Multivoxel proton MR spectroscopy and hemodynamic MR imaging of childhood brain tumors: preliminary observations

PURPOSE: To assess multivoxel proton MR spectroscopy combined with MR imaging and hemodynamic MR imaging in the evaluation of brain tumors in children and young adults. METHODS: Fifteen patients with brain tumors and 10 healthy children underwent MR imaging and MR spectroscopy on a 1.5-T system. Ten patients with tumors had both MR spectroscopy and hemodynamic MR imaging. MR spectroscopy data sets with 1 cm3 to 3.4 cm3 resolution were acquired within 8.5 minutes by using a point-resolved spectroscopic, chemical-shift imaging technique in two dimensions with volume preselection. MR imaging was performed using fast spin-echo techniques. Hemodynamic MR imaging data were acquired every 2.5 seconds at one anatomic level using a spoiled gradient-echo sequence during intravenous bolus administration of contrast material. RESULTS: Assessment with multivoxel MR spectroscopy and hemodynamic MR imaging added about 30 minutes to the total MR examination time. Normal tissue exhibited spectral peaks from biologically significant compounds such as N-acetylaspartate (NAA), choline-containing compounds (Cho), and total creatine (tCr). Twelve biopsy-proved tumors exhibited prominent Cho, reduced NAA, variable tCr, and/or lactate or lipids, and two showed increased hemodynamic parameters. Three of the tumors treated with radiation did not reveal prominent levels of Cho. Tissue necrosis had no Cho, NAA, or tCr, and reduced hemodynamics. CONCLUSIONS: Preliminary findings by MR spectroscopy combined with MR imaging and hemodynamic MR imaging suggest that regions of active tumor may be differentiated from areas of normal tissue and areas of necrosis. These findings may enable metabolic and hemodynamic characterization of childhood brain tumors as well as suggest their response to therapy.     

Characterization of Trichomonas vaginalis virus proteins in the pathogenic protozoan T. vaginalis

PURPOSE: Children who have brain tumors are at risk for a variety of treatment-related sequelae, including neuropsychological and cognitive impairment, neurologic deficits, and neuroendocrinologic disturbances. We sought to determine the value of proton MR spectroscopy in assessing brain tissue remote from the tumor site to ascertain the effects of chemotherapy and radiation treatment in these patients. METHODS: Single-voxel proton MR spectra from 70 patients (111 spectra) and 11 healthy volunteers (11 spectra) were analyzed. NAA/Cr, NAA/Cho, and Cho/Cr ratios based on peak areas were obtained from nonneoplastic regions of the frontal lobe. The relationship between MR spectroscopic ratios and treatment was determined. RESULTS: NAA-containing ratios were decreased in patients as compared with control subjects. The presence of gadolinium-based contrast material did not cause significant changes in the ratios as compared with precontrast data. When chemotherapy was a component of a child's treatment protocol, we found a significant decline in NAA/Cr ratios. Patients who underwent both chemotherapy and radiation therapy showed a trend toward lower NAA-containing ratios if the chemotherapy was administered before the radiation therapy. Patients receiving whole-brain radiation had a trend toward lower NAA-containing ratios than did those who had only focal tumor treatment. CONCLUSION: In children with brain tumors, MR spectroscopy of brain tissue remote from the tumor reveals treatment-related biochemical changes.     

Clinical, neurodiagnostic, and MR findings in children with spinal and brain stem multiple sclerosis

PURPOSE: To describe the clinical, neurodiagnostic, and MR findings in seven children with brain stem and spinal multiple sclerosis. METHODS: Spinal or brain stem multiple sclerosis was diagnosed in seven children between 1986 and 1992. All patients had neurologic and MR examinations as well as neurodiagnostic testing, including spinal fluid analysis and brain stem and auditory evoked potentials. RESULTS: Three children had clinical findings and masslike lesions in the brain stem (two) or spinal cord (one) suggestive of neoplasm, which prompted biopsy (two) or radiation therapy (one). Five of six patients with spinal involvement had cord swelling with increased signal on T2-weighted images over at least three cord segments, and two children had essentially holocord involvement. Three children had normal cranial MR at presentation. CONCLUSIONS: Multiple sclerosis involvement of the brain stem and spinal cord may be associated with extensive swelling and MR signal changes suggestive of neoplasm without typical cerebral white matter abnormalities. Serial clinical and neuroimaging examinations may be necessary to make a definitive diagnosis of multiple sclerosis in children.     

