CT enteroclysis: a pictorial essay

The objective of the CT-enteroclysis is to distend the entire small intestine equally and sufficiently using a nasojejunal probe and an enteroclysis catheter for administration of a neutral opacifying agent. Today this is the best radiological method available to explore the small intestine because of its good spatial resolution and the rapidity of the exam. It is a high-performance exam when searching for transmural and extramural pathologies, in particular small tumoral lesions. It remains less effective in the exploration of anomalies of the lumen's mucosal lining, contrary to videocapsule endoscopy and the double-balloon enteroscope. It has been recognized that the CT-enteroclysis is a high-performance examination that should replace the small-bowel follow-through exam. However, there are undeniable disadvantages: higher does of radiation, patient discomfort during placement of the enteroclysis catheter, false-positive results, long interpretation time, and the impossibility of exploring the endoluminal aspect of the intestinal mucosal lining. All radiologists should therefore become familiar with the problems involved with this exam and its signs and patterns, which are illustrated in this pictorial review.     

Image segmentation in digital mammography: comparison of local thresholding and region growing algorithms.

Local thresholding and region-growing algorithms are developed and applied to digitized mammograms to quantify the parenchymal densities. The algorithms are first evaluated and optimized on phantom images reflecting varying image contrast, X-ray exposure conditions, and time-related changes. The difference between the segmentation results of the two techniques is less than 6% on the phantom images and 11% on the mammograms. The agreement between the computerized procedures and a manual one is in the range of 74-98%, depending on the breast parenchymal pattern and segmentation algorithm. The results show that computerized parenchymal classification of digitized mammograms is possible and independent of exposure.     

Genitourinary trauma: a pictorial essay

Genitourinary trauma is often overlooked in the setting of acute trauma. Usually other more life-threatening injuries take precedence for immediate management. When the patient is stabilized, radiologic imaging often plays a key role in diagnosing insults to the upper and lower genitourinary tract in the setting of trauma. Our aim is to provide a pictorial assay of imaging findings in upper and lower tract genitourinary trauma from a variety of mechanisms including blunt trauma, penetrating trauma, and iatrogenic trauma. A patient archiving and communication system will be used to review imaging studies of patients at our institution with genitourinary tract trauma. Cases of renal, ureteral, bladder, urethral, penile, and scrotal trauma will be considered for inclusion in our study. Multimodality imaging techniques will be reviewed. The imaging and pertinent findings that occur in various types of genitourinary trauma are outlined. Genitourinary trauma is often missed in the frenzy of acute trauma. It is important to have a high suspicion for injury especially in severe trauma, and in particular clinical settings. Although often not life threatening, recognizing the diagnostic imaging findings quickly is the realm of the astute radiologist so appropriate urologic management can be made.     

Imaging bicipitoradial bursitis: a pictorial essay

Skeletal Radiology - Although bicipitoradial bursitis is not commonly seen, when it does occur, it can frequently lead to diagnostic difficulty, mimicking either a soft-tissue tumor or infection....     

MRI in lung cancer: a pictorial essay

Imaging studies play a critical role in the diagnosis and staging of lung cancer. CT and 18-fluorodeoxyglucose positron emission tomography CT (PET/CT) are widely and routinely used for staging and assessment of treatment response. Many radiologists still use MRI only for the assessment of superior sulcus tumours, and in cases where invasion of the spinal cord canal is suspected. MRI can detect and stage lung cancer, and this method could be an excellent alternative to CT or PET/CT in the investigation of lung malignancies and other diseases. This pictorial essay discusses the use of MRI in the investigation of lung cancer.     

Pathology of extrinsic ligaments: a pictorial essay

The role of the extrinsic ligaments, together with the intrinsic ligaments, appears to be much more important than previously thought in the setting of carpal stability. The anatomy and pathology of the extrinsic wrist ligaments is complex. Magnetic resonance imaging (MRI) with thin slices is essential for visualization. This article describes the pathological appearance of the extrinsic palmar and dorsal radiocarpal and ulnocarpal ligaments on MRI, correlated with arthroscopy (performed by two skilled hand surgeons), clinical findings, and follow-up. High-resolution MRI, especially using isotropic three-dimensional sequences with orthogonal multiplanar reconstructions on 3T MR systems, allows detailed depiction of many of the extrinsic ligaments affected in carpal injuries. Recognition of ligament abnormalities is improved by intra-articular or intravenous injection of contrast before the examination. Both techniques may help to determine the precise localization, size, and extent of dorsal and palmar radiocarpal and ulnocarpal ligament lesions. Further experience with these techniques is needed to define the place of MRI in the management of traumatic wrist injuries.     

Interpolation algorithms for digital mammography systems with multiple detectors

RATIONALE AND OBJECTIVES: In some full-field digital mammography systems, multiple detectors are abutted together, and the physical gaps between adjacent detectors produce seams between the resultant subimages. In this study, a variety of interpolation algorithms for estimating the missing information in the seams were compared, and their effect on image quality was evaluated. MATERIALS AND METHODS: Eight representative interpolation algorithms were selected, including nearest neighbor, one-dimensional and two-dimensional weighting, mean value, one-dimensional and two-dimensional polynomial, and one-dimensional and two-dimensional cubic spline interpolation methods. These methods were applied to digital mammograms and phantom images. The effectiveness of each algorithm was evaluated for accuracy and geometric distortion. RESULTS: These interpolation algorithms offered similar accuracy in estimating missing image information. The weighting, polynomial, and cubic spline interpolation algorithms introduced less geometric distortion than the nearest neighbor and mean value interpolation algorithms. All algorithms were more effective in estimating larger, lower-contrast features (such as breast masses) than in estimating smaller, higher-contrast features (such as breast microcalcifications). Small microcalcifications within the seams cannot be recovered with interpolation. The probability of a microcalcification in a seam is small, however, and the failure to image a few microcalcifications of a cluster generally does not substantially alter diagnostic performance. CONCLUSION: In the development of full-field digital breast imaging systems, appropriate interpolation algorithms can satisfactorily fill in narrow gaps between adjacent detectors. The one-dimensional weighting interpolation method seems an effective and efficient choice.     

