M. Armillotta

Role of perfusion-weighted imaging at 3 Tesla in the assessment of malignancy of cerebral gliomas

PurposeThis study was performed to clarify the role of perfusion-weighted imaging (PWI) at 3 Tesla in the characterisation of haemodynamic heterogeneity within gliomas and surrounding tissues and in the differentiation of high-grade from low-grade gliomas.Materials and methodsWe examined 36 patients with histologically verified gliomas (25 with high-grade and 11 with low-grade gliomas). PWI was performed by first-pass gadopentetate dimeglumine T2*-weighted echo-planar images, and cerebral blood volume (CBV) maps were computed with a nondiffusible tracer model. Relative CBV (rCBV) was calculated by dividing CBV in pathological areas by that in contralateral white matter.ResultsIn high-grade gliomas, rCBV were markedly increased in mass [mean±standard deviation (SD), 4.3±1.2] and margins (4.0±1.1) and reduced in necrotic areas (0.3±0.3). Oedematous-appearing areas were divided in two groups according to signal intensity on T2-weighted images: tumour with lower (nearly isointense to grey matter) and oedema with higher (scarcely isointense to cerebrospinal fluid) signal intensity. Tumour showed significantly higher rCBV than did oedema (1.8±0.5 vs. 0.5±0.2; p<0.001) areas. In low-grade gliomas, mass (2.0±1.5) and margin (2.2±1.2) rCBV were significantly lower than in high-grade gliomas (p<0.001).ConclusionsThree-Tesla PWI helps to distinguish necrosis from tumour mass, infiltrating tumour from oedema and high-grade from low-grade gliomas. It enhances the magnetic resonance (MR) assessment of cerebral gliomas and provides useful information for planning surgical and radiation treatment.RiassuntoObiettivoChiarire il ruolo dell’imaging pesato in perfusione (PWI) a 3 Tesla nella caratterizzazione dell’eterogeneità emodinamica dei gliomi cerebrali e dei tessuti circostanti, e nella differenziazione dei gliomi di alto grado da quelli di basso grado.Materiali e metodiAbbiamo esaminato 36 pazienti con gliomi verificati istologicamente (25 con alto ed 11 con basso grado). Il PWI è stato ottenuto mediante immagini eco-planari T2*-pesate con primo passaggio di gadopentetato di dimeglumina, e le mappe di volume ematico cerebrale (CBV) sono state elaborate con il modello del tracciante non diffusibile. Il volume ematico cerebrale relativo (rCBV) è stato calcolato dividendo il CBV nelle aree patologiche per quello nella sostanza bianca controlaterale.RisultatiNei gliomi di alto grado, l’rCBV appariva marcatamente incrementato nella massa (media±SD, 4,3±1,2) ed ai margini (4,0±1,1), e ridotto nelle aree necrotiche (0,3±0,3). Le regioni apparentemente edematose sono state divise in due gruppi sulla base dell’intensità di segnale nelle immagini pesate in T2: “tumore” con più basso segnale (quasi isointenso alla sostanza grigia) ed “edema” con segnale più elevato (quasi isointenso al liquido cefalorachidiano). Le aree “tumore” presentavano rCBV significativamente più elevato rispetto a quelle “edema” (1,8±0,5 vs 0,5±0,2; p<0,001). Nei gliomi di basso grado, l’rCBV nella massa (2,0±1,5) e nel margine (2,2±1,2) erano significativamente più bassi che nei gliomi di alto grado (p<0,001).ConclusioniIl PWI a 3T aiuta a differenziare la necrosi dalla massa tumorale, il tumore infiltrante dall’edema, e i gliomi di alto grado da quelli di basso grado. Esso facilita la caratterizzazione in RM dei gliomi cerebrali e fornisce utili informazioni per la pianificazione del trattamento chirurgico e radiante.

Rotator cable at MR imaging: considerations on morphological aspects and biomechanical role.

