Walker-Warburg syndrome: diffusion MR imaging

A 5-month-old boy with Walker-Warburg syndrome is reported. On MR imaging a characteristic pontomesencephalic kink was evident. Collicular fusion, hydrocephalus, callosal dysgenesis, cobblestone lissencephaly, small cerebellar cysts, pontine and cerebellar hypoplasia, and bilateral subretinal hemorrhages were noted. ADC (apparent diffusion coefficient) maps of an echoplanar diffusion MR imaging sequence revealed an elevated diffusion pattern throughout the cerebral white matter, manifested with prominently high ADC values, ranging from 1.82 to 2.45 x 10(-3) mm2/s. This corresponded to prominent hypomyelination. On the other hand, ADC values of the lissencephalic cortex were normal, ranging from 0.95 to 0.97 x 10(-3)mm2/s. In addition, ADC values from the hypoplastic cerebellar hemispheres, and from the hypoplastic pons were normal.     

Diffusion MRI in the postmortem brain: case report

Postmortem brain of a ten-month-old child was examined by MR imaging, and diffusion MR imaging at the 12th hour after death in order to disclose the cause of death. There were basal ganglion lesions indicating a mitochondrial disorder. There was a prominent difference between the ADC values of the white matter (0.28+/-0.04 x 10(-3) mm2/s) and cortex (0.42+/-0.04 x 10(-3) mm2/s), and this was statistically significant (p< 0.0001). This difference suggested that in the postmortem brain the conditions in the white matter leading to restriction of movement of water molecules are more severe than that in the cortex.     

Diffusion-weighted mr in cerebral venous thrombosis

The diagnosis of cerebral venous thrombosis is often difficult both clinically and radiologically and until now there is no method available to predict if brain lesions, detected clinically and using conventional brain imaging methods, may lead to full recovery, as expected in vasogenic edema or ischemic infarcts and even a hematoma. New fast neuroimaging techniques such as diffusion-weighted imaging (DWI) are sensitive to different reasons of changes in local tissular water concentration thus giving further insight into the pathophysiological mechanism as well as prognosis of cerebral venous thrombosis. We report the cases of 18 consecutive patients with a diagnosis of cerebral venous thrombosis based on clinical and imaging criteria. All patients underwent magnetic resonance imaging (MRI) of the brain, which comprised isotropic diffusion-weighted MR. Diffusion-weighted MRI showed positive findings in 17/18 cases. In 7 cases the clot could be directly visualized as an area of hyperintensity in the affected vein on DWI. In 7 cases DWI showed areas of signal loss corresponding to hematomas. In 6 cases DWI showed changes in signal intensity that were more subtle. In 4 cases of superficial venous thrombosis, there were areas of decreased ADC values (0.65-0.79 x 10(-3) mm(2)/s) whereas in 2 cases of deep venous thrombosis, increased DWI intensities could be found that corresponded to both an increase and a decrease in ADC, corresponding to a coexistence of cytotoxic and vasogenic edemas. Diffusion-weighted MRI can demonstrate directly the presence of an intravenous clot in a select number of patients. It can also demonstrate early ischemic changes, and can differentiate conventional T2-weighted MR areas of cytotoxic from vasogenic edema.     

Diffusion MRI findings in neonatal brain abscess

In neonates and infants, bacterial brain abscess is rare, and the diffusion weighted MR imaging appearance of such abscesses has not been reported. We report the diffusion weighted MR findings of a brain abscess in a 25-day-old boy. The lesion initially had a large cystic component with some high-signal pyogenic material inside on diffusion-weighted (b=1000 sec/mm(2))images. The ADC value of this material was low (0.59 x 10(-3) mm(2)/sec), compared to the value from normal cerebellar parenchyma (0.78 x 10(-3) mm(2)/sec). The unusual initial appearance mimicked a cystic tumor. The lesion markedly decreased in size over 20 days after antibiotic therapy with persistent high-signal pyogenic material. In addition, at the initial presentation b=1000 sec/mm(2) images revealed high-signal changes in the brain parenchyma compressed by markedly dilated ventricles, consistent with ischemia. Also, ADC values of perilesional vasogenic edema (1.74 x 10(-3) mm(2)/sec), and that of transependymal resorption of CSF (1.56 x 10(-3) mm(2)/sec) were noted at the initial stage.     

