Use of the Bard Memotherm self-expanding metal stent in the palliation of colonic obstruction

Background: Self-expanding metal stents (SEMS) are a recognized means of palliating large bowel obstruction due to colonic neoplasia. The literature mainly relates to the use of modified esophageal stents (expanded diameter, 18–22 mm) in the colorectum. Stent migration has been a common complication and may be related to expanded stent diameter. This series reports our experience with the Memotherm Colorectal SEMS (expanded diameter, 25–30 mm). Methods: Prospective data were collected from February 1999 to September 2000. Sixteen patients (age range = 61–99 years) were considered for the Memotherm Colorectal SEMS. Stents were inserted radiologically under fluoroscopic control. Outcome was classified as a technical success (stent in correct position and expanded) and a clinical success (colon decompressed, symptoms relieved, and bowels working). Results: Thirteen cases (81%) underwent successful SEMS placement. These were technically and clinically successful. Two cases required insertion of two overlapping stents to traverse long strictures. Three unsuccessful cases were emergency presentations in which a guidewire could not be passed across the lesion. Two of these were due to benign strictures and the third to extrinsic compression by ovarian carcinoma. Conclusion: In our experience, the Memotherm Colorectal SEMS was easy to use, was effective in the palliation of obstructing colorectal carcinoma, and appeared to reduce the risk of stent migration.     

Preoperative assessment of pancreatic malignancy using endoscopic ultrasound

Background: Endoscopic ultrasound (EUS) has been regarded as the most accurate modality for locoregional staging of pancreatic malignancy. However, several recent studies have questioned this. The current study assessed the accuracy of EUS in determining preoperative resectability of pancreatic neoplasia. Methods: A retrospective review was performed of patients with pancreatic malignancy who had preoperative EUS and underwent surgery. EUS-predicted resectability was compared with surgical resectability. Where available, accuracies of vascular and nodal staging were also assessed. Results: Forty-five patients were identified (mean age = 60 years, age range = 36–79 years). All patients underwent surgical exploration; vascular staging was available in 32 cases and 17 cases underwent surgical resection. The sensitivity, specificity, and accuracy of EUS in determining unresectability were 66%, 100%, and 78% respectively. Overall EUS stage concurred with surgical stage in 56%, greater than surgical stage in 4%, and less than surgical stage in 40%. Vascular staging on EUS had a sensitivity of 69% and a specificity of 100%. Accuracy of nodal staging was 71%. Conclusion: EUS had a high specificity for assessing unresectable pancreatic malignancy. This technique should be used to avoid unnecessary surgical exploration of incurable lesions. However, EUS had only a moderate sensitivity, and a proportion of patients staged preoperatively as having resectable disease will not be surgically resectable.     

PET-CT detection of abdominal recurrence of ovarian cancer: radiologic–surgical correlation

The diagnosis of recurrent ovarian cancer can be difficult on cross-sectional imaging, and variable sensitivities and specificities have been reported for positron emission tomography (PET). Combined functional and anatomic imaging with PET plus computed tomography (CT) potentially allows for improved detection of tumor masses. We investigated the sensitivity, specificity, and accuracy of PET-CT for the diagnosis of recurrent ovarian cancer. Sixteen women with previously treated ovarian cancer underwent imaging on a combined PET-CT scanner followed by surgery to assess for possible recurrent disease. The fused PET-CT images were retrospectively reviewed for recurrent disease, and the results of PET-CT were compared with the operative notes. Eleven of the 16 patients had recurrent disease at surgery. The sensitivity, specificity, and accuracy of PET-CT for disease detection on a per-patient basis were 72.7%, 40%, and 62.5%, respectively. For cases of malignant adenopathy (n = 7), 100% were detected on PET-CT. For peritoneal lesions no larger than 1 cm (n = 23), 13% were detected on PET-CT. For peritoneal lesions larger than 1 cm (n = 8), 50% were detected on PET-CT. The sensitivity of PET-CT for recurrent ovarian cancer is moderate in patients with low volume disease. A trial involving a larger number of patients with a spectrum of disease volumes is necessary to determine the impact of PET-CT in clinical practice.     

