Intra-Ocular Lymphoma with and without CNS Involvement: Diagnosis and Follow-up a Report of 15 Cases Studied by MR

In order to assess the value of MRI in the diagnosis and follow-up of intra-ocular lymphoma, a rare form of primary non-Hodgkin's lymphoma of the central nervous system, we retrospectively reviewed fifteen patients.

All patients had ophthalmic investigations and 13 underwent ocular sampling. MR examinations of the brain and globes were performed in all cases and five patients underwent stereotactic brain biopsy. Six patients were treated with chemotherapy and/or radiotherapy, and nine with high-dose chemotherapy, followed by autologous bone marrow transplantation in five cases. MR follow-up was available in all cases.

All 15 patients had chronic uveitis which preceded the diagnosis and abnormal funduscopic findings. Three had a mild or severe neurologic deficit. Initial MRI showed brain lymphoma lesions in six cases and a choroido-retinal tumour in one. MR brain lesions were multiple in four cases. They appeared as contrast-enhanced infiltrating areas (n=11) or expansive masses (n=3); two lesions appeared as infiltrating high-signal T2 areas but were unenhanced on T1 with GdDTPA.

The diagnosis was based on vitrectomy in 11 cases and on stereotactic brain biopsy in four. Of the twelve lumbar punctures which were performed one was positive. Contrast enhancement disappeared during treatment in all cases, but isolated signal abnormalities persisted. The long-term outcome of such lesions in patients with an intact blood-brain barrier is not yet known. Ocular relapses occurred in 14 patients and CNS recurrences in four. Three patients died from CNS failure (n=1) or relapse (n=2), five are alive in partial remission, five are in complete remission and two died in remission from other causes. Follow-up ranges from 12 to 78 months (median 36 months).

MRI usually failed to detect intra-ocular lesions but identified clinically occult brain lesions and served to guide stereotactic brain biopsy when other samples were negative. MRI is the most sensitive follow-up method during treatment, even when the blood-brain barrier is intact.

[Paraplegia associated with intramedullary spinal cord and epidural abcesses, meningitis and spondylodiscitis (Staphylococcus aureus)]

INTRODUCTION

Intramedullary spinal cord abscesses are rare, frequently associated with meningitis, sometimes with epidural abscesses. They are frequently responsible for paraplegia. Staphylococcus aureus is the predominant organism. MRI shows an intramedullary collection giving a low-intensity signal on T1-weighted images with peripheral contrast uptake on enhanced TI-weighted studies and a high-intensity signal on T2-weighted images with generally extended adjacent medullary edema. They may be multiple.

CASE REPORT

We report the case of a man who presented meningitis with intramedullary and epidural abscesses. The number of the lesions did not allow chirurgical drainage. The paraplegia did not resolve despite appropriate antibiotic therapy.

CONCLUSION

Appropriate antibiotic therapy and early surgical drainage, if feasible, are key factors for better outcome and prognosis.

Cerebrovascular disease related to COL4A1 mutations in HANAC syndrome

BACKGROUND

COL4A1 mutations cause familial porencephaly, infantile hemiplegia, cerebral small vessel disease (CSVD), and hemorrhagic stroke. We recently described hereditary angiopathy with nephropathy, aneurysm, and muscle cramps (HANAC) syndrome in 3 families with closely localized COL4A1 mutations. The aim of this study was to describe the cerebrovascular phenotype of HANAC.

METHODS

Detailed clinical data were collected in 14 affected subjects from the 3 families. MRI and magnetic resonance angiography (MRA) were performed in 9 of them. Skin biopsies were analyzed by electron microscopy in affected subjects in the 3 families.

RESULTS

Only 2 of 14 subjects had clinical cerebrovascular symptoms: a minor ischemic stroke at age 47 years and a small posttraumatic hemorrhage under anticoagulants at age 48 years. MRI-MRA showed cerebrovascular lesions in 8 of 9 studied subjects (mean age 39.4 years, 21-57 years), asymptomatic in 6 of them. Unique or multiple intracranial aneurysms, all on the carotid siphon, were observed in 5 patients. Seven patients had a CSVD characterized by white matter changes (7/7) affecting subcortical, periventricular, or pontine regions, dilated perivascular spaces (5/7), and lacunar infarcts (4/7). Infantile hemiplegia, major stroke, and porencephaly were not observed. Skin biopsies showed alterations of basement membranes at the dermoepidermal junction associated with expansion of extracellular matrix between smooth vascular cells in the arteriolar wall.

