Focal bone abnormality as a complication of ultrasound diathermy: a report of eight cases.

PURPOSE: To review the magnetic resonance (MR) imaging findings in eight patients who developed marrow lesions after undergoing physiotherapy with use of ultrasound diathermy. MATERIALS AND METHODS: The authors retrospectively reviewed the medical charts and MR images of eight patients (six women and two men aged 22-69 years) who received ultrasound diathermy treatment for a variety of soft tissue injuries involving primarily the knee, shoulder, and wrist. All patients underwent MR imaging without the use of intravenous gadolinium-based contrast material. The institutional review board approved the study, and the requirement to obtain informed consent was waived. RESULTS: MR imaging of all patients revealed subcortical rim or arc lesions with low signal intensity on T1-weighted images and high signal intensity on T2-weighted images, without involvement of the deeper aspect of the bone marrow. The imaging features of the lesions were similar to those of focal osteonecrosis. Follow-up MR imaging performed in three patients approximately 2-3 months after cessation of ultrasound therapy revealed resolution of the bone lesions. Symptoms resolved in all patients. CONCLUSION: This study demonstrated that ultrasound diathermy may produce an osseous injury. The abnormality itself was usually mild and transient, with apparent full recovery after termination of therapy.

Diagnostic performance of MR imaging in the assessment of subchondral fractures in avascular necrosis of the femoral head.

OBJECTIVE: A prospective study was conducted to determine the accuracy of routine magnetic resonance (MR) imaging in correctly identifying subchondral fracture in avascular necrosis of the femoral head without apparent focal collapse on standard radiographs. MATERIALS AND METHODS: Spiral computed tomography (CT) with coronal and sagittal reformations and routine MR imaging with spin-echo T1WI and fat-suppressed spin-echo T2WI coronal, axial, and sagittal images were performed in 28 hips of 25 patients (M/F = 20:5; age 16-76 years) suffering from early-stage avascular necrosis of the femoral head on standard radiographs. The MR images were reviewed by a musculoskeletal radiologist and a general radiologist in blinded fashion. Using CT as the standard of reference, the accuracy of MR imaging in diagnosing subchondral fractures in avascular necrosis was evaluated. RESULTS: When the diagnoses of the two readers were compared with each other, only 16 of the 28 diagnoses (57.5%) agreed. Seventeen of the 28 MR imaging readings (60.7%) made by the musculoskeletal radiologist and 15 of the 28 (53.5%) made by the general radiologist agreed with those of the CT standard. False-positive diagnosis (that is, diagnosis of fracture when no fracture could be seen on CT) was more common than false-negative diagnosis. CONCLUSIONS: The accuracy of routine MR imaging in the evaluation of subchondral fracture is not satisfactory. False-positive diagnosis is not uncommon. Interpretation of routine MR imaging readout should be guarded.

Dissection of arteria lusoria by transradial coronary catheterization: a rare complication evaluated by multidetector CT.

An aberrant right subclavian artery (arteria lusoria) arising from the descending thoracic aorta is an uncommon congenital variant that occurs in about 0.2-1.7% of the population. In such cases, the angular course of the arteria lusoria to the ascending aorta imposes difficulty in passing a guide wire to the ascending aorta during right transradial catheterization. Here, we present the first report of an iatrogenic dissection of arteria lusoria during transradial coronary angiography evaluated by multidetector computed tomography. Computed tomography is useful for assessing the severity and extension of the dissection to guide the clinical management of this complication.

MRI diagnosis of contracture of the gluteus maximus muscle.

OBJECTIVE: The objective of our study was to describe MRI features of contracture of the gluteus maximus muscle after providing a retrospective review of the MRI studies of 21 patients. CONCLUSION: Gluteal contracture manifests characteristic features on MRI, including an intramuscular fibrotic cord extending to the thickened distal tendon with atrophy of the gluteus maximus muscle and posteromedial displacement of the iliotibial tract. In advanced cases, medial retraction of the muscle and its tendon results in a depressed groove at the muscle-tendon junction and external rotation of the proximal femur. Clinical correlation and meticulous physical examination may confirm the MR diagnosis.

Normal bone mineral density in anteroposterior, lateral spine and hip of Chinese men in Taiwan: effect of age change, body weight and height.

