Indirect computed tomography lymphography of subdiaphragmatic lymph nodes using iodinated nanoparticles in normal dogs

RATIONALE AND OBJECTIVES: We evaluated the imaging characteristics of an iodinated particulate contrast agent for indirect computed tomography (CT) lymphography of normal subdiaphragmatic lymph nodes in dogs. METHODS: Four milliliters of a 15% (wt/vol) iodinated nanoparticle suspension was injected into the gastric, colonic, rectal, or cervical submucosa, loose paraprostatic fascia, or metatarsal subcutaneous tissues in 10 healthy beagles. Endoscopic, CT, or ultrasound guidance was used when necessary to facilitate contrast agent delivery. CT and radiographic images were obtained prior to contrast administration and at 4 hr, 24 hr, and 7 days postcontrast injection. Postmortem examinations were then conducted. RESULTS: CT images showed enhancement of regional lymph nodes draining the various injection sites. The mean attenuation of opacified nodes was 678 +/- 463 Hounsfield units 24 hr after injection and remained elevated 7 days later. Lymph node opacification on CT images correlated well with the node location observed on postmortem examinations. CONCLUSION: Subdiaphragmatic lymph nodes can be effectively opacified using an iodinated nanoparticle contrast agent for indirect CT lymphography.     

Characterization of reactive versus tumor-bearing lymph nodes with interstitial magnetic resonance lymphography in an animal model

RATIONALE AND OBJECTIVES: To determine if magnetic resonance lymphography performed with subcutaneously administered AMI-227, a nanoparticulate iron oxide contrast agent, can distinguish reactive from tumor-bearing lymph nodes. MATERIALS AND METHODS: Mature male Copenhagen rats were inoculated with cell suspensions of R3327-MAT-LyLu rat prostate carcinoma (n = 21) or Freund's complete adjuvant (n = 15) in the left footpad to generate ipsilateral popliteal lymph node metastases or lymphadenitis. At 12 to 14 days after inoculation, T1-and T2-weighted magnetic resonance images of bilateral popliteal areas were obtained before and 24 hours after subcutaneous administration of AMI-227. Contrast-to-noise ratios were calculated in precontrast and postcontrast images. Bilateral popliteal nodes were excised for pathologic assessment. RESULTS: AMI-227 resulted in decreased contrast-to-noise ratios in reactive (T1-W = -7.01 +/- 1.13, T2- W = -31.64 +/- 5.35) and normal (T1 - W = -13.56 +/- 1.97, T2 - W = -21.62 +/- 2.51) nodes. Contrast-to-noise ratios were unchanged (T1 - W = -0.22 +/- 1.71, T2 - W = -2.20 +/- 4.19) in tumor-containing nodes. These differences in contrast-to-noise ratio changes between tumor-bearing versus nontumor-bearing nodes were statistically significant (P < 0.05). Histologic analysis showed similar distribution of AMI-227 within normal and reactive nodes, but not in tumor-bearing nodes. CONCLUSIONS: Differences in AMI-227-uptake between tumor- and nontumor-bearing nodes detected with magnetic resonance imaging are helpful for distinguishing the two entities.     

Variability in the detection of enlarged mediastinal lymph nodes in staging lung cancer: a comparison of contrast-enhanced and unenhanced CT

