Gadolinium-enhanced dynamic MRI of the fractured carpal scaphoid: preliminary results

The aim of the present report was to evaluate the vascularity of fracture fragments of the fractured carpal scaphoid in the acute (< 4 weeks) and chronic (> 3 months) phases using a gadolinium-enhanced dynamic MRI sequence. Eight patients with acute scaphoid fractures, six patients with chronic scaphoid fractures, and three control patients without fractures were evaluated using a T1-weighted fast spoiled gradient recalled acquisition (fSPGR) sequence with gadolinium-DTPA enhancement (0.1 mmol/kg bodyweight). Signal intensity over time plots were obtained using region of interest measurements from both fracture fragments. Enhancement factors (EF) were then calculated from the plots. No enhancement of the scaphoid was seen in control subjects (EF: distal scaphoid pole 1.04 +/- 0.01, proximal pole 1.07 +/- 0.08). In acute fracture patients, enhancement of the distal pole was greater than that of the proximal in all cases but one in which the two poles enhanced in a similar fashion (EF: distal 1.99 +/- 0.77, proximal 1.43 +/- 0.99). In chronic fracture patients the enhancement pattern was reversed, as the proximal pole enhanced to a greater degree than the distal with the exception of one case where both poles enhanced equally (EF: distal 1.74 +/- 0.52, proximal 2.64 +/- 0.50). Using a two-tailed non-parametric Mann-Whitney U-test, the difference in enhancement of the proximal poles between the acute and chronic groups was found to be highly significant (P < 0.003). Dynamic contrast-enhanced (fSPGR) MRI demonstrates significant differences in the enhancement patterns of the scaphoid when chronic and acute fractures are compared.

Diagnostic equivalence of conventional and fast spin echo magnetic resonance imaging of the anterior cruciate ligament of the knee

Many techniques and pulse sequences have been devised for the assessment of the anterior cruclate ligament. The present study compares fast spin echo (FSE) imaging to conventional spin echo imaging at a field strength of 1.5 T in an effort to determine if these sequences are diagnostically equivalent. Where available, arthroscopy was also done. A total of 52 patients were imaged using both FSE and conventional spin echo sequences. Eight volunteers were used as controls. Arthroscopy was performed on 10 patients. The anterior cruciate ligament was assessed in a blinded fashion by three radiologists. The Kappa statistic was then used to determine the percentage agreement between FSE and conventional spin echo imaging. Fast spin echo sequencing demonstrated a sensitivity of 100%, a specificity of 94.8% and an accuracy of 96.3% when compared to arthroscopy. Conventional spin echo imaging and arthroscopy had a sensitivity of 100%, specificity of 84.6% and an accuracy of 88.9%. The remaining 34 patients who did not undergo arthroscopy were followed clinically because clinical and imaging findings were not suggestive of ACL tears. These demonstrated 72% agreement between FSE and conventional spin echo imaging using the Kappa statistic, with regards to calling ACL normal or having only a low-grade partial tear. Fast spin echo imaging produces images of the anterior cruciate ligament that have similar diagnostic accuracy to conventional spin echo images (P < 0.05) within a much shorter scan time. These results however, require further validation in a larger group, preferably with arthroscopic correlation.

Prostatic cryosurgery: use of MR imaging in evaluation of success and technical modifications

PURPOSE

To evaluate the usefulness of contrast material-enhanced magnetic resonance (MR) imaging in objective assessment of prostatic cryosurgery and the role of MR imaging in the modification of prostatic cryosurgical technique.

MATERIALS AND METHODS

Thirty-eight consecutive patients with localized (T1-3, N0, M0) prostatic adenocarcinoma treated with prostatic cryosurgery underwent MR imaging without contrast enhancement before cryosurgery and unenhanced and gadolinium-enhanced MR imaging within 1-3 weeks after cryosurgery. The first 20 patients also underwent MR imaging at 3 months after cryosurgery. MR imaging findings were correlated with those from transrectal ultrasound-directed prostatic staging biopsy.