Ultrasound in abdominal tuberculosis

Background: The present study was done to emphasize the importance of ultrasound (US) and US-guided fine-needle aspiration biopsy (FNAB) in the diagnosis of abdominal tuberculosis. Methods: Sixty-six proven cases of abdominal tuberculosis were selected for this study. The diagnosis was based on clinical features, US observations, FNAB, operative findings, and responses to appropriate antitubercular treatment. The US findings were interpreted with regard to the involvement of lymph nodes, intestine, peritoneum, solid viscera, and abdominal abscesses. Patients with disease limited to the musculoskeletal and genitourinary systems were not included in the study. Results: Peritoneal tuberculosis was the most common form, of the wet ascitic type. Ascites was clear in 19 patients and complex in 17. Tuberculous lymphadenopathy was seen in 37 patients. There was a predilection of periportal, peripancreatic, and mesenteric locations compared with the degree of retroperitoneal involvement. Calcification and heterogeneous echotexture were seen in seven cases. FNAB confirmed the diagnosis of tubercular lymphadenopathy in 19 patients. Intestinal disease was seen in 14 patients. Hepatic or splenic involvement was seen as diffuse organomegaly; less commonly, focal lesions were seen. Conclusion: This combination of US findings in proper clinical settings are diagnostic of tuberculosis. FNAB confirms the diagnosis in lymphadenopathy, abscesses, and focal lesions of the viscera.     

Endolumenal ultrasonography in the diagnosis of pancreatic diseases

We evaluated the usefulness and limitations of endoscopic ultrasonography (EUS) in pancreatic mass lesions. EUS was useful in detecting small pancreatic mass lesions, especially ductal adenocarcinomas smaller than 20 mm and small islet cell tumors smaller than 10 mm. In some of these cases, characteristic echo patterns were specific and useful for differential diagnosis from focal pancreatitis. However, when EUS did not clearly delineate a tumor at the stenotic area of the main pancreatic duct, transpapillary pancreatoscopy and biopsy/cytology were sometimes effective to obtain a definitive diagnosis. EUS fine-needle aspiration should be performed in conjunction with imaging modalities when the differential diagnosis of a pancreatic mass is difficult to make. Although the value of EUS in cancer staging was overestimated, EUS in conjunction with spiral computed tomography or magnetic resonance imaging should be performed for such a purpose. Usefulness and limitations of intraductal ultrasonography (IDUS) also were evaluated. IDUS was useful in detecting carcinoma in situ and small tumors and in assessing parenchymal invasion and the intraductal spread of the tumor. IDUS was also useful in accurately localizing islet cell tumor and in differentiating benign from malignant cases of localized stenosis of the main pancreatic duct. Thus, EUS and IDUS are indispensable modalities in the diagnosis of pancreatic diseases.     

Hepatic involvement in hereditary hemorrhagic telangiectasia:

Hereditary hemorrhagic telangiectasia (HHT), also known as Rendu-Osler-Weber disease, is an autosomal-dominant vascular disease characterized by mucocutaneous or visceral angiodysplastic lesions (telangiectases and arteriovenous malformations) that may be widely distributed throughout the cardiovascular system. The recognition of mucocutaneous telangiectases, the occurrence of spontaneous and recurrent episodes of epistaxis, the presence of visceral involvement, and a family history of this disease are the clinical criteria that allow diagnosis. In comparison with skin, lungs, gastrointestinal tract, and brain involvement, hepatic involvement defined by clinical criteria alone has long been considered uncommon. Our experience with a large group of HHT patients, even those asymptomatic for liver involvement, demonstrates that it is more frequent than reported and is characterized by the presence of intrahepatic shunts, disseminated intraparenchymal telangiectases, and other vascular lesions. Congestive cardiac failure, portal hypertension, portosystemic encephalopathy, cholangitis, and atypical cirrhosis have been reported as possible serious complications related to this condition. Thus, a correct diagnosis is important, and diagnostic imaging has a fundamental role in detecting alterations involving the liver. The possibilities to perform a multiphasic study and to provide high-quality multiplanar and angiographic reconstructions, gives multidetector row helical computed tomography the ability to detect and characterize the complex anatomopathologic alterations typical of this disease.     

Proximal small bowel intussusceptions in adults: CT appearance and clinical significance

Background: According to the clinical literature, intestinal intussusception in adults is rare, is associated with a pathologic lead point, and is usually treated surgically. Nonobstructing small bowel intussusception has been reported as a transient finding on computed tomographic (CT) studies.Methods: We evaluated the radiographic and clinical findings in 24 patients who were found to have 26 proximal small bowel intussusceptions on abdominal CT scans performed for a variety of indications.Results: Twenty patients with intussusceptions had no evidence of small bowel obstruction. The transient and clinically insignificant nature of 22 intussusceptions in these 20 patients was proven radiologically (n = 14), surgically (n = 1), or by clinical follow-up (n = 7). These patients demonstrated a bowel-within-bowel pattern on multiple contiguous images and absence of strangulation or intestinal dilatation. No lead points were demonstrated in these patients. Three other patients had symptoms of low-grade small bowel obstruction and were treated conservatively. Extensive follow-up investigations showed no recurrence of intussusception or a lead point. One patient had high-grade obstructive intussusception with intestinal ischemia and required surgical resection of necrotic bowel.Conclusions: Proximal small bowel intussusceptions are likely to be transient and nonobstructive and unlikely to have a significant lead point.     

Dynamic MRI in indirect estimation of microvessel density,histologic grade,and prognosis in colorectal adenocarcinomas

The relations of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) parameters to microvessel density (MVD), histologic grade, and presence of metastasis were evaluated to establish new prognostic indicators in colorectal cancer (CRC). Fast-low angle shot DCE-MRI parameters (time-intensity curves, TICs; maximal relative enhancement within the first minute, E_max/1; maximal relative enhancement of the entire study, E_max; steepest slope of the contrast enhancement curve; and time to peak enhancement) of 21 CRCs (seven Duke stage B, 12 Duke stage C, and two Duke stage D) were retrospectively evaluated and correlated with corresponding postoperative MVD measurements, histologic grades, and presence of metastasis at 2 years. TICs were classified as type A in nine (43%), type B in seven (33%), and type C in five cases (24%). There was a significant difference between TIC types with regard to MVD (p < 0.05–0.001). Time to peak enhancement, steepest slope of TIC, and E_max/1 were strongly correlated with MVD (r = –0.765, p < 0.01; r = 0.681, p < 0.01; r = 0.634, p < 0.01; respectively). MVD, steepest slope of the enhancement curve, E_max/1, and E_max strongly correlated with histologic grade (r = 0.475, p < 0.05; r = 0.683, p < 0.01; r = 0.687, p < 0.01; r = 0.791, p < 0.01; respectively). There was a significant difference between groups of patients with and without metastasis with regard to histologic grade (p < 0.05) and two of the DCE-MRI parameters (p < 0.005 for E_max/1 and p < 0.05 for time to peak enhancement). Discriminant analysis correctly predicted the metastatic occurrence at 2 years in 90.5% of cases using E_max/1 (p < 0.001). Histologic grade resulted in lower rates of discrimination (66.7%; p < 0.05). DCE-MRI parameters may help in the prediction of MVD and histologic grade in CRC and may be used to predict therapeutic outcome.     

Arteriovenous malformation of the pancreas in a patient with gastrointestinal bleeding: helical CT findings

Dynamic computed tomographic (CT) findings of arteriovenous malformation (AVM) of the pancreas include strong enhancement or conglomeration of small hypervascular spots in the pancreas and early contrast filling of the portal vein during the arterial phase. We describe a case with pancreatic AVM in which we identified enlarged arterial feeders and draining veins as supportive findings of the diagnosis and ulceration into the pancreatic duct as a possible cause of gastrointestinal bleeding at contrast-enhanced CT.     

Use of thin-section,multidetector row helical CT images for coronal oblique reformations for optimal visualization of structures in the hepatoduodenal ligament

Multidetector row computed tomography (CT) can acquire abdominal images of unprecedented thinness in a single breath-hold. This study investigated whether acquiring source axial images at 1.25 mm as opposed to 2.5 mm would result in a perceptible difference in image quality for coronal oblique reformations. Similarly, the hypothesis that a slice pitch of 3:1 would be superior to 6:1 was evaluated. Twenty-nine CT studies were retrospectively evaluated. The images were divided into four groups: 1.25-mm axial images, pitch 3:1; 2.5-mm axial images, pitch 3:1; 1.25-mm axial images, pitch 6:1; and 2.5-mm axial images, pitch 6:1. Three radiologists evaluated by consensus the coronal oblique reformations for overall image quality and image quality of structures in the hepatoduodenal ligament and of nodal groups. Use of 1.25-mm rather than of 2.5-mm source axial images resulted in statistically significant better scores for overall image quality and visualization of the hepatic artery, portal vein, pancreatic duct, and nodal groups. However, a pitch of 3:1 rather than of 6:1 did not result in significant differences in ratings of image quality. Use of 1.25-mm rather than of 2.5-mm source axial images improves image quality when creating coronal oblique reformations for abdominal anatomy.     

Small bowel tuberculosis

We describe the radiologic appearances of small bowel tuberculosis as shown by enteroclysis. A total of 265 patients with proven small bowel tuberculosis seen over a period of more than one decade was evaluated. All patients had positive radiologic findings as shown on enteroclysis examination. Of the 265 patients with small bowel tuberculosis, 174 had isolated small bowel involvement with a normal ileocecal region, whereas 91 had associated noncontiguous involvement of the ileocecal region. The most common radiologic finding was the presence of strictures, noted in 62.7% of cases. Most strictures were short, concentric, and smooth in outline. These strictures were solitary or multiple and located mainly in the jejunum. Other radiologic findings were adhesions (21.8%), ulcerations (9.1%), and diffuse thickening of folds (6.4%). Complications noted were in the form of enteroliths, perforations, and fistulae. The radiographic findings of small bowel tuberculosis, although nonspecific, may indicate tuberculosis in a high-risk population.     

Isolated dissection of the superior mesenteric artery

Dissection of the superior mesenteric artery (SMA) not associated with aortic dissection is rare. The purpose of this study is to describe the computed tomographic (CT) findings of this condition. We studied the CT findings of six patients with isolated dissection of the SMA. CT demonstrated thrombosis of the false lumen or intramural hematoma (n = 4) and/or intimal flap (n = 4) in all six patients. Other CT findings were enlarged diameter of the SMA (n = 5), increased attenuation of the fat around the SMA (n = 5), and hematoma in the mesentery with hemorrhagic ascites (n = 1). CT is useful for the diagnosis of isolated dissection of the SMA, and increased attenuation of the fat around the artery is considered the key to the diagnosis when no definite findings are evident.     

CT virtual intravascular endoscopy of abdominal aortic aneurysms treated with suprarenal endovascular stent grafting

Background: We investigated the clinical applications of virtual intravascular endoscopy (VIE) in patients with abdominal aortic aneurysms (AAA) treated by endovascular stent grafting with a suprarenal component. Methods: Thirty-four patients with AAA undergoing endovascular stent grafting were included in the study (28 male, six female; mean age = 76 years). Helical computed tomography (CT) scanning was performed within 1 week after stent graft implantation. All patients received a Zenith/AAA endovascular graft with uncovered suprarenal struts 2.5 cm long placed around the level of the renal arteries. VIE images were created for each patient. The follow-up periods ranged from 3 to 18 months (mean = 8.3 ± 3.7 months). Results: Three of 34 celiac arteries, 22 of 34 superior mesenteric arteries, 32 of 34 right renal arteries, and 30 of 35 left renal arteries were affected by the suprarenal stent struts (wires) to different extents. VIE was able to demonstrate the struts, arterial ostia, and the strut/ostia configuration. Follow-up CT showed that all of these aortic branches were patent. Conclusion: Our preliminary experience has demonstrated that VIE is a novel imaging technique to visualize the three-dimensional intralumenal relationship of the aortic stent struts to the arterial ostia in patients with AAA after suprarenal stent graft placement.     

