Non-Infectious Ischiogluteal Bursitis: MRI Findings

Objective

We wished to report on the MRI findings of non-infectious ischiogluteal bursitis.

Materials and Methods

The MRI findings of 17 confirmed cases of non-infectious ischiogluteal bursitis were analyzed: four out of the 17 cases were confirmed with surgery, and the remaining 13 cases were confirmed with MRI plus the clinical data.

Results

The enlarged bursae were located deep to the gluteus muscles and postero-inferior to the ischial tuberosity. The superior ends of the bursal sacs abutted to the infero-medial aspect of the ischial tuberosity. The signal intensity within the enlarged bursa on T1-weighted image (WI) was hypo-intense in three cases (3/17, 17.6%), iso-intense in 10 cases (10/17, 58.9%), and hyper-intense in four cases (4/17, 23.5%) in comparison to that of surrounding muscles. The bursal sac appeared homogeneous in 13 patients (13/17, 76.5%) and heterogeneous in the remaining four patients (4/17, 23.5%) on T1-WI. On T2-WI, the bursa was hyper-intense in all cases (17/17, 100%); it was heterogeneous in 10 cases and homogeneous in seven cases. The heterogeneity was variable depending on the degree of the blood-fluid levels and the septae within the bursae. With contrast enhancement, the inner wall of the bursae was smooth (5/17 cases), and irregular (12/17 cases) because of the synovial proliferation and septation.

Conclusion

Ischiogluteal bursitis can be diagnosed with MRI by its characteristic location and cystic appearance.     

Differentiation of mediastinal FDG uptake observed in patients with non-thoracic tumours

In regions with a high prevalence of granulomatous diseases, benign inflammatory fluorine-18 fluorodeoxyglucose (FDG) uptake in the mediastinum is frequently observed even in healthy subjects. We examined parameters of mediastinal FDG uptake to determine whether they can differentiate malignancy from benign lesions. Seventy patients with non-thoracic tumours who had mediastinal uptake on FDG positron emission tomography (PET) were included (33 males, 37 females; age 57.5±16.9 years; 168 lymph nodes). Determination of metastasis was confirmed by biopsy or computed tomography (CT) follow-up over 12 months (metastasis, 29; benign lesions, 41). No significant difference between the metastasis group and the benign group was found in terms of residual disease in the primary site (48% vs 46%), lung invasion (29% vs 20%), number of sites of uptake (2.3 vs 2.4), smoking history (30.3% vs 46.3%) or bilateral uptake (52% vs 54%). Maximal standardised uptake values (SUVs) in the mediastinal metastasis group were higher (4.9±1.8) than those in the benign group (2.5±0.9) (P<0.05). Using 3.4 as a cut-off value for maximal SUV, a sensitivity of 86% and a specificity of 85% were achieved (AUC=0.917). Maximal SUV showed better predictive value than lymph node size measured on chest CT (P<0.05). In 8 of 51 normal subjects who underwent FDG PET as a routine check-up, mediastinal FDG uptake was observed. Maximal SUV in normal subjects was 2.5±0.8, which was similar to that in the benign group. In conclusion, maximal SUV was identified as a significant parameter for determining whether mediastinal FDG uptake represents malignant metastasis. When maximal SUV exceeded 3.4, the metastasis rate was high regardless of lymph node size.     

Application of a pressure-relieving air compliance chamber in a single-pulsatile extracorporeal life support system: an experimental study

Nonpulsatile blood pumps are mainly used in extracorporeal life support systems. Although pulsating blood flow is known to be physiological, a pulsatile pump is not commonly applied in a circuit with a membrane oxygenator because of damage to the blood cells. The hypothesis that the placement of a pressure-relieving compliance chamber in a circuit might reduce blood cell trauma was tested. An extracorporeal life support circuit was constructed in an acute lung injury model of dogs by oleic acid infusion. The animals were divided into three groups. In group I (n = 6) a nonpulsatile centrifugal pump was used as a control. In group II (n = 4) a single-pulsatile pump was used, and in group III (n = 6) a single-pulsatile pump equipped with a compliance chamber was used. Pump flow was maintained at 1.8-2.0 L/min for 2 h. Hemodynamics and blood gas analyses indicated that the pulsatile groups II and III had better results than the nonpulsatile group I. The plasma-free hemoglobin level, which indicates blood cell trauma, was the lowest in group I and the highest in group II but was significantly decreased in group III. A pressure-relieving compliance chamber could significantly reduce high circuit pressures and blood cell trauma.     

