Value of radioisotope axial tomography in the diagnosis of a cystic malignant glioma

A case is presented in which the patient had a deep tumour in the posterior aspect of the temporal lobe close to midline. The brain scan including a transverse section view at 8 cm from the vertex was negative and the other neuroradiological examinations inconclusive. One month later a follow up brain scan was performed and the conventional views were negative whereas the transverse section scan done at 10 cm from the vertex showed a lesion in the left temporo-parietal region and near midline. Three months later a repeat brain scan was done, and the lesion was visualized in the conventional views and confirmed by angiogram.     

Value of radioisotope axial tomography in the diagnosis of a cystic malignant glioma

A case is presented in which the patient had a deep tumour in the posterior aspect of the temporal lobe close to midline. The brain scan including a transverse section view at 8 cm from the vertex was negative and the other neuroradiological examinations inconclusive. One month later a follow up brain scan was performed and the conventional views were negative whereas the transverse section scan done at 10 cm from the vertex showed a lesion in the left temporo-parietal region and near midline. Three months later a repeat brain scan was done, and the lesion was visualized in the conventional views and confirmed by angiogram.     

Fatal cerebral air embolism as a complication of transbronchoscopic lung biopsy: a case report

A rare complication of transbronchoscopic lung biopsy, namely a cerebral air embolism, is presented. The course of events following the embolic episode in the form of a fall in blood pressure, bradycardia and convulsions is documented, as is the presence of an air emboli on the CT scan of the brain with subsequent resorption of the emboli on the follow-up scan. The salient features of the case are the rarity of the complication and the excellent temporal depiction of imaging findings on CT scan demonstrated as resorption of air emboli and subsequent watershed territory infarcts.     

Stability of cerebral blood flow measures using a split-dose technique with (99m)Tc-exametazime SPECT

AIM: To determine whether there is stability of cerebral blood flow (CBF) measures using single photon emission computed tomography (SPECT) imaging in healthy controls in a test-retest split-dose paradigm. Such a paradigm is frequently used in the clinical and research setting to assess various brain states. METHODS: Five healthy volunteers underwent two brain SPECT scans after the administration of low and high doses of (99m)Tc-exametazime. The first SPECT scan was acquired approximately 30 min after the intravenous injection of approximately 259 MBq of (99m)Tc-exametazime. The second SPECT scan was acquired approximately 30 min after the intravenous injection of 925 MBq of (99m)Tc-exametazime. Both scans were acquired over approximately 30-45 min and the images were reconstructed using filtered backprojection, a low-pass filter and Chang's first-order attenuation correction. Values were obtained for regions of interest (ROIs) in major brain structures and normalized to whole brain activity. Counts on the second SPECT scan were also decay corrected for activity from the first scan. RESULTS: The results demonstrated a strong correlation between the low-dose and high-dose scans for all regions (r = 0.86, P<0.0001). Symmetries were preserved with a strong correlation between low-dose and high-dose scans (r = 0.70, P<0.0001). Finally, most regions demonstrated less than a 5% difference between the low-dose and high-dose scans. CONCLUSIONS: The results of this study demonstrate that the split-dose technique can be employed for clinical and research applications to measure CBF in different brain states using two SPECT scans on the same day.     

Necessity of a uniform start for scanning after FDG injection in brain PET study

The authors' goal was to show the importance of starting scanning at a uniform time after F-18 fluorodeoxyglucose injection in positron emission tomography (PET) brain study. METHOD: Fifteen healthy normal subjects underwent FDG-PET to obtain glucose metabolic images starting 60 min and 70 min after FDG injection, respectively. The two sets of images were compared in a voxel-by-voxel analysis. RESULTS: In the bilateral posterior cingulate gyrus, parietal and frontal association cortices, the FDG uptakes were larger on the 70 min scan images than on the 60 min scan images; the 60 min scans resembled Alzheimer's metabolic reduction area. Similarly the FDG uptakes were larger in the pons and vermis on the 60 min scan image than on the 70 min scan image. CONCLUSIONS: Regional FDG uptake is different depending on the time scanning starts after FDG injection, even with a 10 minute difference in start time and different scanning time may lead to misdiagnosis. It is important to standardize the start time of FDG PET after FDG injection in brain PET.     

