Staging of ureteral transitional cell carcinoma by CT and MRI

Intravenous urography and retrograde pyelography are the primary radiologic studies for detecting ureteral carcinoma but give limited information regarding stage of disease. Computed tomography (CT) and magnetic resonance imaging (MRI) delineate the extent of ureteral carcinomas with a high degree of accuracy by depicting the periureteral fat and presence or absence of lymphadenopathy. In selected cases, CT and MRI are valuable for assessing the presence or absence of tumor in a ureteral stump and for the differential diagnosis of ureteral obstruction. Five cases of ureteral carcinoma and 2 cases of stump carcinoma are presented with preoperative CT and/or MRI evaluation and staging.     

Editorial Commentary: How Does Magnetic Resonance Imaging Stack up in Comparison to Computed Tomography Imaging for Measurement of Glenoid Version?

Computed tomography (CT) has been the gold standard for measuring glenoid version in patients with glenohumeral osteoarthritis or instability. However, few studies have compared measurements of glenoid version on magnetic resonance imaging (MRI) versus CT. Clinicians should feel confident in assessing glenoid version on MRI in the absence of CT imaging. In fact, MRI could be comparable to CT even in cases where the entire scapula is not visible on MRI. A 5° difference in glenoid version between imaging modalities represents a clinically significant difference.     

Value of CT and MRI in malignant hepatobiliary tumors

Computed tomography (spiral-CT, multislice-CT, CT-angiography) and magnetic resonance imaging have been refined technologically within the last several years. The value of MRI in the diagnostic workup of malignant liver tumors has significantly increased. The reasons are the improvement of image quality, the reduction of acquisition time with the possibility of imaging during one breath-hold period, the introduction of liverspecific contrast materials (superparamagnetic iron oxide particles, hepatocellular contrast media), contrast-enhanced MR-angiography and magnetic resonance cholangiopancreaticography. MR imaging should be used--following ultrasound--more and more as primary imaging modality.     

Imaging of anorectal disease

BACKGROUND: Over the past two decades developments in imaging have changed the assessment of patients with anorectal disease. METHODS: The literature on imaging techniques for anorectal diseases was reviewed over the period 1980-1999. RESULTS: For the staging of primary rectal tumours, phased array magnetic resonance imaging (MRI) may be regarded as the most appropriate single technique. The combination of endosonography or endoluminal MRI with ultrasonography or spiral computed tomography yields similar results. All techniques have limitations both for local staging and in the assessment of distant metastases. MRI or positron emission tomography is preferable for tumour recurrence. For perianal fistula, high-resolution MRI (phased array or endoluminal) is the technique of choice. For constipation, defaecography is the preferred technique, nowadays with emphasis on functional information. The role of magnetic resonance defaecography is currently being evaluated. For faecal incontinence, endosonography and endoluminal MRI give similar results in detecting sphincter defects; endoluminal MRI has the advantage of detecting external sphincter atrophy. CONCLUSION: High-resolution MRI, endosonography and defaecography are currently the optimal imaging techniques for anorectal disease.     

Clinical staging of upper urinary tract urothelial carcinoma for T staging: Review and pictorial essay

Upper urinary tract urothelial carcinoma is staged using the TNM classification of malignant tumors. Preoperative TNM is important for treatment planning. Computed tomography urography is now widely used for clinical survey of upper urinary tract carcinoma because of its diagnostic accuracy. Computed tomography urography is recommended as the first‐line imaging procedure in several guidelines. Several reports stated that computed tomography urography is also useful for staging. However, no educational and practical reviews detailing the T staging of upper urinary tract urothelial carcinomas using imaging are available. We discuss the scanning protocol, T staging using computed tomography urography, limitations, magnetic resonance imaging, computed tomography comparison and pitfalls in imaging of upper urinary tract urothelial carcinoma. A recent study reported the high diagnostic accuracy of computed tomography urography with respect to T3 or higher stage tumors. To date, images that show a Tis–T2 stage have not been reported, but various studies are ongoing. Although magnetic resonance imaging has lower spatial resolution than computed tomography urography, magnetic resonance imaging can be carried out without radiation exposure or contrast agents. Magnetic resonance imaging also offers the unique ability of diffusion‐weighted imaging without contrast agent use. Some researchers reported that diffusion‐weighted imaging is useful not only for detecting lesions, but for predicting the T stage and tumor grade. We recommend the appropriate use of computed tomography and magnetic resonance while considering the limitations of each modality and the pitfalls in upper urinary tract urothelial carcinoma imaging.     

