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Surgery for the treatment of colorectal diseases has been evolving rapidly recently. In addition to classical surgical procedures (colectomy, abdominoperineal resection), new surgical procedures include coloproctectomy with creation of an ileoanal anastomosis and ileal pouch, pelvic reconstructions (omentoplasty, placement of myocutaneous flaps) and creation of different colic anastomoses after anterior rectal resection. Even if computed tomography and fluoroscopic contrast examinations are still commonly used to assess postoperative changes and complications, especially infections, pelvic magnetic resonance imaging is useful to depict postoperative changes, detect complications such as fistulas and tumor recurrence in patients who have undergone surgery for primary or recurrent rectal disease. The main surgical techniques, their respective indications and postsurgical imaging features will be discussed. The main complications and imaging work-up will also be reviewed.

Objective: Our purpose was to examine the computed tomographic findings in 13 patients with acute deep venous thrombosis (DVT) of central veins of the neck, chest, and abdomen in whom major perivenous inflammatory changes were noted., Methods: During a 10-year period, 13 patients with acute DVT of 21 central veins and marked perivenous inflammatory changes on computed tomography were identified. Computed tomography images were assessed for location of DVT and pattern of perivenous changes., Results: The perivenous changes took the form of a rounded or lobulated perivenous bulky mass (massive pattern or tumorlike) in 5 patients and of infiltrative changes in the other 8 patients. Direct visualization of the thrombotic vein was possible in 8 patients. Follow-up examinations (range, 6-36 months; mean, 15 months) demonstrated resolution of perivenous inflammatory changes with anticoagulation therapy in all cases., Conclusion: Perivenous inflammatory changes around the thrombotic vein presented as a rounded or lobulated perivenous bulky mass that may mimic a tumor or as infiltrative perivenous changes.

The imaging features of infectious and non-infectious pathologies in HIV patients with AIDS (less than 200 CD4/mm3) are illustrated. Opportunistic infections, tumors and vascular pathologies have variable appearances based on the degree of immunosuppression and patient compliance with opportunistic infection prophylaxis. Because of advances in retroviral treatments and wider use of anti-infectious prophylaxis, thoracic pathologies in AIDS patients are less frequent but must nonetheless be recognized, and diagnosis should be suggested in patients with unknown serologic status.

The purpose of this study was to report a new technique for localization of hepatic tumors that are poorly visible with CT fluoroscopy. Forty-three hepatocellular carcinomas were not visible with CT fluoroscopy. A 22-gauge Chiba end-hole needle was inserted in the approximate location of a lesion estimated on the basis of anatomical landmarks demonstrated on both previous MR and CT images. We injected 3 ml of a mixture of nonionic contrast material and saline solution. Following the first injection, contrast solution filled the hepatic lesion in 29 of 43 cases. In 8 of 43 cases, contrast solution was distributed in the normal surrounding liver. In 7 of these 8 cases, repositioning allowed us to adjust the needle in the tumor. In the other 6 of 43 cases, contrast solution spread within capsule or pseudocapsule (pattern 3). In all 6 cases, repositioning allowed to adjust the needle in the tumor. This new technique allows an accurate localization of hepatic tumors that are poorly visible with CT fluoroscopy.

Objective: Our objective is to describe pouchography, CT, and MRI features of the J-shaped pouch, both normal and with pouch-related complications., Conclusion: Pouchography is performed before closure of the loop ileostomy to assess the integrity of the ileal pouch and anastomosis. CT and MRI can be performed when postoperative complications, such as small-bowel obstruction, pouchitis, leakage, abscess, intramural hematoma, desmoid tumor, or recurrent Crohn's disease, are suspected.

