Pyruvate: An in vivo marker of cestodal infestation of the human brain on proton MR spectroscopy

Proton and Multinuclear Spectroscopy of the Pediatric Brain

Magnetic resonance spectroscopy (MRS) is a valuable adjunct to structural brain imaging. State-of-the-art MRS has benefited greatly from recent technical advancements. Neurometabolic alterations in pediatric brain diseases have implications for diagnosis, prognosis, and therapy. Herein, the authors discuss MRS technical considerations and applications in the setting of various pediatric disease processes including tumors, metabolic diseases, hypoxic/ischemic encephalopathy/stroke, epilepsy, demyelinating disease, and infection.

Magnetic resonance imaging as an adjunct to computed tomography in the diagnosis of pulmonary Hydatid cysts

Introduction:

Although pulmonary hydatid cysts can be diagnosed on computed tomography (CT), sometimes findings can be atypical. Other hypodense infective or neoplastic lesions may mimic hydatid cysts. We proposed that magnetic resonance imaging (MRI) may act as a problem-solving tool, aiding the definite diagnosis of hydatid cysts and differentiating it from its mimics. The aim of this study is to assess the findings of pulmonary hydatid cysts on CT and MRI and the additional contribution of MRI in doubtful cases.

Materials and Methods:

This is a retrospective study of 90 patients with suspected hydatid cysts. CT and MRI findings were noted and role of MRI in diagnosing hydatid cysts and its mimics was studied. Descriptive statistics for CT findings and sensitivity and specificity of MRI were calculated using surgery or histopathology as gold standard.

Results:

Of the 90 patients with suspected pulmonary hydatid cysts, there were 52 true-positive and 7 false-positive cases on CT. Commonest CT finding was unilocular thick-walled cyst. In the 26 patients who had additional MRI, based on T2-weighted hypointense rim or folded membranes, accurate preoperative differentiation of 14 patients with hydatid cysts from 10 patients with alternate diagnosis was possible. There was one false-positive and one false-negative case on MRI.

Conclusion:

Although hydatid cyst can be diagnosed on CT on most occasions, sometimes there are challenges with certain mimics and atypical appearances. T2-weighted MRI can act as a problem solving tool to conclusively diagnose hydatid cyst or suggest an alternate diagnosis.

Brain MRI Findings in Coenurosis: A Helminth Infection

BACKGROUND AND PURPOSE

Parasitic neuroinfections in humans have etiological agents spanning a broad spectrum from unicellular (protozoan) to multicellular helminthic (metazoan) organisms. Cerebral coenurosis is a rare cestodal helminthic infection caused by Taenia multiceps. The neuroimaging features of this entity were reviewed to discern an imaging phenotype.

METHODS

Retrospective analysis was performed on 6 cases of cerebral coenurosis, whose diagnoses were confirmed by histopathology. The clinical, imaging, and histopathological features were recorded for analysis.

RESULTS

Clinical expressions included focal neurological deficit due to mass effect (n = 4), intraventricular obstruction with features of raised intracranial tension (n = 1), headache (n = 3), seizures (n = 3), and incidental lesions (n = 1). One patient presented with recurrence 1 year after surgical excision. Neuroimaging revealed cystic thin-walled lesions with clustered eccentric internal nodules corresponding to the plenitude of protoscolices of the tapeworm. Three of the lesions showed a multilocular cystic morphology. Spectroscopic metabolite signature of alanine and succinate commensurate with the parasitic etiology was remarkable in the lesions. Enhancement and edema inversely correlated with the signal suppression on fluid-attenuated inversion recovery (FLAIR) imaging. The lesions had a predominantly juxtacortical distribution.

CONCLUSIONS

In an appropriate clinical setting, a cystic lesion with clustered eccentric internal nodular foci ought to raise the suspicion of this rare infection. Magnetic resonance spectroscopic signature of succinate and alanine, if present, further strengthens the likelihood of coenurosis. Signal characteristics, wall enhancement, and perilesional edema may vary, possibly determined by the stage in the evolution of the parasite.

