Detection of recurrent hernia and intraabdominal adhesions following incisional hernia repair: a functional cine MRI-study

BACKGROUND

To non-invasively identify incisional hernia repair implanted synthetic meshes with MRI, and also focusing on the evaluation of postsurgical complications such as adhesions.

METHODS

A total of 43 patients underwent either laparoscopic intraperitoneal onlay-mesh or open abdominal wall repair using preperitoneal layers. The patients were examined using a true-fast-imaging-with-steady-state-precession (trueFISP)-sequence in transverse/sagittal orientation with a section-by-section dynamic depiction of induced visceral slide. A 9-segment-abdominal-map was used to document the adhesion location/type. The MR-images were analysed regarding hernia relapse, layer-morphology, rectus-abdominis muscle-condition, and abdominal wall mobility. In 12 patients pre- and postsurgery-MRI was performed.

RESULTS

Time range between surgery and examination was 6-36 months. In all laparoscopy-patients the meshes were identified. For open surgery the mesh was not visualized in 20, but was seen in 6 cases. A total of 11 cases showed a recurrent hernia. Seventy intraabdominal adhesions were detected. Fifteen patients had restricted mobility. 20 patients showed an rectus-abdominis-muscle-asymmetry. Comparing pre- and post-op-MRI, 6 out of 8 patients with open repair showed thick scar-plaques. Three patients with open repair had new adhesion-formations postoperatively.

CONCLUSION

Functional cine MRI is suitable for follow-up studies in patients after hernia repair to detect and evaluate the implanted meshes. Typical complications like intestinal adhesions and abdominal wall dysmotility can be assessed as well.

Advancing radiology through informed leadership: summary of the proceedings of the Seventh Biannual Symposium of the International Society for Strategic Studies in Radiology (IS(3)R), 23-25 August 2007

The International Society for Strategic Studies in Radiology (IS³R) brings together thought leaders from academia and industry from around the world to share ideas, points of view and new knowledge. This article summarizes the main concepts presented at the 2007 IS³R symposium, providing a window onto trends shaping the future of radiology. Topics addressed include new opportunities and challenges in the field of interventional radiology; emerging techniques for evaluating and improving quality and safety in radiology; and factors impeding progress in molecular imaging and nanotechnology and possible ways to overcome them. Regulatory hurdles to technical innovation and drug development are also discussed more broadly, along with proposals for addressing regulators’ concerns and streamlining the regulatory process.

Radiofrequency ablation after selective internal radiation therapy with Yttrium90 microspheres in metastatic liver disease-Is it feasible?

This retrospective study analyzes, whether patients suffering from extensive hepatic metastatic disease treated with SIRT can become suitable candidates for RFA.Within 38 months 46 patients (26 female, 20 male; age 32-75 years) bearing an extensive hepatic metastatic disease were treated with SIRT. Patients suffered from metastases of breast cancer (16/46), colorectal cancer (CRC) (21/46), neuroendocrine (3/46), and other primary carcinomas (6/46). The indication for SIRT was otherwise untreatable metastases confined to the liver. Forty-three patients received single-session whole-liver radioembolization treatment using Yttrium90 resin microspheres with a mean activity of 2.13GBq. In 1 patient SIRT was confined to the left and in 2 patients to the right liver lobe. In 3 patients major complications (2/3 gastric ulceration and 1/3 oedematous pancreatitis) and in 24 patients minor complications occurred (acute abdominal/epigastric pain and/or nausea). Follow-up CT and/or MRI were obtained in 44 of 46 patients. In 5 of 44 patients tumor load decreased substantially (3/5 breast cancer, 1/5 CRC and 1/5 pancreatic cancer) making RFA feasible. The patients were referred for RFA after the first 3-month follow-up. RFA of the liver was successful in all cases in terms of complete ablation. In selected patients radioembolization is able to downstage liver metastases to an extent making a subsequent RFA suitable and therefore allows increasing the number of patients with a "complete response" after a minimally invasive therapy.

Inadvertent Intra-Arterial Contrast Agent Injection Mimicking Bilateral Occlusion of the Internal Carotid Arteries in a Patient With Suspected Stroke on Maximum-Slope, Nondeconvolution Perfusion Computed Tomography

Background and Purpose— Inadvertent contrast agent injection in the left cubital artery may lead to decisively altered perfusion parameters in stroke CT. These effects have not previously been described.

Summary of Case— A 77-year-old woman with a suspected stroke underwent subsequent stroke CT imaging. No signs of intracranial hemorrhage or acute cerebral ischemia were noted on nonenhanced CT. Qualitative analysis of perfusion CT using the maximum slope model demonstrated an extremely delayed and decreased perfusion of the territories of the anterior circulation system and higher values of cerebral blood flow and blood volume of the posterior circulation system mimicking a bilateral occlusion of the internal carotid arteries. CT angiography revealed no relevant stenoses or occlusions of the internal carotid arteries. Intensive investigation into the potential causes of these controversial findings showed that the contrast medium was administered into the left brachial artery due to inadvertent arterial placement of the antecubital catheter.

