Derek J. Hamlin

Positive and negative contrast agents in CT evaluation of the abdomen and pelvis

The oral administration of a dilute positive iodinated contrast agent such as 2% Gastrografin is usually necessary to achieve optimal delineation of abdominal and pelvic organs. The amount of contrast agent administered and the timing of its administration depends on the site of suspected disease within the body. The simultaneous administration of antiperistaltic agents intravenously is generally unnecessary when utilizing the modern fast CT scanners. However, contrast agent-induced artifact may at times be troublesome, and we therefore suggest that lesions in the left lobe of the liver be scanned without positive contrast in the stomach. Negative contrast may also be useful in delineating disease: gas (carbon dioxide) has been shown to be useful in evaluating bladder tumors. We have also used air insufflation to facilitate the evaluation of small rectal tumors. Intravenous administration of contrast agent aids characterization of various disease entities and also facilitates the recognition of vascular structures (such as veins and arteries in the peripancreatic region). In our opinion both the infusion and bolus modes of contrast material administration have their place in the evaluation of abdominal and pelvic lesions by computed tomography. Newer techniques such as dynamic CT scanning will probably prove to be valuable both in delineating and characterizing disease.

Modification for Computerized Tomographic Staging of Infiltrative Bladder Carcinoma

Technique modifications for computed tomographic staging of infiltrative bladder carcinoma are aimed at maximizing image quality and reducing artifactual problems, particularly those associated with the effects of motion owing to poor patient cooperation. Patients unable to tolerate a lengthy procedure or the prone position have been studied using a low density contrast technique with controlled bladder distension. Although the intravesical tumor component often is not as dramatically demonstrated as with the gas insufflation technique the accuracy of both staging procedures appears to be high. The tendency towards overstaging is common to bladder opacification and gas insufflation techniques but this may be reduced considerably by bowel opacification when necessary and the use of intravenous contrast enhancement techniques.

Computed tomography of the pelvis: sagittal and coronal image reconstruction in the evaluation of infiltrative bladder carcinoma.

Abstract: The application of reconstructed images in the sagittal and coronal planes is discussed and illustrated with respect to the computed tomographic (CT) evaluation, including staging, of bladder carcinoma. Reconstruction CT was found to be particularly useful in delineating the craniocaudal extent of tumor. In addition, reconstructed images frequently aided the CT evaluation of the relationship of tumor mass to adjacent structures such as seminal vesicles and prostate gland. The improved anatomical orientation achieved by reconstruction was found useful in the presurgical evaluation of tumor site and extent of the lesion.

Computed tomography of bladder: staging of bladder cancer using low density opacification technique.

In the course of computed tomographic (CT) evaluations involving 200 patients with suspected pelvic disease we have found that scan quality is often suboptimal. A preliminary report employing a low density bladder opacification method is presented whereby an indwelling catheter is inserted to control bladder volume and facilitate the instillation of low density iodinated contrast agent (0.6% Renografin-60). The patient remains supine throughout the twenty-five-minute procedure. Observations during the CT staging and follow-up of a controlled group of 8 patients undergoing immunotherapy and/or radiation therapy for bladder carcinoma indicate that this is a simple, safe, and effective staging procedure. We have obtained reliable clinical-radiologic-pathologic corrlation as a result of careful surgical staging and biopsy, followed by open surgery and full pathologic examination. It is hoped that this information will help initiate other similar studies to determine the diagnostic accuracy of this method and thus its use in pretherapeutic evaluation of the bladder lesion and its subsequent response to treatment.

Porcine sensitized lymph node cells (immunotherapy) and attenuated irradiation for infiltrative transitional cell carcinoma of bladder

Thirty-four patients wih infiltrative bladder carcinoma, Stage B2C or higher were treated with immunotherapy and irradiation. Seventeen patients are alive, and 17 have succumbed to their disease. Eight patients underwent cystectomy after immunotherapy and irradiation; 6 of 8 are alive and well at the present time. The technique of immunotherapy is outlined. New methodology for sequential CT scans and scheduled bladder biopsies is mentioned. The 17 patients have survived twelve to sixty-nine months after immunotherapy and irradiation. Downstaging is demonstrated based on sequential CT scans of the bony pelvis and histologic biopsy. The biopsies reveal eosinophilia and multinucleated giant cells, a specific response to immunotherapy. A prospective randomized study will be initiated.