CONCLUSION

The cerebrovascular phenotype in hereditary angiopathy with nephropathy, aneurysm, and muscle cramps syndrome associates a cerebral small vessel disease and a large vessel disease with aneurysms of the carotid siphon. It is consistent with a lower susceptibility to hemorrhagic stroke than in familial porencephaly, suggesting an important clinical heterogeneity in the phenotypic expression of disorders related to COL4A1 mutations.

MRI and FDG PET/CT findings in a case of probable Heidenhain variant Creutzfeldt-Jakob disease

Creutzfeldt-Jakob disease (CJD) is a neurodegenerative disease caused by the accumulation of a pathogenic isoform of a prion protein in neurons that is responsible for subacute dementia. The Heidenhain variant is an atypical form of CJD in which visual signs are predominant. This is a report of the case of a 65-year-old man with probable CJD of the Heidenhain variant, with topographical concordance between findings on magnetic resonance imaging (MRI) and 18F-fluorodeoxyglucose (FDG) photopenic areas on positron emission tomography (PET)/computed tomography (CT) for cortical parietooccipital lesions.

[Cerebral infarction related to intracranial radiation arteritis twenty-four years after encephalic radiation therapy]

We report a case of a resolutive late cerebral ischemic event, related to radiation induced vasculopathy of the left posterior cerebral artery, documented by MRI, situated in the irradiated volume 24 years before, for an astrocytome with malignant potential.

Reversible encephalopathy associated with cholesterol embolism syndrome: magnetic resonance imaging and pathological findings

We describe a patient found to have acute diffuse and reversible encephalopathy on magnetic resonance imaging (MRI) associated with cholesterol emboli syndrome (CES). The initial MRI showed extensive white matter, basal ganglia and cortical damage without evidence of brain infarction. Dramatic clinical and MRI improvement was observed with corticosteroids. Pathologically, cholesterol crystal emboli were found in the lumen of skin and brain arteries and were associated with varying degrees of inflammation of the arteriole wall. This case suggests that CES may be responsible for extensive, acute and reversible encephalopathy underlined by an inflammation of brain arteries.

[Intracerebral hematoma associated with reduced apparent diffusion coefficient mimicking acute stroke]

We report the case of a 67 year old patient admitted at our institution for acute onset of left hemiplegia. MRI was done 2 h 30 after symptom onset. Diffusion weighted images showed a hyperintense lesion in the right basal ganglia region with restricted apparent diffusion coefficient (ADC=428. 10(-6) mm(2)/s), a 50% decrease in value compared to the normal left side, consistent with acute ischemia. The lesion was hyperintense and moderately heterogeneous at FLAIR imaging, best seen on echo planar T2W images, with hypointense rim consistent with magnetic susceptibility artifact. The appearance and location of the lesion suggested the possibility of hematoma, which was confirmed at CT. Interpretation of ADC values must be performed in correlation with results at imaging including sequences sensitive to magnetic susceptibility artifacts such as echo planar T2*W and T2W sequences in order to exclude the possibility of underlying hematoma.

Long-term survival after gene therapy for a recurrent glioblastoma

A patient presenting with a recurrent glioblastoma (GBM) survived 3 years after suicide gene therapy and finally died of a disseminated breast cancer with no indication of tumor recurrence on MRI. Postmortem analysis showed no evidence of recurrence of the GBM, neither near the initial tumor localization nor in any other area of the brain. Such an evolution is unusual in the course of this disease and may suggest in this particular case a cure of the GBM.

[Exploration of the origin of supra-aortic arterial trunk: can MR angiography with gadolinium injection replace digital angiography?]