RESULTS

Cryonecrotic prostate was identified as avascular regions characterized by absolute signal void on contrast-enhanced images. With progressive modification of cryosurgical technique, complete cryoablation of the prostate was achieved in the latter nine of the 38 patients. When cryoablation was considered complete according to MR imaging criteria, findings invariably correlated with those at biopsy, with no residual prostate tissue or tumor.

CONCLUSION

Gadolinium-enhanced MR imaging of the prostate after cryosurgery provides a highly accurate means of monitoring success. Objective MR imaging findings allow modifications to the technology and technique, resulting in optimal therapeutic results with prostatic cryosurgery.

THE FREQUENCY OF VENOUS THROMBOSIS IN CEMENTED AND NON-CEMENTED HIP ARTHROPLASTY

We randomised 250 patients undergoing unilateral, elective hip arthroplasty for osteoarthritis to receive either a cemented or a non-cemented Mallory Head prosthesis. Aspirin was used as prophylaxis against thromboembolism during the first half of the study and adjusted-dose warfarin during the second half. Postoperatively, all patients were asked to have bilateral venography and 80% agreed. All were evaluated clinically for pulmonary embolism.

There was no difference in the frequency of deep-venous thrombosis between the two groups (50% cemented v 47% non-cemented, p = 0.73; 95% CI of the difference −13.6% to 19.3%). Three of the 64 patients (5%) in whom venography had demonstrated isolated distal thrombi developed pulmonary emboli.

The frequency of venous thrombosis in cemented and non-cemented hip arthroplasty

We randomised 250 patients undergoing unilateral, elective hip arthroplasty for osteoarthritis to receive either a cemented or a non-cemented Mallory Head prosthesis. Aspirin was used as prophylaxis against thromboembolism during the first half of the study and adjusted-dose warfarin during the second half. Postoperatively, all patients were asked to have bilateral venography and 80% agreed. All were evaluated clinically for pulmonary embolism. There was no difference in the frequency of deep-venous thrombosis between the two groups (50% cemented nu 47% non-cemented, p = 0.73; 95% CI of the difference -13.6% to 19.3%). Three of the 64 patients (5%) in whom venography had demonstrated isolated distal thrombi developed pulmonary emboli.

Patellar tendinitis: MR imaging features, with suggested pathogenesis and proposed classification

PURPOSE

To characterize the magnetic resonance (MR) imaging features of patellar tendinitis.

MATERIALS AND METHODS

Fifteen patients with a clinical diagnosis of patellar tendinitis underwent gadolinium-enhanced MR imaging of the knee.

RESULTS

Grades of patellar abnormality, based on findings in the enthesial region at MR imaging, correlated with signs of increasing fibrovascular repair: grade 1 (n = 4), enhancing area adjacent to patellar apex, with marginal zone of intermediate signal intensity, and a patellar apical chondral-bone avulsion; grade 2 (n = 5), same signs as grade 1 damage but without avulsion; grade 3 (n = 6), homogeneous, nonenhancing area of intermediate signal intensity adjacent to the patellar apex seen on all images. Changes were most obvious posteriorly and involved the central and medial thirds of the tendon. Chronic injury to the medial retinaculum was a common associated finding.

CONCLUSION

Patellar tendinitis demonstrates a consistent spectrum of changes at MR imaging that can aid understanding of the origin and treatment of damage.

Anterior cruciate ligament tear: prospective evaluation of diagnostic accuracy of middle- and high-field-strength MR imaging at 1.5 and 0.5 T

PURPOSE

To compare the diagnostic efficacy of current-generation middle- and high-field-strength magnetic resonance (MR) imagers in the diagnosis of anterior cruciate ligament (ACL) tears.

MATERIALS AND METHODS

In 114 of 230 patients referred for knee imaging, MR imaging at 0.5 and 1.5 T was performed with identical sequences but with a slightly longer total imaging time and bandwidth optimization at 0.5 T. Radiologists were blinded to diagnosis and field strength. Sensitivity, specificity, and accuracy were determined, and ACL tear was confirmed by means of arthroscopy and pathology.

RESULTS

There was no difference between the field strengths in accuracy, sensitivity, or specificity for the diagnosis of ACL tears in 86 patients with disrupted ACLs and 28 patients with intact ACLs. Accuracy for all ACL tears was 90% at 0.5 T and 91% at 1.5 T. Similarly, there were no differences in diagnosis of meniscal tears (79 with, 149 without) or posterior cruciate ligament tears (seven with, 107 without).