Combined Therapy of Radiofrequency Ablation and Ethanol Injection of Rabbit Liver: An <Emphasis Type="Italic">In Vivo</Emphasis> Feasibility Study

Our purpose was to compare the effects of percutaneous radiofrequency ablation (RFA) combined with percutaneous ethanol injection (PEI) on the extent of ablation in in vivo rabbit liver tissue as compared with either therapy alone. Twenty-two New Zealand white rabbits were included in this study and allocated into three groups: group A: conventional RFA (n = 6); group B: PEI (n = 6); group C: combined RFA and PEI (n = 10). For combined RFA and PEI, under ultrasound guidance, 1 mL of absolute ethanol was injected into the target area of the liver parenchyma through a 21-gauge Chiba needle before performing RFA. RFA was performed using a 17- gauge internally cooled electrode with 1-cm active tip, and RF energy (30 W) was applied for 3 minutes, with or without ethanol injection. After RFA or PEI, contrast-enhanced computed tomography and CT-pathologic correlation were performed. The short- axis and long-axis diameters of thermal lesions of each group were compared. All procedures were technically successful and a total of 38 lesions were produced. The mean short-axis and long-axis diameter of the coagulation necrosis in rabbits of group C (combination of RFA and PEI), were significantly larger than those of other groups: group A: 10.3 ± 2 mm and 11.4 ± 2 mm; group B: 3.1 ± 1 mm and 4.3 ± 2 mm; group C: 12.8 ± 3 mm and 17.8 ± 6 mm (p < 0.05). On contrast-enhanced CT scan, the lesions of rabbits of the group C appeared to be more frequently irregular compared to those of group A (20% in group A vs. 67% in group C). There were three complications including two localized hematomas and one cardiopulmonary failure. Combined RFA and PEI could increase the dimension of coagulation necrosis without increasing complications and therefore, may be successfully used for treating larger lesions.     

Gastrointestinal stromal tumors of the duodenum: CT and barium study findings

OBJECTIVE: The purpose of this study was to describe the CT and radiographic features of gastrointestinal stromal tumors of the duodenum. CONCLUSION: Gastrointestinal stromal tumors of the duodenum appear on barium studies as extrinsically compressing or submucosal masses with or without ulceration. These tumors usually appear on contrast-enhanced CT as well-defined masses with an exoenteric growth pattern and relatively good heterogeneous enhancement.     

Small (<or= 2 cm) hepatic lesions in colorectal cancer patients: detection and characterization on mangafodipir trisodium-enhanced MRI

OBJECTIVE: The purpose of this study was to evaluate whether mangafodipir trisodium (MnDPDP)-enhanced MRI improves the detection and characterization of small ( 2.0 cm). The differences between MnDPDP-enhanced MRI and helical CT with regard to the detection rates for hepatic lesions and metastases and with regard to the false-positive rates for hepatic metastases were analyzed using the McNemar test. The performances of MnDPDP-enhanced MRI and helical CT in indicating metastases of focal liver lesions were analyzed using receiver operating characteristic curves. RESULTS: No statistically significant differences were seen between MnDPDP-enhanced MRI and helical CT in the detection of all hepatic lesions (p = 0.383) and small lesions (p = 0.210). However, concerning the differentiation between benign and metastatic lesions, MnDPDP-enhanced MRI was superior to helical CT both for all hepatic lesions (p = 0.023) and for small lesions (p = 0.015), and remained better when the analyses were restricted to patients with histopathologic confirmation (p = 0.023 for both). MnDPDP-enhanced MRI changed the diagnosis of hepatic metastasis in nine (13.0%) of 69 patients. Of 12 metastases that were found on MnDPDP-enhanced MRI and missed on helical CT, 11 lesions (91.7%) were small. MnDPDP-enhanced MRI showed a significantly greater detection rate than helical CT for small hepatic metastases (p = 0.022). MnDPDP-enhanced MRI was better when the analyses were restricted to patients with histopathologic confirmation (p = 0.043). CONCLUSION: Although MnDPDP-enhanced MRI is equal to helical CT in detection of both all hepatic lesions and small lesions in patients with colorectal carcinoma, it is superior to CT in characterization of the lesions.     

