Radiologic and anatomic study of the extraperitoneal space associated with the rectum.

OBJECTIVE: The objective of our study was to clarify the anatomic and radiologic features of the extraperitoneal fasciae and fascial spaces associated with the rectum. MATERIALS AND METHODS: Fourteen embalmed cadavers were studied: two for gross anatomy; six for sectional anatomy, of which two underwent histologic study; and six for space perfusion study. These examinations were followed by CT and cross dissection to observe the pelvic extraperitoneal fasciae and the role of the fasciae in the anatomic subdivision and communication of the fascial spaces. Eighty healthy subjects underwent CT or MRI to identify the imaging characteristics of the pelvic fasciae. RESULTS: Cadaver dissection and histologic study revealed a distinct sheath consisting of dense connective tissue encasing the rectum and surrounding adipose tissue like a sleeve that divided the rectal extraperitoneal space into the perirectal space and pararectal space. Perfusion studies showed communication between the pararectal spaces and the vesical extraperitoneal space anteriorly and the anterior pararenal space superiorly, but not with the perirectal space. In healthy subjects, both CT (95.0%) and MRI (97.5%) showed a circular or linear structure representing the rectal fascia outside the rectum encasing the rectum and its surrounding adipose tissue. CONCLUSION: The extraperitoneal segment of the rectum and its surrounding adipose tissue are encased by a fascia, like a sleeve, that can be seen on CT and MRI in healthy populations. The fascia divides the rectal extraperitoneal space into the perirectal space and pararectal space, and it may prevent lesions of the rectum from spreading to other pelvic extraperitoneal spaces.

Addison's disease due to adrenal tuberculosis: MRI features.

BACKGROUND: Findings of adrenal tuberculosis with MR scanning have never been reported in the literature. The aim of this study was to determine MR characteristics for tuberculous Addison's disease, and evaluate the utility of MR imaging as a useful diagnosis tool of the entity. PATIENTS AND METHODS: Eighteen patients with proven adrenal tuberculosis were included. All patients had conventional T(1)- and T(2)-weighted image. Among the 18 patients, contrast-enhanced T(1)WI had been done in 10. MR manifestations were retrospectively evaluated blindly for the location, contour, signal intensity, and enhancement patterns. RESULTS: All patients clinically exhibited hyperpigmentation and lethargy. Physical examination revealed weight loss, signs of dehydration, and hypotension. Biochemical investigation confirmed adrenal insufficiency. The adrenal glands were affected bilaterally in 16 patients (89%) and unilaterally in 2 patients (11%). Thirty-three glands were enlarged (97%), while one was atrophic (3%). Of the 33 enlarged glands, 20 (61%) were mass-like and 13 (39%) had preserved contours. The central region of the enlarged glands demonstrated T(2) hypo- or iso-SI in 21 (62%) and T(2) hyper-SI in 12 (38%). Among the 18 enlarged glands that had contrast MR, 15 (83%) had peripheral rim enhancement, 1 (6%) had homogeneous enhancement, and the last two (11%) had heterogeneous enhancement. CONCLUSION: MR characteristics can reveal certain pathological changes of adrenal tuberculosis, and MR imaging could be recommended as the imaging modality for the diagnosis of the entity.

Uncommon adrenal masses: CT and MRI features with histopathologic correlation.

Adrenal glands are common sites of diseases. With dramatically increased use of computed tomography (CT) and magnetic resonance (MR) imaging, more and more uncommon adrenal masses have been detected incidentally at abdominal examinations performed for other purposes. In this article, uncommon adrenal masses are classified as cystic masses (endothelial cysts, epithelial cysts, parasitic cysts, and pseudocysts), solid masses (ganglioneuroma, ganglioneuroblastoma, extramedullary plasmacytoma (EMP), neurilemmoma, and lymphoma), fat-containing masses (myelolipoma, teratoma), and infectious masses (tuberculoma), and the imaging features of these uncommon masses are demonstrated. Although most of these lesions do not have specific imaging features, some fat-containing masses and cystic lesions present with characteristic appearances, such as myelolipoma, teratoma, and hydatid. Combination with histopathologic characteristic of these uncommon masses of adrenal gland, radiological features of these lesions on CT and MR imaging can be accurately understood with more confidences. Moreover, CT and MRI are highly accurate in localization of uncommon adrenal masses, and useful to guide surgical treatments.

Addison's disease due to adrenal tuberculosis: contrast-enhanced CT features and clinical duration correlation.