Conclusions— It is important to be familiar with this unusual constellation of perfusion parameters to avoid diagnostic uncertainty in patients with an inadvertent intra-arterial application of contrast agent.

Magnetic resonance noise measurements and signal-quantization effects at very low noise levels

The well-known noise distributions of magnetic resonance imaging (MRI) data (Rayleigh, Rician, or non-central chi-distribution) describe the probability density of real-valued (i.e., floating-point) signal intensities. MR image data, however, is typically quantized to integers before visualization or archiving. Depending on the scaling factors applied before the quantization and the signal-to-noise ratio (SNR), very low noise levels with substantial artifacts due to the quantization process can occur. The purpose of this study was to analyze the consequences of the signal quantization, to determine the theoretical absolute lower limit for noise measurements in discrete data, and to evaluate an improved method for noise and SNR measurements in the presence of very low noise levels. Image data were simulated with original noise levels of between 0.02 and 2.00. Noise measurements were performed based on the properties of background and foreground data using the conventional approach, which exploits the standard deviation or mean value of the signal, and a maximum-likelihood approach based on the relative frequencies of the observed discrete signal intensities. Substantial deviations were found for the conventionally determined noise levels, while noise levels comparable to or lower than the quantization error can be accurately estimated with the proposed maximum-likelihood approach.

Whole-body MRI at 1.5 T and 3 T compared with FDG-PET-CT for the detection of tumour recurrence in patients with colorectal cancer

The purpose of this study was to assess the diagnostic accuracy of whole-body MRI (WB-MRI) at 1.5 T or 3 T compared with FDG-PET-CT in the follow-up of patients suffering from colorectal cancer. In a retrospective study, 24 patients with a history of colorectal cancer and suspected tumour recurrence underwent FDG-PET-CT and WB-MRI with the use of parallel imaging (PAT) for follow-up. High resolution coronal T1w-TSE and STIR sequences at four body levels, HASTE imaging of the lungs, contrast-enhanced T1w- and T2w-TSE sequences of the liver, brain, abdomen and pelvis were performed, using WB-MRI at either 1.5 T (n = 14) or 3 T (n = 10). Presence of local recurrent tumour, lymph node involvement and distant metastatic disease was confirmed using radiological follow-up within at least 5 months as a standard of reference. Seventy seven malignant foci in 17 of 24 patients (71%) were detected with both WB-MRI and PET-CT. Both investigations concordantly revealed two local recurrent tumours. PET-CT detected significantly more lymph node metastases (sensitivity 93%, n = 27/29) than WB-MRI (sensitivity 63%, n = 18/29). PET-CT and WB-MRI achieved a similar sensitivity for the detection of organ metastases with 80% and 78%, respectively (37/46 and 36/46). WB-MRI detected brain metastases in one patient. One false-positive local tumour recurrence was indicated by PET-CT. Overall diagnostic accuracy for PET-CT was 91% (sensitivity 86%, specificity 96%) and 83% for WB-MRI (sensitivity 72%, specificity 93%), respectively. Examination time for WB-MRI at 1.5 T and 3 T was 52 min and 43 min, respectively; examination time for PET-CT was 103 min. Initial results suggest that differences in accuracy for local and distant metastases detection using FDG-PET-CT and WB-MRI for integrated screening of tumour recurrence in colorectal cancer depend on the location of the malignant focus. Our results show that nodal disease is better detected using PET-CT, whereas organ disease is depicted equally well by both investigations.

Comparison of CT colonography, colonoscopy, sigmoidoscopy and faecal occult blood tests for the detection of advanced adenoma in an average risk population

BACKGROUND AND AIMS

This prospective trial was designed to compare the performance characteristics of five different screening tests in parallel for the detection of advanced colonic neoplasia: CT colonography (CTC), colonoscopy (OC), flexible sigmoidoscopy (FS), faecal immunochemical stool testing (FIT) and faecal occult blood testing (FOBT).

METHODS

Average risk adults provided stool specimens for FOBT and FIT, and underwent same-day low-dose 64-multidetector row CTC and OC using segmentally unblinded OC as the standard of reference. Sensitivities and specificities were calculated for each single test, and for combinations of FS and stool tests. CTC radiation exposure was measured, and patient comfort levels and preferences were assessed by questionnaire.

