[Localized neuropathic pain--5% lidocaine medicated patch as a first-line treatment and as add-on therapy: literature review and personal experience]

Localized neuropathic pain (LNP) is a type of neuropathic pain characterized by consistent and circumscribed area(s) of maximum pain, which are associated with negative or positive sensory signs and/or spontaneous symptoms typical of neuropathic pain. This description outlines the clinical features of a group of pathologies, in which a LNP can be diagnosed and for whom topical targeted treatment with 5% Lidocaine medicated plaster can be suggested. Indeed both American as well as European guidelines already suggest 5% Lidocaine medicated plaster as a first line treatment in post herpetic neuralgia and in general in the treatment of conditions such as diabetic painful polyneuropathy and post surgical pain where a LNP can be ascertain. In a daily practice of a Pain Unit however the usual case mix encompasses also other causes of LNP, most of them with a scanty pain control in spite of a ongoing polytherapy. Aims of this paper were to focus on 5% Lidocaine medicated plaster as a first line treatment in LNP and to add new insight on its possible use as add-on therapy reporting our data on a consecutive series of 42 patients affected by LNP under unsatisfactory polytherapy in which 5% Lidocaine medicated plaster was able to achieve a satisfactory pain control.

Relationship between function and perfusion early after acute myocardial infarction

To assess the relationship between baseline left ventricle function, functional reserve and resting myocardial perfusion in patients with acute myocardial infarction (AMI). After AMI the presence of dysfunctioning but viable myocardium plays a determinant role in clinical outcome. Regional ventricular function was evaluated by echocardiography both in resting conditions and during dobutamine infusion (10 microg/kg/min). Perfusion was assessed by magnetic resonance imaging in a single slice approach where the first pass of an intravenously injected bolus of gadolinium-based contrast agent was followed through six regions of interest within the myocardium. In each patient a region with normal function was used as reference and the cross-correlation coefficient (CCC), which described the myocardial perfusion relatively to the reference region (CCC = 1 means equivalent perfusion), was obtained for the other five myocardial regions. Twenty-two patients were enrolled into the study. Sixty-one segments had normal function and normal perfusion (CCC = 0.92+/-0.23). The perfusion deficit was more marked in the 29 regions with resting akinesia-dyskinesia than in the 20 hypokinetic regions (CCC = 0.71+/-0.45 vs. 0.84+/-0.23; p < 0.05). Out of the 29 regions with resting akinesia-dyskinesia the 13 segments which showed functional improvement following dobutamine had a higher resting perfusion than the 16 segments which were unresponsive to dobutamine (CCC = 0.83+/-0.32 vs. 0.61+/-0.52, p < 0.05). Similarly, out of the 20 regions with resting hypokinesia the 11 segments having functional reserve showed an higher resting perfusion than the segments which did not (0.96+/-0.21 vs. 0.69+/-0.19; p < 0.05). Early after AMI, the perfusion deficit reflects the severity of the mechanical dysfunction. In regions with baseline dyssynergy resting perfusion is, in general, higher when contractile reserve can be elicited by stress-echo.

[Tumor samples as a tool for large-scale monitoring of antigen-specific lymphocytes in gastric and colorectal neoplasms]

The characterization of tumor-associated antigens has enabled to direct the host immune response towards the autologous tumor through appropriate loading and presentation of the antigen. In vivo conditions that generate large numbers of tumor antigens would be an important step in vaccine strategies. In this study we have therefore tested the ability of freshly isolated gastric and colorectal cancer cells to induce a specific anti-tumor response in autologous T lymphocytes. Because dendritic cells (DC) are critically involved in both initiating and boosting host immune responses, they have been used to present apoptotic bodies generated by irradiated tumor cells. Results show that these native antigens stimulate T cytotoxic response against tumor, but not peritumor normal tissues. Induction of IFN-gamma secreting cell activity, which is a standard readout in current cancer vaccine protocols, was also demonstrated by Elispot single-cells assay. These data show the antigenicity of gastric and colorectal tumor cells and open new perspectives in immunotherapy.

[Magnetic resonance with an endorectal coil and a fast spin echo sequence in the staging of prostatic carcinoma. The correlation with histopathological data]

INTRODUCTION

We investigated the accuracy of endorectal coil Magnetic Resonance Imaging (MRI) and Fast Spin Echo (FSE) technique in staging prostate cancer.