MR imaging of the postoperative knee: a pictorial essay.

Magnetic resonance (MR) imaging of the postoperative knee has become more common because more arthroscopic repair procedures are being performed. The most common procedures include partial meniscectomy and meniscal repair, anterior cruciate ligament (ACL) reconstruction, and cartilage repair procedures. Specific findings of a retorn meniscus following meniscal repair or partial meniscectomy are increased signal intensity extending through the site of repair on T2-weighted images, displaced meniscal fragments, and abnormal signal intensity at a site distant from the repair. Findings of ACL graft disruption on T2-weighted MR images include absence of intact graft fibers and increased signal intensity similar to that of fluid within the expected region of the graft. Partial tears of the graft appear as areas of increased signal intensity affecting a portion of the graft with some intact fibers still present. An impinged ACL graft may appear to be draped over the anterior inferior edge of the intercondylar roof or be posteriorly bowed. Localized anterior arthrofibrosis appears on T1-weighted MR images as a focal nodular lesion of low signal intensity that is anterior to the ACL graft in the intercondylar notch and is indistinguishable from adjacent joint fluid. On T2-weighted images, the nodule is well differentiated from high-signal-intensity joint fluid. Finally, MR imaging has been shown to be accurate in the evaluation of cartilage repair tissue. Knowledge of the normal MR imaging appearance of the knee after the more common repair procedures will allow radiologists to recognize complications associated with such procedures.     

MR imaging of non-CNS fetal abnormalities: a pictorial essay.

The recent popularity of prenatal magnetic resonance (MR) imaging has been associated with the development of ultrafast MR imaging techniques such as the single-shot fast spin-echo sequence. However, the majority of previous reports have concerned the fetal central nervous system (CNS) and chest disorders. MR imaging can demonstrate non-CNS fetal anatomy and pathologic conditions clearly. With its excellent tissue contrast, MR imaging provides information that supplements that provided by ultrasonography (US), especially in cases of neck, chest, and gastrointestinal lesions. Because of its large field of view, MR imaging allows evaluation of the relationship between a large lesion and adjacent structures. MR imaging should be considered if the diagnosis of a suspected non-CNS lesion is unclear at fetal US. MR imaging plays an important complementary role to US in cases of non-CNS fetal lesions and will be further accepted for fetal imaging in the future.     

Local complications after limb-salvage surgery for pediatric bone tumours: a pictorial essay.

The prognosis for patients with bone sarcoma treated with LSS has improved considerably over the past 2 decades, but this has also lead to an increase in the number of complications requiring treatment. Imaging plays an important role, not only in assessing the primary tumour, but also in identifying postsurgical complications. Plain radiography demonstrates the majority of the complications associated with LSS and remains the mainstay of follow-up imaging. Complications such as fractures are common and warrant frequent plain film follow-up. Imaging with scintigraphy, MRI and CT should be tailored to the patient's clinical history, type of surgery and suspected complications. A baseline postoperative bone scan examination can be helpful for comparisons with subsequent scans for the detection of complications. Sonography should be considered if infection is suspected. Finally, tumour recurrence may be frequent enough to consider more extensive use of MRI.     

Interventional radiology in renal emergencies: a pictorial essay

Emergency Radiology - Renal emergencies necessitate prompt diagnosis and management to stop active bleeding and retain kidney function. Causes of renal emergencies can be classified into traumatic,...     

Two unusual causes of dysphagia: a pictorial essay

Dysphagia was the presenting symptom in two adult patients. One had a mediastinal pancreatic pseudocyst, the other a pulmonary sling. The role of imaging methods in making the diagnoses is illustrated.     

Primary carcinoma of the gallbladder: a pictorial essay

This paper is an overview of the imaging characteristics of primary carcinoma of the gallbladder, based on the premise that more general knowledge of the imaging patterns of the primary tumor and its modes of spread might increase the likelihood of accurate preoperative diagnosis of this lesion. Primary tumor patterns discussed and illustrated are: (I) an intraluminal mass, (II) focal or diffuse thickening of the gallbladder wall, and (III) replacement of the gallbladder by a mass. Illustrated patterns of tumor spread include direct extension and lymphatic and hematogenous metastases.     

Anatomy of the ankle ligaments: a pictorial essay

Understanding the anatomy of the ankle ligaments is important for correct diagnosis and treatment. Ankle ligament injury is the most frequent cause of acute ankle pain. Chronic ankle pain often finds its cause in laxity of one of the ankle ligaments. In this pictorial essay, the ligaments around the ankle are grouped, depending on their anatomic orientation, and each of the ankle ligaments is discussed in detail.     

Magnetic resonance imaging phase encoding: a pictorial essay

A set of MRI images with various degrees of phase encoding were generated from the same raw data set. The resultant pictorial teaching aid is useful in developing an intuitive understanding of the mechanics and principles of phase encoding in two dimensional, Fourier transform magnetic resonance imaging.