C. Colosimo

The role of brain infarcts and hippocampal atrophy in subcortical ischaemic vascular dementia

Abstract.We investigated if, in patients with vascular lesions, the variable that best discriminated demented from non–demented patients was the severity of the vascular pathology or the degree of hippocampal atrophy. A total of 39 patients multiple subcortical infarcts, who could be considered as possible vascular dementia with small vessel pathology, with underwent a neuropsychological study and brain magnetic resonance imaging (MRI) DSM IV criteria supported by neuropsychological data were used to distinguish demented from non–demented patients. The MRI study took into account the degree of hippocampal atrophy (hippocampal height and interuncal distance) and the severity of vascular pathology (number of brain infarcts). The distribution of lesions and a factor analysis showed that hippocampal atrophy is a better predictor of dementia than the number of brain infarcts. Multiple subcortical infarcts alone are probably not able to cause clinical dementia but the presence of vascular lesions increases the expression of concomitant Alzheimer’s disease.

Neuroradiology of Brain Stem and Cervicomedullary tumours

Brain stem and cervicomedullary tumours are typical of paediatric age, 80% of them occurring in patients under 18 years of age, and comprising 10–15% of all childhood and adolescent brain tumours, as well as 20–25% of infratentorial locations. They are characteristically pontine tumours (60% of the cases), but they commonly extend to involve the medulla, midbrain and cerebellum. Although most brain stem tumours are low grade gliomas, their prognosis is extremely severe (no more than 20% of patients are alive 3 years after diagnosis and the 5-year survival rate is 5%) because both the typical infiltrating nature and the neuro-anatomical location usually make them surgically unresectable. Surgery is generally limited to biopsy, partial decompression, or excission of the exophytic components, because of the extremely severe functional sequelae of even minor resections. Thus, the mainstay of therapy has been based on irradiation alone or combined with chemotherapy, doses of 5000–5500 cGy being usually adequate for tumour shrinkage or remission, even if recurrence is common after 10–15 months. At present, it is very important to establish reliable, homogeneous, objective, and reproducible diagnostic criteria for the identification of patient subsets with predictable histology, prognosis and possible therapeutic management, in some cases histology, site and relationship of tumour enabling total or subtotal resection with a lower operative risk. Since its introduction, magnetic resonance imaging (MRI) has appeared the procedure of choice for the neuroradiologic study of the brain stem and brain stem tumours, enabling a more precise definition of their margins, a correct assessment of intrinsic and exophytic components, as well as a satisfactory characterization of pathologic tissue. MRI studies should include good quality T1-, PD- and T2-weighted images and T1-weighted images after gadolinium i.v., T2-weighted sagittal images being required for complete evaluation of tumour extent. Computed tomography is still superior in the identification of calcifications and acute intratumoral haemorrhage; it is rapidly performed, thus representing the first choice procedure in emergency, i.e. the diagnosis of hydrocephalus. Epstein has proposed the most widely accepted classification system of brain stem tumours, essentially based on neuroradiological findings, surgical and stereotactic biopsy and histology generally resulting in understaging. This classification system separates intrinsic (diffuse, focal, cervico-medullary), exophytic (anterolateral into cerebellopontine angle, posterolateral into brachium pontis, posterior into fourth ventricle) and cerebrospinal fluid seeding (positive cytology or myelography) tumors. More recently, Barkovich – based on a multicentric study of some of the most important paediatric neurosurgery and neuro-oncology centres of the United States – has clearly defined the neuroradiological parameters which must be considered for an objective and reproducible assessment of brain stem gliomas, in order to identify patient subsets characterized by predictable histology, prognosis and possible therapeutic management. We agree with him, emphasizing that the evaluation of brain stem tumours must include a careful interpretation of all MRI findings (tumour site and origin; dimensions/degree of brain stem enlargement; tumour caudo-cranial and transverse extension; exophytic components; tumour characteristics as defined by MRI signal intensity; cysts, haemorrhage, necrosis, calcifications; ventricular dimensions and hydrocephalus; leptomeninengeal seeding) that can help in the definition of the following tumour subsets: diffuse pontine tumours, medullary tumours, cervicomedullary tumours, focal brain stem tumours. With regard to the neuroradiological follow-up, in patients undergoing surgery (for biopsy decompression or less frequently for radicality), the role of the neuroradiologist is similar to that in other fields of neurosurgery, and concerns the quantitation of the extent of the resection and the identification of possible parenchymal injuries or postoperative haemorrhage, always keeping in mind the negative effects of postoperative reactive phenomena and the blood-brain disruption 24–48 hours to 30–40 days after surgery. However, the major contribution of the neuroradiologist is the objective evaluation of irradiation effects and recently of combined irradiation and chemotherapy. In our experience, the efficacy of irradiation is well evaluated by MRI only 3 or 6 months after the end of treatment, even if a clinical improvement is possible after 30–60 days. However, tumour shrinkage is rarely drastic, and its disappearance, as well as that of signal alterations, is exceptional. Qualitative modifications occurring within the tumour are more difficult to interpret, because of the appearance of cystic or pseudocystic areas, markedly increased enhancement, and small areas of haemorrhage may be related both to irradiation-induced regressive modifications and disease progression. In conclusion, MRI represents the gold standard in the evaluation of brain stem and cervicomedullary tumors, always enabling a precise definition of tumour site and extent, and in most cases the diagnosis of nature, thus allowing the identification of patients who can undergo radical microsurgery. MRI follow-up controls the extent of resection and the effect of combined irradiation and chemotherapy; disease progression is evidenced and spinal seeding can be diagnosed. However, the differentiation between tumour recurrence and irradiation-induced injury may be difficult if only based on morphological data. These limitations of MRI will probably be reduced by the advances in ultra-fast MRI technology and 18F-fluoro-deoxy-glucose positron emission tomography which supplies in vivo metabolic and functional information.

CT and MRI diagnosis of silent sinus syndrome@@@Diagnosi TC ed RM della sindrome del seno silenzioso

Purpose. The purpose of this study was to determine computed tomography (CT) and magnetic resonance (MR) findings of silent sinus syndrome (SSS) – a rare clinical entity with the constellation of progressive enophthalmos and hypoglobus, facial asymmetry and possible diplopia – due to otherwise asymptomatic maxillary sinus disease. Materials and methods. We reviewed the preand postoperative CT and MR images of six patients with a definitive diagnosis of SSS and compared the radiological and clinical findings with those reported in the literature. Results. The CT and MR studies demonstrated in all cases the most characteristic imaging features of SSS reported in the literature. Conclusions. Both CT and MR imaging enable a diagnosis of SSS to be made, but CT provides a better depiction of all features of SSS necessary for diagnosis and differentiation from other sinus conditions, even in patients without a clinical suspicion of SSS.PurposeThe purpose of this study was to determine computed tomography (CT) and magnetic resonance (MR) findings of silent sinus syndrome (SSS) — a rare clinical entity with the constellation of progressive enophthalmos and hypoglobus, facial asymmetry and possible diplopia — due to otherwise asymptomatic maxillary sinus disease.Materials and methodsWe reviewed the pre- and postoperative CT and MR images of six patients with a definitive diagnosis of SSS and compared the radiological and clinical findings with those reported in the literature.ResultsThe CT and MR studies demonstrated in all cases the most characteristic imaging features of SSS reported in the literature.ConclusionsBoth CT and MR imaging enable a diagnosis of SSS to be made, but CT provides a better depiction of all features of SSS necessary for diagnosis and differentiation from other sinus conditions, even in patients without a clinical suspicion of SSS.RiassuntoObiettivoLo scopo di questo lavoro è la presentazione dei reperti caratteristici di tomografia computerizzata (TC) e risonanza magnetica (RM) su cui si basa la diagnosi della sindrome del seno silenzioso (SSS), una rara condizione clinica caratterizzata da enoftalmo ed ipoglobo monolaterali, asimmetria facciale e possibile diplopia, nel contesto di una sinusopatia pauci-/asintomatica.Materiali e metodiAbbiamo valutato gli studi RM e TC, pre- e post-chirurgia, di sei pazienti con diagnosi definitiva di SSS. I reperti radiologici e clinici della nostra casistica sono stati confrontati con i dati della letteratura.RisultatiI reperti caratteristici della SSS riportati in letteratura sono stati rilevati in tutti gi studi TC ed RM della nostra casistica.ConclusioniEntrambe le metodiche (TC e RM) consentono la diagnosi di SSS, ma la TC dimostra più facilmente gli elementi essenziali per la diagnosi e la diagnosi differenziale rispetto alle altre patologie sinusali, anche in pazienti senza un corretto inquadramento clinico.

Magnetic resonance imaging of solitary brain metastases: main findings of nonmorphological sequences La risonanza magnetica delle metastasi cerebrali solitarie: definizione dei reperti più significativi delle tecniche non morfologiche

PurposeThis study was done to investigate the usefulness of diffusion-weighted (DWI), perfusion-weighted (PWI) and proton magnetic resonance (MR) spectroscopy imaging in characterising solitary brain metastases.Materials and methodsFifty-nine solitary brain metastases were evaluated with conventional and nonmorphological MR imaging: DWI, PWI and MR spectroscopy. We evaluated size, signal intensity and contrast enhancement and calculated apparent diffusion coefficient (ADC), relative cerebral blood volume (rCBV), percentage of signal intensity recovery (PSR) and maximum values of N-acetylaspartate (NAA), choline (Cho), creatine (Cr), lipids (Lip), NAA/Cr and Cho/Cr. The nonmorphological parameters were compared with those from the literature for brain lesions that frequently enter the differential diagnosis with metastases.ResultsSignal intensity and contrast enhancement patterns were variable. There was a wide range of ADC values: min:max 0.59×10−3:1.88×10−3. Compared with normal white matter, rCBV was higher in lesions (3.30±1.59) and lower in perilesional oedema (0.42±0.15). Mean and minimum PSR were 57% and 48%, respectively; lip and Cho were elevated and NAA reduced.ConclusionsConventional MR findings of solitary metastases are heterogeneous, and some values of nonmorphological sequences are similar to those of other brain lesions. PWI seems to be the nonmorphological MR technique that may best contribute to the diagnosis of brain metastases.RiassuntoObiettivoScopo del presente lavoro è stato valutare l’utilità dell’imaging di diffusione (DWI), perfusione (PWI) e spettroscopia (MRS) nella caratterizzazione delle metastasi cerebrali solitarie.Materiali e metodiAbbiamo studiato 59 metastasi cerebrali uniche con sequenze di risonanza magnetica (RM) morfologiche e non morfologiche: DWI, PWI e MRS. Abbiamo valutato dimensioni, caratteristiche di segnale e contrast enhancement (CE), calcolato coefficiente di diffusione apparente (ADC), volume cerebrale ematico relativo (rCBV), percentuale di recupero della curva (RC), valori massimi di N-acetil-aspartato (NAA), colina (Cho), creatina (Cr), lipidi (lip), NAA/Cr, Cho/Cr. I parametri non morfologici sono stati confrontati con quelli della letteratura per le lesioni che frequentemente entrano in diagnosi differenziale con le metastasi.RisultatiCaratteristiche di segnale e pattern di CE sono risultati variabili. Ampio il range di valori di ADC: minmax 0,59×10−3-1,88×10−3. Rispetto alla sostanza bianca normale il rCBV nelle lesioni era superiore (3,30±1,59) e nell’edema perilesionale inferiore (0,42±0,15). La percentuale media e minima di RC erano 57% e 48%. Sono risultati aumentati lip e Cho, ridotto l’NAA.ConclusioniGli aspetti RM morfologici delle metastasi solitarie risultano variabili ed alcuni valori delle metodiche non morfologiche sovrapponibili a quelli di altre lesioni encefaliche. La perfusione sembra la metodica non morfologica RM in grado di contribuire più significativamente alla diagnosi di metastasi encefalica.

The Neuroradiological Approach to Patients in Coma

Coma is rightly considered to be the one of the most commonly occurring neurological emergency conditions. Coma can be the consequence of an entire spectrum of pathological conditions and thus requires equally varied but quite specific treatment (8, 15, 16). Neuroradiological studies are often the only real practical option for initial diagnostic patient investigation, as the clinician may have access to little or no information when the patient is admitted. In such situations, it is almost always Computed Tomography (CT) that assumes the leading role in the initial diagnostic, prognostic and therapeutic approach. The fundamental question is whether or not there are documentable intracranial neuroanatomical alterations, which, if present, can be subsequently monitored after the patient is admitted to the intensive care suite. We will not deal in detail here with the entire spectrum of the intracranial pathology responsible for causing coma, as they are dealt with separately in the various chapters of this volume; instead, we will briefly outline the optimal neuroradiological approach to be utilized in patients in coma including: a) the modes of investigation; b) the related technical variables; c) conditions causing acute focal lesions (9), and d) conditions causing diffuse brain impairment.

Dural Sinuses Thrombosis: Gadolinium-Enhanced Magnetic Resonance Angiography Findings at the Exordium and during Follow-up

859 med with gadolinium injection is currently routinely employed in supra-aortic vessels evaluation. In our knowledge, there is no previous experience in the Literature involving the use of this technique in dural sinuses disease. Our aim is to underline the powerful diagnostic tools of MRA for the early diagnosis, timely accurate medical treatment and the best follow-up management; to evaluate the usefulness of gadolinium-enhanced ultra-fast (GEUF) MRA in the diagnosis and follow-up of dural sinuses thrombosis and to describe the relationship between the involved dural sinus and location of secondary brain lesions.