Biomedical subjects
Publications and source records attributed to P Van Tassel.
Soft-tissue sarcomas of the digit are uncommon. We herein report on a patient with a de-novo subungual right thumb liposarcoma with subsequent failure in the brain. The pertinent literature and recommendations for management are presented.
PURPOSE: To describe both the common and less frequently encountered magnetic resonance (MR) imaging features of radiation therapy- and chemotherapy-induced brain injury, with particular emphasis on radiation necrosis. MATERIALS AND METHODS: A cohort of 148 adult patients underwent surgical resection of malignant brain (glial) tumors and were subsequently entered into a research protocol that consisted of accelerated radiation therapy with carboplatin followed by chemotherapy with procarbazine, lomustine, and vincristine. Patients typically underwent sequential MR imaging at 6-8-week intervals during the 1st year and at 3-6-month intervals during subsequent years. In all patients, histopathologic confirmation of lesion composition was performed by board-certified neuropathologists. RESULTS: The patients exhibited different types of MR imaging-detected abnormalities of the brain: pure radiation necrosis in 20 patients, a mixture of predominantly radiation necrosis with limited recurrent and/or residual tumor (less than 20% of resected tissue) in 16 patients, radiation necrosis of the cranial nerves and/or their pathways in two patients, radiation-induced enhancement of the white matter in 52 patients, and radiation-induced enhancement of the cortex in nine patients. CONCLUSION: The frequent diagnostic dilemma of recurrent neoplasm versus radiation necrosis is addressed in this study through a description of the varying spatial and temporal patterns of radiation necrosis at MR imaging.
Explore the source record for details and available documents.
This pilot study's aim was to determine, using magnetic resonance imaging (MRI), if and to what extent asymptomatic intracranial hemorrhage occurs in normal term neonates after uncomplicated vaginal deliveries. Eight normal, term, vaginally delivered infants and three cesarean-section deliveries used as controls underwent cranial MRI. No sedation was administered. Small subdural hematomas of the falx cerebri or tentorium cerebelli were found in half of those with an uneventful vaginal delivery. Pediatric follow-up, on average 3.9 years after the MRI study was performed, demonstrated normal growth and development. It appears that more data is needed to confirm the observation that the intracranial hemorrhages described should not be considered the etiology for neurologic abnormalities present in symptomatic neonates.
PURPOSE: To investigate the presence of small cystlike structures in the cerebral hemispheric white matter on MR images of patients with tuberous sclerosis. METHODS: The MR images of 18 consecutive patients with tuberous sclerosis were reviewed retrospectively. RESULTS: Eight of the 18 patients were found to have cystlike structures in the cerebral white matter. The signal intensity of these lesions was isointense with cerebrospinal fluid on T1-, proton density-, and T2-weighted images. Four patients were imaged with a fluid-attenuated inversion recovery sequence, which in each case also showed fluid-type signal in these areas. Three of the patients had CT for correlation, and these scans supported the diagnosis of cystic lesions. Cysts ranged in number from one to 12 per patient and were usually smaller than 1 cm. The most common location was adjacent to the occipital horn or trigone of the lateral ventricle (six of eight patients). Less frequent sites were near the frontal horns, in the corpus callosum, and in the deep white matter near the body of the lateral ventricle. Cysts in five patients were either immediately adjacent to a cortical tuber or in the center of a white matter dysplastic lesion. A cyst in one patient had septa, and none of the cysts enhanced. CONCLUSIONS: Cystlike structures in the cerebral hemispheric white matter were seen on the MR images of 44% of 18 patients with tuberous sclerosis. Whether these findings represent cystic degeneration of dysplastic tissue or are unrelated to the disease process of tuberous sclerosis is unknown. More than one pathogenesis may exist.
We report the MR imaging findings in two cases of nasolabial cysts. Demonstration of their extraosseous location with cross-sectional imaging should prevent confusion with maxillary cysts and obviate unwarranted dental or maxillary surgery.
This article reviews the gamut of cystic lesions, unrelated to neoplastic disease, that are found in the brain, subarachnoid space, and ventricles. The utility of MRI in diagnosing these entities is shown.
