Diffusion-weighted MR imaging of early-stage Creutzfeldt-Jakob disease: typical and atypical manifestations

The Role of PET Imaging in Patients with Prion Disease: A Literature Review

Prion diseases are rare, rapidly progressive, and fatal incurable degenerative brain disorders caused by the misfolding of a normal protein called PrPC into an abnormal protein called PrPSc. Their highly variable clinical presentation mimics various degenerative and non-degenerative brain disorders, making diagnosis a significant challenge for neurologists. Currently, definitive diagnosis relies on post-mortem examination of nervous tissue to detect the pathogenic prion protein. The current diagnostic criteria are limited. While structural magnetic resonance imaging (MRI) remains the gold standard imaging modality for Creutzfeldt-Jakob disease (CJD) diagnosis, positron emission tomography (PET) using 18fluorine-fluorodeoxyglucose (18F-FDG) and other radiotracers have demonstrated promising potential in the diagnostic assessment of prion disease. In this context, a comprehensive and updated review exclusively focused on PET imaging in prion diseases is still lacking. We review the current value of PET imaging with 18F-FDG and non-FDG tracers in the diagnostic management of prion diseases. From the collected data, 18F-FDG PET mainly reveals cortical and subcortical hypometabolic areas in prion disease, although fails to identify typical pattern or laterality abnormalities to differentiate between genetic and sporadic prion diseases. Although the rarity of prion diseases limits the establishment of a definitive hypometabolism pattern, this review reveals some more prevalent 18F-FDG patterns associated with each disease subtype. Interestingly, in both sporadic and genetic prion diseases, the hippocampus does not show significant glucose metabolism alterations, appearing as a useful sign in the differential diagnosis with other neurodegenerative disease. In genetic prion disease forms, PET abnormality precedes clinical manifestation. Discordant diagnostic value for amyloid tracers among different prion disease subtypes was observed, needing further investigation. PET has emerged as a potential valuable tool in the diagnostic armamentarium for CJD. Its ability to visualize functional and metabolic brain changes provides complementary information to structural MRI, aiding in the early detection and confirmation of CJD.

Diffusion-Weighted Imaging is Key to Diagnosing Specific Diseases

This article reviews diseases for which persistent signal abnormalities on diffusion-weighted imaging are the key to their diagnosis. Specifically, updated knowledge regarding the neuroimaging patterns of the following diseases is summarized: sporadic Creutzfeldt-Jakob disease, neuronal intranuclear inclusion disease, and hereditary diffuse leukoencephalopathy with axonal spheroids-colony-stimulating factor receptors/adult-onset leukoencephalopathy with axonal spheroids and pigmented glia. In addition, their differential diagnoses; clinical manifestations; and pathologic, genetic, and imaging correlates are discussed.

Analysis of Chinese patients with sporadic Creutzfeldt-Jakob disease

Sporadic Creutzfeldt-Jakob disease (sCJD) is a rare, incurable, and fatal neurodegenerative disorder. The objective of this study was to describe the clinical features and survival time of Chinese sCJD patients, and to explore the associations between clinical data and survival. In this study, we analysed the clinical data of 21 sCJD patients in a tertiary care hospital and used all Chinese case material available from 152 patients with sCJD in literatures between 2008 and 2018. The mean age of onset of all 173 deceased patients was 61.44 year-olds (y), with the highest incidence in the population of 60 to 69 y. The most common manifestation at disease onset was progressive dementia. With the progression of the disease, the four main clinical symptoms and signs were developed, including myoclonus, visual or cerebella disturbance, pyramidal or extrapyramidal dysfunction, and akinetic mutism. Extrapyramidal symptoms were more frequently observed. The mean survival time was 7.34 months, and 82.10% of cases died within 1 year after disease onset. The follow-up showed that the survival time was longer and the myoclonus sign was more frequently presented in younger-onset sCJD patients. Patients with abnormalities only in cortical regions had a higher frequency of pyramidal dysfunction than patients having lesions in both cortex and basal ganglia. The findings of this study might provide some insight into the clinical characteristics of sCJD patients in China, but further studies could examine the presences of clinical features and survival time in patients with early age of onset in a prospective manner.

