Primary musculoskeletal tumors: examination with MR imaging compared with conventional modalities.

In 176 cases of primary musculo-skeletal tumors, the informative value of magnetic resonance (MR) imaging was compared with that of plain radiographic examination, angiography, scintigraphy, and computed tomography (CT). In all patients the surgical and histopathologic results were known. For bone tumors confined to the bone, MR imaging was excellent for evaluation of intraosseous extent, but it could not be proved significantly better than CT or scintigraphy. MR imaging was inferior to plain radiography and CT for evaluation of calcification, ossification, cortical destruction, and endosteal/periosteal reaction. For soft-tissue tumors and bone tumors with soft-tissue extension, MR imaging was significantly better than the other modalities in all variables examined: delineation between tumor and muscle, tumor and vessel, tumor and fat, tumor and joint, and tumor and bone, as well as depicting intralesional necrosis and bleeding.

Advances in magnetic resonance imaging of the pelvis at 0.15 tesla.

The recent development of improved commercial radiofrequency coils and multiecho, multislice software for low field strength magnetic resonance systems has markedly increased the clinical utility of magnetic resonance imaging (MRI) of the pelvis at low field strengths. An evaluation of 70 patients with a variety of pelvic lesions and 14 normal volunteers who were studied using 0.15 T resistive magnet scanner revealed that anatomic structures and a variety of mass lesions could be clearly depicted in transaxial, sagittal and coronal planes using this updated system. Accurate characterization of lesions was possible in many instances using T2 weighted multiecho scans with echo time (TE) ranging from 30 ms to 120 ms (45 ms-180 ms using a reduced bandwidth technique). T1 weighted multislice scans demonstrated anatomic structures to best advantage and calculation of T1 and T2 relaxation times frequently facilitated more accurate differential diagnosis, particularly in the case of ovarian lesions.

Magnetic resonance characteristics of an abdominal desmoid tumor.

A case of desmoid tumor arising from the abdominal wall is presented. Although the mass was well demonstrated by contrast-enhanced computed tomography (CT), the typical fibroblastic nature of the tumor was best depicted by magnetic resonance (MR) imaging which also clearly showed the classic origin of the tumor from the anterior abdominal wall musculature. The overall extent of the lesion was also best demonstrated by MR imaging using both transaxial and coronal planes. Spin echo sequences with late echoes were useful in confirming the nature of this lesion.

Magnetic resonance imaging of primary musculoskeletal tumors.

Magnetic resonance imaging (MRI) has a very high soft tissue contrast resolution and possibilities of tissue characterization unseen by any other imaging modality. Therefore, it has a great potential for evaluation of musculoskeletal tumors, and the experience in this field is steadily increasing. MRI has now proven to be superior for evaluation of the extent of intraosseous tumor growth, for evaluation of intraarticular involvement of tumor, and for delineation among tumor and muscle, fat, necrosis, and bleeding. The method reveals the neurovascular bundles in such detail that angiography in several cases is not longer necessary. However, for evaluation of calcification, periosteal and endosteal reaction, and new bone formation, the method is inferior to the traditional radiologic modalities, including computed tomography (CT). Concerning tissue characterization, it has been shown that different tumor groups differ in their T1 and T2 relaxation times, but much more research in this area is demanded. The combination of spectroscopy and imaging, still in its infancy, may prove important in this aspect.

Magnetic resonance imaging of bicornuate uterus with unilateral hematometrosalpinx and ipsilateral renal agenesis.

A complex solid and cystic pelvic mass in a young patient was demonstrated by computed tomography (CT) and ultrasound (US). These modalities failed to accurately characterize the solid components as bicornuate uterus and the cystic areas as hemorrhage. Magnetic resonance imaging (MRI) using multislice multiecho spin echo (SE) sequences made it easier to characterize the mass, clearly depicting the abnormality in transaxial and coronal planes and at the same time demonstrating ipsilateral renal agenesis.

Magnetic resonance imaging of the pelvis: evaluation of ovarian masses at 0.15 T.