Diffusion Magnetic Resonance Imaging in Intermediate Form of Maple Syrup Urine Disease

An 8-year-old boy with the intermediate variant of maple syrup urine disease is reported. On b = 1000 s/mm2 (heavily diffusion weighted) images of diffusion magnetic resonance imaging, there was symmetric high signal in the globus pallidus, mesencephalon, dorsal pons, and nucleus dentatus, consistent with restriction of the mobility of water molecules. Apparent diffusion coefficient (ADC) maps revealed low ADC values ranging from 0.42 to 0.56 x 10(-3) mm2/s in these regions, compared to those of apparently unaffected regions in the brain parenchyma ranging from 0.63 to 0.97 x 10(-3) mm2/s. It is suggested that the areas of increased signal (and low ADC values) are the result of dysmyelination as a reflection of disorganized tissue integrity.     

Diffusion-Weighted Magnetic Resonance Imaging in Superior Sagittal Sinus Thrombosis

BACKGROUND AND PURPOSE: Diffusion-weighted imaging (DWI) has shown high sensitivity in the diagnosis of acute arterial strokes. The pathophysiology of cerebral venous thrombosis with associated venous stroke appears to differ from that of arterial strokes. The purpose of this study was to describe DWI findings in venous strokes. METHODS: The authors reviewed 3 adults with superior sagittal sinus thrombosis who underwent DWI and magnetic resonance imaging within 24 hours of symptom onset. DWI was obtained at 1.5 T using the multishot echo planar technique (TR = 8000, TE = 97, field of view = 30 x 19 cm, slice thickness = 6.0 mm, interslice gap = 0.5 mm, matrix 128 x 128, NEX = 1). The diffusion gradients were applied in 3 orthogonal directions with 3 increasing b values (0-1000 s/mm2) to create average (trace) DWI images. Apparent diffusion coefficient (ADC) values were calculated on a pixel-by-pixel basis and displayed as ADC maps. RESULTS: DWI showed hyperintensities in patients 1 and 2 and hypointensity in patient 3 in corresponding to parenchymal lesions on conventional images. As compared to the homologous uninvolved location in the contralateral hemisphere, ADC values were decreased (0.53 x 10(-3) mm2/s [patient 1] and 0.68 x 10(-3) mm2/s [patient 2]) and increased (1.1 x 10(-3) mm2/s [patient 3]). The ADC ratio of the lesion in the involved to uninvolved side was 88% (patient 1), 81% (patient 2), and 120% (patient 3). CONCLUSION: Acute cerebral venous strokes may contain cytotoxic edema and/or vasogenic edema on DWI scans. DWI may be helpful in diagnosing cerebral venous thrombosis in cases with cryptic presentations.     

Colloid Cyst: Diffusion MR Imaging Findings

Colloid cysts usually have viscid gelatinous material or denser content. In an adult patient with a colloid cyst, diffusion magnetic resonance (MR) imaging was applied to detect its features with this sequence that if its viscous content may lead to a hyperintense appearance (decreased diffusion pattern) on b= 1000 sec/mm(2) images similar to epidermoids. The colloid cyst had hypointense signal on the b= 1000 sec/mm(2) image. The ADC map had more information that the ADC value of the cyst was 1.58 x 10(-3) mm(2)/sec. This value was apparently higher than that of normal cerebral parenchyma, and was apparently lower than that of CSF. These diffusion MR imaging features of the colloid cyst are consistent with an elevated diffusion pattern in contrast to epidermoids.     

Reversible splenial lesion with restricted diffusion in a wide spectrum of diseases and conditions