RESULTS

221 adenomas were detected in 307 subjects who completed CTC (mean radiation dose, 4.5 mSv) and OC; 269 patients provided stool samples for both FOBT and FIT. Sensitivities of OC, CTC, FS, FIT and FOBT for advanced colonic neoplasia were 100% (95% CI 88.4% to 100%), 96.7% (82.8% to 99.9%), 83.3% (95% CI 65.3% to 94.4%), 32% (95% CI 14.9% to 53.5) and 20% (95% CI 6.8% to 40.7%), respectively. Combination of FS with FOBT or FIT led to no relevant increase in sensitivity. 12 of 45 advanced adenomas were smaller than 10 mm. 46% of patients preferred CTC and 37% preferred OC (p<0.001).

CONCLUSIONS

High-resolution and low-dose CTC is feasible for colorectal cancer screening and reaches sensitivities comparable with OC for polyps >5 mm. For patients who refuse full bowel preparation and OC or CTC, FS should be preferred over stool tests. However, in cases where stool tests are performed, FIT should be recommended rather than FOBT.

CT fluoroscopy-guided percutaneous vertebroplasty for the treatment of osteolytic breast cancer metastases: results in 62 sessions with 86 vertebrae treated

PURPOSE

This retrospective study aimed to assess the results of computed tomographic (CT) fluoroscopy-guided percutaneous vertebroplasty (PV) of painful osteolytic spinal metastases from breast cancer, focusing on the frequency and clinical impact of polymethylmethacrylate (PMMA) leaks.

MATERIALS AND METHODS

Within 48 months, 53 patients (52 women; mean age of 62 y +/- 13) with painful osteolytic breast cancer metastases underwent vertebroplasty. Eighty-six vertebrae were treated in 62 sessions under CT fluoroscopy guidance (single slice and four- and 16-row CT). In the planning CT scan, osteolytic destruction (ie, none, < or =25%, < or =50%, < or =75%, or < or =100%) was assessed regarding the vertebral cross-sectional area, the cortical border of the spinal canal, and the outer circumference. CT performed after vertebroplasty was used to detect local PMMA leaks (intradiscal, intraspinal, paravertebral, intercostovertebral/posterolateral, and vascular). Patient charts were reviewed with respect to adverse events. Clinical outcome was assessed on a visual analog scale (VAS) 24 hours before, immediately after, and 6 months after PV.

RESULTS

Overall, 37.2%, 12.8%, and 1.2% of vertebrae (N = 86) showed at least a 50% osteolytic involvement of the cross-sectional area, spinal canal, and outer vertebral cortex, respectively. Intradiscal, intraspinal, paravertebral, and intercostovertebral/posterolateral leaks were seen in 31.3%, 26.9%, 26.9%, and 14.9% of vertebrae, respectively. The ratio of basivertebral to segmental venous leaks was 22.4%/23.9%. No major complications (eg, radiculopathy or pulmonary embolism) occurred. VAS scores decreased significantly (P < .05) from 6.4 at 24 hours before PV to 3.4 at a mean follow-up of 9.2 months.

CONCLUSIONS

PV of osteolytic breast cancer metastases can be performed safely under CT fluoroscopic guidance even with substantial involvement of the vertebral cross-sectional area or cortical bone. A high clinical success rate was achieved and cortical and vascular PMMA leaks had no impact.

[Therapy response of liver tumors after selective internal radiation therapy]

Selective internal radiation therapy (SIRT) is used for the treatment of patients with liver tumors, especially for those with hepatocellular carcinoma (HCC) or liver metastases from various primary tumors. Currently this innovative treatment concept is recommended when established state-of-the-art treatment regimes have failed and tumor progression is noted or if the treatment has to be abandoned because of intolerable toxic effects. For SIRT small biocompatible microspheres (SIR-Spheres(R)) are labelled with the radioactive isotope 90Yttrium, a pure beta emitter, and are superselectively infused into the hepatic arteries. The microspheres are collected in the precapillary vessels in and surrounding the tumor. The beta radiation of 90Yttrium has an average penetration in tissue of approximately 2.5 mm and results in very high doses of radiation being selectively targeted to metastases providing protection to the surrounding healthy liver tissue. In this paper we review the results of SIRT in patients with hepatic metastases from colorectal cancer, breast cancer, neuroendocrine tumors and primary liver cancer (HCC).

[Solid pseudopapillary pancreas tumors--often neglected]

Solid pseudopapillary tumors of the pancreas (SPTP) are rare tumors of the pancreas with low malignancy potential and a very good prognostic outcome after surgery. They typically occur in young women or adolescents and consist of solid, cystic and cystic-hemorrhagic components.Imaging findings in these tumors are characteristic and include a fibrotic capsule with a clear delineation and exhibit solid and cystic-hemorrhagic signal and density characteristics. Calcifications may be present in the periphery of the tumor. The tumor capsule shows contrast enhancement, the solid components in the periphery enhance in the early phase and gradually and inhomogeneously in late phases. MRI is superior to CT and other imaging modalities for characterization of SPTP. Awareness and knowledge of this tumor entity with an excellent prognosis is crucial to guide the patient towards effective, predominantly organ-sparing surgical treatment.