Gyriform restricted diffusion in adults: looking beyond thrombo-occlusions

Gyriform restricted diffusion (GRD) refers to hyperintense signal involving the cerebral cortex on diffusion-weighted images (DWI) with corresponding hypointensity on apparent diffusion coefficient (ADC) images. These changes are commonly seen following a vascular occlusion, reflecting the limitation of water molecule movement across cell membranes (restricted diffusion) due to the failure of Na⁺/K⁺-ATPase pumps (cytotoxic oedema). However, GRD can occur in several other neurological conditions as well. A thorough understanding of these conditions and their anatomic predilection plays a critical role in identifying and differentiating them from vascular thrombo-occlusion, with impact towards appropriate clinical management. This review highlights the less commonly encountered, non-stroke causes of GRD in adults with case-based examples. A tabulated chart of the patterns of cortical and subcortical involvement associated with these aetiologies is provided for a quick, pattern-based reference for daily radiological reporting.

Review of diffuse cortical injury on diffusion-weighted imaging in acutely encephalopathic patients with an acronym: "CRUMPLED"

Purpose

Acute encephalopathic syndromes can present a diagnostic challenge due to the wide range of possible etiologies, which also can have vastly different outcomes. The presence of diffuse cortical injury (DCI) on diffusion-weighted imaging (DWI) can help narrow the differential diagnosis. The aim of this review is to categorize the range of possible etiologies of DCI into a useful acronym, "CRUMPLED".

Methods

A review of the PACS system was completed to find a characteristic example of patients with DCI on DWI from different etiologies. The diagnosis was confirmed for each example via a subsequent review of the electronic medical record used to assess for data such as biopsy results, laboratory values, and clinical correlation. The electronic exhibit intends to demonstrate several sample cases of each letter within the acronym, and to demonstrate which types of DCI are potentially reversible or irreversible.

Findings/Discussion

The possible etiologies of DCI on DWI can be organized using the acronym "CRUMPLED": 'C' = Creutzfeldt-jakob disease, 'R' =  reversible cerebral vasoconstriction syndrome; 'U' = urea cycle disorders (hyperammonemia) and Uremia; 'M' = mitochondrial (cytopathy/encephalopathy); 'P' = prolonged seizure and posterior reversible encephalopathy (PRES); 'L' = laminar necrosis (hypoxic-ischemic encephalopathy) and liver disease (acute hepatic encephalopathy); 'E' = encephalitis (infectious meningoencephalitis); 'D' = diabetes mellitus (hypoglycemia). Other secondary imaging findings (outside of DWI) can be used to help differentiate between the aforementioned etiologies, such as the use of ADC maps, FLAIR imaging, intravenous contrast.

Conclusion

"CRUMPLED" is proposed as a convenient acronym for the categorization of a diverse range of acute etiologies associated with DCI on DWI, arising from varying degrees of cytotoxic edema. These etiologies can range from being potentially reversible (e.g. hyperammonemia or prolonged seizures) to irreversible (e.g. hypoxic-ischemic injury).

Case series of Creutzfeldt-Jakob disease in a third-level hospital in Quito

BACKGROUND

Creutzfeldt-Jakob disease is a rare and fatal neurodegenerative disorder that affects mammals and humans. The prevalence of this disease in the United States is 0.5 to 1 per million inhabitants. So far in Ecuador, we do not know what the prevalence or incidence is, and only one case report has been written.

