The use of carbon dioxide in magnetic resonance angiography: a new type of black blood imaging.

The injection of boluses of carbon dioxide (CO(2)) during T1-weighted magnetic resonance angiography (MRA) resulted in sharp depiction of the vascular lumen during the performance of in vitro and in vivo animal experiments. We propose the use of the low-cost, relatively safe CO(2) as a negative contrast agent for MRA and speculate on its use in future interventional MRA.

Do non-specific minimal signs in a biennial mammographic breast cancer screening programme need further diagnostic assessment?

Mammographic features such as small vague densities, indefinable microcalcifications, subtle architectural distortions, alone or in combination, are non-specific appearances for breast cancer. These features sometimes precede malignancy and a decisive strategy on how to deal with non-specific minimal signs in a breast cancer screening programme is therefore desirable. After studying the prevalence of these signs in a Dutch Breast Cancer Screening Centre and estimating the risk of participants with these signs acquiring breast cancer within 2 years, we have developed such a strategy. Non-specific minimal signs were seen on the mammograms of 53 of 500 (10.6%) participants, aged 50-70 years, in this programme. After retrospective analysis of the mammograms of 254 patients with screen-detected or interval carcinoma, non-specific minimal signs were detected in 77 cases. Combining the incidence of breast cancer with the difference between the expected number of non-specific minimal signs in the screening programme and its actual occurrence in previous mammograms of patients with breast cancer, the risk of cancer in women with these signs, additional to that of screened women in general (additional risk), is calculated as being 0.5%. Invasive breast cancer in women with previously detected non-specific minimal signs demonstrated a favourable stage at diagnosis (axillary metastasis in 23% vs 37% in cancers without these previous signs, p < or = 0.05). Our strategy for follow-up in case of non-specific minimal signs remains unchanged because of the low additional risk and favourable staging, and is restricted to an invitation for the next screening round in 2 years time.

The use of local anesthesia in second generation extracorporeal shock wave lithotripsy: eutectic mixture of local anesthetics.

Extracorporeal shock wave lithotripsy (ESWL&) can be painful. Of our population of patients treated with a Siemens Lithostar device 51.4% needed intravenous analgesia. A eutectic mixture of local anesthetics, a hydrophylic cream containing 25 mg. lidocaine and 25 mg. prilocaine per gm., proved to be effective for local analgesia. Therefore, we investigated its effectiveness during ESWL. With randomized, double-blind application the eutectic mixture of local anesthetics and placebo were evaluated in 83 patients according to the percentage of patients who required intravenous analgesia during ESWL. Of 40 patients treated with the eutectic mixture of local anesthetics 12 (30%) needed supplementary fentanyl citrate, compared to 23 of 43 (53%) placebo treated patients. Although there is no statistical significance (p = 0.32), the eutectic mixture of local anesthetics does decrease pain during ESWL and it should be particularly useful for patients in whom intravenous analgesia is contraindicated.

Audex Medical, a new system for digital processing and analysis of ultrasonographic images of the prostate.

By transrectal ultrasonography the volume of the prostate is determined two times using the conventional planimetric method. Thereafter the US scanner is placed in a fixture which is retracted repeatedly. For this a motordrive has been developed. The images of each section are improved by digital processing, and the prostatic outline is determined interactively by developed image processing software. In this manner the total volume of the prostate is calculated. In a post-mortem study prostates of 9 cadavers were measured with the conventional planimetry and by means of digital processing and analysis. The results were compared with the results obtained after removal of the prostate. In a clinical study the prostatic volumes of 20 patients were measured in a similar way. The results of the two methods are compared. Both in the cadaver study and the patient study we found a good correlation between the conventional method and the computerized method. In the cadaver study we noticed a better correlation between the prostatic volume found with the computerized method and the volume obtained after prostatectomy. Also the reproducibility of this method turned out to be better.