MATERIAL AND METHODS

MRI was performed in 70 patients with biopsy proved prostatic cancer. A total of 33 patients subsequently underwent radical prostatectomy. T2-weighted FSE sequences (TR 3400-4100, TE 120, Echo train length 13) were acquired in all patients. Axial, sagittal and coronal 4-5 mm images were obtained with 13-14 cm field of view and 256 x 256 matrix. Additional T1-weighted spin echo images were acquired in 9 patients. Lesion staging on MR images was performed according to the American Urological System. MR data were compared with the pathologic findings of whole-mount sections of the surgical specimens.

RESULTS

Overall accuracy for endorectal coil MR imaging was 60%; ten cases were underestimated and 3 cases were overestimated. The sensitivity and the specificity of endorectal coil MRI in diagnosing capsular penetration were 77% and 81%, respectively. Seminal vesicle invasion was detected with 87% sensitivity and 96% specificity.

CONCLUSIONS

Endorectal coil MRI provides a more accurate preoperative local staging.

[Subdural effusion during bacterial meningitis]

Twelve children of age ranged from 4 to 34 months with Haemophilus influenzae type b meningitis treated at Meyer Hospital of Florence, were retrospectively reviewed. Eight patients had subdural effusion demonstrated with TC, RM and transfontanellar ultrasonography. All patients are cured without sequelae.

Ultrasound-guided alcoholization of celiac plexus for pain control in oncology

BACKGROUND

Treatment of inoperable pancreatic cancer pain is of paramount importance. The ineffectiveness of pharmacological agents has led many investigators to recommend chemical neurolysis of the celiac ganglions for pain control. This procedure may be performed under either fluoroscopic or computed tomography (CT) guidance, or it may accompany laparotomy. The authors describe a modified sonographically (ultrasound-US)-guided technique for alcoholization of the celiac ganglions.

METHODS

Twelve patients underwent the neurolytic procedure. Nine of 12 suffered from pancreatic cancer. The remaining three were affected by inoperable hepatic, gastric, or colon cancer, respectively, with multiple hepatic metastases. US-guided alcohol neurolysis was performed by an anterior approach. In the last four patients, PIA (percutaneous injection alcohol) needles, modified by the authors, replaced the spinal needles employed in the first eight patients to inject the alcohol. Pain and pain relief were rated according to a Simple Descriptive Scale (SDS), and treatment success was gauged by declining opiate doses and need for pharmacological therapy. Results after treatment performed using different needles were compared.

RESULTS

Procedure-related mortality was zero. Complications of the neurolytic procedure included left pleural effusion in one patient and mild diarrhea in two other patients. Positive, negative, and indeterminant results were noted in nine (75%, p < 0.001), two, and one patient(s), respectively.

CONCLUSIONS

The neurolytic technique, although far from being considered a routine procedure, appears to provide patients with safe and effective pain relief for pain unresponsive to conventional medical treatment.

Molecular approaches to cancer immunotherapy

The use of cytokines and costimulatory molecule gene-engineered tumor cells to enhance tumor immunogenicity and elicit curative responses against established tumors and tumor recurrences has become an attractive prospect. The immunotherapy data obtained in many experimental tumor systems using these engineered cells are reviewed here to provide a realistic assessment of the potential and limits of this technique.

[Evaluation of total and inflated lung volumes by a quantitative study using computerized tomography in patients with acute noncardiogenic pulmonary edema (ARDS)]

Our study was aimed at developing a method to assess lung volumes and relative percentages of well-inflated lung parenchyma in Adult Respiratory Distress Syndrome (ARDS) patients by processing conventional CT examinations of the lung and at investigating the prognostic value of CT findings. Fourteen patients (5 women and 9 men, age range: 35-79 years) admitted to the intensive care unit January, 1992, to June, 1994, because of severe ARDS, and with lung injury scores exceeding 2.5, were submitted to CT. A homologous group of 14 patients matched for sex and age and with normal lungs was examined as a control group to investigate the accuracy of our method. Two examinations were obtained in 7 of 14 ARDS patients; the trend of lung volumes and of the relative rates of well-inflated parenchyma could thus be calculated. During the examination, we maintained in all ARDS patients the same ventilatory pattern used in the intensive care unit. Consequently, in 18/21 examinations scans and respiratory phases were not correlated. In the control group no statistically significant differences were observed between the scans obtained with (inspiratory apnea) and without coordination with the respiratory phase. As for lung volumes, our results in normal subjects showed a good correlation with normal spirometric data. In ARDS patients lung volumes, although reduced, did not correlate with prognosis. As for the percentage of well-inflated parenchyma in ARDS patients, we observed a good correlation with prognosis in the patients submitted to two examinations and, in all patients, a good correlation with D(A-a)O2 index (p < 0.05), PaO2/FiO2 index (p < 0.005) and with the rate of arteriovenous shunt (p < 0.001). In conclusion, our results show that CT of the lung is a reliable and repeatable method for the functional assessment of the lung in ARDS patients.

