Mesenteric lymph nodes: detection and significance on MDCT

OBJECTIVE: Unsuspected mesenteric lymph nodes are frequently found on abdominal CT scans in everyday clinical practice. What to do with these findings has not been well established. The purpose of this study is to document the incidence of mesenteric lymph nodes in a previously healthy population and to provide guidelines for further management. MATERIALS AND METHODS: We examined the CT scans of 132 consecutive patients (84 men and 36 women; age range, 12-90 years; mean age, 43 years) who presented to the emergency department after experiencing blunt abdominal trauma. Twelve patients were excluded because they had disease processes known to be associated with lymphadenopathy. All imaging was performed using 3.2-mm collimation on MDCT scanners with IV contrast material. Two radiologists evaluated the images by consensus and recorded the presence of mesenteric lymph nodes greater than 3 mm in the short axis. Lymph node size, number, and location (central, peripheral, or right lower quadrant) were documented. All studies were reviewed on a PACS workstation. RESULTS: Of the 120 patients with otherwise normal CT scans, 47 had mesenteric lymph nodes greater than 3 mm. Of these 47 patients, 22 (47%) had five or more lymph nodes detected. Twenty-five (53%) of the 47 patients had four or fewer nodes. The mean size of the largest nodes was 4.8 mm (range, 3-9 mm), and the mean size of the nodes found per patient was 3.6 mm (range, 3-6 mm). These nodes were identified only at the mesenteric root in 32 patients (68%), only in the mesenteric periphery in eight patients (17%), and only in the right lower quadrant in five patients (11%). Nodes were identified in more than one location in two patients (4%). CONCLUSION: Incidental finding of mesenteric lymph nodes is common, reflecting more widespread use of thin-collimation MDCT and PACS workstations. In general, these nodes are small, measuring less than 5 mm. Such nodes when found in an otherwise healthy population are clinically insignificant and require no further imaging.     

活动性克罗恩病肠系膜淋巴结的CT 影像学研究

目的：探讨活动性克罗恩病(CD)肠系膜淋巴结的 CT 影像学特征。方法回顾性分析经内镜、病理证实的54例活动性 CD 患者的64排螺旋 CT 影像表现,重点观察肠系膜淋巴结的分布、大小、数目、形态及强化情况。结果38例(70.4%)CD 患者出现肠系膜淋巴结增大,总数为242个,其中83.5%(202/242)的淋巴结位于病变邻近肠系膜根部,16.5%(40/242)的淋巴结位于肠系膜周边部;肠系膜根部的淋巴结较周边部的淋巴结稍大,平均最大短径分别为(8.57±2.26)mm、(5.38±0.19)mm;73.6%(178/242)的淋巴结呈卵圆形;增强后淋巴结出现均匀明显强化,强化率为0.53±0.09。结论活动性 CD 常引起肠系膜淋巴结增大,以肠系膜根部淋巴结受累较为明显。     

Granulocytic sarcoma of bowel: CT findings

PURPOSE: To evaluate retrospectively the computed tomographic (CT) findings of granulocytic sarcoma of the bowel. MATERIALS AND METHODS: The institutional review boards of all participating institutions approved this study and waived the requirement for informed consent. CT scans were retrospectively reviewed in eight patients (seven men, one woman; age range, 23-71 years; mean age, 46 years) with pathologically proved granulocytic sarcoma of the small and/or large bowel. CT findings were evaluated with regard to the sites, morphologic characteristics, and contrast material enhancement patterns of the lesions, along with other ancillary findings (ie, peritoneal and mesenteric infiltration, ascites, lymphadenopathy, bowel perforation, and obstruction). RESULTS: Eight patients had a total of 13 lesions in the bowel (of which eight were pathologically proved), involving the duodenum (n=1), jejunum (n=2), ileum (n=5), sigmoid colon (n=1), and rectum (n=4); multifocal bowel lesions were noted in four patients. The lesion varied in shape, with wall thickening alone in three of 13 lesions, an intraluminal polypoid mass in four, an exophytic mass in one, and a combination of findings in five. Contrast material enhancement, relative to the back musculature, showed isoattenuation in seven lesions, hyperattenuation in four, and hypoattenuation in two. Five of eight patients had multiple peritoneal masses with diffuse mesenteric or peritoneal infiltration. Ascites was present in six of eight patients; lymphadenopathy (especially in the mesentery), in five; bowel perforation, in two; and bowel obstruction, in one. CONCLUSION: Granulocytic sarcoma of the bowel is characterized by variability in shape and contrast enhancement and has a high predilection for mesenteric and peritoneal spread.     