Neurologic, MR imaging, and MR spectroscopic findings in eosinophilia myalgia syndrome

BACKGROUND AND PURPOSE: Eosinophilia myalgia syndrome (EMS), a multisystemic disease induced by exposure to L-tryptophan, may result in serious CNS abnormalities. The purpose of this study was to determine the pattern of neurologic characteristics, MR imaging abnormalities, and brain neurometabolites in EMS. METHODS: Sixteen patients with EMS and CNS abnormalities (CNS-EMS) and 12 control subjects underwent evaluation, including medical and neurologic examination, proton MR spectroscopy, and MR imaging. RESULTS: Neurologic findings that were increased in CNS-EMS included minor depression (100%), amnesia (88%), and intermittent confusion (38%), although fatigue (31%), motor disorders (31%), recurrent headache (19%), major depression (13%), and dementia (6%) also occurred, but at a lesser significance. Self-reported disability was markedly increased in CNS-EMS. MR imaging findings included subcortical focal lesions, focal lesions in deep white matter, cortical atrophy, ventricular dilatation, and diffuse and periventricular white matter abnormalities. MR spectroscopic findings established two distinct spectral patterns: 1) increased choline-containing compounds, decreased N-acetylaspartate, and increased lipid-macromolecules, consistent with inflammatory cerebrovascular disease; and 2) increased glutamine, decreased myo-inositol, and decreased choline, consistent with acute CNS injury or metabolic encephalopathy. CONCLUSION: Neurologic abnormalities, self-reported disability, brain lesions, and MR spectroscopic abnormalities are common in CNS-EMS. The pattern of cerebral lesions and neurometabolites is consistent with widespread inflammatory cerebrovascular disease. However, a subgroup of patients with CNS-EMS have neurometabolic changes consistent with a metabolic encephalopathy identical or similar to hepatic encephalopathy. The neurologic abnormalities in EMS and related hypereosinophilic syndromes should be interpreted cautiously, with the recognition that both cerebrovascular injury and secondary metabolic encephalopathies may be involved.     

MR imaging and localized proton MR spectroscopy in late infantile neuronal ceroid lipofuscinosis

PURPOSE: Late juvenile neuronal ceroid lipofuscinosis (NCL) is a lysosomal neurodegenerative disorder caused by the accumulation of lipopigment in neurons. Our purpose was to characterize the MR imaging and spectroscopic findings in three children with late infantile NCL. METHODS: Three children with late infantile NCL and three age-matched control subjects were examined by MR imaging and by localized MR spectroscopy using echo times of 135 and 5. Normalized peak integral values were calculated for N-acetylaspartate (NAA), choline, creatine, myo-inositol, and glutamate/glutamine. RESULTS: MR imaging revealed volume loss of the CNS, most prominently in the cerebellum. The T2-weighted images showed a hypointense thalamus and hyperintense periventricular white matter. Proton MR spectra revealed progressive changes, with a reduction of NAA and an increase of myo-inositol and glutamate/glutamine. In long-standing late infantile NCL, myo-inositol became the most prominent resonance. Lactate was not detectable. CONCLUSION: MR imaging in combination with proton MR spectroscopy can facilitate the diagnosis of late infantile NCL and help to differentiate NCL from other neurometabolic disorders, such as mitochondrial or peroxisomal encephalopathies.     

