Effects of gamma knife radiosurgery for brain tumors: clinical evaluation

BACKGROUND: Gamma knife radiosurgery is a safe and effective alternative to microsurgery in the management of selected intracranial lesions. In our initial three-year experience with gamma knife radiosurgery, 431 patients were treated using this method. This report presents the treatment results for three different types of brain tumors: benign meningiomas, malignant metastases and gliomas. METHODS: A retrospective study was performed to analyze a consecutive series of 71 meningiomas, 31 metastatic tumors and 21 gliomas treated by gamma knife radiosurgery between March 1993 and May 1996. The treatment results were investigated using regular magnetic resonance examinations and tumor volume measurement at six-month intervals to observe sequential changes of the tumors. Patients with meningiomas were further divided into three groups according to the peripheral radiation doses: high-dose (20-17 Gy, n = 18), medium-dose (16-15 Gy, n = 33) and low-dose (14-12 Gy, n = 20). The Generalized Estimation Equation was applied to compare treatment results in these three groups with different doses and tumor volumes. RESULTS: Volume measurements of the 71 meningiomas showed that 76% decreased in size, 16% stabilized and 8% increased in size. The volumes increased most frequently in the early stage (6-12 months) after treatment and subsequently regressed after the twelfth month. The tumor control rate for meningiomas in our three-year follow-up was over 90%. For meningiomas, the statistical analysis showed that both the radiation dose and tumor volume were significantly related to the development of adverse radiation effects (p < 0.05). In metastatic tumors, rapid tumor regression after radiosurgery was found in 87% of the patients. In gliomas, radiosurgery effectively inhibited tumor growth in selected patients with small, circumscribed, less infiltrative tumors. Ependymomas and low-grade astrocytomas had more favorable outcomes than other gliomas. CONCLUSIONS: Gamma knife radiosurgery is effective for controlling tumor growth in benign meningiomas for up to three years after surgery. In selected cases of malignant metastasis and gliomas, most patients appeared to benefit from the treatment with symptomatic improvement and prolonged survival. Treatment strategy and dose selection in radiosurgery should be adjusted to optimize tumor control and avoid adverse radiation effects.     

Tumor imaging with a macromolecular paramagnetic contrast agent: gadopentetate dimeglumine-polylysine

RATIONALE AND OBJECTIVES: We evaluated magnetic resonance (MR) contrast enhancement of tumor tissue following injection of the macromolecular conjugate, gadopentetate dimeglumine-polylysine. METHODS: T1-weighted MR imaging scans were performed on female Fisher-344 rats with subcutaneously implanted mammary adenocarcinoma tumors. Following the baseline scan, gadopentetate dimeglumine-polylysine or gadopentetate dimeglumine was injected at a dose of 0.1 mmol gadolinium per kilogram. RESULTS: Gadopentetate dimeglumine-polylysine injection resulted in a maximum enhancement of tumor contrast of 310 +/- 60% (n = 7). Tumor tissue remained enhanced and well defined for several days after gadopentetate dimeglumine-polylysine injection. Gadopentetate dimeglumine injection at the same dose resulted in a 70 +/- 25% (n = 4) maximal tumor enhancement and a corresponding 25 +/- 4% muscle enhancement. CONCLUSION: Gadopentetate dimeglumine-polylysine provides higher, more sustained tumor contrast than does gadopentetate dimeglumine for the same dosage of gadolinium.     

Rare intracranial plasmacytoma manifestations. Case reports and review of the literature in diffuse plasmocytoma, in primary solitary extramedullary plasmacytoma in in primary solitary osseous plasmacytoma

Plasmacytomas can be divided into multiple, solitary osseous and solitary extraosseous/extramedullary plasmacytomas. Intracranial plasmacytomas of the dura, leptomeninx and cerebrum are well known from the literature. They are manifestations of multiple myeloma, intracranial extramedullary plasmacytoma or metastatic disease of extramedullary plasmacytoma in distant locations. We describe a cerebellar manifestation of a solitary plasmacytoma of the bone, and a leptomeningeal carcinomatosis of a multiple plasmacytoma. A summary of the literature concerning intracranial plasmacytomas is given. Dural manifestations of plasmacytoma have the same features as meningiomas in CT or MRI. Cerebral or cerebellar manifestations cannot be differentiated from brain tumors by means of CT or MRI. In CT, plasmacytomas show high-density lesions. T2w-MRI reveals a low-intensity lesion. In T1w-MRI, intense homogeneous contrast enhancement can be demonstrated.     