Parasternal sonography of the internal mammary vessels: technique, normal anatomy, and lymphadenopathy

Metastasis to the internal mammary lymph nodes adversely affects the disease-free interval and long-term survival in women with breast carcinoma. Since staging of disease in this lymphatic chain is rarely performed at the time of definitive surgical treatment, noninvasive methods have been advocated. The authors present their preliminary experience with a sonographic technique for evaluating the internal mammary lymph nodes, artery, and vein. Longitudinal and transverse images of the first through fourth parasternal rib interspaces were acquired with a 5.0- or 7.5-MHz linear-array real-time system. The method was evaluated prospectively in 36 control subjects and in seven patients (six with metastatic breast cancer and one with lymphocytic lymphoma) who had enlarged internal mammary lymph nodes at thoracic computed tomography (CT). The longitudinal scans routinely demonstrated the internal mammary vessels in the upper interspaces. Lymphatic structures were not identified in the control group. In contrast, sonographic findings corresponding to the CT findings of lymphadenopathy were present in all seven patients. The authors believe that parasternal sonography is a promising technique that merits further study.     

Lymphadenopathy in primary biliary cirrhosis: CT observations

The authors retrospectively evaluated computed tomographic (CT) scans obtained in 21 patients with primary biliary cirrhosis, 13 of whom subsequently underwent liver transplantation. Evidence of enlarged lymph nodes, primarily in the gastrohepatic ligament and porta hepatis, was seen on CT scans in 17 patients (81%). Lymphadenopathy also occurred in unusual sites for benign adenopathy, including the paracardiac (24%) and mesenteric (19%) lymph nodes. Surgical or autopsy confirmation of enlarged lymph nodes was made in 13 patients, and histologic analysis of the specimens revealed reactive hyperplasia, sinus hyperplasia, sinus histiocytosis, fibrosis, or normal architecture in these enlarged nodes. The authors conclude that lymphadenopathy is a frequent CT finding in primary biliary cirrhosis and that recognition can help prevent misdiagnosis of lymphoma or metastatic disease.     

CT evaluation of lymph node status at presentation of prostatic carcinoma.

Computed tomographic (CT) studies performed within a general oncology service in 104 consecutive patients with prostatic carcinoma were reviewed retrospectively to assess the incidence and distribution of lymphadenopathy. All patients were staged with CT at initial presentation, had normal skeletal scintigrams and were candidates for radical radiotherapy. The likelihood of lymphadenopathy was associated with increasing T-stage. 57 of the 92 (62%) patients without lymph node enlargement had local disease confined to the prostate (T2 or less) compared with only two of the 12 (17%) patients with enlarged nodes. Lymph node enlargement was more likely with a primary tumour of poorly differentiated histology. 12 patients (11.5%) had lymphadenopathy by established CT criteria; six with pelvic nodal enlargement alone and six with enlargement of pelvic and retroperitoneal nodes. In all patients pelvic nodal enlargement predominated and no patient had isolated retroperitoneal lymphadenopathy. Our findings indicate that CT staging studies of prostatic cancer do not need to include the retroperitoneum if there is no lymphadenopathy at or below the aortic bifurcation.     

