The accuracy of CT and MR evaluation of the sella turcica for detection of adrenocorticotropic hormone-secreting adenomas in Cushing disease

PURPOSE: To document the accuracy of CT and MR of the sella turcica for detecting adrenocorticotropic hormone-secreting adenomas in Cushing disease. METHODS: The radiologic findings of the sella turcica prior to transsphenoidal surgery are reviewed in 141 patients who had biochemical evidence of pituitary-dependent Cushing disease. Axial thin-collimation CT scans with sagittal and coronal reformations before and after contrast enhancement were obtained in 125 patients. Seventy-eight patients had MR examinations with a 1.5-T superconducting magnet. In 11 of the patients gadolinium-enhanced MR scans were also obtained. The preoperative interpretation of the imaging studies was correlated with the surgical findings and patients follow-up. RESULTS: The sella turcica was enlarged in 43 cases (30%). In 125 patients reformatted or direct coronal thin-collimation CT scans were available. Seventy-eight of the patients had MR. In the 12 patients with pituitary macroadenomas, the accuracy of CT (n = 10) and MR (n = 10) in respect to detection of the lesion was 100%. Of the 98 microadenomas assessed by CT, 47 (48%) were directly depicted as distinct hypodense lesions. In only 31 of 73 cases (42%), however, could CT predict the precise anatomic location and extent of the lesions. Only patients in whom the hypercortisolism was corrected by later surgery were considered for the correlation analysis. Of the 52 microadenomas assessed by MR, 28 (53%) were directly depicted as distinct lesions of reduced signal intensity on T1-weighted images, and in only 21 of 41 cases (52%) did MR show good correlation to the surgical findings. Some degree of partially empty sella was found in 22% of the patients. CONCLUSIONS: Although both the sensitivity and the diagnostic accuracy of imaging methods of the sella turcica have been considerably improved in comparison with previous reports, they still provide only a minor contribution to the diagnosis and differential diagnosis of Cushing syndrome.     

Radiological features of focal nodular hyperplasia of the liver in children

BACKGROUND: Focal nodular hyperplasia (FNH) is an unusual hepatic tumour in children and should be distinguished from other hepatic lesions. OBJECTIVE: To describe the imaging characteristics of FNH in children. MATERIALS AND METHODS: We examined five patients (three boys and two girls, mean age 9.4 years) with pathologically confirmed FNH. The diagnosis was obtained by tumour resection (n = 4) and percutaneous needle biopsy (n = 1). One patient with multiple FNHs showed recurrent lesions after tumour resection. All patients were studied with US (including colour and power Doppler US [n = 3]) and CT. Dynamic enhanced CT scans were available in three patients. MRI (n = 2) or coeliac angiography (n = 1) was performed in three patients. RESULTS: Seven of eight FNH lesions in five patients were demonstrated by imaging. The average size of the lesions was 6.5 cm. Six lesions detected on US showed variable echogenicity with a central hyperechoic scar (n = 2). On Doppler examination, central or peripheral hypervascular areas were seen (n = 3). Six lesions detected on contrast-enhanced CT showed high attenuation (n = 4) or iso-attenuation (n = 2). On early phase scans, all the lesions (n = 3) showed high attenuation. Irregular linear or ovoid central scars were detected in two patients on CT. MR demonstrated three lesions in two patients, one of which had not been detected by US or CT. A central low signal intensity scar (n = 1) was seen on T2-weighted MRI. Coeliac angiography performed in one patient showed a hypervascular mass with homogeneous staining. CONCLUSION: FNH in children shows a wide spectrum of imaging findings on various radiological examinations and the typical central scar was not always seen on imaging studies. Dynamic enhanced CT obtained in the early phase and colour Doppler studies may be helpful in the diagnosis of FNH by allowing characterisation of tumour vascularity. FNH should be included in the differential diagnosis of liver mass in children.     