Evolution of endotoxin induced acute lung injury in the rat

To clarify the evolution of acute lung injury induced by endotoxin, the progression of lung damage in 26 rats submitted to intratracheal instillation of 5 mg/kg body weight endotoxin was examined by blood gas analysis, computerized tomography, light and electron microscopy. Hypoxaemia, hypercapnia, acidosis and inhomogeneous bilateral infiltrates developed gradually within 48 hours. Monocytes appeared within blood capillaries and the instertitium by 12 hours after treatment, then migrated into alveoli and underwent progressive differentiation into macrophages by 24 hours after treatment. Granulocytes were found within blood capillaries at an early stage, but outside capillaries only at 48 hours. Hyperplasia of type II pneumocytes and hypertrophy of interstitial fibroblasts also occurred at 48 hours. These data suggest that the pathogenesis of endotoxin induced pulmonary injury proceeds through an early phase of granulocyte migration inside capillaries and monocyte extravasation, an intermediate phase of monocyte differentiation into macrophages inside alveoli and a late phase of diffuse infiltration of alveoli by newly differentiated macrophages and late-extravasated neutrophils.

Local release of IL-10 by transfected mouse mammary adenocarcinoma cells does not suppress but enhances antitumor reaction and elicits a strong cytotoxic lymphocyte and antibody-dependent immune memory

The cDNA coding for mouse IL-10 (mIL-10) was transduced into the parental cells of a spontaneous adenocarcinoma of BALB/c mice (TSA-pc), and clones secreting small, medium, and large quantities of IL-10 were selected. In vivo, both low and high producer clones do not display an enhanced ability to grow in H-2 and non-H-2 incompatible mice. Instead, the intensity of their rejection increases in function of the amount of mIL-10 released. After an initial growth period in syngeneic mice, high producer clones undergo complete rejection due to the combined action of CD8+ lymphocytes, NK cells, and neutrophils. After this rejection, mice are immune to a subsequent challenge with TSA-pc. This memory rests on a strong lytic activity of CD8+ CTL and granulocytes. Following the rejection, mice also develop anti-TSA Ab that guide the granulocytes in TSA-pc memory reaction. A direct comparison shows that although TSA clones engineered to release IL-2 activate CTL and no anti-TSA Ab, those engineered to release IL-4 activate a strong Ab response but not CTL. The kind of cytokine released by the tumors appears to determine the type of response. However, IL-10 high producer cells do not deviate the immune memory, neither toward a Th1 nor a Th2. Both the CTL activity and the Ab responses induced by IL-10 high producer cells are the strongest so far observed in the TSA system.

Local release of IL-10 by transfected mouse mammary adenocarcinoma cells does not suppress but enhances antitumor reaction and elicits a strong cytotoxic lymphocyte and antibody-dependent immune memory

The cDNA coding for mouse IL-10 (mIL-10) was transduced into the parental cells of a spontaneous adenocarcinoma of BALB/c mice (TSA-pc), and clones secreting small, medium, and large quantities of IL-10 were selected. In vivo, both low and high producer clones do not display an enhanced ability to grow in H-2 and non-H-2 incompatible mice. Instead, the intensity of their rejection increases in function of the amount of mIL-10 released. After an initial growth period in syngeneic mice, high producer clones undergo complete rejection due to the combined action of CD8+ lymphocytes, NK cells, and neutrophils. After this rejection, mice are immune to a subsequent challenge with TSA-pc. This memory rests on a strong lytic activity of CD8+ CTL and granulocytes. Following the rejection, mice also develop anti-TSA Ab that guide the granulocytes in TSA-pc memory reaction. A direct comparison shows that although TSA clones engineered to release IL-2 activate CTL and no anti-TSA Ab, those engineered to release IL-4 activate a strong Ab response but not CTL. The kind of cytokine released by the tumors appears to determine the type of response. However, IL-10 high producer cells do not deviate the immune memory, neither toward a Th1 nor a Th2. Both the CTL activity and the Ab responses induced by IL-10 high producer cells are the strongest so far observed in the TSA system.