Growth kinetics and treatment response of the intracerebral rat 9L brain tumor model: a quantitative in vivo study using magnetic resonance imaging

We report the use of magnetic resonance imaging (MRI) for in situ tumor growth rate studies of experimental intracranial 9L tumors. T2-weighted spin-echo coronal magnetic resonance images of rat brains with 9L tumors were obtained every 2 days beginning at 8-11 days postimplantation using a 7 tesla MRI system. Tumors were clearly delineated in the images as a hyperintense region with a relatively well-demarcated border and minimal peritumoral edema. Tumor volumes from individual slices were summed together to yield the total tumor volume. The accuracy of this methodology for volumetric determination was verified by MRI phantom studies. Tumor growth rates determined from sequential MRI measurements of tumor volumes were quantitated in terms of volumetric doubling time. Tumor doubling times were found to range from 50 to 81 h, with an average of 66 +/- 8 h (n = 10). Intracranial 9L tumors were found to grow exponentially over the entire life span of the animal, allowing treated animals to serve as their own controls since the volumetric doubling time could be determined from three to four MRI scans before treatment administration. The intracerebral tumor growth delay following a single injection of 1, 3-bis(2-chloroethyl)-1-nitrosourea (13.3 mg/kg i.p.) allowed for noninvasive determination of in vivo log cell kill. A 2.0 +/- 0.2 (n = 3) log cell kill from 1,3-bis(2-chloroethyl)-1-nitrosourea treatment was found from post-treatment MRI volume measurements. These results demonstrate that MRI provides a powerful and sensitive method for assessing the growth and treatment response of intracranial 9L tumors in the rat.     

Cystic meningiomas resembling glial tumors

BACKGROUND: Meningiomas can be associated with peripheral or intratumoral cysts. Meningiomas with intratumoral cysts, also called "true cystic" meningiomas, are rare and can frequently be confused with glial or metastatic tumors. METHODS: We report three cases of "true cystic" meningiomas and discuss the preoperative evaluation, etiology, and surgical treatment of these cystic lesions with reference to the literature. RESULTS: Magnetic resonance imaging (MRI) and computed tomography (CT) studies usually display a cystic lesion close to the dura with or without enhancement of the cyst wall. Multiplanar MRI scans are very useful to show the presence of a solid tumor or some dural enhancement. Some cases of "true cystic" meningiomas however, are still erroneously preoperatively diagnosed. Complete surgical removal of the tumors and of the entire cyst wall was performed in our cases. Despite the absence of a typical ring enhancement of the cystic lesion in two cases, histopathologic studies displayed the presence of tumor cells on the cyst wall of both cases. CONCLUSIONS: Tumor cells can be present on the cyst wall and therefore can be one of the causes of tumor recurrence if not totally removed. Accurate preoperative radiologic diagnosis (multiplanar MR images) and intraoperative histopathologic studies are fundamental in that they will definitely influence the surgical strategy and outcome.     

Meningiomas. Epidemiological and anatomopathological study of 340 cases

The authors have retrospectively reviewed all tumors of central nervous system (CNS) operated at the most important neurosurgery hospitals of Curitiba in a 5-year period (1990-1994) and found 304 (22.4%) cases of meningioma. Age mean of the patients was 48.5 years, with a range of 3 to 90 years. A marked female preponderance (68.7%) was noted. The most common tumor location was brain (n = 280) and the remaining cases occurred in spinal cord (n = 10), cerebellum (n = 9) and cranial nerves (n = 5). Histologically, there were 294 (96.7%) meningiomas of the classical type, six malignant or anaplastic, three atypical and one papillary. Two hundred and sixty seven classical meningiomas were from the meningotelial subtype, ten psamomatousos, five fibroblastic, five microcystic, five transicional and two angiomatous. The authors conclude that meningiomas are one of the most common group of primary neoplasias of CNS and the definition of malignancy in those tumors is beset by frequent discordance between histologic and biologic features.     

