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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: The abdominal and retroperitoneal lymphatic system is characterized by numerous anatomic variations. Our objective is to review MR lymphographic features of normal anatomy and abnormal conditions., Conclusion: MR lymphography is a noninvasive technique that is well suited for the examination of abdominal and retroperitoneal lymphatic vessels.

Objective: Pelvic magnetic resonance imaging (MRI) studies are widely used to assess the rectum, anal canal, and their environment. The purpose of this article is to review the current role of MRI in the evaluation of diseases involving the ischiorectal fossa and their imaging features., Conclusions: The radiologist plays an essential role in the evaluation of some conditions typically located in this space and of other conditions that occasionally involve this area or invade the ischioanal space. The accurate assessment of these diseases that MRI provides further cements its role as the primary technique for the evaluation of pelvic pathology.

The main problem associated with rectal cancer treatment is tumor recurrence. Randomized controlled studies have shown that adjuvant preoperative radiation therapy is effective for reducing local recurrence. These studies have also demonstrated that there are groups of rectal cancer patients with differing degrees of risk for local recurrence. At one end of the spectrum is the low-risk group: patients with superficial rectal cancer, who can be treated with surgery alone. At the other end is the high-risk group: patients with a close or involved resection margin at total mesorectal excision, the very advanced tumors that require a longer course of chemotherapy and radiation therapy, and extensive surgery. Paramount for this selection and differentiated treatment is a reliable preoperative test that can be used to distinguish these groups of patients. In this review article, we will discuss the role of high-resolution phased array MRI among the other imaging modalities such as endorectal MRI, endorectal US, and CT. We will also discuss and illustrate MR imaging results in terms of T stage, circumferential resection margin, locally advanced rectal cancer, and N stage.

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.

Diagnosis of incidental adrenal masses is a real challenge to radiologists. The most common incidental tumors of the adrenal gland are adenomas and metastases. This article presents our experience with uncommon adrenal incidentalomas. Most of the magnetic resonance imaging characteristic features are demonstrated. When possible, they are correlated with the findings at gross and microscopic analysis, to help in understanding the mechanisms by which magnetic resonance imaging may aid in the characterization of the incidental adrenal mass.

Purpose: To retrospectively compare the clinical manifestation and magnetic resonance (MR) imaging features of liver adenomatosis with pathologic findings., Materials and Methods: This study had institutional review board approval, and informed consent was waived. Twenty patients were classified on the basis of pathologic findings into three groups: those with a steatotic, those with a peliotic, and those with a mixed (steatotic and peliotic) form of liver adenomatosis. MR images were reviewed in consensus by two abdominal radiologists, and findings were compared with the pathologic classification. Statistical evaluation was performed with the Student t test., Results: All patients were women (mean age, 39 years +/- 10 [standard deviation]). Lesions of the steatotic form (n = 7) showed (a) a mean diameter of 6.3 cm +/- 1.7, (b) slightly hyperintense signal on T2-weighted images, (c) hyper- or isointense signal on T1-weighted images with a signal dropout with fat suppression sequences, and (d) moderate enhancement at the arterial phase with no delayed enhancement. Lesions of the peliotic form (n = 7) showed (a) a somewhat larger size (8.3 cm +/- 3.6), (b) markedly hyperintense signal on T2-weighted images, (c) iso- or hyperintensity on T1-weighted images with no signal dropout with fat suppression sequences, and (d) strong arterial enhancement and persistent enhancement at the portal and delayed phase. Lesions of the mixed form (n = 6) included a combination of imaging features of the steatotic and peliotic forms. Lesions, however, were significantly larger in the mixed form than in the steatotic form (10.3 cm +/- 4, P < .05)., Conclusion: There are three patterns of MR imaging features of liver adenomatosis that are associated with three pathologic forms (steatotic, peliotic, and mixed).

Objective: The objective of this pictorial essay is to provide a review of the diseases involving the rectal wall with an emphasis on the key clinical and radiologic differentiating features., Conclusion: A wide spectrum of disease processes can involve the rectum in adults. MRI is the technique of choice in the definitive diagnosis of these disease conditions, mainly because of its superior tissue contrast differentiation.

