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Radiologic findings of six cases of malignancy associated with chronic empyema 5-39 years in duration were reviewed. Pathologic examination confirmed three B-cell non-Hodgkin lymphomas, one round-cell sarcoma, one mesothelioma, and one adenocarcinoma. Retrospective findings on plain chest radiographs suggested the occurrence of malignancy: increased radiopacity in the thoracic cavity, soft-tissue bulgings and/or unsharpness of fat planes in the chest walls, destruction of bone near the empyema, and extensive medial deviation of the calcified pleurae. Computed tomography delineated masses with soft-tissue attenuation more clearly than radiography in all cases. Magnetic resonance images of three cases were informative because empyema cavities were surrounded by low-intensity rims, and two of them showed a signal intensity different from that of necrotic tumors. Scintigraphy revealed increased uptake of gallium in all cases. Ultrasonography was useful for biopsy guidance. Every radiologist should know this entity in observation of chest radiographs obtained in patients with chronic empyema, and further radiologic assessment and aggressive biopsy are recommended if malignancy is suspected.

A case of hepatocellular carcinoma is reported in which a calculated T2 value of the tumor was exceptionally long and differentiation from cavernous hemangioma based on T2 signal intensity was difficult. Pathologically, the mass consisted of dense, homogeneous acinar formation (pseudoglandular type). The T2 prolongation of the mass was probably due to abundant fluid in the acini.

A functional MR study was performed using a 0.064 T permanent magnet MR system. The shoulder joints, elbow joints, hip joints, and knee joints of three volunteers (mean height and weight, 176 cm and 71 kg, respectively) were examined at incremental joint angles in three to eight stages during flexion-extension, abduction-adduction, or pronation-supination movement. Each set of 16 images was obtained in 4 min, 49 s using three-dimensional Fourier transformation methods with gradient echo pulse sequences. The images were evaluated in static mode and sometimes in cine mode. The findings obtained about the physiology of these normal joints was generally compatible with findings previously accumulated in the field of kinesiology. The study suggests that this method can be useful for in vivo study of kinesiology and pathogenesis of diseases and that patients with most types of contracture or deformity can be examined by MR imaging.

Thirty-six patients with hepatic tumors (28 hepatocellular carcinomas, seven cavernous hemangiomas, one metastatic tumor) were examined with serial magnetic resonance (MR) imaging, after a bolus intravenous injection of 0.05 mmol/kg gadolinium-diethylenetriaminepentaacetic acid. A typical MR imaging pattern for hemangiomas (present in five of seven cases [71.4%]) was a lesion of diminished signal intensity on precontrast images, peripheral contrast enhancement during the bolus dynamic phase, and complete fill-in of high signal intensity on delayed scan images. Twenty-eight hepatocellular carcinomas showed a variety of contrast enhancement patterns during the dynamic phase. In 21 patients (75%), there was no area of high signal intensity within the tumor on the delayed phase. A peripheral halo with delayed enhancement was noticed in 12 patients (42.8%) Histologic correlation in hepatocellular carcinomas showed that the degree of contrast enhancement corresponded to tumor vascularity and that the peripheral halo corresponded to fibrous capsular structure.

The computed tomographic (CT) and ultrasonographic (US) appearances of retained surgical sponges are described. In each case, the presence of a sponge was confirmed at repeat operation. CT examinations were performed in nine patients. In six cases, a low-density mass was demonstrated; in two cases, a complex mass with areas of both low and medium density was seen. The remaining case was a high-density mass. After intravenous administration of contrast material, dense and prolonged enhancement of the rim of the mass was noted in five of eight cases. Calcification was found in four cases, and spongiform gas in one. US performed in six patients revealed an echogenic area with strong acoustic shadowing in three cases and a complex mass, a hypoechoic mass, and a cystic mass with irregular internal echoes in one case each. Granuloma caused by a retained surgical sponge should be considered as a cause of an abdominal mass in patients with a history of prior abdominal surgery.