Chromosomal losses and gains in meningiomas: comparative genomic hybridization (CGH) study of the whole genome

We investigated chromosomal aberrations in meningiomas using newly developed comparative genomic hybridization (CGH) technique and compared the results with the proliferating potential of the tumors. This technique permits the entire genome to be surveyed in one session of experiments. Our results revealed chromosomal aberrations in 5 out of 10 (50%) of the tumor samples studied. Losses of the distal parts of chromosome 1p (5 out of 10) and 22q (3 out of 10) were the two most frequent chromosomal aberrations. Losses and/or gains in other regions were only sporadic. The MIB-1 staining indices (MIB-SI, %) were 1.9 +/- 0.9% (mean +/- SD) in benign (n = 8), 4.5% in atypical (n = 1), and 11.7% in anaplastic (n = 1) meningiomas. The comparison of MIB-SI between the tumors with (2.3 +/- 0.6%) and without (1.6 +/- 0.3%) chromosomal aberrations demonstrated a trend towards an increased MIB-SI in meningiomas with chromosomal aberrations (p < 0.07) by unpaired Student's t-test. This study suggests that alterations in chromosomes 1p and 22q could be a primary focus of further detailed assessment of tumorigenesis and in understanding the biological behavior of meningiomas.     

Appearance of the resection area of brain tumors in intraoperative MRI imaging

During MRI-controlled resection of brain tumors using an open MRI system, operation-induced alterations may occur, especially enhancement of the resection cavity wall. This may simulate tumor areas, resulting in false assessment of the resection or resection of non-tumorous areas. Based on 42 MRI- and biopsy-controlled brain tumor resections in an 0.5 T open MRI (Signa SP, GE), the appearance and origin of operation-induced reactions are analyzed. In our opinion, there is a superposition of preformed peritumoral reactions by operation-induced microcontusions. The beginning of the cavity wall enhancement needs at least 10-15 min. MRI-controlled analysis of the intraoperative steps by the neurosurgeon and neuroradiologist allows discrimination of operation-induced reactions from tumor areas and leads to safe operation.     

Importance in France of the infestation by Dirofilaria (Nochtiella) repens in dogs

INTRODUCTION: This review was performed to evaluate the outcome of patients undergoing pancreaticoduodenectomy (PD) for isolated metastatic or locally advanced nonperiampullary tumors at a single institution over a 13-year period. METHODS: Between 1983 and 1996, patients undergoing PD for metastatic or locally advanced nonperiampullary malignancies were identified. Medical records were reviewed and outcome factors and survival data analyzed. RESULTS: Eighteen patients were identified. The primary tumor histopathology included colon (n = 7), gastric (n = 4), renal cell (n = 3), lung (n = 2), bladder (n = 1), and melanoma (n = 1). The median length of hospital stay was 15 days (6 to 48) with one perioperative death (5.5%). The median tumor size was 5.5 cm (0.8 to 11.5), and 7 patients had positive peripancreatic lymph nodes. The median survival was 40 months, with a 5-year survival of 35%. CONCLUSIONS: Pancreaticoduodenectomy for nonperiampullary malignancy is infrequently indicated. However, in the absence of widely metastatic disease, PD should be considered for locally advanced tumors or isolated metastatic malignancy.     

Atypical squamous cell carcinoma of the larynx and hypopharynx: radiologic features and pathologic correlation