OBJECTIVE: Reversible lesion in the central area of the splenium of the corpus callosum (SCC) is a unique phenomenon occurring particularly in patients with encephalitis or encephalopathy and in patients receiving antiepileptic drugs (AED). We report MR imaging findings, clinical courses, and outcomes in eight patients with various diseases and conditions. MATERIALS AND METHODS: Eight patients with a reversible SCC lesion with transiently restricted diffusion were reviewed retrospectively. Diseases and conditions that were associated with a reversible lesion included epilepsy receiving AED (n=1), seizure from eclampsia receiving AED (n=1), mild infectious encephalitis (n=2), hypernatremia resulting in osmotic myelinolysis (n=1), and neoplasm (n=3) such as acute lymphocytic leukemia, spinal meningeal melanocytoma, and esophageal cancer. We evaluated MR imaging findings and clinical findings. RESULTS: Seven patients had isolated SCC lesions; one patient with osmotic myelinolysis showed additional parenchymal lesions. The reversible SCC lesion shape was oval (n=6) or extended (n=2). The mean apparent diffusion coefficient value of the splenial lesion was 0.40+/-0.16 x 10-3 mm2/s, ranging from 0.22 to 0.64 x 10-3 mm2/s. In a patient with osmotic myelinolysis, additional white matter lesions, shown as restricted diffusion, were revealed as not reversible on follow-up MR imaging. Neurological courses and outcomes were good in seven patients with isolated SCC lesions, but poor in one with osmotic myelinolysis. CONCLUSION: Reversible SCC lesion with restricted diffusion is apparent in a wide spectrum of diseases and conditions. Neurological courses and outcomes are good, particularly in patients with isolated SCC lesions. Knowledge of MR imaging findings and the associated spectrum of diseases and conditions might prevent unnecessary invasive examinations and treatments.     

Rasmussen's encephalitis: proton MR spectroscopy and diffusion MR findings

Rasmussen's encephalitis is a chronic inflammation of the brain that leads to progressive neurologic deficits. The condition has previously been studied by various imaging modalities including MR imaging and MR spectroscopy. We studied three patients presenting with Rasmussen's encephalitis by using proton MR spectroscopy, and diffusion-weighted MR imaging. In these patients, on diffusion-weighted MR imaging, mean apparent diffusion coefficient (ADC) value was 1.74 x 10(-3) mm(2)/sec within the parenchyma, apparently higher than that of the normal parenchyma (0.88 x 10(-3) mm(2)/sec) of a control group of five healthy subjects. Proton MR spectra were obtained with a TR value of 1,500 msec and differing TE values (135, 40, and 20 msec), and were compared with a control group of fourteen cases. In the affected regions of the brain, MR spectroscopy revealed decreased NAA, and increased Cho peaks associated with apparently decreased NAA/Cho, NAA/Cr ratios, and increased Cho/Cr ratios. Slightly increased mI peaks, and increased mI/NAA ratios were noted. A prominent lactate peak was noted in one of the patients.     

Does Reversal of Ischemia on Diffusion‐Weighted Imaging Reflect Higher Apparent Diffusion Coefficient Values?

This study investigated whether ischemia on diffusion-weighted imaging (DWI) that reverses has higher apparent diffusion coefficients (ADCs). A patient treated with thrombolytics was evaluated with serial magnetic resonance imaging studies before treatment, at 3 and 14 days and at 4 weeks. A 100.01-cm3 left frontoparietal stroke on baseline DWI was only 18.11 cm3 (18%) on 4-week fluid attenuated inversion recovery. The mean ADC was 7.43 x 10(-3) mm2/s in the 6 regions that reversed and 7.31 x 10(-3) mm2/s in the 6 regions that persisted (P < .036). With thrombolytic treatment, large ischemic lesions on DWI may reverse, and these areas display higher mean ADCs.     

Serial diffusion-weighted MR Imaging in delayed postanoxic encephalopathy. A case study

We report a case of delayed postanoxic encephalopathy (DPE) studied with serial diffusion weighted imaging five times in a one-year period along with apparent diffusion coefficient (ADC) map as well as ADC values of periventricular white matter. Compared to the normal value, the ADC values of the white matter were initially low on the three (0.68 +/- 0.08 x 10(-3) mm(2)/s) and seven-week images (0.67 +/- 0.08 x 10(-3) mm(2)/s) but gradually recovered to the normal range on the four, six, and twelve-month images (0.78 +/- 0.05, 0.80 +/- 0.05 and 0.87 +/- 0.11 x 10(-3) mm(2)/s, respectively). Among the several pathogenetic mechanisms associated with DPE, these serial changes may be consistent with cytotoxic edema, from apoptosis, triggered by hypoxia.     

