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.

Hepatic arterial infusion chemotherapy for advanced hepatocellular carcinoma by placing a temporary catheter via the subclavian route.

BACKGROUND: A permanent reservoir implantation is considered mandatory for hepatic arterial infusion chemotherapy (HAIC) of hepatocellular carcinoma (HCC). Since treatment sessions of HAIC may be limited for these end-staged patients, a simple alternative technique for this treatment is desirable. PURPOSE: To evaluate the feasibility of placing a temporary catheter for HAIC in advanced HCC patients. MATERIAL AND METHODS: 25 advanced HCC patients underwent HAIC with drugs delivered from a temporary catheter which was placed percutaneously by puncturing the left subclavian artery under ultrasound guidance. A course of chemotherapy consisted of five consecutive daily infusions of 5-fluorouracil, cisplatin, mitomycin C, and leucovorin. The catheter was removed on the 6th day. Therapy was repeated every 4-6 weeks with maximal number of courses of up to six. The total courses of HAIC in each patient, the catheter-placed-related complications, tumor response rate, and median survival of the patients were registered. RESULTS: A total of 77 courses of HAIC were performed with 100% technical success of catheter placement (1-6 courses in each patient, average 3.1 courses). The overall response rate was 20%, with complete response in two patients and partial response in three patients. Eleven (55%) of the 20 non-responders died within 5 months (mean HAIC, two courses). None of the patients experienced complications such as catheter occlusion, hepatic arterial thrombosis, cerebral infarction, or local infection. CONCLUSION: With fewer catheter-related complications, HAIC by temporary catheter placement via subclavian puncture could be a treatment option.

Single-session prolonged alcohol-retention sclerotherapy for large hepatic cysts.

OBJECTIVE: Our purpose was to evaluate the safety and therapeutic efficacy of single-session prolonged alcohol sclerotherapy in treating large hepatic cysts. A therapeutic comparison between 4-hour and 2-hour retention techniques was also studied. MATERIALS AND METHODS: Twenty-seven patients with 31 hepatic cysts were enrolled in this study. Seventeen patients (18 cysts) were treated by alcohol retention for 4 hours (group 1) and 10 patients (13 cysts) for 2 hours (group 2). The mean diameter of the hepatic cysts was 12.4 cm (range, 8-23 cm) with a comparable size range in each group. The sclerosing agent used was 95% alcohol, and the maximum amount was limited to 200 mL. Patients changed position and vital signs were monitored every 10-15 minutes. The blood alcohol concentrations were checked hourly for 5 consecutive hours in the initial nine patients. The nonparametric Mann-Whitney U test was used to compare the difference in characteristics and treatment results of the subjects between these two groups. The level of statistical significance was set at a p value of less than 0.05. RESULTS: All but one patient in group 2 tolerated the entire course of sclerotherapy. The mean aspirated volume and mean injected alcohol volume of the hepatic cysts were 730 mL and 138.3 mL, respectively, in group 1 patients, and 931 mL and 139 mL, respectively, in group 2 patients. The mean maximum blood alcohol concentration was 128.2 mg/dL (range, 60-199 mg/dL) at 3-4 hours after alcohol instillation. The mean posttherapy residual cystic diameter was 2.5 cm (range, 0-6 cm), with an average volume reduction rate of 98.3% and 97.7%, respectively, for patients in group 1 and group 2 after a mean follow-up period of 29.6 months (9-59 months). No statistical differences of the mean reduction rate between the two groups were noted. CONCLUSION: Long retention of the alcohol in a single-injection technique is safe and effective. Two-hour alcohol retention has a comparable efficacy to that of 4-hour retention.

Percutaneous endovascular repair of a ureteroarterial fistula with a stent graft.

Ureteroarterial fistula is a rare but life-threatening cause of hematuria. The predisposing factors of a ureteroarterial fistula includes pelvic exenteration, radiation therapy, infection, primary vascular disease, vascular reconstructive surgery, and indwelling ureteral catheters or stents. We report a case of ureteroarterial fistula between the right ureter and a pseudoaneurysm originating from the right proximal external iliac artery in a female patient presenting with intermittent massive hematuria. She had previously undergone an operation for cervical cancer, radiation therapy, and ureteral stent placement. She was treated successfully by percutaneous endovascular stent graft placement to exclude the pseudoaneurysm. Percutaneous stent graft placement appears to be an effective and safe therapeutic alternative in the treatment of ureteroarterial fistula.