PurposeThe rotator cable (RC) is a thickening of the coracohumeral ligament. It extends from the coracohumeral ligament to the inferior border of the infraspinatus tendon, with fibres running perpendicularly to the rotator cuff fibres. According to some authors, the RC tends to thicken with age, thus allowing some individuals with a cuff lesion to preserve normal shoulder function. We evaluated the RC with magnetic resonance (MR) imaging and investigated its possible role in the biomechanics of the shoulder affected by cuff lesions.Materials and methodsBetween November 2007 and May 2008, we performed shoulder MR examinations for shoulder pain or disability on 94 patients (46 males, 48 females; age range 16–79 years; mean age 54.09±15.09 years) for a total of 104 shoulders (62 right, 42 left).ResultsRC was more easily detectable in oblique coronal scans where it appeared as a crescent-shaped, regularly marginated structure adjacent to the articular surface of the supraspinatus tendon and medial to the insertion point of this tendon on the greater tuberosity. Its thickness was 2.8±0.3 mm. The structure was identified in 62% of cases (mean patient age 55.3±14.9 years). No statistically significant difference in age was found between patients with and without evidence of RC (Student’s t test=0.05; p=0.82). Among patients with partial- or full-thickness supraspinatus tendon lesions at MR imaging, no statistically significant difference was found between the presence or absence of RC and disability on Jobe’s test (χ2=1.17; p>0.05).ConclusionsRC can be observed at MR imaging in >60% cases. In our sample it did not seem to influence shoulder function in patients with cuff lesions.RiassuntoObiettivoIl rotator cable (RC) è un ispessimento del legamento coraco-omerale. Esso si estende dal legamento coraco-omerale fino al margine inferiore del tendine dell’infraspinato con fibre che decorrono perpendicolarmente a quelle dei tendini della cuffia dei rotatori. Secondo alcuni autori, il RC tenderebbe ad ispessirsi con l’età consentendo ad alcuni pazienti con lesioni di cuffia di conservare la normale funzionalità della spalla. Scopo del nostro lavoro è stato valutare il RC attraverso la risonanza magnetica (RM) e definire il suo possibile ruolo nella biomeccanica della spalla in soggetti con lesione di cuffia.Materiali e metodiDa novembre 2007 a maggio 2008 abbiamo reclutato 94 pazienti (46 maschi e 48 femmine), per un totale di 104 spalle (62 destre e 42 sinistre), di età compresa tra i 16 ed i 79 anni (età media 54,09±15,09 anni), che effettuavano l’esame di RM della spalla per dolore o limitazione funzionale.RisultatiIl RC è più agevolmente individuabile nelle scansioni coronali-oblique ove appare come una struttura a forma di semiluna, con margini regolari, adiacente alla superficie articolare del tendine sopraspinato, medialmente al punto d’inserzione di questo tendine sulla grande tuberosità. Il suo spessore è 2,8±0,3 mm. La struttura è stata identificata nel 62% dei casi (età media dei pazienti 55,3±14,9 anni). Non è stata riscontrata alcuna differenza statisticamente significativa per quanto riguardava l’età tra pazienti con o senza evidenza di RC (test t di Student=0,05; p=0,82). Nel gruppo di pazienti che presentavano lesioni parziali o complete del tendine sovraspinoso non è stata osservata alcuna differenza statisticamente significativa tra presenza o assenza del RC e limitazione funzionale al test di Jobe (χ2=1,17; p>0,05).ConclusioniIl RC può essere osservato in RM in più del 60% dei casi. Nel nostro campione di studio esso non sembra influenzare la funzionalità della spalla in pazienti con lesioni di cuffia.

3.0-T morphological and angiographic brain imaging: a 5-years experience

Ever since the introduction of magnetic resonance (MR), imaging with 1.5 Tesla (T) has been considered the gold standard for the study of all areas of the body. Until not long ago, higher-field MR equipment was exclusively employed for research, not for clinical use. More recently, the introduction of 3.0-T MR machines for new and more sophisticated clinical applications has resulted in important benefits, especially in neuroradiology. Indeed, their high gradient power and field intensity (3.0 T) allow adjunctive and more advanced diagnostic methodologies to be performed with excellent resolution in a fraction of the acquisition time required with earlier machines. The purpose of this paper is to illustrate the distinctive semeiological characteristics of 3.0-T morphological and angiographic brain imaging compared with lower-field systems and highlight the respective advantages and drawbacks based on the experience gained in the first 5 years from the installation of a 3.0-T magnet.