Diagnostic imaging for intracerebral hemorrhage

Magnetic resonance imaging (MRI) is an excellent tool for the diagnosis and evaluation of intracerebral hemorrhage with its unique specificity to hemoglobin degradation products in different stages. Computed tomography (CT) remains the diagnostic test of choice in the setting of acute intracerebral hemorrhage because of its exquisite sensitivity and specificity for small amounts of intracerebral hemorrhage (although there is emerging evidence that MRI may be as sensitive as CT). The effects of the biochemical evolution of intracerebral hemorrhage on the temporal MRI signal changes are described. This article discusses imaging features of the common causes of intracerebral hemorrhage.     

CT‐guided biopsy of breast lesions: When should it be considered?

Mammography, ultrasound, and magnetic resonance imaging (MRI) are the most commonly used modalities for interventional radiology procedures involving the breast. Computed tomography (CT) is rarely used for breast imaging yet it is able to detect breast lesions and can often provide safe and effective access to breast lesions. The aim of this study was to demonstrate situations in which CT should be considered as an alternative guidance method for the biopsy of breast lesions that are not accessible with conventional imaging modalities.     

Mielolipoma extraadrenal retroperitoneal

Extraadrenal myelolipomas are rare benign tumors and differentiating them from other soft tissue tumors containing fat can be difficult. A retroperitoneal myelolipoma adjacent to right renal helium is presented in this case-report. Initially oriented as liposarcoma, the final diagnosis was obtained after surgery. Computed tomography (CT), ultrasound (US) and magnetic resonance imaging (MRI) features may vary according to the major component of the tumor. MRI with fat suppression and opposed-phase imaging are the best imaging tools to demonstrate the adipose tissue. A histological confirmation may allow a better presurgical planification in most cases.     

Is there a role for magnetic resonance imaging in renal trauma?

BACKGROUND: Computed tomography (CT) has been the most informative imaging method in renal trauma. Despite the good sensitivity of magnetic resonance imaging (MRI) to the presence of hematoma, edema and ischemia, MRI has not been widely studied in patients with renal trauma. The present study was initiated to evaluate the role of MRI in patients with renal trauma. METHODS: Between June 1998 and September 1999, CT and MRI were prospectively performed on 12 patients who suffered from renal trauma and the results reviewed. RESULTS: The presence and size of perirenal hematoma could be detected by both CT and MRI. Magnetic resonance imaging could differentiate intrarenal hematoma from perirenal hematoma more accurately, and provided additional information about the hematoma as T1- and T2-weighted MRI were able to determine recent bleeding in the hematoma by regional differences in signal intensity. Magnetic resonance imaging clearly revealed renal fracture with non-viable fragment and detected focal renal laceration that was not detected on CT due to perirenal hematoma associated with renal infarction. However, although MRI had many advantages over CT, it had also major drawbacks, which were that it required longer imaging time and increased the cost. CONCLUSIONS: Magnetic resonance imaging may be useful in renal trauma. However, it is suggested that MRI should be limited to carefully selected patients, such as those with severe renal injury or equivocal findings on CT.     

Pancreatic tumors: role of imaging in the diagnosis, staging, and treatment

Because most patients with pancreatic cancer present with biliary obstruction, percutaneous transhepatic cholangiopancreatography (PTC) or endoscopic retrograde cholangiopancreatography (ERCP) is often performed first to relieve obstruction. Fine needle biopsy (FNA) provides a tissue diagnosis, but is often nondiagnostic due to sampling error. Computed tomography (CT) is the workhorse of oncology, but is poor at defining the nature of pancreatic lesions. Small primary tumors are often not visualized. Fast magnetic resonance imaging (MRI) techniques allowing dynamic imaging after IV gadolinium and new contrast agents allow better characterization of the lesions for patients having contraindications for IV CT contrast agents. Magnetic resonance cholangiopancreatography (MRCP) allows noninvasive visualization of the biliary tree. Endoscopic ultrasonography (EUS) allows evaluation of the detailed regional anatomy with the possibility of FNA. ¹⁸F-Fluorodexoglucose (FDG) is the most common tracer used in positron emission tomography (PET), and most malignant tumors, including pancreatic carcinoma, have increased FDG uptake compared with normal cells. This functional imaging does not replace but is complementary to morphological imaging. FDG PET is particularly helpful: (1) for the diagnosis in patients with suspected pancreatic cancer in whom CT fails to identify a mass, or those in whom FNAs are nondiagnostic; (2) for staging by detecting CT-occult metastases; (3) for detecting recurrence; and (4) for monitoring therapy. Limitations include false-positive inflammatory processes and false-negative carcinoma in patients with diabetes and hyperglycemia, and islet cell tumors.     

