Commonly encountered adrenal pseudotumours on CT

There are a variety of causes of adrenal pseudotumours on CT, including gastric diverticulum, prominent splenic lobulation, upper-pole renal mass, pancreatic mass, hepatic mass and periadrenal varices. These adrenal pseudotumours can be elucidated by multiplanar reconstruction using CT and MRI as well as from the axial images.

CT demonstration of dilated gonadal vein as a portosystemic shunt of mesenteric varices

PURPOSE

The purpose of this work was to assess CT demonstration of the enlarged gonadal vein as a portosystemic shunt of mesenteric varices.

METHOD

The clinical records and CT images of eight patients with angiographically confirmed mesenteric varices were studied retrospectively. We measured the size of the right gonadal vein of these eight patients and also measured the size of the right gonadal vein in 60 patients without mesenteric varices.

RESULTS

In all eight patients, CT demonstrated that the mesenteric varices drained into the inferior vena cava through the dilated right gonadal vein (diameter 6-10 mm) in all and that the left gonadal vein was not dilated (diameter 2-3 mm). In 60 patients without mesenteric varices, the diameter of the right gonadal vein was 1-5 mm.

CONCLUSION

CT demonstrates the dilated gonadal vein as a portosystemic shunt of the mesenteric varices. Awareness of a dilated gonadal vein in patients with portal hypertension may be helpful to consider the possibility of mesenteric varices.

Fast MRI in obstetric diagnoses

This article describes the fast MRI of fetal abnormalities and placental anomalies in evaluation of the usefulness of fast MRI in obstetric diagnoses. Fast MRI provides excellent resolution for imaging fetal and maternal anatomies without the need for sedation. Fast MRI is therefore useful to clarify diagnoses suggested by equivocal ultrasonographic findings and to obtain additional information for prenatal counseling and management.

Helical CT demonstration of dilated right inferior phrenic arteries as extrahepatic collateral arteries of hepatocellular carcinomas

PURPOSE

The purpose of this work was to demonstrate the appearance of the right inferior phrenic artery (RIPA) on CT in patients with hepatocellular carcinoma (HCC).

METHOD

We assessed the biphasic helical CT scans using 10 mm collimation in 16 patients with arteriographically proven HCCs supplied by the RIPAs. Size of the right and left inferior phrenic arteries and origin of the RIPA were evaluated and correlated with arteriographic images.

RESULTS

Helical CT showed dilated RIPAs on the right diaphragmatic crus as foci of high attenuation on arterial-phase images in all patients. Diameter of the RIPA (average 3.3 mm) was larger than that of the left inferior phrenic artery (average 1.5 mm). The origin of the RIPAs was correctly predicted in 13 of 16 (celiac artery 6, abdominal aorta 5, right renal artery 2) patients.

CONCLUSION

Asymmetric dilatation of the RIPA as an indicator of extrahepatic collateral of HCC can be demonstrated on the right diaphragmatic crus with arteriographic images of biphasic helical CT.

Diffusion-weighted echo-planar MR imaging: clinical applications and pitfalls -- a pictorial essay

Diffusion-weighted imaging (DWI) provides unique information about various pathological changes of the brain. DWI is sensitive for the detection of hyperacute infarcts, and useful in distinguishing acute or subacute infarcts from chronic infarcts. DWI is useful in differentiating cytotoxic edema from vasogenic or interstitial edema, which may help to determine prognosis. DWI is useful in differentiating cystic or necrotic tumors from abscesses or epidermoids. DWI can discriminate nonenhanced tumor infiltration from vasogenic edema, and differentiate dysmyelination from demyelination.

Demonstration of aberrant hepatic and gastric arteries with helical CT

RATIONALE AND OBJECTIVES

To assess the demonstration of aberrant hepatic and gastric arteries with routine axial biphasic helical CT.

METHODS

The arterial-phase images of biphasic helical CT were reviewed to evaluate aberrant hepatic and gastric arteries in 166 patients with hepatocellular carcinomas. Biphasic (30 and 70 seconds) helical CT was performed with 10 mm of collimation. The results were compared with angiography performed within 2 weeks after this CT.

RESULTS

Aberrant hepatic arteries were identified by CT in 38 patients and by angiography in 43 patients (38/43, 88%). Aberrant left gastric arteries were identified in three patients by angiography and by CT (3/3). Careful observation of the fissure for the ligamentum venosum and portacaval space was useful for the detection of these arteries.