Seventeen patients with suspected ovarian masses were evaluated by magnetic resonance imaging (MRI). MRI findings were confirmed by surgery (13 patients) or sonography and clinical follow-up (four). The study evaluated MRI characteristics of ovarian lesions using recently developed multislice and multiecho pulse techniques for a 0.15-T system. T1 and T2 relaxation times were calculated in 12 patients and although a range of values was obtained in several disease categories, diagnostic accuracy was frequently improved. MRI appearances tended to vary considerably with different pulse sequences and were particularly complex in patients with endometriosis and cystic ovarian tumors. Shortest calculated T1 and T2 values were found in hemorrhagic cysts in patients with endometriosis. Benign tumors with thick fibrous pseudocapsules had longer T1 values. Inflammatory masses and malignant ovarian tumors had significantly longer T1 and T2 values and relaxation times in a patient with mucinous cystadenoma varied within the complex mass.

MR imaging of uterine leiomyomas and their complications.

Magnetic resonance (MR) imaging in eight patients with uterine leiomyomas and in eight normal female volunteers clearly depicted the size, shape, and position of the corpus uteri and demonstrated adjacent anatomic structures to good advantage in transaxial, coronal, and sagittal planes. Spin echo (SE) with short repetition time (TR) and short echo time (TE) values was judged best for overall delineation of anatomic structures. Longer TR and TE times were used to differentiate myometrium from endometrium. Detection and characterization of complications of uterine myomas were facilitated by the use of multislice/multiecho SE techniques, but in general TE values greater than 60 ms were not needed to differentiate endometrium from myometrium and in most cases did not improve the MR depiction of abnormalities. Calculated T1 and T2 relaxation times from this preliminary study do not demonstrate a clear advantage in further characterizing uterine abnormalities.

Magnetic resonance imaging of the musculoskeletal system.

During the last few years, the interest and experience in magnetic resonance imaging (MRI) of the musculoskeletal system has increased rapidly. Modern equipment with good spatial resolution and multislice, multiecho technique provides detailed information on the joints, soft tissue and spine within a reasonable examination time, both with superconductive and resistive systems. Today, MRI is an established technique for examination of musculoskeletal tumors and aseptic bone necrosis and it has proven to be of great value for evaluation of diseases of the spine and spinal canal. The definite place of MRI within musculoskeletal diagnostic imaging is not yet settled, but its potential is great, and it will have an important role in the future.

Magnetic resonance imaging of bone and soft tissue tumors: early experience in 31 patients compared with computed tomography.

In 31 patients with 21 soft tissue and 10 bone tumors, magnetic resonance imaging (MRI) and computed tomography (CT) were equally effective in delineating the margins of most soft tissue tumors, and the margins of bone tumors from fat and adjacent normal bone. However, MRI was superior to CT in delineating bone tumors from adjacent muscle, and in showing the relationships to bone of the deep margins of some soft tissue tumors. This was true because the quality of CT images around thick cortical bone often was severely degraded by streak artifact, which does not occur in MRI. Excellent anatomic detail was achieved on MRI by spin echo pulse sequences with short repetition times. Bone tumors were delineated best by spin echo 1000/30 images, and soft tissue tumors by spin echo 1000/30 or inversion recovery images.

Magnetic resonance imaging of fluid levels in an aneurysmal bone cyst and in anticoagulated human blood.

Magnetic resonance imaging (MRI) demonstrated a fluid level within an aneurysmal bone cyst (ABC). Since the ABC contained gross blood at operation, an anticoagulated human blood sample was studied by MRI also, and a fluid level was again clearly visible. MRI pulse sequences emphasizing T1 contrast showed the fluid levels most clearly in both the ABC and the blood. Sequences emphasizing T2 contrast showed homogeneous, bright signals in the ABC and in the blood, with no visible fluid level in the ABC and a nearly invisible one in the blood. In the blood sample, the calculated plasma T1 value was 1585 ms, and that of the red cells was 794 ms.

Benign exostoses and exostotic chondrosarcomas: evaluation of cartilage thickness by CT.

Computed tomograms of 16 benign exostoses and 15 exostotic chondrosarcomas were generally accurate in delineating anatomy for purposes of planning surgery, but they were inaccurate in the detection and measurement of the cartilage caps of the lesions. CT studies of 14 of the benign exostoses failed to show any cartilage cap, although the maximum cartilage thickness of these 14 lesions ranged from 0.1 to 2.5 cm pathologically. CT did demonstrate thick cartilage in 14 of the 15 chondrosarcomas, but the CT measurements of maximum thickness often were imprecise. Altogether, 15 CT studies failed to show any cartilage cap; 14 of these lesions were benign. CT did not reliably detect cartilage caps less than 2.5 cm in maximum thickness, and CT measurement of cartilage thickness was imprecise when the cartilage was 1.5 to 2.5 cm thick. For this reason, CT did not solve the difficult problem of distinguishing between benign exostoses with relatively thick cartilage caps and exostotic chondrosarcomas with relatively thin cartilage.