Nambu PVA gel which is produced by repeated freezing and thawing of PVA solution has overcome almost all of the problems which present substances have: (1) It is close to human soft tissue in MRI parameters. (2) MRI parameters (1H density, T1, T2) are adjustable to some extent. (3) It has appropriate physical characteristics. The important problem with PVA gel is long-term stability. It is assumed that this problem can be solved by its periodic calibration and replacement. © 1986 Academic Press, Inc.

Cystic neoplasms of the pancreas are divided into two major groups: microcystic adenomas and mucinous cystic neoplasms. Five microcystic adenomas and seven mucinous cystic neoplasms (three cystadenomas and four cystadenocarcinomas) were examined with both magnetic resonance (MR) imaging and computed tomography (CT). The cystic content was differentiated more easily with MR imaging than with CT. It was homogeneous in four of the five microcystic adenomas, all of which had lobulated borders best seen on T2-weighted images. The mucinous cystadenomas and cystadenocarcinomas were all composed of multiple compartments that varied in signal intensity. The septa, shape, and wall thickness were demonstrated on T1- and/or T2-weighted MR images almost as well as on CT scans. Overall, MR imaging was equal or slightly superior to CT in the diagnosis of pancreatic cystic neoplasms, except in its limited ability to demonstrate calcifications of the tumor wall and septa.

Fourteen patients with various portosystemic collaterals (seven esophageal varices, three paraumbilical veins, two splenorenal shunts, and two mesenteric varices) were imaged with magnetic resonance (MR) imaging using a superconducting imager. Collateral pathways were demonstrated as tortuous structures of no or low signal intensity on spin-echo image, and flow related enhancement did not cause any difficulty in evaluation. Direct sagittal images are especially useful for paraumbilical vein and coronal images for esophageal and mesenteric varix. The clinical role of MR in the assessment of portosystemic collaterals is discussed also in comparison with CT and ultrasound.

Scintigraphic manifestations of fibrous dysplasia were analyzed in 59 lesions of 26 patients (12 monostotic, 14 polystotic). Bone imaging with Tc-99m MDP revealed a high percentage of increased uptake of radioisotope in the lesions of fibrous dysplasia. Four (14%) of 29 cystic lesions and two (7%) of 30 lesions with the appearance of ground glass showed no increase in radioisotope uptake, although roentgenograms showed marked changes. Therefore, care must be taken in the diagnosis of fibrous dysplasia with bone imaging alone. Nuclear methods, however, are indispensable in evaluating the dynamic aspects of bone mineral behavior and in demonstrating disease where none was suspected, or in visualizing polyostotic involvement in those cases where only monostotic disease was suspected clinically. It is concluded that both scintigrams and roentgenograms are complementary procedures in the diagnosis of fibrous dysplasia.

The magnetic resonance findings of two hepatomas treated by embolization are presented. The T2-weighted spin echo images showed an increase in signal intensity in the tumor after embolization. This phenomenon corresponded to a decrease in tumor density on CT and to necrosis observed histologically. Magnetic resonance also demonstrated gas bubbles as low signal foci within the embolized tumor.

Enterogenous cysts are relatively rare causes of spinal cord compression. A case of enterogenous cyst causing compression of spinal cord at C2–3 is presented. Radiological findings, including MRI, are discussed.

Computed tomography (CT) was performed after 65 transcatheter arterial embolizations (TAE) in 50 patients with hepatocellular carcinoma. Nonenhanced high-density areas were seen in the tumors within 3 days in 17/25 cases (though they soon disappeared) and low-density areas within 2 weeks in 62/65. Gas bubbles were seen in these areas within 2 weeks in 60% of embolizations. Within 3 to 6 months after the first TAE, enhanced lesions developed around or inside the low-density areas in 15/22 patients. Complications appearing within 2 weeks included non-enhanced low-density areas in the liver and spleen, gallbladder thickening, swelling of the head of the pancreas, contrast retention in the kidneys and gallbladder, ascites, and pleural effusion.