OBJECTIVE: Because CT protocols for staging lung cancer vary and little information exists regarding the diagnostic importance of using i.v. contrast material, our intent was to evaluate intra- and interobserver agreement in the detection of enlarged mediastinal lymph nodes, comparing i.v. contrast-enhanced and unenhanced CT. SUBJECTS AND METHODS: Fifty patients with known or suspected bronchogenic carcinoma underwent unenhanced thoracic CT followed by contrast-enhanced CT. Three observers noted enlarged lymph nodes (> 10 mm in the short axis) and assigned the enlarged nodes to American Thoracic Society nodal station designations. Enlarged lymph nodes were grouped two ways: by assigning the exact number of enlarged lymph nodes found (zero, one, two, three, four or more), and by assigning whether at least one, or no, enlarged mediastinal lymph nodes were found at a station ("one or none"). Agreement levels were determined for inter- and intraobserver interpretations using weighted kappa statistics and the McNemar test. RESULTS: The number of enlarged lymph nodes with enhanced CT was 11% higher than on unenhanced studies (418 versus 377; p = .044). Numbers of enlarged lymph nodes were different for five stations; however, the numbers were small except for the right upper paratracheal station (2R) (contrast-enhanced, 68 enlarged lymph nodes; unenhanced, 44 enlarged lymph nodes; p = .014). With regard to all stations together, intraobserver agreement between contrast-enhanced and unenhanced studies was almost perfect (kappa range, .85-.94), and no difference was found for any observer in the proportion of patients with at least one enlarged lymph node. Interobserver agreement was substantial or almost perfect for the total number of enlarged lymph nodes. For specific stations, the lowest kappa value was .48 at 2R. One observer reported more patients with at least one enlarged lymph node with contrast enhancement at station 2R (p = .031). Greater agreement existed between two observers at station 2R with contrast enhancement versus no enhancement (kappa = .85 versus .48; p = .02). Conclusions matched, and calculations of estimated kappa values gave similar results for determination of the specific number of enlarged lymph nodes at a station and the "one or none" category. CONCLUSION: We found high agreement for intra- and interobserver interpretations for contrast-enhanced and unenhanced CT, although contrast-enhanced CT revealed more enlarged lymph nodes, especially at station 2R.     

CT-angiography as a non-invasive method for the evaluation of the patency of TIPSS (transjugular intrahepatic portasystemic shunt)

PURPOSE: To evaluate the feasibility of determining patency of the transjugular intrahepatic portosystemic shunt (TIPSS) by non-invasive CT angiography (CTA). MATERIALS AND METHODS: (1) Non-enhanced scanning of the shunt. (2) Bolus tracking by injecting 20 ml of non-ionic contrast material through a cubital vein access to determine the time to maximal shunt enhancement. (3) Contrast-enhanced spiral CT study applying a delay according to the time to peak of the shunt, 3 mm collimation, 5 mm table feed and 3 mm reconstruction interval. (4) 3D and multiplanar reconstructions. (5) Evaluation of the questions: intrahepatic shunt patent or not; evidence of intimal hyperplasia; evidence of stenosis and potential location. (6) Transjugular portography via the stent. (7) Comparison of angiographic findings and CT morphology. RESULTS: Eight patients had inconspicuous CTA. Four of them had a normal shunt at angiography, four had slight intimal hyperplasia. No intervention was necessary in these patients. CTA of three patients showed intimal hyperplasia (lumen reduction between 10% and 50%). The diagnosis was angiographically confirmed in all cases. Due to a high portosystemic gradient intervention was required in all. In five patients CTA and angiography showed a stenosis (reduction of shunt lumen > 50%). All required a revision including stent placement or PTA of the shunt tract. Four shunts were occluded; all occlusions were shown both in CTA and angiography. CONCLUSIONS: None of the shunts with normal findings at CTA required revision. All shunts conspicuous on CTA resulted in revision. In this study, CTA turned out to be an accurate, non-invasive method to evaluate the patency of TIPSS.     