The objective of this study was to analyze the radiologic features of atypical forms of squamous cell cancer and correlate them with clinical, endoscopic, and histopathologic findings. The CT and MRI images of 31 patients with atypical forms of squamous cell carcinoma were reviewed retrospectively and the radiologic findings were correlated with clinical, endoscopic, and histopathologic findings. Histopathologic diagnoses included undifferentiated carcinoma of nasopharyngeal type (n = 8), verrucous carcinoma (n = 18), spindle cell carcinoma (n = 3), and basaloid cell carcinoma (n = 2). Undifferentiated carcinoma of nasopharyngeal type was located in the supraglottis or piriform sinus beneath an intact mucosa and initial endoscopic biopsy was most often negative. The discrepancy between an intact mucosa at endoscopy and a solid mass with homogenous enhancement at CT or MRI was characteristic for these tumors and warranted further investigations to obtain the definitive histologic diagnosis. Verrucous carcinoma displayed characteristic clinical, radiologic, and pathologic features, namely, an exophytic tumor arising from the glottic level displaying a rugged surface with finger-like projections but with only minor submucosal infiltration. Spindle cell carcinoma appeared as a polypoid mass with a thin stalk arising from the supraglottis. Basaloid cell carcinoma displayed a distinct lobulated enhancement pattern which was observed on contrast-enhanced T1-weighted SE images. Although the MR and CT features of atypical forms of squamous cell carcinoma cannot be considered pathognomonic they should raise the differential diagnosis even if endoscopic biopsy has been negative. The radiologist's awareness of the appearance of these unusual tumors on CT and MR images may greatly facilitate the diagnostic work-up and helps to guide the endoscopist to the adequate biopsy site in order to establish the correct diagnosis.     

Port-site recurrences following laparoscopic operations for gynaecological malignancies

OBJECTIVE: To determine the frequency of port-site recurrences following laparoscopic surgical treatment of gynaecological malignancies metastatic at the time of surgery. DESIGN: Retrospective review of metastatic primary and recurrent gynaecological malignancies. RESULTS: Twenty-five women were studied. Twenty-four had metastatic disease at the time of laparoscopic surgery, 22 in association with a primary malignancy (cervix: n = 12, ovary: n = 7, endometrium: n = 3), and two in association with recurrent ovarian cancer; all received pelvic or extended field radiation or chemotherapy after surgery. One woman with Stage IIIC ovarian cancer, disease-free at the completion of neoadjuvant chemotherapy following laparotomy by a general surgeon, was included; she developed scalene node metastases 18 months after definitive laparoscopic surgery. Seventy-one 5 mm trocars and fifty 10 mm trocars (total n = 121) were used for surgery; thirty-one 10 mm trocar sites and forty-four 5 mm sites (total n = 75) received post-operative treatment with chemotherapy (n = 49) or radiation (n = 26). Four women (16%) developed recurrences in association with endometrial (n = 2) and cervical (n = 2) cancer at six trocar sites. All recurrences were associated with abdominopelvic and/or distant metastases, and all occurred at untreated 5 mm trocar sites. The difference in recurrence rates between 5 mm and 10 mm trocar sites (chi(2) = 6; P < 0.025), and between treated and untreated trocars (chi(2) = 5; P < 0.05) were both statistically significant (McNemar's test), but the effects of treatment and trocar size on the port-site recurrence rate were confounded. CONCLUSIONS: Port-site recurrences are local manifestations of disseminated disease that result from the enhancement of tumour growth characteristic of healing tissues and can be prevented by appropriate post-operative therapy.     

MIB-1 labeling indices in benign, aggressive, and malignant meningiomas: a study of 90 tumors