Diffusion-weighted image in the study of brain tumors and peritumoral edema

The informative value of the technique of diffusion-weighted images (DWI) and diffusion maps was studied in diagnosing supratentorial tumors of the brain. Sixty four patients were examined. Among them there were 35 patients with glial brain neoplasms of varying malignancy [benign astrocytomas (asc) in 15 patients, anaplastic asc in 10, and glioblastomas in 10)], 15 patients with meningiomas, 5 with hydrocephalus, 9 with cerebral circulatory disorders. To obtain DWI, diffusion-weighted echo-planar impulse sequence was used. ADC was within (1.52 +/- 0.34) x 10(-3) mm2/sec for fibrillary astrocytomes. The anaplastic astrocytoma group showed variations in ADC values: ADC was higher in the contrasted part of the tumor than in the non-contrasted one and averaged (1.23 +/- 0.32) x 10(-3) mm2/sec. Glioblastomas were also noted for a higher variation in ADC that averaged (1.18 +/- 0.29) x 10(-3) mm2/sec. Meningiomas had a greater MR signal in response to DWI and low ADC values [(0.97 +/- 0.17) x 10(-3) mm2/sec]. Particular emphasis is laid on the study of different types of brain edema. ADC in the area of vasogenic (peritumoral), cytotactic (ischemic), and interstitial edema was (1.30 +/- 0.11) x 10(-3), (1.04 +/- 0.05) x 10(-3), and (1.91 +/- 0.1) x 10(-3) mm2/sec, respectively (p < 0.05) and sharply distinct in ADC maps.     

Serial brain imaging analysis of stroke-like episodes in MELAS

We report 2 patients of mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) and consider the pathophysiology of stroke-like lesions, using magnetic resonance imaging (MRI), diffusion-weighted imaging (DWI) on MRI, perfusion imaging on MRI, and 1H magnetic resonance spectroscopy (1H-MRS). In Patient 1, T2-weighted imaging (T2-WI) on MRI at onset and even at 44 days after onset of the stroke-like episode showed high intensity in left parietal, temporal, and occipital lobe lesions. In the temporal lobe lesion, the apparent diffusion coefficient (ADC) at 44 days after onset was higher (average: 1.219x10(-3)mm2/s) than that in a normal region (average: 0.796x10(-3)mm2/s). (1)H-MRS of the left parietal lobe lesion at the same day showed a decrease in N-acetylaspartate/(creatine+phosphocreatine) (NAA/Cr) (0.43) and a peak in lactate. 1H-MRS of the contralateral side at the same day showed NAA/Cr (1.57) and no peak in lactate. Thereafter, ADC gradually decreased and NAA/Cr gradually increased, and the peak in lactate disappeared in the lesion. In Patient 2, T2-WI at onset showed high intensity in bilateral occipital lobe lesions. In the left occipital lobe lesion, ADC at the same day was higher (1.082x10(-3)mm2/s) than that in a normal region (average: 0.841x10(-3)mm2/s). (1)H-MRS of the left occipital lobe lesion at the same day showed a decrease of NAA (3.0mM) and a peak in lactate (13.1mM) (measured by LCModel). In 1H-MRS of the normal left parietooccipital lobe at 4 months before onset, NAA was 7.6mM and there was no peak in lactate (0mM). Perfusion imaging at onset showed high intensity in bilateral occipital lobes, which indicated hyperperfusion in stroke-like lesions. Thereafter, ADC gradually decreased and the peak in lactate partially decreased, and the low concentration of NAA persisted (regardless of the partial recovery) in the lesion. These results suggest that the stroke-like episodes is related to vasogenic edema, hyperperfusion, and neuronal damage. Acute oxidative phosphorylation defect may have a crucial role in the pathophysiology of stroke-like episodes.     

Diffusion-weighted MR findings in isolated angiitis of the central nervous system (IACNS)

OBJECTIVES: To describe the diffusion-weighted MR (DWI) findings of isolated angiitis of the central nervous system (IACNS) and narrow the differential diagnosis. METHODS: The DWI findings of two IACNS patients. Apparent diffusion coefficient (ADC) values were measured in the abnormal lesions, and DWI and T2-weighted MR images were visually inspected. RESULTS: IACNS was diagnosed based on clinical history, MR findings and cerebral angiographic findings. DWI showed hyperintense lesions with heterogeneous ADC values (287-1359 x 10(-6) mm2/s), which indicate the coexistence of cytotoxic and vasogenic oedema. CONCLUSIONS: The findings suggest that the various stages of inflammatory process with ischaemia might exist in IACNS and allow a differentiation from the usual arterial ischaemic infarction. DWI with ADC map can be a useful non-invasive diagnostic test increasing specificity in the diagnosis of IACNS, combined with conventional MRI and cerebral angiography.     