Temporal correlation-based dynamic contrast-enhanced MR imaging improves assessment of complex pulmonary circulation in congenital heart disease.

A temporal correlation (TC) mapping method is proposed to help bolus chasing during dynamic contrast-enhanced (DCE) MRI of complex pulmonary circulation (CPC) in patients with congenital heart disease. DCE-MRI was performed on five healthy male subjects (23-24 years old) and 25 patients (nine males and 16 females, 0.25-44 years old), and TC maps were generated by performing pixel-based computation of cross-correlations to the pulmonary artery with a series of time shifts in all subjects. Qualitative and quantitative evaluations were performed in comparison with original DCE images. TC maps exhibited a better signal-to-noise ratio (SNR) by factors of 4.3 and 1.3 in the lung parenchyma, pulmonary veins, and superior artery/vein; a better intraparenchymal contrast-to-noise ratio (CNR) by factors of 1.5-5.4; and a significantly higher conspicuity in all regions except the pulmonary arteries when graded with a five-point score. TC maps evaluated by two experienced clinicians significantly added relevant information (P<0.001), and in some cases affected the final diagnosis. We conclude that TC maps facilitate bolus chasing for DCE-MRI by reducing recirculation effects and interframe fluctuations, and hence complements morphological imaging of CPC in patients with complex congenital heart disease.

Diffusion tensor magnetic resonance imaging mapping the fiber architecture remodeling in human myocardium after infarction: correlation with viability and wall motion.

BACKGROUND: Diffusion tensor magnetic resonance imaging (DT-MRI) provides a means for nondestructive characterization of myocardial architecture. We used DT-MRI to investigate changes in direction-dependent water diffusivity to reflect alterations in tissue integrity (trace apparent diffusion coefficients [ADCs] and fractional anisotropy [FA]), as well as indicators of remodeling of fiber helix angles, in patients after myocardial infarction. METHODS AND RESULTS: Thirty-seven patients (35 men, 2 women; median age, 59) after acute myocardial infarction (median interval from onset, 26 days) were enrolled. DT-MRI was performed at the midventricular level to measure trace ADC, FA, and helix angles of myofibers. Helix angles were grouped into left-handed helical fibers, circumferential fibers, and right-handed helical fibers. Measurements were correlated with viability and regional wall motion assessed by contrast-delay-enhancement and cine MRI, respectively. The infarct zone showed significantly increased trace ADC and decreased FA than the remote zone. The percentage of left-handed helical fibers increased from the remote zone (mean +/- SD, 13.3 +/- 5.8%) to the adjacent zone (19.2 +/- 9.7%) and infarct zone (25.8 +/- 18.4%) (MANOVA, P = 0.004). The percentage of right-handed helical fibers decreased from the remote zone (35.0 +/- 9.0%) to the adjacent zone (25.5 +/- 11.5%) and infarct zone (15.9 +/- 9.2%) (P < 0.001). Multiple linear regression showed that the percentage of left-handed helical fibers of the infarct zone was the strongest correlate of infarct size and predictor of ejection fraction. CONCLUSIONS: In vivo DT-MRI of postinfarct myocardium revealed a significant increase in trace ADC and a decrease in FA, indicating altered tissue integrity. The redistribution of fiber architecture correlated with infarct size and left ventricular function. This technique may help us understand structural correlates of functional remodeling after infarction.

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.

Metallic stent placement in hemodialysis graft patients after insufficient balloon dilation.