Progressive cerebral sinovenous occlusion in a neonate with Sturge-Weber syndrome was documented by using two-dimensional time-of-flight MR venography. There was no evidence of intraluminal thrombus on routine spin-echo images obtained either before or after the onset of seizures, despite MR venographic evidence in both studies of venous abnormalities.
PURPOSE: To present MR findings of parenchymal brain injury after accelerated fractionation radiation therapy combined with carboplatin chemotherapy in the treatment of malignant brain gliomas. METHODS: Eighty-one evaluable subjects in an ongoing treatment protocol for malignant gliomas form the patient base for this report. After surgical resection of tumors, patients underwent a course of accelerated fractionation radiation therapy to a total dose of 60 Gy. Carboplatin was infused intravenously before each radiation treatment. Precontrast and postcontrast MR scans were obtained before treatment and at 4-week intervals afterward and were analyzed retrospectively. RESULTS: Posttreatment MR imaging in 20 of the 81 patients showed development of unusual parenchymal lesions or enlarging masses needing debulking, and these patients underwent second operations. Two groups emerged: those with tumor and necrotic brain (n = 11) and those with necrosis and reactive gliosis but no definitive tumor (n = 9). Enhancing lesions in the tumor-negative group appeared later than those in the tumor-positive group, were often multiple, and were usually located several centimeters away from the tumor resection site or even contralaterally. Common locations were the corpus callosum and corticomedullary junctions. Lesions in the tumor-positive group were more often solitary and located immediately adjacent to the surgical site. Positive and negative results of positron emission tomography with fludeoxyglucose F 18 were obtained in both groups. The incidence of brain necrosis without associated tumor was 11%. CONCLUSIONS: A pattern of unusual enhancing parenchymal brain lesions was seen on MR imaging after accelerated fractionation radiation therapy and concomitant carboplatin chemotherapy. The abnormalities seem more extensive than focal necrotic lesions on enhanced CT or MR imaging after conventional radiation therapy, and they may mimic recurrent tumor.
The normal and variant anatomy of the cerebral veins and dural venous sinuses is poorly understood by many radiologists. Beginning with a discussion of cerebral venous anatomy, this review illustrates clinically pertinent anatomy of the cerebral sinovenous system. Various methods of imaging cerebral veins and dural venous sinuses are described. Techniques and pitfalls of MR venography are emphasized.
The imaging features of a variety of dural venous sinus (DVS) abnormalities are reviewed. Congenital and heritable diseases affecting the DVS, tumor-related sinus compression, and traumatic injuries of the DVS are discussed. The causes, clinical manifestations, and imaging findings in cerebral sinovenous thrombosis are described, and pertinent imaging techniques and pitfalls are illustrated. Etiologic theories about the formation of dural arteriovenous malformations are discussed and their imaging features are demonstrated.
The manifestations of infectious disease of the spine are numerous. Viruses commonly affect the spinal cord and meninges, while tuberculosis and various bacterial and fungal organisms may involve the vertebrae, intervertebral disks, epidural and paraspinal regions, the leptomeninges, and, rarely, the cord itself. Magnetic resonance imaging, with its multiplanar capability and superb contrast resolution, is definitely the modality of choice in evaluating the patient with suspected infection of the spinal column or spinal cord and its coverings. The addition of postcontrast images is often helpful in the differential diagnosis.
A 37-year-old woman with chronic myelogenous leukemia underwent allogeneic bone marrow transplantation with CD8-depleted marrow from an HLA-identical sister. On day 43 post-transplant, the patient developed a headache and became lethargic and tremulous. Magnetic resonance imaging (MRI) of the brain showed abnormal meningeal and superficial parenchymal enhancement anteriorly. The spinal fluid had an elevated protein level with normal glucose and a neutrophilic pleocytosis. At autopsy, Toxoplasma meningoencephalitis was seen. On review of the literature, headache and confusion at 1-2 months post-transplant are common presenting signs of central nervous system toxoplasmosis. The predominance of neutrophils in the spinal fluid in this patient probably reflects the meningeal component of the infection and is an unusual finding. The presentation of toxoplasmosis in marrow transplant recipients is quite pleomorphic, and a definite diagnosis is difficult to obtain antemortem. Empiric therapy with pyrimethamine and sulfadiazine should be considered for marrow transplant recipients with neurologic deficits for which there is no other apparent etiology.
