Magnetic resonance imaging (2)

The introduction of an effective blood test, prostate specific antigen (PSA), has made it possible to diagnose more and more men in an earlier stage where they can be offered potentially curative treatments. The other side of the coin is that if effective diagnostic procedures are used unselectively in elderly men with a short life expectancy, a problem with over diagnosis and over treatment might occur. Thus the same stage of prostate cancer may need different treatment strategies, pending on the patient’s life expectancy. This, and many other issues regarding the disease, is the subject of the EAU guidelines on prostate cancer. G UI DE LI N ES O N P RO ST AT E CA N CE R 10

/pdf/guidelines-on-prostate-cancer-xdnunn4th8.pdf

Guidelines on Prostate Cancer

IN the 12 years since the topic was last reviewed in the Journal,1 prostatic cancer has become the most common newly diagnosed cancer in men It is the cause of death in more than 28,000 men per year, accounting for 11 percent of cancer deaths, third in men after lung and colon cancer2 Important questions remain about the cause and prevention of prostatic cancer, but new advances permit earlier diagnosis and more accurate staging Curative therapy is possible for localized disease with much less morbidity than previously In advanced disease, androgen-deprivation therapy remains the mainstay of treatment Biology and   

Carcinoma of the Prostate

Image analysis and machine learning in digital pathology: Challenges and opportunities

A shielded medical device implanted in a biological organism. The device has a magnetic shield, and the magnetic shield contains a layer of nanomagnetic material; such layer has a morphological density of at least 98 percent; and it is bonded to the medical device by means of an interlayer with a thickness of less than about 10 microns. The nanomagnetic material in such layer has a saturation magnetization of from about 1 to about 36,000 Gauss, a coercive force of from about 0.01 to about 5,000 Oersteds, a relative magnetic permeability of from about 1 to about 500,000, and an average particle size of less than about 100 nanometers.

Magnetically shielded assembly

Endorectal surface coil magnetic resonance (MR) imaging was used to stage the local extent of prostate cancer in 22 patients. The endorectal coil images were acquired with a 10-12-cm field of view and a 4-mm section thickness. All pathologic specimens were reviewed by one pathologist. Endorectal surface coil MR imaging was 82% accurate in the differentiation of stage B from stage C cancer. One case was overestimated, and three cases were underestimated. The three underestimated cases consisted of two cases of microscopic capsular invasion and one case of minimal seminal vesicle invasion. In a comparison of retrospective, blinded readings of endorectal coil and body coil images, there was an average improvement in accuracy of 16% in staging prostate cancer with endorectal coil images.

Prostate cancer: local staging with endorectal surface coil MR imaging.

An endorectal surface coil has been developed to obtain high-resolution magnetic resonance images of the prostate. The probe consists of a surface coil mounted on the inner surface of a balloon. The balloon is concave to ensure tight seating against the prostate. The coil has been used in 15 patients with biopsy-proved prostatic carcinoma and in two healthy volunteers. The axial images were obtained with a 12-16-cm field of view and a 3-mm section thickness. Compared with images obtained with a body coil, the surface coil images better demonstrate prostatic anatomy and pathologic conditions.

Prostate: MR imaging with an endorectal surface coil.

An insertable intracavity probe (10) for use in magnetic resonance imaging of an area of interest in a body cavity particularly the colon, has an elongate shaft with a handle (18) at its proximal end and an inflatable balloon structure (16) at its distal end. The balloon structure has an outer balloon (26) containing a loop-type pickup coil (20) for connection to an interfacing network (12). The coil is sandwiched between two internal separately inflatable balloons (22 and 24), and when the probe is inserted, the coil can be optimally positioned relative to the area of interest by controlled differential inflation of the balloons. The probe also has an insertable rod-like mandrel (56) for providing twisting orbital-type movement of the balloon structure on the shaft, by rotation of the mandrel, useful to steer the probe along curves or bends in the body cavity when it is being inserted. In a modified form of the probe, the mandrel can be used to rotate the coil and the internal balloons as a unit within the outer balloon for optimal in situ angular positioning of the coil.

Externally moveable intracavity probe for MRI imaging and spectroscopy

To study the potential utility of magnetic resonance (MR) imaging in staging colorectal tumors, 15 resected colonic segments containing 17 elevated lesions were examined on a 1.5- or 1.9-T superconductive MR system. The whole intestinal wall was apparent as three or five layers on images obtained with a short repetition time (TR) and short echo time (TE) and as six or eight distinct layers, including the intestinal wall proper as well as an adherent mucus layer and an outer layer of pericolonic fat, on the long TR/TE images. In cases of colonic carcinoma, MR images correlated well with the pathologic findings, including the macroscopic growth pattern, depth of mural invasion, and the presence of foci of calcific tumor necrosis and pools of extracellular mucin (colloid). These features suggest that MR imaging may be valuable in the clinical evaluation of colorectal tumors.

Yutaka Imai

Papers

Prostate cancer: local staging with endorectal surface coil MR imaging.

Prostate: MR imaging with an endorectal surface coil.

Externally moveable intracavity probe for MRI imaging and spectroscopy

Colorectal tumors: an in vitro study of high-resolution MR imaging.

Von aussen bewegbare körpersonde zur mri-bilderzeugung und zur spektroskopie