Ruolo dell'imaging pesato in perfusione a 3 Tesla nella valutazione del grado di malignità dei gliomi cerebrali

PurposeThis study was performed to clarify the role of perfusion-weighted imaging (PWI) at 3 Tesla in the characterisation of haemodynamic heterogeneity within gliomas and surrounding tissues and in the differentiation of high-grade from low-grade gliomas.Materials and methodsWe examined 36 patients with histologically verified gliomas (25 with high-grade and 11 with low-grade gliomas). PWI was performed by first-pass gadopentetate dimeglumine T2*-weighted echo-planar images, and cerebral blood volume (CBV) maps were computed with a nondiffusible tracer model. Relative CBV (rCBV) was calculated by dividing CBV in pathological areas by that in contralateral white matter.ResultsIn high-grade gliomas, rCBV were markedly increased in mass [mean±standard deviation (SD), 4.3±1.2] and margins (4.0±1.1) and reduced in necrotic areas (0.3±0.3). Oedematous-appearing areas were divided in two groups according to signal intensity on T2-weighted images: tumour with lower (nearly isointense to grey matter) and oedema with higher (scarcely isointense to cerebrospinal fluid) signal intensity. Tumour showed significantly higher rCBV than did oedema (1.8±0.5 vs. 0.5±0.2; p<0.001) areas. In low-grade gliomas, mass (2.0±1.5) and margin (2.2±1.2) rCBV were significantly lower than in high-grade gliomas (p<0.001).ConclusionsThree-Tesla PWI helps to distinguish necrosis from tumour mass, infiltrating tumour from oedema and high-grade from low-grade gliomas. It enhances the magnetic resonance (MR) assessment of cerebral gliomas and provides useful information for planning surgical and radiation treatment.RiassuntoObiettivoChiarire il ruolo dell’imaging pesato in perfusione (PWI) a 3 Tesla nella caratterizzazione dell’eterogeneità emodinamica dei gliomi cerebrali e dei tessuti circostanti, e nella differenziazione dei gliomi di alto grado da quelli di basso grado.Materiali e metodiAbbiamo esaminato 36 pazienti con gliomi verificati istologicamente (25 con alto ed 11 con basso grado). Il PWI è stato ottenuto mediante immagini eco-planari T2*-pesate con primo passaggio di gadopentetato di dimeglumina, e le mappe di volume ematico cerebrale (CBV) sono state elaborate con il modello del tracciante non diffusibile. Il volume ematico cerebrale relativo (rCBV) è stato calcolato dividendo il CBV nelle aree patologiche per quello nella sostanza bianca controlaterale.RisultatiNei gliomi di alto grado, l’rCBV appariva marcatamente incrementato nella massa (media±SD, 4,3±1,2) ed ai margini (4,0±1,1), e ridotto nelle aree necrotiche (0,3±0,3). Le regioni apparentemente edematose sono state divise in due gruppi sulla base dell’intensità di segnale nelle immagini pesate in T2: “tumore” con più basso segnale (quasi isointenso alla sostanza grigia) ed “edema” con segnale più elevato (quasi isointenso al liquido cefalorachidiano). Le aree “tumore” presentavano rCBV significativamente più elevato rispetto a quelle “edema” (1,8±0,5 vs 0,5±0,2; p<0,001). Nei gliomi di basso grado, l’rCBV nella massa (2,0±1,5) e nel margine (2,2±1,2) erano significativamente più bassi che nei gliomi di alto grado (p<0,001).ConclusioniIl PWI a 3T aiuta a differenziare la necrosi dalla massa tumorale, il tumore infiltrante dall’edema, e i gliomi di alto grado da quelli di basso grado. Esso facilita la caratterizzazione in RM dei gliomi cerebrali e fornisce utili informazioni per la pianificazione del trattamento chirurgico e radiante.