PURPOSE: To describe CT morphology of untreated adrenal tuberculosis during the different stages of the natural history of the disease and to evaluate the diagnostic implications of CT features. MATERIALS AND METHODS: We retrospectively evaluated CT features in 42 patients with documented adrenal tuberculosis for the location, size, morphology, and enhancement patterns shown on CT images. The clinical duration were correlated with the CT features. RESULTS: Of the 42 patients with untreated adrenal tuberculosis, bilaterally enlarged adrenal glands were revealed in 38 cases (91%), unilaterally enlarged in 3 cases (7%), and normal size in 1 case (2%). Of the 41 cases (98%) with enlargement, mass-like enlargement was seen in 20 cases (49%) and enlargement with preserved contours in 21 cases (51%). Peripheral rim enhancement presented in 22 cases (52%) on contrast-enhanced CT. Non-enhanced CT scan revealed calcification in 21 cases (50%). As the duration of Addison's disease increased, the presence of calcification and contour preservation increased concomitantly (p<0.001), whereas peripheral rim enhancement and mass-like enlargement decreased concomitantly on CT images (p<0.001). CONCLUSION: CT may be helpful in diagnosing adrenal tuberculosis when clinically suspected, and CT features are correlated to the clinical duration of Addison's disease.

Extramedullary plasmacytoma involving the bilateral adrenal glands on MR imaging.

We report here on a 64-year-old woman with extramedullary plasmacytoma involving the bilateral adrenal glands. Primary adrenal extramedullary plasmacytoma is extremely rare and only three cases of extramedullary plasmacytoma in the unilateral adrenal gland have currently been reported on. This case is of interest in that the bilateral adrenals were involved. In this article, we present the MRI findings and we briefly review the relevant literature.

Dynamic CT Evaluation of Tumor Vascularity in Renal Cell Carcinoma.

OBJECTIVE: The purpose of our study was to evaluate the correlation between the enhancement parameters of dynamic CT; the carcinoma tissue microvessel density (MVD, a hotspot method to provide a histologic assessment of tumor vascularity); and tumor nuclear grade in renal cell carcinomas. SUBJECTS AND METHODS: Twenty-four patients with histologically diagnosed renal cell carcinoma underwent dynamic enhanced CT. Enhancement parameters, slope of the time-density curve, the density difference before and after tissue enhancement (deltaH), tissue blood ratio (TBR), and area under the time-density curve (AR), were calculated for all lesions. Pathology slides corresponding to the CT plane were stained using mouse antihuman CD34 monoclonal antibody and H and E. Fuhrman nuclear grade was used. Vascular hot spots of microvessels were recorded. Spearman's rank correlation was performed to determine the strength of the relationship between enhancement parameters, MVD determinations, and tumor nuclear grade. RESULTS: MVD with CD34 staining revealed uneven distribution of positively stained vascular endothelial cells in renal cell carcinoma lesions. Heterogeneous distribution of contrast enhancement was seen among and within individual tumors. The tumors appeared as uneven patterns on time-density curves of renal cell carcinoma lesions. Enhancement parameters of H (median, 21.0 H; range, 2.2-105.8 H), TBR (median, 39%; range, 10.7-154.7%), AR (median, 1.58 H x sec; range, 0.23-3.67 H x sec), and slope (median, 2.76; range, 0.53-6.76) varied greatly. Renal cell carcinoma tissue MVD significantly correlated with all enhancement parameters of dynamic CT. The correlation coefficients (r) were 0.62, 0.54, 0.55, and 0.44, respectively, for delta H, slope, TBR, and AR (p < 0.0 5). All enhancement parameters did not significantly correlate with tumor nuclear grade. They were not predictive of nuclear grade. CONCLUSION: Enhancement parameters of dynamic CT may be suited to evaluate tumor vascularity in vivo. Dynamic enhanced CT images may reflect the heterogeneity of tumor angiogenesis on the basis of the correlation between enhancement parameters and MVD of renal cell carcinoma.

Single-level dynamic spiral CT of hepatocellular carcinoma: correlation between imaging features and density of tumor microvessels.

AIM: To investigate the correlation of enhancement features of hepatocellular carcinoma (HCC) revealed by single-level dynamic spiral CT scanning (DSCT) with tumor microvessel density (MVD), and to determine the validity of DSCT in assessing in vivo tumor angiogenic activity of HCC. METHODS: Twenty six HCC patients were diagnosed histopathologically. DSCT was performed for all patients according to standard scanning protocol. Time-density curves were generated, relevant curve parameters were measured, and gross enhancement morphology was analyzed. Operation was performed to remove HCC lesions 1 to 2 weeks following CT scan. Histopathological slides were carefully prepared for the standard F(8)RA immunohistochemical staining and tumor microvessel counting. Enhancement imaging features of HCC lesions were correlatively studied with tumor MVD and its intra-tumor distribution characteristics. RESULTS: On DSCT images of HCC lesions, three patterns of time-density curve and three types of gross enhancement morphology were recognized. Histomorphologically, the distribution of positively stained tumor endothelial cells within tumor was categorized into 3 types. Curve parameters such as peak enhancement value and contrast enhancement ratio were significantly correlated with tumor tissue MVD (r=0.508 and r=0.423, P<0.01 and P<0.05 respectively). Both the pattern of time-density curve and the gross enhancement morphology of HCC lesions were also correlated with tumor MVD, and reflected the distributive features of tumor microvessels within HCC lesions. Correlation between the likelihood of intrahepatic metastasis of HCC lesions with densely enhanced pseudocapsules and rich pseudocapsular tumor MVD was found. CONCLUSION: Enhancement imaging features of HCC lesions on DSCT scanning are correlated with tumor MVD, and reflect the intra-tumor distribution characteristics of tumor microvessels. DSCT is valuable in assessing the angiogenic activity and tumor neovascularity of HCC patients in vivo.