BACKGROUND: The purpose of this study was to establish complete normative bone mineral density (BMD) values of Taiwanese men for anteroposterior, lateral spine, and hip. METHODS: Five-hundred and 69 healthy men (aged 20 to 88 years) were recruited to establish normal reference data of lumbar spine and hip, measured by a Hologic QDR 2000 bone densitometer. One-way analysis of variance was used to examine mean difference of BMD between different age groups. The effect of age change, body weight and height on BMD was determined by multivariate linear regression. RESULTS: The peak BMD values of most anatomic sites occurred in the age 20-30 group, and were 1.017, 0.862, 0.909, 0.860, 0.993 g/cm2 for anteroposterior spine, lateral spine, femoral neck, Ward's triangle, and total hip, respectively. The BMD values then steadily decreased with increase of age. After age 60-70, there was less age-related reduction of BMD values at the anteroposterior, lateral spines and Ward's triangle. By the 8th decade, the percentage losses in the anteroposterior spine, lateral spine, femoral neck, Ward's triangle, and total hip were 12%, 22%, 30%, 45%, and 22%, respectively. The BMD values correlated better with age and body weight than with body height at all anatomic sites. The body height was insignificant in predicting the BMD values at most anatomic sites. As compared with the normative BMD value provided by the Hologic Corporation, Chinese men had lower BMD value than Caucasian at most sites except Ward's triangle. At the anteroposterior spine, the values of Chinese and Japanese men were similar, whereas at the hip and its subregions, Chinese young male population had higher bone mineral density than Japanese. CONCLUSIONS: The data provided by this study may be used as normal reference values for Taiwanese men, instead of the values for Asians provided by the manufacturer.

Bilateral dorsal defect of patellae with patellar hypoplasia and patellofemoral malalignment.

Dorsal defect of the patella (DDP) is an uncommon but well-documented disease entity. We report a case of bilateral DDP with patellar hypoplasia and patello-femoral malalignment. Detailed imaging features including radiographic, magnetic resonance imaging, and computed arthrotomographic appearances, are described.

Metallic stenting for treatment of central venous obstruction in hemodialysis patients.

BACKGROUND: Central venous obstruction is a serious and common complication in hemodialysis patients. The recurrence rate is high after balloon dilation, while surgical repair is hazardous in these chronically ill patients. The aim of this study was to evaluate the efficacy of primary Wallstent placement for treatment of hemodialysis-related central venous obstructions. METHODS: Eighteen hemodialysis patients with symptomatic shunt dysfunction and arm swelling due to subclavian (n = 3) or innominate (n = 15) venous obstructions were treated at Kaohsiung Veterans General Hospital with primary Wallstent placement from November 1998 to August 2001. Technical success and complications were reported. Primary and secondary patency rates of stent and hemodialysis access were calculated by survival analysis with Kaplan-Meier method. RESULTS: A total of twenty-five Wallstents were deployed for central venous stenosis (n = 18) and occlusion (n = 7) in these 18 hemodialysis patients. The initial technical success rate was 100%. Fourteen episodes of re-obstruction developed during the observation period. Of them, seven episodes occurred within the stent, four episodes outside of but abutting to the peripheral end of the stent, and another three episodes of re-obstruction were attributed to delayed shortening of the Wallstent. Six of the 14 episodes were treated percutaneously with angioplasty alone, while seven episodes necessitated additional stent placement. No stent migration or other complications were encountered. Primary patency rates of stent and hemodialysis access at 3, 6, 12 and 18 months were 100 and 89%, 73 and 68%, 49 and 42%, and 16 and 0%, respectively. Secondary patency rates of stent and hemodialysis access each were both 100% after 3 months, 93 and 100% after 6 months, 85 and 91% after 12 months and, 68 and 72% after 24 months. CONCLUSIONS: Wallstents are safe to deploy, with excellent technical success for hemodialysis-related central venous obstructions. The Wallstent provides continued use of a hemodialysis access for a substantial period. However, repeated interventions may be necessary to maintain the patency.

Metallic stent placement for treating peripheral outflow lesions in native arteriovenous fistula hemodialysis patients after insufficient balloon dilatation.

OBJECTIVE: The purpose of this study was to report our experience with metallic stent placement in the peripheral outflow veins in native arteriovenous fistula (A-V fistula) hemodialysis patients after insufficient balloon dilatation. MATERIALS AND METHODS: During the past 4 years, 12 A-V fistula dialysis patients in our hospital underwent metallic stent placement in the peripheral outflow veins to restore vascular access. The indications for metallic stent placement in our study included (1) recoil stenosis of outflow vein in six patients; (2) outflow venous rupture in two patients and dissection in one patient; and (3) large residual adherent thrombus in outflow aneurysms in three patients with thrombosed (arteriovenous) access. Self-expandable Wallstent or Jostent (Jomed, Abbott Laboratories) of appropriate size (6-10 mm in diameter) was chosen for use in these patients. Kaplan-Meier survival analysis was used to calculate the access patency rates. RESULTS: Twelve patients received stents. Eleven patients (92%) underwent successful dialysis after the procedure. One patient experienced complications due to incorrect positioning of the stent at the anastomotic site, causing flow compromise. The primary patency (+/- standard error) of the vascular access at 3, 6, 12, and 24 months was 92% +/- 8%, 81% +/- 12%, 31% +/- 17%, and 31% +/- 17%, respectively. The secondary patency of the vascular access at 3 months was 92% +/- 8%, and 82% +/- 12% at 6, 12, and 24 months each. CONCLUSION: Metallic stent placement is safe and effective in treating peripheral venous lesions in native A-V fistula hemodialysis patients after unsatisfactory balloon dilatation.