表观扩散系数测量对多发性硬化各种病灶的评估价值

目的 探讨扩散加权成像(DWI)的定量指标表观扩散系数(ADC)值对多发性硬化(MS)各种病灶的评估价值.方法 60例临床确诊的复发缓解型MS患者做了常规MRI和DWI扫描,将直径>5 mm的病灶纳入研究对象,测量MS各种病灶平均ADC值,统计分析各种病灶ADC值是否有差别以及ADC值与临床扩展残疾功能状态量表(EDSS)评分之间的相关性.结果 (1)低信号与等信号病灶的ADC值分别为(127.5±9.3)×10-5、(95.7±6.3)×10-5 mm2/s,二者差异有统计学意义(F=55.90,P<0.05);结节性与环形强化病灶ADC值分别为(114.7±12.3)×10-5、(140.7± 11.0)×10-5mm2/s,二者差异有统计学意义(F=64.18,P<0.01);融合与分散病灶ADC值分别为(141.4±6.5)×10-5、(105.4±13.9)×10-5mm2/s,二者差异有统计学意义(t=9.04,P<0.01).(2)各种病灶的ADC值与EDSS评分之间没有明显相关性(r=0.35,P>0.05).结论 对DWI上各种病灶ADC值的定量分析在解释MS病灶的病理变化、监测其病程时有一定的价值.     

MR扩散加权成像对脑胶质瘤病理分级的临床研究

目的 探讨MR扩散加权成像对脑胶质瘤病理分级的临床应用价值.方法 选择经病理证实的30例脑胶质瘤患者入组研究,患者行MR扩散加权成像,测量肿瘤实质的表观扩散系数(ADC)、相对表观扩散系数(rADC)值,并进行统计学分析.结果 30例脑胶质瘤中低级别胶质瘤14例(Ⅰ级1例,为毛细胞型星形细胞瘤;Ⅱ级13例,其中星形细胞瘤11例.1例为术后复发,另室管膜瘤、少突胶质细胞瘤各一例),高级别胶质瘤16例(Ⅲ级11例,均为间变性星形细胞瘤,1例为术后复发;Ⅳ级5例,其中胶质母细胞瘤4例,室管膜瘤1例).低级别胶质瘤的ADC、rADC均值分别为(1.36±0.16)×10-3 mm2/s、1.76±0.23,高级别胶质瘤的ADC、rADC均值分别为(1.08±0.10)×10-3mm2/s、1.36±0.16,高级别与低级别胶质瘤的ADC、rADC均值比较差异有统计学意义(P<0.05).以低级别胶质瘤肿瘤实质ADC、rADC值的下限1.20×10.3mm2/s、1.53作为判断阈值,本组中诊断正确率分别为86.7%、83.3%.结论 ADC、rADC值对脑胶质瘤病理分级的诊断有较高的准确性.     

Apparent diffusion coefficient of pituitary macroadenoma evaluated with line-scan diffusion-weighted imaging

OBJECTIVE: The goal of this study was to evaluate the consistency of pituitary macroadenoma using apparent diffusion coefficient (ADC) with line-scan diffusion-weighted imaging (LSDWI). METHODS: Patients with pituitary macroadenoma (n=19) were studied prospectively. The LSDWI was performed using a maximum b factor of 1000 s/mm2. The consistency of macroadenoma was rated as soft, intermediate or hard at transsphenoidal surgery. The ADC values of tumors were compared with the tumor-consistency ratings. RESULTS: A soft consistency was found at surgery in 13 patients (mean ADC: 0.84+/-0.1x10(-3) mm2/s); an intermediate consistency was observed in six patients (mean ADC: 0.81+/-0.16x10(-3) mm2/s). No tumors of hard consistency were found. There was no significant difference in ADC values between tumors of soft consistency compared with tumors of intermediate consistency (P=0.37). CONCLUSIONS: A relationship between tumor consistency and the ADCs of soft and intermediate macroadenomas was not shown in this study using LSDWI.     

