Adverse events due to unnecessary radiation exposure in medical imaging reported in Finland.

INTRODUCTION: Adverse events in radiology are quite rare, but they do occur. Radiation safety regulations and the law obligate organizations to report certain adverse events, harm and near misses, especially events related to patients' health and safety. The aim of this study was to describe and analyse incidents related to radiation safety issues reported in Finland. METHODS: The data were collected from incident reports documented by radiology personnel concerning notifications of abnormal events in medical imaging made to the Radiation and Nuclear Safety Authority between 2010 and 2017. During these eight years, 312 reports were submitted. Only events reported from radiology departments were included; nuclear medicine, radiotherapy and animal radiology cases were excluded. The final number of reports was 293 (94%). RESULTS: The majority of the 293 approved reports were related to computed tomography (CT, 68.3%) and to X-ray examinations (27.6%). Altogether 82.9% of those irradiated were adults, most of whom were exposed to unnecessary radiation through CT (86.5%), 5.5% were children, and 4.4% pregnant women. The most common effective dose of unnecessary radiation was 1 mSv or less (89.7% of all examinations). The highest effective doses were reported in CT (from under 1 mSv-20 mSv and above). The reasons for the adverse events were incorrect identification (32%), incorrect procedure, site or side (30%); and human errors or errors of knowledge (20%). CONCLUSION: Adverse events occurred especially in CT examinations. It is important to collect and analyse incident data, assess the harmful events, learn from them and aim to reduce adverse events. IMPLICATIONS FOR PRACTICE: This study emphasizes the need for radiological personnel to obtain evidence-based information on adverse events and focus on training to improve patient safety.

Spectral entropy indicates electrophysiological and hemodynamic changes in drug-resistant epilepsy - A multimodal MREG study.

OBJECTIVE: Epilepsy causes measurable irregularity over a range of brain signal frequencies, as well as autonomic nervous system functions that modulate heart and respiratory rate variability. Imaging dynamic neuronal signals utilizing simultaneously acquired ultra-fast 10 Hz magnetic resonance encephalography (MREG), direct current electroencephalography (DC-EEG), and near-infrared spectroscopy (NIRS) can provide a more comprehensive picture of human brain function. Spectral entropy (SE) is a nonlinear method to summarize signal power irregularity over measured frequencies. SE was used as a joint measure to study whether spectral signal irregularity over a range of brain signal frequencies based on synchronous multimodal brain signals could provide new insights in the neural underpinnings of epileptiform activity. METHODS: Ten patients with focal drug-resistant epilepsy (DRE) and ten healthy controls (HC) were scanned with 10 Hz MREG sequence in combination with EEG, NIRS (measuring oxygenated, deoxygenated, and total hemoglobin: HbO, Hb, and HbT, respectively), and cardiorespiratory signals. After pre-processing, voxelwise SEMREG was estimated from MREG data. Different neurophysiological and physiological subfrequency band signals were further estimated from MREG, DC-EEG, and NIRS: fullband (0-5 Hz, FB), near FB (0.08-5 Hz, NFB), brain pulsations in very-low (0.009-0.08 Hz, VLFP), respiratory (0.12-0.4 Hz, RFP), and cardiac (0.7-1.6 Hz, CFP) frequency bands. Global dynamic fluctuations in MREG and NIRS were analyzed in windows of 2 min with 50% overlap. RESULTS: Right thalamus, cingulate gyrus, inferior frontal gyrus, and frontal pole showed significantly higher SEMREG in DRE patients compared to HC. In DRE patients, SE of cortical Hb was significantly reduced in FB (p = .045), NFB (p = .017), and CFP (p = .038), while both HbO and HbT were significantly reduced in RFP (p = .038, p = .045, respectively). Dynamic SE of HbT was reduced in DRE patients in RFP during minutes 2 to 6. Fitting to the frontal MREG and NIRS results, DRE patients showed a significant increase in SEEEG in FB in fronto-central and parieto-occipital regions, in VLFP in parieto-central region, accompanied with a significant decrease in RFP in frontal pole and parietal and occipital (O2, Oz) regions. CONCLUSION: This is the first study to show altered spectral entropy from synchronous MREG, EEG, and NIRS in DRE patients. Higher SEMREG in DRE patients in anterior cingulate gyrus together with SEEEG and SENIRS results in 0.12-0.4 Hz can be linked to altered parasympathetic function and respiratory pulsations in the brain. Higher SEMREG in thalamus in DRE patients is connected to disturbances in anatomical and functional connections in epilepsy. Findings suggest that spectral irregularity of both electrophysiological and hemodynamic signals are altered in specific way depending on the physiological frequency range.