CONCLUSIONS

Aberrant hepatic and gastric arteries were well demonstrated with routine axial biphasic helical CT. This may be useful for the surgical and transcatheter management of hepatic tumors.

[CT findings of localized lymphatic spread of lung cancer: correlation with pathologic findings]

PURPOSE

The appearance of localized lymphatic spread of lung cancer as evaluated by computed tomography (CT) was correlated with the pathologic specimens in 178 patients. Clinical significance was also studied, with emphasis on nodal staging (N factor).

MATERIALS AND METHODS

Eighteen of 178 patients histopathologically demonstrated severe lymphatic spread of lung cancer along the bronchovascular bundles. CT findings of localized lymphatic spread of lung cancer and nodal staging of 18 patients were retrospectively reviewed and compared with 160 patients with no severe localized lymphatic spread of lung cancer.

RESULTS

All 18 patients with severe lymphatic spread showed linear opacities extending from the tumor to the pulmonary hilum or peripheral pleura depending on the location of lung cancer. Ten of the 18 patients also showed regional thickening of bronchovascular bundles. The nodal staging of these 18 patients was more aggressive than that of other patients without severe lymphatic spread.

CONCLUSION

If linear opacities and regional thickening of bronchovascular bundles extending from the tumor to pulmonary hilum or peripheral pleura are demonstrated on CT, severe lymphatic spread of lung cancer can be strongly suspected, and lung cancer staging should be done carefully.

Hypertrophic cardiomyopathy with apical left ventricular aneurysm

We report a case of hypertrophic cardiomyopathy (HCM) with apical left ventricular aneurysm, which is difficult to review because cases are so rare. A 54-year-old Japanese man was first found to have an electrocardiographic abnormality (T-wave inversion at rest) 19 years ago, and non-obstructive apical HCM without identifiable cause was diagnosed by echocardiography, left ventriculography, and clinical findings. After 19 years, he was admitted because of repeated episodes of palpitation and chest oppression at rest. Widespread left ventricular hypertrophy from the anteroseptal wall to the apex with an apical left ventricular aneurysm was detected by echocardiography, left ventriculography, and cardiac magnetic resonance imaging. Histologic examination of the hypertrophic apical myocardium surrounding the aneurysm showed that the myocardial tissue had been extensively replaced by fibrous tissue containing hypertrophic myocardial fibers, and uptakes of [123I]-metaiodobenzyl guanidine (MIBG) and [123I-] beta-methyliodophenyl pentadecanoic acid (BMIPP) in single-photon emission photography images were reduced despite high myocardial perfusion. On the other hand, histologic examination of the hypertrophic anterior wall revealed myocardial hypertrophy with disorganization; myocardial perfusion and the uptakes of MIBG and BMIPP were preserved. Abnormalities of myocardial fatty acid metabolism and sympathetic neuron activity with preserved perfusion flow and histologic changes such as fibrosis in the apical wall are indicative of apical myocardial injury or ischemia (infarction) without coronary artery stenosis; apical aneurysm may have occurred in severe apical HCM with cavity obliteration up to the midventricular level.

Delayed adverse reactions to nonionic monomeric contrast-enhanced media

RATIONALE AND OBJECTIVES

A delayed adverse reaction is one occurring more than an hour after injection of contrast media. The frequency and symptoms of delayed adverse reaction to nonionic contrast media still are not well established. The purpose of the study is to clarify the frequency and symptoms of delayed adverse reactions using nonionic monomeric contrast media.

METHODS

Patients studied by computed tomography (CT) were the subject of the investigation. Delayed adverse reactions were compared between the group receiving CT without contrast injection and the group receiving contrast injection.

RESULTS

Delayed adverse reactions were noted in 293 of 2370 patients (12.4%) in the group with enhanced CT and in 93 of 907 patients (10.3%) in the group with unenhanced CT. The frequency of delayed adverse reaction to nonionic contrast media was 2.1% (12.4% - 10.3%; P = 0.094). None of the risk factors were related with the incidence of delayed adverse reaction. The most common delayed adverse reaction was a mild skin reaction, which occurred within 24 hours after injection of contrast media.