Outcome in AIDS-related systemic non-Hodgkin lymphoma and leptomeningeal disease is not predicted by a CT brain scan

BACKGROUND AND PURPOSE: AIDS-related systemic non-Hodgkin lymphoma (ARL) remains a significant cause of morbidity and mortality in patients infected with the human immunodeficiency virus (HIV-1), and leptomeningeal disease in this setting has a dismal prognosis. We investigated the utility of brain CT in determining the outcome of leptomeningeal disease, despite MR imaging being the gold standard. MATERIALS AND METHODS: From a cohort of 9621 HIV-1-seropositive individuals, we identified those diagnosed with ARL in the highly active antiretroviral therapy (HAART) era who had both a lumbar puncture and central nervous system imaging using a CT brain scan at the time of initial diagnosis, and we compared survival parameters between those with and without leptomeningeal disease. RESULTS: In a cohort of 82 individuals with ARL treated in the era of HAART, we found that the survival of individuals with leptomeningeal disease defined as the presence of cells in the CSF was worse compared with that of other patients (P = .0026). However, when defined by the presence of abnormal enhancement or parenchymal lesions on a CT scan, the outcome was not significantly different. CONCLUSION: A CT brain scan appears not to offer additional prognostic information following a lumbar puncture in patients with ARL.     

Usefulness of 99mTc ethyl cysteinate dimer brain SPECT to detect abnormal regional cerebral blood flow in patients with acute carbon monoxide poisoning

99mTc ethyl cysteinate dimer (99mTc-ECD) brain single photon emission computed tomography (SPECT) was used to detect abnormal regional cerebral blood flow (rCBF) in patients with acute carbon monoxide (CO) poisoning. Ten patients with acute CO poisoning and no past histories of psychoneurological disorders were enrolled in this study. After oxygen treatment, all of the 10 patients were investigated using 99mTc-ECD brain SPECT and brain computed tomography (CT) scan. Brain CT scan findings were normal in all of the 10 patients. 99mTc-ECD brain SPECT showed the hypoperfusion lesions of the basal ganglia and brain cortex in five and seven patients, respectively. Only three of the 10 patients had normal 99mTc-ECD brain SPECT findings. This study suggests that, in comparison with brain CT scan, 99mTc-ECD brain SPECT is a better tool for the early detection of hypoperfusion brain lesions in acute CO poisoning in patients with normal brain CT findings.     

粟粒性脑结核病的MRI特征

目的 回顾性总结和分析粟粒性脑结核病的MRI表现特点。方法 对22例粟粒性脑内结核病患者的MRI特点，包括病灶大小，形态，分布情况及MR平扫与增强扫描的区别进行回顾性总结分析。结果 粟粒性脑结核多发生于大脑半球灰白质交界区，病灶直径≤3mm,平扫多不能显示，钒喷替酸葡甲胺（GD-DTPA）增强扫描呈明显结节状强化。结论 MR增强检查是早期发现粟粒性脑结核病的有效方法。     

Rapid spontaneous resolution and redistribution of acute subdural hematoma in a patient with chronic alcoholism: a case report

We report a case of a 54-year-old man who had documented traumatic acute subdural hematoma. He suffered from a transient episode of confusion and a follow-up CT scan of brain 6 h after the initial scan showed resolution and redistribution of the subdural hematoma. In this case report, we review the literature for the underlying pathophysiology of this uncommon phenomenon.     

Visualization of beta-amyloid plaques in a transgenic mouse model of Alzheimer's disease using MR microscopy without contrast reagents.