Bilateral orbital metastases from breast carcinoma. A case of false pseudotumor

OBJECTIVE: To inform clinicians of a metastatic orbital neoplasm that frequently masquerades as an orbital inflammatory syndrome and to stimulate thought regarding this neoplasm's fundamental pathobiology specific to its orbital involvement. DESIGN: Interventional case report and literature review. PARTICIPANTS: A 47-year-old woman with an acquired, bilateral, diffusely infiltrative orbital process is described. INTERVENTION: The clinical and radiographic features of the patient's orbital process are reported. The review of two prior fine-needle aspiration biopsy specimens failed to reveal a diagnosis. Histopathologic examination of an open surgical biopsy specimen included standard light microscopy of frozen and formaldehyde-fixed, paraffin-embedded tissue. RESULTS: Characteristics light microscopy findings suggested the diagnosis of metastatic lobular carcinoma of the breast. The patient refused all therapeutic intervention and died 9 months after orbitotomy. CONCLUSION: The presentation of breast carcinoma metastatic to the orbit as a bilateral infiltrative process is far more common than appreciated previously. Its rate of bilateral orbital involvement is 20%, whereas this rate for other adult neoplasms is much lower. The authors report an additional case, review the clinical features of previous case reports and series, and discuss aspects of the metastatic process. Breast carcinoma must be included in the differential diagnosis of infiltrative orbital processes encountered in adult female patients. When "orbital pseudotumor" is detected in an adult female patient, a thorough medical history must be obtained and physical examination performed. If a possible primary breast carcinoma is indicated, one must be wary of metastatic disease, and a histologic orbital diagnosis is warranted. The frequency of orbital metastasis and bilateral orbital involvement of this neoplasm reinforces the possibility for organ-specific metastases.     

In-phase and out-of-phase MR imaging of bone marrow: prediction of neoplasia based on the detection of coexistent fat and water

OBJECTIVE: The purpose of this study was to determine if gradient-echo MR imaging with TEs selected with fat and water in phase and out of phase can help predict the likelihood of neoplastic or nonneoplastic lesions in bone marrow. SUBJECTS AND METHODS: Thirty consecutive patients with 31 suspected bone marrow lesions underwent MR imaging, including two spoiled gradient-echo sequences identical in all parameters except TE, which was chosen such that fat and water were either in phase or out of phase. Relative ratios of the abnormal bone marrow signal intensity and a control site on the in-phase and out-of-phase images were expressed. The images were also assessed independently by two reviewers who were unaware of the patients' identities and clinical histories. Reviewers assessed decreased marrow signal intensity relative to control sites on the out-of-phase and in-phase images. Pathologic confirmation was obtained in 16 patients (17 lesions); the remainder of patients had either established diagnoses or determination of benignity based on stability of findings at 1 year. Relative ratios were compared with the Student's t test and receiver operating characteristic (ROC) curve analysis, and the reviewers' scores were evaluated with ROC curve analysis. RESULTS: The relative signal-intensity ratios were 1.03 +/- 0.13 for the neoplastic group and 0.62 +/- 0.13 for the nonneoplastic group (p < .0001). ROC curve analysis of the signal-intensity ratios showed a z-score of .99. A ratio cutoff value of 0.81 resulted in a 95% sensitivity and a 95% specificity for detection of neoplasm. Both reviewers achieved 100% sensitivity and 94-100% specificity for detection of neoplasms. CONCLUSION: In-phase and out-of-phase gradient-echo MR imaging of bone marrow signal-intensity abnormalities can help predict the likelihood of neoplastic or nonneoplastic lesions.     

MRI of groove pancreatitis

PURPOSE: The purpose of this work is to describe the findings on MRI in patients with groove pancreatitis, a specific form of chronic pancreatitis affecting the groove between the pancreatic head, the duodenum, and the common bile duct. METHOD: MR images, including MR cholangiopancreatography, of five patients with groove pancreatitis were reviewed. Three patients underwent pancreatoduodenectomy due to serve duodenal stenosis, and the MR findings were compared to the histologic findings. RESULTS: A sheet-like mass was demonstrated between the pancreatic head and the duodenum in all patients. The masses were hypointense relative to pancreatic parenchyma on T1-weighted images and iso- to slightly hyperintense on T2-weighted images. After administration of Gd-DTPA, the masses showed delayed enhancement. Histologically, fibrous scar tissue was detected in the groove. CONCLUSION: MR images can clearly demonstrate the fibrous tissue in the groove in groove pancreatitis, and MR cholangiopancreatography can also provide useful information.     

