Multimodality approach to staging renal cell carcinoma

Renal imaging has dramatically improved since the introduction of ultrasound (US), computed tomography (CT), and most recently magnetic resonance (MR) imaging. US and MR imaging are ideal for patients with compromised renal function preventing administration of iodinated contrast material or those who have experienced reactions to contrast. Staging errors occur due to limitations in assessing microscopic tumor invasion of the renal capsule and perinephric fat, detecting metastatic deposits in normal sized lymph nodes and differentiating inflammatory hyperplastic lymph nodes from neoplastic ones. These limitations are shared by US, CT, and MR imaging. Vascular invasion by tumor can be evaluated by all imaging modalities including venography. The advantages and limitations of each examination will be presented.

Current state of MRI in renal mass diagnosis and staging of RCC

Renal imaging has been enhanced by the introduction of ultrasound (US), computed tomography (CT), and magnetic resonance imaging (MRI). Each of these imaging modalities represents a unique contribution to detection and staging of renal cell carcinoma. MRI offers several advantages, specifically, determination of tumor origin, evaluation of vascular patency, detection of lymph node metastasis, and evaluation of direct tumor extension into adjacent organs.

The male pelvis

Pelvic MRI yields images with excellent anatomic resolution because of limited motion and large signal differences (contrast) between fat, muscle, and organs containing fluid or mucous. Although MRI is not appropriate in screening for pelvic malignancies and is unreliable for tumor detection, it does offer superior delineation of the extent of disease and has become the procedure of choice for pelvic tumor staging.

MRI of the scrotum

Surface coil magnetic resonance (MR) imaging of the scrotum allows differentiation of the testis, epididymis, and spermatic cord. Intratesticular and extratesticular lesions are demarcated by the tunica albuginea. The sensitivity of MR is very high for detection of scrotal abnormalities but is non-specific since it is unable to distinguish primary testicular tumors from benign lesions. Undescended testes which lie proximal and distal to the internal inguinal ring are well visualized by MR imaging. The advantages of MR imaging in locating undescended testes is that it is noninvasive, without ionizing radiation, and capable of multiplanar images.

Current concepts in sonographic diagnosis of fetal renal disease

The fetal kidneys and bladder are usually visible by 15 weeks' gestation on sonograms. The authors present their experience with the diagnosis of renal abnormalities in the fetus.

Undescended testis: value of MR imaging

Magnetic resonance (MR) imaging was performed in 32 male patients, 20 with no abnormalities and 12 with clinically suspected undescended testes. The results were compared with ultrasonographic, computed tomographic, clinical, and surgical findings. The undescended testes were unilateral in eight patients (one had testicular duplication) and bilateral in four. Of 16 undescended testes, 15 were correctly identified on MR images. One intraabdominal testis was not seen. Testis-fat contrast at 0.35 T was optimal with a short repetition time (TR) and a short echo time (TE). At 1.5 T, good contrast was achieved with short TR/TE sequences, but the contrast was even more pronounced with even longer TR/TE parameters. In seven patients with unilateral undescended testes, the undescended and contralateral testes showed symmetrical tissue signal intensity on both T1- and T2-weighted images. In three, the undescended testis was of lower signal intensity, suggesting atrophy. MR imaging promises to become an important diagnostic tool in the detection of undescended testes.

Correlation of transrectal sonographic findings in patients with suspected and unsuspected prostatic disease

Previous reports describing the diagnostic accuracy of transrectal sonography have not documented the specificity of differentiating abnormal internal echoes of the prostate. To determine the specificity of the examination, a prospective study was designed to correlate sonographic findings with histological diagnoses. Gray scale transrectal sonography was performed on 228 patients and the scans were reviewed without clinical information. The sensitivity (true positive rate) was confirmed by histological evaluation in 121 cases to be 90 per cent. The specificity (true negative rate) was determined by histological evaluation as well as subsequent clinical followup to be 60 per cent. Our experience is similar to that of others showing transrectal sonography as a sensitive diagnostic tool. The relatively low specificity demonstrates the difficulty in differentiating the abnormal internal echoes of the prostate, representing malignant and nonmalignant prostatic disease processes.