The visualization of beta-amyloid plaque deposition in brain, a key feature of Alzheimer's disease (AD), is important for the evaluation of disease progression and the efficacy of therapeutic interventions. In this study, beta-amyloid plaques in the PS/APP transgenic mouse brain, a model of human AD pathology, were detected using MR microscopy without contrast reagents. beta-Amyloid plaques were clearly visible in the cortex, thalamus, and hippocampus of fixed brains of PS/APP mice. The distribution of plaques identified by MRI was in excellent agreement with those found in the immunohistological analysis of the same brain sections. It was also demonstrated that image contrast for beta-amyloid plaques was present in freshly excised nonfixed brains. Furthermore, the detection of beta-amyloid plaques was achieved with a scan time as short as 2 hr, approaching the scan time considered reasonable for in vivo imaging.     

Multiple cerebral hydatid cysts

A 39-year-old woman was admitted to hospital with headaches, vomiting, psychic impairment and diplopia. Three hydatid cysts of the lung had been previously removed. An avascular mass in the left hemisphere with left-to-righ displacement of the anterior cerebral arteries was noted during a brain angioscintigraphy. A computed tomography (CT) brain scan showed two cystic lesions situated in the left-frontal and occipital regions. A CT abdominal scan showed multiple cysts in the liver, spleen and both kidneys. At operation, two brain cysts were totally extirpated without rupture. The definite pathological diagnosis was secondary hydatid cysts. The headaches, vomiting and diplopia were persistent in the post-operative period. Seven days after the operation, a CT brain scan showed an infratenrorial cyst. The patient rejected any surgical intervention.     

Scan time reduction in proton magnetic resonance spectroscopic imaging of the human brain.

A simple technique is described for scan time reductions in proton magnetic resonance spectroscopic imaging (MRSI) of the human brain. Scan time is reduced by approximately 35% while preserving spatial resolution by reducing the field of view (FOV) and number of phase-encoding steps in the transverse direction of the brain. A multislice MRSI of the brain is demonstrated which takes approximately 20 min with a square FOV, and 13 min with a reduced FOV. The signal-to-noise ratio (SNR) in the reduced FOV scan was measured to be 15% lower than that of the full FOV scan, which is close to the expected theoretical value of 19% based on the square root of the scan time. The method can be applied with any sequence, and requires minimal software and no hardware modifications. Scan time in MRSI is minimized in this method by using FOVs no larger than the dimensions of the object to be imaged. The method may also be combined with other fast MRSI techniques to provide further scan time reductions.     

Multiple cerebral hydatid cysts

A 39-year-old woman was admitted to hospital with headaches, vomiting, psychic impairment and diplopia. Three hydatid cysts of the lung had been previously removed. An avascular mass in the left hemisphere with left-to-right displacement of the anterior cerebral arteries was noted during a brain angioscintigraphy. A computed tomography (CT) brain scan showed two cystic lesions situated in the left-frontal and occipital regions. A CT abdominal scan showed multiple cysts in the liver, spleen and both kidneys. At operation, two brain cysts were totally extirpated without rupture. The definite pathological diagnosis was secondary hydatid cysts. The headaches, vomiting and diplopia were persistent in the post-operative period. Seven days after the operation, a CT brain scan showed an infratentorial cyst. The patient rejected any surgical intervention.     

Brain metastases detectability of routine whole body (18)F-FDG PET and low dose CT scanning in 2502 asymptomatic patients with solid extracranial tumors