Nuclear medicine imaging in osteonecrosis of hip:Old and current concepts

Osteonecrosis(ON) is caused by inadequate blood supply leading to bone death, which results in the collapse of the architectural bony structure. Femoral head is the most common site involved in ON. Magnetic resonance imaging(MRI) is a commonly used imaging modality to detect early ON. When MRI is inconclusive, bone scan is helpful in detecting ON during early phase of the disease. As newer nuclear medicine equipment, like single photon emission computed tomography/computed tomography(CT) and positron emission tomography/CT, are emerging in medical science, we review the role of these imaging modalities in ON of femoral head.     

Imaging of the urinary tract: the role of CT and MRI

Computed tomography (CT) and magnetic resonance imaging (MRI) are increasingly valuable tools for assessing the urinary tract in adults and children. However, their imaging capabilities, while overlapping in some respects, should be considered as complementary, as each technique offers specific advantages and disadvantages both in actual inherent qualities of the technique and in specific patients and with a specific diagnostic question. The use of CT and MRI should therefore be tailored to the patient and the clinical question. For the scope of this article, the advantages and disadvantages of these techniques in children will be considered; different considerations will apply in adult practice.     

Penetrating abdominal aortic ulcers: case reports and review of the literature

Atherosclerotic abdominal aortic ulcers are uncommon in contrast to those of the thoracic aorta. They present with a variety of symptoms. Computed tomography (CT) scans and magnetic resonance imaging (MRI) are the methods of diagnosis. Treatment is made easier with the use of endovascular techniques, which have less mortality and morbidity than open repair. In this paper, we present three cases of penetrating aortic ulcers presenting with abdominal pain. In two of those cases, the diagnosis was made by MRI and missed by CT scan. We present a review of the literature.     

Stereotactic imaging for radiosurgery: localization accuracy of magnetic resonance imaging and positron emission tomography compared with computed tomography

Computed tomography (CT), magnetic resonance imaging (MRI), and positron emission tomography (PET) provide complementary information for treatment planning in stereotactic radiosurgery. We evaluated the localization accuracy of MRI and PET compared with CT. Two kinds of phantoms applicable to the Leksell G stereotactic skull frame (Elekta, Tokyo) were developed. Deviations of measured coordinates at target points (x = 50, 100, 150; y = 50, 100, 150) were determined on different axial planes (z = 30-140 for MRI and CT study and Z = 50-120 for PET and CT study). For MRI, the deviations were no more than 0.8 mm in each direction. For PET, the deviations were no more than 2.7 mm. For both imaging modalities studied, accuracy was at or below the imaging resolution (pixel size) and should be considered useful for clinical stereotactic planning purposes.     

Imaging of the hip joint. Computed tomography versus magnetic resonance imaging.

The authors reviewed the applications and limitations of computed tomography (CT) and magnetic resonance (MR) imaging in the assessment of the most common hip disorders. Magnetic resonance imaging is the most sensitive technique in detecting osteonecrosis of the femoral head. Magnetic resonance reflects the histologic changes associated with osteonecrosis very well, which may ultimately help to improve staging. Computed tomography can more accurately identify subchondral fractures than MR imaging and thus remains important for staging. In congenital dysplasia of the hip, the position of the nonossified femoral head in children less than six months of age can only be inferred by indirect signs on CT. Magnetic resonance imaging demonstrates the cartilaginous femoral head directly without ionizing radiation. Computed tomography remains the imaging modality of choice for evaluating fractures of the hip joint. In some patients, MR imaging demonstrates the fracture even when it is not apparent on radiography. In neoplasm, CT provides better assessment of calcification, ossification, and periosteal reaction than MR imaging. Magnetic resonance imaging, however, represents the most accurate imaging modality for evaluating intramedullary and soft-tissue extent of the tumor and identifying involvement of neurovascular bundles. Magnetic resonance imaging can also be used to monitor response to chemotherapy. In osteoarthrosis and rheumatoid arthritis of the hip, both CT and MR provide more detailed assessment of the severity of disease than conventional radiography because of their tomographic nature. Magnetic resonance imaging is unique in evaluating cartilage degeneration and loss, and in demonstrating soft-tissue alterations such as inflammatory synovial proliferation.     