[Cerebral hydatid cysts in children: about 15 cases]

L’objectif de notre étude est d’illustrer l’intérêt de l’imagerie en coupe (TDM, IRM) dans le diagnostic positif et le suivi post-thérapeutique du kyste hydatique cérébral chez l’enfant et de mettre en lumière les particularités et les difficultés rencontrées dans la prise en charge de la localisation cérébrale de cette affection, par notre expérience basée sur 15 cas de kyste hydatique cérébral de l’enfant. Il s’agit d’une étude rétrospective de 15 cas d’hydatidose cérébrale de l’enfant colligés sur une période de 10 ans. La TDM cérébrale en coupes axiales de 5 mm d’épaisseur sans et avec injection de produit de contraste a été réalisée chez 15 patients. L’IRM encéphalique a été réalisée en séquences pondérées en T1 et en T2 chez un patient dans les trois plans de l’espace sans injection de Gadolinium. L’âge moyen de nos patients était de 9 ans. La symptomatologie clinique était dominée par le syndrome d’hypertension intracrânienne. Le kyste hydatique était solitaire et se situait au niveau de l’étage sus-tentoriel avec un important effet de masse sur le système ventriculaire et la ligne médiane dans la majorité des cas. Tous nos patients ont été opérés et l’évolution était favorable dans tous les cas. La TDM représente l’examen de choix pour le diagnostic et le suivi postopératoire du kyste hydatique cérébral. L’IRM trouve son intérêt essentiellement dans le diagnostic des formes multiples et des formes atypiques permettant une planification thérapeutique plus adaptée.

Our study aimed to highlight the role of cross sectional imaging techniques (CT, MRI) in positive diagnosis and post-therapeutic follow-up of cerebral hydatid cysts in children as well as to describe the peculiarities and the difficulties encountered in the management of these cysts based on our experience about 15 cases. We conducted a retrospective study of 15 cases of cerebral hydatidosis in children whose data were collected over a period of 10 years. CT scan of the brain with 5 mm slice thickness without and with injection of contrast product was performed in 15 patients. One patient underwent brain MRI creating either T1-weighted or T2-weighted images in all three planes without Gadolinium injection. The average age of patients was 9 years. Clinical symptoms were dominated by intracranial hypertension syndrome. Hydatid cyst was solitary and was located in the supratentorial level with an important mass effect on the ventricular system and the median line in most cases. All patients underwent surgery and patients’ evolution was favorable in all cases. CT scan is the test of choice for the diagnosis and the postoperative follow-up of patients with cerebral hydatid cysts. MRI is used essentially in the diagnosis of multiple and atypical type of cerebral hydatid cysts, enabling the design of more effective treatment strategy.

Intracranial hydatid cyst: imaging findings of a rare disease

Hydatid disease (echinococcosis) is a worldwide zoonosis produced by the larval stage of the Echinococcus tapeworm. The disease is endemic in many parts of the world, particularly in the Middle East, Australia, New Zealand, South America and central and south Europe. Intracranial hydatid disease is considered a rare disease and may be sometimes very difficult to diagnose based on the clinical and laboratory findings. Therefore, it is important to be aware of the condition and the imaging findings even in the non-endemic parts of the world. We report the case of a 12-year-old boy who presented with headache and vomiting for a few months. The mass was totally excised, with no postoperative complications. We present MR spectroscopy (MRS) findings in this operatively proven case of hydatid cyst of the brain. We discuss imaging findings, in particular the findings on MRS, which is rarely reported in the literature.

Imaging of parasitic infections of the central nervous system

Parasitic infections of the central nervous system (CNS) have increased over the last couple of decades, partly due to a drop in the living conditions of large populations in the world and the AIDS epidemic. Parasitic infections of the CNS are indolent and often life threatening, hence, an early diagnosis is imperative. While brain biopsy and laboratory analysis remain the gold standard for diagnosis, neuroimaging contributes significantly to diagnosis and follow-up. Imaging can demonstrate the extent of infection and complications and possibly, the type of parasitic infection when characteristic features are evident. The disappearance of the parasite or inflammation, gliosis, and/or calcification suggest a therapeutic response. The initial experience of the CT scan has been greatly enhanced by MRI which is currently the imaging modality of choice. This has been due to the greater tissue contrast resolution of MRI and its ability to detect subtle changes in the tissue parenchyma. Advanced techniques such as diffusion-weighted imaging (DWI), perfusion imaging (PI), MR angiography (MRA), and MR spectroscopy (MRS) have been used to improve the sensitivity for characterizing the type, viability, and burden of the parasites and the host tissue response. Additionally, it is possible to demonstrate the complications of the primary infection and those secondary to treatment, in some cases.