OBJECTIVE: We wanted to report our experience of metallic stent placement after insufficient balloon dilation in graft hemodialysis patients. MATERIALS AND METHODS: Twenty-three patients (13 loop grafts in the forearm and 10 straight grafts in the upper arm) underwent metallic stent placement due to insufficient flow after urokinase thrombolysis and balloon dilation. The indications for metallic stent deployment included 1) recoil and/or kinked venous stenosis in 21 patients (venous anastomosis: 17 patients, peripheral outflow vein: four patients); and 2) major vascular rupture in two patients. Metallic stents 8-10 mm in diameter and 40-80 mm in length were used. Of them, eight stents were deployed across the elbow crease. Access patency was determined by clinical follow-up and the overall rates were calculated by Kaplan-Meier survival analysis. RESULTS: No procedure-related complications (stent fracture or central migration) were encountered except for a delayed Wallstent shortening/migration at the venous anastomosis, which resulted in early access failure. The overall primary and secondary patency rates (+/-standard error) of all the vascular accesses in our 23 patients at 3, 6, 12 and 24 months were 69%+/-9 and 88%+/-6, 41%+/-10 and 88%+/-6, 30%+/-10 and 77%+/-10, and 12%+/-8 and 61%+/-13, respectively. For the forearm and upper-arm grafts, the primary and secondary patency rates were 51%+/-16 and 86%+/-13 vs 45%+/-15 and 73%+/-13 at 6 months, and 25%+/-15 and 71%+/-17 vs 23%+/-17 and 73%+/-13 at 12 months (p = .346 and .224), respectively. CONCLUSION: Metallic stent placement is a safe and effective means for treating peripheral venous lesions in dialysis graft patients after insufficient balloon dilation. No statistically difference in the patency rates between the forearm and upper-arm patient groups was seen.

Percutaneous stent-graft repair of a mycotic pulmonary artery pseudoaneurysm.

Ruptured mycotic pulmonary pseudoaneurysm is a lethal complication. Emergent surgical repair is usually recommended, but still associated with a high mortality rate. We present a patient in whom mycotic pulmonary pseudoaneurysm was a complication after surgical lobectomy 2 weeks earlier. This patient had suffered from repeated massive hemoptysis. After emergent surgical repair of the ruptured pulmonary artery stump, another episode of massive hemorrhage occurred. The pulmonary arteriogram revealed a segmental stenosis and a large, wide-necked, lobulated pseudoaneurysm at the left proximal pulmonary artery. We deployed a balloon-expandable stent-graft (48 mm in length mounted on a 12 mm x 40 mm angioplasty balloon) across the stenotic segment and the neck of the pulmonary pseudoaneurysm. Hemostasis was achieved immediately and, under a 4-week antibiotic treatment, patient was transferred to a local hospital for medical care. This case report demonstrates the benefit of minimally invasive endovascular therapy in a critically ill patient. A literature review of the etiology and management of mycotic pulmonary pseudoaneurysm is included.

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.

Safety and accuracy of multidetector row computed tomography for early assessment of residual stenosis of the infarct-related artery and the number of diseased vessels after acute myocardial infarction.

BACKGROUND: Recent studies reveal that contrast-enhanced multidetector row computed tomography (MDCT) is a promising technique for noninvasive visualization of coronary artery stenoses. We investigated the safety and accuracy of MDCT for early assessment of the severity of residual stenosis of the infarct-related artery (IRA) and the number of diseased vessels in patients after acute myocardial infarction (AMI). METHODS AND RESULTS: Of 146 AMI cases admitted, 72 fit with criteria and underwent 16-slice MDCT (4 +/- 2 days after AMI) with beta-blockers. There were no complications except 1 patient who had from complete atrioventricular block. Results were compared with conventional coronary angiography (CCA) within 3 days. In 55 (73.3%) of 72 patients, all arteries were assessable. In total, the number of assessable arteries was 253 (87.8%), and 35 (12.2%) vessels were nonassessable, mostly because of motion artifacts and extensive calcification. Overall, 84 of the 115 lesions (> or = 50% lumen reduction) were correctly detected by MDCT (sensitivity 73.0%). The accuracy in classifying patients with nonsignificant, single-, or multiple-vessel diseases was 79.1%. The accuracy for residual lesions with >50% stenosis of IRA was 87.5%. There was a good correlation regarding the severity of residual stenosis of the IRA (0%, 1%-49%, 50%-89%, 90%-99%, or occlusion) between MDCT and CCA (Spearman correlation 0.94, P < .001). Lesions with 90% to 99% or occlusion of the IRA were accurately detected or ruled out in 31 of 36 cases (86.1%). CONCLUSIONS: With appropriate protocol, MDCT is safe and accurate in assessing the severity of IRA and the number of diseased vessels during the first week after AMI. It has the potential to provide triage for early management of patients after AMI.

Multi-detector row computed tomography angiography in diagnosing spinal dural arteriovenous fistula: initial experience.

