Biomedical subjects
Publications and source records attributed to L Kreel.
Three cases of pleural calcification associated with pancreatitis are reported, each of which showed bilateral basal curvilinear calcification. There was no known history of asbestos exposure. Although pleural effusion due to pancreatitis is well known, pleural calcification has not been recognized previously as a complication of this disease.
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Dual-energy computed tomography (CT) was used to estimate hepatic iron concentration in eight patients with primary haemochromatosis with varying degrees of iron overload. The values corresponded closely with these derived from chemical analysis of liver tissue obtained by biopsy (correlation coefficient 0.993). Dual-energy CT therefore seems to provide an accurate and non-invasive alternative to liver biopsy as a means of measuring liver iron concentration in patients with primary haemochromatosis and possibly other iron overload states.
Retrograde gastric mucosal prolapse into the esophageal vestibule producing incomplete obstruction, following a Heller's procedure for achalasia of the esophagus, is reported.
In a review of 260 cases of lymphoma, there were 6 patients with an aneurysm of the abdominal aorta. In four cases there was surrounding abdominal lymphadenopathy. The diagnosis was established by computed tomography (CT) because of calcification in the aortic wall was visible on the scans in all 6 cases. This calcification was not sufficiently clear to permit identification of the aneurysm on plain films in three of the cases. In two cases without abdominal lymph-adenopathy, contrast-filled nodes delineated the outer margin of the wall of the aorta.
Fifty-five patients with malignant colonic tumors were reviewed, and the CT findings were analyzed, as well as two cases of carcinoid tumors of the terminal ileum. There is increased incidence of recurrence in patients under 60 years of age, and 22% of local recurrences occurred 5 years or later after "curative" surgery. A local recurrence alone was found in 44% of patients, distant metastases alone in 10%, and concomitant local recurrence and distant spread in 46%. Three-quarters of the locally recurrent masses were infiltrative and one-quarter were non-infiltrative. The important infiltrative elements included bone erosion, and 45% of those with bladder infiltration had distant metastases. The finding of hydronephrosis was associated with the presence of a local recurrence mass in all instances, and half of these cases had regional lymphadenopathy with local infiltration. Furthermore, 60% of patients demonstrating hydronephrosis had distant metastases. The most commonly involved organs in distant metastatic spread were the liver and lungs There was a higher incidence of lymphadenopathy associated with pulmonary metastases than with hepatic deposits, which could possibly indicate different routes of spread. CT was found to be particularly helpful in detecting clinically occult recurrent disease. In clinically apparent disease, CT was able to assess the extent of the disease process and it also played a role in the practical therapeutic management of patients.
Tumor ossification or calcification occurring after radiotherapy was shown by computed tomography (CT) in three cases. In both the case within the abdomen and that within the pelvis these changes were also apparent on plain films, but in the third case, involving the nasopharynx, no evidence of calcification was seen without CT. In the two cases of carcinoma, ossification or calcification indicated resolution, but in the case of lymphoma these changes were accompanied by rapid recurrence in adjacent tissue.
Clinical and biochemical information together with good spatial resolution by CT offers final assessment of certain adrenal masses even when their size is 1-2 cm. Moderate sized tumours, i.e. up to 8 cm in size are amenable to accurate definition by CT. In some situations it is the final diagnostic modality of adrenal tumours. Tumour recurrence or deposition in the adrenal area is accurately followed by performing sequential scans. Extension and dissemination of neoplasms beyond the confines of the suprarenal can now be defined more readily by CT. Lipid and blood content of adrenal tumours gives low density areas which can mistakenly be assessed as 'cystic' lesions. Large tumours in the area frequently require additional clinical, biochemical and radiological investigation before diagnostic solution is achieved.
Computed tomography is ideally suited for detecting mass lesions and for distinguishing "solid" from "cystic" masses. In the majority of cases, the recognition of fluid collections is unequivocal and lead to direct management decisions. Subphrenic, intrahepatic, and subhepatic abscesses can be recognized, aspirated, and drained. Using CT control, pancreatic pseudocysts can be managed similarly. Renal cysts can be accurately diagnosed with CT, especially with contrast enhancement, and then even the occasional case in which hydronephrosis may be a problem can be distinguished. Very occasionally, solid tumors containing mucinous material or lipoid can appear as cystic lesions, especially in the suprarenal, ovary, liver, or lymph nodes, and, conversely, abscesses may have higher tissue attenuation values, suggesting a solid lesion. It is most important to ensure that bowel is adequately labeled with contrast so that is is not misdiagnosed as a mass lesion.