CASE PRESENTATION

We present a case series of Creutzfeldt-Jakob disease in a third-level hospital in Quito. The average age of symptom onset in our patients was 58.8 years. The male to female ratio was 1:1. Two patients began with cognitive/behavioral symptoms, while 4 patients began with focal neurological signs; 1 case with ataxia, 2 with gait disorders and 1 with vertigo and headache. All of the patients had the clinical features established by the World Health Organization. In addition, the entire cohort was positive for the 14-3-3 protein in cerebrospinal fluid, and had high signal abnormalities in caudate and putamen nucleus in DWI and FLAIR IRM. Only in one case, did we reach a definitive diagnosis through a pathological study. All other cases had a probable diagnosis. In this series of cases, 6 out of 6 patients died. The average time from the onset of the symptoms to death in this cohort was 13 months.

CONCLUSION

This is the first report of a series of cases of Creutzfeldt-Jakob disease in Quito. Although definitive diagnosis must be histopathological, there are ancillary tests currently available that have allowed us to obtain a diagnosis of the disease.

Neuroimaging in Central Nervous System Infections

Radiologic imaging is often employed to supplement clinical evaluation in cases of suspected central nervous system (CNS) infection. While computed tomography (CT) is superior for evaluating osseous integrity, demineralization, and erosive changes and may be more readily available at many institutions, magnetic resonance imaging (MRI) has significantly greater sensitivity for evaluating the cerebral parenchyma, cord, and marrow for early changes that have not yet reached the threshold for CT detection. For these reasons, MRI is generally superior to CT for characterizing bacterial, viral, fungal, and parasitic infections of the CNS. The typical imaging features of common and uncommon CNS infectious processes are reviewed.

Beyond the embolus: "do not miss" diffusion abnormalities of ischaemic and non-ischaemic neurological disease

Abstract

Given the rapid evolution and technological advances in the diagnosis and treatment of acute ischaemic stroke (AIS), including the proliferation of comprehensive stroke centres and increasing emphasis on interventional stroke therapies, the need for prompt recognition of stroke due to acute large vessel occlusion has received significant attention in the recent literature. Diffusion-weighted imaging (DWI) is the gold standard for the diagnosis of acute ischaemic stroke, as images appear positive within minutes of ischaemic injury, and a high signal-to-noise ratio enables even punctate infarcts to be readily detected. DWI lesions resulting from a single arterial embolic occlusion or steno-occlusive lesion classically lateralise and conform to a specific arterial territory. When there is a central embolic source (e.g. left atrial thrombus), embolic infarcts are often found in multiple vascular territories. However, ischaemic disease arising from aetiologies other than arterial occlusion will often not conform to an arterial territory. Furthermore, there are several important entities unrelated to ischaemic disease that can present with abnormal DWI and which should not be confused with infarct. This pictorial review explores the scope and typical DWI findings of select neurologic conditions beyond acute arterial occlusion, which should not be missed or misinterpreted.

Teaching points

• DWI abnormalities due to acute arterial occlusion must be promptly identified.

• DWI abnormalities not due to arterial occlusion will often not conform to an arterial territory.

• Several important non-ischaemic entities can present on DWI and should not be confused with infarct.

Viral and Prion Infections of the Central Nervous System: Radiologic-Pathologic Correlation: From the Radiologic Pathology Archives

Viral infections of the central nervous system (CNS) range in clinical severity, with the most severe proving fatal within a matter of days. Some of the more than 100 different viruses known to affect the brain and spinal cord are neurotropic with a predilection for producing CNS infection. The host response to viral infection of the CNS is responsible for the pathophysiology and imaging findings seen in affected patients. Viral CNS infections can take the form of meningitis, encephalitis, encephalomyelitis, or, when involving the spinal cord and nerve roots, encephalomyeloradiculitis. In 1982, an infectious particle termed a prion that lacked nucleic acid and therefore was not a virus was reported to produce the fatal neurodegenerative disease Creutzfeldt-Jakob disease and related disorders. These prion diseases produce characteristic neuroimaging findings that are distinct from those seen in most viral infections. The clinical and imaging findings associated with viral CNS infection are often nonspecific, with microbiologic analysis of cerebrospinal fluid the most useful single test allowing for diagnosis of a specific viral infection. This review details the spectrum of viral CNS infections and uses case material from the archives of the American Institute for Radiologic Pathology, with a focus on the specific clinical characteristics and magnetic resonance imaging features seen in these infections. Where possible, the imaging features that allow distinction of these infections from other CNS inflammatory conditions are highlighted.