Predicting tumor behavior in meningiomas based on histology alone has been problematic. This study retrospectively compares histology and MIB-1 (cell proliferation marker) labeling indices (LI) in benign, aggressive, and malignant meningiomas. Six histological features, including mitoses, necrosis, loss of pattern, hypervascularity/hemosiderin deposition, prominent nucleoli, and nuclear pleomorphism, were compared in 90 meningiomas (Fisher's exact test). Tumors with two or more of the above features were designated as aggressive meningiomas. Malignant meningiomas were characterized by brain invasion or metastasis. The MIB-1 LIs (% positive tumor cell nuclei) were compared between the three groups (Kruskal-Wallis test, Wilcoxon two-sample test). Of the benign meningiomas (n=37; mean age, 54 years), 41% had one of the six histological features, with nuclear pleomorphism (n=10) being the most frequent. The aggressive tumors (n=29; mean age, 61 years) were characterized by nuclear pleomorphism (n=28), mitoses (n=20), necrosis (n=16), loss of pattern (n=16), prominent nucleoli (n=6), and hypervascularity/hemosiderin deposition (n=5). Malignant tumors (n=24; mean age, 59 years) were characterized by nuclear pleomorphism (n=22), mitoses (n=21), loss of pattern (n=21), necrosis (n=21), nucleoli (n=17), and hypervascularity/hemosiderin deposition (n=3). Significant differences were found between the aggressive and malignant groups with regard to loss of pattern, necrosis, and nucleoli (P=.0043, .011, and .00029, respectively). Mean MIB-1 LIs for the benign, aggressive, and malignant groups were 1.0% (range, 0 to 5.5%),5.5% (range, 0.1 to 32.5%), and 12.0% (range, 0.3 to 32.5%), respectively. Differences in the mean MIB-1 LI between groups were statistically significant, with P values of <.0001 (benign v aggressive) and .0012 (aggressive v malignant). Mean MIB-1 LIs for recurrent versus nonrecurrent tumors were 7.1% (range, 0 to 32.5%) versus 3.8% (range, 0 to 20.9%) (P=.32). The mean MIB-1 LI for patients who were alive with or without tumor was 6.2% (range, 0 to 32.5%) versus a mean MIB-1 LI of 14.2% (range, 2.8% to 32.5%) for patients who died of or with tumor (P=.0013). In conclusion, (1) There is a statistically significant difference in the increasing MIB-1 LI means between benign, aggressive, and malignant meningiomas and between patients who were alive versus those who died; (2) there is some overlap in MIB-1 LI ranges between groups, which warrants caution in interpreting an individual MIB-1 LI in a given tumor.     

Cervicothoracic tumors: results of resection by the "hemi-clamshell" approach

OBJECTIVES: Our goal was to describe the "hemi-clamshell" approach for the resection of primary and metastatic tumors of the cervicothoracic junction, evaluate its morbidity and mortality, and present survival data on a series of 42 patients who underwent resection with the use of this technique. METHODS: We conducted a retrospective review of the records of all patients of a single surgeon undergoing resection of tumors of the cervicothoracic junction. Data collected includes tumor type and involvement, type of resection, complications, and survival. RESULTS: Forty-two patients underwent resection of various primary (n = 28) and metastatic (n = 14) tumors of the cervicothoracic junction over 6.5 years by means of the hemi-clamshell approach. En bloc resection of the tumor and invaded structures was successful in all but two patients (5%), who required an additional posterolateral thoracotomy to facilitate removal of tumor invading the posterior chest wall. Invaded structures that were resected included lung (n = 22), vertebral body (n = 7), chest wall (n = 8), central veins (n = 10), thyroid (n = 3), carotid artery (n = 1), and cervical esophagus (n = 1). Four major complications occurred in three patients, and nine minor complications occurred in eight patients. There were no deaths. The overall 5-year actuarial survival was 67.4%. CONCLUSIONS: Tumors of the cervicothoracic junction are represented by a variety of histologic types and can be both primary and metastatic. The hemi-clamshell approach is a successful technique for the exposure and resection of these tumors. This approach has significant advantages over other previously reported techniques. The complication rate is low and the mortality rate is zero in this series, the largest yet reported. Long-term survival is acceptable if complete resection can be performed.     

Analysis of small lung nodules diagnosed by open lung or thoracoscopic biopsy

We examined clinicopathologic findings in 86 cases with peripheral lung nodules less than 30 mm in size diagnosed by open lung or video-assisted thoracoscopic surgery (VATS) biopsy. Biopsies were conducted because of the new appearance or enlargement of nodules as evidenced in a comparison with retrospective chest films in 47 patients, X-ray findings of malignancy suspicion without retrospective films in 13, enlargement of nodules after the administration of antituberculosis agents in 9, and a past history of malignancy in 17. Mean tumor size was 18.1 mm in primary lung cancer (n = 29), 16.2 mm in metastatic lung cancer (n = 13), 16.3 mm in tuberculosis (n = 18), 15.3 mm in nonspecific inflammation (n = 12), 16.7 mm in benign lung tumors (n = 7), 7.5 mm in intrapulmonary lymph node (n = 2), and 19.4 mm in others (n = 5). Among primary lung cancers with a clear N-factor, the percentage of T1N0M0 cancers was up to 72%. No significant difference was observed in either of the reasons for these biopsies and the size of nodules among diseases. To detect early lung cancer and increase the rate of cure, small pulmonary nodules that could be hardly diagnosed using bronchoscopic or needle aspiration biopsy should be diagnosed positively using VATS biopsy.     