Patient information regarding medical radiation exposure is inadequate: Patients' experience in a university hospital.

INTRODUCTION: It is suspected that little or no information is provided to patients regarding radiological examinations. The purpose was to evaluate the coverage, content and source of this information in a university hospital. METHODS: Altogether 147 patients (18-85 years) were interviewed after different examinations using a questionnaire. The patients had undergone 35 low (<1 mSv), 66 medium (1-10), and 46 high (>10) dose examinations. They were asked if they were informed about radiation use, the course or indication of the examination, the consequences of not having the examination, other options, the dose and risks of radiation, the source for the information and if any consent was enquired. RESULTS: 52 (35%) patients did not receive any information while 95 (65%) obtained some information. Fifty-six (38%) patients received an information letter, and 75 (51%) obtained oral information, mainly from the referrer or the radiographer. The information was mostly about indication, course or radiation use, very seldom about radiation risks and the other areas. Those with a nuclear medicine examination received information more often than those with other medium- or high-dose examinations (p = 0.004). The patients scored the received information as 2.2 (mean, SD 1.3) on a Likert scale from 1 (poor) to 5 (good). CONCLUSION: Patients obtained inadequate information regarding radiological examinations in a university hospital. The information was provided non-systematically from various sources. The results help to set up practical guidelines for systematic information and to follow up their efficiency. The mode of operation might be helpful elsewhere in the future.

Association between adolescent sport activities and lumbar disk degeneration among young adults.

The relationship between different sport activities and lumbar intervertebral disk degeneration (DD) is largely unknown. We evaluated whether adolescent participation in different sports is associated with lumbar DD in a population-based birth cohort of young adults. A total of 558 young adults (325 females and 233 males) underwent magnetic resonance imaging (MRI, 1.5-T scanner). A DD sum score, based on the Pfirrmann grading, was calculated for all lumbar levels. The sum score was categorized into no DD, 1, 2, or at least 3. Participation in different sport activities was self-reported by postal surveys at 16, 18, and 19 years, and three groups were formed based on participation frequency in 11 sports: (a) highly active (at least twice a week), (b) moderately active (2-4 times a month), and (c) inactive (maximum once a month). Cumulative odds ratios (COR) and their 95% confidence intervals (CI) were obtained for each sport by ordinal logistic regression, adjusting for gender, body mass index, age, socioeconomic status, smoking, and other sports. Highly active participation in jogging/running and swimming was associated with a higher DD sum score (COR: 3.0; 95% CI: 1.4-6.3 and 5.0; 1.7-15.2, respectively) compared to inactive participation, whereas highly active participation in skating showed low COR. In conclusion, running and swimming at least twice a week in early adulthood are potentially associated with lumbar DD. Follow-up studies with MRI are needed to show whether frequent exposure to running or swimming has further effect on the integrity of lumbar intervertebral disks.

Comparison between DICOM-calibrated and uncalibrated consumer grade and 6-MP displays under different lighting conditions in panoramic radiography.