Mediastinal tuberculous lymphadenitis: CT findings of active and inactive disease

OBJECTIVE: The purpose of this study was to analyze CT findings of active and inactive disease in patients with mediastinal tuberculous lymphadenitis. MATERIALS AND METHODS: Using biopsy and culture results, we categorized 49 consecutive patients with mediastinal tuberculous lymphadenitis studied with CT scans as patients with active disease (n = 37) or patients with inactive disease (n = 12). Follow-up CT scans were obtained after antituberculous therapy in 25 patients with active disease and three patients with inactive disease. In 10 patients (seven with active disease and three with inactive disease), CT findings were analyzed and correlated with pathologic findings. RESULTS: In all 37 patients with active disease, the nodes (n = 151) varied in size (1.5-6.7 cm; mean, 2.8 +/- 1.0 cm) and had central low attenuation and peripheral rim enhancement. Calcifications within the nodes were seen in seven patients (19%). In the 12 patients with inactive disease, the nodes (n = 34) varied in size (1.0-4.7 cm; mean, 2.1 +/- 1.0 cm) but were usually smaller than nodes in patients with active disease. In the patients with inactive disease, the diseased nodes were homogeneous and without low-attenuation areas. Calcifications within the nodes were seen in 10 (83%) of the 12 patients with inactive disease. Low-attenuation areas within the nodes corresponded pathologically to areas of caseation necrosis in seven patients with active disease and in no patients with inactive disease. After treatment, enlarged mediastinal nodes in patients with active disease shrunk and low-attenuation areas within the nodes disappeared in all 25 patients. However, the findings of calcified nodes in the three patients with inactive disease did not change after 6 months of follow-up. CONCLUSION: In these 49 patients with mediastinal tuberculous lymphadenitis, CT findings of nodes with central low attenuation and peripheral rim enhancement suggested active disease, and findings of homogeneous and calcified nodes suggested inactive disease. Low-attenuation areas within the nodes had pathologic correspondence to areas of caseation necrosis and may be a reliable indicator for disease activity.     

Computed tomography, ultrasound and lymphography in the diagnosis of malignant lymphoma

Lymphographic findings were compared with the results at histopathology in 42 laparotomized patients with malignant lymphoma. Of 12 patients with lymphographically suggested lesions in normal-sized lymph nodes, only one had pathologic changes at histologic examination. Computed tomography gave a better idea of the extent of the disease than lymphography. Moreover, CT had an equal diagnostic accuracy as lymphography for demonstrating enlarged para-aortic lymph nodes. CT should therefore be able to replace lymphography in examination of malignant lymphoma. Ultrasound had the same diagnostic accuracy as CT regarding the upper and middle abdomen but not in the lower abdomen. Ultrasound is of special value in thin patients and when guided needle biopsy is required.     

US case of the day. Diffuse large B-cell lymphoma (posttransplant lymphoproliferative disorder [PTLD])

OBJECTIVE: We describe two new CT findings of congestive heart failure (CHF): enlarged mediastinal lymph nodes and hazy heterogeneous mediastinal fat. MATERIALS AND METHODS: Forty-six patients were retrospectively identified who had major and minor clinical signs of congestive heart failure and had undergone chest CT during their symptomatic period. Two radiologists reviewed the CT studies and by consensus documented the presence or absence of imaging findings of CHF, including interstitial abnormalities, vascular redistribution, axial thickening, pleural effusions, cardiac enlargement, and mediastinal abnormalities. RESULTS: Smooth septal thickening, bilateral pleural effusions, vascular redistribution, and cardiac enlargement were the most common CT findings in patients with CHF. Enlarged mediastinal lymph nodes and hazy mediastinal fat were seen in 55% and 33% of cases, respectively. In a cohort of 17 patients with elevated pressures in the pulmonary capillary wedge documented within 24 hr of CT, CT scans revealed lymphadenopathy in 14 patients (82%) and inhomogeneous fat in 10 patients (59%). CONCLUSION: Enlarged mediastinal lymph nodes and hazy mediastinal fat occur in patients with CHF and are revealed by CT. Lymphadenopathy in patients with CHF does not necessarily indicate malignancy or an infectious process.     