CONCLUSIONS

The frequency of delayed adverse reaction to nonionic monomeric contrast media was 2.1%; the most common reactions were itching and limited urticaria.

Migration of Gianturco expandable metallic stents in the upper trachea

Endotracheal expandable metallic stents have been shown to be useful in treating malignant tracheobronchial stenosis. We report two cases of early stent migration in the upper trachea after what appeared to be a successful stent placement. We conclude that care should be taken when placing Gianturco stents across short, extrinsic, stenotic lesions with smooth mucosa located in the upper trachea because they have a tendency to migrate.

Magnetic resonance imaging of thymic epithelial tumors

The authors review their experience with magnetic resonance imaging (MRI) of the thymus and discuss the appearance of thymic epithelial tumors where MRI is clinically useful. Detailed descriptions of MRI findings in benign thymomas, invasive thymomas, and thymic carcinomas are provided. Most benign (noninvasive) thymomas appear with a slightly higher signal intensity than that of muscle on T1-weighted images. On T2-weighted images, thymomas have an increase in signal intensity on both T1- and T2-weighted images. Neither fibrous septa nor lobulated internal architecture can be detected on MRI. Gd-DTPA-enhanced MR images show homogeneous enhancement. On the other hand, invasive thymomas show the same signal intensity as benign thymomas, both on T1- and T2-weighted images. However, invasive thymomas appear inhomogeneous in signal intensity on T2-weighted images. T2-weighted images also show a lobulated border, fibrous septa, and lobulated internal architecture, characteristic of most invasive thymomas. Irregularity of tumor margins indicating invasion into surrounding structures is noted in some cases of invasive thymomas. Exceptionally minute thymomas (< 1 cm in diameter) show a different signal intensity on MRI as compared to those of usual thymomas: both T1- and T2-weighted MR images show a low signal intensity mass with irregular or unclear borders. Histopathologically, these minute thymomas contain numerous tiny cysts and/or abundant collagenous tissues. Generally, thymic carcinomas, except carcinoid tumors, appear with a relatively low signal intensity on T1- and T2-weighted MR images in comparison to those of thymomas. In particular, well-differentiated squamous cell carcinomas appear with a low signal intensity on both T1- and T2-weighted images. Abundant collagenous tissue may be a causative factor for the low signal intensity on T2-weighted MR images. Thymic carcinomas appear slightly inhomogeneous on both T1- and T2-weighted images. Neither fibrous septa nor lobulated internal architecture can be detected in any thymic carcinoma. If MRI is performed on a patient with anterior mediastinal tumors, thymic carcinoma may be precisely diagnosed when characteristic MR findings are demonstrated.

[Brain CT and MRI findings in fat embolism syndrome]

To elucidate brain CT and MRI findings in fat embolism syndrome (FES), we retrospectively analyzed images from 5 patients with FES during the acute and subacute stages. Brain CT examinations demonstrated brain edema in 2 patients and transient spotty low density lesions in 2 patients. Three patients showed no abnormalities. Brain MRI, however, showed brain abnormalities in all patients during the acute stages. These were revealed as spotty high signal intensity lesions on T2WI, and some showed low intensity on T1WI. These spotty lesions were considered to reflect edematous fluid occurring as a result of the unique pathophysiological condition of FES. While the spotty high signal intensity lesions on T2WI were distributed in the cerebrum, cerebellum, brain stem, thalamus, basal ganglia, internal capsule and corpus callosum, cerebral and cerebellar spotty lesions were characteristically located along the boundary zones of the major vascular territories. This characteristic location might be induced by a hypoxic brain condition in FES because the numerous fat globules present in this condition can block entire brain capillaries. This characteristic signal location on T2WI is a useful indicator for differentiating FES from the primary intra-axial brain injury in patients with multifocal trauma.