CONCLUSION

Higher field strength does not confer higher accuracy in the diagnosis of ACL tears at MR imaging.

Magnetic resonance imaging evaluation of the rotator cuff tendons in the asymptomatic shoulder

Thirty shoulders in 20 volunteers (average age, 29 years; range, 17 to 49) with no shoulder symptoms or known abnormalities were scanned using magnetic resonance imaging. All scans were interpreted by one radiologist who was blinded to clinical data. Appearance of rotator cuff tendons on the images was graded. Grade 0 was normal, homogeneous low signal intensity structure. Grade 1 lesion was focal, linear, or diffuse intermediate signal through the tendon. Grade 2 lesion was high signal intensity within the tendon and less than full thickness. Grade 3 was high signal intensity through full thickness of the tendon. No supraspinatus or infraspinatus tendons were grade 0 (normal); all supraspinatus and infraspinatus tendons had grade 1 changes through the tendons; and 7 of 30 (23%) of the tendons had grade 2 changes. None of the 30 shoulders had grade 3 changes in the rotator cuff tendons. There is a wide array of abnormal magnetic resonance imaging signals in shoulders of young asymptomatic individuals, but they do not have full-thickness rotator cuff tears (grade 3 lesion). Nonenhanced magnetic resonance imaging may be of limited value in defining rotator cuff injury in a patient with shoulder pain unless a full-thickness rotator cuff tear is suspected clinically.

MR imaging field strength: prospective evaluation of the diagnostic accuracy of MR for diagnosis of multiple sclerosis at 0.5 and 1.5 T

PURPOSE

To compare the diagnostic efficacy of middle-field-strength and high-field-strength magnetic resonance (MR) imaging in diagnosis of multiple sclerosis.

MATERIALS AND METHODS

One hundred thirty-two patients with suspected multiple sclerosis underwent MR imaging at 0.5 and 1.5 T. Imaging parameters were identical except for band width optimization at middle field strength. Images were interpreted by radiologists expert in MR imaging who were blinded to diagnosis and field strength. The diagnosis of multiple sclerosis was made by experienced neurologists, and indeterminate cases and patients without clinical evidence of multiple sclerosis were followed up for 6 months to 1 year.

RESULTS

There was no difference in accuracy, sensitivity, or specificity between scanners in the diagnosis of multiple sclerosis or white matter disease. Equal numbers of lesions were detected at both field strengths in all parts of the brain. Image quality was always good or adequate at middle field strength.

CONCLUSION

Higher field strength does not confer higher accuracy in the diagnosis of multiple sclerosis with current-generation MR imagers.

Musculoskeletal infection: findings on magnetic resonance imaging

Magnetic resonance imaging (MRI) can provide considerable useful information in cases of musculoskeletal infection, in particular demonstrating the extent of involvement of soft tissues and medullary bone. Differentiation between infected tissue and abscess is also possible with MRI, especially if contrast agent is administered. MRI therefore serves as an adjunct to other imaging modalities, especially in complex cases. This review covers various manifestations of musculoskeletal infection as depicted with MRI.

The emerging role of magnetic resonance imaging in rheumatology

The role of magnetic resonance imaging (MRI) in imaging the central nervous system and in orthopedic radiology is now well accepted. Numerous applications of this technique also exist in the field of rheumatology, and it is anticipated that MRI will play an important part in the evaluation of treatments for the arthritides. In addition, MRI allows noninvasive investigation of other rheumatologic problems, such as avascular necrosis, tendon disorders and myopathy. This review outlines the current applications of MRI in rheumatologic practice.

Adamantinoma of the tibia: plain-film, computed tomography and magnetic resonance imaging appearance

The authors describe the computed tomography (CT) and magnetic resonance imaging (MRI) characteristics of adamantinoma of the tibia in a 29-year-old man. Adamantinoma is a rare, aggressive osteolytic lesion occurring primarily in the diaphyseal portion of long bones. Because of its rarity the MRI features have been infrequently reported. In this case MRI provided more accurate information about the extent and invasiveness of the tumour than either plain radiography or CT.