Seventy-two patients with hepatocellular carcinoma (hepatoma) and 56 with hemangioma were studied with magnetic resonance (MR) imaging at 0.35 or 1.5 T to evaluate the efficacy of T2 values in differential diagnosis. T2 values were calculated with the two-point method. The mean T2 values of hepatoma and hemangioma were 58.9 msec +/- 8.9 and 101.6 msec +/- 25.8 at 0.35 T and 49.1 msec +/- 9.8 and 85.3 msec +/- 21.2 at 1.5 T. The difference in the T2 values for hepatoma and hemangioma was statistically significant (P less than .001) at both 0.35 and 1.5 T. Fifty-three of 56 lesions (94.6%) at 0.35 T and 86 of 102 lesions (84.3%) at 1.5 T were correctly classified when the T2 borderline between hepatoma and hemangioma was set at 80 msec. All misdiagnosed lesions were hemangioma, and all but one were smaller than 2 cm. However, over 90% of lesions smaller than 2 cm were correctly diagnosed when 70 msec at 0.35 T and 60 msec at 1.5 T were used as borderline T2 values. MR imaging with T2 measurement was very useful for differentiating between hepatoma and hemangioma (including small lesions) at 1.5 T as well as at 0.35 T.

Magnetic resonance (MR) imaging of 43 patients with hepatic tumor was performed during suspended respiration using a fast scan spin echo (SE) technique (SE 200/40) with a single excitation. The resulting images were superior in terms of image quality to conventional ones. Due to the lack of soft tissue contrast, 38 patients received Gd-diethylenetriaminepentaacetic acid (DTPA) at 0.05 mmol/kg and serial scanning (CE-MR) was repeated. Twelve of 14 hepatomas showed isointensity or slightly reduced intensity compared with the liver in unenhanced MR. All metastases (nine patients) showed low signal intensity that was statistically significant (p less than 0.001) in differentiating between hepatomas and metastatic liver tumors. With contrast enhanced MR, both hepatomas and metastases showed changes that cannot be further classified until more cases have been examined. In all 12 cavernous hemangioma cases, Gd-DTPA pooling was observed with extremely high contrast, which was a pathognomonic sign. In fact, four cavernous hemangiomas in two patients with a diameter of 1.0 cm were successfully imaged.

The main purpose of this report is to describe our method of MRI tissue characterization studies, which consists of MR imaging of the patient, precision MR imaging of the excised organ, and pathological examination of the organ. We first made small coils to be used with conventional MRI scanners to examine the excised organs. In order to make it easier to understand the effectiveness of our method, three illustrative case reports of abdominal or pelvic tumors were presented as examples of the tissue characterization studies. In conclusion, this method seemed very useful and, in addition, it was found that this small coil technique has several advantages in other applications.

The authors retrospectively evaluated magnetic resonance (MR) images obtained at 1.5 T in 233 patients with portal hypertension and 91 subjects without it and pathologic findings in four resected spleens (one normal). Multiple, tiny (3-8 mm in diameter), low-intensity spots in the spleen were observed in 21 of 233 patients. Among the imaging studies performed in these 21 patients, the spots were seen on five of 14 T1-weighted images, 11 of 20 proton density images, and 12 of 20 T2-weighted images obtained with spin-echo techniques and on 14 of 14 fast-scan images obtained with gradient-echo rephasing. MR images in the 91 subjects did not show such lesions. MR images of the three spleens resected from patients with portal hypertension showed the low-intensity spots, which corresponded to siderotic nodules found at pathologic analysis. Despite limited pathologic confirmation, siderotic nodules (so-called Gamna-Gandy nodules) are considered the most likely cause of multiple low-intensity spots in the spleen.

Fifty-three patients who had hepatic tumors (24 hepatomas, ten metastases, and 19 cavernous hemangiomas) underwent MR imaging using a 0.35-T superconducting imager. The transverse relaxation time (T2) was calculated from a pair of spin echo images (repetition time [TR] of 1600 msec) with echo delay times (TE) of 35 and 70 msec. The computed T2 value was obtained in a fashion similar to that used to obtain CT numbers with region-of-interest cursors. The mean T2 was 59 +/- 9 msec in hepatomas, 64 +/- 15 msec in metastases, and 100 +/- 30 msec in hemangiomas. The difference between the T2 of hemangioma and that of liver malignancies was statistically significant (P less than .001); however, differentiation between hepatoma and metastases was not possible. The T2 was shorter than 80 msec in all 24 hepatomas and in nine of ten metastases, and was longer than 80 msec in 16 of 19 hemangiomas. Forty-nine of 53 cases (92%) were correctly classified when the borderline of T2 between hemangioma and hepatic malignancies was set at 80 msec. MR with T2 calculation was valuable in differentiating between hemangioma and hepatic malignancies.