[Stage IIIa endometrial carcinoma: MR findings]

[PURPOSE]: An attempt was made to evaluate the ability of magnetic resonance (MR) imaging to diagnose stage IIIa endometrial carcinoma. [MATERIALS AND METHODS]: Thirty-three patients with endometrial carcinoma underwent MR imaging and surgery. Surgical staging was classified as I in 21 patients, II in 3 patients and III in 9 patients. The MR images of each patient were retrospectively reviewed by three radiologists. Only the clinical diagnosis of endometrial carcinoma was previously notified. Segmental disruption of the full thickness of the myometrium was considered serosal invasion. Intraperitoneal metastasis was diagnosed according to three criteria (intraperitoneal solid mass of isointensity compared with endometrial lesion, cystic mass excluding benign ovarian cysts, ascites). These evaluations were compared with the surgical findings and analyzed by the kappa statistic. [RESULTS]: The rates of sensitivity and positive predictive value (PPV) for serosal invasion were 33% and 6%, respectively. False positive evaluation frequently occurred when thickness of the intact myometrium was less than 5mm. The rates of sensitivity and PPV for intraperitoneal metastasis were 86% and 72%, respectively. The reason for false negative evaluation was small foci of intraperitoneal metastasis. Overall, sensitivity and PPV for stage IIIa were 86% and 69%, respectively. [CONCLUSION]: MRI was useful in detecting intraperitoneal metastasis of endometrial carcinoma with the exception of diagnosing serosal invasion. It is difficult to detect small foci of peritoneal metastasis. It is necessary to differentiate adnexal metastasis from benign adnexal masses.

[CT findings of primary retroperitoneal cystic tumors: special emphasis on the distinction benignancy from malignancy]

We describe the CT findings of primary retroperitoneal cystic tumors in 20 patients (cystic lymphangioma, 9; cystic teratoma, 3; cystic neurinoma, 4; mucinous cystadenocarcinoma, 3; synovial sarcoma, 1). CT findings were retrospectively reviewed and the findings correlated with the pathological findings to determine malignant or benign cystic tumors. Definite criteria for malignancy were invasion to surrounding organ and the presence of distant metastasis. However, the sensitivity of these criteria was very low (25%). Enhancement of an intracystic solid component was a reliable criterion (p < 0.05) for malignancy (sensitivity 75%, specificity 81%, accuracy 80%). Either unilocular cystic appearance or the presence of a "neck" (between the cystic mass and paraaortic region) strongly suggested the possibility of benignancy (specificity 100%). The "neck" was thought to be morphologically specific for cystic lymphangioma.

CT and MR findings in tuberculous mediastinitis

OBJECTIVE

Tuberculous mediastinitis, a rare complication of pulmonary tuberculosis, may simulate a mediastinal tumor on chest radiography. For evaluation and follow-up of the disease, CT and MRI are needed.

MATERIALS AND METHODS

Two cases of tuberculous mediastinitis are presented with emphasis on the importance of MRI. In both cases, MRI was performed because the CT appearance was unusual for a mediastinal tumor.

RESULTS

The areas of low signal intensity within the anterior mediastinal mass on both T1- and T2-weighted imaging were due to the reactive fibrous tissue and were suggestive of an inflammatory mass.

CONCLUSION

When a mediastinal mass would be unusual on CT, MRI should be performed. If there are areas of low signal intensity within the mass on both T1- and T2-weighted imaging, an inflammatory mass such as tuberculous mediastinitis, is one of the possibilities.

Small cell carcinoma of the prostate: CT and MRI findings

We report two cases of small cell carcinoma of the prostate and describe the CT and MRI findings, which were primarily based on the rapid growth and high metastatic potential of the tumor. CT and MRI are extremely useful for demonstration of metastatic lesions. Histological confirmation is needed if the findings of CT or MRI are unusual for ordinary adenocarcinoma of the prostate.

[US and CT findings of mucinous carcinomas of the gallbladder]

Mucinous carcinomas of the gallbladder are relatively uncommon. Their radiological findings have not been described previously. We describe the CT and US findings of mucinous carcinoma of the gallbladder in 3 cases. Tumors (thickened wall and/or intraluminal polypoid mass) showed hyperechogeneity or isoechogeneity on US and water density on CT. US clearly detected large polypoid lesions, but CT was unable to detect these lesions in 2 cases. Therefore, we stressed the discrepancy between the findings of US and CT. These features can be explained by the fact that a tumor containing a large amount of mucin produces a mass of near-water density in the gallbladder on CT. It is of value to know the radiological findings of these tumors because the diagnosis is easily missed by CT study alone.

Bronchioloalveolar adenoma of the lung: CT-pathologic correlation

PURPOSE

To correlate the appearance of bronchioloalveolar adenoma (BAA) of the lung at computed tomography (CT) with its pathologic features.