Imaging after arthroplasty

Arthroplasty is now an important and frequently performed orthopedic procedure. This article focuses on the imaging of abnormalities frequently encountered in patients who have undergone arthroplasty. The emphasis is on plain film analysis, although arthrography, computed tomography and nuclear medicine are also discussed. Among the problems illustrated are loosening of the prosthesis, component fatigue or failure, and infection. The authors recommend techniques to optimize imaging. Although most of the entities illustrated involve hip arthroplasty, the principles are valid for arthroplasty at other sites.

Self-contained, inflatable penile prosthesis: magnetic resonance appearance

The appearance of an inflatable penile prosthesis, visualized on a short tau inversion recovery sequence, is reported, in a patient who had magnetic resonance imaging for pelvic pain subsequent to radical cystoprostatectomy for bladder carcinoma. With suppression of adjacent fat signal, the prosthesis is well delineated from adjacent structures. The fluid-containing cylinders of the prosthesis are of very bright signal intensity, with the relief valve assembly of low signal intensity.

Magnetic resonance imaging of a giant nonfunctioning retroperitoneal paraganglioma

The authors describe the magnetic resonance imaging (MRI), computed tomographic, ultrasonographic and angiographic appearance of a giant nonfunctioning retroperitoneal paraganglioma. To their knowledge, the MRI appearance of a nonfunctioning paraganglioma has not been previously described. The MRI characteristics of the nonfunctioning tumour were similar to those of a functioning paraganglioma and included hyperintensity in T2-weighted images and intense enhancement after intravenous administration of contrast agent.

Sonography of ocular choroidal melanomas

Ocular choroidal melanomas lend themselves particularly well to evaluation by sonography. This essay illustrates the different appearances of ocular melanoma as depicted with sonographic imaging, including conventional gray-scale sonography and duplex Doppler, color flow Doppler, and three-dimensional display.

Hepatic pseudomass observed with computed tomography after direct injection of contrast agent into the portal vein

Hepatic pseudomasses have been described on both non-contrast and contrast-enhanced computed tomography (CT) scans, as well as on scans obtained by CT-arteriography and CT-portography. The authors describe a hepatic pseudomass that appeared in CT scans after direct injection of contrast material into the portal vein through an indwelling catheter.

Dynamic abdominal computed tomography: "top-down" compared with "bottom-up" imaging

Dynamic contrast-enhanced computed tomography (CT) of the liver is usually performed from the top down, and there is usually less opacification of the top slices than the more inferior slices. The authors reasoned that reversing the direction of scanning would allow more time for the parenchyma at the top of the liver to become enhanced and would result in better opacification of the parenchyma and the hepatic veins. To test this hypothesis they assigned 32 patients to either a "top-down" or a "bottom-up" group; each patient then underwent unenhanced and contrast-enhanced CT. The method of intravenous administration of contrast agent was identical in the two groups and consisted of rapid injection of 135 mL of iohexol by a power injector; scanning was initiated 30 seconds after the injection was started. Attenuation measurements were obtained at specified areas in the liver and in the hepatic and portal veins. The degree of enhancement was calculated at each site and was compared between groups. The upper portion of the liver showed significantly greater enhancement in the bottom-up sequence than in the top-down sequence (123% and 22% respectively; p < 0.01); the entire liver showed excellent enhancement in the bottom-up sequence. In addition, the hepatic veins showed significantly greater conspicuity in the bottom-up sequence (p < 0.01). The authors conclude that the dynamic bottom-up method yields excellent hepatic enhancement and vascular opacification and is therefore superior to the standard top-down method.

Three-dimensional sonographic reconstruction: techniques and diagnostic applications

In this review, we summarize the techniques of obtaining and reconstructing three-dimensional (3D) sonograms in a number of anatomic areas, catalog the clinical efforts at 3D sonography so far, and introduce more recent work in this area that takes advantage of the unique features of sonography. Although it is an active area of 3D imaging research, cardiac 3D imaging is not discussed because it has unique requirements stemming from the heart's anatomic inaccessibility and motion. Image analysis and display also are not covered, as no clear consensus has been reached about the usefulness of the large number of available methods.