The ileocecal area is a relatively short segment of the gastrointestinal tract but may be affected by pathologic conditions that are either common throughout the gastrointestinal system or exclusive to this area. These conditions include benign and malignant tumors, inflammatory processes (appendicitis, diverticulitis, epiploic appendagitis, Crohn disease), infectious diseases, and miscellaneous conditions (cecal ischemia, typhlitis, cecal volvulus, duplication cyst). The various components of the ileocecal area (cecum, appendix, ileocecal valve, terminal ileum) are close to one another, so that these conditions may involve more than one anatomic structure, thereby creating a diagnostic dilemma. The evaluation of various parameters (eg, stratified enhancement pattern of the thickened bowel wall, degree of thickening, extent and location of bowel wall involvement, degree of fat stranding relative to the degree of wall thickening) and associated findings (lymph nodes, mesenteric stranding, abscess and sinus tracts, fatty proliferation, solid organ abnormalities) will help narrow the differential diagnosis. Multi-detector row computed tomography (CT) is considered the best imaging examination for the evaluation of the ileocecal area. Consequently, the radiologist should be familiar with the multi-detector row CT features of the spectrum of diseases affecting this area to help ensure correct diagnosis and appropriate treatment., (Copyright RSNA, 2006.)

Patient's age no longer is a major factor when discussing the diagnosis and treatment of hepatobiliary and gastrointestinal diseases. However, discussing with the physician in charge of the patient is the only adequate way to propose the quickest, least invasive and most comfortable imaging modality that will give a proper answer to the clinical problem. Cross sectional imaging, especially ultrasound, CT and in some cases MRI, plays an important role in the diagnosis of these diseases.

Myositis ossificans circumscripta is a benign pathology of soft tissue occurring in young patients often after localized trauma. Histological and radiological appearances may mimic a malignant neoplasm, mainly sarcoma. We report a case characteristic of myositis ossificans circumscripta, to illustrate diagnostic arguments which are based on their appearance on conventional radiographs, computed tomography and magnetic resonance imaging and on their changes with time.

Objective: The purpose of our study is to evaluate the distribution of acetic acid mixed with iodinated contrast agent during percutaneous acetic acid injection on CT fluoroscopy for hepatocellular carcinoma., Conclusion: Monitoring acetic acid distribution on CT fluoroscopy can detect extratumoral diffusion and may optimize the distribution of acetic acid in hepatocellular carcinoma.

Cutaneous neuroendocrine carcinoma, first described in 1972, is an aggressive disease usually occurring in sun-exposed skin. Other sites have been described, however; such tumors occasionally occur within the nasal fossa. A high rate of metastasis (>30%) explains the poor prognosis. Descriptions of the imaging features of these tumors, mainly located in cutaneous region, are rare. We therefore present the imaging features of two cases of Merkel cell carcinoma involving the sinonasal region, suggestive of a hypervascular tumor.

We report a case of adenosarcoma arising in hepatic endometriosis. Both CT and MR scans demonstrated a huge heterogeneous mass containing septated, thick-walled cystic lesions. After enlarged right hepatectomy, the patient was asymptomatic with no abnormalities at liver and abdominal CT scan at 2-year follow-up.

After a brief review of the pertinent anatomy of joint compartments and main ligaments of the wrist, the authors present the technique of wrist arthrography and CT arthrography. They discuss the normal and pathological patterns. The main indications are the chronic painful wrist and posttraumatic wrist. Imaging can reveal ligament defects (particularly scapholunate ligament, or lunotriquetral ligament), triangular fibrocartilage tears, capsular defects, cartilage thinning, foreign bodies, synovial ganglia or synovitis of the wrist.

Peritoneal mesothelioma is a rare, either benign or malignant tumor of the peritoneum. We retrospectively analyzed the imaging features of six malignant and three benign peritoneal mesothelioma. Asbestos exposure was proven in three of the six malignant cases and in none of the three benign cases. Ascites was found in seven patients (78%), peritoneal masses in eight patients (88%), small peritoneal nodules in six patients (66%), parietal peritoneal thickening in six patients (66%), thickened mesentery in five patients (55%) and pleural plaques as well as nodules in one patient. These imaging features support the diagnosis of peritoneal mesothelioma but do not allow differentiation between benign and malignant forms of peritoneal mesothelioma.