Pelvic magnetic resonance (MR) imaging is useful for identification of postoperative changes, complications, and disease recurrence in patients who have undergone surgery for primary or recurrent anorectal disease. Commonly used interventions include treatment for anorectal carcinoma: anterior rectal resection with or without creation of different colic anastomoses and abdominoperineal excision with or without pelvic reconstruction (omentoplasty, placement of myocutaneous flaps). Other common interventions include treatment for inflammatory bowel disease (coloproctectomy with or without creation of an ileoanal anastomosis and ileal pouch) and treatment for fistulas (placement of flaps or setons). Postoperative anatomic changes and formation of scar tissue can usually be identified with consecutive MR imaging examinations. Pelvic MR imaging is an accurate technique for assessment of complications including anastomotic leakage, septic complications such as fistulas and abscesses, neoplastic recurrence, and other less common complications (perineal hernia, peritoneal pseudocyst). The sophisticated surgical procedures used in rectal surgery can alter normal anatomy and make image interpretation difficult. Thus, familiarity with the appearances of postoperative anatomic changes, complications, and tumor recurrence is essential for accurate MR imaging evaluation after surgery for anorectal disease., (Copyright RSNA, 2006.)

Magnetic resonance imaging (MRI) and magnetic resonance cholangio-pancreatography (MRCP) features were analyzed in the diagnosis of seven surgically resected hepatobiliary cystic tumors with reference to histopathological data. Homogeneity, size, location, signal intensity, presence or absence of septa and/or nodules and MRCP features of the lesions were studied. Histological evidence demonstrated six biliary cystadenoma (BCA) including four pseudo-ovarian stroma (POS) and one biliary cystadenocarcinoma (BCAC). Cystic lesions (3-15 cm in diameter) were homogeneous in the six BCA, heterogeneous in the one BCAC, and were located in the left and right liver, respectively. On T2-weighted images all lesions were hyperintense. On T1-weighted images hypointensity was found in three BCA (all serous fluid, including one POS), isointensity was found in the three others (two mucinous and one hemorrhagic fluid, including three POS) and in the one BCAC (containing mucinous fluid). Septas were present in all cases and nodules only in the one BCAC. On MRCP a hyperintense cystic lesion was found in all cases and a bile ducts dilatation in two BCA and the one BCAC. Gadolinium-enhanced MRI in combination with MRCP is a valuable tool for the diagnosis of BCA or BCAC. However, no specific information is gained for POS detection.

Objectives: To evaluate MR imaging in detecting and characterizing secondary reactive synovitis and correlate the results with arthroscopy., Materials and Methods: Retrospective study of 10 patients referred for MR imaging and arthroscopy of the knee or shoulder. The diagnosis of reactive synovitis was confirmed by arthroscopy and pathological examination. Synovial thickening was graded at MRI as follows. Grade 0: normal; grade 1: diffuse synovial thickening; grade 2: nodular synovial hypertrophy; grade 3: pseudotumoral synovial mass., Results: Synovitis was described at MRI in 8 cases. There were 2 false negative results on MR imaging for the knee. Synovitis was secondary to knee trauma and rotator cuff tear or surgery of the shoulder. On arthroscopy, all synovial lesions were detected and confirmed at pathology. Synovitis was not detected at MRI (grade 0) in 20% of cases. Synovitis appeared diffuse (grade 1) in 30%, nodular (grade 2) in 30% and pseudotumoral (grade 3) in 20%. Bony erosions were adjacent to synovial thickening in 5 cases., Conclusion: Reactive synovitis can occur after trauma. MR imaging is useful in detecting and evaluating secondary reactive synovitis. Arthroscopy and synovial biopsy are necessary to exclude infectious or tumoral synovitis.

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.

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.

Primary leiomyosarcoma of bone is a rarely reported tumor of elderly subjects. It usually shows an aggressive osteolytic pattern on plain radiographs and involves predominantly the metaphyses of long bones. We report a case of primary leiomyosarcoma of bone, which is atypical by its epiphyseal location, a non-aggressive pattern on plain radiographs and its MR imaging features.

Background and Purpose: Sensorineural hearing loss (SNHL) is a rare complication of stapes surgery that may arise for many reasons. Usually, the pathogenesis of SNHL can be established by clinical and CT examinations. The purpose of this study was to evaluate the utility of MR imaging when CT findings are normal or not contributive., Methods: Eleven patients with SNHL (in some instances, associated with vertigo) after stapedectomy, in whom CT showed no well-defined cause, were examined by MR imaging., Results: MR studies established the additional findings of reparative intravestibular granuloma (n = 2), intralabyrinthine hemorrhage (n = 1), and bacterial labyrinthitis (n = 1). In five cases, MR findings were similar to CT findings. In two cases, CT and MR results were normal. Revision surgery was performed in five patients and confirmed the MR findings in each case., Conclusion: If CT is not contributive as to the origin of SNHL and vertigo occurring after stapes surgery, then MR imaging may be helpful in these patients.

Lyme disease involves multiple organ systems including in 10-15% of cases, the nervous system. Cranial neuropathies are observed in the second stage of the disease. The facial nerve is the most frequently affected nerve (20-30%). Facial nerve enhancement may be associated with cochleovestibular nerve abnormalities and can mimick an intracanalicular pseudomass. We present post-gadolinium enhancement of multiple cranial nerves associated to an intracanicular enhancement illustrated in a patient referred for a facial nerve palsy and presenting a Lyme disease. We discuss the differential diagnosis.

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.

We report the use of MRI in the diagnosis, follow-up and therapeutic management of three cases of intralabyrinthine Schwannoma. The diagnosis was based on the history and initial and follow-up MRI findings. The main feature suggesting the diagnosis was a nodular intralabyrinthine mass of low signal intensity on T2-weighted images, and high or isointense signal on T1-weighted images (relative to cerebrospinal fluid), which showed contrast enhancement. Follow-up imaging showed growth of the tumour in one patient. One patient underwent surgery for severe tinnitus. To detect these lesions, MRI should be focussed on the inner ear, using thin-section T2-weighted and T1-weighted images before and after contrast medium. MRI allowed informed surgical planning.

A case of chronic chemical meningitis occurring after a radical mastoidectomy is reported. Imaging and surgical findings were suggestive of a dissemination of cholesteatoma debris within the subarachnoid spaces. Chemical meningitis has been described in epidermoid and dermoid cyst rupture. This report illustrates that clinicians should be aware of this possible complication. Skull base imaging is mandatory before considering the diagnosis of idiopathic meningitis. Only treatment of the abnormal communication between cerebrospinal fluid and middle ear may eradicate the origin of this rare meningitis.

Purpose: To distinguish malignant from osteoporotic acute vertebral collapses., Materials and Methods: Sixty-three osteoporotic and 30 malignant vertebral collapses were studied in 51 patients (aged 33-88 years) with T1-weighted magnetic resonance (MR) images (n=93), gadolinium-enhanced T1-weighted images (n=72), and T2-weighted images (n=53)., Results: Four findings were suggestive of osteoporosis: retropulsion of a bone fragment (10 osteoporotic cases vs 0 malignant cases), preservation of normal signal intensity on T1-weighted images (43 vs four), return to normal signal intensity after gadolinium injection (42 vs four) with horizontal bandlike patterns, and isointense vertebrae on T2-weighted images (28 vs two). Six findings were suggestive of malignancy: convex posterior cortex (21 malignant cases vs four osteoporotic cases), epidural mass (24 vs 0), diffuse low signal intensity within the vertebral body on T1-weighted images (23 vs 12) and in the pedicles (24 vs four), high or inhomogeneous signal intensity after gadolinium injection (17 vs 0) and on T2-weighted images (17 vs 0)., Conclusion: Gadolinium-enhanced and unenhanced MR images are useful in the differentiation of vertebral collapses.

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.

