Standards of practice: quality assurance guidelines for percutaneous treatments of intervertebral discs.

Percutaneous treatments are used in the therapy of small- to medium-sized hernias of intervertebral discs to reduce the intradiscal pressure in the nucleus and theoretically create space for the herniated fragment to implode inward, thus reducing pain and improving mobility and quality of life. These techniques involve the percutaneous removal of the nucleus pulposus by using a variety of chemical, thermal, or mechanical techniques and consist of removal of all or part of nucleus pulposus to induce more rapid healing of the abnormal lumbar disc. These guidelines are written to be used in quality improvement programs for assessing fluoroscopy- and/or computed tomography-guided percutaneous intervertebral disc ablative techniques.

Image-guided radiofrequency ablation (RFA) of unresectable hepatic tumors using a triple-spiral-shaped electrode needle: initial experience in 34 patients.

We evaluated the safety and efficacy of image-guided radiofrequency ablation (RFA) using a triple-spiral-shaped electrode needle for unresectable primary or metastatic hepatic tumors. Thirty-four patients with 46 index tumors were treated. Ablation zone, morbidity, and complications were assessed. The lesions were completely ablated with an ablative margin of about 1 cm. Five patients (14.7%) with a lesion larger than 4.5 cm had local tumor progression after 1 month and were retreated. Hemothorax, as a major complication, occurred in 1 of 34 patients (3.0%) or 1 of 46 lesions ablated (2.2%). RFA using this new electrode needle can be effective in the treatment of large unresectable hepatic tumors.

Microcatheter use for difficult percutaneous biliary procedures.

Percutaneous biliary drainage procedures in patients with nondilated ducts are demanding, resulting in lower success rates than in patients with bile duct dilatation. Pertinent clinical settings include patients with iatrogenic bile leaks, diffuse cholangiocarcinomas, and sclerosing cholangitis. We describe a method to facilitate these procedures with the combined use of a 2.7-Fr microcatheter and a 0.018-in. hydrophilic wire.

Patient and staff dosimetry in vertebroplasty.

STUDY DESIGN: Eleven vertebroplasty operations were studied in terms of radiation dose. OBJECTIVE: Doses to patients and staff associated with vertebroplasty were measured. Occupational doses were compared with the annual dose limits, and the effectiveness of the used radiation protection means was estimated. Patient dose was estimated by means of both surface and effective dose, and the radiation-induced risk was evaluated. SUMMARY OF BACKGROUND DATA: Vertebroplasty is a recent minimally invasive technique for the restoration of vertebral body fractures. It involves fluoroscopic exposure, and so, it demands dose measurements for both patient and staff exposed to radiation. METHODS: Thermoluminescent dosimeters (TLDs) were placed on the medical personnel and the effective dose was derived. Slow films were placed to patients' skin to measure entrance surface dose. Furthermore, a Rando phantom loaded with TLDs was irradiated under conditions simulating vertebroplasty, in order to estimate effective dose to the patient. RESULTS: Mean fluoroscopy time was 27.7 minutes. Patient's mean skin dose was 688 mGy, while effective dose was calculated to be 34.45 mGy. It was estimated that the primary operator can perform about 150 vertebroplasty operations annually without exceeding the annual dose constraints, whereas occupational dose can be reduced by 76% using mobile shielding. CONCLUSIONS: Measures have to be taken to reduce patient's skin dose, which, in extreme cases, may be close to deterministic effects threshold. The highest dose rates, recorded during the procedure, were found for primary operator's hands and chest when no shielding was used.

R2 relaxometry with MRI for the quantification of tissue iron overload in beta-thalassemic patients.