Single-session alcohol-retention sclerotherapy for simple renal cysts: comparison of 2- and 4-hr retention techniques.

OBJECTIVE: The objectives of our study were to evaluate the feasibility of ethanol sclerotherapy in treating simple renal cysts with prolonged ethanol retention and to compare the therapeutic results of 2- and 4-hr retention techniques. MATERIALS AND METHODS: We retrospectively reviewed 36 renal cysts in 33 patients treated by ethanol sclerotherapy with a single-session single-injection technique during the past 6 years. After complete aspiration of the cystic fluid, 95% ethanol was injected into the cyst and was retained for 4 hr in 14 cysts (group 1) and for 2 hr in 22 cysts (group 2). The average maximal diameter and aspirated volume of the cysts were 8.3 cm and 223 mL in group 1 patients and 7.9 cm and 167 mL in group 2, respectively. The ablated cysts were followed up regularly by sonography, CT, or both at 3- to 6-month intervals for at least 1 year. The nonparametric Mann-Whitney U test was used to compare differences in characteristics, treatment results, and laboratory data of the subjects in the two groups. The level of statistical significance was set at a p value of less than 0.05. RESULTS: Technically, all the patients tolerated the procedures. One patient had gross hematuria 10 days after the procedure. She underwent surgical deroofing treatment and was excluded in the later statistical analysis. After sclerotherapy, 14 cysts disappeared completely and 16 cysts showed marked regression with residual maximal diameter of less than 3 cm. The overall volume reduction rate was 97.6% in all 35 cysts. The mean residual longest diameters and average volume reduction rates of the treated cysts were 1.9 cm and 97.9% in group 1 patients and 1.1 cm and 97.3% in group 2 patients, respectively, which showed no statistical significance of volume reduction rate with a p value 0.149. CONCLUSION: The single-session prolonged ethanol-retention technique is safe and efficacious for the treatment of renal cysts. There is no statistical difference in therapeutic efficacy between 2- and 4-hr ethanol-retention techniques.

Intraspinal posterior epidural cysts associated with Baastrup's disease: report of 10 patients.

OBJECTIVE: This study was performed to describe the association of posterocentral epidural cysts with interspinous bursal fluid in Baastrup's disease using MRI and interspinous bursography. CONCLUSION: Interspinous bursal fluid in Baastrup's disease can extend into the posterocentral epidural space and cause various degrees of central canal stenosis. Bursography alone or combined with CT allows documentation of abnormal communicating channels between the interspinous bursa and epidural cyst.

Restoration of thrombosed Brescia-Cimino dialysis fistulas by using percutaneous transluminal angioplasty.

PURPOSE: To evaluate the authors' experience with a technique for management of thrombosed Brescia-Cimino arteriovenous fistula. MATERIALS AND METHODS: Forty patients with 42 thrombosed arteriovenous fistulas were percutaneously treated. Thrombosis occurred within 24 hours of attempted angioplasty in five fistulas, between 24 and 72 hours in 27, and longer than 72 hours in 10. Thrombosed fistulas were approached in a retrograde fashion followed by direct balloon dilation with 5-8-mm balloon catheters. If retrograde catheterization failed to cross the arterial anastomosis, an antegrade puncture directly into the thrombosed drainage vein close to the anastomosis was performed with ultrasonographic guidance, as an aid to catheterize the arterial inflow. Thrombolytic therapy with infusion of urokinase directly into the thrombus was performed in selected patients with visible thrombus that had compromised blood flow in the partially restored vascular access. Postintervention primary and secondary patency was calculated by using Kaplan-Meier analysis. Patency rates between patients without and with urokinase infusion were examined by using the log-rank test. RESULTS: Anatomic success was achieved in 39 (93%) of 42 fistulas; and clinical patency, in 38 (90%) of 42 fistulas. Postintervention primary and secondary patencies (including initial technical failure) at 6, 12, and 18 months were 81% and 84%, 70% and 80%, and 63% and 80%, respectively. No significance of patency rate between patients without and with urokinase infusion was found (P =.912). Three patients died of unrelated causes at 1, 2, and 5 months after the procedures. No major complications were encountered. CONCLUSION: High anatomic success and excellent clinical patency can be achieved in the salvage of thrombosed arteriovenous fistulas. Percutaneous restoration of arteriovenous fistulas should be attempted before surgical recreation to optimize outcome in patients undergoing hemodialysis.