Parasitic diseases of the central nervous system

This article reviews the characteristic imaging appearances of parasitic diseases of the central nervous system, including cysticercosis, toxoplasmosis, cystic echinococcosis, schistosomiasis, amebiasis, malariasis, sparganosis, paragonimiasis, and American and African trypanosomiases. Routine precontrast and postcontrast MR imaging helps in localization, characterization, delineation of extension, and follow-up of the parasitic lesions. Moreover, recently developed tools, such as diffusion, perfusion, and MR spectroscopy, help to differentiate parasitic diseases of the central nervous system from simulating lesions. Combining imaging findings with geographic prevalence, clinical history, and serologic tests is required for diagnosis of parasitic diseases of the central nervous system.

MRS findings in cerebral coenurosis due to Taenia multiceps

Cerebral coenurosis due to Taenia multiceps is a rare infection with no case reports from India. A 55-year-old male patient had presented with progressive symptoms of hemiparesis of 1-year duration. Magnetic resonance imaging (MRI) with magnetic resonance spectroscopy (MRS) of the lesion was performed that showed a septated cystic lesion in left parieto-occipital lobe. Multivoxel MRS through the lesion was performed using repetition time of 1500 ms and time to echo of 144 ms at 3T MRI. MRS showed mildly elevated choline (Cho), depressed creatine (Cr), and N-acetyl aspartate (NAA), a large peak of lactate, pyruvate, and acetate peaks. To best of our knowledge, there has been no reported case of in vivo proton MRS finding ever reported. We present MRS findings in this operatively proven case of T. multiceps cyst of the brain.

[Intracranial hydatid cysts in children: a report of 9 cases]

PURPOSE

To illustrate the value of cross-sectional imaging (CT, MRI) for the diagnosis and follow-up of intracranial hydatid cysts in children.

MATERIALS AND METHODS

Retrospective study of 9 cases of intracranial hydatid cysts in children seen over a period of 8 years. Precontrast and postcontrast 5 mm thick axial CT images were obtained in 7 cases. Noncontrast sagittal, axial and coronal T1W and T2W images were obtained in 2 cases.

RESULTS

Mean patient age was 7.5 years. Intracranial hypertension was the main presenting clinical symptom. A single supratentorial cyst with significant mass effect upon the ventricular system and midline structures was observed in all cases. All patients underwent surgery with good outcome in all cases.

CONCLUSION

CT is the imaging modality of choice for diagnosis and postoperative follow-up of intracranial hydatid cysts in children. MRI is most helpful for further characterization when multiple or atypical cysts are present to optimize management.

Metabolic viability assessment of cystic echinococcosis using high-field 1H MRS of cyst contents

Cystic echinococcosis is a worldwide disease caused by larval stages of the parasite Echinococcus granulosus (canine tapeworm). In clinical practice, staging of cyst development by ultrasonography (US) has allowed treatment options to be tailored to individual patient needs. However, the empirical correlation between cyst morphology and parasite viability is not always dependable and has, until now, required confirmation by invasive assessment of cyst content by light microscopy (LM), for example. Alternatively, high-field 1H MRS may be used to examine cyst fluid ex vivo and prepare detailed quantitative metabolite profiles, enabling a multivariate metabolomics approach to cyst staging. One-dimensional and two-dimensional 1H and 1H/13C MRS at 600 MHz (14.1 T) was used to analyze 50 cyst aspirates of various US and LM classes. MR parameters and concentrations relative to internal valine were determined for 44 metabolites and four substance classes. The high concentrations of succinate, fumarate, malate, acetate, alanine, and lactate found in earlier studies of viable cysts were confirmed, and additional metabolites such as myo-inositol, sorbitol, 1,5-anhydro-D-glucitol, betaine, and 2-hydroxyisovalerate were identified. Data analysis and cyst classification were performed using univariate (succinate), bivariate (succinate vs fumarate), and multivariate partial least squares discriminant analysis (PSL-DA) methods (with up to 48 metabolite variables). Metabolic classification of 23 viable and 18 nonviable cysts on the basis of succinate alone agreed with LM results. However, for seven samples, LM and MRS gave opposing results. Reclassification of these samples and two unclassified samples by PLS-DA prediction techniques led to a set of 50 samples that could be completely separated into viable and nonviable MRS classes with no overlap, using as few as nine variables: succinate, formate, malate, 2-hydroxyisovalerate, acetate, total protein content, 1,5-anhydro-D-glucitol, alanine, and betaine. Thus, future noninvasive in vivo applications of MRS would appear promising.