Imaging of Creutzfeldt-Jakob Disease: Imaging Patterns and Their Differential Diagnosis

Diagnosis of sporadic Creutzfeldt-Jakob disease (sCJD) remains a challenge because of the large variability of the clinical scenario, especially in its early stages, which may mimic several reversible or treatable disorders. The molecular basis of prion disease, as well as its brain propagation and the pathogenesis of the illness, have become better understood in recent decades. Several reports have listed recognizable clinical features and paraclinical tests to supplement the replicable diagnostic criteria in vivo. Nevertheless, we lack specific data about the differential diagnosis of CJD at imaging, mainly regarding those disorders evolving with similar clinical features (mimicking disorders). This review provides an update on the neuroimaging patterns of sCJD, emphasizing the relevance of magnetic resonance (MR) imaging, summarizing the clinical scenario and molecular basis of the disease, and highlighting clinical, genetic, and imaging correlations in different subtypes of prion diseases. A long list of differential diagnoses produces a comprehensive pictorial review, with the aim of enabling radiologists to identify typical and atypical patterns of sCJD. This review reinforces distinguishable imaging findings and confirms diffusion-weighted imaging (DWI) features as pivotal in the diagnostic workup of sCJD, as these findings enable radiologists to reliably recognize this rare but invariably lethal disease. A probable diagnosis is justified when expected MR imaging patterns are demonstrated and CJD-mimicking disorders are confidently ruled out. ^©RSNA, 2017.

Brain CT and MRI: differential diagnosis of imaging findings

Following a traditional approach, in Chapters 5 and 14-29 in the previous volume, diverse brain diseases are listed and their imaging findings described in detail. In this chapter the approach is from the imaging finding to the disease: for instance, what list of diseases can give rise to a contrast-enhancing mass in the cerebellopontine angle? Imaging findings that are reviewed in succession include the location of the lesion, its multiplicity and symmetry, its volume, ranging from atrophy to mass effect, its homogeneity, its density, measurable by computed tomography (CT), its appearance on T1, T2, and diffusion magnetic resonance imaging (MRI), and, finally, its characteristics after the infusion of intravenous contrast. A differential diagnosis for each finding is provided. While the approach adopted in this chapter is unconventional, we hope that it will be most helpful to anyone reading images. Furthermore, it could serve as the basis to create or complete image databases to guide in the interpretation of brain CT and MRI.

Magnetic resonance imaging findings in probable Creutzfeld-Jacob disease: comparison with electroencephalography and cerebrospinal fluid characteristics

BACKGROUND

Creutzfeld-Jacob disease (CJD) is a rare, progressive disease that has a vast clinical manifestation range. Cranial magnetic resonance imaging (MRI), electroencephalography (EEG), and measurement of 14-3-3 in cerebrospinal fluid (CSF) may offer a pragmatic approach in the diagnosis of CJD as an alternative to histopathological confirmation.

PURPOSE

To present the symptoms and signs of the CJD patients in regard to radiological and neurophysiological findings.

MATERIAL AND METHODS

We collected all cases with the diagnosis of probable CJD admitted to our neurology department between June 2010 and June 2014. The medical records and laboratory data, clinical features, results of MRI (including diffusion weighted images), EEG and CSF evaluations, and other laboratory data to exclude other possible diagnoses were recorded. None of the patients underwent biopsy or autopsy for histological diagnosis.

RESULTS

Of 20 patients, 11 (55%) were men and nine (45%) were women. The mean age at disease onset was 60.0 ± 9.5 years (age range, 47-80 years). All patients without exception had characteristic abnormalities in DWI and/or FLAIR on admission, about 4 months after the initial symptom. Periodic complexes on EEGs characteristic for CJD were detected only in 10 patients (50%) on admission and in 13 patients (65%) during disease course. Out of 14 patients who underwent CSF examination, 11 (78.5%) were positive for 14-3-3 protein.