Comparison of computerized tomography and magnetic resonance in the assessment of benign and malignant pleural diseases

To compare the diagnostic capabilities of Computed Tomography (CT) and Magnetic Resonance Imaging (MRI) in differentiating benign from malignant pleural disease, we examined with MRI at 0.5 T forty-five patients with pleural lesions identified on CT scans. For 34 patients, a final diagnosis of malignant (n = 18) or benign (n = 16) disease was made. T1, proton density/T2 and enhanced T1-weighted spin-echo images were acquired. CT and MR images were independently studied by two observers, who were unaware of the final diagnosis. Various morphological features suggesting benign or malignant pleural disease were evaluated. On the basis of the morphological CT features, a final diagnosis of benignity of malignancy was expressed in terms of two different levels of confidence-probable or definitive. The MR signal intensity of pleural lesions was compared with that of intercostal muscles (isohypointense or hyperintense). No significant differences were observed between CT and MR morphological findings. High signal intensity on proton density/T2-weighted images was observed in all malignant lesions and in 2 benign lesions (100% sensitivity, 87% specificity). In the absence of this sign (i.e., isointense or hypointense signal), the lesions were always benign (100% negative predictive value). All the definitive CT diagnoses were correct, while 6 of 17 probable CT diagnoses were incorrect. In the subgroup of lesions misinterpreted with CT, MR signal intensity on long-TR images always allowed the correct differentiation of benign from malignant conditions. To conclude, MR signal intensity is a valuable additional feature to differentiate benign from malignant pleural disease. We suggest the use of MRI in the pleural lesions where the level of confidence of CT diagnosis is low.     

Gliomatosis cerebri

PURPOSE: To characterize gliomatosis cerebri on computed tomographic (CT) and magnetic resonance (MR) images. MATERIALS AND METHODS: MR and CT studies of 22 patients with cerebral gliomatosis were reviewed retrospectively. Tumor was confirmed with autopsy (n=5) or biopsy. Distribution and extent of disease were assessed, and disease progression was followed. RESULTS: Tumor involved at least two lobes of the brain in all patients, with extension to the corpus callosum in 12, basal ganglia and thalamus in 17, brain stem in three, and cerebellum in two patients. Widespread invasion with hyperintensity was noted on proton-density- and T2-weighted MR images. At CT, areas of hypo- or isoattenuation were noted, and no contrast enhancement occurred. Extent of tumor was greater on MR images than on concurrent CT scans in all patients. The MR findings closely correlated with the autopsy findings. CONCLUSION: Gliomatosis cerebri is best detected with MR imaging. The pattern is infiltrative with enlargement of cerebral structures.     

Effects of a high NaCl diet on eating and drinking patterns in pygmy goats

PURPOSE: Our goal was to determine the spectrum of 2-[18F]fluoro-2-deoxy-D-glucose (FDG) PET findings in patients with round atelectasis (RA). METHOD: All patients from 1992 to 1997 with radiologic features of RA and FDG-PET scans were evaluated. There were nine men ranging in age from 52 to 75 years (mean 65 years). All had chest radiographs and CT scans that were correlated with FDG-PET. FDG-PET was considered positive if lesion activity was greater than mediastinal activity and negative if lesion activity was the same as or less than mediastinal activity. RESULTS: Nine patients had 10 lesions, ranging in size from 1.2 to 5.0 cm (mean 3.1 cm). Lesion locations were right lower lobe (n = 5), left lower lobe (n = 4), and lingula (n = 1). All lesions were homogeneous and of soft tissue attenuation on CT. None contained air bronchograms or calcification. All had in-curving vessels and bronchi (comet tail sign), adjacent pleural thickening, and volume loss on CT. All lesions were negative on FDG-PET. Four lesions were percutaneously biopsied and showed chronic inflammation consistent with RA. Two lesions were unchanged on 2 and 3 year follow-up CT and were presumed to be RA as were four other lesions with characteristic CT features and negative FDG-PET. CONCLUSION: Our experience suggest that RA in not metabolically active on FDG-PET imaging. Thus, FDG-PET scans can play a role in differentiating RA from malignancy when there are few or atypical features of RA on chest radiographs and CT.     