Catheter ablation of ventricular tachycardia associated with remote myocardial infarction: utility of the atrial transseptal approach

BACKGROUND: To determine the magnetic resonance (MR) imaging features of hepatic metastases from leiomyosarcoma and determine the pathologic basis for the MR appearance of these neoplasms. METHODS: MR examinations of eight patients with a total of 16 hepatic metastases from leiomyosarcoma were retrospectively reviewed. Hepatic metastases originated from a primary gastrointestinal (n = 6), uterine (n = 1), or retroperitoneal (n = 1) leiomyosarcoma. Correlation between MR features and pathologic findings was performed in 11 metastases from which histologic material was obtained. RESULTS: Among the 10 metastases seen on T1-weighted MR images, nine were homogeneous and one was heterogeneous. The latter contained areas of necrosis and hemorrhage on pathologic examination. Among the 16 metastases seen on T2-weighted MR images, 12 were well delineated and completely homogeneous, with a marked hyperintense signal ("hemangiomalike" pattern). These neoplasms were composed of smooth fibrous tissue without macroscopically visible areas of necrosis on pathologic examination. The remaining four metastases were heterogeneous and contained varying degrees of necrosis and hemorrhage or gelatinous tissue. CONCLUSION: A hemangiomalike pattern is the most common feature on T2-weighted MR images. We found that homogeneous hyperintensity of hepatic metastases from leiomyosarcoma on T2-weighted MR image does not reflect cystic changes.     

Proton MR spectroscopy of squamous cell carcinoma of the extracranial head and neck: in vitro and in vivo studies

PURPOSE: To determine the ability of in vitro one-dimensional and two-dimensional proton MR spectroscopy to help differentiate squamous cell carcinoma of the extracranial head and neck from normal tissues and to correlate the in vitro observations with clinical studies. METHODS: In vitro 1-D and 2-D correlated proton MR spectroscopy (11 T) was performed in tissue specimens of squamous cell carcinoma of the head and neck (n = 19), in normal tissue (n = 13), in metastatic cervical lymph nodes (n = 3), and in a squamous cell carcinoma cell line. In vivo 1-D proton MR spectroscopy (1.5 T) was performed in patients with squamous cell carcinoma (n = 7) and in healthy volunteers (n = 7). The ratio of the areas under the choline (Cho) and creatine (Cr) resonances were calculated for 1-D proton MR spectra for the in vitro tissue studies and correlated with the in vivo studies. Data from in vitro 2-D correlated spectroscopy were analyzed for differences in the presence or absence of various metabolites in samples of tumor and normal tissue. Statistical analysis consisted of 2 x 2 factorial repeated measures analysis of variance (ANOVA), discriminate analysis, and chi2 test. RESULTS: The mean in vitro 1-D proton MR spectroscopic Cho/Cr ratio was significantly higher in tumor than in normal tissue. The difference between the mean ratios appeared to increase with increasing echo time. All in vivo tumor Cho/Cr ratios were greater than the calculated mean in vitro tumor ratio, whereas six of the seven volunteers had no detectable Cho and Cr resonances. Two-dimensional correlated MR spectroscopic data revealed that a variety of amino acids have a significantly greater likelihood of being detected in tumor than in normal tissues. CONCLUSIONS: One-dimensional and 2-D proton MR spectroscopy can help differentiate primary squamous cell carcinoma and nodal metastases containing squamous cell carcinoma from normal tissue both in vitro and in vivo. In addition, 2-D spectroscopy can help identify the presence of certain amino acids in squamous cell carcinoma that are not detected in normal tissue.     

Breast carcinoma: MR imaging before re-excisional biopsy

PURPOSE: To investigate the role of magnetic resonance (MR) imaging in the examination of patients after excisional biopsy of breast carcinoma before re-excision. MATERIALS AND METHODS: Forty-seven patients underwent contrast material-enhanced MR imaging after initial excisional biopsy of breast carcinoma before further surgery. RESULTS: The positive predictive value of MR imaging for predicting residual disease was 82%; the negative predictive value was 61%. Fourteen patients had multifocal (n = 6) or diffuse (n = 8) carcinoma. The extent of tumor was correctly identified with MR imaging alone in nine of the 14 patients, with both mammography and MR imaging in three patients, with mammography alone in one patient, and with no imaging modality in one patient. In four of the 14 patients, management was altered from re-excision to mastectomy (n = 3) or from breast-conservation therapy to mastectomy (n = 1). CONCLUSION: MR imaging has a high positive predictive value for predicting residual tumor after excisional biopsy. The identification of mammographically and clinically unsuspected multifocal or extensive residual tumor may lend support for mastectomy rather than re-excision. However, false-negative findings due to postsurgical changes and false-positive findings due to enhancement of granulation tissue and benign breast tissue remain limitations.     