Peritoneal Coccidioidomycosis: a potential CT mimic of peritoneal malignancy

Peritoneal involvement is a rare extrapulmonary manifestation of coccidioidomycosis. We report a patient with meningeal coccidioidomycosis who was found to have multiple, globular, peripherally enhancing deposits in the peritoneal cavity at abdominal computed tomography, raising the consideration of peritoneal malignancy. Aspiration biopsy demonstrated peritoneal coccidioidomycosis. The particular computed tomographic findings of peritoneal coccidioidomycosis seen in this patient have not been previously described.     

Radiologic evaluation in planning surgery of renal tumors

The evolution in diagnostic imaging modalities, mainly in computed tomography (CT) and magnetic resonance imaging (MRI), have made it possible to extend the applications of these techniques from diagnosis to staging and surgical planning. Nowadays, the possibility to present images on different planes with an intrinsic resolution close to that of the original axial sections allows presentation of the kidney on sagittal, coronal, and oblique planes. Three-dimensional reconstructions can be obtained with different methods and have attained excellent image quality. Multidetector spiral CT presently is the best technique for planning surgery, but MRI also enables high-quality images to be obtained if state-of-the-art equipment is available. This update reviews the current status and possibilities of diagnostic imaging modalities in planning surgery of renal tumors.     

Imaging of the liver: a survey update of prevailing techniques for conventional CT scanning

Background A survey of the Society of Computed Body Tomography/Magnetic Resonance (SCBT/MR) was performed to assess current techniques in liver CT scanning.Methods The study was designed as an update to a study performed in 1987. The survey was distributed to 67 members of the SCBT/MR at 35 institutions.Results Twenty-six institutions responded. As in 1987, none relied solely on noncontrast scans. In 1987, only 54% (12/22) of institutions performed contrast-enhanced scans as their primary technique compared with 73% (19/26) in 1993. Ionic contrast was used exclusively in the earlier study, whereas in the present study 58% used nonionic contrast in the majority of cases and 38% used nonionic contrast routinely. In 1987, 41% performed scans with a power injector compared with 85% in the present study. Enhanced scans were performed during the contrast bolus in 36% of institutions in 1987 compared with 76% in this study. No institution relied on noncontrast scans alone. In the previous study the delay between injection and scanning was variable (0–60 s), whereas in the present study 83% specified a delay of 21–45s.Conclusion Significant refinements in CT technique, wider use of power injectors, utilization of nonionic contrast, and a more critical approach to optimize liver imaging have created a significant impact on the practice of liver CT.Dr. Silverman is supported in part by a Senior Research and Development Award from General Electric Medical Systems. Additional grant support provided by NY COMED Inc., Mallinckrodt Medical and Medrad Inc.     

Common bile duct diameters after endoscopic sphincterotomy in patients with common bile duct stones: ultrasonographic evaluation

Background: One of the most reliable, frequently used imaging techniques in cholestasis is ultrasonography (US) for the diagnosis of common bile duct (CBD) stones. Methods: In this study, changes in diameters of CBD were determined ultrasonographically before and after endoscopic sphincterotomy (ES) in 46 patients with stone-induced dilated CBD. Results: There was a significant decrease in CBD diameter measured 1 week after ES and extraction of stone (p < 0.001). In 87% of cases, the difference was more significantly pronounced during the first 24 h of ES. The mean CBD diameters on US were 13.70 ± 3.00 mm (10–21 mm) before and 9.13 ± 2.90 mm (4.2–18 mm) 24 h after endoscopic treatment (p < 0.001). After ES, six patients (13%) with inadequate decreases in CBD diameters were found to have residual stones. Conclusion: US can show residual stones in the CBD with the same efficacy as endoscopic retrograde cholangiopancreatography.     