Polymorphism and disorder of poly(dA).poly(dT) in fibers

OBJECTIVE: The purpose of this report is to describe the clinical history, treatment, pathology, and imaging in two cases of rare CNS infection caused by free-living amebas. The Naegleria fowleri and Acanthamoeba species cause primary amebic meningoencephalitis and granulomatous amebic encephalitis, respectively. We describe the neuroimaging findings of a case involving a nonspecific cerebral edema pattern in primary amebic meningoencephalitis and a case involving focal enhancing lesions in granulomatous amebic encephalitis. CONCLUSION: Primary amebic meningoencephalitis and granulomatous amebic encephalitis have a grave prognosis and, although rare, should be considered in the differential diagnosis for patients who present with appropriate histories and imaging findings, including nonspecific brain edema on CT in primary amebic meningoencephalitis and focal punctate enhancing lesions in the posterior cranial fossa on T1-weighted MR imaging in granulomatous amebic encephalitis.     

Synovial hemangioma: imaging features in eight histologically proven cases, review of the literature, and differential diagnosis

OBJECTIVE: This study was undertaken to describe the imaging characteristics of synovial hemangioma, with the goal of improving the disappointing rate (22%) of clinical diagnosis of this condition. A review of the literature and the differential diagnosis of intra-articular lesions, including synovial osteochondromatosis and pigmented villonodular synovitis, are also presented. PATIENTS: The subjects of the study were 8 patients (4 males, 4 females; age range: 5-47 years; mean age: 19 years) with histologically confirmed synovial hemangioma involving the knee (n = 7) or wrist (n = 1). We retrospectively examined the imaging studies performed in these patients, including plain radiography (n = 8), magnetic resonance imaging (MRI; n = 4), angiography (n = 3), arthrography (n = 2), and contrast-enhanced computed tomography (CT; n = 2). RESULTS: Plain radiographs showed a soft tissue density suggesting either joint effusion or a mass in all patients. Phleboliths and bone erosions on plain films in four patients with extra-articular soft tissue involvement pointed to the correct diagnosis. Angiography, showing fine-caliber, smooth-walled vessels, contrast pooling in dilated vascular spaces, and early visualization of venous structures, was diagnostic in two patients. Neither arthrography nor CT yielded specific enough findings. MRI was consistently effective in allowing the correct diagnosis to be made preoperatively, showing an intra-articular or juxta-articular mass of intermediate signal intensity on T1-weighted images and of high signal intensity of T2- or T2*-weighted images with low-signal channels or septa within it. A fluid-fluid level was found in two patients with a cavernous-type lesion. CONCLUSION: Despite the limited nature of this study, it shows clearly that MRI is the procedure of choice whenever an intra-articular vascular lesion such as synovial hemangioma is suspected. Nonetheless, phleboliths and evidence of extra-articular extension of plain radiographs point to angiography as an effective procedure of first resort because it can be combined with embolotherapy.     

Cerebral complications of murine monoclonal CD3 antibody (OKT3): CT and MR findings

Treatment of acute renal allograft rejection with mouse monoclonal antibody (OKT3) is associated with systemic and neurologic side effects. We describe cerebral abnormalities in a 13-year-old boy with steroid-resistant renal allograft rejection. After treatment with OKT3, an acute neurologic syndrome developed, including seizures, lethargy, and decreased mental function. CT and MR imaging revealed confluent cerebral lesions at the corticomedullary junction. Contrast-enhanced MR images showed patchy enhancement, indicating blood-brain barrier dysfunction. The diagnosis of OKT3-induced encephalopathy with cerebral edema and capillary leak syndrome was made. Although CT and MR findings are nonspecific, neuroradiologists should be aware of this condition in transplant patients treated with OKT3.     

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.     

Nontumorous arterioportal shunt mimicking hypervascular tumor in cirrhotic liver: two-phase spiral CT findings

