Diffusion-weighted MRI in the evaluation of renal lesions: preliminary results

Abstract

Abstract. The purpose of this study was to evaluate the capability and the reliability of diffusion-weighted MRI in the evaluation of normal kidney and different renal lesions. 39 patients (10 normal volunteers and 29 patients with known renal lesions) underwent MRI of the kidneys by using a 1.5 T superconducting magnet. Axial fat suppressed turbo spin echo (TSE) T 2 and coronal fast field echo (FFE) T 1 or TSE T 1 weighted images were acquired for each patient. Diffusion-weighted (DW) images were obtained in the axial plane during breath-hold (17 s) with a spin-echo echo planar imaging (SE EPI) single shot sequence (repetition time (TR)52883 ms, echo time (TE)561 ms, flip angle590˚), with b value of 500 s mm 22 . 16 slices were produced with slice thickness of 7 mm and interslice gap of 1 mm. An apparent diffusion coefficient (ADC) map was obtained at each slice position. The ADC was measured in an approximately 1 cm region of interest (ROI) within the normal renal parenchyma, the detected renal lesions and the collecting system if dilated. ADC values in normal renal parenchyma ranged from 1. In conclusion diffusion-weighted MR imaging of the kidney seems to be a reliable way to differentiate normal renal parenchyma and different renal diseases. Clinical experience with this method is still preliminary and further studies are required.MR diffusion-weighted imaging (DWI) is widely used in neuroimaging, particularly for the evaluation of acute cerebral stroke, intracranial tumours and demyelinating diseases [1][2][3][4][5][6]. Application of MR DWI outside the central nervous system has been limited by its inherent extreme sensitivity to motion. In the abdomen the use of DWI has been hampered by the presence of spontaneous motion such as respiration, peristalsis and blood flow, which are orders of magnitude greater than diffusional motion and can easily obscure the effect of diffusion. However, recent advances in ultrafast MRI methodologies make it possible to overcome many motion-related problems and to obtain reliable DW images of the abdominal organs [7]. DWI holds great potential for abdominal imaging, in particular for focal lesion detection and characterization, and the evaluation of diffuse parenchymal diseases for which current techniques are often inadequate. Recent studies have already shown the potential value of this method in the evaluation of various renal diseases, such as renal infection, renal ischaemia, pyonephrosis and diffuse renal disease [8][9][10][11][12].The purpose of our study was to evaluate the capability and reliability of MR DWI in the evaluation of normal kidney and of different renal lesions. Materials and methods10 subjects (6 men, 4 women; age range 30-72 years; mean age 50 years) with normal kidneys and 29 patients (16 men, 13 women; age range 45-85 years; mean age 62 years) with known renal lesions previously diagnosed by ultrasound and/or CT, as simple cysts 13 cases; hydronephrosis 6 cases; pyonephrosis 3 cases; solid tumours 7 cases (3 histologically proven renal cell carcin...

Diffusion-weighted MR imaging of normal and abnormal scrotum: preliminary results

“…The use of these sequences may produce image distortion caused by susceptibility artifacts, due to the presence of air and chemical shift artifacts from fatty tissue. [10][11][12][13][14][15][16][17][18][19][20][21][22][23] These artifacts were not seen in the present study, probably because of the lack of neighboring organs in the scrotal area. A relatively low signal to noise ratio and spatial resolution has also been reported with these images.…”

“…Another advantage of echo planar sequences is rapid image acquisition, reducing motion artifacts. [10][11][12][13][14][15][16][17][18][19][20][21][22][23] There were some limitations in this study. First, it was a retrospective review of a small number of patients with a narrow range of scrotal abnormalities.…”

“…[3][4][5][6][7][8][9] The technique due to its wide field of view, multiplanar capabilities, high contrast and spatial resolution has proved satisfactory in the localization of a scrotal mass, in the differentiation of paratesticular masses with respect to tumor morphology and tissue characteristics, in the distinction between benign from malignant intratesticular lesions and in the evaluation of the local extent of the disease in cases of testicular carcinomas. [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] The technique is mainly recommended when sonographic findings are inconclusive or inconsistent with clinical findings. 5,6 In accordance with previous reports, this study demonstrated high accuracy of conventional MR sequences in characterizing both paratesticular and intratesticular mass lesions.…”

“…In agreement with previous study, this study reported reduced ADC values for malignancies. [12][13][14][15][16][17][18][19][20][21][22][23] The decrease of ADC values in testicular neoplasms is related to the histopathological characteristics of neoplastic tissue, that is, increased tissue cellularity, densely packed malignant cells, enlargement of the nuclei, and angulation of the nuclear contour, all causing reduced motility of water molecules.…”

“…The ADC values of malignancies are reported lower than those of benign lesions or normal tissues. [10][11][12][13][14][15][16][17][18][19][20][21][22][23] Published series reported the usefulness of DW MR imaging in the early detection of ischemia in the testis of Wistar rats and in the detection of nonpalpable testes in children. 24,25 To the author's knowledge, there are no reports in the English-language literature, regarding the normal ADC values of the scrotal contents, that is the testis and the epididymis and the ADC values of scrotal pathology.…”