Esophagectomy for carcinoma in the octogenarian

To correlate the findings on MRI with histopathology of metastatic melanoma, MRI was performed on 29 patients with 36 lesions, using spin-echo and inversion recovery sequences. Histopathologic examination of lesions was performed within 4 weeks of imaging. Lesions were categorized according to cell type and were also evaluated for the presence and extent of melanin, iron, and necrosis. These data were then correlated with the signal intensities of the lesions. Enhancement of lesions after injection of intravenous gadolinium was calculated and correlated to vascularity of the tumor. Melanin was present more frequently in lesions appearing hyperintense or with mixed signal intensity (12/15) than in those appearing hypo- or isointense (6/21) on the T1-weighted sequence. This trend was significant (P = .013). Also, more lesions appearing mixed, ie, having both hypo- and hyperintense components, contained melanin (15/23), as opposed to lesions that appeared to be only hyperintense (3/13) on the STIR sequence. There was no clear association between signal intensity and melanin content on the T2-weighted sequence. There was no significant association between the signal intensities on the MR images and the iron content, tumor size, or tumor cell type of these lesions. There was no clear association between enhancement after gadolinium injection and vascularity, as assessed by histology. The authors concluded in this study that T1 shortening and hypointensity on the STIR sequence seen in patients with metastatic melanoma are most closely related to the melanin content of the tumor.     

Renal cell carcinoma: preoperative assessment for enucleative surgery with angiography, CT, and MRI

PURPOSE: Our purpose was to assess various imaging methods in detecting a pseudocapsule of renal cell carcinoma (RCC), which is critical for successful tumor enucleation. METHOD: In 42 patients with histopathologically proven RCC, images obtained at angiography (n = 42), CT (n = 30), and MRI (n = 19) were investigated retrospectively. All patients underwent treatment (enucleation: n = 15; nephrectomy: n = 27). The imaging criteria for the presence of a pseudocapsule were as follows: a surrounding radiolucent rim on angiography, a low or high density rim on CT, and a low intensity rim on MRI. All images were retrospectively reviewed by three radiologists without knowledge of the clinical and histological findings. RESULTS: Thirty-three of 42 RCCs showed a pseudocapsule on the surgical specimen. A pseudocapsule was detected in 67% of tumors (22/33) on angiography, 26% (6/23) on CT, 27% (4/15) on T1-weighted MRI, 93% (14/15) on T2-weighted MRI, 67% (8/12) on dynamic enhanced T1-weighted MRI, and 15% (2/13) on delayed enhanced T1-weighted MRI. CONCLUSION: T2-weighted MR images are superior for visualizing a pseudocapsule of RCC and for providing reliable selection criteria for tumor enucleation.     

Prevention and early intervention for depression in adolescence and early adult life

