Clinical efficacy of computed body tomography, II.

The contribution to diagnostic understanding and therapeutic decision making by computed body tomography (CT) was measured in 623 patients using prospective and retrospective inquiry of referring physicians. CT improved diagnostic understanding in 52% of patients, reassured the physician about previously planned therapy in 43%, improved precision of previously planned treatment in 23%, and contributed to a change in therapy in 14%. There was a significant increase over time in reports of improved diagnostic understanding which was probably related to increasing clinical experience with the technique. However, this improvement in diagnostic understanding did not correspondingly increase the frequency of beneficially altered therapy. CT contributed to a substantial decrease in preplanned invasive imaging tests and a decision not to perform surgery in 19% of patients in whom an operation had been previously planned. The value of a CT examination to patient care varied considerably with the clinical problem; the most consistent contributions were observed in patients with diseases suspected in the mediastinum and retroperitoneum.

Diagnosis of abdominal malignancy by radiologic fine-needle aspiration biopsy.

Fine needle aspiration biopsy in 100 consecutive patients with suspected abdominal malignancy yielded a positive diagnosis in 69 (82%) of 84 patients in cases ultimately proven to have cancer in the area sampled. Of 21 pancreatic cancers, 18 (86%) were detected; 24 (83%) of 29 liver lesions, usually metastases, were identifed; and 16 (78%) of 22 retroperiteonal masses, most frequently metastatic lymph nodes, were correctly diagnosed. Overall success rate for epithelial malignancy was 67 (85%) of 79 and far exceeded the yield in lymphomatous masses where two (40%) of five cases were detected. Several radiologic guidance methods were used including computed body tomography in 41%, ultrasonography in 45%, and fluoroscopy with or without conventional contrast agents in 14%. Complications were negligible. In a subgroup of 20 patients in whom a positive diagnosis was obtained, separate analysis of the cytologic specimen revealed that the first needle pass contained definitive material in 15 (75%) of 20 cases. The results confirm the effectiveness, safety, and wide applicability of fine-needle aspiration biopsy for nonsurgical confirmation of advanced or unresectable intraabdominal malignancy.

Appearance of lymphomatous involvement of the mesentery by ultrasonography and body computed tomography: the "sandwich sign".

A characteristic appearance of lymphomatous involvement of the mesentery is demonstrated by ultrasonography and computed tomography. The presence of a lobulated confluent mass infiltrating the mesenteric leaves and encasing the superior mesenteric artery and veins producing a "sandwich-like" appearance is reported in seven patients with Hodgkin and non-Hodgkin lymphoma. Retroperitoneal adenopathy was present in all seven patients. In six, a correct prospective diagnosis was made and a major revision of therapeutic planning occurred. Laparotomy was deferred in three patients. The anatomy, pathophysiology, and clinical importance are detailed.

Acoustic contrast enhancement: value of several system gain variations in gray scale ultrasonography.

Because of the broad spectrum of echogenicity inherent in the heterogeneous composition of the abdominal viscera, system gain variations may be useful in gray scale ultrasound imaging to improve lesion definition. In general, Anechoic or hypoechoic processes may be accentuated by scanning in the higher gain ranges, while hyperechoic lesions may be better delineated at lower gain levels. Thus adjustments in "acoustic contrast" may supplement and reinforce information derived from an initial standard medium gain scan. Although the liver serves as a model in this report, careful selection of a variety of system gain levels can be helpful in evaluating focal lesions in any organ.

Nonvisualized gallbladder by cholecystosonography.

To further define the significance of gallbladder nonvisualization by cholecystosonography, we studied follow-up data on 25 consecutive patients in whom the gallbladder could not be identified despite adequate fasting. In one patient, intravenous cholangiography demonstrated a large gallbladder but no gallstones. In the 24 cases for which a pathoanatomic diagnosis was established, all but two had diseased gallbladders with obliteration of the lumen. This 88% accuracy for positive prediction confirms results of previous sonographic studies and matches the diagnostic significance of nonvisualization at oral cholecystography. We recommend oral cholecystography for all ultrasonic nonvisualized gallbladders for greater diagnostic accuracy when surgery is contemplated.

Gray scale ultrasound in adnexal thickening: correlation with laparoscopy.

A retrospective comparison between ultrasound and subsequent laparoscopy was made in 70 female patients to evaluate the sonographic features of minimal pelvic disease (in particular, adnexal thickening). The overall accuracy of sonography as compared with laparoscopy was 75 percent (53 of 70), with a true positive rate of 72 percent (40 of 51) and a true negative rate of 68 percent (13 of 19). In this study the concept of clinical or sonographic adnexal thickening did not correlate with observations at laparoscopy. Of the 7 patients diagnosed by ultrasound as having adnexal thickening, only 1 had pelvic inflammatory disease, whereas the other 6 showed no abnormalities at laparoscopy.

Computed body tomography in chronic pancreatitis.

CT of the pancrease permitted correct positive diagnosis in 28/50 or 56% of patients with chronic pancreatitis proved by laparotomy or retrograde ductography. Diagnoses were based on CT identification of one or more specific hallmarks of chronic pancreatitis including calcifications (18/50 or 36%), parenchymal atrophy (7/50 or 14%) and pancreatic duct dilatation (2/50 or 4%), as well as the principal surgical complications, pseudocyst and abscess (15/50 or 30%). In 9 patients, CT disclosed pancreatic calcifications not visible on conventional radiographs. In 32 patients, ultrasound was less informative than CT giving a correct diagnosis in 8 pseudocycts (25%). In the patient with unexplained upper abdominal complaints, a positive CT diagnosis of chronic pancreatitis permits more confident patient management than a negative, or "no tumor" diagnosis rendered by other noninvasive examinations.

Gas in the bile ducts (pneumobilia) in emphysematous cholecystitis.

Gas in the biliary ducts (pneumobilia) was demonstrated in three cases of emphysematous cholecystitis. Pneumobilia is usually secondary to a spontaneous internal biliary fistula or incompetent sphincter of Oddi, and is rarely considered a manifestation of emphysematous cholecystitis. The presence of gas in the biliary ducts in these cases suggests that the cystic duct is patent, allowing gas to escape from the gallbladder lumen. The pathophysiology of emphysematous cholecystitis is discussed and an ischemic etiology considered.

Clinical efficacy of computed body tomography.

A method for assessing the effect of computed body tomography on diagnostic understanding and therapeutic decision making is described and the results in the first 184 patients are presented. The patients' referring physicians provided the primary data used for the evaluation. CT improved diagnostic understanding in 41% of patients, reassured the physician about previously planned therapy in 43%, contributed to a change in therapy in 17%, and improved precision of previously planned treatment in an additional 10%. CT contributed to a decision not to perform surgery in 21% of patients in whom an operation had been provisionally planned While CT can play an important role in patient management, its measured value depends on the clinical problems investigated and the level of efficacy on which it is judged.

Scanning techniques in computed body tomography.

Clinical examinations with the whole body CT scanner require considerable individualization of examination technique in relation to specific organs, anatomic areas, and clinical problems. Careful selection of radiographic factors, patient position, contrast agents, and pharmacologic adjuncts will optimize diagnostic results and patient throughput.