Marked accumulation in lung and liver of intravenously--injected 99mTc-microaggregated human serum albumin (liver imaging agent) was observed in rats pretreated with the subcutaneous injection of microaggregated or macroaggregated human serum albumin, whereas accumulation of 99mTc-microaggregated human serum albumin was observed only in the liver of rats pretreated with plain human serum albumin or in non-treated control rats. The activity of the intravenously-administered 99mTc-sulfur colloid was concentrated in the liver and spleen only and not in the lung, of rats previously treated with human serum albumin, microaggregated human serum albumin, or macroaggregated human serum albumin. These observations suggest that the specific accumulation of microaggregated human serum albumin in the lung of rats pretreated with aggregated albumin is due to rapid in vivo clumping of injected particles, possibly due to antigen-antibody reaction.

The plan radiographs and computed tomography (CT) scans of 12 children with abdominal neuroblastoma were reviewed to evaluate the incidence and shape of calcification in the tumor. Calcifications were detected in 7 cases by plain radiographs and in 10 by CT. Small dotted and thin ring calcifications were better shown by CT. Ring calcification does not appear to be as rare as has been reported. It is emphasized that all ring calcifications in the vicinity of adrenal glands are not benign.

Computed tomographic (CT) and ultrasonographic (US) images of 17 patients with septate cystic lesions in the upper abdomen were reviewed. US was superior to CT in detecting septation and its presence suggested that the ‘cyst’ was neoplastic in nine. CT plays a complementary role in differentiating cystic lesions.

Longitudinal relaxation times (T1) of 20 brain tumors were calculated in vivo using a whole-body magnetic resonance unit with a 0.15-T resistive magnet. Images employing standard inversion recovery pulse sequences with different intervals between the 180 degrees pulse and selective excitation pulses were compared on every point of the 256 X 256 pixel matrix. Tumor, white matter, and gray matter were sampled from each patient from the computed T1 image for T1 measurement. Astrocytomas, neurinomas, and metastatic tumors showed longer T1 values than did meningiomas. Lipomas had the shortest T1s. It is concluded that it is difficult to predict histological types of brain tumors by the measurement of T1 alone because of the wide variation in relaxation times, but measurement of T1 can be helpful in differentiating brain tumors when additional information about the patient's condition is known.

This report describes the magnetic resonance (MR) demonstration of portal vein tumor thrombus (PVTT) in hepatocellular carcinoma (HCC). In two cases of HCC with PVTT diagnosed by angiography, MR demonstrated PVTT as areas of increased MR signal in the portal vein. Our limited experience suggests the potential utility of MR imaging for diagnosis of PVTT.

Fifteen patients with primary intrahepatic biliary malignancy (cholangiocarcinoma in 13, biliary cystadenocarcinoma in two) were examined by computed tomography (CT). The CT features were classified into three types: (A) a well-defined round cystic mass with internal papillary projections, (B) a localized intrahepatic biliary dilatation without a definite mass lesion, and (C) miscellaneous low-density masses. Intrahepatic biliary dilatation was noted in all cases of Types A and B and half of those of Type C; dilatation of extrahepatic bile ducts occurred in 4/4, 1/3, and 0/8, respectively. CT patterns, such as a well-defined round cystic mass with papillary projections or dilatation of intra- and extrahepatic ducts, give important clues leading to a correct diagnosis of primary intrahepatic biliary malignancy.

A case of enormous intrahepatic shunt between the portal vein and the hepatic vein is described. The lesion was successfully treated by embolisation using stainless steel coils on two occasions, after demonstration by percutaneous transhepatic portography (PTP).

We describe an application of simple scintigraphic localization of therapeutic gelatin emboli during and after transcatheter arterial embolization using gelatin particles labeled with technetium 99m. This scintigraphy required an additional 15-30 minutes and can be useful for prevention of serious complications and for early detection of adverse embolisms.