Antistaphylococcal and antistreptococcal killing kinetics of ciprofloxacin, ofloxacin, sparfloxacin, and trovafloxacin

BACKGROUND: Use of blood culture studies for early diagnosis of Mycobacterium avium complex (MAC) infection has become important due to the recent development of effective antibiotic therapy for this condition. This study assessed the abdominal computed tomography (CT) findings in patients with AIDS who presented with bacteraemic MAC infection. METHODS: A retrospective analysis of abdominal CT scans was performed in 24 patients who presented with MAC-positive blood culture. CT images were reviewed specifically to evaluate for lymph node enlargement and attenuation, hepatomegaly, splenomegaly, bowel wall abnormality and for any other pathological changes. Comparison was made to prior reports of the CT findings in this disease process. RESULT: Enlarged intra-abdominal mesenteric and/or retroperitoneal lymph nodes were found in 10 patients (42%). These nodes were characterized by homogeneous, soft-tissue attenuation in eight of the 10 patients. Hepatomegaly, splenomegaly and small bowel wall thickening were noted in 12 (50%), 11 (46%) and four (14%) patients, respectively. CT findings were evaluated as normal in six (25%) patients. CONCLUSIONS: Enlarged mesenteric and/or retroperitoneal lymph nodes in AIDS patients with bacteraemic MAC were observed much less frequently on CT than previously reported in AIDS patient populations. Normal abdominal CT findings do not exclude this diagnosis and may reflect a trend towards earlier detection of MAC disease.     

Effects of microwave tissue coagulation on the livers of normal rabbits: a comparison of findings of image analysis and histopathological examination

The livers of normal rabbits were subjected to microwave tissue coagulation (MTC), and comparison was made of the subsequent time-course changes in tissue observed on MRI, CT and histopathological examination. 16 rabbits were used. MTC was performed with a 21 gauge needle electrode inserted into the liver at laparotomy. 1-2 h after thermal coagulation, a region with slightly lower attenuation than that of surrounding normal liver parenchyma was observed on CT, and no enhancement was detected. With MRI, change from high signal intensity to iso-signal intensity from the inner zone to the margin was found on T1 weighted images (T1WI), and heterogeneous high signal intensity was observed on T2 weighted images (T2WI). On Gd-DTPA enhanced MRI, no enhancement occurred. 1-4 weeks after coagulation, the cellular structure at the site of coagulation was lost on histological examination, and the tissue became necrotic. On CT, homogeneous water density was observed, and no enhancement was detected. With MRI, regions of iso- or slightly low signal intensity were observed on T1WI, and regions of heterogeneous high to low signal intensity were seen on T2WI. After 1 week, a granulation layer consisting mainly of fibrous tissue developed, and a ring-shaped enhancement was observed in the low signal intensity region on T1WI and in the high signal intensity region on T2WI. The ring-shaped enhancement was also noted on CT. MRI appears to be useful for observation of time-course changes following MTC therapy because of its sensitivity in the detection of tissue changes.     

Enhancement of computed tomography liver contrast using iomeprol-containing liposomes and detection of small liver tumors in rats

RATIONALE AND OBJECTIVES: We evaluated iomeprol-containing liposomes (Lipiom), a new contrast medium for computed tomography (CT) liver scanning, in an animal model of chemically induced hepatocellular carcinomas and other liver tumors in rats. METHODS: Liver tumors were induced by administration of carcinogens to rats, either 0.55% (w/w) 1'-hydroxysafrole in the diet or induction by 3'-methyl-4-diethylaminoazobenzene followed by promotion with carbon tetrachloride. CT scanning was performed 1-3 hr after intravenous injection of iomeprol-containing liposomes. RESULTS: After injection of iomeprol-containing liposomes at a dose of 70 mg of liposome-entrapped iodine per kilogram of body weight, the normal liver parenchyma showed a contrast enhancement, in Hounsfield units, of more than 60% over the control value before bolus. Liver tumors with no or few Kupffer cells were not enhanced and appeared as dark areas within the normal parenchyma. Tumors and pretumoral lesions devoid of Kupffer cells, as small as 3 mm in diameter, could be distinguished using this non-invasive method. CONCLUSION: CT liver scanning after injection of iomeprol-containing liposomes appears to be promising method for detecting liver tumors and focal liver lesions.     