MATERIALS AND METHODS

Nine small pulmonary nodules with ground-glass attenuation were found at CT in 668 patients with lung carcinoma. Seven of these nine lesions were histopathologically diagnosed as BAA in four patients (three men and one woman, aged 66-77 years) (three lesions in one man, two lesions in the woman, and one lesion each in the remaining two men) and are the subject of this study.

RESULTS

BAA of the lung appeared at CT as a small pulmonary nodule with ground-glass attenuation; microscopic examination revealed hyperplasia of the alveolar cuboidal cells on hyperplastic alveolar septa. The CT findings depicted partial reduction of the alveolar air spaces owing to an increase in cellular components within the lesion. Adenocarcinoma cells were also seen within the BAA lesion in one patient.

CONCLUSION

In a patient with known lung carcinoma, a small nodule with ground-glass attenuation simulating a focal lesion of pulmonary interstitial disease must be investigated to rule out BAA or multicentric adenocarcinoma.

[CT findings of sinonasal and orbital Wegener's granulomatosis]

We reviewed the CT findings of four cases of Wegener's granulomatosis that presented as inflammatory masses in the sinonasal cavity or orbit. In the present study, an infiltrative nature and homogeneous texture with contrast enhancement were typical of the masses. In addition, the masses were frequently accompanied by infiltration of the pterygopalatine fossa or destruction of adjacent bone. However, no pathognomonic findings were observed.

[CT findings of pulmonary inflammatory pseudotumors (plasma cell granulomas)]

Pulmonary inflammatory pseudotumor (plasma cell granuloma) is not a true neoplastic lesion, but is composed of a variety of inflammatory cells, predominantly plasma cells. The chest X-ray features resemble those of malignant lung tumors; therefore, CT is often necessary for further evaluation. We report the CT features of five cases with histologically proved pulmonary inflammatory pseudotumor, which can be summarized as follows: a solitary round or oval parenchymal mass with regular or irregular margin, and with or without calcifications. The calcifications are useful for differential diagnosis if present, but they are usually non-specific in shape and configuration. The mean CT attenuation value of the major portion of the mass was increased from 41 HU to 78 HU by the injection of contrast material. In one case, a linear extension of the lesion was seen from the mass to the lung hilum. In three cases, satellite lung nodules were seen. One of these nodules was also proved histopathologically to be inflammatory pseudotumor. The biopsy specimens obtained by using a 20 gauge cutting-needle and an automated biopsy gun were satisfactory for histopathological diagnosis.

[CT and MR imaging of desmoid tumors--comparison of two modalities]

As desmoid tumors invade locally and postoperative recurrence is common, accurate diagnosis of the extent of the tumor is needed prior to surgery. CT and/or MRI evaluation of tumor extension was retrospectively studied in eight patients with desmoid tumors, and the results were correlated with the histopathological findings. All tumors were completely resected even in patients who were evaluated by CT alone. However, the delineation of tumor and local invasion were not clearly demonstrated by CT. On the other hand, the delineation of tumor and local invasion were well visualized on MRI. The MRI picture of desmoid tumors was mainly composed of two different areas of signal intensity. The area of hypointensity in both T 1- and T 2-weighted images was found to have abundant collagen fibers, while the area of isointensity or slight hyperintensity in T 1-weighted images and hyperintensity in T 2-weighted images was found to have fibroblasts. In conclusion, MRI is better suited to the evaluation of patients with desmoid tumors than CT.

[A case of alcoholic liver cirrhosis associated with portal vein thrombosis which was successfully treated by TIPS]

We reported a case of 51-year-old man with repeated bleeding from gastroesophageal varices and portal vein thrombosis which were successfully treated by transjugular intrahepatic portosystemic shunt (TIPS) and thrombolysis. We used a flexible tip puncture needle (.038") which was thought to be safer than Colapinto needle (16G).

[CT features of chronic maxillary osteomyelitis in adults]

CT findings were reviewed in four adult patients with chronic maxillary osteomyelitis (CMO) that was histologically proved. The CT features of CMO included bone destruction and soft tissue mass, predominantly in the inferior portion of the maxillary antrum (all 4 cases), thickening of the antral wall (3 cases) and abnormal soft tissue around the antrum associated with or without bony wall destruction (3 cases). CMO could not be distinguished from cancer of the maxillary antrum on CT because of the similar findings. However, abnormal soft tissue around the antrum together with an undestructed bony antral wall may be useful for differentiating the two diseases.