Safety of outpatient peripheral angioplasty

PURPOSE

The safety of performing peripheral percutaneous angioplasty on an outpatient basis was studied.

MATERIALS AND METHODS

A retrospective cohort study was conducted of all peripheral angioplastic procedures performed at one institution during a 4-year period. The 350 procedures in 235 patients included 84 inpatient cases, 141 outpatient cases, and 125 1-day-care cases (ie, procedures performed in patients transferred from other hospitals).

RESULTS

The rates of major complications were 8.3% +/- 3.0 (mean +/- standard error) (n = 7) for inpatients. 5.0% +/- 1.8 (n = 7) for outpatients, and 5.6% +/- 2.1 (n = 7) for 1-day-care patients. Furthermore, 95% confidence intervals for the difference between complication rates were -10.3% and 3.5% for outpatient versus inpatient cases and -9.9% and 4.4% for 1-day-care versus inpatient cases.

CONCLUSION

The risk of a major complication resulting from peripheral angioplasty in appropriately selected outpatients is no greater than it is for patients admitted for overnight observation.

Intracavitary aspergilloma: transthoracic percutaneous injection of amphotericin gelatin solution

For aspergillomas in patients with fibrocavitary lung disease, surgery is often not recommended. Injection or lavage of the cavities with solutions of potassium iodide or antifungal agents has had varying success and requires repeated sessions because of nonretention of the therapeutic agent within the cavity. In three patients with four aspergillomas, the authors used fluoroscopic or computed tomographic (CT) guidance to inject amphotericin in gelatin as a liquid that solidifies within the cavity at body temperature. The patients were followed up with serial chest radiography or CT. The mixture was successfully instilled in every case. Three of the four aspergillomas completely resolved within 3 months or less, with no evidence of recurrence at follow-up of 6-18 months. The remaining aspergilloma decreased in size, but the patient needed pneumonectomy because of recurrent hemoptysis within 6 months of amphotericin injection. Transthoracic instillation of a liquid mixture of amphotericin and gelatin that solidifies rapidly at body temperature may be useful as a one-step treatment for aspergillomas.

Diagnosis of osteoid osteoma using STIR magnetic resonance imaging

Two patients with osteoid osteomas were evaluated with magnetic resonance imaging at 1.5 T using both conventional spin-echo (SE) and short TI inversion-recovery (STIR) sequences. On plain films the classic findings of a radiolucent nidus with a dense surrounding reactive zone of sclerosis were absent. The diagnosis was suspected on observing the presence of marked marrow oedema in the involved bone. Conventional SE images were unimpressive in detecting the bone marrow changes. Increased signal intensity indicating bone marrow oedema was striking on the STIR images and facilitated diagnosis. In cases of suspected osteoid osteoma which do not demonstrate the classic radiologic features, adding the STIR sequence to conventional SE magnetic resonance sequences to enhance detection of bone marrow change is recommended.

Excimer-laser-assisted angioplasty in chronic femoropopliteal occlusion: the significance of an intimal flap in predicting reocclusion

Angioplasty assisted by excimer laser was performed on 27 chronic femoropopliteal occlusions, ranging from 2 to 30 cm in length, in 26 patients. Twenty-one (78%) of the procedures were successful initially. Of these, 12 (57% [44% of the total]) remained patent at follow-up 3 months later. In seven of the nine cases of reocclusion observed after 3 months (78%) a large intimal flap resulting from the angioplasty-induced dissection could be identified in the postprocedure angiogram. The authors stress the possible importance of such an intimal flap in limiting the success of laser-assisted angioplasty of long femoropopliteal occlusions.

MR imaging of muscle and tender points in fibromyalgia

Fibromyalgia is a syndrome manifested by chronic, diffuse musculoskeletal aching and soreness, palpable muscle tender points, and other symptoms. Standardized clinical diagnostic criteria have recently been developed. Skeletal muscle has been postulated as the end organ in this disease. Biochemical, histologic, electromyographic, and conventional radiographic studies have demonstrated no definitive abnormality. This study sought to establish whether magnetic resonance (MR) imaging could demonstrate any abnormality in these patients. Eighteen patients were entered in the study, 14 of whom were able to complete their examinations. T1-weighted, T2-weighted, gradient-echo, and STIR (short-tau inversion-recovery) sequences were performed in all patients, with selected patients examined with T1-weighted, gadopentetate dimeglumine-enhanced sequences. The trapezius and suboccipital regions were imaged in patients who, clinically, had active fibromyalgia. No abnormalities could be detected. The authors conclude that the conventional MR imaging used in this study was unable to depict any primary skeletal muscle abnormality in fibromyalgia.

