T. Mygind

Percutaneous Gastrostomy Guided by Ultrasound and Fluoroscopy

Percutaneous gastrostomy, utilizing a dedicated catheterization kit, with a combination of ultrasonographic (US) and fluoroscopic guidance, was carried out in 27 patients. The main indication for gastrostomy was the need for nutritional support in malignant esophageal stricture. After distending the stomach with water via a nasogastric tube, the gastric antrum was punctured under US guidance and a guide wire was inserted, followed by fluoroscopically guided tract dilatation and insertion of a 2.5-mm Cope-loop catheter. In all patients but one (96%) the procedure was successfully completed in one or 2 attempts. Two complications occurred: one case of a small subcutaneous abscess near the puncture site, and one late incident of dislodgement of a catheter without string-loop fixation, which had been inserted at a catheter exchange after 6 weeks. Percutaneous gastrostomy guided by US and fluoroscopy is a safe and efficacious alternative to endoscopic and surgical gastrostomy.

The Transplanted Kidney: Diagnostic and Interventional Radiology

Following kidney allotransplantation a great number of complications threaten the patient and his graft, e.g. acute tubular necrosis, acute and chronic rejection, urologic and vascular complications and complications due to the immunosuppressive treatment. During the last decade a number of technical developments in radionuclide, ultrasonographic and radiographic imaging and intervention has significantly improved the possibility of early recognition and handling of such complications. Knowledge of the capability and limitations of the various techniques is of vital importance for their rational use. The aim of this review article is to give a short description of the various imaging modalities, the rational monitoring of the post-transplant patient, and possible handling of complications by the aid of imaging techniques.

Doppler ultrasound assessment of TIPS patency and function--the need for echo enhancers.

Purpose: the aim of this study was to illustrate the versatility of an i.v. administered echo enhancer for Doppler US assessment of TIPS patency and function. Material and Methods: A total of 22 Doppler US evaluations of TIPS patency and function were performed in 5 patients with alcoholic cirrhosis and recurrent oesophageal bleeding who had been treated with TIPS. TIPS patency was evaluated by means of colour or power Doppler US. the volume flow (VF) was assessed in the TIPS and in the portal vein by spectral Doppler. the ratio of the VF in the TIPS to the VF in the portal vein (T/P ratio) was used to express the functional status of the TIPS. If Doppler signals were inconclusive or absent, echo-enhanced US was performed. Results: In 22 follow-up Doppler US examinations, echo-enhanced Doppler US was required in 7 cases (29%). the Doppler enhancement persisted in the range of 3–5 min. No adverse effects were observed. An apparently normal TIPS function reflected a T/P ratio in the range of 0.44-1.10, median 0.78 ± 0.20 (2SD). Conclusion: the i.v. administration of echo enhancers would seem to be indicated in the assessment of the TIPS function if conventional Doppler US fails to prove normal TIPS patency and function. the T/P ratio may be a convenient monitoring parameter for reflecting the TIPS function.

Expandable Metallic Endoprostheses for Biliary Obstruction

Expandable metal stents (20 Gianturco Z-stents and 1 Strecker stent deployed through 8.5 F sheaths) were used with initial success for palliating bile duct obstruction in 10 patients, 8 with malignant and 2 with benign strictures. Short-term failure occurred in one patient after 2 weeks, one died of unrelated causes after 10 days, and one remained jaundiced due to fulminant liver metastases. In the remaining 7 patients the obstruction was markedly palliated, with normalization of the serum bilirubin. Four have died without recurrent bile duct obstruction after a mean of 5.9 months, the 2 with benign strictures are well after 4 and 7 months, and one patient is presently palliated with a plastic endoprosthesis following reocclusion after 4 months. Expandable stents were easier to insert than conventional percutaneous endoprostheses of plastic polymers, and had longer patency in several patients, but reocclusion by tumor growth remains a constant threat in malignant disease. Metallic stents may be the therapy of choice in recurrent benign strictures, although the definitive conclusion needs longer observation and larger materials.

Radiographic Evaluation of the Urethral Kock Ileal Bladder Substitute

Fifty male patients who had undergone bladder substitution with a urethral Kock pouch after radical cystectomy for bladder cancer, were evaluated in the immediate postoperative period by retrograde pyelography and pouch cystography, and at later follow-up by pouch cystography. Other radiologic procedures (urography, ultrasonography, CT, etc.) were not part of a routine program, but were used when clinically indicated. In 12% a ureteroileal anastomotic leakage was found; the leaks resolved with continued ureteral stenting. Extravasation at the anastomosis between the pouch and the urethra was seen in 55% at the first cystography. It resolved within one month in all cases by simply leaving a catheter in the bladder. On the late cystograms reflux was observed in 6% of patients, whereas stone formation in the pouch was not encountered. A careful radiologic follow-up of patients with urinary diversions is essential to minimize postoperative complications.