Early biliary complications of laparoscopic cholecystectomy: evaluation on T2-weighted MR cholangiography in conjunction with mangafodipir trisodium-enhanced 3D T1-weighted MR cholangiography

OBJECTIVE: Our aim was to assess preliminary experience with combined conventional T2-weighted and mangafodipir trisodium (MnDPDP)-enhanced T1-weighted MR cholangiography in evaluating early biliary complications of laparoscopic cholecystectomy. SUBJECTS AND METHODS: Conventional heavily T2-weighted MR cholangiography with MnDPDP-enhanced T1-weighted MR cholangiography and ERCP were performed in seven patients with high clinical suspicion of biliary complications after laparoscopic cholecystectomy. The final diagnoses of complications were classified according to the presence and degree of bile duct injury, bile leakage, and retained stones. RESULTS: The diagnoses on MR cholangiography were as follows: complete transection and occlusion of the common bile duct with bile leakage (n = 3), partial strictures of the common bile duct with bile leakage (n = 1), cystic duct leakage (n = 1), partial ligation of an aberrant right hepatic duct (n = 1), and hemorrhage without biliary complication (n = 1). The final diagnoses at surgery (n = 2) and ERCP (n = 5) were as follows: complete transection and occlusion of the common bile duct with bile leakage (n = 2), partial strictures of the common bile duct with bile leakage (n = 2), cystic duct leakage (n = 1), partial ligation of an aberrant right hepatic duct (n = 1), and hemorrhage without biliary complication (n = 1). MR cholangiography accurately yielded the same findings as the final diagnoses, except in one case with partial stricture of the bile duct with bile leakage (overdiagnosed as complete occlusion on MR cholangiography). CONCLUSION: Combined conventional T2-weighted and MnDPDP-enhanced T1-weighted MR cholangiography may eliminate the use of other studies for the imaging of biliary complications after cholecystectomy if this preliminary data can be verified in a larger study.     

Pigmented villonodular synovitis of the temporomandibular joint: MR findings in four cases

OBJECTIVE: Although it is a rare condition, pigmented villonodular synovitis (PVNS) may involve temporomandibular joint (TMJ). The purpose of this study was to describe magnetic resonance (MR) findings of PVNS of the TMJ. METHODS AND MATERIAL: Between April 1992 and August 2000, four patients (two men and two women, 22-58-year-old) who had histologically proven diagnoses of PVNS in their TMJ were found in our institution. Their MR findings were reviewed retrospectively, and were correlated with pathologic findings. RESULTS: In all four patients, MR images invariably showed profound hypointensity on both T1- and T2-weighted sequences. This finding was seen diffusely and homogeneously throughout the lesion, and was considered to be due to paramagnetic effect attributed to heavy hemosiderin pigmentation, which was revealed by histopathological examination. MR images also showed aggressive nature of the lesions with adjacent skull base destruction and intracranial extension in two of them. CONCLUSION: As is the case in the other anatomic site, PVNS of the TMJ can be confidently diagnosed on MR imaging on the basis of the presence of hemosiderin. MR imaging also plays a pivotal role in surgical planning by precise and detailed localization of the lesion.     

Percutaneous sclerotherapy of lymphangiomas with acetic acid

PURPOSE: To evaluate the efficacy of percutaneous image-guided sclerotherapy of lymphangiomas with use of acetic acid. MATERIALS AND METHODS: Twelve patients with lymphangiomas were treated with acetic acid as the sclerosant. There were eight male patients and four female patients, ranging in age from 1 to 29 years (mean, 11 years). The lymphangiomas were located at the neck (n = 5), upper extremity (n = 3), axilla (n = 1), cervicomediastinum (n = 1), anterior chest wall (n = 1), and retroperitoneum (n = 1). Two patients had recurrent lymphangiomas after surgery and two patients had undergone failed sclerotherapy with another sclerosant. The acetic acid used as the sclerosant was 40%-50% in concentration, and the amounts used ranged from 2 mL to 70 mL (mean, 11.3 mL), which was equivalent to 4.6%-50% (mean, 30.6%) of the aspirated lymphatics. All procedures were performed under ultrasonographic and fluoroscopic guidance. The sclerosant was removed after sclerotherapy. All patients except one underwent one treatment session. RESULTS: Complete resolution of the lymphangioma was achieved in eight patients (66.7%), good resolution (>50% reduction) was achieved in three (25.0%), and poor resolution (<50% reduction) was seen in one (8.3%). Complications encountered included pneumonitis adjacent to the lymphangioma (n = 1), pain (n = 2), hematuria (n = 1), and tingling sensation in the forearm (n = 1). CONCLUSION: Percutaneous sclerotherapy of the lymphangiomas with use of acetic acid is an effective method without serious complications.