Multi-modal MRI in normal pressure hydrocephalus identifies pre-operative haemodynamic and diffusion coefficient changes in normal appearing white matter correlating with surgical outcome

Magnetic resonance techniques were used to investigate haemodynamic abnormalities and their consequences in normal pressure hydrocephalus (NPH) and to assess changes in these parameters following surgery. Eleven patients with NPH were studied pre- and post-operatively using perfusion and diffusion weighted imaging and compared with ten age-matched controls. Pre-operative periventricular relative cerebral blood volume (rCBV) was reduced in patients (0.76+/-0.11) compared with control (1.16+/-0.16, P<0.01). There was no difference between outcome groups and no change in haemodynamic parameters following surgery. The periventricular apparent diffusion coefficient (ADC) was elevated in the poor outcome group (1.67+/-0.3 x 10(-3) mm(2) s(-1)) compared with both controls (1.04+/-0.4 x 10(-3) mm(2) s(-1), P<0.05) and the good outcome group (0.99+/-0.3 x 10(-3) mm(2) s(-1), P<0.05) despite appearing normal on conventional imaging. In white matter hyperintensities (WMH), rCBV was reduced (0.70+/-0.12 vs. 1.00+/-0.10, P<0.01), and the ADC was increased (1.98+/-0.6 vs. 1.04+/-0.4 x 10(-3) mm(2) s(-1), P<0.05) compared with the same anatomical location in controls. As low rCBV and high ADC is characteristic of chronic infarction, the findings in WMH regions suggest they are irreversibly damaged. Normal appearing periventricular tissue rCBV was reduced, implying that significant haemodynamic consequences contribute to symptoms in NPH. The elevated pre-operative ADC of the same region, was correlated with poor outcome, and may, therefore, be useful in selecting patients for surgery.     

A case of cerebral venous thrombosis with reversible brain parenchymal lesions: usefulness of diffusion weighted imaging and measurement of apparent diffusion coefficient]

A 47-year-old man with a history of thrombophlebitis of his left leg for several years presented with a mild left hemiparesis and ipsilateral hypesthesia. Magnetic resonance imaging showed subacute thrombosis of the superior sagittal sinus and a cortical vein of the right cerebral hemisphere. A linear hyperintense area was found in the white matter of the right postcentral gyrus on T 2- and diffusion weighted axial imagings on the 7 days after the onset. The patient was treated conservatively, and his clinical course was uneventful. His neurological dysfunctions recovered within approximately three weeks after the onset. The white matter lesion in the right postcentral gyrus also disappeared one month later. The apparent diffusion coefficients (ADCs) in the white matter of the pre- and postcentral gyrus were measured bilaterally on the ADC mapping imaging. In the subacute stage, the ADC values in the white matter of the right pre- and postcentral gyrus were 0.50 x 10(-3) mm2/sec and 0.91 x 10(-3) mm2/sec, respectively. The %ADC indicating the ratio of ADC value of the lesion to that of the contralateral brain tissue was calculated. The %ADCs in the white matter of the pre- and postcentral gyrus were 64.9% and 124.5% respectively. In the chronic stage, the ADC values in the white matter of the right pre- and postcentral gyrus were 0.96 x 10(-3) mm2/sec and 0.99 x 10(-3) mm2/sec, and the %ADCs improved to 106.7% and 106.5% respectively. The lesions in the white matter of the right pre- and postcentral gyrus were reversible. The former was thought to be mainly ascribed to cellular edema and the latter was vasogenic edema. The present case showed when %ADC of the ischemic lesion in cerebral venous thrombosis was higher than 60%-70%, conservative therapy alone is sufficient effective for the improvement of neurological deficits.     

Diffusion‐Weighted Echo‐Planar MRI of the Brain with Calculated ADCs: A Useful Tool in the Differential Diagnosis of Tumor Necrosis from Abscess?

BACKGROUND AND PURPOSE: It was the aim of this study to evaluate whether brain abscesses could be distinguished reliably from necrotic brain tumors using diffusion-weighted imaging (DWI) with calculated apparent diffusion coefficients (ADCs). METHODS: The authors studied 27 lesions in 26 patients (21 tumors and metastases, 5 pyogenic brain abscesses, and 1 cerebral toxoplasmosis). DWI was obtained with a single-shot echo-planar imaging spin-echo sequence. ADCs were calculated for all images. RESULTS: ADCs (x 10(-3) mm2/s) measured in the necrotic parts of the tumors ranged from 2.94 (glioblastoma) to 1.51 (astrocytoma III). In the inflammatory lesions, ADCs ranged between 0.91 and 3.07 (cerebral toxoplasmosis and pyogenic abscess). The contrast-enhanced parts of the lesions showed ADC values from 0.77 (pyogenic abscess) up to 1.68 (glioblastoma). CONCLUSIONS: DWI with calculated ADC values does not allow the reliable differentiation of enhanced central necrotic intracranial lesions.