We describe the MRI features of a rhinoscleroma with orbital extension. This benign bacterial and granulomatous lesion of the paranasal sinuses gave homogeneous low intensity on T2-weighted images and enhanced with gadolinium. It could simulate a malignant sinonasal tumour or a fungal sinusitis; the diagnosis must be considered in patients from endemic areas.

Inflammatory aneurysm of the abdominal aorta (IAAA) is a variant of atherosclerotic aneurysm that is characterized by inflammatory and/or fibrotic changes in the periaortic regions of the retroperitoneum [1, 2]. These inflammatory and/or fibrotic changes are probably the result of a local autoallergic reaction to certain components of atherosclerotic plaques [2]. This distinct entity has important implications, as the periaortic fibrotic tissue adherent to ureters, the duodenum, and the inferior vena cava may complicate surgical repair [1, 2]. The purpose of this essay is to illustrate the CT appearance of IAAA, with emphasis on the identification of IAAA and differentiation from conventional aortic aneurysms, evaluation of the involvement of adjacent structures by the periaortic fibrosis, and evaluation of the retroperitoneum after aneurysmal repair to analyze the resolution or the persistence of the periaortic fibrosis.

Purpose: The value of computed tomography (CT) for differentiating benign from malignant causes of nontraumatic acute vertebral collapse (AVC) (associated with pain of less than 3 months duration) was evaluated., Materials and Methods: The CT findings of 34 benign (osteoporotic) and 32 malignant (metastatic or myelomatous) nontraumatic AVCs were compared., Results: The following CT findings were significantly more frequent in benign AVCs: cortical fractures of the vertebral body without cortical bone destruction, retropulsion of a bone fragment of the posterior cortex of the vertebral body into the spinal canal, fracture lines within the cancellous bone of the vertebral body, an intravertebral vacuum phenomenon, and a thin diffuse paraspinal soft-tissue mass (PSTM). The following CT findings were significantly more frequent in malignant AVCs: destruction of the anterolateral or posterior cortical bone of the vertebral body, destruction of the cancellous bone of the vertebral body, destruction of a vertebral pedicle, a focal PSTM, and an epidural mass., Conclusion: CT can help distinguish benign from malignant causes of nontraumatic AVC.

In 13 patients presenting as lethal midline granuloma (LMG), computed tomography proved essential for determining the extent of the disease, guiding biopsy and planning radiotherapy. Magnetic resonance imaging (MRI) was also helpful for the latter, because it could distinguish fluid retained within the paranasal sinuses from solid masses and tumour from granulation tissue; it was of little value for detecting bone lysis. Eight of the 13 patients proved to have T-cell lymphoma, two had Crohn's disease, in one the lesion was factitious and two had granulomas without diagnostic histological features.

10 patients with symptoms of mandibular neuralgia formed the basis of this study. They were studied by both enhanced CT and MRI. MRI, better than CT, easily permits distinction between intrinsic and extrinsic lesions and detects involvement of the cavernous sinus and meninges. Moreover, because of its multiplanar imaging capability, and ability to portray exquisite anatomic details and characteristic tissue signal intensity, MRI is helpful in the evaluation of tumor involvement for biopsy and preoperative planning for these deep tumours.

Infections of face and neck represent serious and potentially life threatening conditions that are sometimes difficult to differentiate from neoplastic tumours, especially in subacute clinical forms. Conventional radiographic techniques offer interest for cervical masses, except Ultra-Sonographic exam, in sites regarding vascular axes, but carries little value for evaluating their spread into the different cervical spaces. On the other hand, C.T. is valuable to precise the location and the extent and to determine its inflammatory nature by studying the fats and the aponeurosis around it. It help in the analysis of associated adjacent signs: soft tissue swelling, extensive obliteration of adjacent fats, swelling of cervical aponeurosis, thickening of adjacent muscles. These findings are documented by the study of fourteen patients, admitted in St-Antoine hospital. All abscesses, except one, were easy to diagnose because of their low central attenuation. False negative cases are possible and noted by other authors. So, in absence of response to appropriate therapy, surgery is necessary to eliminate a misdiagnosed abscess. Furthermore, it's sometimes possible to suspect an etiology (foreign body, tuberculosis).