5-Fluorocytosine-induced eradication of murine adenocarcinomas engineered to express the cytosine deaminase suicide gene requires host immune competence and leaves an efficient memory

The nonmammalian cytosine deaminase (CD) enzyme converts the nontoxic prodrug 5-fluorocytosine (5-FC) to the toxic metabolite 5-fluorouracil. Parental cells of a mammary adenocarcinoma (TSA-pc) of BALB/c mice were transfected with the CD gene (TSA-CD), and the ability of 5-FC to hamper their growth was evaluated. A quantity amounting to 0.5 mg of 5-FC/0.3 ml of medium inhibits the proliferation of TSA-CD cells, but not that of TSA-pc, nor that of TSA-pc transfected with neomycin-resistance gene only (TSA-neo). In BALB/c mice, 800 mg 5-FC/kg of body weight injected daily i.p. for 30 days causes total regression of incipient (1-day-old), and established (3- and 7-day-old) TSA-CD tumors, and of 3-day-old experimental lung metastases, but does not impair TSA-pc nor TSA-neo cell growth. Because in CD8+ T lymphocyte- and granulocyte-depleted mice 5-FC no longer impairs TSA-CD growth, immune mechanisms appear to play an important role in this regression. Following, regression, all mice are resistant to subsequent s.c. or i.v. lethal challenges with TSA-pc. The induction of this immune memory is dependent on CD4+ lymphocytes, whereas its effector phase depends on both CD4+ and CD8+ lymphocytes. The memory elicited in tumor-bearing mice by the 5-FC-dependent regression of TSA-CD tumors cures a significant number of mice with 4-day-old TSA-pc metastases, but does not impair the growth of 4-day-old solid s.c. tumors. The reliability of this regression and the subsequent establishment of an efficient immune memory against poorly immunogenic TSA-pc offer the prospect that CD-transduced tumor cells and 5-FC can be used as components of a live antitumor vaccine.

5-Fluorocytosine-induced eradication of murine adenocarcinomas engineered to express the cytosine deaminase suicide gene requires host immune competence and leaves an efficient memory

The nonmammalian cytosine deaminase (CD) enzyme converts the nontoxic prodrug 5-fluorocytosine (5-FC) to the toxic metabolite 5-fluorouracil. Parental cells of a mammary adenocarcinoma (TSA-pc) of BALB/c mice were transfected with the CD gene (TSA-CD), and the ability of 5-FC to hamper their growth was evaluated. A quantity amounting to 0.5 mg of 5-FC/0.3 ml of medium inhibits the proliferation of TSA-CD cells, but not that of TSA-pc, nor that of TSA-pc transfected with neomycin-resistance gene only (TSA-neo). In BALB/c mice, 800 mg 5-FC/kg of body weight injected daily i.p. for 30 days causes total regression of incipient (1-day-old), and established (3- and 7-day-old) TSA-CD tumors, and of 3-day-old experimental lung metastases, but does not impair TSA-pc nor TSA-neo cell growth. Because in CD8+ T lymphocyte- and granulocyte-depleted mice 5-FC no longer impairs TSA-CD growth, immune mechanisms appear to play an important role in this regression. Following, regression, all mice are resistant to subsequent s.c. or i.v. lethal challenges with TSA-pc. The induction of this immune memory is dependent on CD4+ lymphocytes, whereas its effector phase depends on both CD4+ and CD8+ lymphocytes. The memory elicited in tumor-bearing mice by the 5-FC-dependent regression of TSA-CD tumors cures a significant number of mice with 4-day-old TSA-pc metastases, but does not impair the growth of 4-day-old solid s.c. tumors. The reliability of this regression and the subsequent establishment of an efficient immune memory against poorly immunogenic TSA-pc offer the prospect that CD-transduced tumor cells and 5-FC can be used as components of a live antitumor vaccine.