As fluorine-18-fluorodesoxyglucose positron emission tomography/computed tomography ( (18)F-FDG PET/CT) is gaining wider availability, more and more patients with malignancies undergo whole body PET/CT, mostly to assess tumor spread in the rest of the body, but not in the brain. Brain is a common site of metastatic spread in patients with solid extracranial tumors. Gold standard in the diagnosis of brain metastases remains magnetic resonance imaging (MRI). However MRI is not routinely indicated and is not available for all cancer patients. Fluorine-18-FDG PET is considered as having poor sensitivity in detecting brain metastases, but this may not be true for PET/CT. The aim of our study was to assess the value of (18)F-FDG PET/CT in the detection of brain metastases found by whole body scan including the brain, in patients with solid extracranial neoplasms. A total of 2502 patients with solid extracranial neoplasms were studied. All patients underwent a routine whole body (18)F-FDG PET/CT scan with the whole brain included in the scanned field. Patients with known or suspected brain metastases were preliminary excluded from the study. Hypermetabolic and ring-like brain lesions on the PET scan were considered as metastases. Lesions with CT characteristics of brain metastases were regarded as such irrespective of their metabolic pattern. Lesions in doubt were verified by MRI during first testing or on follow-up or by operation. Our results showed that brain lesions, indicative of and verified to be metastases were detected in 25 out of the 2502 patients (1%), with lung cancer being the most common primary. Twenty three out of these 25 patients had no neurological symptoms by the time of the scan. The detection rate of brain metastases was relatively low, but information was obtained with a minimum increase of radiation burden. In conclusion, whole body (18)F-FDG PET/CT detected brain metastases in 1% of the patients if brain was included in the scanned field. Brain scanning as a part of whole body scan cannot replace routine imaging techniques, but in case of positive findings provides early and crucial information for further patient management, especially in asymptomatic patients.     

'Reverse crescent pattern' on SPECT brain perfusion scan in chronic subdural hematoma.

A SPECT brain perfusion scan was performed on a patient who had symptoms of dementia. The SPECT scan showed marked crescentic medial displacement of the left cerebral hemisphere ("reverse crescent pattern"), and mildly decreased cortical perfusion in the affected hemisphere. Crossed cerebellar diaschisis was not present. On x-ray CT, the underlying abnormality was found to be a unilateral chronic subdural hematoma causing a significant mass effect. A reverse crescent pattern without crossed cerebellar diaschisis on SPECT brain perfusion scan in patients with dementia may suggest the diagnosis of chronic subdural hematoma.     

Anterior choroidal artery infarction presenting as a progressive cognitive deficit

PURPOSE: The authors describe a patient in whom neuroimaging using Tc-99m HMPAO SPECT, F-18 fluorodeoxyglucose (F-18 FDG) coincidence imaging, and magnetic resonance imaging (MRI) identified an anterior choroidal artery infarction. Neuroimaging played a critical role in confirming this diagnosis, because the patient had symptoms of progressive cognitive decline and satisfied the National Institute of Neurological and Communicative Disorders and Stroke-Alzheimer's Disease and Related Disorders Association criteria for Alzheimer's disease (AD). METHODS: Tc-99m HMPAO brain SPECT was performed using a triple-head gamma camera. F-18 FDG scanning was obtained 40 minutes after intravenous injection of 5 mCi F-18 FDG using a coincidence camera. A brain MRI scan was performed using a 1.5-Tesla scanner. RESULTS: Tc-99m HMPAO SPECT showed focal hypoperfusion to the right parahippocampal cortex. F-18 FDG coincidence imaging showed a more extensive reduction in glucose metabolism compared with SPECT. The MRI scan confirmed the presence of a small segmental choroidal artery infarction. The Tc-99m HMPAO and F-18 FDG scans were not consistent with AD. CONCLUSIONS: This case illustrates the value of the regional cerebral blood flow SPECT for evaluating memory impairment in the elderly. Decreased regional cerebral blood flow to the posterior temporoparietal region is consistent with AD, whereas regional cerebral blood flow diminution in a vascular territory is consistent with vascular dementia. In this case, the patient was clinically diagnosed with AD, and SPECT was performed to establish the baseline regional cerebral blood flow before the cholinesterase inhibitor donepezil was administered. An infarction was diagnosed on the regional cerebral blood flow brain SPECT scan, which was later confirmed by MRI. Infarctions of the parahippocampal cortex may resuft in memory impairment, which can appear clinically similar to AD.     