Lymphography in patients with suspected malignancy or fever of unexplained origin

Forty-four patients underwent bipedal lymphography for evaluation of fever of unexplained origin, or because a malignant tumor (usually lymphoma) was suspected clinically. Extensive prior medical evaluation was inconclusive. The lymphograms were of no apparent value in detecting the etiology of the illness. Reactive follicular hyperplasia was frequently seen and sometimes simulated lymphoma on the lymphogram. The primary value of lymphography in such cases is as an aid in planning biopsy and surgery.     

Hepatic imaging with iodinated nanoparticles: a comparison with iohexol in rabbits

RATIONALE AND OBJECTIVES: We evaluated the efficacy of a particulate computed tomography (CT) contrast agent in an animal model of focal liver disease. METHODS: Ethyl ester of diatrizoic acid (EEDA) is an iodinated (89 mg I/ml) nanoparticulate (200 nm) contrast agent intended for intravenous use that is currently undergoing preclinical testing in our laboratory. Focal liver abscesses were created in 11 New Zealand White rabbits. Iohexol and EEDA were administered to each animal on different days. CT scanning was performed at intervals following contrast agent administration. Liver and abscess enhancement were measured and compared. Dynamic imaging experiments in normal animals were also performed using both agents. RESULTS: EEDA resulted in significantly greater enhancement of the liver and liver-to-abscess contrast than did iohexol at all time points beyond 5 min at approximately 25% of the total iodine load. During dynamic imaging, liver and aortic enhancement were greater with EEDA than with iohexol, except during a 20- to 40-sec period immediately following contrast agent administration. CONCLUSION: EEDA is superior to iohexol for imaging liver abscesses. Our results suggest that liver-directed agents such as EEDA may prove to be more efficacious than currently available extracellular agents designed for liver CT scanning.     

Small lymph nodes of the abdomen, pelvis, and retroperitoneum: usefulness of sonographically guided biopsy

PURPOSE: To evaluate the usefulness of sonographically guided percutaneous biopsy of small lymph nodes in the abdomen, retroperitoneum, and pelvis. MATERIALS AND METHODS: From May 1995 through January 1997, 35 sonographically guided lymph node biopsies were performed in 34 patients. All biopsies were performed with a 20- (n = 18) or 22-gauge (n = 10) self-aspirating needle alone or in combination (n = 7). To determine the amount of compression achieved with the transducer, the skin-to-lesion distance on reference computed tomographic (CT) scans was compared with that on sonograms. A biopsy was considered successful if a specific benign or malignant diagnosis was rendered by the pathologist. RESULTS: Of 35 sonographically guided biopsies, 30 (86%) were successful. Diagnoses included 26 (74%) cases of carcinoma, three (9%) cases of benign reactive lymphocytosis confirmed at open biopsy, and one (3%) case of a lymph node with a positive acid-fast bacilli stain. The average lymph node diameter was 2.1 cm (range, 0.9-4.3 cm). With sonography, a mean of 2.5 needle passes (range, 1-5) were made per biopsy. Transducer compression reduced the skin-to-lesion distance from an average of 8.8 cm (at CT) to 4.5 cm. CONCLUSION: Sonographic guidance seems to provide a reasonable alternative to CT in biopsy of small abdominal, pelvic and retroperitoneal lymph nodes.     