PURPOSE: To determine the two-phase (hepatic arterial phase [HAP] and portal venous phase [PVP]) spiral computed tomographic (CT) findings of a nontumorous arterioportal shunt in the cirrhotic liver that can mimic a hypervascular tumor. MATERIALS AND METHODS: For 14 months, 803 patients with known or suspected hepatocellular carcinoma were referred for initial or repeated transcatheter arterial chemoembolization (TACE). Twenty-nine hyperattenuating lesions on HAP CT images obtained in 25 patients (23 men, two women; age range, 39-70 years) were regarded as nontumorous arterioportal shunts and were included in this study. The diagnosis of nontumorous arterioportal shunt was established by four radiologists who reviewed the two-phase spiral CT images and hepatic angiograms. RESULTS: The longest dimension of the lesion was 1.0-7.9 cm (mean dimension, 2.9 cm). The morphology at HAP CT was wedge-shaped in 25 (86%), geographic (ie, focal area with irregular outline) in two (7%), and nodular in two (7%) lesions. All lesions were homogeneous in attenuation. Hyperattenuating linear branching structures that represented early opacification of portal veins were demonstrated during the HAP in nine (31%) lesions. PVP CT images showed these lesions as isoattenuating (n = 20 [69%]) or slightly hyperattenuating (n = 9 [31%]). Iodized oil CT images showed faint or no accumulation of iodized oil in all lesions. CONCLUSION: In cirrhotic liver, nontumorous arterioportal shunts can be a cause of pseudolesions that mimic hypervascular tumors at two-phase spiral CT. Lesions that have the typical wedge-shaped and homogeneous appearance with or without internal linear branching structures during the HAP and that are isoattenuating or slightly hyperattenuating during the PVP can suggest this unusual condition.     

Age-related changes of the insular cortex and lateral ventricles: conventional MRI volumetric measures

RATIONALE AND OBJECTIVES: The authors correlate computed tomography (CT) findings in biphasic spiral technique with histopathology in patients with hepatocellular carcinoma (HCC) who had undergone liver resection (LR) or orthotopic liver transplantation (OLT). METHODS: Preoperative biphasic spiral CT findings in 33 consecutive patients (23 men, 10 women, aged 43-74 years; LR group: n = 17; OLT group; n = 16) with liver cirrhosis and HCC were reviewed retrospectively by consensus of two radiologists and correlated with pathology from liver specimens. RESULTS: Of the 16 patients in the OLT group with 1 to 5 confirmed HCC lesions (total lesions: 29; mean lesion diameter: 2 cm; range: 0.6-5.0 cm), CT before OLT depicted 22 lesions in 15 patients (sensitivity for lesions with a diameter of 0.5-1.0 cm, 20%; for lesions 1.1-2.0 cm, 82%; and for lesions 2.1-3.0 cm and > 3.0 cm, 86% and 100%, respectively). Among the 17 patients in the LR group (total lesions: 21; mean lesion diameter: 5.4 cm; range: 1.0-11.0 cm), CT detected 18 lesions. Lesion-by-lesion sensitivity, as correlated with pathology, was calculated at 76% and 86% in the OLT and LR groups, respectively (overall sensitivity, 80%). The diameter of CT detected lesions, compared with liver specimens, corresponded in 90% of lesions (maximum deviation, 15%). Characteristic CT findings of HCC included unenhanced hypoattenuating focal liver lesions (32 lesions), with hyperattenuation (38 lesions) in the arterial phase of contrast material administration. CONCLUSIONS: Biphasic spiral CT for preoperative HCC detection correlated with pathology in 80%, thus proving this technique to represent a sensitive imaging modality for pretherapeutic evaluation of HCC.     

Contrast-enhanced MR "magnetization transfer technique". Improved tumor contrast, delineation and visibility of intracranial malignant gliomas and metastases in radiosurgical treatment planning

AIMS: To improve tumor conspicuity and delineation on contrast-enhanced T1-weighted MR images with and without magnetization transfer (MT) contrast as a strategy to improve the macroscopic boost volume definition in the planning process of radiosurgery in patients with high grade gliomas or metastatic brain lesions. PATIENTS AND METHODS: Thirty-two patients (mean age 47 years) with histologically proven or suspected high grade glioma (n = 12) or metastatic brain lesions (n = 20) were prospectively examined by MR imaging. After the administration of gadolinium dimeglumine (0.1 mmol/kg body weight) the lesions were imaged with a T1-weighted MT-fast low angle shot (FLASH) pulse sequence and with a conventional T1-weighted SE sequence without MT saturation. RESULTS: The mean CNR of enhancing lesions on T1-weighted MT-FLASH was 15 +/- 5 compared to 11 +/- 4 on SE images, representing a significant (p < .01) improvement. The mean tumor diameter of malignant gliomas was significantly (p < .01) larger measured on T1-weighted MT-FLASH images compared to those obtained from T1-weighted SE images and were comparable for metastatic lesions. Lesion conspicuity and delineation were improved in 50% of patients with high grade gliomas and in 35% of patients with brain metastases. Lesion conspicuity was markedly improved in the posterior fossa. Additional contrast enhancing lesions were detected in 10% of patients with metastases on MT-FLASH images. CONCLUSIONS: It is concluded that contrast-enhanced MT-FLASH images may improve lesion detection and delineation in the planning process of radiosurgery in patients with intracranial high grade gliomas or metastases or even alter the treatment approach.     

