This study was undertaken to evaluate the usefulness of perfusion-weighted imaging (PWI) in the differential diagnosis of ring-enhancing cerebral lesions, including abscesses, high-grade gliomas and metastases.Nine cerebral abscesses (five pyogenic, four from Toxoplasma gondii), ten glioblastomas and five cerebral metastases in 19 patients were studied with gadolinium-enhanced magnetic resonance imaging, diffusion-weighted imaging (DWI) including calculation of mean apparent diffusion coefficient (ADC) of the lesion core, and PWI. At PWI, the mean of the maximum regional cerebral blood volume (rCBV) was calculated in the gadolinium-enhancing peripheral solid areas and compared with that of the contralateral normal-appearing white matter [ratio=rCBV (lesion)/rCBV (contralateral normal-appearing white matter)].DWI achieved the differential diagnosis in all cases except for the four Toxoplasma abscesses. At PWI, the mean ratio of the rCBV of the capsular portion was 0.72±0.08 (range 0.60–0.82) in the pyogenic abscesses, 0.84±0.07 (range 0.75–0.91) in the Toxoplasma abscesses, 4.45±1.5 (range 2.9–8.0) in the high-grade gliomas and 3.58±0.68 (range 3.28–4.27) in the metastases.PWI seems to be useful in the differential diagnosis of ring-enhancing cerebral lesions. High rCBV values in the peripheral areas appear to indicate the possibility of a necrotic tumour, whereas low values tend to indicate an abscess.Valutare l’utilità della perfusione-RM nella diagnosi differenziale delle lesioni cerebrali con “ringenhancement”, quali ascessi, gliomi di alto grado e metastasi.Nove ascessi cerebrali (5 da piogeni, 4 da Toxoplasma gondii), 10 glioblastomi e 5 metastasi cerebrali in 19 pazienti sono stati studiati con risonanza magnetica con gadolinio endovena, diffusione-RM con calcolo del valore medio del coefficiente di diffusione apparente (DWI-ADC) del centro della lesione e perfusione-RM. Alla perfusione-RM, il valore medio del massimo volume ematico cerebrale regionale (rCBV) è stato calcolato nelle aree solide periferiche e confrontato con quelli della sostanza bianca controlaterale di aspetto normale [ratio=rCBV(lesione)/rCBV(sostanza bianca controlaterale)].La DWI-ADC ha consentito la diagnosi differenziale in tutti i casi, ad eccezione dei 4 ascessi da Toxoplasma gondii. Alla perfusione-RM, la ratio media del rCBV della porzione capsulare è stata di 0,72±0,08 (range: 0,6–0,82) negli ascessi da piogeni, 0,84±0,07 (range: 0,75–0,91) negli ascessi da Toxoplasma gondii, 4,45±1,5 (range: 2,9–8) nei gliomi di alto grado e 3,58±0,68 (range: 3,28–4,27) nelle metastasi.La perfusione-RM fornisce utili elementi alla diagnosi differenziale delle lesioni cerebrali con “ringenhancement”. Alti valori del rCBV nelle aree periferiche dovrebbero indurre al sospetto di tumore necrotico, mentre bassi valori del rCBV possono orientare verso l’ascesso.

Radiologia medica

Diffusion-weighted imaging; Perfusione-RM; Diagnostic Radiology; Diffusione-RM; Neuroradiology; Perfusion-weighted imaging Ring-enhancement; Cerebral tumours; Ring-enhancement; Tumori cerebrali; Medicine & Public Health; Interventional Radiology; Cerebral abscess; Ascesso cerebrale; Imaging / Radiology; Ultrasound; Diagnosis, Differential; Toxoplasmosis, Cerebral - diagnosis; Glioblastoma - diagnosis; Brain Abscess - diagnosis; Brain Neoplasms - diagnosis; Humans; Middle Aged; Brain Neoplasms - pathology; Magnetic Resonance Angiography; Gadolinium; Male; Necrosis; Organometallic Compounds; Magnetic Resonance Imaging; Brain Neoplasms - secondary; Contrast Media; Aged, 80 and over; Adult; Female; Aged; Diagnosis; Metastasis; Magnetic resonance imaging; Gliomas; Musicians; Abscess; Index Medicus

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