Distribution and contrast enhanced CT appearance of abdominal tuberculous lymphadenopathy

PURPOSE: To clarify the contrast enhanced CT features and anatomic distribution of the disseminated vs non-disseminated tuberculosis (TB) involving abdominal lymph nodes. MATERIALS AND METHODS: The contrast enhanced CT findings of abdominal lymphadenopathy in 25 patients, including disseminated TB associated with miliary TB of the lung (n = 5) and non-disseminated TB (n = 20), were retrospectively evaluated in a blind review to assess our criteria of morphology, density and location of the involved lymphadenopathy. RESULTS: The enhancement patterns of disseminated TB were not different from those of non-disseminated TB. Ninety-six percent of the patients had peripheral rim enhancement, and 60% showed a multilocular appearance. The enlarged lymph nodes of TB were less than 4 cm in diameter. Lymphadenopathy caused by hematogenous dissemination often accompanied splenic involvement showing multiple low-density foci in the spleen. The predominant sites of lymphadenopathy of disseminated TB were hepatoduodenal ligamentous, hepatogastric ligamentous, mesenteric, and both upper and lower portions of the retroperitoneal lymph nodes, whereas non-disseminated TB mainly involved hepatoduodenal ligamentous, hepatogastric ligamentous, mesenteric and upper retroperitoneal lymph nodes, excluding the lower retroperitoneal lymph nodes. By combining contrast enhancement patterns and the anatomic distribution of lymphadenopathy shown on the contrast enhanced CT images, reviewers made a correct diagnoses of tuberculosis in 94%, of cases, with a specificity of 95% and sensitivity of 92%. CONCLUSION: Contrast enhanced CT patterns correlate well with the pathologic features of tuberculous lymphadenopathy. A different anatomic distribution between disseminated and non-disseminated TB involving the lower retropentoneal lymph nodes was recognized in this study.     

The localization of aldosterone-producing adenoma on computed tomography--a comparative study with adrenal scintigraphy and plasma aldosterone concentration in the adrenal or renal vein

The evaluation of computed tomography (CT) for detecting aldosterone-producing adenoma in primary aldosteronism was performed by comparison with adrenal scintiscan; determination of aldosterone in adrenal or renal veins, retroperitoneal pneumography and adrenal venography was reliable for diagnosis of adrenal tumors in pheochromocytoma or Cushing's syndrome, but not so effective for small adenoma of primary aldosteronism. An abdominal CT scan was performed on six patients with primary aldosteronism, one with idiopathic hyperaldosteronism and one with glucocorticoid responsive hyperaldosteronism; in an attempt to evaluate the utility of this noninvasive procedure. Diagnosis of hyperaldosteronism was made by demonstrating the elevated plasma aldosterone concentration and aldosterone secretion rate, normal excretion rate of urinary 17-OHCS and 17-KS, and low plasma renin activity. The CT scan correctly predicted unilateral adrenal adenoma in all the patients with primary aldosteronism of which the findings were identical to those demonstrated by surgery. The diameter of these tumors ranged from 10 X 7 X 6 to 19 X 17 X 14 mm. Also the CT scan in idiopathic hyperaldosteronism and glucocorticoid responsive hyperaldosteronism showed bilateral adrenal hyperplasia and bilateral normal adrenal glands, respectively. The pathological findings in these two cases disclosed the adrenal hyperplasia of zona glomerulosa and adrenal hyperplasia of zona subglomerulosa accompanied by a normal thickness of the adrenal gland, respectively. The precision of the CT scan, adrenal scintigraphy and determination of plasma aldosterone in the adrenal or renal veins were almost equal to the diagnosis of the localization of adrenal adenoma. It is concluded that the CT scan is a noninvasive and most useful method for the localization of aldosterone-producing adenoma and helpful in distinguishing adrenal adenoma from adrenal hyperplasia.     