[CT-guided percutaneous lung biopsy using a cutting needle and an automated biopsy gun. Comparison with lung biopsy using a manual aspiration needle]

Twenty-five percutaneous lung biopsies using a 20-gauge cutting needle and automated biopsy gun (ABG) were performed under CT guidance in 25 patients with thoracic lesions. This procedure was compared with that using a 21-gauge manual aspiration needle in 36 patients (40 examinations, 37 lesions) in terms of success rate, rate of correct diagnosis, mean examination time and rate of complications. Specimens obtained from lung biopsy were graded by a histopathologist according to quality and quantity from 0 to 4 (pathological score). There were no statistically significant differences between the two procedures in terms of success rate, rate of correct diagnosis and rate of complications; only the time required was significantly different. However, sufficient biopsy material and a mean pathological score of G-II 2.8 (that of G-I was 1.9, p less than 0.05) could be obtained by the biopsy procedure using the cutting needle. The above results indicated that aspiration needle biopsy was adequate for lung biopsy, but that a cutting needle and ABG should be used when a good biopsy specimen is needed for tissue diagnosis.

[CT findings of mucin-producing pancreatic cancer--differentiation from chronic pancreatitis]

Mucin-producing pancreatic cancers (MPPC), which include mucinous adenocarcinoma, papillary adenocarcinoma and cystadenocarcinoma, are radiographically characterized by diffuse or localized dilatation of the main pancreatic duct due to excessive mucin production. Therefore, MPPC are occasionally difficult to distinguish from chronic pancreatitis on CT unless the primary pancreatic lesion is visualized. We compared five cases of MPPC with five cases of chronic pancreatitis with marked duct dilatation to determine differences in CT images between the two diseases. There was no significant difference between the two diseases in the nature of duct dilatation (size, extent, contour) or parenchymal changes (atrophy, enlargement, calcification, cystic lesion). However, dilatation of the intramural duct was characteristically observed in MPPC but not in chronic pancreatitis. Papillary masses in the pancreatic duct, when observed, were another finding specific to MPPC.

Bilateral multiple renal adenocarcinomas in a patient with acquired renal cystic disease: correlation of imaging with pathological study

The findings of computed tomography (CT), magnetic resonance imaging (MRI), and angiography were correlated with the histopathological findings in a patient with acquired renal cystic disease (ARCD) and bilateral multiple renal adenocarcinomas. Hemodialysis patients, especially with ARCD, should have a follow-up imaging study for an early detection of renal adenocarcinomas because multiple renal adenocarcinomas would arise frequently and simultaneously from ARCD.

[CT of abdominal aortic aneurysms--aneurysmal size and thickness of intra-aneurysmal thrombus as risk factors of rupture]

In order to seek for the factors to suggest a risk of rupture of abdominal aortic aneurysms (AAA), we measured the largest diameter of AAA and the thickness of intra-luminal thrombus on CT in 72 patients. The mean aneurysmal size was 64 mm in diameter in 9 patients with ruptured aneurysm and 61 mm in diameter in 63 patients with non-ruptured aneurysm respectively (p less than 0.90). The rupture of AAA was seen in 3 of 30 patients with AAA of the small size (less than 50 mm in diameter), in 3 of 16 patients with AAA of the intermediate size (51-66 mm in diameter) and in 3 of 26 patients with AAA of the large size (more than 70 mm in diameter), respectively. The mean intra-luminal thrombus was 9 mm in 9 patients with ruptured aneurysm and 19 mm in thickness in 63 patients with non-ruptured aneurysm respectively (p = 0.05). We concluded from the above results that the aneurysmal size was not important, but the thickness of intra-luminal thrombus was useful for suggestion of a risk of rupture of AAA.

Evaluation of acute renal failure with magnetic resonance imaging using gradient-echo and Gd-DTPA

Detection of acute renal failure (ARF) using fast-scan magnetic resonance imaging (MRI) with Gd-DTPA was studied in a dog model. ARF was produced in five dogs by infusion of norepinephrine (0.75 micrograms/kg/min) into the renal arteries for 40 minutes. MRI was performed 1 hour later and compared with baseline (pre-ARF) MRI. There was no significant difference in the ratios of signal intensity-vs.-time curves from 0 to 35 seconds after injection of Gd-DTPA. However, a difference between the outer and inner medulla was significant in the time period of 5 to 20 minutes after Gd-DTPA injection. These later signal intensity differences by fast-scan (gradient-echo) technique may be useful in the evaluation of ARF.

