Anna Perrone

Potential role of fetal cardiac evaluation with magnetic resonance imaging: preliminary experience

To report our experience with magnetic resonance imaging (MRI) in fetal heart evaluation.

Evaluation of normal brain development by prenatal MR imaging.

AbstractPurpose.The aim of this study was to describe the normal pattern of development and maturation of the foetal brain with respect to gestational age as assessed with magnetic resonance imaging (MRI) and to provide an overview of the possibilities of the technique.Materials and methods.Foetal cerebral MRI was performed on 56 pregnant women between 19 and 37 weeks of gestation. Half-Fourier single-shot turbo spin-echo (HASTE), true fast imaging with steady precession (FISP), T1-weighted fast low angle shot (FLASH) two-dimensional (2D) and diffusion-weighted (DW) sequences with apparent diffusion coefficient (ADC) were obtained. Biometric parameters and developmental areas of the cerebral cortex were correlated to gestational age by using the Spearman rank correlation test.Results.We found a negative correlation between the germinal matrix/biparietal diameter ratio and gestational age and a positive correlation between the germinal and cortical matrix when expressed as external intraocular diameter ratio (R=0.452, p=0.02). The cortical mantle was correlated with biometric parameters, such as the biparietal diameter and the frontooccipital diameter, and with gestational age. The interhemispheric fissure, the parietooccipital fissure and the sylvian fissure were detectable by the 22nd week. In the grey matter, the mean ADC values varied from 1.76×10-3 mm2/s (at week 19) to 0.89×10-3 mm2/s (at week 37), whereas in the white matter, the values varied from 2.03×10-3 mm2/s (at week 19) to 1.25×10-3 mm2/s (at week 37).Conclusions.MRI provides a reliable valuation of brain maturation during pregnancy.

Magnetic resonance imaging versus ultrasonography in fetal pathology.

PurposeThis paper describes our experience with magnetic resonance imaging (MRI) in the assessment of fetal anatomical structures and major fetal pathologies.Materials and methodsThe retrospective study included 128 pregnant women between the 22nd and 38th week of gestation. We used the following imaging protocol: T2-weighted single-shot fast spin-echo sequences for all foetuses and, in selected cases, gradient echo with steady-state free precession (SSFP), T1-weighted spoiled gradient echo [fast low-angle shot (FLASH)] with and without fat saturation, and T2 thick-slab sequences with multiplanar technique. In 32 cases, we performed diffusion-weighted sequences with apparent diffusion coefficient (ACD) maps on the brain, the kidneys and the lungs.ResultsWe achieved diagnostic-quality images in 125 of 128 patients; MR image quality was unsatisfactory in three cases only. In 16 cases with previous negative ultrasound (US) findings, MRI confirmed the US diagnosis. MRI confirmed the positive US diagnosis in 67 of 109 cases (61.5%); in 11 cases it changed the US diagnosis, and in 31/109 the examination was negative. In addition, MRI identified other anomalies not recognised during US examination.ConclusionsWith its ultrafast sequences, fetal MRI provides good detail of normal fetal anatomy and allows characterisation of suspected anomalies.RiassuntoObiettivoPresentare la nostra esperienza con la risonanza magnetica nella valutazione delle strutture anatomiche e delle patologie principali nel feto.Materiali e metodiLo studio retrospettivo include 128 donne in gravidanza tra la 22a e la 38a settimana di gestazione. Abbiamo utilizzato il seguente protocollo: per tutti i feti sequenze T2 pesate Single Shot Fast Spin Echo e in casi selezionati sequenze Gradient Echo con tecnica steady state free precession (SSFP), sequenze spoiled gradient echo T1 pesate (Fast Low Angle Shot, FLASH) con e senza saturazione del segnale del grasso e sequenze T2 thick slab acquisite con tecnica multiplanare. In 32 casi, abbiamo effettuato sequenze pesate per diffusione con il coefficiente di diffusione apparente (ADC) su cervello, reni e polmoni.RisultatiIn 125 pazienti su 128, l’esame ha mostrato una buona qualità; solo in 3 casi le immagini RM non sono risultate soddisfacenti. Nei 16 casi già negativi all’ecografia, l’RM ha confermato il risultato ecografico. L’RM ha confermato come positive 67 diagnosi ecografiche su 109 casi (61,5%); in 11 casi, invece, l’RM ha modificato la diagnosi ecografica ed in 31 pazienti l’esame è risultato negativo. Inoltre l’RM ha consentito di riconoscere ulteriori anomalie che non sono state diagnosticate durante l’esame ecografico.ConclusioniL’RM fetale, grazie alle sequenze ultra-fast, consente di visualizzare buoni dettagli dell’anatomia fetale e di caratterizzare sospette anomalie.