Abdominal CT findings when the superior vena cava, brachiocephalic vein, or subclavian vein is obstructed

OBJECTIVE: We evaluated findings on contrast-enhanced abdominal CT scans that suggest obstruction of the superior vena cava, brachiocephalic vein, or subclavian vein. SUBJECTS AND METHODS: We conducted a retrospective review of 22 patients with superior vena caval, brachiocephalic vein, or subclavian vein obstruction and analyzed the upper abdominal images on a chest CT scan or an abdominal CT scan. We assessed collateral vessels in the upper abdomen to answer the following question: Did enhancement approach undiluted IV contrast or were there other findings? In the second part of our study, we conducted a prospective review of abdominal CT scans of 200 patients without known mediastinal disease or known upper extremity venous occlusion to determine the frequency of abnormal enhancement of these vessels in a healthy population. RESULTS: The groups of collateral vessels revealed on abdominal CT scans were azygos or hemiazygos veins, internal mammary veins, lateral thoracic and superficial thoracoabdominal veins, vertebral venous plexus veins, and small mediastinal collateral veins. In the retrospective series, one patient had focal enhancement of the liver and early inferior vena caval enhancement due to collateral vessels. In the prospective series, abdominal CT scans of two patients (1%) revealed dense undiluted enhancement of one or more groups of collateral vessels: One patient had an ipsilateral pacemaker, and the other patient had an anterior neck phlegmon to the upper mediastinum. Both conditions may have been factors in the revealing of the collateral vessels. Two other patients (1%) in the prospective series had mild to moderate vessel enhancement that was less than that from undiluted contrast material. In one of these patients, the enhancement was related to abdominal wall hyperemia after surgery. In the other patient, enhancement may have been the result of ipsilateral axillary nodes. CONCLUSION: On upper abdominal CT scans, dense undiluted contrast material in the collateral vessel groups that we studied suggests possible obstruction of the superior vena cava, brachiocephalic vein, or subclavian vein.     

Dynamics of myocardial contrast enhancement: an in vivo computed-tomographic study

Enhancement of normal functioning myocardium was quantitated in 15 dogs by serial computed transmission tomographic (CT) images during the bolus (10 ml/sec.) or slow (1 ml/sec.) intravenous injection of diatrizoate contrast media (1 ml/kg body weight) in concentrations of 37, 18.5, or 9.25 g iodine (I)/dl. Homogenous images of myocardial enhancement were obtained. However, major streak artifacts were observed frequently when contrast material was injected as a bolus, and myocardial edges were not defined clearly when contrast material with a concentration of 9.25 g I/dl was injected slowly. Time-attenuation curves of normal myocardial enhancement constructed from serial CT images demonstrated a peak in contrast enhancement (delta Hounsfield units, 22-45) followed by a period of deterioration that lasted two to three minutes. These results can be applied to make optimal use of both single (static) and serial (dynamic) myocardial CT images.     

胰腺实性假乳头状瘤的CT征象分析

Objective: The aim of our study was to demonstrate the CT features of solid pseudopapillary tumor of the pancreas (SPTP) so as to improve the imaging diagnostic abilities. Methods: The CT materials of 10 cases with surgery andpathology proved SPTP were retrospectively analyzed, including 8 females and 2 males, their age ranged from 12 to 54years (average being 27.2 years). All of the 10 cases underwent spiral CT scan and also with contrast enhancement before surgery. Results: All of the 10 cases were isolated mass. They were located at the head (n = 5), tail (n = 4), and body (n =1) of the pancreas. Their shapes were round (n = 3), oval (n = 4), and irregular (n = 3). The long-axis diameter ranged from 2.1-8.6 cm (mean 6.5 cm). All of neoplasms consisted of solid and cystic components. Mostly solid components in 5 cases,nearly the same proportion of solid and cystic part in 3 cases, and mostly cystic components in 2 cases. After dynamic contrast-enhanced, the solid parts of the lesion showed progressive enhancement and the cystic parts of the lesion showed no enhancement. Calcification was noted in 5 cases, such as the spot, line-like, small nodules or patchy calcification. Fluiddebris level and "floating cloud" sign were noted in one case. In one case of mostly cystic components, patchy area of high attenuation were shown on CT imaging which then was proved as old hemorrhage by pathologic evaluation. Seven cases were completely encapsulated and made more remarkable on post-contrast images. Three cases had incomplete capsules,and adhesion to the surrounding tissues could be seen during operation, including one case in which invasion to the adjacent adipose tissues near the inferior vena cava and walls of the duodenum could be seen under the microscope. Pancreatic duct broadening or hepatic duct dilatation was caused by tumor each in 1 case. All of the 10 cases had no enlargement of the intra-abdominal lymph nodes or distant organ metastasis. Conclusion: SPTP occurs mainly in young women and has comparatively characteristic CT imaging features: a large solid and cystic tumor of pancreas, sharp edges, the solid parts of the lesion showed progressive enhancement, a few with hemorrhage and calcification.     