Producing picture-perfect posters

Scientific posters form an integral part of many radiology meetings. They provide the opportunity for interested parties to read the material at an individualized pace, to study the images in detail, and to return to the exhibit numerous times. Although the content of the poster is undoubtedly its most important component, the visual presentation of the material can enhance or detract from the clarity of the message. With the wide availability of sophisticated computer programs for desktop publishing (DTP), one can now create the poster on a computer monitor with full control of the form as well as the content. This process will result in a professional-appearing poster, yet still allow the author the opportunity to make innumerable revisions, as the poster is visualized in detail on the computer monitor before printing. Furthermore, this process is less expensive than the traditional method of typesetting individual sections separately and mounting them on cardboard for display. The purpose of this article is to present our approach to poster production using commercially available DTP computer programs.

Sonolucent peripancreatic masses: differential diagnosis and related imaging

The most common cause of a sonolucent mass in the epigastrium is a pancreatic pseudocyst; however, several other conditions can simulate a pseudocyst on ultrasonography (US) scans. This pictorial essay illustrates the spectrum of conditions that may present in this fashion and demonstrates the use of other imaging modalities, such as colour-flow and pulsed Doppler US, computed tomography, magnetic resonance imaging and angiography, in their evaluation.

The role of colour flow Doppler ultrasonography in the investigation of disease in the eye and orbit

Colour flow Doppler ultrasonography is a relatively new technique in which colour-encoded representations of flowing blood are imposed over a conventional grey-scale ultrasound image. This allows interrogation of a relatively large volume of tissue to determine the presence and direction of blood flow. The waveform tracings are then evaluated by means of conventional Doppler imaging. We demonstrate examples of normal vascular structures in the orbit and describe the application of this technique in the investigation of vascular disease, such as carotid-cavernous fistula and ischemic disease. The technique can also be used to evaluate ocular membranes and masses. Colour flow Doppler imaging promises to be an important advance in ophthalmic ultrasonography.

Tears of the medial collateral ligament: magnetic resonance imaging findings and associated injuries

For 23 patients with a surgically proven tear of the medial collateral ligament the findings from magnetic resonance imaging (MRI) of the knee were evaluated retrospectively. MRI revealed the tear in all cases, although when the injury was severe, distinguishing high-grade partial tears from complete tears was difficult. Physical examination had indicated a tear in 22 (96%) of the cases. A high prevalence of associated cruciate and meniscal injuries was seen (in 23 [100%] and 12 [52%] of the cases respectively). Tears of the fibular collateral ligament occurred in 13 (57%) of the patients and at least one bony infraction in 22 (96%); most of the infractions were in the lateral compartment. Infractions of the lateral femoral condyle were frequently geographic (in 14 [70%] of the 20 cases) or impacted (in 5 [25%]). The spectrum of injuries associated with tears of the medial collateral ligament was consistent with the findings of previous studies focusing on cruciate and meniscal abnormalities; the minor variations were likely due to the severity of valgus stress in this sample.

Leaking Baker's cyst detected by magnetic resonance imaging

Popliteal or Baker's cysts, often found incidentally during examination of the knee, are common. The authors report the magnetic resonance imaging (MRI) manifestations of a leaking Baker's cyst that initially presented as thrombophlebitis in a patient who had undergone reconstruction of the anterior cruciate ligament 4 months before; no cyst was present at the time of the surgery. Marked inflammatory changes apparent in the surrounding muscle and subcutaneous tissues were best appreciated in T2-weighted and fat-suppressed inversion recovery images. Although the results of ultrasonography suggested the diagnosis, they were not conclusive; MRI was a useful noninvasive adjunct in making the definitive diagnosis.