Two cases of intraosseous meningioma of the calvaria with hyperostosis are presented and compared with the appearance on plain films and CT of en plaque meningioma, metastatic disease from such primary sites as prostatic cancer, and fibrous dysplasia. It is emphasized that intraosseous meningioma in the calvaria is relatively uncommon, occurring most often in the sphenoid bone (probably because of its numerous articulations). The relationship of the development of intraosseous meningioma to the entrapment of dura containing arachnoid cells is discussed in considering the cause of such lesions, and it is stressed that calvarial fractures and cranial sutures may contribute to the entrapment of arachnoidal tissue and later the formation of a meningioma.
As we move into the 1990s, the field of diagnostic imaging displays greater usefulness as a result of continued technical improvements in existing modalities and the discovery of new techniques. Magnetic resonance (MR) imaging is now, without question, the imaging modality of choice for evaluation of tumors of the brain and spine. The general availability of the MR imaging contrast agent, gadolinium diethylenetriamine penta-acetic acid (Gd-DTPA), for the last three years has greatly expanded the role of MR imaging. Progress in metabolic imaging and MR spectroscopy may offer yet greater understanding of the physiology of brain tumors and has application for the diagnosis and posttreatment follow-up of these patients. These topics will be addressed in this review, which spans the years 1989 and 1990.
Recombinant interferon beta (IFN-beta ser) has been administered by intravenous bolus injection three times weekly at a dose of 90 x 10(6) IU to 14 patients with recurrent malignant glioma in an ongoing study. The treatment period has ranged from 1 to 40 weeks. The most common adverse experiences were fever, chills, malaise, and headache. Fever, chills and headache were worse with the first two doses and were usually relieved with acetaminophen. All patients tolerated subsequent treatments without any difficulties. No neurologic or hematologic toxicities were observed. Of ten evaluable patients, five had progressive disease in 4 to 8 weeks; three had stable disease for 12 to 21 weeks; one has had a minor response for 13 weeks; and one has had a complete resolution of tumor for 150 + weeks. IFN-beta ser appears to have activity in human glioma and is well tolerated at this dosage and schedule.
Studies of twenty-five patients with loculated leptomeningeal tumor metastases diagnosed by CT and/or MR were analyzed retrospectively. Medulloblastoma was the most frequent primary tumor (8/25, 32%). Four subgroups of loculated patterns were identified. Type A included mass(es) limited to the subarachnoid space without obvious direct parenchymal infiltration; this pattern occurred in 12 patients, of whom five had associated diffuse pattern. Type B was characterized by mass(es) still predominantly in the subarachnoid space but with minor transpinal parenchymal infiltration; this pattern was found in five patients. Type C comprised subarachnoid mass(es) with marked transpinal extension mimicking parenchymal lesion; this pattern was observed in three patients. Type D consisted of subarachnoid mass(es) growing along the perineural CSF space; this pattern was noted in two patients. Additionally, two patients presented with combined A and C patterns, and one patient had a combined B and C pattern. More than half the patients (14/25, 56%) presented with a single lesion. The most frequent locations were the suprasellar cistern, ventricular walls, and lateral recesses of the fourth ventricle, Gd-DTPA-enhanced T1-weighted MR images appeared best for demonstrating the site and extent of disease. Recognition of the loculated patterns of leptomeningeal metastases, which are less common than the diffuse pattern, is important to radiologists and clinicians for correct diagnosis and proper management of patients with this disease.
Lymphoma is the second most common neoplasm of the head and neck region and should be considered in the differential diagnosis of any lesion in this region, especially if the typical factors for squamous cell carcinoma are not present. The head and neck is the second most common site for extranodal lymphoma. It can involve virtually any region, including the orbit, paranasal sinuses, Waldeyer's ring, salivary glands, or thyroid. Communication with the surgeon and pathologist is essential to prevent an incorrect or delayed diagnosis. One should consider the diagnosis of lymphoma especially when multiple, large, nonnecrotic lymph nodes are present or multiple sites of disease are identified in extranodal tissue.