Sonographic spectrum of hydatid disease

Hydatid disease, caused by Echinococcus granulosus, is a parasitic disease that is endemic in many parts of the world. Hydatid cyst demonstrates a variety of imaging features, varying according to growth stage, associated complications, and affected tissue. The radiologic findings range from purely cystic lesions to a completely solid appearance. Ultrasound is the most important imaging modality for liver hydatid disease and clearly demonstrates the floating membranes, daughter cysts, and hydatid sand characteristically seen in purely cystic lesions. The radiologist's familiarity with the imaging findings of the disease is very important for earlier diagnosis and an appropriate treatment. There are several classification schemes for liver hydatid cysts based on their ultrasound appearances; the initial classification by Gharbi et al and the World Health Organization classification are the most commonly preferred. Computed tomography and magnetic resonance imaging play a key role in recognizing the complications such as rupture and infection of cysts associated with hydatid disease. Today, percutaneous treatment of liver hydatid cysts, a safe, easily applicable, and well-tolerated method, has become the most effective and reliable treatment procedure in most cases if the hydatid cyst is viable. In patients treated with the percutaneous treatment technique, a decrease in the dimensions of the cyst, solidification of the cyst contents, and irregularity in the walls of cysts are signs suggestive of cure. The radiologist should also be familiar with the postoperative follow-up ultrasound findings of hydatid cyst to prevent misinterpretation of the hypoechoic, anechoic, or hyperechoic appearance of posttreatment hydatid disease appearance as recurrence.

Metabolic changes during successful medical therapy for brain hydatid cyst: case report

BACKGROUND

Medical therapy for hydatid disease of the brain has been reported with encouraging results especially in small or medium-sized cysts. To date, no other case correlating the metabolite levels of the cyst with albendazole treatment has been reported.

CASE DESCRIPTION

A 52-year-old woman presented with left hemiparesis and seizure. Cranial magnetic resonance revealed a right frontal cystic mass lesion. A diagnosis of hydatid cyst was made, and she was put on medical therapy with albendazole. An MRS before the medical therapy was begun revealed the typical findings of a hydatid cyst with resonance of alanine, acetate, and succinate that were specific for hydatid disease, and additional nonspecific lactate peaks with an additional small peak of choline. Comparison between the multiple MRS examinations was made by comparing the metabolite ratios specific for hydatid disease to choline, which seemed stable from the beginning. Two sequential MRS imaging revealed a prominent decrease of the succinate and acetate resonance, accompanied by a smaller decline of the alanine resonance progressively, correlated with the conventional MRI findings of the cyst, which had a smaller size with blurred margins in the meantime. After 5 months of medical treatment, the cyst had completely disappeared. The patient has been monitored for 5 years and remains well without recurrence.

CONCLUSIONS

This case provides additional proof that the brain hydatid cyst is a medically treatable disease in appropriate cases. Furthermore, the changes in the metabolic profile of the cyst, especially those regarding succinate and acetate may represent the efficacy of the medical treatment.

Neurocysticercosis as solitary parenchymal lesion confirmed by mitochondrial deoxyribonucleic acid sequence analysis

A 38-year-old Japanese woman presented with neurocysticercosis manifesting as mild hemiparesis. Magnetic resonance (MR) imaging with gadolinium showed a solitary parenchymal lesion. MR spectroscopy of the mass showed a relatively low N-acetylaspartate peak. Enzyme-linked immunosorbent assay of the patient's cerebrospinal fluid using antibodies against several parasite antigens was negative. Surgical resection of the lesion was performed. The histological findings showed the possibility of parasitic infection such as neurocysticercosis, although the definitive type of parasite was not confirmed. Sequencing of cytochrome c oxidase subunit 1 gene of mitochondrial deoxyribonucleic acid indicated the Asian genotype of Taenia solium. We propose that these new diagnostic techniques should be used more widely, especially for solitary lesions of neurocysticercosis.