Ostial stenosis of the craniocervical vessels are frequently associated with carotid stenosis. Consequently, exploration of the aortic arch is necessary prior to carotid endarterectomy. Contrast-enhanced MR angiography (gRMA) could replace digital substraction angiography (DSA). The goal of this work was to evaluate gRMA for the detection of ostial stenosis of the craniocervical vessels. Twenty two patients with carotid stenosis > 50% on sonography examination prospectively underwent gRMA and DSA. We analyzed the overall quality of each gRMA and the degree of ostial stenosis of the craniocervical vessels (innominate, left carotid, subclavian and vertebral arteries). Thirteen gRMA examination was considered as good quality and 8 as adequate for diagnosis. There was significant correlation between gRMA and DSA for degree of stenosis (k = 0.82, p < 0.0001). gRMA tends to overestimate degree of ostial stenosis, especially for vertebral arteries. We conclude that gRMA is a promising tool but cannot yet be used as a stand-alone procedure for the evaluation of ostial stenosis of the craniocervical vessels.

Carotid artery stenosis: prospective comparison of CT, three-dimensional gadolinium-enhanced MR, and conventional angiography

PURPOSE

To prospectively compare gadolinium-enhanced magnetic resonance (MR) angiography and computed tomographic (CT) angiography with digital subtraction angiography (DSA) for use in detecting atheromatous stenosis and plaque morphology at the carotid bifurcation.

MATERIALS AND METHODS

Forty-four carotid arteries (in 22 patients) were analyzed by using CT angiography, enhanced MR angiography, and DSA. CT and enhanced MR angiograms were reconstructed with maximum intensity projection and multiplanar volume reconstruction. The following four features were analyzed: degree of stenosis on the basis of North American Symptomatic Carotid Endarterectomy Trial criteria, length of stenosis, luminal surface, and presence of ulcers.

RESULTS

There was significant correlation between CT angiography, enhanced MR angiography, and DSA for degree and length of stenosis. With enhanced MR angiography and CT angiography, degree of stenosis was underestimated in two of 44 cases. No case of overestimation with CT angiography was found. Severe internal carotid artery stenoses were detected with high sensitivity and specificity: 100% and 100%, respectively, with CT angiography; 93% and 100%, respectively, with enhanced MR angiography. Luminal surface irregularities were most frequently seen at CT angiography. With CT angiography and enhanced MR angiography, more ulceration was detected than with DSA.

CONCLUSION

There was a significant correlation between CT angiography, enhanced MR angiography, and DSA in evaluation of carotid artery stenosis. Enhanced MR angiography or CT angiography can be used to adequately evaluate carotid stenosis.

Extent of tumor-brain interface: a new tool to predict evolution of malignant gliomas

OBJECT

Tumor size is one of the features commonly used in oncology to predict disease evolution. However, for most primary brain tumors it is not predictive of outcome. Taking advantage of a gene therapy trial in which recurrences of glioblastoma were targeted with suicide genes, the authors developed a new parameter: the extent of tumor-brain interface--also called surface of tumor volume (STV)--to better describe three-dimensional conformation and the relationship between tumors and the surrounding normal tissue. Correlations between the STV and the usual clinical parameters were analyzed.

METHODS

Between 1995 and 1998, 16 patients presenting with recurrent glioblastomas were enrolled in this study. Preoperative magnetic resonance images were analyzed on a separate workstation; the interface between tumor and normal brain tissue was measured on each 3-mm-thick section to assess STV. The mean STV was 29.2 cm2, and the mean tumor volume (TV) was 23.8 cm3. The STV was significantly correlated with survival (Spearman test: r = -0.54, p = 0.03), but TV was not (Spearman test: r = -0.39, p = 0.15). A separate analysis of responding and nonresponding patients showed that, as expected, STV was negatively correlated with survival among nonresponding patients (p = 0.04), but that among responding patients there was a positive tendency between STV and survival.

CONCLUSIONS

These findings indicate that STV may be a useful tool for predicting the evolution of malignant glioma. Moreover, in future gene therapy trials in which such in situ approaches are used, increasing density and improved distribution of transfer cells should be taken into consideration as an important issue for efficacy.

False-negative diffusion-weighted MR findings in acute ischemic stroke

BACKGROUND AND PURPOSE

Lesions associated with acute stroke are often missed by diffusion-weighted imaging (DWI), suggesting that the sensitivity of this technique for detecting acute ischemic stroke may not be as high as initially thought. Our aim was to estimate the rate of false-negative DWI studies in patients with persistent neurologic deficit due to an ischemic stroke and to identify which stroke lesions are most likely to be missed by DWI.