Diffusion-weighted MR imaging and apparent diffusion coefficient of the normal fetal lung: preliminary experience.

To assess if a correlation is present between apparent diffusion coefficient (ADC) values and normal lung maturation during gestation to define potential reference values as indicators of the lung development.

MDCT of the Breast

OBJECTIVE The purpose of this study was to evaluate retrospectively the accuracy of low-dose MDCT in the differentiation of breast lesions suspected on mammography and sonography. MATERIALS AND METHODS MDCT was performed on 61 patients with mammographic or sonographic findings suggestive of breast cancer who could not undergo MR mammography. For each lesion, morphologic features, attenuation, and time-attenuation curve pattern were evaluated. The 1-minute cut point of attenuation was analyzed on the images. CT findings were compared with histopathologic results, which were the reference standard. RESULTS Forty-seven of 61 patients underwent surgery, and the pathologic findings revealed 27 malignant and 20 benign lesions. With CT 25 of 27 malignant lesions and all 20 benign lesions were diagnosed correctly. CT had a sensitivity of 92.6%, specificity of 100%, positive predictive value of 100%, negative predictive value of 90.9%, and accuracy of 95.74%. The cutoff attenuation value, which had the best validity for differentiating malignant and benign lesions, was calculated to be 90 H on the 1-minute images. CONCLUSION Our results confirm and strengthen the importance of all imaging parameters and not one in particular. Dynamic MDCT can be used in the evaluation of selected patients with suspected breast tumors.

Fetal MRI with diffusion-weighted imaging (DWI) and apparent diffusion coefficient (ADC) assessment in the evaluation of renal development: preliminary experience in normal kidneys

PurposeThe study aimed to investigate the correlation between apparent diffusion coefficient (ADC) and gestational age by applying diffusion-weighted imaging (DWI) in the study of normal fetal kidneys.Materials and methodsWe performed magnetic resonance (MR) imaging on 88 fetuses (gestational age range 17–40 weeks) after ultrasound had ruled out urinary system malformations. A multiplanar study of the urinary system was obtained by using conventional T2-weighted sequences and echoplanar imaging (EPI). DW sequences with ADC maps were subsequently acquired, and kidney ADC values were correlated with gestational age by diving the fetuses into six groups according to age.ResultsWe found a correlation between ADC values and gestational age. The ADC values, ranging from 0.99 to 1.62×10−3 mm2/s [mean 1.22; 95% confidence interval (CI) 1.19–1.25, standard deviation (SD) 0.147], showed a tendency to decrease with increasing gestational age. The relationship between ADC values and gestational age was expressed by a linear regression equation: ADC (mm2/s)=1.69–0.0169 (GA) (R2=37.7%, R2 ADJ=37.0%, p<0.005, Pearson correlation=−0.614).ConclusionsDWI with ADC mapping provides functional information on fetal renal parenchyma development and may thus become a useful tool in the management of pregnancy and treatment of the newborn child.RiassuntoObiettivoApplicare le sequenze pesate in diffusione (DWI) nello studio dei reni fetali, per valutare l’esistenza di una correlazione fra coefficiente di diffusione apparente (ADC) ed età gestazionale nei feti sani.Materiali e metodiAbbiamo studiato con esame RM 88 feti (età gestazionale 17–40 settimane), già valutati con esame ecografico che escludeva malformazioni del tratto urinario. L’apparato urinario fetale è stato studiato con sequenze T2 pesate ultraveloci; successivamente sono state acquisite sui reni fetali sequenze DWI (con calcolo automatico delle mappe di ADC) ed i valori di ADC messi in relazione con l’età gestazionale, suddividendo i feti in sei gruppi in base all’età gestazionale. La normale funzionalità renale è stata confermata dopo la nascita attraverso dati clinico-laboratoristici ed ecografia renale.RisultatiAbbiamo riscontrato che i valori di ADC, compresi fra 0,99 e 1,62×10−3 mm2/s (media 1,22; 95% CI 1,19–1,25; deviazione standard 0,147) tendono a decrescere con l’aumentare delle settimane di gestazione. La migliore correlazione è stata espressa dall’equazione di regressione lineare: ADC (mm2/s)=1,69–0,0169 (GA) (R2=37,7%, R2 ADJ=37,0%, p<0,005, correlazione di Pearson=–0,614). Conclusioni. Le sequenze DWI ed le mappe di ADC, fornendo informazioni funzionali sullo sviluppo del parenchima renale fetale, risultano di grande utilità soprattutto nella gestione della gravidanza e nel management post-natale.