Role of perfusion-weighted imaging at 3 Tesla in the assessment of malignancy of cerebral gliomas@@@Ruolo dell’imaging pesato in perfusione a 3 Tesla nella valutazione del grado di malignità dei gliomi cerebrali

PurposeThis study was performed to clarify the role of perfusion-weighted imaging (PWI) at 3 Tesla in the characterisation of haemodynamic heterogeneity within gliomas and surrounding tissues and in the differentiation of high-grade from low-grade gliomas.Materials and methodsWe examined 36 patients with histologically verified gliomas (25 with high-grade and 11 with low-grade gliomas). PWI was performed by first-pass gadopentetate dimeglumine T2*-weighted echo-planar images, and cerebral blood volume (CBV) maps were computed with a nondiffusible tracer model. Relative CBV (rCBV) was calculated by dividing CBV in pathological areas by that in contralateral white matter.ResultsIn high-grade gliomas, rCBV were markedly increased in mass [mean±standard deviation (SD), 4.3±1.2] and margins (4.0±1.1) and reduced in necrotic areas (0.3±0.3). Oedematous-appearing areas were divided in two groups according to signal intensity on T2-weighted images: tumour with lower (nearly isointense to grey matter) and oedema with higher (scarcely isointense to cerebrospinal fluid) signal intensity. Tumour showed significantly higher rCBV than did oedema (1.8±0.5 vs. 0.5±0.2; p<0.001) areas. In low-grade gliomas, mass (2.0±1.5) and margin (2.2±1.2) rCBV were significantly lower than in high-grade gliomas (p<0.001).ConclusionsThree-Tesla PWI helps to distinguish necrosis from tumour mass, infiltrating tumour from oedema and high-grade from low-grade gliomas. It enhances the magnetic resonance (MR) assessment of cerebral gliomas and provides useful information for planning surgical and radiation treatment.RiassuntoObiettivoChiarire il ruolo dell’imaging pesato in perfusione (PWI) a 3 Tesla nella caratterizzazione dell’eterogeneità emodinamica dei gliomi cerebrali e dei tessuti circostanti, e nella differenziazione dei gliomi di alto grado da quelli di basso grado.Materiali e metodiAbbiamo esaminato 36 pazienti con gliomi verificati istologicamente (25 con alto ed 11 con basso grado). Il PWI è stato ottenuto mediante immagini eco-planari T2*-pesate con primo passaggio di gadopentetato di dimeglumina, e le mappe di volume ematico cerebrale (CBV) sono state elaborate con il modello del tracciante non diffusibile. Il volume ematico cerebrale relativo (rCBV) è stato calcolato dividendo il CBV nelle aree patologiche per quello nella sostanza bianca controlaterale.RisultatiNei gliomi di alto grado, l’rCBV appariva marcatamente incrementato nella massa (media±SD, 4,3±1,2) ed ai margini (4,0±1,1), e ridotto nelle aree necrotiche (0,3±0,3). Le regioni apparentemente edematose sono state divise in due gruppi sulla base dell’intensità di segnale nelle immagini pesate in T2: “tumore” con più basso segnale (quasi isointenso alla sostanza grigia) ed “edema” con segnale più elevato (quasi isointenso al liquido cefalorachidiano). Le aree “tumore” presentavano rCBV significativamente più elevato rispetto a quelle “edema” (1,8±0,5 vs 0,5±0,2; p<0,001). Nei gliomi di basso grado, l’rCBV nella massa (2,0±1,5) e nel margine (2,2±1,2) erano significativamente più bassi che nei gliomi di alto grado (p<0,001).ConclusioniIl PWI a 3T aiuta a differenziare la necrosi dalla massa tumorale, il tumore infiltrante dall’edema, e i gliomi di alto grado da quelli di basso grado. Esso facilita la caratterizzazione in RM dei gliomi cerebrali e fornisce utili informazioni per la pianificazione del trattamento chirurgico e radiante.