OBJECTIVES: To compare observer performance in the detection of anatomical structures and pathology in panoramic radiographs using consumer grade with and without digital imaging and communication in medicine (DICOM)-calibration and 6-megapixel (6-MP) displays under different lighting conditions. METHODS: 30 panoramic radiographs were randomly evaluated on three displays under bright (510 lx) and dim (16 lx) ambient lighting by two observers with different years of experience. Dentinoenamel junction, dentinal caries and periapical inflammatory lesions, visibility of cortical border of the floor and pathological lesions in maxillary sinus were evaluated. Consensus between the observers was considered as reference. Intraobserver agreement was determined. Proportion of equivalent ratings and weighted kappa were used to assess reliability. The level of significance was set to p < 0.05. RESULTS: The proportion of equivalent ratings with consensus differed between uncalibrated and DICOM-calibrated consumer grade displays in dentinal caries in the lower molar in dim lighting (p = 0.021) and between DICOM-calibrated consumer grade and 6-MP display in bright lighting (p = 0.038) for an experienced observer. Significant differences were found between uncalibrated and DICOM-calibrated consumer grade displays in dentinal caries in bright lighting (p = 0.044) and periapical lesions in the upper molar in dim lighting (p = 0.008) for a less experienced observer. Intraobserver reliability was better at detecting dentinal caries than at detecting periapical and maxillary sinus pathology. CONCLUSIONS: DICOM calibration may improve observer performance in panoramic radiography in different lighting conditions. Therefore, a DICOM-calibrated consumer grade display can be used instead of a medical display in dental practice without compromising the diagnostic quality.

Justification of CT examinations in young adults and children can be improved by education, guideline implementation and increased MRI capacity.

OBJECTIVE: To determine whether the justification of CT examinations performed on young patients can be improved by various interventions and whether these have an effect on the total number of CTs performed. METHODS: Specific interventions-education, guideline implementation and increased MRI capacity-were introduced at the Oulu University Hospital, Oulu, Finland, following a previous study demonstrating unjustified use of CT examination in young patients. In the present study, the justification of 177 CT examinations of the lumbar and cervical spine, head, abdomen, nasal sinuses and trauma performed on patients aged under 35 years in 2009 was analysed retrospectively by looking at requests and corresponding patient files. The indications of the examinations were compared with the referral guidelines recommended by the European Commission. Results from our previously published similar study carried out before the interventions were used as a reference. RESULTS: The proportion of justified CT examinations increased from 71% (141/200) in 2005 to 87% (154/177) in 2009 (p<0.001), and in the lumbar spine group from 23% (7/30) to 81% (22/27) (p<0.001). In the case of most of the unjustified examinations, MRI could have been performed instead. The total number of CT examinations carried out on young patients decreased by 7% (p=0.012) and in the lumbar spine group by 79% (p<0.001). CONCLUSION: The implemented interventions decreased the number of CT examinations performed on young patients, and the justification of the examinations improved significantly. ADVANCES IN KNOWLEDGE: This study demonstrates that it is possible to reduce the number of various CT examinations and to improve their justification in young patients by regular education, guideline implementation and increased MRI capacity.

Dual-energy digital radiography in the assessment of bone mechanical properties.

At present, bone fragility and fracture risk are estimated with bone mineral density (BMD), measured by dual-energy x-ray absorptiometry (DXA). It is known that DXA-based BMD (BMD(DXA)) has a relationship with mechanical characteristics of bone. Dual-energy digital radiography (DEDR) has also been shown to be a potential method to determine BMD, but the ability of DEDR-based BMD (BMD(DEDR)) to predict bone mechanical properties is not yet known. In this study, we investigated the ability of BMD(DEDR) to predict the mechanical characteristics of bone. Reindeer femora (N = 50) were imaged at two different energies (79 and 100 kV(p)) using a clinical digital radiography system. BMD was determined in four regions from these images using the DXA calculation principle. Femora were mechanically tested using axial loading configuration. Mechanical parameters were correlated with the BMD(DEDR) and BMD(DXA) of the femoral neck (FNBMD(DEDR) and FNBMD(DXA)). FNBMD(DEDR) and FNBMD(DXA) both correlated moderately with mechanical parameters. The highest correlations were found with maximal load (r = 0.53 and r = 0.65, p < 0.01, respectively). No statistically significant differences were found between the correlation coefficients when comparing the FNBMD(DEDR) or FNBMD(DXA) values and mechanical parameters. The correlation coefficient between BMD(DEDR) and BMD(DXA) varied between r = 0.56 and 0.86 (p < 0.01) in different regions of the upper femur. In conclusion, BMD(DEDR) predicts the mechanical parameters of reindeer bone with similar accuracy as BMD(DXA).

Topographical variation of T2 relaxation time in the young adult knee cartilage at 1.5 T.

OBJECTIVE: To assess the normal topographical variation of T2 relaxation time of articular cartilage in different compartments of the knee joint and at different tissue depths in young healthy adults. METHODS: Twenty asymptomatic young adult volunteers (age range, 21-27 years; mean age, 22.5 years), were studied at 1.5T. Both axial and sagittal multi-slice multi-echo spin echo measurements were performed to determine the T2 relaxation time of cartilage in the femoral, tibial and patellar compartments. The cartilage surfaces were divided into 24 segments and each segment was divided into deep and superficial regions-of-interest (ROIs) of equal thickness. The reproducibility for ROI analysis was assessed for five patients by determining the interclass correlation coefficient (ICC) and the root-mean-square coefficient of variation (CV(RMS)). RESULTS: Cartilage T2 was significantly dependent on joint topography, compartment and tissue depth. For all joint surfaces, superficial T2 values were systematically higher as compared to deep tissue. The data showed a trend toward higher T2 values at the load bearing area of the femoral condyles. The interobserver error varied significantly among different locations and showed mostly good reproducibility with mean ICC of 0.70 and a CV(RMS) of 5.0%. CONCLUSION: The normal variation in cartilage T2 within a joint is significant and should be acknowledged when pathology-related T2 changes are investigated. The knowledge on normal variation can be used for power and sample size calculations in further studies, and the T2 values as control data in future patient studies.

Association of lumbar arterial stenosis with low back symptoms: a cross-sectional study using two-dimensional time-of-flight magnetic resonance angiography.

BACKGROUND: Recent studies indicate that diminished blood flow may cause low back symptoms and intervertebral disc degeneration. PURPOSE: To explore the association between lumbar arterial stenosis as detected by two-dimensional time-of-flight magnetic resonance angiography (2D TOF-MRA) and lumbar pain symptoms in an occupational cohort of middle-aged Finnish males. MATERIAL AND METHODS: 228 male subjects aged 36 to 55 years (mean 47 years) were imaged with 2D TOF-MRA. Additionally, 20 randomly selected subjects were scanned with contrast-enhanced MRA (ceMRA). In each subject, the first (L1) to fourth (L4) segmental lumbar arteries were evaluated for lumbar artery stenosis using a dichotomic scale. One subject was excluded because of poor image quality, reducing the study population to 227 subjects. Logistic regression analysis was used to evaluate the association between arterial stenosis in 2D TOF-MRA and low back pain and sciatica symptoms (intensity, duration, frequency). RESULTS: Comparing 2D TOF-MRA and ceMRA images, the kappa value (95% confidence interval) was 0.52 (0.31-0.73). The intraobserver reliability kappa value for 2D TOF-MRA was 0.85 (0.77-0.92), and interobserver kappa was 0.57 (0.49-0.65). The sensitivity of 2D TOF-MRA in detecting stenosis was 0.58, the accuracy 0.89, and the specificity 0.94. In 97 (43%) subjects all arteries were normal, whereas 130 (57%) had at least one stenosed artery. The left L4 artery was most often affected. The degree of arterial stenosis was associated with intensity of low back and sciatic pain, and sciatica pain duration during the past 3 months. CONCLUSION: 2D TOF-MRA is an acceptable imaging method for arterial stenosis compared to ceMRA. Arterial stenosis was associated with subjective pain symptoms, indicating a role of decreased nutrition in spinal disorders.

Chronic hydrocephalus after neurosurgical and endovascular treatment of ruptured intracranial aneurysms.

BACKGROUND: Chronic hydrocephalus is a common sequela of subarachnoid hemorrhage (SAH). The technical procedure used to treat intracranial aneurysms, whether neurosurgical clipping or endovascular coiling, may lead to differences in the incidence of chronic posthemorrhagic hydrocephalus. PURPOSE: To compare the effects of early neurosurgical and early endovascular treatment on the development of chronic hydrocephalus in patients with SAH. MATERIAL AND METHODS: A retrospective study included 102 clipped and 107 coiled patients with aneurysmal SAH. Clinical condition at admission and shunt dependence were verified from patient data records. The initial and follow-up computed tomography (CT) images were reviewed, and the amount and distribution of blood and the occurrence of hydrocephalus were registered. The values of the cella media index and the width of the third ventricle were calculated. Statistical analysis of the data was performed. RESULTS: No statistically significant differences in the incidence of chronic hydrocephalus or the need for shunting emerged between the treatment groups. After clipping 35% and after coiling 39% of the patients developed chronic hydrocephalus. Twenty-nine percent of the clipped and 31% of the coiled patients underwent a shunt operation. CONCLUSION: The treatment method used for acutely ruptured intracranial aneurysms, i.e., neurosurgical clipping or endovascular coiling, has no statistically significant effect on the development of chronic hydrocephalus.

Quantitative magnetic resonance imaging of experimentally injured porcine intervertebral disc.

BACKGROUND: Changes in T2 relaxation time (T2-TR) and apparent diffusion coefficients (ADC) have been suggested to appear in the intervertebral disc before morphological changes. Such sensitive imaging methods could be beneficial in the targeting and follow-up of intradiscal gene therapy. PURPOSE: To investigate the sensitivity of quantitative magnetic resonance (MR) imaging methods (T2-TR and ADC) in early disc degeneration, using an experimental porcine intervertebral disc injury model, and to investigate their sensitivity in depicting biochemically controlled degenerative changes in the disc. MATERIAL AND METHODS: Six juvenile pigs underwent experimental annular stab incisions, one superficial and one reaching the nucleus pulposus. The animals underwent repeated 1.5T MR imaging and were sacrificed 4 or 8 weeks after operation. Presence of degenerative changes was controlled with biochemical analysis. RESULTS: Discs with full-thickness annular incisions lost 30% of their sagittal mid-slice nucleus pulposus area in 2 weeks (P<0.05). T2-TRs of the respective discs were on average 73% of the control discs (P<0.05). Discs with full-thickness annular lesions showed increased ADC values 4 weeks and reduced ADC values 8 weeks after the operation, compared to control discs (P<0.05). Biochemical analysis showed changes consistent with early degeneration. CONCLUSION: Early traumatic or degenerative changes are detectable with both T2-TR and ADC. The ADC in the early phase after experimental trauma seems to initially increase before decreasing.

Patellar cartilage lesions: comparison of magnetic resonance imaging and T2 relaxation-time mapping.

PURPOSE: To evaluate the detection and the size of focal patellar cartilage lesions in T2 mapping as compared to standard clinical magnetic resonance imaging (MRI) at 1.5T. MATERIAL AND METHODS: Fifty-five consecutive clinical patients referred to knee MRI were imaged both with a standard knee MRI protocol (proton-density-weighted sagittal and axial series, T2-weighted sagittal and coronal series, and T1-weighted coronal series) and with an axial multislice multi-echo spin-echo measurement to determine the T2 relaxation time of the patellar cartilage. MR images and T2 maps of patellar cartilage were evaluated for focal lesions. The lesions were evaluated for lesion width (mm), lesion depth (1/3, 2/3, or 3/3 of cartilage thickness), and T2 value (20-40 ms, 40-60 ms, or 60-80 ms) based on visual evaluation. RESULTS: Altogether, 36 focal patellar cartilage lesions were detected from 20 human subjects (11 male, nine female, mean age 40+/-15 years). Twenty-eight lesions were detected both on MRI and T2 maps, while eight lesions were only visible on T2 maps. Cartilage lesions were significantly wider (P = 0.001) and thicker (P<0.001) on T2 maps as compared to standard knee MRI. Most lesions 27 had moderately (T2 40-60 ms) increased T2 values, while two lesions had slightly (T2 20-40 ms) and seven lesions remarkably (T2 60-80 ms) increased T2 relaxation times. CONCLUSION: T2 mapping of articular cartilage is feasible in the clinical setting and may reveal early cartilage lesions not visible with standard clinical MRI.

Reliability of the evaluation of multidetector computed tomography images from the scanner's console in high-energy blunt-trauma patients.

PURPOSE: To evaluate the reliability of a structured 5-min evaluation of multidetector computed tomography (MDCT) images from the scanner's console in high-energy trauma patients. MATERIAL AND METHODS: Forty patients were scanned with four-slice MDCT using a standardized trauma protocol. Image evaluation covered the thorax, abdomen, and pelvis. The radiologist scrolled axial images on the scanner's console using three different window settings (lung, soft tissue, and bone) and performed a prospective structured evaluation of the traumatic lesions. The findings were compared to the final radiological diagnosis of the MDCT data made on a PACS workstation, the operative findings, and the clinical follow-up. RESULTS: Evaluation from the scanner's console enabled the diagnosis of all potential life-threatening injuries, the sensitivity for all injuries being 60% and specificity 98%. CONCLUSION: A PACS workstation is needed for the final diagnosis of all injuries, but this rapid screening method can reliably detect all injuries that require instant care.

Cost analysis of an open low-field (0.23T) MRI unit: effect of procedure shares in combined imaging, interventional, and neurosurgical use.

PURPOSE: To analyze the cost structure of procedures performed in a multipurpose interventional magnetic resonance imaging (IMRI) unit and to analyze the effect of procedure shares on cost structure. MATERIAL AND METHODS: During a 1-year period, 691 procedures were performed in the IMRI unit, of which 563 were diagnostic MRI examinations, 89 MRI-guided interventions, and 39 MRI-guided neurosurgical operations. Three alternative utilization models of IMRI were created to simulate different local institutions by adjusting the proportions of different procedures. The costs of procedures were calculated by activity-based cost analysis. RESULTS: The cost of the main procedure (imaging, biopsy, injection, or operation) was the most significant item in all procedures, accounting for 66-89% of the total costs. The volume of imaging has a major effect on unit costs. Volume is not such a deterministic factor in interventions due to the high material costs. The volume of neurosurgical use of IMRI has a major effect on the costs of radiological procedures due to the long operation times. CONCLUSION: The volumes of different procedures done on an IMRI unit have significant effects on the unit costs of the procedures.

Magnetic resonance imaging-guided diskography and diagnostic lumbar 0.23T MRI: an assessment study.

PURPOSE: To describe the in vivo appearance of magnetic resonance imaging (MRI) diskograms of normal and degenerated lumbar intervertebral disks, and to evaluate the differences in imaging findings between sequential diagnostic MRI and MRI diskography. MATERIAL AND METHODS: Nine consecutive patients underwent MRI-guided diskography in order to determine possible pain provocation during puncture and contrast medium injection. All patients had preceding clinical suspicion of lumbar diskogenic pain and findings of lumbar disk degeneration in diagnostic (MRI, computed tomography (CT), plain radiography). A 0.23T open MRI scanner with interventional tools was used for imaging and instrument guidance. On all patients, a complementary diagnostic MRI study of the lumbar spine before and after the MRI-guided disk injection was performed, and subsequent axial MRI diskograms were obtained. RESULTS: A total of 25 disk punctures were initialized, and 25 MRI diskograms were obtained and their expression described. There was a correlation between the degenerative disk findings visualized by diagnostic MRI and MRI diskograms. CONCLUSION: The use of gadolinium contrast media in MRI-guided diskography enables the evaluation of MRI diskograms. Our results suggest that MRI-guided diskography can be used to substitute conventional diskography or CT-diskography and as an augmenting method to assess diagnostic information upon degenerative processes of the lumbar spine.

Cost comparison of low-field (0.23 T) MRI-guided laser ablation and surgery in the treatment of osteoid osteoma.

The purpose of this study was to analyze the costs of magnetic resonance imaging (MRI)-guided laser ablation and to compare them with the costs of surgery in the treatment of osteoid osteoma. Seven patients with osteoid osteoma were treated with MRI-guided interstitial laser ablation during 1 year. The reference material consisted of six patients whose osteoid osteoma was treated surgically by either superficial or deep excision with metallic fixation. The costs were analyzed by using activity-based cost accounting. The mean cost of the MRI-guided laser ablation was 2,392 euros and of the excision of superficially located osteoid osteoma 1,807 euros. The cost of excision of deeply located osteoma with metallic fixation was considerably higher (4,996 euros). This was due to the higher material, personnel, and ward costs. The cost of MRI-guided laser ablation of osteoid osteoma was higher than the cost of surgical excision of a superficial osteoma but considerably lower than the cost of excision of a deeply located osteoma where metallic fixation was needed. When the number and mean cost of sick days or days of restricted weight bearing were also included, the cost of MRI-guided laser ablation was lower than the costs of either superficial or deep excision.

MR-guided interventional procedures: a review.

Magnetic resonance imaging (MRI) has emerged as a potential guidance tool for a variety of procedures. Diagnostic and therapeutic procedures using either open surgical or percutaneous access are performed. They span from simple lesion targeting and biopsy to complex applications requiring multiple tasks performed simultaneously or in rapid succession. These tasks include instrument guidance and therapy monitoring as well as procedural follow-up. The interventional use of MRI (IMRI) is increasing steadily. This article reviews the prerequisites, systems, and clinical interventional procedures of IMRI.

Value of multidetector computed tomography in assessing blunt multitrauma patients.

PURPOSE: To find out if multidetector computed tomography (MDCT), using a dedicated trauma protocol, provides sufficient diagnostic information of the injuries of blunt multitrauma patients to enable the planning of treatment for all body compartments. MATERIAL AND METHODS: One-hundred-and-thirty-three patients exposed to high-energy trauma were referred and scanned with the standardized MDCT multitrauma protocol. The imaging protocol consisted of axial scanning of the head and helical scanning of the facial bones, cervical spine, thorax, abdomen, and pelvis. The scanning times were 12 s for the head, 19-21 s for the facial bones and cervical spine (1 mm collimation), and 32-50 s for the thorax, abdomen, and pelvis (2 mm collimation). One-hundred-and-forty milliliters of non-iodinated contrast material (300 mg I/ml) was administered intravenously at 3 ml/s. RESULTS: Ninety-nine of the patients (74%) had at least one finding consistent with trauma. The most frequent findings were in the thorax in 58 patients (44%). Nineteen false-negative findings and two false-positive findings were made. The overall sensitivity of MDCT was 94%, specificity 100%, and accuracy 97%. CONCLUSION: MDCT is accurate in the assessment of blunt multitrauma patients. The decision to treat the patient can be made on the basis of MDCT with a reasonable level of certainty.

MRI-guided abdominal biopsy in a 0.23-T open-configuration MRI system.

