Endovascular embolization with radiopaque silk threads: a feasibility study in Swine

SUMMARY

Surgical suture endovascular embolization of brain arteriovenous malformations (AVMs) is an accepted method of preoperative treatment.A major drawback of AVM embolization with surgical sutures is that the sutures are not visible under fluoroscopy. An experimental study using swine is presented where surgical sutures were rendered radiopaque using platinum markers.

Allogeneic gene-modified tumour cells in metastatic kidney cancer. Preliminary report

An allogeneic irradiated RCC cell line, engineered to produce IL-2 (ACHN-IL-2), admixed with autologous metastatic formalin-treated tumour cells, was used to vaccinate ten MRCC patients in progression of disease in spite of IL-2 immunotherapy. The cells were administered subcutaneously and/or intra-tumourally. Sixty-four MRCC patients in progressive disease, not treated by vaccination but receiving similar IL-2 immunotherapy, were considered as the control group. Patients received 4-16 injections (mean 9 +/- 4), containing an average of 10.6 x 10(7) +/- 7.7 x 10(7) ACHN-IL-2-transfected cells (a minimum of 4 x 10(7), and a maximum of 31 x 10(7)). Four patients also received intra-tumour injections. Vaccination was administered during 30-418 days, and the follow-up continued for 649 +/- 353 days (190-1342). Throughout this period, the patients continued receiving the previously set immunotherapy treatment. No adverse side effects related to the treatment were observed. One complete and one partial tumour response were observed, as well as two stable and one no-relapse disease. All but one patient died. Responding patients resumed progression in 4-11 months and died 18 and 36 months after beginning the vaccine therapy. In spite of the small number of treated patients, Wilcoxon's test showed a significant (P < 0.05) improvement of the survival in the vaccinated group compared to that of the control. The described vaccination protocol seems safe, devoid of adverse side effects and promising. It warrants further investigation.

Endovascular treatment of pial AVMs: technical options, indications and limits in pediatric age patients

Our study group consisted of 29 patients who underwent endovascular treatment for the presence of pial AVMs. The patients were treated with various embolization methods including "-free flow" embolization (2 cases); embolization with suture threads (2 mm long micro-emboli: 17 cases) and embolization with acrylic glue (10 cases). There were significant angio-architectural and AVM location differences between the pediatric and the adult patient groups. In pediatric patients, the more frequent AVMs were of the mono or few-pedunculated type, then simple direct fistulas and high-flow fistulous-plexiform AVMs and giant infra-tentorial or deep-seated malformations. In mono or few-pedunculated AVMs, the elected treatment was acrylic glue followed by radio-surgery achieving definitive cure in 3 cases. In direct AVFs and elevated flow AVMs, embolization with suture and acrylic glue offered definitive results. Treatment for infra-tentorial and deep-seated AVMs presented the greatest difficulty in pediatric patients. In two of them, embolization with glue enabled radiosurgery (giant cerebellar AVMs). Our experience did not confirm that current endovascular techniques provide definitive treatment in extensive, deep-seated AVMs. Each treatment, in children more so than in adults, requires a risk/benefit evaluation of the method taking into account the natural history data.

Digital subtraction angiography for arteriovenous malformations in stereotactic radiosurgery

Images coming from digital subtraction angiography (DSA) are affected by a perspective distortion due to the use of image intensifiers. As a result, DSA cannot be used for the accurate definition of stereotactic coordinates. A correction method has been developed to enable the use of DSA for the radiosurgery of arteriovnous malformations. A software program and a special phantom tool were employed. The phantom is made by a computer-controlled drilling machine which makes holes in a Plexiglas plate. It has 865 calibration steel spheres with coordinates determined with a precision of 0.01 mm. A calibration image is acquired by a personal computer, and the software calculates the transformation algorithm to superimpose the image on the known positions of the phantom. This algorithm is saved and then recalled to transform the diagnostic images.

Gamma Knife stereotactic radiosurgery of ocular metastases: a case report

A case of a choroidal metastasis treated with Gamma Knife stereotactic radiosurgery is reported. A 48-year-old Caucasian man afflicted with lung cancer (adenocarcinoma) was referred to the University Hospital of Verona, Italy, for loss of vision in his left eye due to a choroidal mass with exudative retinal detachment. Clinical investigation was conclusive of a well-defined, bilobed choroidal metastasis located in the temporal and inferior portion of the posterior pole of the eye. The lesion was characterized by a maximum thickness of 5.2 mm and a maximum lateral extension of 14 mm. The staging was negative for other metastatic localizations. Using the Gamma Knife technique, a surface dose of 25 Gy was administered at the 50% isodose line using the 8-mm collimator (5 shots) with equally weighted fields. After a 3-month follow-up period, a marked reduction in the lesion size as well as in the exudative retinal detachment was observed. This improvement was unchanged 6 months after the treatment, and the lesion appeared completely controlled. To the best of our knowledge, this is the first case report of an ocular metastasis treated with stereotactic Gamma Knife radiosurgery.

Stereotactic radiosurgery of uveal melanomas: preliminary results with Gamma Knife treatment

Twelve cases of uveal melanoma (T3N0M0:11 patients, T4N0M0:1 patient) treated with Gamma Knife stereotactic radiosurgery are reported. Our protocol includes preoperative ocular and systemic assessments with complete ocular examination, ophthalmoscopy, fundus photography, fluorangiography, standardized echography, CT and MRI, chest X-rays, liver echography and blood tests. The follow-up program is mainly based on echographic evaluation of tumor thickness and size. The procedures include fixation of the eye, application of the stereotactic Leksell frame G, CT/MRI localization of the melanoma, dose planning and treatment with the Gamma Knife (B type). A mean surface dose of 55 +/- 10 Gy was administered at the 60-90% isodose curve using 4- to 14-mm collimators and a number of shots ranging from 1 to 6. A significant reduction (10-41%) in echographic thickness of the tumor was shown in 6 cases with a follow-up of 3-12 months. In 4 patients, the tumor size was still unchanged after 1-10 months. The single high-dose radiation delivered to the target and the high spatial accuracy are the main advantages of stereotactic radiosurgery for the treatment of posterior uveal melanomas. A longer followup is needed to further validate this new application of Gamma Knife radiosurgery.

Quality assessment of magnetic resonance stereotactic localization for Gamma Knife radiosurgery

Artifacts in magnetic resonance imaging (MRI) may lead to anatomical distortion and inaccurate stereotactic coordinates. A special phantom for MRI and computed tomography (CT) was built to test the quality and precision of the two neuroradiological procedures. The phantom is fixed with the Leksell frame, and it has 15 orthogonal markers visible by CT and MRI techniques. The coordinates of the markers were calculated first on the CT scans and then on MR images. Two groups of different distortions were analysed: artifacts depending on the frame and its components and artifacts depending on the MR unit and image characteristics. A good target-coordinate correlation was found between CT and MRI in the axial plane, while in the coronal plane there was always a small error. This error is not constant, but changes from test to test, consequently it is hard to reform the image.

Interventional neuroradiology for the treatment of inaccessible arterio-venous malformations

Embolization of cerebral arterio-venous malformations (AVM) has been performed at the Department of Neuroradiology of Verona in 136 patients with a total of 310 procedures. The complication rate was 16%. In most of the cases embolization was followed by either operative removal of the AVM or by radiosurgery. In a group of 38 embolized patients, who refused operation or radiosurgery, rebleeding occurred 7 times (18%), but only in patients who already had bleedings before embolization. Indications and techniques of embolization are described and discussed.

Treatment of cerebral arteriovenous malformations with a combination of preoperative embolization and surgery

Forty-nine patients with cerebral arteriovenous malformations (AVMs) were treated with preoperative embolization followed by resection using a microsurgical approach. In 27 patients, the AVM was located in an eloquent area; in 32 patients, the volume of the AVM was over 20 cm3. Preoperatively, flow-directed embolization was performed in 10 patients (28 procedures), selective embolization with threads was performed in 35 patients (46 procedures), and a combination of flow-directed and selective embolization was performed in 4 patients (12 procedures). The percentage of reduction of the AVM volume averaged 36% after embolization. Five minor complications (transient neurological deficits, in 2 cases associated with ischemic areas on the CT scan) were observed after embolization. The interval between the last embolization and surgery was as follows: within 10 days in 7 patients; between 11 and 20 days in 3 patients; between 21 and 30 days in 10 patients; between 31 and 60 days in 11 patients; and 2 months later in 18 patients. The efficacy of this combined treatment (embolization plus surgery) was evaluated by the incidence of hyperemic complications and the clinical outcome. Hyperemic complications occurred more frequently in patients with an AVM volume greater than 20 cm3. When compared with flow-directed embolization, selective embolization was linked with decreased bleeding during surgery; postoperatively, the incidence of cerebral edema was also lower. Clinical outcome was better after selective embolization, with no occurrence of major deficits and no mortality. When the percentage of reduction of the AVM volume after embolization was 40% or more, the incidence of intraoperative hyperemic complications was lower; moreover, new permanent deficits were never observed in patients with this volume reduction. A retrospective clinical comparison of two groups of patients with similar AVM volumes (greater than 20 cm3)--those given combined treatment (n = 32) versus those treated by direct surgery alone (n = 27)--showed that intraoperative bleeding appeared to decrease in patients treated by embolization; the incidence of postoperative hyperemic complications was not different in the two groups. New major deficits and deaths were less frequent in patients treated by embolization (P = 0.05 for the incidence of major deficits); postoperative epilepsy was also less common in these patients. In conclusion, combined treatment with selective preoperative embolization and direct surgery may help the neurosurgeon in the treatment of large, high-flow AVMs, reducing the risks connected with their surgical removal.

[Idiopathic restrictive cardiomyopathy: clinical, hemodynamic, histologic and prognostic profile]

Idiopathic restrictive cardiomyopathy is a rare myocardial disease characterized by restrictive physiology without a specific histologic basis. To assess its clinical, hemodynamic, morphologic and prognostic details we retrospectively evaluated all the patients hospitalized in our Institute from 1974 to 1988. Nine patients, aged 42 +/- 16 years, M/F ratio = 0.29, who represent 64% of all the restrictive myocardial diseases biopsied were identified. Severe cardiac heart failure (3-4 NYHA) and arrhythmias (ventricular and supraventricular) were extremely common. The electrocardiogram showed several non specific signs: low voltage of QRS in peripheral leads (4/7), pseudo-infarctional aspects (3/7), mono or biventricular hypertrophy (3/7) disturbance of ventricular conduction (3/7), aspecific abnormalities of ventricular repolarization (3/7). All patients showed a prolonged QTc. M-mode and 2-dimensional echocardiography demonstrated in 6 cases biatrial enlargement, normal or slightly enlarged ventricles, normal or moderately depressed fractional shortening; biventricular concentric hypertrophy was detected in 3 cases, asymmetrical septal hypertrophy in 1. Five patients showed pericardial effusion. Cardiac catheterization disclosed an increase of left and right ventricular end-diastolic pressures (8/8) with a dip-plateau pattern and/or characteristic W waveform in the atrial pressure tracing (9/9). Passive pulmonary hypertension was detected in 6/9 cases. The cardiac index was decreased in 4/8 cases. Left ventricular angiography showed mitral regurgitation in 5/8 patients, tricuspidal in 5/8. Ejection fraction was decreased in 3/8 cases. Endomyocardial biopsy showed interstitial fibrosis (8/9), cellular hypertrophy and/or nuclear alterations (7/9), slight endocardial thickening (2/9). At a mean follow-up of 22 +/- 15 months 3 patients died and 2 underwent heart transplantation. In conclusion idiopathic restrictive cardiomyopathy is one of the most frequent forms of restrictive myocardial diseases in our geographic area. Severe congestive heart failure and arrhythmias are extremely common. The disease can be suspected by clinical, electrocardiographic and echocardiographic features, but the final diagnosis requires cardiac catheterization and endomyocardial biopsy. Prognosis is severe and heart transplantation must be considered in the cases with severe heart failure.

Interventional angiography in neuropediatrics

Since the introduction of non-invasive imaging techniques (CT, US, MRI), superselective cerebrospinal angiography has been playing a major role as a diagnostic tool as well as a therapeutic procedure prior to surgery or as an alternative. Surgical neuroangiography is now also a well-established therapeutic technique in neuropediatrics. Lesions fed by the external carotid artery and spinal cord lesions are the main indications. The first group consists of maxillofacial vascular malformations, nasopharyngeal angiofibromas, and vascularized tumors of the facioorbital area (hemangiopericytoma, angiosarcoma ...). Spinal lesions for which embolization can be considered are benign tumors of the vertebral column (vertebral hemangioma, aneurysmal bone cyst ...) and vascular malformations intrinsic to the spinal cord. Particles (Ivalon, dura) are the safest embolization materials and have a wide range of possible applications; glues such as IBC have defined but limited indications. Digital subtraction angiography is crucial during the procedure and in determining the overall doses of contrast medium to be administered. Furthermore, decisions can be made more rapidly and precisely, with a definite improvement in the therapeutic results.

Preoperative embolization of arteriovenous malformations with polylene threads: techniques with wing microcatheter and pathologic results

The technique with a wing microcatheter system and the pathologic aspects of 11 cerebral arteriovenous malformations (AVMs) surgically resected after embolization with polylene threads are reported. Embolization was performed once in eight patients and twice in three patients. Resected AVMs were submitted both to routine hematoxylineosin examination and to immunohistochemical workup in order to detect the type of immunologic response to thread emboli. In nine cases, 50% or more of the nidus was obliterated by the embolization. After embolization two patients developed reversible neurologic deficits. Pathologic specimens of resected AVMs demonstrated no vascular necrosis; however, a moderate inflammatory response could be seen, characterized by the presence of both mononuclear cells and foreign-body giant cells, associated with the absence of polymorphonuclear infiltrates. A granulomatous fibrotic process was identified that was present from the first month after embolization. Immunohistochemistry indicated that the immunologic response to thread emboli was cell-mediated, not humoral. Embolization with the wing microcatheter with the use of polylene threads proved to be a safe and efficient system of embolization, as a preoperative procedure. Polylene threads are a nontoxic and biocompatible material that can be used as an embolic agent for brain AVMs.