BACKGROUND AND PURPOSE: Multi-detector computed tomographic (MDCT) angiography is a recently developed imaging technique that can study small vessels such as medullary arteries and veins. The purpose of this study was to evaluate MDCT angiography in diagnosing SDAVF. METHODS: Eight patients with initial magnetic resonance imaging (MRI) and clinical findings suggestive of spinal dural arteriovenous fistula (SDAVF) and 8 control subjects underwent MDCT angiography. Both MDCT angiography and catheter angiography were performed within 5 days in patients with SDAVFs. The results of MDCT angiography in patients with SDAVFs were compared with those of catheter angiography. RESULTS: MDCT angiography detected engorged perimedullary draining veins and correctly localized the fistula of the SDAVFs, and correlated well with catheter angiography. Fistula was at the thoracic level in 7 patients, and sacral level in 1 patient. MDCT angiography did not visualize the engorged perimedullary venous plexus in the control group. CONCLUSIONS: MDCT angiography correlated well with catheter angiography in diagnosing SDAVFs. It might play a role in shortening the length of the catheter angiography in diagnosing this disease.

CT voiding urethrography and virtual urethroscopy: preliminary study with 16-MDCT.

OBJECTIVE: The purpose of this study was to demonstrate CT voiding urethrography and CT virtual urethroscopy. Fourteen CT voiding urethrography examinations on 13 men (mean age, 30 years) were prospectively performed with 16-MDCT. The clinical diagnoses of those patients included urethral injury, urethral stricture, and hypospadia. The CT voiding urethrogram was obtained with transverse CT of the voiding, contrast-filled urethra and display of 2D multiplanar and 3D virtual images. CONCLUSION: The full urethral structure was clearly shown by CT voiding urethrography and virtual urethroscopy in all patients. The results of CT voiding urethrography and conventional methods correlated closely with the urethral diseases being imaged.

Detection of subarachnoid hemorrhage at acute and subacute/chronic stages: comparison of four magnetic resonance imaging pulse sequences and computed tomography.

BACKGROUND: Acute subarachnoid hemorrhage (SAH) has traditionally been diagnosed by computed tomography (CT); however, fluid-attenuated inversion recovery (FLAIR) is a magnetic resonance imaging (MRI) modality currently used to detect acute SAH. CT is insensitive in the detection of subacute or chronic SAH. The purpose of this study was to compare 4 MRI pulse sequences and CT in the detection of SAH in acute and subacute-to-chronic stages. METHODS: From 2001-2003, we collected data for 22 patients (12 men and 10 women, aged 35-80 years) with SAH due to ruptured aneurysm (n = 11), trauma (3), or unknown origin (8). All patients underwent MRI and CT examination, with an interval of less than 12 hours between the 2 procedures. We divided patients into 2 groups according to the time from symptom onset to MRI evaluation: patients with MRI performed < or = 5 days post-ictus had acute-stage illness, whereas patients with MRI performed from day 6-30 post-ictus had a subacute-to-chronic condition. MRI (1.5-T) pulse sequences comprised spin-echo T1-weighted, fast spin-echo T2-weighted, FLAIR, and gradient-echo (GE) T2*-weighted images. RESULTS: In the acute-stage group, SAH was seen as an area of high signal intensity compared with surrounding cerebrospinal fluid in 36.4% of cases on T1-weighted images, and in 100% on FLAIR images; low signal intensities were seen in 18.2% of cases on T2-weighted images, and in 90.9% on GE T2*-weighted images. High-attenuated SAH was seen on CT in 90.9% of cases. FLAIR (p = 0.008), GE T2*-weighted images (p = 0.012) and CT images (p = 0.012) were all statistically significant indicators of acute SAH. In the subacute/chronic-stage group, SAH was detected on T1-weighted images (36.4% of cases), FLAIR (33.3%), T2-weighted images (9.1%), GE T2*-weighted images (100%), and CT (45.5%). GE T2*-weighted images were significantly superior (p = 0.001) to other MRI pulse sequences and CT as indicators of subacute-to-chronic SAH. CONCLUSION: FLAIR and GE T2* MRI pulse sequences, and CT scans, are all statistically significant indicators of acute SAH. GE T2*-weighted images are statistically significant indicators of subacute-to-chronic SAH, whereas other MRI pulse sequences, and CT scans, are not.

Intra-abdominal gout mimicking pelvic abscess.

Gout is the most common crystal-induced arthritis. Gouty tophi typically deposit in the extremities, especially toes and fingers. We present an unusual case of intrapelvic tophaceous gout in a patient suffering from chronic gouty arthritis. CT and MRI of the abdomen and pelvic cavity disclosed calcified gouty tophi around both hips, and a cystic lesion with peripheral enhancement in the pelvic cavity along the course of the iliopsoas muscle. The intra-abdominal tophus mimicked pelvic abscess.