Computed tomography of uterine papillary serous carcinoma.

We describe the CT appearances of a fairly commonly encountered "special variant" carcinoma of the uterine corpus called uterine papillary serous carcinoma ( UPSC ). UPSC closely resembles ovarian papillary serous carcinoma microscopically but CT with contrast can differentiate between these two entities. In addition CT in this patient clearly showed the characteristic spread mode of this particularly aggressive form of endometrial carcinoma. Because UPSC has a significantly higher relapse rate than other histologic types of endometrial carcinoma it is important to recognize it at the time of the CT staging procedure. The spread pattern of UPSC suggests the need for adjuvant irradiation or chemotherapy.

Aggressive fibromatosis: evaluation by computed tomography and angiography.

Fifteen CT scans of 13 patients who had aggressive fibromatosis were generally accurate in showing the extent of disease, although the CT definition of half or more of the margins of nine lesions was poor. Fibromatosis tumors were typically isodense or slightly hypodense with muscle when no contrast medium was used, and they enhanced to hyperdense with better delineation during infusion of contrast medium. Obliterated intermuscular planes did not always signify disease extension; the relationship to bone was often obscured by beam-hardening artifact; and small blood vessels were often invisible. Arteriograms of seven of eight patients showed some hypervascularity and helped to delineate lesions and vessels that were poorly seen on CT scans. In four instances CT findings were clearer, in two instances arteriographic findings were clearer, and twice the findings were equally clear. Three of six bone scintigrams added accurate information about involvement of adjacent bones. Since fibromatosis can microscopically infiltrate beyond the margins indicated by radiographic studies and even by direct palpation at operation, the surgeon should obtain a wide margin beyond the defined tumor limits.

Contrast enhancement of hepatic tumors in CT: comparison between bolus and infusion techniques.

Pre- and postcontrast CT scans of 125 nonselected patients with histologically verified hepatic neoplasms were analyzed. Sixty patients received an intravenous bolus injection of 50-100 ml diatrizoate 60% in 10-20 sec, and 65 patients an intravenous infusion of 300 ml diatrizoate 30% in 5-10 min. Compared to the precontrast examination, a significant improvement in the visualization of hepatic tumors was obtained with both contrast administration methods when the patients were examined before the equilibrium phase (difference in blood iodine concentration between aorta and inferior vena cava of less than 10 H) is reached. The equilibrium phase is reached 2 min after a contrast material bolus and with termination of an infusion. Scanning in the equilibrium phase does not significantly improve visualization of hepatic tumors when compared to the precontrast examination and carries a considerable risk of partial to complete tumor concealment. For similar reasons, concealment of hepatic tumors might also result when intravenous contrast material is used for another radiographic study preceding the CT examination.

Contrast enhancement of focal hepatic lesions in CT: effect of size and histology.

The effect of size and histology on the contrast enhancement of hepatic lesions has been analyzed in this clinical and experimental investigation yielding the following results: (1) The attenuation values of hepatic cysts in patients increase significantly and inversely with their size after contrast enhancement when the cysts measure less than twice the CT-slice thickness. This seems to be caused by partial-volume effect. (2) Experimental tumors of identical sizes and originating from the same cell line can demonstrate different contrast-enhancement patterns. (3) Peak contrast uptake in both experimental and human tumors seems to be inversely related to their size. (4) Compared to liver, contrast washout from experimental and human tumors (presumably the extravascular space) is delayed. The delay in the contrast washout from a tumor seems to correlate with tumor size. These findings suggest that in general, it is not possible to differentiate reliably among various hepatic neoplasms on the basis of their contrast enhancement patterns for the following reasons: (1) Attenuation values of small hepatic neoplasms are distorted by partial volume effect. (2) Tumors of different histologies can demonstrate the same enhancement pattern. (3) Tumors of identical histology and size can demonstrate different enhancement patterns. (4) The enhancement pattern of a tumor changes with growth or size.

Porcine sensitized lymph node cells (immunotherapy) and attenuated irradiation for infiltrative transitional cells 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.

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.

Differential diagnostic problems in the radiologic evaluation of histiocytic lymphoma.

Medical records, pathologic records, an 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.