A renal cell carcinoma extending into the renal pelvis simulating transitional cell carcinoma

A case of renal cell carcinoma with unusual extension is reported, in which the radiographic findings have a close resemblance to those of transitional cell carcinoma of the renal pelvis. We emphasize that it is occasionally difficult to draw a distinction between transitional cell carcinoma with renal invasion and renal cell carcinoma with renal pelvic extension even by computed tomography (CT) and angiography.

[New oral contrast material for gastrointestinal MR examination--green tea mixed with sodium alginate]

We found incidentally the stomach filled with the material of high signal intensity on T1 weighted images. The material was a mixture of green tea and sodium alginate (drug for peptic ulcer). We proved that T1 and T2 were significantly shortened by the mixture in the experimental study. This was successfully used for the patients.

Radiographic findings and hypotensive reactions in excretory urography

The radiographic findings and the hypotension patterns were reviewed in 19 patients having hypotensive reactions in routine excretory urography using ionic contrast medium. The lowest systolic blood pressure was above 80 mmHg in 10 patients while below 80 mmHg in remaining 9 patients. The urogram was unremarkable as long as the systolic blood pressure was preserved above 80 mmHg. In 2 patients, whose systolic blood pressure decreased quickly beyond 80 mmHg immediately after injection of contrast medium, the pyelogram was faint or non-visualized. On the other hand, in 4 patients, whose systolic blood pressure decreased beyond 80 mmHg in several minutes after injection of contrast medium and remained under 80 mmHg for more than 20 minutes, the nephrogram was dense and the pyelogram was faint or non-visualized. Although systolic blood pressure decreased beyond 80 mmHg, the urogram was unremarkable in 3 patients. This was due to the delayed hypotension or the short duration of hypotension.

Non-seminomatous testicular tumors: effect of lesion side on CT detection of lymph node metastasis

Abdominal CT examinations of 40 patients with non-seminomatous testicular tumors were reviewed with previous knowledge of the side of the testicular primary. Metastatic nodes, between 1.5 cm and 2.0 cm in diameter were overlooked more frequently in patients with right than in those with left testicular primaries, because mildly enlarged aorto-caval or para-caval nodes (which are the most frequent site of metastasis from a right testicular lesion) were more difficult to detect than enlarged left para-aortic lymph nodes. Efforts to delineate the aorto-caval region on CT examinations of patients with right-sided lesions must be increased in order to reduce a surprisingly high false negative rate.

Hemiazygos continuation of a left inferior vena cava: CT appearance

The CT appearance of hemiazygos continuation of a left-sided inferior vena cava is presented along with discussion of associated anomalies.

Computed tomography of retroperitoneal cystic lymphangiomas

The CT features of retroperitoneal lymphangiomas are unilocular or multilocular cysts in the retroperitoneum and slightly and uniformly thickened wall that enhances following contrast medium administration. Three cases are reported.

Enzyme immunoassay of blasticidin S with high sensitivity: a new and convenient method for preparation of immunogenic (hapten-protein) conjugates

An antibody against blasticidin S (BLS), an antibiotic effective for blast disease of rice, has been produced in rabbits immunized with a blasticidin S-protein conjugate prepared by a novel and convenient procedure devised to couple BLS to bovine serum albumin (BSA) after sodium borohydride reduction of its disulfide bonds, using N-(m-maleimidobenzoyloxy)succinimide (MBS) as a cross-linker. BLS-MBS-BSA conjugate contained about 16 BLS per BSA molecule. Enzyme labeling of BLS with beta-D-galactosidase was performed by utilizing another cross-linker, N-(gamma-maleimidobutyryloxy)succinimide by means of a convenient labeling method which we introduced last year. A double antibody enzyme immunoassay of BLS which could determine as little as 100 pg per tube of BLS was developed using labeled BLS and anti-BLS antiserum. Various commonly used drugs were found to have little reactivity in this immunoassay, indicating that the anti-BLS produced is highly specific. The titer of the anti-BLS was excellent and 10,000,000-fold diluted solution could bind with the enzyme labeled BLS.