Wegener granulomatosis: CT and MR findings

PURPOSE: To demonstrate the spectrum of CT and MR imaging findings in patients with Wegener granulomatosis and to determine how often these findings could be attributed to either direct extension from paranasal or orbital disease sites, remote granulomas, or central nervous system (CNS) vasculitis. METHODS: We retrospectively reviewed the CT or MR studies of 15 patients with Wegener granulomatosis. RESULTS: Abnormal findings were seen in 7 patients (5 examined with MR imaging, 2 with CT). Findings included dural thickening and contrast enhancement (3 patients), infarcts (2 patients), regions of hyperintense signal on T2-weighted MR images (2 patients), and abnormal MR signal in the brain stem (2 patients). Three patients with imaging findings of dural enhancement and thickening were thought to have remote granulomatous lesions involving the dura. No patients had extension from sites external to the CNS or clinical findings suggestive of CNS vasculitis. CONCLUSION: The spectrum of CT and MR findings in Wegener granulomatosis includes dural thickening and enhancements cerebral infarction, and MR signal abnormalities in the brain stem and white matter. Presumed remote granulomatous lesions were the most common causes of CNS findings in this study. Complications related to non-CNS disease (eg, hypertension, endocarditis) also appear to have played a role in some patients.     

Polymerase chain reaction on cerebrospinal fluid for diagnosis of virus-associated opportunistic diseases of the central nervous system in HIV-infected patients

OBJECTIVE: To assess the diagnostic reliability of polymerase chain reaction (PCR) on cerebrospinal fluid (CSF) for virus-associated opportunistic diseases of the central nervous system (CNS) in HIV-infected patients. DESIGN: CSF samples from 500 patients with HIV infection and CNS symptoms were examined by PCR. In 219 patients the PCR results were compared with CNS histological findings. METHODS: Nested PCR for detection of herpes simplex virus (HSV) type 1 or 2, varicella zoster virus (VZV), cytomegalovirus (CMV), Epstein-Barr virus (EBV), human herpesvirus 6 (HHV-6), and JC virus (JCV) DNA. Histopathological examination of CNS tissue obtained at autopsy or on brain biopsy. RESULTS: DNA of one or more viruses was found in CSF in 181 out of 500 patients (36%; HSV-1 2%, HSV-2 1%, VZV 3%, CMV 16%, EBV 12%, HHV-6 2%, and JCV 9%). Among the 219 patients with histological CNS examination, HSV-1 or 2 was detected in CSF in all six patients (100%) with HSV infection of the CNS, CMV in 37 out of 45 (82%) with CMV infection of the CNS, EBV in 35 out of 36 (97%) with primary CNS lymphoma, JCV in 28 out of 39 (72%) with progressive multifocal leukoencephalopathy. Furthermore, HSV-1 was found in one, VZV in four, CMV in three, EBV in three, HHV-6 in seven, and JCV in one patient without histological evidence of the corresponding CNS disease. CONCLUSIONS: CSF PCR has great relevance for diagnosis of virus-related opportunistic CNS diseases in HIV-infected patients as demonstrated by its high sensitivity, specificity, and the frequency of positive findings.     

Putamen volume in idiopathic focal dystonia

PURPOSE: To determine the accuracy of magnetic resonance (MR) imaging in evaluating the invasive cervical carcinoma response to concurrent chemotherapy and radiation therapy. MATERIALS AND METHODS: MR imaging was performed before and after concurrent chemotherapy and radiation therapy in 18 patients with locally invasive cervical carcinoma. Surgery followed neoadjuvant therapy in all patients. The presence of a lesion, signal intensity, zonal anatomy integrity, vaginal and parametrial invasion, and lymph node enlargement was determined. Posttreatment MR and histopathologic findings were correlated. RESULTS: Fourteen patients had histopathologic confirmation of MR findings: Twelve had true-negative and two had true-positive findings. (Two had microscopic neoplastic foci beyond the spatial resolution of MR images; these foci do not change surgical treatment planning and probably do not influence prognosis. Therefore, these two patients were considered to have complete response). Four patients had false-positive findings; the hyperintense lesion on posttreatment MR images was due to a tunnel cluster pattern (focal hyperplasia of the endocervical glands with inflammation) in three patients and necrosis in one patient, without any evidence of neoplastic tissue. Thirty-three of 36 parametrial halves and 67 of 72 vaginal fornices were correctly interpreted on posttreatment images. Involvement of three parametrial halves and five fornices was overestimated at MR, because edema or inflammation was not distinguishable from tumor. CONCLUSION: MR imaging is 78% accurate in evaluation of tumor response; in 22% of patients, however, benign conditions were not distinguishable from tumor.     