Immunizing and curative potential of replicating and nonreplicating murine mammary adenocarcinoma cells engineered with interleukin (IL)-2, IL-4, IL-6, IL-7, IL-10, tumor necrosis factor alpha, granulocyte-macrophage colony-stimulating factor, and gamma-interferon gene or admixed with conventional adjuvants

To evaluate the efficacy of vaccinations with cytokine-gene-transduced tumor cells, BALB/c mice were challenged with 1 x 10(5) parental cells of a syngeneic adenocarcinoma cell line (TSA-pc). No protection was observed in mice immunized 30 days earlier with 1 x 10(5) nonreplicating mitomycin-C-treated TSA-pc alone, or with Corynebacterium parvum or Complete Freund Adjuvant (CFA). Ten to 30% of mice immunized with nonreplicating cells engineered to produce interleukin (IL)-2, IL-4, IL-6, IL-7, IL-10, tumor necrosis factor alpha, granulocyte-macrophage colony-stimulating factor, and gamma-interferon gene were protected. Fifty % of mice immunized with replicating TSA-pc admixed with C. parvum and 80-100% of mice immunized with replicating tumor cells transduced with IL-2, IL-4, IL-7, IL-10, or gamma-interferon gene were protected. No cure was afforded by TSA cells admixed with C. parvum or CFA, nor by TSA cells engineered with IL-6, granulocyte-macrophage colony-stimulating factor, and tumor necrosis factor alpha gene injected starting 1 day after TSA-pc challenge. Complete tumor regression, however, was obtained in 10-20% of mice treated with TSA cells transduced with IL-2, IL-4, IL-7, or IL-10 and in 30% of those treated with TSA cells transduced with gamma-interferon gene.

[Expired ethane as a non-invasive marker of the course of experimental multiple organ dysfunction syndrome (MODS)]

BACKGROUND AND WORK HYPOTHESIS: The mechanisms of organ damage in MODS are unclear. Given that lipid peroxidation induced by oxygen radicals may play a key role in organ damage, expired ethane, a marker of lipid peroxidation, could be correlated to the entity and evolution of experimental MODS.

STUDY DESIGN AND METHODS

Forty wistar male rats (250 +/- 15 g body weight) were intraperitoneally injected with 10 ml of Zymosan mineral oil suspension (2.5%) to provoke MODS. Survival and symptoms were noted daily. On the 2nd, 7th and 14th day the animals underwent thorax CT scanning. CT images were processed to evaluate the relative density of lung parenchima. Expired ethane was measured using mass spectrometer and percentual changes were noted. Relative organ weight (liver and lung) were measured in 2nd, 7th and 14th day.

STATISTICAL ANALYSIS

Pearson's linear correlation.

RESULTS

The results show that maximal lung damage took place at the same moments as ethane concentrations peaked. A strict correlation (r = 0.93; p < 0.0001) was found between lung density and expired ethane. Strict correlation was found between organ weight, symptoms, survival and ethane production.

CONCLUSIONS

Lipid peroxidation, as expressed by ethane production, might be an important cause of organ damage in MODS.

[Evaluation of an experimental model of multiple organ dysfunction]

OBJECTIVE

To perform an experimental model of Multiple Organ Dysfunction Syndrome (MODS) without employing bacteria or endotoxin stimulus and to follow its evolution in vivo by a Computerized Tomography analysis of the lungs.

DESIGN

Rats were submitted to intraperitoneal injection of a 2.5% zymosan suspension in mineral oil (1 g/kg weight) or mineral oil alone; control rats received no treatment.

METHODS

The observation period was 15 days. During this period symptoms and survival were noticed daily. CT scans of lungs were made at the 7th and 14th days; data were post-processed to obtain information on lung density. The rats were sacrificed at the 15th day by heart puncture; blood was utilized for determination of hemochrome, differential leukocyte count, thrombocytes, glycemia, uremia, bilirubin. Lungs, liver, spleen and kidney were dissected and weighted for determination of relative organ weight.

DATA ANALYSIS

Data were compared by "t" Student's test for impaired data and Fisher Exact test.

RESULTS

Symptoms, survival, blood analysis and relative organ weight agreed with a progressive, ingravescent, triphasic illness caused by a systemic inflammatory response involving remote organ too. The CT study proved able to monitoring and analyzing organ damage: a temporal sequence of evolution of damage exists; organ damage is localized in microcirculatory system (density augment) and in parenchyma (morphologic alterations and fibrosis).