Surgical treatment of penile cancer: a follow-up report

One hundred and fifteen patients with penile cancer were treated at Roswell Park Memorial Institute from 1952 to 1975. A full follow-up is reported and factors involving the prognosis are analyzed. Although the clinical error of staging was near 30%, the lymphography results suggest that this study may result in added improvement in preoperative staging. Early diagnosis, adequate surgical resection, and lymph node dissection will improve the survival significantly. When dealing with an individual patient the prognosis is poor when any one or more of the follow factors are present: the lesion involves the shaft; there is a positive margin at the surgical resection; total penectomy is necessary to obtain tumor-free margin; lymphography is positive for tumor involvement of lymph nodes; lymph node dissection has not been performed; positive lymph nodes are found on surgical exploration. The good prognostic factors include: a lesion confined to the glans and partial penectomy is sufficient to obtain a tumor-free margin of resection; no clinical evidence (including lymphography) of lymph node invovlement; performance of lymph node dissection. The histological grading of the tumor should not influence the clinical decision for treatment in our opinion at this time, based on our current results. Further prospective studies of different factors involved in etiology, diagnosis, and treatment of penile cancer are suggested.     

Parotid pleomorphic adenomas: delayed CT enhancement

BACKGROUND AND PURPOSE: Weak or absent CT enhancement in pleomorphic adenomas of the parotid gland has been observed immediately after i.v. contrast administration. This feature can result in poor lesion conspicuity relative to both normal parotid tissue and other parotid abnormalities. The purpose of this study was to document the delayed CT enhancement characteristics of parotid pleomorphic adenomas and to preliminarily compare these results with the enhancement characteristics of other parotid gland tumors. METHODS: Preoperative CT scans from 18 pathologically proved parotid gland neoplasms were reviewed retrospectively. Lesions included eight pleomorphic adenomas, four Warthin's tumors, two squamous cell carcinomas, two mucoepidermoid cancers, one acinic cell carcinoma, and one melanoma metastasis. In all cases, axial CT was performed after the administration of 100 to 150 mL of i.v. contrast material, followed by delayed (average, 24 minutes; range, 13 to 34 minutes) coronal CT scanning. The mean normalized Hounsfield unit (HU) attenuation of each lesion was computed by drawing a region of interest around the entire mass and dividing the resulting HU value by that of the contralateral uninvolved parotid gland. RESULTS: For all eight pleomorphic adenomas, the degree of contrast enhancement increased and became progressively more uniform with time. Mean normalized axial lesion enhancement averaged 1.20 +/- 0.35 at 8 minutes, compared with 2.30 +/- 0.66 on the coronal scans at 24 minutes. For the 10 nonpleomorphic adenomas, no significant change was found in either the degree or pattern of contrast enhancement between the immediate and delayed CT scans. In these tumors, peak enhancement was reached early, during axial scanning. CONCLUSION: Delayed CT contrast enhancement is observed in parotid pleomorphic adenomas, increasing in both degree and homogeneity with time. This feature may be useful in selecting an appropriate contrast delay when scanning possible pleomorphic adenomas to improve lesion conspicuity and, potentially, to better distinguish these tumors from other parotid abnormalities.