CONCLUSION

Although the definite diagnosis of CJD is made histopathologically, we aimed to discuss the value of magnetic resonance imaging in the diagnosis of CJD in respect to EEG findings and protein 14-3-3 levels in CSF.

MRI in central nervous system infections: A simplified patterned approach

Recognition and characterization of central nervous system infections poses a formidable challenge to the neuro-radiologist. Imaging plays a vital role, the lesions typically being relatively inaccessible to tisue sampling. The results of an accurate diagnosis are endlessly rewarding, given the availability of excellent pharmacological regimen. The availability of numerous magnetic resonance (MR) sequences which provide functional and molecular information is a powerful tool in the hands of the radiologist. However, the plethora of sequences and the possibilities on each sequence is also intimidating, and often confusing as well as time consuming. While a large number of reviews have already described in detail the possible imaging findings in each infection, we intend to classify infections based on their imaging characteristics. In this review we describe an algorithm for first classifying the imaging findings into patterns based on basic MR sequences (T1, T2 and enhancement pattern with Gadolinium), and then sub-classify them based on more advanced molecular and functional sequences (Diffusion, Perfusion, Susceptibility imaging, MR Spectroscopy). This patterned approach is intended as a guide to radiologists in-training and in-practice for quickly narrowing their list of differentials when faced with a clinical challenge. The entire content of the article has also been summarised in the form of flow-charts for the purpose of quick reference.

Sporadic Creutzfeldt-Jacob Disease: An 8-Year Experience from a Single Center in Turkey

INTRODUCTION

Our aim was to conduct a retrospective review to demonstrate the clinical, radiological, and electrophysiological features of patients with sporadic Creutzfeldt-Jacob disease (sCJD).

METHOD

A total of 10 patients (5 female and 5 male, with a mean age of 45 years from a range of 40 to 67 years) out of 8.259 adult patients hospitalized from January 2000 to December 2008 were diagnosed with sCJD.

RESULTS

Eight of the patients were diagnosed on the basis of clinical, radiological, electroencephalography (EEG), and cerebrospinal fluid (CSF) findings. Two other patients also had a pathological diagnosis. The most common signs and symptoms were behavioral disturbances, movement disorders, cognitive decline, myoclonus, psychosis, focal neurological deficit, and aphasia. Nine of the patients had periodic sharp wave discharges on EEG. Seven patients were positive for the 14.3.3 protein in the CSF. Five patients had pulvinar signs-a bilateral increased signal in the pulvinar thalami-on cranial magnetic resonance imaging. Eight patients were diagnosed with probable sCJD; two were diagnosed with definite sCJD. All of the patients died as a result of the disease within 24 months after the onset of symptoms.

DISCUSSION

sCJD should be considered in the diagnosis of patients who present with rapidly progressive dementia. Clinical and radiological data appear to be sufficient for the diagnosis. However, detailed molecular examinations of the subtypes of the disease may be required for early diagnosis of cases given the wide spectra of CJD.

Neuroimaging of rapidly progressive dementias, part 2: prion, inflammatory, neoplastic, and other etiologies

Most dementias begin insidiously, developing slowly and generally occurring in the elderly age group. The so-called rapidly progressive dementias constitute a different, diverse collection of conditions, many of which are reversible or treatable. For this reason, accurate identification and assessment of acute and subacute forms of dementia are critical to effective treatment; neuroimaging aids greatly in narrowing the diagnosis of these conditions. This second installment of a 2-part review of rapidly progressive dementias examines the use of imaging in an assortment of other etiologies in the differential diagnosis, from prion disease and neoplastic-related conditions to rare metabolic and other conditions such as Wernicke encephalopathy. In these clinical conditions, MR imaging has the potential to narrow this broad differential diagnosis and, at times, can definitively aid in the diagnosis of certain conditions on the basis of typical imaging patterns.