DISCUSSION

The described experimental model reproduces a MODS-like illness in zymosan receiving rats; the CT scan is effective to evaluate the evolution of organ damage.

Cytokine-induced tumor immunogenicity: from exogenous cytokines to gene therapy

The local presence of cytokines can drastically alter tumor host immune relations and activate a nonspecific reaction that in some cases leads to induction of specific responses to otherwise nonimmunogenic tumors. The employment of cytokines in the creation of new antitumor vaccines is thus a tempting prospect. Analogous effects have been obtained with cytokines inoculated locally and cytokines released from tumor cells engineered to produce them. An account is given of some mechanisms whereby this cytokine-induced reaction results in increased tumor immunogenicity. However, the real value of this potential form of vaccine in inducing the regression of incipient or established tumors remains to be established.

[CT-guided thoracic biopsy. Personal experience with DBNH Haaga 20 G needles]

CT-guided fine-needle biopsy of the chest is nowadays a conventional diagnostic procedure, which can be furtherly improved so as to increase its diagnostic sensitivity and to reduce complications. We studied a series of possible improvements over a 2-year period (1990-1992). In our radiology department 164 CT-guided biopsies were performed in 130 men and 34 women. DBNH Haaga 20-G (15 cm) needles (Cook, Denmark) were used. This kind of needle is a coaxial cutting-edge needle used for simultaneous cytological and histological sampling. Exams were performed with a Philip Tomoscanner CX-S (scanning time: 2.8 seconds). Of 164 tissue samples, 153 (93.4%) were adequate for histological diagnosis. As for suspected neoplastic disease, our results demonstrated 108 true positives, 27 true negatives, 18 false negatives and no false positive. Sensitivity, specificity and diagnostic accuracy were 85.7%, 100% and 88.2%, respectively. In 24 cases there were minor complications--i.e., 5 cases of parenchymal hemorrhage and 19 cases of minor pneumothorax. In one case only there was major pneumothorax which required surgical drainage. On the basis of our experience, we suggest the use of such coaxial catheters as the DBNH Haaga type for the collection of both histological and cytological material because this needle reduces the need for repeated invasive and potentially dangerous maneuvers.

Conflicting aspects of renal leiomyoma with different imaging techniques

A case with benign renal leiomyoma examined by all the imaging techniques currently available is described. The aspects were conflicting, particularly with regard to sonography and magnetic resonance imaging, and the sole technique which provided more reliable information was the CT scan.

[Preoperative staging of rectal carcinoma by transrectal echography combined with pelvic computerized tomography]

The accurate staging of rectal carcinoma is very important for treatment planning. The histological data obtained from the surgical specimens of 22 patients with rectal carcinoma were compared with pre- and postoperative endorectal US findings and with preoperative CT results. According to an adapted version of the Astler and Coller classification, the different degrees of tumor spread into the rectal wall were represented as follows: stage A: 1 patient; stage B1: 5 patients; stage B2: 6 patients; stage C1: 1 patient; stage C2: 8 patients and stage D: 1 patient. Preoperative staging, based on the overall results of CT and US, was in agreement with histology in 19 of 22 cases. Individual analysis of US and CT results, in comparison with histological data, showed US staging accuracy to be 77.3% (17/22 patients). US accuracy in demonstrating tumor spread into the rectal wall (stages A, B1, C1) was 100% (7/7 patients); US was 70% accurate in lymph node detection (7/10 patients) and 93.3% accurate in demonstrating perirectal infiltration (14/15 patients). CT diagnostic accuracy was 66.7% (10/15 patients) in the evaluation of perirectal lymph nodes, but tumor spread into the rectal wall (stages A and B1) could not be evaluated. While admitting the primary role of US in the staging of rectal carcinoma, according to our results a combination of US and CT yields a more accurate preoperative diagnostic picture.

Sacrococcygeal chordoma: clinicoradiological study

A case of sacrococcygeal chordoma is presented. We review the literature and we discuss the problems related to the etiology, the symptoms, the diagnosis and the treatment of this rare neoplasm. We present and discuss here the importance and the different possibilities of new diagnostic techniques, such as the CT and the MRI in the diagnosis and management of sacrococcygeal chordoma.