MR of hypoxic encephalopathy in children after near drowning: correlation with quantitative proton MR spectroscopy and clinical outcome

BACKGROUND AND PURPOSE: Quantitative MR spectroscopy has a proved role in the investigation of hypoxia caused by near drowning. To date, no studies have addressed the MR imaging changes that may also accompany this condition. The purpose of this study was to describe the MR imaging findings in children with hypoxic encephalopathy caused by near drowning and to compare these findings with the results of qualitative and quantitative proton MR spectroscopy and clinical outcome. METHODS: Twenty-two children (6 months to 11 years old) admitted to the pediatric intensive care unit after near drowning incidents underwent cerebral MR imaging and quantitative proton MR spectroscopy. Clinical and imaging studies were reviewed retrospectively, and subjects were grouped according to outcome: good result, persistent vegetative state, and death. Images were scored for edema, basal ganglia changes, and cortical changes, and were compared with MR spectra and outcome at days 1 to 2, 3 to 4, and 5 or more. RESULTS: Six patients had a good outcome, four remained in a persistent vegetative state, and 12 died. Generalized/occipital edema correlated with poor outcome. Indistinct lentiform nuclei margins on T1-weighted images were a frequent finding (78%). Basal ganglia T2 hyperintensity correlated with poor outcome, progressing from a patchy/peripheral distribution to diffuse high intensity. Patchy high T2 signal in the cortex or subcortical lines were specific but insensitive for poor outcome, as were brain stem infarcts. CONCLUSION: MR images in children with hypoxic encephalopathy after near drowning show a spectrum of changes. The most sensitive prognostic result may be achieved by combining MR imaging with qualitative and quantitative MR spectroscopic data.     

Non-Hodgkin lymphoma of the central skull base: MR manifestations

OBJECTIVE: The aim of this study was to demonstrate the MR characteristics of non-Hodgkin lymphoma of the skull base to help in the differential diagnosis of this neoplasm from other conditions. MATERIALS AND METHODS: MR of five patients, 7-64 years old, with pathologically proved lymphomas of the skull base were reviewed. Three cases had primary skull base lesions involving the sphenoid bone and the cavernous sinus. One case with a nasal cavity lesion involving the skull base and one with a relapsing skull base lesion of previously treated tonsillar lymphoma were included. RESULTS: The lesions had signal intensities that were similar to that of gray matter of brain on both T1- and T2-weighted imaging. Bilateral cavernous sinuses were involved with encasement of internal carotid arteries in every case. Postcontrast MR showed homogeneous enhancement of the tumor with dural infiltration along the planum sphenoidale, clivus, or tentorium. The clivus was destroyed or replaced by tumors in adult cases but in two children the clivus was preserved with intact sphenooccipital synchondrosis. In one case the tumor extended to the extracranial portion through the jugular foramen. CONCLUSION: The MR findings of a permeative lesion of the skull base, invasion of the cavernous sinus without arterial narrowing, infiltration along the dural surface, and an iso- or hypointensity with brain on T2-weighted imaging should suggest lymphoma.     

Reversible MR findings of hemolytic uremic syndrome with mild encephalopathy

We report the reversible MR findings in a 7-year-old girl with hemolytic uremic syndrome and mild encephalopathy. The splenium of the corpus callosum showed isointense to low signal intensity on T1-weighted images and high signal intensity on T2-weighted images, representing local edema. These findings returned to near normal on MR images obtained 1 week later. The patient recovered without CNS impairment.     

