantage over radiology includes the possibility for rapid definitive treatment of distal obstruction (e.g. residual stones). A leak from an extrahepatic duct heals rapidly, while a leak from an intrahepatic duct takes longer to heal and sometimes needs associated percutaneous drainage. Finally, the authors propose treating an extrahepatic bile leak merely with naso-biliary drainage without cutting the papilla, and an intrahepatic bile leak with endoscopic sphincterotomy, nasobiliary drainage and a bilio-duodenal endoprosthesis.

[Interventional radiology in the treatment of the complications from interventions on the lower urinary excretory tract]

Ureteral diversions may be complicated by strictures, hydronephrosis, pyelonephritis, lithiasis, fistulas, etc. In the last 10 years, 103 patients with 133 urological postoperative complications underwent percutaneous treatment. Most of the patients had been treated by percutaneous antegrade drainage; afterwards, stricture dilatation, ureteral stenting and stone extraction were performed. In one case a Strecker metallic stent was employed. We have successfully treated 101 of 133 complications (75.9%), with only 27 failures (20.3%). Five cases (3.8%) of lithiasis did not require percutaneous treatment. The good results obtained, the absence of major complications, the low cost and the little discomfort for the patients confirm the leading role of percutaneous treatment in complicated ureteral diversions.

[Percutaneous treatment of bile duct lithiasis. Personal experience in the first 150 cases]

Since 1983 we have percutaneously treated 150 cases of bile duct lithiasis in which previous endoscopic maneuvers had been incomplete or unfeasible. Complete resolution of lithiasis was obtained in 139 of 150 patients. In 6 cases only partial success was obtained but symptoms subsided. In 2 cases the treatment failed and the patients underwent surgery. Minor complications were observed in 12.6% of patients and resolved either spontaneously or by percutaneous maneuvers. Mortality rate was 2%. After a follow-up period of 6-12 months, 9 patients had a recurrence, completely resolved with further percutaneous treatment. These cases never required surgery. We obtained the best results in patients with stones residual after cholecystectomy or a iatrogenic stricture of the biliary tree. We obtained good results in massive lithiasis with combined endoscopic, surgical and radiological procedures. Morbidity and mortality rates were lower than in surgical series and similar to the endoscopic ones. The short hospitalization, the low cost and the possibility of treatment on an outpatient basis should promote the spreading of percutaneous techniques in the treatment of bile duct lithiasis.

[Tubal catheterization with selective salpingography in the diagnosis and therapy of fallopian tube obstruction]

Fallopian tube catheterization with selective ostial [correction of osteal] salpingography is a new technique for the diagnosis of tubal factors of infertility and also for the treatment of proximal tubal occlusion (PTO). In this study, 246 women were considered, 20-42 years old, with primary or secondary infertility, who presented a unilateral or bilateral PTO at hysterosalpingography (HSG). Catheterization and selective salpingography have been successful in 93.9% of the cases. Failures (5.6%) have been ascribed to obstructive organic diseases, where it was impossible to overcome the stenosis with the catheter or the guide-wire. Twenty-six spontaneous pregnancies were obtained (15 full-term deliveries) and 17 patients became pregnant after GIFT (13 full-term deliveries). At follow-up, after 12 months 4 of 10 patients had normal tubes, while 6 patients presented a new unilateral or bilateral PTO. No major complications occurred; nevertheless, ectopic pregnancy is a possible event, because of the mechanically re-established patency in a nonfunctioning tube.

[Treatment of postoperative biliary fistulas by endoscopic papillosphincterotomy and nasobiliary drain]

Personal experience in the non-surgical treatment of postoperative biliary fistulas observed between July 1987 and October 1990 is reported. Leakage were treated with an endoscopic technique (papillosphincterotomy+nasobiliary drain) in 11 of 12 patients in an average time of 2 weeks. The 12 patient, who presented a lesion of an intrahepatic duct, needed 2 months to heal following combined endoscopic-percutaneous manoeuvres. On the basis, then, of the good results obtained, it is recommended that in these cases, non-surgical treatment should be carried out on principle, choosing endoscopy as the initial access route.

[Endoscopic therapy of giant choledochal calculosis]

The paper reports the results of conventional endoscopic treatment in 100 consecutive cases of giant lithiasis of the common bile duct. A giant calculus is one whose dimensions exceed 2 cm. Endoscopic therapy proved successful in 73% of cases, with an 8% incidence of complications. The success of endoscopic treatment is related to the anatomical conditions of the biliary tract and the diameter of calculi. Mechanical lithotripsy has proved efficacious in all cases where it was used, whereas poor results were obtained using MTBE infusion through a naso-biliary tube. ESWL provided encouraging results. Cases which were not resolved using endoscopic methods were treated using intervention radiology or surgery, or both.

Ethanol-induced inhibition of carbachol-stimulated uptake of calcium in PC12 pheochromocytoma cells

Using a rapid-quench technique the effects of ethanol on the uptake of 45Ca2+ into PC12 pheochromocytoma cells were studied in suspension. At concentrations achieved during acute intoxication in man (25-100 mM), ethanol inhibited both the carbachol-stimulated and K(+)-induced uptake of calcium. Inhibition of carbachol-stimulated uptake of Ca2+ occurred rapidly, within seconds at 27 degrees C, whereas inhibition of K(+)-induced uptake of Ca2+ developed more slowly. This disparity between the kinetics of these ethanol-induced inhibitions was unexpected, because the uptake of Ca2+, evoked by either stimulus, is thought to occur predominantly through a common pathway, namely voltage-sensitive Ca2+ channels. This difference may reflect differential effects of ethanol on multiple carbachol-activated pathways for entry of Ca2+. Alternatively, carbachol may facilitate the inhibitory action ethanol on voltage-dependent channels. This apparent facilitation was manifested principally by a more rapid onset of inhibition, although the extent of inhibition by ethanol, in the presence of carbachol, was also increased. In preincubation experiments, ethanol did not enhance the apparent agonist-induced desensitization of carbachol-evoked uptake of Ca2+. Nevertheless, an acute interaction between cholinergic agonists and ethanol, affecting homeostasis of Ca2+ may play a role in the pathophysiology of alcohol intoxication.