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.

The feasibility of low-dose CT for pulmonary metastasis in patients with primary gynecologic malignancy.

PURPOSE: To assess the feasibility of low-dose CT (LDCT) in the detection of pulmonary metastases in patients with primary gynecologic malignancies and also to compare the performance of chest digital radiography (DR) and LDCT for their delectability of pulmonary metastases, with use of standard-dose CT (SDCT) as the reference standard. MATERIALS AND METHODS: Thirty female patients with primary gynecologic malignancies (age range, 20-76 years; mean age, 50 years) underwent DR, noncontrast LDCT and contrast-enhanced SDCT, which were performed within an interval of 2 weeks. We used lung nodule, mediastinal lymphadenopathy (>10 mm in the short axis) and pleural changes (including effusion, irregular thickening, or nodularity) as the cardinal imaging findings of lung metastases. A five-point scoring system was designed to indicate the probability of lung metastasis from primary gynecologic malignancies. The five-point scores of DR, LDCT, and SDCT were analyzed by receiver operating characteristic (ROC) curve. RESULTS: SDCT probability scores of +2 and -2 were set to indicate true positive and true negative for pulmonary nodule, mediastinal lymphadenopathy, and pleural effusion, respectively. All the areas under the ROC curve of LDCT appeared to be larger than those of DR[pulmonary nodule: 0.96 [95% confidence interval (CI): 0.92-1.01] vs. 0.74 [95% CI: 0.57-0.91], 0.82 [95% CI: 0.70-0.95] vs. 0.61 [95% CI: 0.50-0.77]; mediastinal lymphadenopathy: 0.98 [95% CI: 0.93-1.03] vs. 0.90 [95% CI: 0.79-1.01], 0.94 [95% CI: 0.82-1.06] vs. 0.66 [95% CI: 0.44-0.88]; and pleural effusion: 0.98 [95% CI: 0.93-1.03] vs. 0.56 [95% CI: 0.29-0.82], 0.90 [95% CI: 0.74-1.05] vs. 0.46 [95% CI: 0.23-0.68]]. CONCLUSION: The performance of LDCT were comparable to those of SDCT and superior to those of DR for detection of pulmonary nodule, mediastinal lymphadenopathy, and pleural effusion. By using LDCT, there was no need of intravenous contrast injection and less radiation exposure. We propose a protocol including standard-dose abdominal CT and low-dose chest CT for the initial and follow-up stagings of primary gynecologic malignancy. The use of chest DR is unnecessary.

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.

Posterior reversible encephalopathy syndrome: magnetic resonance imaging and diffusion-weighted imaging in 12 cases.

Posterior reversible encephalopathy syndrome (PRES) is a potentially devastating neurologic syndrome, but timely treatment may lead to complete reversal of the disease course. We reviewed 12 cases of PRES and describe the clinical history and imaging findings, including conventional magnetic resonance imaging (MRI), diffusion-weighted imaging (DWI), and calculated apparent diffusion coefficient (ADC) maps, used to establish the diagnosis of PRES. Three male and nine female patients aged between 11 and 70 years (mean, 37 years) with clinical and imaging findings consistent with PRES were enrolled in the study. All patients had undergone conventional MRI and 10 had undergone additional DWI studies. Ten patients had follow-up MRI studies. DWI was performed using a 1.5T system with a single-shot spin-echo echoplanar pulse sequence. Initial and follow-up neuroimaging and clinical history were reviewed. Lesions were almost always present over the posterior circulation, mainly the parieto-occipital region, affecting primarily the white matter. The anterior circulation region, brainstem, cerebellum, deep cerebral white matter, and thalamus were also involved in five cases. Conventional MRI revealed hyperintensity on T2-weighted and fluid-attenuated inversion recovery images. DWI showed isointensity and increased signal intensity on ADC values in all cases, indicating vasogenic edema. Clinical and MRI follow-up showed that the symptoms and radiologic abnormalities could be reversed after appropriate treatment of the causes of PRES in most patients (9 of 10). In one patient, the ADC value was lower on follow-up images, indicating cytotoxic edema with ischemic infarct. DWI was a useful complement to MRI in the diagnosis of PRES.