PURPOSE: To evaluate the usefulness of a time-efficient MRI method for the quantitative determination of tissue iron in the liver and heart of beta-thalassemic patients using spin-spin relaxation rate, R2, measurements. MATERIALS AND METHODS: Images were obtained at 1.5 T from aqueous Gd-DTPA solutions (0.106-8 mM) and from the liver and heart of 46 beta-thalassemic patients and 10 controls. The imaging sequence used was a respiratory-triggered 16-echo Carr-Purcell-Meiboom-Gill (CPMG) spin-echo (SE) pulse sequence (TR = 2000 msec, TE(min) = 5 msec, echo spacing (ES) = 5 msec, matrix = 192 x 256, slice thickness = 10 mm). Liver iron concentration (LIC) measurements were obtained for 22 patients through biopsy specimens excised from the relevant liver segment. Biopsy specimens were also evaluated regarding iron grade and fibrosis. Serum ferritin (SF) measurements were obtained in all patients. RESULTS: A statistically significant difference was found between patients and healthy controls in mean liver (P < 0.004) and myocardium (P < 0.004) R2 values. The R2 values correlated well with Gd DTPA concentration (r = 0.996, P < 0.0001) and LIC (r = 0.874, P < 0.0001). A less significant relationship (r = 0.791, P < 0.0001) was found between LIC measurements and SF levels. R2 measurements appear to be significantly affected (P = 0.04) by different degrees of hepatic fibrosis. The patients' liver R2 values did not correlate with myocardial R2 values (r = 0.038, P < 0.21). CONCLUSION: Tissue iron deposition in beta-thalassemic patients may be adequately quantified using R2 measurements obtained with a 16-echo MRI sequence with short ES (5 msec), even in patients with a relatively increased iron burden.

Jejunal diverticulitis with localized perforation diagnosed by ultrasound: a case report.

A rare case of a proximal jejunal diverticulitis is presented. The diagnosis was initially suggested by US and confirmed by CT. Ultrasound detected a hypoechoic irregular lesion continuous with the jejunum suggestive of the presence of diverticula. The presence of peridiverticular hyperechoic fat, associated with US signs of extraluminal air, evoked the diagnosis of a proximal jejunal diverticulitis, which was spontaneously walled-off. The diagnosis was confirmed by CT. The patient recovered after conservative treatment.

Percutaneous treatment of liver tumors with an adapted probe for cooled-tip, impedance-controlled radio-frequency ablation under open-magnet MR guidance: initial results.

Percutaneous radio-frequency (RF) ablation of liver tumors is usually performed under guidance of real-time US, but some tumor nodules in some patients cannot be adequately visualized with this technique. We report our preliminary results with an MR-compatible, internally perfused 17-G RF probe adapted to a standard RF generator for impedance-controlled RF ablation under MR guidance. Following initial testing of the probe for MR compatibility, artifacts and macroscopic effects on an ex vivo pig liver, four patients with eight neoplastic liver nodules (five metastatic and three primary), which could not be properly targeted by US, were treated with the cooled-tip technique under MRI guidance in an open 0.23-T magnet. Metallic artifacts produced by the probe were useful for accurate placement and did not interfere with MRI monitoring at the end of the procedure. Based on imaging findings, the immediate result of RF was considered adequate in all instances. Local recurrence occurred in one instance after 6 months, requiring repeat treatment. No adverse effects were noted. Initial experience suggests that the probe we used allows to perform impedance-controlled cooled-tip RF ablation of liver tumors under open-magnet MR guidance.

Radicular pain after vertebroplasty: compression or irritation of the nerve root? Initial experience with the "cooling system".

STUDY DESIGN: During vertebroplasty (VP), polymethylmethacrylate (PMMA) may leak into the posterior epidural venus plexus, provoking symptoms ranging from radicular pain to medullar compression. OBJECTIVES: To propose and test the feasibility of a procedure (cooling system) to prevent radicular irritation caused by foraminal PMMA leakage. SUMMARY OF BACKGROUND DATA: Foraminal leak of PMMA, as observed during VP, may lead to radiculalgia. Several mechanisms of nerve root irritation have been proposed. Considering heat or local chemical irritation has led us to treat immediately by local periradicular irrigation with a cooling liquid. METHODS: Four consecutive patients with observed foraminal leakage were treated by local fluid injection. Immediately after observation of a foraminal leak, a 20-gauge Chiba needle was positioned to reach the foramen. Ten cubic centimeters of lidocaine (0.2%) was followed by 100-200 cc of pressurized saline perfusion within 10-20 minutes (cooling system). RESULTS: In all patients with foraminal leakage, no radicular pain existed after application of the cooling system. No complications were observed with its use. CONCLUSION: In presence of a foraminal leakage, the immediate application of a cooling irrigation may protect the root from injury, which is explained by the hypothesis that the main mechanism of injury may be more related to heat or chemical irritation of the nerve than compression.