Oncocytoma and low-grade oncocytic carcinoma of the kidney

Oncocytoma is a term generally used to describe a neoplasm of the renal parenchyma consisting of well-differentiated cells with prominently eosinophilic granular cytoplasm. We report our experience with such tumors and with 4 cases of granular cell carcinoma (grade 2). We present the histopathology, surgical staging studies, treatment, and clinical outcome. Of the 10 patients, 7 are alive without evidence of tumor at a mean follow-up of 5 years from the initial treatment. Three patients have died, 2 from nontumor-related causes while the cause of death of the third patient is uncertain, possibly due to the tumor. Although well-differentiated oncocytic renal tumors are usually considered as uncommon when the diagnosis is made, nonaggressive behavior is expected. However, careful radiographic and pathologic examination is required to avoid the pitfall of overlooking a higher-grade, more lethal neoplasm which may be mixed with the well-differentiated oncocytic neoplasm and form a minority component. A wide resection, which in most cases is nephrectomy, is apparently curative and assures that complete pathological examination of the specimen can be accomplished. In more than 90% of the cases, the tumor is solitary and unilateral. Cases in which there are multiple tumors are often bilateral, and this finding may create diagnostic confusion.

Spontaneous arterio-venous fistulae of the vertebral artery. Diagnostic and therapeutic considerations

Spontaneous arterio-venous fistulae of the vertebral artery are rare. These lesions mainly affect the upper cervical area, and are usually asymptomatic, or may present as small, often pulsatile, cervical masses with vascular murmurs. The authors report on two cases in which the presumptive diagnosis, suggested by venous digital subtraction angiography, was then confirmed by selective angiography. In both cases an intravascular approach with detachable balloons and particulate substances was carried out, with good anatomical and functional results. Problems related to diagnosis, pathophysiology of symptoms, indications for treatment and embolization techniques are discussed.

Sarcomatoid carcinoma of the kidney

Among 315 cases of parenchymal renal carcinoma resected between 1975 and 1985, 19 cases (6 per cent) of sarcomatoid carcinoma were identified. All patients were symptomatic or had a palpable mass in the flank at hospitalization. Tumor stage generally was advanced at operation and metastases were detected in 8 patients (Robson stage IV), all of whom died after an average postoperative survival of 8 months. In 3 patients there was tumor invasion of the renal vein (Robson stage IIIA), and they died after an average postoperative period of 11 months. Of 4 patients with perinephric fat invasion (Robson stage II) 2 died of cancer after an average survival of 15 months and 2 are alive with no evidence of disease for an average of 73 months postoperatively. In these later 2 cases the sarcomatoid areas constituted less than 5 per cent of the entire tumor and the remaining tumor was low grade carcinoma. In 3 patients adequate followup is not available and 1 was lost to followup. This histological variant of parenchymal cell carcinoma is a high grade malignancy with a poor prognosis. Operative treatment appears to be ineffective in modifying the behavior of the tumor.

CNS trauma: head injuries

Head injuries are a common cause of death and permanent disability, particularly in the first decades of life. The high mortality and morbidity associated with head trauma is due mostly to the severity of the injury itself but also in part to the possible events that could aggravate the primary brain damage. This also occurs in patients with an initially mild head trauma. This article reviews imaging procedures, complications of head trauma, and the order of diagnostic evaluation.

Treatment of posttraumatic carotid-cavernous fistula using a detachable balloon catheter

Five cases of posttraumatic carotid-cavernous fistula are reported. The fistulas were occluded by intravascular detachable balloons, as described by Serbinenko and later modified by Debrun. The good results obtained in three of these patients illustrate the value of this procedure, as it allows a direct obliteration of the fistula with preservation of the internal carotid blood flow.

Computerized axial tomography (CAT) in cerebral ischemia

The CAT shows the site, extension and evolution of cerebral ischemic lesions, and implies no risk or pain for the patient. Cerebral ischemic lesions appear as dark, hypodense areas on the brain section planes and are well differentiated from the white hyperdense areas of hemorrhagic lesions. In the territory of the middle cerebral artery the symptomatology is well related to the extension of the lesions, but not to their site when they are 'limited'. At present the CAT is essential for the treatment of cerebral ischemic lesions.