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Background: One of the most reliable, frequently used imaging techniques in cholestasis is ultrasonography (US) for the diagnosis of common bile duct (CBD) stones. Methods: In this study, changes in diameters of CBD were determined ultrasonographically before and after endoscopic sphincterotomy (ES) in 46 patients with stone-induced dilated CBD. Results: There was a significant decrease in CBD diameter measured 1 week after ES and extraction of stone (p < 0.001). In 87% of cases, the difference was more significantly pronounced during the first 24 h of ES. The mean CBD diameters on US were 13.70 ± 3.00 mm (10–21 mm) before and 9.13 ± 2.90 mm (4.2–18 mm) 24 h after endoscopic treatment (p < 0.001). After ES, six patients (13%) with inadequate decreases in CBD diameters were found to have residual stones. Conclusion: US can show residual stones in the CBD with the same efficacy as endoscopic retrograde cholangiopancreatography.     

Early invasive colorectal carcinomas with submucosal invasion: radiographic characteristics with barium double contrast images

Background: We assessed the radiographic characteristics of early colorectal carcinomas with submucosal invasion (CCSI) with the use of double-contrast images. Methods: From 1989 to 1997, 193 patients with 196 CCSI lesions underwent double-contrast barium enema examinations. Three gastrointestinal radiologists retrospectively reviewed the radiographic characteristics of the lesions and classified them as protruding and depressed types by consensus. Further, subclassifying the protruding into lobular and smooth types was accomplished on the basis of surface structure. Each type was compared with pathologic findings of resected specimens. Results: The incidence of the protruding type was 98.0%, and that of the depressed type was only 2.0%. The proportion of smooth lesions was 49.0% for the protruding type; these had a mean diameter of 17.9 mm, which was significantly smaller than the 23.1 mm mean observed for lobular lesions (p < 0.01). Of the smooth lesions, 44.7% demonstrated massive invasion, whereas 91.8% of lobular lesions exhibited only slight or moderate invasion into the submucosa (p < 0.01). The extent of invasion of the smooth lesions was greater than that for their lobular counterparts in terms of venous and lymph node involvement. Conclusion: Almost all CCSIs could be identified radiologically as protruding lesions; these had a smooth rather than a lobulated surface and demonstrated greater malignancy, despite the smaller size. It is clinically important to discriminate these from other polypoid lesions in establishing patient treatment. Double-contrast imaging is useful for evaluation of the surface characteristics of CCSIs in barium enema studies.     

Evaluation of the permeability of pancreaticogastric anastomoses (PGA) with dynamic magnetic resonance pancreatography after secretin stimulation (secretin MRCP)

Background: Because some investigators have reported the systematic occurrence of exocrine pancreatic insufficiency after pancreaticoduodenectomy with pancreaticogastric anastomosis (PGA), we assessed PGA patency after pancreaticoduodenectomy. Methods: Nineteen patients underwent pancreaticoduodenectomy, and their PGAs were studied prospectively with secretin magnetic resonance cholangiopancreatography (MRCP). After administration of negative bowel contrast agent, single-shot fast spin-echo T2-weighted dynamic MR pancreatograms were obtained before and every minute for 12 min after secretin injection. Morphologic features of the pancreatic parenchymal and pancreatic duct were monitored (diameter and winding aspect of the pancreatic duct, pancreatic thickness, direct visualization of the anastomotic site). PGA permeability was classified into four grades, from 0 (obstruction) to 3 (good permeability). Pancreatic function was assessed by fecal-1 elastase concentration, fasting blood glucose, and fasting serum insulin level. Results: MRCP grades were 0 in two patients, 1 in four, 2 in five, and 3 in eight. The anastomotic site was visualized in 10 patients. Pancreatic parenchymal atrophy was discovered in four patients. There were statistically significant relations between secretin MRCP permeability grade and fecal-1 elastase concentration (p < 0.03) and between secretin MRCP permeability grade and pancreatic atrophy (p < 0.005). In contrast, fecal-1 elastase concentration was lower than the normal value in all but one case. There was no statistically significant relation between fecal-1 elastase concentration and other morphologic data. Conclusion: Secretin MRCP may indicate PGA stenosis or dysfunction, but it is not the only factor suggesting exocrine pancreatic insufficiency. Thus the major role of PGA may be the preservation of long-term endocrine function.