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Biomedical subjects

T Lorentzen

Publications and source records attributed to T Lorentzen.

12 recordsLinked to original sources
PubMed1992

Local staging of prostate cancer with transrectal ultrasound: a literature review.

A literature review was undertaken to investigate whether transrectal ultrasound can predict the local stage of prostate cancer. Twelve papers were found which correlated ultrasound findings with surgical findings and another paper reported on strategic staging biopsies guided by transrectal ultrasound. Eleven of these papers reported on ultrasound findings in patients in whom digital rectal examination had defined localized disease. One paper compared ultrasound findings and digital rectal findings. One paper indicated that transrectal ultrasound, though not suited to patients with clinically localized disease defined by digital rectal examination, may be superior as the initial staging tool. We conclude that transrectal ultrasound has too low a specificity to upgrade the diagnostic results of digital rectal examination, but that it may be more useful as the primary staging tool and for guidance in strategic staging biopsies.

Humans↗
PubMed1991

[Color Doppler ultrasound. Principles, technique and clinical use possibilities].

The medical ultrasound, the Doppler frequency shift is the difference between the frequency of the transmitted and reflected ultrasound. This is due a relative movement between the reflector (most frequently the red blood cells) and the ultrasound transducer. The ultrasound apparatus registers this difference in frequency and calculates the linear rate of flow employing the Doppler equation. The Doppler analysis is presented acoustically, graphically or by means of a colour code. In pulsed Doppler technique, conventional ultrasound scanning can be combined with Doppler analysis. Important indications are: differentiation between vascular and non-vascular structure, documentation of flow and determination of the direction of flow, diagnosis and quantitation of arterial stenoses and assessment of transplants.

Arterial Occlusive Diseases↗
PubMed1991

Ultrasonically guided interstitial Nd-YAG laser diffuser tip hyperthermia: an in vitro study.

Ultrasonically guided interstitial Nd-YAG laser diffuser tip hyperthermia is a new technique that involves placement of a laser fiber in solid tissue under ultrasound guidance followed by irradiation from within the area to be treated. We have previously described a diffuser tip modification of the bare laser fiber, that proved to produce spherical coagulations of predictable size. In the present paper we describe the development of an ultrasonically guided technique which permits simultaneous laser irradiation and interstitial temperature measurements under real time ultrasound monitoring. The laser lesion appeared on the ultrasound image as a hyperechoic area growing in size with time as energy was applied. Macroscopically the laser lesion emerged as a sphere with a central cavity delineated by a rim of charred tissue and beyond this a larger zone of whitish coagulation. The correlation coefficient (Pearson's r) between ultrasonically and macroscopically measured diameter of the laser lesion was calculated to r = 0.89. It is concluded that ultrasonically guided interstitial Nd-YAG laser diffuser tip hyperthermia may have a potential as a tool in the future treatment of ultrasonically visible neoplasias like liver metastases and prostate cancer.

Animals↗
PubMed1990

[Epidermoid cyst of the testis].

We report a case of epidermoid cyst of the testis. The condition is rare and benign. Conservative surgical treatment is advocated when the diagnosis is confirmed by histological frozen sections.

Adult↗
PubMed1990

[Urinary incontinence. Experiences with the artificial urethral sphincter AS 800].

Since 1983, 62 patients with incontinence of urine (43 men and 19 women) were treated with an artificial sphincter model AS 800. During the period of observation, the artificial sphincters were removed in five patients on account of complications and six patients had died. In 22 patients, a total of 34 operations were required on account of complications. Out of 51 patients with artificial sphincters at the time of this review, 43 (84%) had experienced improvement: 15 (29%) were completely continent and 18 (35%) had only slight stress incotinence. It is concluded that the technical improvement which has taken place has improved the therapeutic results and approximately halved the number of complications requiring treatment.

Adolescent↗
PubMed1990

Transrectal ultrasound findings of prostate cancer mimicking primary rectal tumor.

Two patients with disseminated prostatic cancer underwent transrectal ultrasonographic examination. In the rectal wall, at the prostatic level, tumor infiltration was seen without obvious communication to the prostate. Biopsy demonstrated adenocarcinoma, and immunohistochemic staining for prostatic specific antigen (PSA) was positive. We recommend the application of PSA staining in biopsy specimens of unclear rectal masses.

Adenocarcinoma↗
PubMed1989

[Splenic infarction].

Splenic infarction is a recognized sequel of a number of diseases but, until recently, it has been difficult to verify. Employing the new imaging techniques, the spleen has become diagnostically more accessible and increase in the number of splenic infarctions diagnosed must be anticipated. The commonest basic cause is cardiovascular disease but the etiology may be manifold. Whereas the infarct as such is of lesser significance, splenic abscess, eg after bacterial endocarditis, is a life-threatening condition. The treatment consists of surgical drainage and, frequently, splenectomy. The lethality is reduced from nearly 100% to approximately 10% when the correct treatment is employed.

Humans↗
PubMed1989

[Isodense and isoechoic liver metastases].

An important prerequisite in CT and also ultrasonic scanning in order to recognize pathological space-occupying processes in the liver is that these processes can stand out in the pictures with "another colour" than the surrounding liver tissue. CT and ultrasonic scanning are based on very different physical principles and, therefore, different tissue parameters are registered. It is to be anticipated that the contrast conditions between the liver tissue and tumour tissue in the individual patient are not identical in the two imaging processes. The case histories presented illustrate the fact that liver metastases which merge with the liver parenchyma with one of the methods and are, therefore, not recognized, can sometimes be recognized with the other method.

Adult↗
PubMedDate not supplied

Artificial urinary sphincters. Radiographic evaluation.

A small selected group of patients with urinary incontinence can be treated effectively with an artificial urinary sphincter. Since the fluid in the hydraulic system of this device is radiopaque, radiography is useful in its evaluation. An immediate postoperative radiogram should be performed to control the position and integrity of the system. It also serves as a useful baseline study in case of later complications. It should include radiograms both in the deactivated and activated state. A few cases of tube kinking may be overlooked when exposures in only one projection are used. Experience with 110 implanted sphincters is presented.

Adolescent↗