Effects of intravenous injection of diatrizoate, iohexol or ioxilan on renal size, urine profiles and blood profiles in the rabbit

Diatrizoate, iohexol or ioxilan were injected intravenously in 18 rabbits. The contrast medium passage through the kidneys was recorded on digital subtraction images for the first 50 s followed by 100 mm exposures up to 15 min after injection. The renal area was measured planimetrically. Urine profiles (glucose, phosphate, LDH, GGT, NAG), blood profiles (potassium, urea) and the relative clearance of albumin and sodium were followed for 5 days and compared with a control group injected with saline. All kidneys were examined by light and immunofluorescence microscopy. All three contrast media produced excellent arteriograms and urograms. The three different contrast media caused a rapid increase of the kidney area within the first minute, reaching an average maximum of 10 to 12 per cent after 5 min, followed by a gradual decline. Contrary to expectations the increase in renal area was similar for all three contrast media, so hyperosmolality is no likely explanation of this phenomenon. None of the contrast agents caused significant changes in any of the profile components with one exception: the GGT excretion was significantly elevated during the first 24 h after diatrizoate administration as compared with the effect of saline. Light and immunofluorescence microscopy revealed no differences.

Subtraction Nephrotomography during Urography of Transplanted Kidneys

Hypocycloid tomography with photographic subtraction was applied during the early nephrographic phase of urography in 48 transplanted kidneys. The quality of demarcation between cortex and medulla in the subtracted nephrotomogram was evaluated and categorized into 4 groups: Excellent, good, poor, and absent demarcation. The renal function determined by 24-h endogenous creatinine clearance did not correlate with the quality of demarcation. Among 30 cases with excellent or good demarcation only one patient experienced rejection within 8 days after the urography. In 18 cases with poor or absent demarcation 9 had an episode of rejection. Absence of demarcation was only observed in this group of patients. Segmental renal infarcts were demonstrated occasionally on the subtracted early nephrotomogram. Thus, tomographic demonstration of the initial distribution of contrast medium in a transplanted kidney may prove to be of value in the diagnosis both of rejection of transplanted kidneys and renal infarcts.

Flow measurements with digital subtraction densitometry in a steady flow experimental model

Computerized densitometry was applied on digital subtraction series for measuring flow rates, 600 to 2,000 ml/min, in model experiments, using contrast medium as indicator substance. A total of 962 measurements were performed, employing the Stewart-Hamilton dilution technique, as well as direct measurements of velocity of the indicator bolus between 2 measuring sites. Results with the dilution technique were closely correlated with true values, but slightly lower (mean 8%), presumably because of sedimentation of contrast medium. Measurements based on bolus velocity were most accurate when the bolus passage was defined by points near the gravity line of the area under the concentration curve. Use of more easily identified curve points, e.g. the time of curve maximum, tended to yield too high values due to flow laminarity with a high-velocity leading edge of the indicator. Variation in repeated measurements on any single image series was attributed to the low sampling rate.

Low-field MR imaging (0.1 T) in patients with clinically suspected acute spinal block

The diagnostic usefulness of a 0.1 T MR unit in patients with clinical suspicion of acute spinal block was studied in 59 patients who were referred to acute MR investigation. The records were reviewed retrospectively 1 month after the MR for assessing the clinical impact of the examination. Ninety-eight per cent had a true-positive examination confirmed by surgery (21%) or observation (77%). In 60% of the patients the MR imaging had a therapeutic consequence. In only one patient did the level of visualised pathology at the MR examination not correlate with the clinical findings; the patient subsequently refused surgical treatment. We conclude that a low-field MR unit is excellent for acute examination of patients clinically suspected of acute spinal block.

Percutaneous Transhepatic External Biliary Drainage Utilizing a Pig Tail Balloon Catheter

A 2.3-mm soft pig tail balloon catheter was developed to be used for percutaneous transhepatic biliary drainage. A small balloon (OD 10 mm) secures an optimal internal fixation and side holes behind the balloon secure drainage of the cannulated bile duct peripheral to the balloon. Successful transhepatic biliary drainage with the pig tail balloon catheter was achieved in 11 of 12 patients for a period of 3 to 67 days (median 6 days). In one patient the catheter clogged after 55 days of drainage. No case of catheter dislodgement or other complications related to the external drainage was seen.