[Tumor-like lesion of the pancreas in chronic pancreatitis : imaging characteristics of computed tomography]

OBJECTIVE

The aim of this study was to describe the imaging findings for inflammatory pseudotumors in patients with chronic pancreatitis as detected in computed tomography (CT).

MATERIALS AND METHODS

In this retrospective study 20 patients with chronic pancreatitis were included, who underwent an abdominal CT scan. In all patients the diagnosis was confirmed by surgery and histopathology. Imaging findings which have previously been described as typical for chronic pancreatitis and for inflammatory pseudotumors were assessed by two radiologists in consensus. Values of tissue density (HU) at CT were measured within the lesions and in the surrounding pancreatic tissue.

RESULTS

In 90% of patients with histologically proven chronic pancreatitis, CT showed corresponding indicative findings. In 10 patients the resected specimen revealed an inflammatory pseudotumor, which was located in all cases within the pancreatic head. Using CT these 10 patients presented with calcifications within the lesion in 50% of the cases, an irregular dilatation of the main pancreatic duct in 90%, a "double duct sign" in 70%, an interrupted main pancreatic duct in the area of the lesion in 50%, a "duct penetrating sign" in 30%, an infiltration of adjacent structures in 10% and pathologically enlarged lymph nodes in 100% of the cases. In the venous contrasting phase six tumors were hypodense and four isodense compared to the surrounding pancreatic tissue. In six patients biphasic CT was performed and the mean difference in attenuation between inflammatory pseudotumors and surrounding parenchyma was significantly higher in the pancreatic phase than in the venous phase.

DISCUSSION

Differentiation between inflammatory pseudotumors and adenocarcinoma remains difficult or even impossible. Typical signs indicative of an adenocarcinoma of the pancreatic head, such as dilatation of the common bile duct and/or the main pancreatic duct as well as enlarged lymph nodes, were also found in patients with inflammatory pseudotumors. Inflammatory pseudotumors showed low contrast between lesions and parenchyma in the venous phase and calcifications within the solid part of the tumor.

Impact of RIS/PACS integrated speech recognition on report availability

First adopted by radiology more than 25 years ago, speech recognition (SR) technology has been significantly improved. State-of-the-art SR systems are characterized by extensive vocabularies and advanced mathematical language models which theoretically allow for mean recognition rates far beyond 90%. Commercial arguments for SR implementation are a reduction of report turnaround times (RTT) and cost savings by the elimination of transcriptionist services. In contrast, the (potential) negative impact of front-end SR on radiologists' productivity has been discussed extensively in the literature. This study was conducted in a 1400 bed university hospital and aims to retrospectively evaluate the effect of an SR system on report availability and RTT over a 1.5 year period after integration into a preexisting RIS/PACS installation. Front-end SR with editing of the draft report by the radiologist (night and weekend reports) and back-end SR with correction of the draft report (put out by the recognition servers) by transcriptionists (reports generated during routine working time) were utilized.

Magnetic resonance imaging in early stage charcot arthropathy: correlation of imaging findings and clinical symptoms

OBJECTIVE

To report on qualitative and quantitative MRI findings in early stage of diabetic osteoarthropathy (CA) and correlation with clinical symptoms.

MATERIALS AND METHODS

Clinical data of 13 patients (mean age = 61.2 years) with Charcot arthropathy (CA, Eichenholtz 0) were compared with findings in native and contrast-enhanced MRI. 12 patients had diabetes mellitus (7 type 2, 5 type 1), one had idiopathic polyneuropathy. Evaluation was performed at acute stage of CA and at a 4 months follow-up. After baseline assessment, patients were treated with pressure-relieving means. Mean values of signal-intensity in short T1 inversion recovery (STIR) images of bones of the foot and ankle and corresponding contrast-enhancement were evaluated. Additional MRI-findings (soft tissue edema, varicosis, tenovaginitis, joint effusion) were analyzed. A correlation with symptoms (reddening, swelling, hyperthermia, pain) was performed.

RESULTS

Bone marrow edema in affected bones significantly decreased (p<0.001). Soft tissue edema and pain showed a significant correlation with intensity of bone marrow edema (p<0.05). The presence of bone marrow edema in the STIR sequence was strongly associated with a corresponding contrast enhancement (p<0.0001, kappa-coefficients 0.976 at baseline and 0.953 at follow-up).

CONCLUSION

MRI in early stage of CA provides valuable diagnostic information on the activity of the disease. A significant correlation of intensity of bone marrow edema in MRI and some clinical parameters (soft tissue edema and pain) was found. Paramagnetic contrast-agent did not provide additional information. This is the first report on quantitative assessment of signal alterations in stage 0 CA before and after treatment.