Ileocecal tuberculosis: CT and radiologic evaluation

The CT and radiologic findings in 11 patients (five with AIDS and six without AIDS) with ileocecal tuberculosis are described. On CT scans, five cases showed mild circumferential wall thickening of the terminal ileum and cecum, thickening of the ileocecal valve, and a few regional nodes. One case presented as nonspecific small-bowel obstruction. In five patients a more characteristic CT appearance was detected: preferential thickening of the ileocecal valve and medial wall of the cecum, exophytic extension engulfing the terminal ileum, and massive lymphadenopathy with low-density areas consistent with caseation necrosis. Patients with AIDS had a more severe form of involvement than those who did not have AIDS. Barium studies showed ileocecal changes consistent with an inflammatory process. In conjunction with barium enema, CT is helpful in the initial evaluation of ileocecal tuberculosis, showing the location and extent of intestinal and mesenteric involvement in most cases. Characteristic CT findings are seen when the inflammatory process is severe.     

Parasternal sonography of the internal mammary lymphatics in breast cancer: CT correlation

The purpose of this study was to evaluate the efficacy of parasternal ultrasonography (US) in diagnosing internal mammary lymph node metastases in breast cancer, an important site of occult metastases, adversely affecting the disease-free interval and long-term survival. Thirty-five patients who were diagnosed with breast cancer were examined for internal mammarian lymph node (IMLN) involvement with parasternal US, and results were correlated with computed tomography (CT). Longitudinal and transverse images of the first through sixth parasternal rib interspaces were evaluated with a 7.5-MHz linear-array transducer. The enlarged nodes were demonstrated as discrete, spherical or ovoid hypoechoic lesions in six cases with parasternal US, and corresponding CT scans confirmed the presence of lymphadenopathy. Our results suggest that parasternal US may be helpful in the evaluation of IMLN metastases in breast cancer as a part of staging the disease.     

Ultrasound in Crohn's disease of the small bowel

OBJECTIVE: The purpose of this work is to prospectively evaluate high resolution ultrasonography with graded compression in the ability to detect Crohn's disease of the small bowel (CDSB) together with its complications and activity signs, compared with enteroclysis, CT and immunoscintigraphy in the mirror of the final diagnosis. METHODS AND MATERIAL: In a series of 73 consecutive patients, who were referred for enteroclysis with suspected Crohn's disease of the small bowel computed tomography (CT), ultrasound (US), immunoscintigraphy with 99mTc labeled monoclonal antigranulocyte antibody (AGAb) examinations were performed within 10 days from each other. For the final evaluation the diagnosis of CDSB was based on combination of clinical and enteroclysis findings (73 cases) and in 17 cases additional surgical and pathological data were available. The results of other modalities were blinded to the radiologists performing and reading out the exams. The diagnostic values of each modality was assessed also in those 18 patients, who had early Crohn's disease. In the group of 43 patients with proven CDSB who had all the four imaging modalities, the modalities were compared in their ability to demonstrate various pathological conditions related to CD. Increased (>500 ml/min) flow measured by Doppler US in the superior mesenteric artery and increased color signs in the gut wall seen by power Doppler sonography were compared to CDAI. RESULTS: Of the 73 patients the combination of enteroclysis and clinical tests demonstrated CDSB in 47. The sensitivity, specificity and accuracy of ultrasound were 88.4, 93.3 and 90.4%, respectively. Enteroclysis was the most accurate method. CT was more sensitive than US, but less specific. The accuracy of US, CT and scintigraphy were similar. In the group of 18 patients, who had early CDSB, the sensitivity of US decreased to only 67%, CT and scintigraphy had higher values. Intra- and perimural abscesses, and sinus tracts were also more frequently visualized by US, especially if they were small. US was superior than CT in detecting stenoses and skip lesions, but inferior to enteroclysis. US and CT detected more fistulas, than enteroclysis. Compared to CT, US detected more cases with mesenteric lymphadenopathy, equal cases with abscesses and free peritoneal fluids. In detecting mesenteric inflammatory proliferation CT, and in detecting colonic involvement CT and immunoscintigraphy were slightly superior than graded compression US. Patterns of mural stratification detected by ultrasound correlated well with the enteroclysis severity stages. There was only 59% agreement between increased superior mesenteric artery flow detected by Doppler sonography and CDAI, and 60.5% agreement between increased number of Color pixels in the gut wall measured by power Doppler and increased CDAI. CONCLUSION: High resolution graded compression sonography is a valuable tool for detecting small intestinal Crohn's disease. It has similar diagnostic values as CT. However in early disease the sensitivity substantially decreases. In known Crohn's disease for following disease course, evaluating relapses and extramural manifestations US is an excellent tool. Doppler and Power Doppler activity measurements do not correlate well with the more widespread clinical activity index.     

Small bowel disease in children: diagnosis with CT

The computed tomographic (CT) scans of 22 children with small bowel disease and those of 110 children with no small bowel disease were analyzed by two observers who were blinded with respect to clinical history and final diagnoses in order to determine which CT findings reliably indicated neoplastic, inflammatory, or noninflammatory processes. Bowel-wall thickening was the most reliable sign of disease. Five of six patients (83%) with bowel-wall thickness greater than 1 cm had neoplastic disease. Nine of ten patients (90%) with bowel-wall thickness between 3 mm and 1 cm had inflammatory disease, while four of six patients (66%) with wall thickness less than 1 cm and increased attenuation of mesenteric fat or an increase in the number of mesenteric vessels had noninflammatory edema. The presence of mesenteric masses was not a helpful sign for differentiating various disease processes. The results of this retrospective study suggest that the identification and classification of small bowel disease in children is possible from the objective analysis of CT findings.     

Mycobacterium genavense infection in AIDS: imaging findings in eight patients

This retrospective study included eight HIV-positive patients with a M. genavense infection. Seven of these patients had a CT scan of the abdomen and a US examination, whereas one patient with pulmonary symptoms had conventional chest radiographs and thin-section CT scan of the thorax. Multiple large retroperitoneal and mesenteric lymph nodes were demonstrated in seven patients; low-attenuation centers within enlarged nodes were identified in two patients. On CT scans two cases showed circumferential wall thickening of the proximal small bowel with a deep ulceration in one of these patients. Additional findings included focal lesions in the liver (n = 1), spleen (n = 2), splenomegaly (n = 6), and hepatomegaly (n = 4). The CT scans from the thoracic examination demonstrated multiple diffuse nodular infiltrates in both lungs. M. genavense infection should be considered in the differential diagnosis of AIDS patients with CD4 counts below 100 cells/mm³ presenting with abdominal lymphadenopathy, multinodular or homogeneous hepatosplenic enlargement and circumferential thickening of the small bowel wall. Received: 28 March 2000/Revised: 3 July 2000/Accepted: 6 July 2000     

Periportal tuberculous adenitis: CT features

The computed tomographic (CT) findings in six patients with periportal tuberculous adenitis were reviewed retrospectively to analyze the main morphologic features of the disease. In all patients, hypodense lymph nodes were observed close to the porta hepatis, with peripheral enhancement seen after administration of contrast material. In one patient, this hypodense adenopathy was associated with homogeneous, normally enhancing lymph nodes. These different features on the CT scans could signify the evolving pathologic stages of the disease, with early noncaseating granulomas and subsequent caseation necrosis. Recognition of these hypodense lymph nodes, especially in patients at risk, should help optimize the correct diagnosis of periportal tuberculous adenitis.     

CT of interpectoral lymph nodes

The presence of lymph nodes between the pectoralis major and minor muscles (Rotter's nodes) has been noted in the anatomic and surgical literature. We analyzed the appearance of the interpectoral space and nodes on chest CT scans of 25 patients without known chest wall abnormalities or causes for lymphadenopathy. In some of these cases small structures were detected in the interpectoral fat that could be either vessels or nodes. In addition we studied chest CT scans in six patients with interpectoral adenopathy due to metastases from breast cancer. The nodes were oval soft-tissue densities ranging from 1.5 X 1 cm to 3.5 X 3 cm in diameter.     

