Biomedical subjects
Publications and source records attributed to D O Cosgrove.
In this review article some of the commoner imaging techniques currently available for investigating surgical patients are described. In particular the uses and limitations of ultrasound and radionuclide techniques including emission tomography are discussed.
The ultrasound findings of the pelvis, upper abdomen and peritoneal cavity were correlated with second-look laparotomy in 85 patients with Stage III or Stage IV ovarian carcinoma. High values of accuracy were obtained for the pelvis (90%) and liver (91%) but ultrasound was insensitive to peritoneal disease unless ascites was present.
Ultrasound findings of 39 spleens and 68 livers in which histology was obtained at laparotomy or autopsy within a month of the examination and four livers in which abnormalities were found clinically by other methods during long-term follow-up were reviewed to evaluate the various sonographic appearances and the accuracy in detecting involvement of the spleen and liver. Only one out of 17 positive spleens had definite ultrasonic focal lesions. Not only small splenic Hodgkin's foci but also larger ones were overlooked. Of 10 positive livers, six showed diffuse inhomogeneity throughout the liver, two showed multiple, well-defined, echo-poor lesions but two showed no significant ultrasonic abnormality even in retrospect. No correlation was found between the type of Hodgkin's disease and the ultrasonic appearance of involved livers. Ultrasonic examination, however, could differentiate other liver abnormalities, such as fatty changes, a cyst and a thrombosed haemangioma from infiltration of Hodgkin's disease. In one case, splenic lesions became echogenic following-chemotherapy.
The hundred and fifty-seven ultrasonographic examinations were carried out in 200 patients with testicular tumour. In 16 cases (8.0%) liver metastases were demonstrated. There were three main patterns: well- or ill-defined echopoor lesions, well-defined echogenic lesions, and "target" lesions. Echopoor liver lesions were found in metastatic seminoma, whilst metastatic teratoma may give any of these three patterns. The value of ultrasound for evaluating the therapeutic response of hepatic metastases from testicular tumour is discussed.
Flowing "particles" have been observed within abdominal veins using high-resolution real-time scanners. Experimental models in which fluids of different composition were infused into each other show strong echoes corresponding with visual laminations before complete admixture has occurred. Interfaces between different fluids within the physiologic range seem adequate to account for these echoes. As predicted by this observation, the laminar flow echoes are seen downstream of junction sites where blood different compositions flows together, notably at the renal and hepatic vein junctions with the inferior vena cava, but the phenomenon is not seen in arteries.
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Tumour invasion of the inferior vena cava (IVC) is a complication of retroperitoneal tumours that can be identified at the time of ultrasound B scanning. We have recognized nine patients with proven IVC tumour thrombus from such tumours and have noted several common ultrasound features. Six of these cases were associated with renal carcinoma, two with metastatic teratoma and one with rhabdomyosarcoma. The typical appearance included abnormal echogenic solid material in the lumen of the vessel. In sagittal section the anterior wall was domed as it stretched over the thrombus, and on real time scanning there was loss of the normal venous pulsations. Although similar abnormalities occur with non-tumour thrombus, the presence of these typical features in association with a retroperitoneal tumour is likely to represent tumour invasion of the IVC, an important observation for accurate staging and subsequent management.
In a series of twenty-six patients with Stage III or IV carcinoma of the ovary, results of ultrasound examination of the pelvis and abdomen were correlated with second look laparotomy. All of these patients had responded clinically to a course of chemotherapy. Elective surgery was used to restage and debulk tumour. Ultrasound examination was done before surgery. Ultrasound was sensitive in detecting ovarian tumour in the pelvis and had an 84 per cent correlation with laparotomy. It was also sensitive in detecting liver and right diaphragmatic metastases with a 92 per cent correlation with the laparotomy findings. However, it consistently failed to detect intraperitoneal spread except when disease was gross or when it could be predicted by the presence of ascites. The correlation with laparotomy in this situation was only 36 per cent. This is to be expected as the size of most peritoneal deposits is below the resolution of ultrasound. These lesions, however, are easily detected by laparoscopy. These findings suggest that ultrasound has an important role in the management of advanced carcinoma of the ovary.
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Grey-scale ultrasound tomography was used to examine the liver and biliary tree of 100 consecutive unselected jaundiced patients in a prospective study. It was successful in differentiating between hepato-cellular and obstructive jaundice in 94%. It precisely localised the site of obstruction in 75% of those patients with enlargement of the head of the pancreas from either carcinoma or gall-stones impacted in the Ampulla of Vater. This figure was reduced to 60% when all cases of obstruction were considered. Cirrhosis and chronic active hepatitis were found to be associated with an abnormal pattern of echoes within the liver. These echoes were stronger and more numerous than normal. This association was not apparent with drug-induced cholestasis or acute viral hepatitis. Grey-scale ultrasound tomography is quick, safe and completely non-invasive. It should be the initial investigation of choice in the differential diagnosis of jaundice. When precise localisation of an obstruction is not possible after a repeat attempt, then percutaneous transhepatic cholangiography should be considered.
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Gas in the biliary tree has a striking but not unique ultrasonic appearance consisting of acoustic shadows trailing behind well-defined discrete high amplitude echoes deep within the liver parenchyma, and may be mimicked by intrahepatic gall stones and calcified tumours and granulomas. It interferes with assessment of liver structure, and renders ultrasound B-scan unreliable for the detection of liver metastases. Computed tomography remains unaffected by biliary gas.
The para-aortic region has been investigated with ultrasound in 95 patients with testicular teratoma seen in the testicular tumour unit between 1973 and 1976. The liver was assessed in 110 patients. The technique has provided useful and reliable information. Para-aortic ultrasound can provide more information than existing diagnostic methods and is particularly useful for defining the volume of metastatic nodal masses. Its role should be regarded as complementary to that of lymphography. Ultrasonography is particularly useful to the radiotherapist since it can define the volume and limits of the tumour and thus influence choice of therapeutic approach and radiation planning technique. Ultrasound is also valuable in the assessment of response to treatment and in monitoring the patient during the subsequent follow-up period.
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The brightly echogenic appearance of the diaphragm on routine clinical scans is not easily reconciled with the well-documented echo-poor appearance of muscle elsewhere in the body. A series of specimens of normal human diaphragm freshly excised at autopsy were suspended in a water bath. Articulated arm scans were done varying the angle of the incident beam to the specimen by 5-degree increments and recording the maximum attenuation which allowed visualization (ie, an extinction point). This was accomplished for intact diaphragm, peritoneal membrane alone, and diaphragmatic muscle alone with both membranes stripped. The bright specular echoes seen are due almost exclusively to the membranes (parietal pleura and peritoneum) and the diaphragmatic muscle itself produces only low-level scattered echoes as elsewhere. However, these scattered echoes account for persistent visualization of the diaphragm at steep angles of the incident beam. A considerable portion of the in vivo thickness of the diaphragmatic echo complex is, therefore, produced by diaphragm-lung interface.