Intravenous administration of gadolinium in the evaluation of rheumatoid arthritis of the shoulder

The authors sought to determine the utility of intravenously administered gadolinium chelates in magnetic resonance imaging (MRI) of patients with rheumatoid arthritis of the shoulder. One shoulder was examined for each of 12 patients--6 men and 6 women, ranging in age from 48 to 71 (average 63) years--with well-established disease. The patients had had the disease for 1 to 25 (average 13) years. Static MRI was performed before and after infusion of gadolinium diethylenetriaminepentaacetic acid (Gd-DTPA) (0.1 mmol/kg body weight); T1-weighted or proton-density images (repetition time [TR] 600 to 1000 ms, echo time [TE] 15 to 30 ms) were obtained. Images obtained after enhancement were particularly useful in the differentiation of pannus from fluid and also allowed improved delineation of tears of the supraspinatus tendon. In addition, contrast-enhanced dynamic gradient-echo spoiled GRASS sequences (TR 50 ms, TE 11 ms, flip angle 70 degrees) were obtained for all patients; for these sequences the same slice was imaged repeatedly at 20-second intervals. The rate of increase of signal intensity in abnormal synovium varied from 0.64 to 5.83 (average 2.30, standard deviation [SD] 1.67) units/second; the enhancement factor ranged from 1.55 to 4.64 (average 2.63, SD 0.98). The authors conclude that for imaging the shoulder enhancement with Gd-DTPA allows improved distinction between synovial thickening and joint effusion and may improve assessment of the rotator cuff. The wide range in the rate of signal increase and total enhancement during dynamic imaging probably reflected heterogeneity in the study population.

Soft tissue sarcomas: a plea for proper management

Although soft tissue sarcomas are relatively uncommon, they often occur in young patients and if properly treated are often curable. Unfortunately, inappropriate approaches to biopsy before adequate staging may compromise a successful outcome. The roles of diagnostic imaging (particularly magnetic resonance imaging) in adequate preoperative evaluation and staging and the fundamental principles of surgical management are discussed.

Magnetic resonance imaging of reconstructed knee ligaments

Reconstruction of knee ligaments is now a common orthopedic procedure. Patients are frequently referred for magnetic resonance imaging (MRI) after later reinjury, and the ability to recognize normal reconstructed knee ligaments is therefore becoming increasingly important. This pictorial essay demonstrates various reconstructions of the cruciate and the collateral ligaments, as well as several abnormalities of these ligaments.

Ultrasonographic findings in the anterior segment of the eye obtained with a nondedicated unit

Many abnormalities of the anterior segment of the eye can be detected by ultrasonography (US), and associated anomalies of the posterior segment that are difficult to detect clinically may also be demonstrated by this modality. A total of 48 patients with ultrasonographically detectable abnormalities in the anterior segment were examined with real-time high-resolution US; 51 abnormalities were demonstrated. The most common problems were cataract (19 cases), intraocular lens implant (10), dislocated lens (9) and tumour (8). In addition, 23 abnormalities of the posterior segment of the eye were found. Six of the lesions in the posterior segment were obscured by those in the anterior segment and could be detected only by US.

Sciatic neuropathy associated with persistent sciatic artery

Persistent sciatic artery is a congenital vascular anomaly of the arterial supply to the lower extremity. Thrombosis, distal embolization, aneurysmal dilatation, and rupture of this vessel with compression of the sciatic nerve have been recorded. Although rare in occurrence, complications of persistent sciatic artery should be included in the differential diagnosis of sciatic neuropathy. We present a case of an acute sciatic neuropathy secondary to pseudoaneurysm formation of a persistent sciatic artery. We demonstrate the diagnostic usefulness of magnetic resonance imaging.

Peripancreatic fluid collections: vascular structures masquerading as pseudocysts

Five patients with splanchnic arterial aneurysms and one patient with a tortuous splenic vessel presented with peripancreatic masses that exhibited an anechoic portion in real-time ultrasonography (US) images; the masses were incorrectly diagnosed as pseudocysts. In two patients a vascular abnormality was suspected, and colour-flow Doppler and pulsed Doppler US were performed; these techniques showed the presence of pseudoaneurysms. In the other four patients the possibility of a pseudoaneurysm was not entertained until further studies had been performed. These results emphasize the need for colour-duplex US evaluation of all peripancreatic fluid collections during the initial US examination to avoid the misinterpretation of an aneurysm or a pseudoaneurysm as a simple or complex fluid collection and to prevent the potential disaster of performing biopsy, surgery or other interventions.