The CT features in 30 cases of suspected intra-abdominal abscesses are reviewed. The cases were grouped into proven (24), probable (4), and possible (2) abscess on clinical grounds, and were analyzed according to site within the abdomen. Two cases of carcinoma with fluid collections mimicking abscesses are also discussed. In the appropriate clinical context, abdominal abscess is identified on CT as a circumscribed low-density region within the abdomen. Subphrenic, hepatic, and splenic abscesses were readily recognized without contrast enhancement inthe majority of cases, although contrast enhancement consistently rendered loculation within hepatic abscesses more obvious. Aspiration and drainage under CT control were invaluable in diagnosis, permitting the identification of the causative organism in 18 cases. The precise anatomical detail provided by CT was important in achieving successful catheter placement for drainage.
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In vivo attenuation values of 19 fluid collections in 17 patients were compared with in vitro values obtained on examination of the aspirated fluids within the calibration phantom of an EMI CT5005 body scanner. While the in vitro values showed a 5.2 Hounsfield unit (HU:1,000 scale). difference between cysts and abscesses, spectral errors of up to 28.6 HU were sufficiently large for this distinction to be lost in vivo. Good correlation was found between ascitic fluid protein concentration and in vitro attenuation values, but not with in vivo values. An experimental reconstruction program appeared to give more accurate in vivo results than the standard commercial algorithm. A water control showed errors of similar magnitude to those with the fluid collections and did not provide any simple correction for the errors in the fluid attenuation values. Similar results were found for urine examined in vitro and in vivo. The administration of intravenous contrast agents tended to elevate in vivo fluid attenuation values, but refrigeration for 6 months produced little change in in vitro values.
To assess the full potential of computed tomography (CT) in the investigation and management of malignant lymphomas, a series of 160 patients with both Hodgkin's and non-Hodgkin's lymphomas was reviewed. Eighty-eight patients were newly diagnosed and previously untreated, while the remaining 72 who had already received treatment presented either as problems of management or with suspected recurrence of the disease. Computed tomography compared favorably with lymphography as a valuable investigation in the assessment of abdominal and pelvic lymph node involvement. Furthermore, CT added extra information on the full extent of the disease, particularly in those areas not detectable by conventional studies (high paraaortic, retrocrural, mesenteric, splenic, and hepatic hilar nodes). The overall distribution of lymph node involvement both above and below the diaphragm in the two groups of lymphomas was assessed prior to treatment and any obvious differences noted. At the same time, extranodal involvement was analyzed and found to be more difficult to interpret. The value of CT in changing the staging across the diaphragm was recognized. Clinical, CT, and laparotomy findings were correlated in 22 untreated patients with Hodgkin's lymphoma. In conclusion, the role of CT in the initial treatment planning, in the subsequent monitoring of treatment response, and in the assessment of disease recurrence was evaluated.
Unsuspected intracranial pathology was demonstrated in 12 of 136 chronic schizophrenic patients examined by computed tomography (CT). Seven cases of cerebral infarction were found, and one each of porencephalic cyst, meningioma, cystic enlargement of the pineal body, and two of subdural haematoma. Attention is drawn to the value of CT in demonstrating organic disease in schizophrenia.
Six patients with radiographic evidence of diffuse pleural thickening after industrial asbestos exposure are described. Five had computed tomography of the thorax. All the scans showed marked circumferential pleural thickening often with calcification, and four showed no significant evidence of intrapulmonary fibrosis (asbestosis). Lung function testing showed reduction of the inspiratory capacity and the single-breath carbon monoxide transfer factor (TLCO). The transfer coefficient, calculated as the TLCO divided by the alveolar volume determined by helium dilution during the measurement of TLCO, was increased. Pseudo-static compliance curves showed markedly more negative intrapleural pressures at all lung volumes than found in normal people. These results suggest that the circumferential pleural thickening was preventing normal lung expansion despite abnormally great distending pressures. The pattern of lung function tests is sufficiently distinctive for it to be recognised in clinical practice, and suggests that the lungs are held rigidly within an abnormal pleura. The pleural thickening in our patients may have been related to the condition described as "benign asbestos pleurisy" rather than the interstitial fibrosis of asbestosis.
A portable syringe pump was used to administer glucagon by intravenous infusion in order to achieve bowel paresis during abdominal computed tomography. This technique produced a reduction in glucagon dosage and an improvement in scan quality when compared with intermittent intravenous injection. A smaller reduction in dosage with little change in scan quality was achieved with intramuscular infusion.
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