Purpose: To look for central nervous system abnormalities as possible causes of intractable hiccups., Methods: Of a series of 50 patients with chronic (ie, lasting more than 48 hours) hiccups, a prospective study identified a subgroup of 9 patients with no clinical or gastroesophageal abnormalities (according to endoscopy, pH monitoring and manometry). We performed in all 9 patients brain and upper cervical cord MR examination with precontrast and postcontrast T1- and T2-weighted sequences. A study of the last cranial nerves was done with thin T2-weighted imaging (constructive interference in a steady state sequence). The cervical cord and parapharyngeal space were systematically explored using coronal T2- and sagittal T1-weighted imaging., Results: Five of these 9 patients had definite MR abnormalities located in the temporal lobe (3 cases), cerebellopontine angle (1 case), or areas of high signal intensity compatible with demyelination (1 case). The relationship between hiccups and infratentorial abnormalities in 2 cases was doubtful (vascular loop and prominent posterior condylar canal). MR findings in 2 cases were considered normal., Conclusions: Brain MR is a useful investigation in patients with chronic hiccups when gastroesophageal lesions are either excluded or too mild to account for an intractable hiccup.

Purpose: To describe the magnetic resonance (MR) imaging features of hepatic adenoma and correlate these findings with histopathologic findings., Materials and Methods: MR findings of 51 pathologically proved hepatic adenomas in 29 consecutive patients were retrospectively analyzed. T1- and T2-weighted spin-echo (SE) images were obtained in all patients, and contrast material-enhanced MR images were obtained in 16 patients., Results: At pathologic analysis, a peripheral rim, observed in 16 (31%) hepatic adenomas, corresponded to pseudocapsule, and tumor heterogeneity, observed in 26 (51%) lesions, corresponded to hemorrhagic necrosis and peliosis. Hyperintensity on T1-weighted SE images was observed in 30 (59%) adenomas; 10 (67%) of 15 hepatic adenomas were hyperintense on contrast-enhanced gradient-echo images, and 13 (45%) of 29 were hyperintense on delayed contrast-enhanced T1-weighted SE images., Conclusion: Presence of a peripheral rim, heterogeneity, and hyperintensity are common features of hepatic adenoma.

Purpose: To compare three-dimensional time-of-flight magnetic resonance (MR) angiography, MR imaging, and transfemoral four-vessel angiography in diagnosis and follow-up of cervical artery dissection., Materials and Methods: Eighteen patients with 19 extracranial internal carotid artery and five vertebral artery dissections were included in this prospective study. Blind interpretation of MR and angiographic images was made by two independent radiologists., Results: MR angiography was more accurate than MR imaging in diagnosis of carotid dissection, although the difference was not statistically significant. In carotid artery dissection, respective sensitivity and specificity were 95% and 99% for MR angiography and 84% and 99% for MR imaging and in vertebral artery dissection were 20% and 100% for MR angiography and 60% and 98% for MR imaging., Conclusion: MR angiography is a reliable, noninvasive method for use in diagnosis and follow-up of extracranial internal carotid artery dissection. In vertebral artery dissection, however, conventional angiography remains useful.

Nuclear magnetic resonance has shed new light on our understanding of osteonecrosis of the femoral head. It is at present the most sensitive and most specific imaging technique for the diagnosis of this condition. Studies involving correlations between MR images and anatomical findings have facilitated the understanding of tissue changes responsible for magnetic appearances. However, all problems are not resolved. At an early stage, fortunately almost always asymptomatic, false negative MRI or MR findings similar to those of algoneurodystrophy of the hip can be encountered. The aim of this article is to pinpoint the current status of these questions on the basis of a review of the recent literature. The contribution of MRI with injection of Gadolinium and future prospects are also discussed.

Neurofibromatosis is classified into two types. Type 1, NF1 or von Recklinghausen's disease, consists of skin and bone lesions as well as central nervous system tumours arising at the expense of glial tissue: optic tract gliomas, glioblastomas, astrocytomas and "hamartomas". Type 2 consists almost exclusively of CNS tumours arising at the expense of nerve envelopes: Schwannomas, meningiomas.

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.

The non neoplastic diseases of the nasopharynx are uncommon especially in adults. Cyst of pharyngeal bursa or Thornwald cyst are located in the supero-posterior nasopharynx, in the location of the normal pharyngeal bursa which open into the pharyngeal mucosa. When it persists, a cyst can develop if the orifice becomes occluded. The have a characteristic and distinctive C.T. and N.M.R. aspects, as presented in this paper, well circumscribed round midline mass, sparing muscles lateral as well as posterior, with an high signal in T1 and T2 N.M.R. sequences. No discussion with other pathologic conditions is useful because carcinoma, adenoid and pharyngeal polyp, or Killian's polyps haven't this configuration.