CT findings in patients with small-bowel transplants

Orthotopic small-bowel transplantation procedures are being performed increasingly often worldwide. CT plays an important role in both the preoperative assessment and the postoperative care of these patients. This pictorial essay serves to acquaint radiologists with the CT findings related to small-bowel transplantation.

Colour-flow Doppler imaging of a carotid-cavernous fistula

The authors describe a case of carotid-cavernous fistula evaluated with both conventional carotid angiography and colour-flow Doppler ultrasonography. The findings in the colour-flow Doppler images correlated well with those from angiography; in addition, Doppler imaging supplied extra information about the direction and the velocity of flow. After embolization, colour-flow Doppler imaging demonstrated a marked decrease in the flow. The authors conclude that colour-flow Doppler imaging may be useful for noninvasively detecting and evaluating a carotid-cavernous fistula, as well as for monitoring the patient's progress after therapy.

Tuberculosis of the odontoid bone: a rare but treatable cause of quadriplegia

Radiologic investigation plays an important role in the diagnosis and management of tuberculosis of the odontoid bone. Immediate confirmation of the condition by examination of tissue and surgery may save lives and reduce the morbidity rate substantially. When the clinical history is appropriate, a diagnosis of tuberculosis is strongly suggested by plain films of the cervical spine showing precervical swelling of the soft tissues, narrowing of the disk spaces and focal erosion of the bones and by computed tomography scans demonstrating details of the soft-tissue abnormality, focal bony erosion and sclerosis.

Subchondral bone infractions in acute ligamentous knee injuries demonstrated on bone scintigraphy and magnetic resonance imaging

Bone scintigraphy is used to detect radiographically silent fractures. Magnetic resonance imaging (MRI) is currently used to screen knee injuries for cartilage and ligament damage. MRI also delineates bone marrow and fractures. We investigated the bone scintigraphic findings in patients who had subchondral bone injuries demonstrated on MRI. Thirteen patients underwent MRI, three-phase bone scintigraphy with SPECT, and arthroscopic surgery after sustaining acute traumatic hemarthrosis of a knee. They all had clinically unsuspected subchondral bone injuries demonstrated on MRI with normal radiographs and normal overlying articular cartilage at arthroscopy, consistent with occult fractures. All showed focal bone repair on scintigraphy. Two of the 13 patients showed additional bone injuries only on bone scan. Two other patients scintigraphically showed focal bone repair at the medial femoral condyle due to avulsion of the medial collateral ligament. SPECT was easier to interpret than multi-view planar imaging. Bone scintigraphy confirms subchondral fractures demonstrated on MRI but also demonstrates ligament avulsion injuries and additional more subtle bone injuries.

Adenocarcinoma of the pancreatic ducts: comparative evaluation with CT and MR imaging at 1.5 T

A prospective comparison of computed tomography (CT) and magnetic resonance (MR) imaging at 1.5 T was performed in 50 patients with the suspected diagnosis of pancreatic carcinoma. CT scans were obtained before and after administration of contrast material in 41 of 50 patients (82%); 34 of 41 postcontrast scans (83%) were obtained with dynamic CT. MR images were interpreted without knowledge of the results of CT, ultrasound, cholangiography, or endoscopic retrograde cholangiopancreatography in 48 patients (96%). Surgical correlation of findings at CT and MR imaging was performed in 24 patients (48%) at laparotomy and in two patients (4%) at autopsy. On T1-weighted MR images, relatively diminished signal intensity of tumor compared with that of the adjacent pancreas was a consistent finding. MR imaging proved superior to CT in identification of pancreatic carcinoma (particularly in smaller intrapancreatic tumors), peripancreatic extension, vascular and portal vein invasion, and duodenal invasion. These results suggest that MR imaging of the pancreas is superior in many instances to CT in preoperative evaluation of pancreatic carcinoma.