Computer-aided studies on the spatial structure of the small hepatitis B surface protein

Progressive Multifocal Leukoencephalopathy (PML) is a subacute demyelinating opportunistic infection of the central nervous system which frequently occurs in AIDS. CT and MR, together with clinical and virological findings, can suggest a correct diagnosis in most cases, thus avoiding stereotactic biopsy which is too invasive considering the lack of therapy and the poor prognosis of this disease. In this study we reviewed the CT and MR findings of 16 proved AIDS-related PML cases. PML lesions appeared as hypodense on CT, hypointense on T1w, hyperintense on PDw and T2w MR images. CT was less sensitive than T2w MR images and underestimated the number of lesions and/or disease extent. On the basis of our findings during the progression of the lesions we observed two different patterns of PML presentation and evolution i.e., "single" and "multifocal". Single lesions generally involve subcortical white matter (arcuate fibers) of parietal lobe and spread to the contralateral hemisphere across the corpus callosum; multiple "patchy" lesions can be localized variably in the cerebral hemispheres and also in the brainstem and cerebellar hemispheres.     

Neuroimaging of hypoglycemia

INTRODUCTION: Sustained hypoglycemia causes serious cerebral damage. The cortex, hippocampus and basal ganglia are particularly vulnerable to this. Exceptionally, there have been communications regarding neuroimaging visualization of cerebral lesions attributable to hypoglycemia only. We present the case of a woman who suffered hypoglycemic coma with permanent neurological damage. Lesions were seen on magnetic resonance (MR) and cranial computerized tomography (CT). CLINICAL CASE: A 22 year old woman with no vascular risk factors was admitted to hospital in hypoglycemic coma, after attempting suicide with oral antidiabetic drugs. The duration of the coma was unknown. On admission the glycaemia was 28 mg/dl. Cranial CT scan was normal during the first 24 hours. Cerebral MR scan one week late showed hyperintense lesions in T2, basal ganglia and left hippocampus. The cranial CT scan one year later showed diffuse atrophy, with bilateral lesions of low attenuation in the basal ganglia and dilatation of the ventricular system. CONCLUSIONS: It is unusual to see lesions secondary to hypoglycemia on neuroimaging investigations. The etiopathogenic mechanism is still unknown and it has generally been described in diabetic patients. In our case these lesions can only be attributed to hypoglycemia. MR is more sensitive than cranial CT scan for the detection of these lesions during the acute phase.     

Magnetic resonance imaging of focal liver lesions. Comparison of the superparamagnetic iron oxide resovist versus gadolinium-DTPA in the same patient