[Cerebral hydatid disease: imaging features]

Cerebral hytatid cysts (HC) are extremely rare, forming 2% of all intra cranial space occupying lesions even in counties where the disease is endemic. HC diagnosis is usually based on a pathognomonic computed tomography (CT) pattern. In order to assess the value of MR we reviewed the CT (n=25) and magnetic resonance (MR, n=4 including diffusion and proton magnetic resonance spectroscopy in 1) imaging of 25 patients with pathologically confirmed cerebral hydatid disease. 19 HC were seen in children under 16 years. All were supra tentorial with 22 in the middle cerebral artery territory. HC was solitary in 18 cases, unilocular in 23 and multi-vesicular in 2 with heavily calcified pericyst in 1. 2 cysts were intra ventricular and 1 intra aqueducal. The most typical features were well defined, smooth thin walled spherical or oval cystic lesions of CSF density and/or signal with considerable mass effect (20/25). Surrounding oedema with complete or incomplete rim enhancement was seen in 3 cases which were labelled as complicated and/or infected cysts. Although CT is diagnostic of hydatid disease in almost all cases (22/25), MRI including diffusion and spectroscopy precisely demonstrate location, number, cyst capsule, type of signal and enhancement and allows diagnosis of atypical or complicated HC and appears more helpful in surgical planning.

Identification of diffuse and focal brain lesions by clinical magnetic resonance spectroscopy

The purpose of this paper is to facilitate the comparison of magnetic resonance (MR) spectra acquired from unknown brain lesions with published spectra in order to help identify unknown lesions in clinical settings. The paper includes lists of references for published MR spectra of various brain diseases, including pyogenic abscesses, encephalitis (herpes simplex, Rasmussen's and subacute sclerosing panencephalitis), neurocysticercosis, tuberculoma, cysts (arachnoid, epidermoid and hydatid), acute disseminated encephalomyelitis (ADEM), adrenoleukodystrophy (ALD), Alexander disease, Canavan's disease, Krabbe disease (globoid cell leukodystrophy), Leigh's disease, megalencephalic leukoencephalopathy with cysts, metachromatic leukodystrophy (MLD), Pelizaeus-Merzbacher disease, Zellweger syndrome, HIV-associated lesions [cryptococcus, lymphoma, toxoplasmosis and progressive multifocal leukoencephalopathy (PML)], hydrocephalus and tuberous sclerosis. Each list includes information on the echo time(s) (TE) of the published spectra, whether a control spectrum is shown, whether the corresponding image and voxel position are shown and the patient ages if known. The references are listed in the approximate order of usefulness, based on spectral quality, number of spectra, range of echo times and whether the voxel positions are shown. Spectra of Zellweger syndrome, cryptococcal infection, toxoplasmosis and lymphoma are included, along with a spectrum showing propanediol (propylene glycol).

Cysticercosis: Recent Advances in Diagnosis and Management of Neurocysticercosis

Neurocysticercosis, caused by infection with the pork tapeworm Taenia solium, is increasingly recognized as a cause of neurologic disease worldwide. Because the clinical presentation is nonspecific, diagnosis has been difficult. Advances in imaging studies and serodiagnostic techniques are facilitating the diagnosis of neurocysticercosis and tapeworm carriers. Neurocysticercosis represents a spectrum of disease. Seizures are the main clinical manifestation in parenchymal neurocysticercosis. Recent studies emphasize that such seizures are the result of the host inflammatory response, even in patients who only have calcifications with no viable cysticerci. Controlled clinical trials have demonstrated that antiparasitic drugs can decrease the number of generalized seizures, although the benefit is small and confined to a subgroup of patients. Corticosteroids can also decrease seizure frequency. Case studies have demonstrated that endoscopic surgery appears to be the optimal approach to ventricular cysts. Recombinant vaccines are being developed and may prove important in disease control.