Imaging of prion diseases

Prion diseases are caused by self-replicating proteins that induce lethal neurodegenerative disorders. In the last decade, the understanding of the different clinical, pathological, and neuroimaging phenotypes of this group of disorders has evolved paralleling the advances in prion molecular biology. From an imaging standpoint, the implementation of diffusion-weighted imaging in routine practice has markedly facilitated the detection of prion diseases, especially Creutzfeldt-Jakob. Less frequent prion-related disorders, including genetic diseases, may also benefit from progresses in the field of quantitative diffusion-weighted imaging, MR spectroscopy or molecular imaging. Herein, we present a review of the neuroimaging features of the prion disorders known to affect humans emphasizing the important contribution of MRI in the diagnosis of this group of disorders.

Diffusion MR imaging for monitoring treatment response

The objective of this article was to emphasize the use of diffusion-weighted imaging in the diagnosis and follow-up of several major disease contexts, as established in recent literature. In some of these diseases the diffusion changes are correlated with the clinical deficit and are potentially useful for early diagnosis and longitudinal evaluation, as well as in the context of pharmacologic trials. Diffusion magnetic resonance is a major advance in the continuing evolution of MR imaging. It provides contrasts and characterization between tissues at a cellular level that may imply differences in function as well as framework and have contributed to a better understanding of the pathophysiological mechanisms of several diseases.

Diffusion imaging in brain infections

Diffusion-weighted magnetic resonance imaging (DWI) provides image contrasts that are different from conventional magnetic resonance techniques. DWI is particularly sensitive for detecting acute ischemic stroke, but it also has many other clinical applications, including the evaluation of central nervous system (CNS) infections. This article addresses the role of DWI in the differential diagnosis of CNS infections, and discusses the most common DWI findings for each type of infection.

Direct determination of ECD in ECD Kit: a solid sample quantitation method for active pharmaceutical ingredient in drug product

Technetium-99m ethyl cysteinate dimer (Tc-99m-ECD) is an essential imaging agent used in evaluating the regional cerebral blood flow in patients with cerebrovascular diseases. Determination of active pharmaceutical ingredient, that is, L-Cysteine, N, N'-1,2-ethanediylbis-, diethyl ester, dihydrochloride (ECD) in ECD Kit is a relevant requirement for the pharmaceutical quality control in processes of mass fabrication. We here presented a direct solid sample determination method of ECD in ECD Kit without sample dissolution to avoid the rapid degradation of ECD. An elemental analyzer equipped with a nondispersive infrared detector and a calibration curve of coal standard was used for the quantitation of sulfur in ECD Kit. No significant matrix effect was found. The peak area of coal standard against the amount of sulfur was linear over the range of 0.03-0.10 mg, with a correlation coefficient (r) of 0.9993. Method validation parameters were achieved to demonstrate the potential of this method.

Cortical restricted diffusion as the predominant MRI finding in sporadic Creutzfeldt-Jakob disease

Creutzfeldt-Jakob disease is a rare and fatal neurodegenerative disorder with MR findings predominantly limited to the grey matter of the cortex and the basal ganglia. Sporadic Creutzfeldt-Jakob disease can produce a spectrum of MR imaging findings of the brain, most notably on DWI and FLAIR sequences. Involvement of the basal ganglia and neocortex is the most common finding, but isolated involvement of the cortex can also be seen. We describe the clinical history and MRI findings of three patients with sporadic Creutzfeldt-Jakob disease confirmed by brain biopsy or autopsy and review the literature of imaging manifestations of this disease.

Emergent neuroimaging of intracranial infection/inflammation

Infectious and inflammatory processes of the intracranial compartment often result in acute clinical presentations. The possible causes are legion. Clues to the diagnosis involve clinical presentation, laboratory analysis, and neuroimaging. This article reviews some of the salient factors in understanding intracranial infection/ inflammation, including pathophysiology and neuroimaging protocols/findings, and provides some examples and a few "pearls and pitfalls."