Reproducibility of repeated measures of deuterium substituted [11C]L-deprenyl ([11C]L-deprenyl-D2) binding in the human brain

The purpose of this study was to assess the reproducibility of repeated positron emission tomography (PET) measures of brain monoamine oxidase B (MAO B) using deuterium-substituted [11C]L-deprenyl ([11C]L-deprenyl-D2) in normal subjects and to validate the method used for estimating the kinetic constants from the irreversible 3-compartment model applied to the tracer binding. Five normal healthy subjects (age range 23-73 years) each received two PET scans with [11C]L-deprenyl-D2. The time interval between scans was 7-27 days. Time-activity data from eight regions of interest and an arterial plasma input function was used to calculate lambda k3, a model term proportional to MAO B, and K1, the plasma to brain transfer constant that is related to blood flow. Linear (LIN) and nonlinear least-squares (NLLSQ) estimation methods were used to calculate the optimum model constants. A comparison of time-activity curves for scan 1 and scan 2 showed that the percent of change for peak uptake varied from -18.5 to 15.0% and that increases and decreases in uptake on scan 2 were associated with increases and decreases in the value of the arterial input of the tracer. Calculation of lambda k3 showed a difference between scan 1 and scan 2 in the global value ranging between -6.97 and 4.5% (average -2.1 +/- 4.7%). The average percent change for eight brain regions for the five subjects was -2.84 +/- 7.07%. Values of lambda k3 for scan 1 and scan 2 were highly correlated (r2 = 0.98; p < 0.0001; slope 0.955). Similarly, values of K1 showed a significant correlation between scan 1 and scan 2 (r2 = 0.61; p < 0.0001; slope 0.638) though the values for scan 2 were generally lower than those of scan 1. There was essentially no difference between the values of model constants calculated using the NLLSQ or LIN methods. Regional brain uptake of [11C]L-deprenyl-D2 varied between scan 1 and scan 2, driven by the differences in arterial tracer input. Application of a 3-compartment model to regional time-activity data and arterial input function yielded lambda k3 values for scan 1 and scan 2 with an average difference of -2.84 +/- 7.07%. Linear regression applied to values of lambda k3 from the LIN and NLLSQ methods validated the use of the linear method for calculating lambda k3.     

Steroid-induced suppression of gallium uptake in tumors of the central nervous system: concise communication

The effect of steroids given in greater than replacement doses on the gallium and technetium glucoheptonate brain scan is evaluated by comparing the relative sensitivity of both radiopharmaceuticals in patients both on and off steroids. The study shows a significant steroid effect on the sensitivity of 95% to 64% following steroids. Steroids did not significantly alter the sensitivity of the technetium glucoheptonate study. The superiority of the TcGH brain scan over the gallium citrate brain scan in the steroid population suggests a difference in the uptake mechanism for the two radiopharmaceuticals.     

Unusual finding of bronchopulmonary carcinoma through a pterygoid muscle metastasis. About a case

Bronchopulmonary cancer muscle metastases are uncommon, especially when they are visible. They can impact any muscle in the body, but the psoas, diaphragmatic, and paravertebral muscles have a clear advantage. We present a case of lateral pterygoid muscle metastasis of squamous cell carcinoma of the lung in a 70-year-old habitual smoker (40 packs per year) presents headaches more marked on the right and progressively worsening. A complementary brain MRI revealed a well-limited oval formation with irregular contours in hypo signal T1 hyper signal T2 heterogeneous, with area of central necrosis of the right pterygoid muscle, which was revealed to be a secondary location of bronchopulmonary malignancy after further examination (CT scan of the cervico-thoraco-abdomino-pelvic region, TEP scan, and biopsy). Moreover, muscle metastases are rarely revealing of primary cancer.     

Cystic meningioma: A case report with a literature review

Cystic meningiomas are very rare tumors of the central nervous system. We report the case of a 62-year-old female how presented headaches resistant to usual analgesics with behavior disorders. Cerebral CT scan showed a right frontal extra-axial tumor with firm and cystic component, brain MRI evoked the diagnosis, surgery removed the entire tumor and histological examination confirmed it. A cystic meningioma should not be omitted from the differential diagnosis of brain tumors with a cystic component and which clinical, radiological, histological and therapeutic features are discussed.