Scimitar syndrome; report of a case

A 17-year-old woman with scimitar syndrome without an atrial septal defect was operated by intra-cardiac conduit repair. Computed tomography (CT) and magnetic resonance imaging (MRI) showed resolution images of anatomical findings of scimitar vein. Surgical procedures for the scimitar syndrome have varied according to the anatomic features presented in each case. The detection of precise anatomy of scimitar syndrome is important for determining the appropriate surgical procedure. Images of 3-dimensional (3-D) CT and MRI of scimitar syndrome were demonstrated.     

A case of pineoblastoma primary presenting a pineal hemorrhage causing obstructive hydrocephalus]

A 9-year-old female suddenly developed headache and nausea. Computed tomography (CT) revealed pineal mass lesion and obstructive hydrocephalus. One week after the onset, hydrocephalus spontaneously resolved. Magnetic resonance imaging (MRI) revealed that the mass was a subacute hematoma and that hydrocephalus had improved. Sequential MRI 4 months later revealed an enhanced lesion in the pineal region. Total removal of the tumor by the occipital transtentorial approach established the histopathological diagnosis of pineoblastoma.     

Modern imaging for liver metastases from colorectal tumors]

Cross-sectional imaging modalities such as ultrasound, computed tomography (CT), magnetic resonance imaging (MRI), and Positron emission tomography (PET)/CT have benefited from rapid technical advances in recent years. In patients with colorectal tumors, multislice CT is the standard technique for preoperative evaluation and follow-up. It is faster than single-slice helical CT and allows for excellent 3D imaging of liver anatomy and tumor volumetry. The most accurate technique for detecting and characterizing focal liver lesions is MRI using state-of-the-art scanners and liver-specific contrast agents and should be used for preoperative evaluation of all possible surgical candidates. Whole-body FDG-PET and PET/CT are most useful in the detection of extrahepatic disease and may alter clinical management in up to 20% of patients by detecting extrahepatic spread of disease.     

Diagnosis of intra-articular fracture of the head of the tibia. A prospective comparative study

Complete visualization of the joint surface is essential for correct assessment of tibial head fractures. Conventional tomography, computed tomography (CT), and magnetic resonance imaging (MRI) are compared in this prospective study. We examined 27 patients (19 suffering from B fractures and 8 from C fractures) from 1 January 1995 to 11 November 1998. Conventional tomography underestimated the fractures in 3 of the 19 cases of B fractures. Computed tomography underestimated two of these cases. MRI could not exactly depict the essential structures in three of the eight cases of C fractures because of edema and effusions. MRI identified complete cruciate ligament rupture in 6 of the 27 cases (18%) and 10 meniscal ruptures in 9 cases (33%: 6 medial meniscus, 4 lateral meniscus). Complete ruptures of the lateral collateral ligament were detected in five cases and medial collateral ligament ruptures in two cases. According to this, 63% of the patients suffered from relevant accompanying soft tissue injuries. The rate of soft tissue injuries increased up to 92% including the partial collateral ligament ruptures. Local hospital conditions permitting, X-ray-loaded conventional tomography should no longer be used in tibial head fractures. X-ray-free MRI is most efficient in cases of B fractures, which can in most cases be treated with a minimum of invasive techniques. Computed tomography is to be used in cases of C fractures that are regularly managed by open surgery accompanied by direct visualization of the inside of the knee joint.     

Advanced Renal Mass Imaging: Diffusion and Perfusion MRI

Computed tomography (CT) is considered the imaging modality of choice in evaluation of renal lesions. The advantages of magnetic resonance imaging (MRI) compared to CT include superior soft tissue contrast, avoidance of ionizing radiation and iodinated contrast media, and the possibility of performing functional and advanced imaging techniques such as diffusion-weighted (DWI) and perfusion–weighted imaging (PWI). Although the traditional role of MRI in the evaluation of renal mass is primarily that of a problem-solving tool, DWI and PWI are expanding the role of MRI in management of renal cell cancers. DWI and PWI have shown considerable promise not only in renal lesion detection and characterization as benign or malignant, but also in assessment of renal cell cancer subtype and nuclear grade. Furthermore, these techniques have the potential to assist with tailoring patient- and disease-specific management by providing surgical planning in patients with localized renal cell cancer and assessing treatment response in patients with advanced renal cell cancer undergoing targeted chemotherapy.