Creutzfeldt-Jakob disease with PRNP G114V mutation in a Chinese family

BACKGROUND

Recent evidence has shown clinical phenotypic heterogeneity of inherited prion diseases, even between patients harbouring the same mutation in the PRNP gene.

OBJECTIVE AND METHODS

We collected clinical data from a Chinese family with autosomal dominant dementia and screened the PRNP gene on 28 living members. A stereotactic biopsy of the right frontal lobe of the proband was performed.

RESULTS

The family comprised four affected individuals within two successive generations. The age of onset was in 30 or 40 s, and the duration was about 2-3 years. Clinical features of the affected members included neuropsychiatric disturbances, progressive dementia and extrapyramidal symptoms. Immunostaining for prion protein showed fine granular deposits of PrP(sc) in the neuropil. The PRNP gene analysis demonstrated a heterozygous G114V mutation in 15 family members. The proband was diagnosed as familial Creutzfeldt-Jakob disease (fCJD).

CONCLUSION

This study strengthens the linkage of the G114V mutation to CJD. It supports the worldwide distribution of fCJD despite differences in genetic background.

Enhanced detection of diffusion reductions in Creutzfeldt-Jakob disease at a higher B factor

BACKGROUND AND PURPOSE

Diffusion-weighted imaging (DWI) is sensitive to the cerebral manifestations of human prion diseases. The magnitude of diffusion weighting, termed "b factor," has only been evaluated at the standard b = 1000 s/mm(2). This is the first rigorous evaluation of b = 2000 s/mm(2) in Creutzfeldt-Jakob Disease (CJD).

MATERIALS AND METHODS

We compared DWI characteristics of 13 patients with CJD and 15 healthy controls at b = 1000 s/mm(2) and b = 2000 s/mm(2). Apparent diffusion coefficients (ADC) were computed and analyzed for the whole brain by voxel-wise analysis (by SPM5) as well as in anatomically defined volumes of interest (by FSL FIRST).

RESULTS

Measured ADC was significantly lower (by approximately 5%-15%) at b = 2000 s/mm(2) than at b = 1000 s/mm(2) and significantly lower in patients than in controls. The differences between patients and controls were greater and more extensive at b = 2000 s/mm(2) than at b = 1000 s/mm(2) in the expected regions (thalamus, putamen, and caudate nucleus).

CONCLUSIONS

Because higher b factors change the absolute value of observed ADC, as well as lesion detection, care should be taken when combining studies using different b factors. While the clinical application of high b factors is currently limited by a low signal intensity-to-noise ratio, it may offer more information in questionable cases, and our results confirm and extend the central role of diffusion imaging in human prion diseases.

[Creutzfeldt-Jakob disease: magnetic resonance imaging findings]

OBJECTIVES

To show the usefulness of magnetic resonance imaging in the diagnosis of Creutzfeldt-Jakob disease (CDJ) and to familiarize the radiologist with the characteristic imaging findings for this entity.

MATERIAL AND METHODS

We retrospectively studied six patients diagnosed with Creutzfeldt-Jakob disease at our center from 2004 through 2008. We reviewed the clinical, laboratory, electroencephalographic, and imaging findings in each case, and we correlated the results with the autopsy findings or with the World Health Organization's criteria for CDJ in the cases for which histopathological data were not available.

RESULTS

Of the six patients diagnosed with CDJ, autopsy findings confirming the diagnosis were available in four patients and the other two patients fulfilled the World Health Organization's criteria for the diagnosis (one classified as probable and other as possible). In all cases, we observed characteristic alterations on magnetic resonance imaging at the level of the cortex and/or basal ganglia. These alterations were detected in the initial clinical phases.

CONCLUSIONS

Radiologists should be familiar with the characteristic alterations of CDJ at magnetic resonance imaging to enable the early diagnosis of this entity.