We present a retrospective study in order to analyze the abnormalities noted on MRI in 27 cases of myelopathy excluding tumors, explored between 1994 and 1996. The different lesions were: Multiple Sclerosis (n = 11), Spondylotic myelopathy (n = 3), Neurosarcoidosis (n = 4), CMV Myelitis (n = 1), Radiation Myelopathy (n = 1), Spinal Dural Arteriovenous Fistula (n = 1), Intramedullary Cysticercosis (n = 1), Infarct (n = 5). The exams have been made on 1.5 Tesla Magnetom Vision Siemens or GE Signa machine. All patients have had axial and sagittal views with coronal complementary study in 4 cases. Sequences were Spin echo pT1 (TR: 560, TE: 12), Fast Spin echo pT2 (TR: 3 500, TE: 99 or 128), and gradient echo pT2 (TR: 700, TE: 22, Angle: 25 degrees). Intravenous injection of Gadolinium has been made in 16 cases (0.1 mmol/kg). We have studied the presence or not of a signal abnormality in pT1 and/or in pT2, of enhancement, and its topography (cervical, thoracic, lumbar). We classified lesions in central and/or peripheral and according, to their topography in anterior, posterior or lateral type. The form has been classified in four types (nodular, triangular, "pen like", plage). Extension in transversal (superior or inferior to half medullary surface) and cranio-caudal directions (inferior to one vertebrae, between one and two vertebrae, superior to two vertebrae) has been also classified. Others intra or perimedullar and encephalic abnormalities have been noted. We analyzed the results for each pathology and underline the essential diagnosis criteria noted (low cranio-caudal and transversal extension with frequent triangular form of Multiple Sclerosis lesions, frequent suggestive abnormalities of the encephale (82%) in Multiple Sclerosis, intra and perimedullar enhancement with deformations of the surface of the spinal cord in Sarcoidosis' lesions, extended dorsolumbar "pen like" lesions with inconstant enhancement of infarcts, focal plage lesions centered on degenerative changes of the spinal canal in spondylotic myelopathy, bony lipomatous involution in front of intramedullary radiation plage lesion...) and also review the literature and confront their results to it. We insist on the difficulties in classifying myelopathy (radio-clinical terminology discordances, identical signal abnormalities frequently caused by different illness, necessity to compare to pathologic results). We propose a MRI study protocol that should interest the whole spinal cord and comport T1 weighted without and after gadolinium sequences, T2 weighted sequences (with always a gradient echo type). 2 or better 3 different plans should be made. A complementary study of the brain by MRI is often useful. Clinical study, biology, evolution, MRI and when possible pathology all are necessary to better understand myelopathy's mechanisms.     

Evaluation of the antibody response in pigs vaccinated against Streptococcus suis capsular type 2 using a double-antibody sandwich enzyme-linked immunosorbent assay

OBJECTIVE: We assessed the value of dynamic sequential three-dimensional Fourier transformation (3DFT) MRI in differentiating various types of small liver tumors. MATERIALS AND METHODS: Forty-seven patients with 65 liver masses < 3 cm in size (42 hepatocellular carcinomas, 11 hemangiomas, 12 metastatic tumors) were studied by 3DFT fast imaging with steady-state precession (FISP) MRI [TR(ms)/TE(ms)/flip angle (degree): 20/8/30]. The slab thickness was 21-35 mm, and there were seven partitions. The 3DFT-FISP MR images were obtained immediately after 0.1 mmol/kg of gadopentetate dimeglumine was administered intravenously over 2-3 s (early phase), 60 s after (late phase I), and 120 s after (late phase II). RESULTS: Eighty-six percent of small hepatocellular carcinomas showed hyperintense enhancement relative to the surrounding liver parenchyma and iso- or hypointense enhancement with or without capsular enhancement in the late phase. Eighty-two percent of small hemangiomas showed peripheral globular enhancement in the early phase and total hyperintense or peripheral enhancement in the late phases. Ninety-two percent of the small metastatic liver tumors showed doughnut-like ring enhancement in the early phase. CONCLUSION: By dynamic 3DFT-FISP MRI, we were able to accurately evaluate the hemodynamics and morphological findings of each type of small liver tumor.     

Magnetic resonance imaging of perfusion in the isolated rat heart using spin inversion of arterial water

Measurement of regional myocardial perfusion is important for the diagnosis and treatment of coronary artery disease. Currently used methods for the measurement of myocardial tissue perfusion are either invasive or not quantitative. Here, we demonstrate a technique for the measurement of myocardial perfusion using magnetic resonance imaging (MRI) with spin tagging of arterial water. In addition, it is shown that changes in perfusion can be quantitated by measuring changes in tissue T1. Perfusion images are obtained in Langendorff-perfused, isolated rat hearts for perfusion rates ranging from 5 to 22 ml/g/min. The MRI-determined perfusion rates are in excellent agreement with perfusion rates determined from measurement of bulk perfusate flow (r = 0.98). The predicted linear dependence of the measured T1 (T1app) on perfusion is also demonstrated. The ability of perfusion imaging to measure regional variations in flow is demonstrated with hearts in which perfusion defects were created by ligation of a coronary artery. These results indicate that MRI of perfusion using spin inversion of arterial water gives quantitative maps of cardiac perfusion.