L'imaging morfologico ed angiografico cerebrale 3,0 T: L'esperienza di 5 anni

Ever since the introduction of magnetic resonance (MR), imaging with 1.5 Tesla (T) has been considered the gold standard for the study of all areas of the body. Until not long ago, higher-field MR equipment was exclusively employed for research, not for clinical use. More recently, the introduction of 3.0-T MR machines for new and more sophisticated clinical applications has resulted in important benefits, especially in neuroradiology. Indeed, their high gradient power and field intensity (3.0 T) allow adjunctive and more advanced diagnostic methodologies to be performed with excellent resolution in a fraction of the acquisition time required with earlier machines. The purpose of this paper is to illustrate the distinctive semeiological characteristics of 3.0-T morphological and angiographic brain imaging compared with lower-field systems and highlight the respective advantages and drawbacks based on the experience gained in the first 5 years from the installation of a 3.0-T magnet.

3.0-T morphological and angiographic brain imaging: a 5-years experience L'imaging morfologico ed angiografico cerebrale 3,0 T: l'esperienza di 5 anni

Ever since the introduction of magnetic resonance (MR), imaging with 1.5 Tesla (T) has been considered the gold standard for the study of all areas of the body. Until not long ago, higher-field MR equipment was exclusively employed for research, not for clinical use. More recently, the introduction of 3.0-T MR machines for new and more sophisticated clinical applications has resulted in important benefits, especially in neuroradiology. Indeed, their high gradient power and field intensity (3.0 T) allow adjunctive and more advanced diagnostic methodologies to be performed with excellent resolution in a fraction of the acquisition time required with earlier machines. The purpose of this paper is to illustrate the distinctive semeiological characteristics of 3.0-T morphological and angiographic brain imaging compared with lower-field systems and highlight the respective advantages and drawbacks based on the experience gained in the first 5 years from the installation of a 3.0-T magnet.

3.0 T Perfusion Studies

Perfusion MRI is a valuable and flexible clinical tool enabling the assessment of regional cerebral haemodynamics using a variety of techniques and playing a relevant role in treatment strategies (e.g. in deciding which patient should undergo thrombolysis).

3.0 T Imaging of Ischaemic Stroke

Ischaemic stroke accounts for 70 % of all acute cerebral vasculopathies and is among the leading causes of death and disability in the Western world. It is most often due to brain vessel atherosclerosis and less commonly to infectious arteritis, emboli from the carotid artery or cardiac pump deficits, resulting in systemic hypoperfusion. A significantly reduced blood flow in the vascular territory supplying the affected vessels induces a metabolic tissue imbalance (hypoxia and hypoglycaemia) that gives rise to variably reversible anatomical injury. Four grades of clinical severity can be distinguished on the basis of the duration of symptoms, which are mainly characterized by a focal neurological deficit: 1. TIA (transient ischaemic attack): a sudden-onset, focal, non-convulsive condition that usually resolves within a few minutes and always within 24 h. 2. RIND (reversible ischaemic neurological deficit): symptoms last no more than 48 h and normal conditions are restored within 3 weeks. 3. Progressive stroke: progressive onset of clinical symptoms worsening over the first 24–48 h and leaving a persistent functional deficit. 4. Completed stroke: a stable clinical condition since onset that may improve in time.

High-Field MRI and Safety: I. Installation

High-field magnetic resonance (MR), originally developed in the framework of spectroscopy and functional neuroradiology, is set to become an important diagnostic tool not only in research but also in advanced clinical practice. High magnetic fields afford a better signal/noise ratio (SNR) and consequently better spatial resolution in a shorter acquisition time, even though the diagnostic outcome is then subject to the dependence on the magnetic field of other factors that variously contribute to image quality. The rationale for the utilization of high magnetic fields in MR diagnostic imaging is obvious. The distribution of the population into two spin levels is statistically determined: