Quantitative 2- and 3-dimensional analysis of pharmacokinetic model-derived variables for breast lesions in dynamic, contrast-enhanced MR mammography.

PURPOSE: 2- and 3-dimensional evaluation of quantitative pharmacokinetic parameters derived from the Tofts model modeling dynamic contrast enhancement of lesions in MR mammography. MATERIALS AND METHODS: In 95 patients, MR mammography revealed 127 suspicious lesions. The initial rate of enhancement was coded by color intensity, the post-initial enhancement change is coded by color hue. 2D and 3D analysis of distribution of color hue and intensity, vascular permeability and extracellular volume were performed. RESULTS: In 2D, malignant lesions showed significant higher number of bright red, medium red, dark red, bright green, medium green, dark green and bright blue pixels than benign lesions. In 3D, statistical significant differences between malignant and benign lesions was found for all this parameters. Vascular permeability was significant higher in malignant lesions than in benign lesions. Regression model using the 3D data found that the best discriminator between malignant and benign lesions was combined number of voxels and medium green pixels, with a sensitivity of 79.4% and a specificity of 83.1%. CONCLUSIONS: Quantitative analysis of pharmacokinetic variables of contrast kinetics showed significant differences between malignant and benign lesions. 3D analysis showed superior diagnostic differentiation between malignant and benign lesions than 2D analysis. The parametric analysis using a pharmacokinetic model allows objective analysis of contrast enhancement in breast lesions.

A physiologic in vitro model of the inferior vena cava with a computer-controlled flow system for testing of inferior vena cava filters.

RATIONALE AND OBJECTIVES: The authors develop a physiologic in vitro model of the inferior vena cava (IVC) for testing of filters. METHODS: The model is driven by a centrifugal pump. A computer-controlled electromagnetic valve is used for generation of different flow patterns. Limitation of the pressure increase in case of IVC occlusion is achieved by a bypass circuit. A glycerin solution is used for perfusion. Artificial clots are made from polyacrylamide gel. Data acquisition includes continuous monitoring of flow and difference pressure over the filter and video recording of the testing events. RESULTS: The model can generate constant and pulsatile flows. The pressure increase can be limited to 70 mm Hg in case of occlusion. Calculation of the flow velocities in the IVC is possible. A classification of thrombus capturing is presented. The testing of most of the results are reproducible. CONCLUSIONS: The in vitro model simulates the physiologic conditions in the IVC. It can be used for comparative testing of different filters and the evaluation of new filter designs.

Diffusion-weighted MR imaging after angioplasty or angioplasty plus stenting of arteries supplying the brain.

BACKGROUND AND PURPOSE: There has been concern regarding the safety of revascularization procedures of vessels supplying the brain vessels because of the risk of cerebral embolization during the procedure. We have observed a high incidence of hyperintense lesions on diffusion-weighted MR images of the brain after stenting at the carotid bifurcation. The hypothesis of this study is that diffusion-weighted MR imaging of the brain can reveal new diffusion abnormalities after angioplasty or angioplasty plus stenting of arteries supplying the brain, other than at the carotid bifurcation. Therefore, we prospectively obtained diffusion-weighted MR images of the brain before and after such revascularization procedures. METHODS: Thirty-seven revascularization procedures were performed in 32 patients. Eleven interventions were performed at the distal internal carotid artery, two at the external carotid artery, two at the common carotid artery, five at the innominate artery, five at the vertebral artery, and 12 at the proximal subclavian artery. Diffusion-weighted MR imaging of the brain was performed before and 24 hours after the procedures. RESULTS: After eight (22%) of 37 procedures, new hyperintensities were visible on the diffusion-weighted MR images. With six of these eight procedures, the hyperintensities occurred in the vascular territory supplied by the treated vessel. In total, 35 new cerebral lesions could be seen, 33 (94%) of which occurred in the vascular territory supplied by the treated vessel. None of the patients in whom new diffusion abnormalities were found had new neurologic symptoms or deficits. No new lesions could be seen after procedures at the subclavian artery. CONCLUSION: Revascularization procedures of arteries supplying the brain were associated with new lesions on the diffusion-weighted MR images of the brain after 22% of the procedures, provided that MR imaging could be performed, indicating the occurrence of cerebral microemboli during such procedures. Diffusion-weighted MR imaging of the brain can be used as a tool to assess the impact of modifications of procedural technique and/or the use of cerebral protection devices on the occurrence of such lesions.

Gastric leiomyosarcoma in a child.

Gastric leiomyosarcoma is a rare tumor in pediatric patients. The histological differentiation between leiomyoma and leiomyosarcoma is difficult. Computed tomography may allow the presumptive diagnosis of leiomyosarcoma to be made preoperatively and the surgical treatment can be planned in advance. We report a case of gastric leiomyosarcoma in a 2-year old boy. Ultrasonography and computed tomography demonstrated an inhomogeneous mass with areas of tumor necrosis and calcifications in the left upper quadrant.

Diagnosis of abdominal masses with percutaneous biopsy guided by ultrasound.

OBJECTIVE: To assess the accuracy and safety of percutaneous biopsy of abdominal masses guided by ultrasound. DESIGN: Prospective study. SETTING: Combined gastroenterology service, Scarborough Hospital. PATIENTS: 108 Consecutive patients identified as having a discrete mass on diagnostic ultrasound examination of the abdomen. INTERVENTION: A sample of tissue was obtained with an aseptic technique under local anaesthesia: an 18 steel wire gauge needle (Tru-Cut) was mounted in a spring loaded firing device (Biopty gun) that was advanced under simultaneous ultrasound scanning, permitting precise localisation of the target organ. MAIN OUTCOME MEASURE: Results of histological examination of tissue specimens. RESULTS: Biopsy failed in four patients. Adequate histological specimens were obtained in 104 patients with masses in the liver (31), pancreas (37), kidney (10), and adrenal glands (six) and in 20 undiagnosed abdominal and retroperitoneal masses. Follow up was until death or confirmation of the diagnosis. Three complications but no deaths occurred. Malignancy was suspected in 84 patients before biopsy. This was confirmed in 70 patients, in 26 of whom confirmation of dissemination obviated the need for further investigation. In 10 patients biopsy indicated a previously unsuspected primary tumour, and in 12 it showed only a benign lesion. Among 24 patients considered to have benign disease biopsy showed an unsuspected neoplasm in seven. Use of biopsy thus had a major effect on clinical management in 55 patients. Four false negative but no false positive diagnoses resulted from the procedure. CONCLUSION: Percutaneous biopsy of abdominal and retroperitoneal masses under ultrasound guidance is a safe and accurate method of obtaining a histological diagnosis. The results obtained have a considerable effect on clinical management.

MR-guided vacuum-assisted breast biopsy with a handheld biopsy system: clinical experience and results in postinterventional MR mammography after 24 h.

This prospective study evaluates the feasibility of the magnetic resonance (MR)-guided vacuum-assisted breast biopsy with a handheld vacuum-biopsy system and documents the biopsy results with MR mammography 24 h after the procedure. MR-guided biopsy was undertaken in 33 patients with 34 lesions on dynamic MR mammography. The interventions were performed with the handheld 10-gauge Vacora vacuum-biopsy system. In all cases, dynamic MR mammography was performed 24 h after the procedure to determine the extent of the lesion removal and to identify the lesions that were missed. In 5/34 (14.7%) lesions, biopsy was not performed because no suspicious lesion was identified on the day of biopsy. In 25/29 (86.2%) lesions, the biopsy was successfully performed with a complete removal in 4/29 (13.8%) and a partial removal of 21/29 (72.4%) lesions. In 4/29 (13.8%) interventions the lesion was missed with the biopsy. In one case, histopathology after surgical excision revealed ductal carcinoma in situ. Histopathology revealed 9/29 (31%) malignant and 20/29 (68.9%) benign lesions. MR-guided vacuum-assisted breast biopsy with the handheld Vacora vacuum-biopsy system is technically feasible in most cases. MR mammography 24 h after the biopsy should be performed in those cases in which the biopsy success is unclear immediately after the procedure.

Magnetic resonance imaging of the ovaries of healthy women: determination of normal values.

PURPOSE: To establish normal values for the volume and maximal diameter of ovaries and ovarian follicles and for the number of ovarian follicles in magnetic resonance imaging (MRI) based on menstrual cycle phase and age. MATERIAL AND METHODS: We performed MRI of the pelvis on 100 healthy women. Volume of the ovaries and largest ovarian follicles and the number of ovarian follicles were determined by menstrual cycle phase and age. RESULTS: The mean volume of the ovaries significantly increased with age and reached its peak between 31 and 40 years, and subsequently decreased. The mean volume of the largest ovarian follicles also significantly increased with age to reach its peak at 41-50 years. The highest mean numbers of ovarian follicles were found at 20-40 years. When the volumes of ovaries and of the largest ovarian follicles, and the number of ovarian follicles were compared between the first and second phase of the menstrual cycle, no significant differences were found. CONCLUSION: The volume and maximal diameter of ovaries and ovarian follicles and the number of ovarian follicles differ significantly with age, but not between the two phases of the menstrual cycle. Knowledge of MRI-related normal values can be expected to aid the early identification of ovarian pathologies.

Patellar metastasis from a malignant melanoma.

We report a patient with a patellar metastasis from a malignant melanoma. Only 16 other cases have been previously described in detail in the literature. A lytic lesion in the patella is most often caused by a benign tumour, but a primary or secondary malignant tumour has to be excluded.

Cervical diastematomyelia and syringohydromyelia in a myelomeningocele patient.

A case of cervical diastematomyelia and syringohydromyelia in a 16-year-old female myelomeningocele patient is reported. Progressive weakness of the upper extremity led to an MR examination of the brain and spine, which revealed hydrocephalus, Chiari II malformation, cervical diastematomyelia with a syringohydromyelic cavity in each hemicord and a large dural sac in the lumbar region. Operative therapy consisted of detethering and shunting of the two syringes. Soon after surgery her symptoms improved. The need for early complete MR imaging of myelomeningocele patients presenting with new symptoms is emphasized.

Bilateral subclavian steal syndrome: treatment with percutaneous transluminal angioplasty and stent placement.

A 66-year-old man presented with bilateral subclavian steal syndrome (SSS) due to proximal subclavian artery occlusions. He was treated by percutaneous transluminal balloon angioplasty (PTA) and stent implantation in the left subclavian artery and by PTA alone in the right subclavian artery. We could demonstrate that interventional treatment of symptomatic bilateral SSS is possible. If PTA alone is insufficient, stent implantation should be considered.

Congenital absence of the internal carotid artery and the basilar artery with persistent trigeminal artery associated with coarctation of the aorta.

We report a case of congenital absence of the cervical and petrous part of the left internal carotid artery, the middle and proximal part of the basilar artery, and the V4 segment of the left vertebral artery associated with a left persistent trigeminal artery and a coarctation of the aorta. The left cerebral vessels are supplied via the anterior communicating artery and the left persistent trigeminal artery. The coexisting coarctation of the aorta led to a subclavian steal phenomenon. The alteration of the cerebral hemodynamics has to be taken in consideration when performing cerebral angiography and surgical correction in such a case.

The boneless neonate: a severe form of achondrogenesis type I.

We report a case of a severe form of achondrogenesis type I. Prenatal ultrasonography showed a micromelic fetus; bony structures could not be identified. Postnatal radiographs revealed some foci of ossification in the ossa ilia, the clavicles, the upper and the lower jaw and the base of the skull. The long bones, the vertebral column and the ribs were not visible. The diagnosis was established by histologic examination of the growth plates.

Lead dislodgment of a permanent pacemaker due to removal of a temporary pacing electrode.

A 63-year-old male received a transvenous temporary pacemaker for bradyarrhythmia following mitral valve replacement and tricuspid valve annuloplasty. A transvenous permanent pacemaker was implanted the following day due to persistence of the bradyarrythmia and pacemaker dependency of the patient. Later the same day during removal of the temporary pacing electrode the permanent pacing lead was dislodged and had to be operatively repositioned. To avoid this complication, the position of pacemaker leads should be checked postoperatively with a frontal and lateral chest radiograph, and fluoroscopy should be used during removal of a temporary lead.

Rectum and sigmoid colon necrosis due to cholesterol embolization after implantation of an aortic stent-graft.

Endovascular treatment of abdominal aortic aneurysms (AAAs) with stent-grafts is increasingly performed. Recent studies have shown that stent-graft placement for AAA is technically feasible and can effectively exclude aneurysms from the circulation. However, complications related to the procedure, such as graft thrombosis, migration of the prosthesis, peripheral embolization, and leaks with incomplete exclusion of the aneurysmal sac, have been reported. We report a case of rectum and sigmoid colon necrosis with fatal outcome due to cholesterol embolization after implantation of a stent-graft for an infrarenal AAA.

Sequential transarterial chemoembolization for unresectable advanced hepatocellular carcinoma.

PURPOSE: The aim of this prospective study was to evaluate the feasibility, safety, and efficacy of sequential transarterial chemoembolization (TACE) for patients with unresectable advanced hepatocellular carcinoma (HCC). METHODS: Twenty-one consecutive patients with unresectable T3 and T4 HCC were treated by sequential TACE (median time interval between treatments 7 weeks) up to six times with an emulsion of lipiodol, epirubicin, and cisplatin. All TACE procedures were performed as unilobar or whole-liver chemoembolization. RESULTS: An average of 3.9 TACE procedures were performed per patient. One primary and two secondary technical failures occurred. No procedural death was observed. After exclusion of the patient with the primary technical failure and 3 patients with extrahepatic disease, the survival rates for the remaining 17 patients at 6, 12, 18, and 24 months were 70.6%, 52.9%, 44.1%, and 33.1%, respectively. CONCLUSION: Sequential TACE is a safe procedure in patients with unresectable advanced HCC and feasible in most cases. It seems to prolong the survival time compared with historical series of untreated patients.

In vitro model for the evaluation of inferior vena cava filters: effect of experimental parameters on thrombus-capturing efficacy of the Vena Tech-LGM filter.

PURPOSE: To determine the experimental parameters in an in vitro model that influence the thrombus-capturing efficacy of the Vena Tech-LGM filter. MATERIALS AND METHODS: The Vena Tech-LGM filter was evaluated in an in vitro model of the vena cava with a computer-controlled flow system with a total of 5,200 thrombi. The influences of the following experimental parameters on the capture rate were analyzed with a multiple logistic regression model: type of testing (single, double, and multiple shot testing), thrombus diameter and length, IVC diameter and orientation, flow quality and quantity, flow velocity, and the length of the prepositioned thrombus. RESULTS: A significant influence on the capture rate could be demonstrated for the type of testing, the thrombus diameter and length, the IVC diameter, and with double shot testing for the length of the prepositioned thrombus and the IVC orientation. The flow quality and the peak velocity were not significant. Based on these results, a protocol for in vitro testing of IVC filters was designed. CONCLUSIONS: Experimental parameters influence the thrombus-capturing efficacy of the Vena Tech-LGM filter and should be taken into account when in vitro testing is performed.

Digital chest radiography with a large-area flat-panel silicon X-ray detector: clinical comparison with conventional radiography.

This was a radiologists' preference study to compare a digital chest radiography system that utilizes a large-area silicon flat-panel detector with conventional radiography for visualizing anatomic regions of the chest. Conventional and digital posteroanterior (PA) and lateral chest radiographs were obtained in 115 patients. The PA and lateral image pairs were compared independently by three radiologists rating the overall appearance, 11 anatomic regions in the PA, and 9 in the lateral views. Statistical analysis was performed with the Wilcoxon signed-rank test with Bonferroni-Holm adjustment (p=0.05). For the PA view, the digital system performed significantly better for the overall appearance and for all anatomic regions except for the peripheral pulmonary vasculature and hilum, where no significant difference was found. For the lateral digital images, the regions trachea, costodiaphragmatic recess, and hilum were rated significantly worse. The regions retrosternal and retrocardiac lung were rated significantly better. The other regions and the overall appearance showed no significant differences. The described digital chest radiography system showed statistically superior visualization of anatomic regions for PA and an ambiguous performance for lateral images as compared with conventional radiography. After changing some image processing parameters for the lateral view, this system may be suitable for digitalization of chest radiography.