Efficacy of CT scanning in a group of 174 patients with orthopedic and musculoskeletal problems

One hundred and seventy-four patients with orthopedic and musculoskeletal problems received computed tomography (CT) scans between January 1979 and July 1980. There were 34 trauma patients, 35 patients with known or suspected primary tumors, 20 patients with metastases, 18 patients with suspected spinal stenosis, 25 patients with disc problems, five patients with infections, 13 children with congenital anomalies, and 24 patients with miscellaneous problems. The CT scans proved useful in all the pediatric cases, 97% of the trauma patients, and in the majority of patients with tumors. It appears that absolute indications for CT scanning in orthopedic patients include acute trauma to the spine, pelvis, hip, and shoulder girdles as well as in children with congenital spinal anomalies. Relative indications include determining the extent of the tumor and also aiding in the correct approach for biopsying a lesion.

Differential diagnostic problems in the radiologic evaluation of histiocytic lymphoma

Medical records, pathologic records, and radiologic examinations of 112 patients with histiocytic lymphoma (HL) were reviewed. Peripheral lymph node enlargement was initially present in less than 50%, while HL presented as localized intraabdominal or intrathoracic lesions in 29% and 13%, respectively. Diagnostic problems encountered during the radiologic evaluation of patients with HL included the following: 1) Localized intraabdominal and intrathoracic lesions could mimic a variety of diseases, most often carcinoma. 2) Intercurrent (opportunistic) infections, which were commonly found in the lungs, and more rarely in the distal esophagus and bone, could easily be mistaken for HL manifestations. 3) Cytotoxic drugs and/or steroids produced pulmonary infiltrates, gastric ulcers, and collapsed vertebral bodies were often indistinguishable from an HL manifestation. 4) A second malignancy, found in 10% of patients either before or after HL was diagnosed, was difficult to differentiate from HL. 5) Aspiration biopsy of localized intraabdominal or intrathoracic HL under fluoroscopic control was unreliable in establishing the correct diagnosis.

CT, including sagittal and coronal reconstruction, in the evaluation of pancoast tumors

Seventeen patients with histologically proved bronchogenic carcinoma involving the superior pulmonary sulcus (Pancoast tumors) were evaluated by computed tomography (CT), including sagittal and coronal image reconstruction. Compared to conventional radiography, axial transverse CT images provided, in all cases, additional information regarding local tumor extension and metastatic spread. Mediastinal involvement either by lymphangitic spread or direct tumor extension was present in 11 cases. In 4 patients plain films clearly showed mediastinal disease; however, CT more clearly delineated overall tumor extent, thus facilitating improved therapy planning. In a further 4 cases CT showed mediastinal involvement after plain films had been read as normal, and in an additional 3 instances metastatic involvement was either greatly underestimated (2 patients) or overestimated (1 patient) on the plain films. Reconstructed images in sagittal and coronal planes lacked detail but facilitated a three-dimensional concept of tumor extent and relationship of tumor to adjacent structures, particularly major blood vessels.

Updating computed tomography of bladder carcinoma in assessing response to immunotherapy and attenuated irradiation.

Abstract Computed tomography (CT) was utilized as part of the surgical-pathologicradiologic evaluation of 21 patients who were treated for bladder carcinoma with attenuated irradiation and immunotherapy. Fifteen patients had moderately infiltrative (Stage B 2 -C or less) disease, and it was found that a routine high resolution CT technique using a modern fast scanner delineated the tumor in most cases. More accurate assessment of tumor response to therapy and evaluation of tumor progression were facilitated using a gas insufflation technique combined with intravenous contrast infusion. This was followed in selected cases by quantitative measurements of CT attenuation values using a recently introduced CT software program. Using this program, individual pixel values were obtained in selected areas and evaluation of the resulting numerical data and pixel histograms aided in the differentiation of tumor tissue from adjacent bladder wall and mapped out areas of tumor necrosis. Our preliminary observations suggest that quantitative CT studies incorporating assessment of printouts of attenuation values of adjacent pixels within a region of interest will improve the delineation of smaller (B1/B2) lesions and will aid objective characterization of tumor tissue during and following therapy.