CT evaluation of spontaneously ruptured renal angiomyolipomas with massive hemorrhage spreading into multi-retroperitoneal fascia and fascial spaces.

BACKGROUND: Renal angiomyolipomas (RAMLs) can spontaneously rupture and induce hemorrhage that is usually confined to the perirenal space (PS) but may spread beyond the PS into other retroperitoneal fascia and fascial spaces, including up to the subdiaphramatic and down to pelvic extra-peritoneal regions. PURPOSE: To evaluate the computed tomography (CT) manifestations of renal angiomyolipoma (RAML) associated with spontaneous rupture and massive hemorrhage spreading beyond the PS into other retroperitoneal fascia and fascial spaces, including up to the subdiaphramatic and down to pelvic extra-peritoneal regions. MATERIAL AND METHODS: The CT scans of seven patients with spontaneously ruptured of RAMLs and massive hemorrhage (surgically and pathologically confirmed) were retrospectively reviewed. We evaluated the CT signs of the RAML itself and the regions with extensive retroperitoneal spreading after RAML rupture. RESULTS: THE CT MANIFESTATIONS OF SEVEN CASES WITH RAML SPONTANEOUS RUPTURE AND MASSIVE HEMORRHAGE INCLUDED THE FOLLOWING: (a) RAML signs: size (>4.0 cm, five patients; <4.0 cm, two patients), location (periphery, six patients; central portion, one patient), component (fat tissue included, seven patients), and boundary (poorly revealed, seven patients); and (b) signs of extensive retroperitoneal spreading after RAML rupture: involving the PS and extending beyond the PS (seven patients); spread to the pelvic extraperitoneal space (seven patients); attached to the subdiaphragmatic extraperitoneal region (four patients); and extended to the contralateral retroperitoneal spaces (six patients). CONCLUSION: CT scans clearly depict both the primary tumor and complicated signs of a spontaneously ruptured RAML with massive hemorrhage, which can affect other fascial planes and retroperitoneal spaces and can extend upward to the subdiaphragmatic region and downward to the pelvic extraperitoneal region or communicate with the contralateral side.

A study of multi-detector row CT scan on greater omentum in 50 individuals: correlating with anatomical basis and clinical application.

BACKGROUND: In view of the descriptions of the CT manifestations on the greater omentum (GO) were not precise and detailed enough in the previous literature, we tried to evaluate the radiologic-anatomical features of the GO and to address the related clinical implications for the radiologic diagnosis and surgical application. METHODS: We evaluated the GO by using multi-detector row CT (MDCT) scanning in 50 individuals correlating with anatomical basis and clinical application. Emphasis was placed on the following items: the anatomical distribution and location of the GO; the CT manifestations of the vasculature, fatty tissue and lymph nodes. RESULTS: The gastro-epiploic vessel, the landmark for delineating the GO, was visualized in 50/50 cases (100%). The gastro-colic vein was detected in 34/50 cases (68%). The free-hanging portion, 48 cases revealed, seemed to have the capability of 'migration': it is located in the subphrenic spaces in 9/48 cases (19%) and distributed in the right lower quadrant predominantly in 10/48 cases (21%). Three-dimensional reformatted images, obtained in five cases, demonstrated the return of the gastro-epiploic vein distinctly. Lymph nodes were rarely detected within the GO. CONCLUSION: The depicted omental vessels, visualized by using multi-planar reconstruction images together with three-dimensional reformatted images, played a crucial role in delineating the GO comprehensively. It can provide the valuable data for the radiologic diagnosis and surgical therapy planning including surgery of reconstruction, pancreas, portal hypertension as well as infections and neoplastic diseases.

Utility of multidetector CT in the diagnosis of gastric bare area invasion by proximal gastric carcinoma.