METHODS

We reviewed MR images obtained within 48 hours after stroke onset in 139 patients admitted for symptoms consistent with ischemic stroke in whom the deficit lasted more than 24 hours. Cases of negative initial DWI findings with an ischemic lesion visible on follow-up MR studies and a final diagnosis of arterial ischemic stroke were analyzed in terms of delay between onset of symptoms and initial DWI (MR latency), size and vascular distribution of the lesions, and relationship to findings in patients with positive initial DWI results.

RESULTS

We found eight cases (5.8%) of false-negative initial DWI studies, of which four were positive on initial fluid-attenuated inversion recovery (FLAIR) imaging. Follow-up FLAIR/DWI showed a hyperintensity matching clinical presentation in all eight patients. The mean size of the lesion was 0.19 +/- 0.16 cm3. False-negative studies occurred more often in cases of stroke in the posterior (19%) than in the anterior (2%) circulation or when DWI was obtained within 24 hours after symptom onset. Of the six false-negative vertebrobasilar stroke lesions, five were located in the brain stem. In all, 31% of patients with vertebrobasilar ischemic stroke had a false-negative initial DWI study during the first 24 hours.

CONCLUSION

A false-negative DWI study is not uncommon during the first 24 hours of ischemic stroke. Vertebrobasilar stroke should therefore not be ruled out on the basis of early negative DWI, especially when symptoms persist and are suggestive of this diagnosis.

[3D-CT angiography with volume rendering technique in the intracerebral aneurysms]

PURPOSE

Many techniques of 3D reconstruction (MIP, SSD) permit a good evaluation of the circle of Willis in order to detect cerebral aneurysms. More recently, the advent in the clinical practice of a calculation algorithm (VRT) adapted to the workstations for images treatment seems to improve evaluation of the characteristics regarding these aneurysms.

MATERIALS AND METHODS

We report 4 cases with cerebral aneurysms studies with CT-angiography using the technique MIP and VRT.

RESULTS

The VRT, using the totality of image informations, allows a better understanding than MIP about the intracranial cerebral aneurysms including their constitution and 3D localization.

CONCLUSION

The VRT reconstruction permits to obtain quickly good quality and reproductive images, without relationship with threshold.

Intracranial aneurysm on CTA: demonstration using a transparency volume-rendering technique

We report an interesting transparency study using a volume-rendering technique applied to CT angiography in a patient with a sylvian aneurysm. On a single view, all the information required for the aneurysmal treatment could be analyzed. Comparison with maximum intensity projection and virtual endoscopy reconstructions was performed.

[The value of MRI for the diagnosis of meningeal hemorrhage during vasospasm]

Retrospectively, subarachnoidal hemorrhage can be misdiagnosed when the acute event did not bring the patient to medical attention, when clinical history is unclear and the CT scan is normal. Moreover, days after subarachnoid hemorrhage, cerebral vasospasm can result in neurological deficits that are indistinguishable from that produced by other causes of stroke. We report our experience with two patients who presented with symptoms of ischemia due to an arterial vasospasm that followed unrecognized rupture of an intracranial aneurysm. In both cases, CT scan failed to detect subarachnoid hemorrhage while MR detected the presence of signal changes in the subarachnoidal spaces associated with an ischemic stroke in one case. Neurological symptoms resolved completely after aneurysm treatment. MR can be a critical for the diagnosis of stroke secondary to vasospasm in order to prescribe an adapted treatment, avoid anticoagulant or thrombolytic therapy, and rapidly exclude the recently ruptured aneurysm to protect the patient from the risk of rebleeding.

[Diffusion MRI and cerebral ischemia. When to calculate the coefficient of diffusion?]

INTRODUCTION

There are two types of diffusion images: so-called "diffusion-weighted" images (DWI) and apparent diffusion coefficient (ADC) images. For certain authors, ADC mapping is crucial for interpreting diffusion images while for others the ADC map adds no further sensitivity or specificity compared with diffusion weighted images. The objective of this work was to determine those situations where ADC mapping modifies image interpretation.

MATERIAL AND METHODS

T2-weighted and diffusion-weighted (DIF) MRI sequences were acquired in 197 patients with suspected cerebral ischemia (< or = 48 hr). For each lesion (239 lesions in the 197 patients), we analyzed MRI interpretation with and without ADC mapping and compared the interpretations with the final diagnosis established on clinical data and complementary explorations.

RESULTS

We observed 3 groups. In group A (36% of the lesions), ADC mapping did not change image interpretation. This group was subdivided into 3 subgroups. A1: T2 and DIF weighted images are normal: no lesions and normal ACD map (n = 38 patients); A2: High intensity signal on T2 and low intensity signal on DIF: ischemic sequelae, ADC always increased (n = 32 lesions); A3: T2 normal and high intensity signal on DIF: hyper acute ischemia and ADC always decreased (n = 16 patients) In group B (high intensity signal on T2 and DIF, 54.5% of the lesions), ADC mapping changed the MRI interpretation: there was acute ischemia if the ADC was decreased (n = 113) and "pseudo-ischemic" lesions if the ADC was normal or increased (n = 17 patients). Group C was comprised of 23 lesions with a false negative ADC (9.5%). These lesions were always small recent ischemic lesions (< or = 5 mm) with a high intensity signal on DIF and a strictly normal ADC map.

CONCLUSION

ADC mapping was found to be useful in 54.5% of the lesions and should not be considered as solely a research tool but also as a useful tool for routine clinical practice.

A phase I/II study of herpes simplex virus type 1 thymidine kinase "suicide" gene therapy for recurrent glioblastoma. Study Group on Gene Therapy for Glioblastoma

Despite extensive surgery for glioblastoma, residual tumor cells always lead to relapse. Gene therapy based on retrovirus-mediated gene transfer of herpes simplex virus type 1 thymidine kinase (HSV-1 TK), which specifically sensitizes dividing cells to ganciclovir (GCV) toxicity, may help eradicate such cells. During glioblastoma surgery, HSV-1 TK retroviral vector-producing cells (M11) were injected into the surgical cavity margins after tumor debulking. After a 7-day transduction period, GCV was administered for 14 days. Safety was assessed by clinical and laboratory evaluations, and efficacy was assessed by MRI-based relapse-free survival at month 4 and by overall survival. Twelve patients with recurrent glioblastoma were treated without serious adverse events related to M11 cell administration or GCV. Quality of life was not negatively influenced by this treatment. Overall median survival was 206 days, with 25% of the patients surviving longer than 12 months. At 4 months after treatment, 4 of 12 patients had no recurrence; their median overall survival was 528 days, compared with 194 days for patients with recurrence (p=0.03 by the log rank test). One patient is still free of detectable recurrence, steroid free and independent, 2.8 years after treatment. Thus, brain injections of M11 retroviral vector-producing cells for glioblastoma HSV-1 TK gene therapy were well tolerated and associated with significant therapeutic responses. These results warrant further development of this therapeutic strategy in brain tumor, including recurrent glioblastoma.

Three-dimensional computerized tomography in the presurgical evaluation of Chiari malformations

Malformations of the cranio-cervical junction represent a complex entity, comprising neuro-meningeal and bone anomalies. Malformations of the central nervous system are nowadays easily explored using magnetic resonance imaging (MRI), while osseous malformations are classically assessed with standard radiographic techniques, which can give only incomplete information, and are often difficult to realize and analyse. We report a retrospective study of 10 patients with a Chiari malformation operated on in our department at La Salpêtrière hospital, between July 1995 and December 1996 (1 man, 9 women; mean of age: 35 years; postoperative median follow-up: 6 months; 70% of improvement and 20% of stabilisation), and we underline the interest of the systematic pre-operative realization of a 3D CT and angio-CT studies of the cranio-cervical junction. This examination offers advantages of: a precise analysis of the more complex osseous malformations; a study of the relationships between vascular and bony structures; a study of the relationships between neuraxis and spinal and cranial structures; and an optimal planning of the surgical procedure, adapted to the anatomical particularities of the patient.

Computerized tomographic angiography scan following carotid endarterectomy

The purpose of this study was to evaluate the role of computed tomographic angiography (CTA) for postoperative assessment of carotid endarterectomy (CE). Twenty carotid endarterectomies were performed and controlled by using (1) intraoperative angiography, (2) postoperative duplex scanning and CTA with multiprojection volume reconstruction (MPVR). Intraoperative angiographic controls were deemed satisfactory for all patients. In 12 patients, the postoperative morphological aspect was satisfactory with CTA and duplex scanning. In the eight remaining patients, CTA and/or duplex scanning revealed 12 abnormalities: 3 were equally visualized on CTA and duplex scanning, 6 only on CTA and 3 only on duplex scanning. CTA is a rapid and noninvasive technique allowing the surgeon to get informative and comparative data. It might be an interesting alternative to postoperative angiography.

Intracranial aneurysm: inner view and neck identification with CT angiography virtual endoscopy

We describe a virtual endoscopy tool applied on CT angiography acquisitions to analyze the neck and inner structures of an intracranial aneurysm. This technique, applied on a basilar artery aneurysm, accurately described its morphology and helped in making a choice between surgical and endovascular treatment.

Three-dimensional computed tomographic angiography in detection of cerebral aneurysms in acute subarachnoid hemorrhage

OBJECTIVE

Three-dimensional computed tomographic angiography (CTA) is a recently developed imaging modality. We demonstrate the value of this noninvasive method in replacing digital subtraction angiography (DSA) in the detection of aneurysms of the circle of Willis in patients with subarachnoid hemorrhage admitted to our institution.

METHODS

A helical acquisition was performed for computed tomographic scans obtained for 120 patients with a 1 mm per second table speed and a 1-mm collimation, 1:1 pitch. Axial source images were transferred on a console Advantage Windows workstation (General Electric, Milwaukee, WI) and CTA was obtained using maximum intensity projection reconstruction. All patients had undergone DSA of the circle of Willis (80 patients preoperatively and 40 postoperatively).

RESULTS

A total of 129 aneurysms were detected in 107 patients. Three-dimensional CTA disclosed nothing abnormal in 13 patients. Ninety-two patients sustained one aneurysm, 10 patients sustained two, 3 patients sustained three, and 2 patients sustained four. All results were confirmed by DSA. In two cases, aneurysms of the middle cerebral artery were defected by CTA but not by DSA. When using angiographic views, the aneurysm was always masked by a branch of the middle cerebral artery.

CONCLUSION

The sensitivity of three-dimensional CTA is comparable with that of DSA, and its specificity is 100%. Because CTA is simple, quick, noninvasive, and reliable, we think that it can eventually replace DSA.

MRI of pituitary adenomas in acromegaly

Adenomas causing acromegaly represent at least a quarter of pituitary adenomas. We studied 12 patients presenting with active acromegaly due to a pituitary adenoma with a 1.5 T superconductive MRI unit. All had T1-weighted sagittal and coronal sections before and after Gd-DTPA; six had coronal T2-weighted images. Surgical correlation was obtained in seven patients. Histologically, there were eight growth hormone (GH)-secreting and three mixed [GH and prolactin (PRL) secreting] adenomas, and one secreting GH, PRL and follicle-stimulating hormone. Macroadenomas (10) were more frequent than microadenomas (2). No correlation was found between serum GH and tumour size. There were nine adenomas in the lateral part of the pituitary gland; seven showed lateral or infrasellar invasion. Homogeneous, isointense signal on T1- and T2-weighted images was observed in six cases. Heterogeneous adenomas had cystic or necrotic components.

[Subarachnoid rupture of supratentorial dermoid cyst: CT and MRI aspects]

We report a case of ruptured subarachnoid dermoid cyst which was explored with both CT and MRI. This rare condition results from the accumulation of a large amount of fat with a characteristic aspect at-imaging. Rupture causes fat dissemination in the subarachnoid space. In most cases, CT or MRI can provide sure diagnosis of the tumor and of rupture.

[Is magnetic resonance the first indication in neurologic imaging?]

Various methods of neuroradiologie examination are described, with an emphasis on recent developments, in particular in CT scan (angioscan, spiral acquisition) and MRI. CT scan, which is the most accessible method, can answer most questions in intracerebral emergencies (trauma, vascular accidents, intracerebral hypertension ...). Outside the emergency setting, morphological study of the brain by MRI is much superior to that provided by CT scan and should be the first-line examination for investigation of suspected tumour, wite matter lesion.... This is even more evident in exploration of lesions of the posterior cranial fossa. In addition, introduction in the near future of functional MRI should lead to better knowledge of the relationship between cerebral lesions and functional zones. Ultrasonography remains a noninvasive and effective technique to seek lesions of the arteries supplying the brain. For spinal cord disorders, MRI is by far the examination of choice, except when contraindicated by the presence of cardiac pacemaker, metallic foreign bodies in the patient.