RATIONALE AND OBJECTIVES: The authors assess the efficacy of static and dynamic magnetic resonance (MR) imaging using the superparamagnetic iron oxide SHU-555A (Resovist) versus standard dose of gadolinium (Gd)-DTPA in patients with focal liver lesions. METHODS: Magnetic resonance imaging was performed in 30 patients suffering from histopathologically verified malignant (n = 22) and benign (n = 8) liver lesions. T2-weighted conventional and fat-suppressed as well as T1-weighted sequences were used before, during, and after fast intravenous administration of Resovist (1 mL/minute) at three doses of 4, 8, and 16 mumol/kg body weight. One week before the Resovist-enhanced MR imaging study 20 patients underwent Gd-DTPA-enhanced MR imaging. RESULTS: Detection rate was improved for metastatic lesions revealing 36 lesions unenhanced versus 53 focal lesions using Resovist-enhanced MR imaging. Gadolinium-DTPA-enhanced scans showed no additional lesion versus unenhanced and Resovist-enhanced MR imaging. Static and dynamic imaging demonstrated no measurable percentage signal intensity loss (PSIL) using Resovist-enhanced MR imaging versus a percentage enhancement of 79.7% in Gd-DTPA enhanced scans. In the dynamic T2-weighted sequences, hepatocellular carcinoma nodules (n = 4) showed a rapid decrease in signal intensity starting at 44 seconds. Postinfusion of Resovist followed by a low, constant increase in signal intensity. Gadolinium-DTPA enhanced scans showed a percentage enhancement of 73.4 focal nodular hyperplasia (FNH) and hemangioma revealed a strong and early dose-dependent PSIL 44 to 60 seconds postinfusion with a prolonged signal loss for the FNH in the late study. Statistical evaluation revealed a statistically significant superiority of Resovist-enhanced MR imaging concerning the detection and delineation of focal liver lesions compared with unenhanced and Gd-DTPA enhanced scans (P < 0.05). CONCLUSIONS: The fast infusion of the new superparamagnetic contrast agent Resovist shows advantages for dynamic and static MR imaging of focal liver lesions.     

Chronic obstructive pulmonary disease is associated with an increase in urinary levels of isoprostane F2alpha-III, an index of oxidant stress

BACKGROUND: The natural history of cerebral venous malformations has not been well documented, and the clinical significance of these common lesions remains controversial. OBJECTIVE: The objective of this study was to follow longitudinally the clinical course of patients with cerebral venous malformations to document the natural history of the lesion. METHODS: Ninety-two patients with radiographically confirmed venous malformations were entered into the study between 1987 and 1996. Annual follow-up was maintained by clinic visits and/or phone interviews. Sixty-three patients (25 men and 38 women) with more than 1 year of follow-up were analyzed. McNemar's test and logistic regression analysis was applied to prevalence of presenting symptoms over time. An average per patient follow-up of 4.2 years yielded 2,721 retrospective and 301 prospective lesion-years for analysis. RESULTS: Average age at diagnosis was 39.1 years (SD, 18.7 years; range, 2 to 73 years). The most frequent lesion locations included the frontal lobe (55.6%, n=35) and the cerebellum (27%, n=17). The most frequent presentations included headache (50.8%, n=32), focal neurologic deficits (39.7%, n=25), and seizure (30.2%, n=19). Prevalence of headache (p=0.048) and seizure (p=0.016) decreased over time without treatment of the lesion. A second cerebrovascular lesion was identified in 12 patients (19%). Two patients had a symptomatic intracerebral hemorrhage attributable to their venous malformation. Risk of hemorrhage was 0.15% per lesion-year (95% CI, 0.06 to 0.38%). CONCLUSIONS: This study establishes that the natural history of venous malformations is benign, that the risk of hemorrhage from these lesions is negligible, and that conservative therapy is warranted.     

Single-photon emission CT findings in acute Japanese encephalitis

PURPOSE: To determine the usefulness of single-photon emission CT (SPECT) in the diagnosis of acute Japanese encephalitis (JE). METHODS: We examined 10 patients (six men and four women; mean age, 69 years) with viral encephalitis. We divided the cases into two groups: the JE group (n = 4) and the non-JE group (n = 6; two with herpes simplex encephalitis and four with encephalitis of unknown origin). All cases were investigated with 99mTc-hexamethylpropyleneamine oxime (HMPAO) SPECT within 15 days after the onset of symptoms. Two patients in the JE group were also examinated by SPECT at a later stage. In all cases MR imaging was performed after the SPECT study. RESULTS: In the acute stage, all patients in the JE group showed a marked increase of HMPAO uptake that matched the hyperintense area observed on MR images in the thalami and putamina bilaterally. Follow-up SPECT studies of two patients with JE revealed a decrease of HMPAO deposition in the areas of high uptake. None of the patients in the non-JE group had an increased accumulation of HMPAO in the thalami or the putamina. CONCLUSIONS: SPECT is helpful in differentiating JE from herpes simplex encephalitis and other types of encephalitis. SPECT may be useful as a diagnostic tool in the early stages of JE.     