Osteochondromalike parosteal osteosarcoma: a report of six cases of a new entity

OBJECTIVE: Our purpose was to describe a rare juxtacortical bone sarcoma with deceptively benign, osteochondromalike histologic characteristics. We present criteria by which this low-grade malignant neoplasm can be distinguished from other benign and malignant surface lesions of bone with particular emphasis on the imaging features. MATERIALS AND METHODS: Six cases of a low-grade, chondroossifying parosteal sarcoma of bone were reviewed. Patients included four males and two females 11 months to 66 years old. Histologic findings from initial tumors and from recurrent tumors were reviewed. Two musculoskeletal radiologists analyzed the imaging studies, which included plain films, CT scans, MR images, and a bone scan. RESULTS: Histologically, the lesions were characterized by a thin layer of proliferating, periosteally derived spindle cells overlying a thin, low-grade malignant cartilage cap that underwent calcification, neovascularization, and conversion into benign bone and marrow fat. These lesions were unique in that the malignant elements were only at their periphery. All six cases were initially misdiagnosed as benign lesions on pathologic evaluation. In each patient, imaging revealed a "pasted-on" ossified surface lesion with an intact underlying cortex and no medullary involvement. In three cases, recurrent tumors had histologic appearances consistent with conventional parosteal osteosarcoma. Dedifferentiation, metastases, and death occurred in one of these three cases. CONCLUSION: To our knowledge, this surface lesion of bone has not been specifically described. Whether this tumor constitutes a distinct entity or is a specialized variant of parosteal osteosarcoma is unclear. Precise radiologic-pathologic correlation is essential for appropriate diagnosis and management.     

Modeling social influences on public drinking

To evaluate the potential value of endoscopic ultrasonography in primary gastric lymphoma, we compared endoscopic ultrasonography findings with endoscopic and histologic findings in 15 patients in whom the diagnosis had been established by radiography and endoscopy, including forceps biopsy. The patients were divided into four groups according to the endoscopic ultrasonography findings. The groups included the following: superficially spreading type (six patients), diffusely infiltrating type (three patients), mass-forming type (four patients), and mixed type (two patients). The endoscopic ultrasonography findings correlated well with the endoscopic, macroscopic, and histologic findings. The histologic findings in nine patients with the endoscopic ultrasonography superficially spreading type or diffusely infiltrating type revealed B-cell lymphoma arising from mucosa-associated lymphoid tissue, which shows slowly infiltrative growth. In four patients with the endoscopic ultrasonography mass-forming type, on the other hand, the tumor histologic finding consisted of diffuse large-cell or diffuse mixed-cell type. Our results indicate that endoscopic ultrasonography may provide information helpful for the management of primary gastric lymphoma.     

Hallervorden-Spatz disease: MR and pathologic findings

PURPOSE: To compare the MR findings of eight cases with clinical diagnosis of Hallervorden-Spatz disease (HSD) with the pathologic findings of two other cases of HSD. MATERIALS AND METHODS: The eight imaged cases were studied with 0.5-T (seven cases) and/or 1.5-T (five cases) units. Six patients also had CT scans. The two other cases with proven HSD had detailed histologic evaluation. RESULTS: The 1.5-T findings showed abnormalities confined to the pallidum, which presented a diffuse low signal intensity in T2-weighted images, and an anteromedial area of high signal intensity (eye-of-the-tiger sign). In 0.5-T studies, low signal intensity was less evident and poorly detectable in spin echo, but gradient-echo images could enhance its demonstration; the area of high signal intensity was always well demonstrated. In three cases (three with 1.5 T, one with 0.5 T) a central spot of low signal intensity was seen in this area. The pathologic cases, in addition to neuroaxonal swellings and iron deposits, exhibited areas of "loose" tissue with vacuolization and lesser amounts of iron in the anteromedial part of the pallidum, in a location corresponding to the area of high signal intensity of the imaged cases. CONCLUSION: Comparison of MR findings with the pathologic studies demonstrates that the low signal intensity in T2-weighted images at 1.5 T corresponds to iron deposits in a dense tissue, and that the high signal intensity of the eye-of-the-tiger sign corresponds to an area of loose tissue with vacuolization. No correlation was found in the two pathologic cases for the central spot of low signal intensity.