PURPOSE: To investigate the utility of multidetector CT (MDCT) in the diagnosis of gastric bare area (GBA) invasion by proximal gastric carcinoma (PGC). METHODS: Sixty-eight consecutive patients with biopsy-proven PGC underwent MDCT scan prior to gastrectomy. We evaluated the CT images separately for the site, size, depth, lymph node, and enhancement characteristic of each case. Each postsurgical stomach specimen was axially sectioned and comparison was made to determine the correlation between the CT findings and the pathological examination of each tumor bearing slice. RESULTS: The sensitivity for detecting GBA involvement in patients with PGC was 84%. MDCT correctly identified 32 of 38 patients with GBA invasion and 10/13 (77%) tumors with metastatic lymph node greater than 5 mm in GBA or subphrenic retroperitoneal space. 33/36 (92%) patients with tumor extension within the edge of the gastric wall and 28/32 (88%) patients with tumor infiltration into subphrenic fat were correctly identified. MDCT correctly predicted the infiltration of tumor into the diaphragm in all 14 patients and identified 6/11 (55%) patients with gastrophrenic ligament invasion. CONCLUSION: MDCT may be of value in assessing the important radiological characteristics of GBA invasion in patients with PGC.

Distribution and characteristics of hematogenous disseminated tuberculosis within the abdomen on contrast-enhanced CT.

BACKGROUND: The incidence of abdominal tuberculous lymphadenopathy never appears low. In addition to infecting the abdominal lymph nodes through the digestive tract, the tuberculosis bacteria can also infect the abdominal lymph nodes and extra-nodal organs through hematogenous dissemination. This study investigated contrast-enhanced CT features and anatomic locations of hematogenous disseminated tuberculosis involving abdominal organs. METHODS: Thirteen patients with documented hematogenous disseminated tuberculosis involving abdominal organs were recruited. Contrast-enhanced CT scanning was carried out in the abdomen of all patients. CT images were retrospectively analyzed for the size, attenuation, enhancement patterns, and anatomic distribution of the foci in infected lymph node, liver, spleen, and kidney. RESULTS: Hematogenous disseminated tuberculosis dominantly affected lymph nodes in the hepatoduodenal ligament (84.6%), the portacaval space (84.6%), the root of the mesentery (84.6%), the peripancreatic region (84.6%), the periceliac region (76.9%), the hepatogastric ligament (69.2%), and the upper and lower paraaortic region (both were 69.2%). Out of the 13 cases studied, 12 (92.3%) had lymphadenopathy with peripheral enhancement accompanied by multilocular appearance; 10 (76.9%) had homogeneous hepatomegaly; 13 (100%) had inhomogeneous splenomegaly accompanied by scattered low-density lesions with peripheral enhancement; and 8 (61.5%) had low-density lesions in the kidney with peripheral enhancement. CONCLUSION: Anatomically, peritoneal and retroperitoneal lymph nodes are most susceptible to hematogenous disseminated tuberculosis. The hepatomegaly manifested to be homogeneous in most cases while the splenomegaly is of frequently inhomogeneous attenuation. All these characteristics are closely related to the infection routes and pathologic features of abdominal hematogenous disseminated tuberculosis.

Differentiation between tuberculosis and primary tumors in the adrenal gland: evaluation with contrast-enhanced CT.

The aim of the present study is to determine imaging criteria for differentiating tuberculosis from primary tumors in the adrenal gland on contrast-enhanced CT. Non-contrast and contrast-enhanced CT features in 108 patients with adrenal tuberculosis (n = 34) and primary tumor (n = 74) were retrospectively assessed for the location, size, calcification and enhancement patterns. The primary tumors included 41 adenomas, 11 pheochromocytomas, 4 carcinomas, 3 lymphomas, 6 myelolipomas, 6 ganglioneuromas, 2 neurilemmomas and 1 ganglioneuroblastoma. Biochemical investigation was performed for all patients. Of the tuberculosis cases, 31 (91%) invaded with bilateral involvement, while 7 (9%) of the primary tumors invaded with bilateral involvement (P < 0.001). Tuberculosis often showed calcification (20 of 34; 59%), whereas primary tumors infrequently showed calcification (6 of 74; 8%; P < 0.001). Low attenuation in the center with peripheral rim enhancement was more commonly seen in tuberculosis (16 of 34; 47%) than in primary tumors (7 of 74; 9%; P < 0.001). In the determination of tuberculosis, the highest sensitivity (91%) and accuracy (91%) were obtained with bilateral involvement, and the highest specificity (99%) was obtained with the contour preserved. In the determination of primary tumors using a combination of having unilateral involvement and being mass-like, the outcome was a sensitivity of 91%, specificity of 94% and accuracy of 92%. CT findings can differentiate tuberculosis from a primary tumor of the adrenal glands with high sensitivity and an acceptable specificity when combined with the endocrinological examination.