Improved retroperitoneal and gastrointestinal sonography using oral contrast agents in a porcine model

PURPOSE: To evaluate use of functional imaging with positron emission tomography (PET) versus computed tomography (CT) for detection of extranodal lymphoma spread. MATERIALS AND METHODS: Eighty-one consecutive and previously untreated patients with malignant non-Hodgkin lymphoma (n = 43) or Hodgkin disease (n = 38) were examined with 2-[fluorine-18]fluoro-2-deoxy-D-glucose (FDG) PET and contrast material-enhanced CT. Concordant findings at both CT and FDG PET were regarded as actual locations of disease; discordant results were resolved on the basis of biopsy or follow-up results when possible. RESULTS: Forty-two lesions were identified at both PET and CT, and 19 were verified with biopsy results. PET demonstrated a further 24 lesions. Verification was possible in 15 of these lesions with biopsy (n = 10), magnetic resonance imaging (n = 1), scintigraphic (n = 1), or follow-up (n = 3) results. In 14 of these 15 lesions, PET findings were confirmed (bone marrow, nine; spleen, three; other, two). Seven lesions not visualized at FDG PET were identified at CT, six of which were verified with biopsy (n = 2) or follow-up (n = 4) results. Five of these six CT findings were found to be erroneous. In 13 patients, PET findings led to changes in tumor staging. CONCLUSION: PET may provide more information about extranodal lymphoma than does incremental CT.     

Identification of early postmitotic cells in distinct embryonic sites and their possible roles in morphogenesis

This article reviews MRI findings of parasitic diseases of the central nervous system (CNS), with emphasis on neurocysticercosis, which is by far the most common CNS parasitic infection worldwide. MRI findings of neurocysticercosis are various, depending on the location (parenchymal, cisternal, ventricular, and spinal forms), and temporal evolutional stages (vesicular, colloid vesicular, granular nodular, and nodular calcified stages) of the worm. Classical findings of each location and stage are presented. Characteristic MRI findings of cerebral toxoplasmosis frequently seen in patients with acquired immunodeficiency syndrome (AIDS), paragonimiasis, and sparganosis that have most commonly been reported in East Asia are also illustrated. MRI is superior to CT scan in the evaluation of most CNS parasitic infections and is nearly diagnostic, particularly in endemic areas. Contrast-enhanced study is essential not only for specific diagnosis of the disease, but also for assessment of the inflammatory activity.     

BRCA1 splice variants BRCA1a and BRCA1b associate with CBP co-activator

PURPOSE: To define the appearance of gastric stromal sarcomas at magnetic resonance (MR) imaging. MATERIALS AND METHODS: Nine patients with gastric stromal sarcoma underwent MR imaging with the following sequences: nonenhanced and gadolinium-enhanced breath-hold, T1-weighted, spoiled gradient-recalled echo (n = 9); fat-suppressed, T2-weighted, fast spin echo (n = 9); and breathing-independent, half-Fourier rapid acquisition with relaxation enhancement (n = 6). Lesion morphology, signal intensity features, and relationships to the gastric wall and surrounding organs were retrospectively evaluated. The diagnosis of gastric stromal sarcoma was histologically proved in all patients. RESULTS: The nine tumors were solitary, multilobulated, shaped irregularly, predominantly exophytic, and large (diameter range, 7-28 cm [mean, 15.8 cm]). The epicenters of all lesions were extrinsic to the stomach, and all lesions arose from the gastric cardia or body. Regions of necrosis and hemorrhage were detected in all cases. Marginal definition on MR images corresponded to histologic grade: High-grade neoplasms possessed ill-defined margins, and low-grade neoplasms demonstrated more well-defined margins. Relationships to surrounding organs depicted at MR imaging corresponded well with histopathologic findings. CONCLUSION: Gastric stromal sarcomas demonstrate characteristic MR imaging features, which correspond well with histopathologic findings. The direct multiplanar capability of MR imaging facilitates delineation of relationships of the tumors to the stomach and surrounding organs.