Mesenteric adenitis: CT diagnosis of primary versus secondary causes, incidence, and clinical significance in pediatric and adult patients

OBJECTIVE: Our objective was to determine the clinical significance of mesenteric adentitis when detected on CT. MATERIALS AND METHODS: Mesenteric adenitis was considered present if a cluster of three or more lymph nodes measuring 5 mm or greater each was present in the right lower quadrant mesentery. If no other abnormality was detected on CT, then mesenteric adenitis was considered primary. If a specific inflammatory process was detected in addition to the lymphadenopathy, then mesenteric adenitis was considered secondary. Patients with a known neoplasm or HIV infection were excluded. Three separate groups of patients were examined for the presence and cause of mesenteric adenitis. Group 1 consisted of 60 consecutive patients prospectively identified with mesenteric adenitis on CT examinations. Group 2 consisted of 60 consecutive patients undergoing abdominal and pelvic CT for evaluation of blunt or penetrating abdominal trauma. Group 3 consisted of 60 consecutive patients undergoing abdominal and pelvic CT with acute abdominal symptoms. In all patients, the indication for imaging was documented, and the size of the largest lymph node, when present, was measured. In patients with mesenteric adenitis, the CT findings, clinical history, and clinical or surgical follow-up were subsequently evaluated to determine the cause of mesenteric adenitis. RESULTS: In the 60 patients prospectively identified with CT findings of mesenteric adenitis (group 1), 18 (30%) of 60 had primary mesenteric adenitis. The remaining 42 patients (70%) had an associated inflammatory condition that was established on CT as the likely cause of mesenteric adenitis. Mesenteric adenitis was present in none (0%) of the 60 patients in group 2 and in five (8.3%) of 60 patients in group 3. CONCLUSION: The incidence of mesenteric adenitis in patients with and those without abdominal pain is low. When evidence of mesenteric adenitis is present on CT examinations, usually a specific diagnosis can be established as its cause.     

Value of MR imaging in evaluating focal fatty infiltration of the liver: preliminary study.

Focal fatty infiltration of the liver is a well-known entity that occasionally mimics metastatic disease on ultrasonographic (US) and computed tomographic (CT) scans and requires biopsy for diagnosis. To determine if high-field-strength magnetic resonance (MR) imaging might be useful in the differential diagnosis of the lesions, the authors compared US, CT, and MR findings in three patients with biopsy-proved fatty hepatic lesions. Areas of focal fatty infiltration were hyperechoic on US scans and had low attenuation on CT scans. No mass effect of the lesions on vascular structures or liver contours was observed, particularly on contrast material-enhanced CT scans. For all three patients, MR findings suggested the correct diagnosis by demonstrating focal high signal intensity on spin-echo T1- and T2-weighted images. On the basis of these preliminary findings, it appears that focal fatty infiltration of the liver may be differentiated from metastatic disease by means of high-field-strength MR imaging.     

Duodenal neoplasms: role of CT

In a retrospective study of 14 cases of duodenal neoplasms evaluated by computed tomography (CT), there were four primary adenocarcinomas of the duodenum, one lymphoma, five metastatic carcinomas, two duodenal lipomas, one villous adenoma, and one leiomyoma. The CT findings were diagnostic in patients with duodenal lipomas. In 11 cases, a primary origin of the mass was clearly identifiable in the duodenum. Thickening of the bowel wall, tumor necrosis, ulceration, and intraluminal defects were common. The relationship of the masses to adjacent structures was clearly shown on CT scans. Extraluminal extent of the lesion was noted on CT scans in seven patients; however, at surgery only four of six were found to have extramural disease. The presence of adenopathy, liver metastases, and vascular and mesenteric invasion were also demonstrated on CT scans. Twelve patients underwent upper gastrointestinal tract series. A duodenal abnormality was seen in all 12 patients, but the extramural extent and distant metastatic involvement could not be seen on these examinations. CT scans allowed the accurate staging of eight of ten malignant lesions and thus helped in the management of duodenal tumors.     

Mesenteric adenitis and acute terminal ileitis: US evaluation using graded compression

One hundred seventy consecutive patients with clinical suggestion of acute appendicitis were studied by ultrasound (US) with the examiner using the graded compression technique. In 14 patients, the only US findings consisted of enlarged mesenteric lymph nodes in combination with mural thickening of the terminal ileum. This was consistent with the findings at surgery in four patients and with the results of barium studies in seven patients. In nine of 14 patients, stool cultures were performed, eight of which were positive for Yersinia enterocolitica. None of these 14 patients finally proved to have appendicitis. In a patient with acute pain in the right lower quadrant whose appendix cannot be visualized sonographically and whose US findings consist of enlarged mesenteric lymph nodes and mural thickening of the terminal ileum, the diagnosis is probably mesenteric adenitis and acute terminal ileitis. Appendectomy should be avoided in this condition.     

Multifocal fatty infiltration of the liver: report of six cases

Images of computed tomography (CT), ultrasonography (US), angiography and radionuclide imaging were analyzed in six cases of multifocal fatty infiltration of the liver. Histologic confirmation of fatty infiltration was obtained in one patient by percutaneous biopsy. In the remaining patients, presumptive confirmation of the diagnosis was based on the CT number in one patient and partial or complete resolution of the lesions on repeat CT scans or US in 4 patients. CT and US were performed in all six patients. CT scans demonstrated multiple round areas of low attenuation within both lobes of the liver in all cases. US studies showed hyperechoic foci in three cases and diffuse inhomogeneous hyperechogenicity in three cases. Hepatic arteriograms in five cases and liver scintigrams in four cases showed no evidence of space-occupying lesions. In all cases, the lesions completely or partially resolved in follow-up CT and US, and in four cases the lesions disappeared within two months, so follow-up examinations within about 2 months are necessary to differentiate these from liver neoplasms.     

Cross-sectional imaging in ureter tumors: findings and staging accuracy of various modalities.

We present cross-sectional imaging findings in eight patients with ureter tumors. Eight patients were examined by computed tomography (CT), seven by ultrasonography (US), and five by magnetic resonance imaging (MRI). All the lesions were detected by the three modalities. All modalities were accurate in excluding the periureteral invasion and lymphadenopathy in Stages 1 and 2 tumors. While CT and MRI identified the periureteral invasion and lymphadenopathy in four patients with advanced tumors, US failed to show the local invasion in three of four patients. Nevertheless, enlarged retroperitoneal lymph nodes could be detected sonographically in the three Stage 4 tumors. CT and MRI appear to have a high diagnostic sensitivity and staging accuracy in ureter tumors. Although US detects ureter tumors efficiently, this technique seems to be unreliable in showing local invasion in a substantial number of patients.     

Pulmonary lymphangioleiomyomatosis: CT findings

Lymphangioleiomyomatosis, a rare disease occurring in women of childbearing age, is characterized by proliferation of smooth muscle in pulmonary lymphatic channels and mediastinal and abdominal lymph nodes. Chest radiographs typically reveal interstitial disease with normal lung volume. Pneumothorax and pleural effusions may be present. CT scans in eight patients with biopsy-proved pulmonary lymphangioleiomyomatosis were reviewed. The prominent feature of the disease was multiple thin-walled cysts throughout the lungs, best visualized on scans made with 1.5-mm collimation. Mediastinal and/or retrocrural lymphadenopathy, often not appreciated on the chest radiograph, was present in four of eight patients. CT can suggest a diagnosis of lymphangioleiomyomatosis when diagnosis by clinical presentation and chest radiographs is uncertain.