The purpose of this study was to test the hypothesis that when ultrasound (US) guidance is not feasible, abdominal biopsies can be performed safely and accurately under magnetic resonance imaging (MRI) guidance in a low-field environment. MRI-guided abdominal biopsy was performed on 31 consecutive patients, in whom US-guided abdominal biopsy was not possible because the lesion was not visualized in US (n=27) or an US-guided procedure was not considered safe (n=4). The locations of the lesions were liver (n=14), pancreas (n=6), lymph node (n=4), retroperitoneal mass (n=3), adrenal gland (n=3) and spleen (n=1). The average size of the lesion was 2.2 cm (range 1-4 cm) in maximum diameter. All procedures were done by using a 0.23-T open-configuration C-arm-shaped MRI scanner with interventional optical tracking equipment and software. Fine-needle aspiration (FNA) biopsy was performed on all 31 patients; 18 patients underwent both FNA biopsy and cutting needle core biopsy. Procedures were evaluated for diagnostic sensitivity, specificity and accuracy as well as procedure time and complications. The FNA biopsy specimens were adequate for interpretation in 27 (87%) of 31 cases. Two of these proved to be false-negative findings during follow-up or subsequent biopsy. The final diagnosis was malignant in 15 and benign in 16 patients. The sensitivity, specificity and accuracy of FNA biopsy were 71, 100 and 81%, respectively. Of the 18 core-needle biopsies, one was determined false-negative owing to nonrepresentativeness. The sensitivity, specificity and accuracy of histological samples were 90, 100 and 94%, respectively. The needle time was 19 min on average and the mean room time was 1 h 48 min. No immediate or late complications occurred. MRI-guided abdominal biopsy can be performed safely and accurately in a low-field environment in patients for whom an US-guided procedure is not feasible.

Contrast-enhanced dynamic and static MRI correlates with quantitative 99Tcm-labelled nanocolloid scintigraphy. Study of early rheumatoid arthritis patients.

OBJECTIVE: The aim of this study was to evaluate the roles of contrast-enhanced dynamic and static magnetic resonance imaging (MRI) and quantitative 99Tcm-labelled nanocolloid (NC) scintigraphy in detecting wrist joint inflammation in early rheumatoid arthritis (RA) patients. METHODS: Twenty-eight early RA patients (median symptom duration 5 months, range 1-12 months) underwent MRI, NC scintigraphy, laboratory and clinical examinations. Static wrist MRI scans were retrospectively scored for synovitis, bone oedema and erosions by two independent readers using the recently published rheumatoid arthritis MRI scoring system (RAMRIS). Twenty NC scans were analysed quantitatively by measuring maximum 99Tcm-NC uptake in three small areas of each wrist. From the same locations on the wrists, dynamic MRI gadolinium-diethylenetriaminepenta-acetic acid (Gd-DTPA) enhancement rates (E-rate) were measured. The average 99Tcm-NC uptake of the whole wrist region was also measured and average E-rates were calculated. Correlations between MRI and NC scintigraphy measurements were calculated. Correlations between imaging methods of the wrist and the global measures of inflammation (laboratory and clinical examinations) were also assessed. RESULTS: Strong correlations emerged between maximal 99Tcm-NC uptake and MRI E-rates, reflecting similar performance of the methods in detecting local synovial inflammation. 99Tcm-NC uptake and MRI E-rate correlated with semiquantitative scoring of synovitis and bone oedema from static MRI scans. The erythrocyte sedimentation rate (ESR) correlated with MRI scores, E-rate and 99Tcm-NC uptake. No correlation between the clinical parameters and the imaging methods was detected. Inter-observer reliability for scoring synovial hypertrophy, bone oedema and bone erosions from static MR images were high (single-measure fixed-effects intra-class correlations 0.87, 0.93 and 0.91 respectively). Intra-observer reliability for E-rate and 99Tcm-NC measurements of 10 randomly picked scans was found to be high, with an intra-class correlation of 0.92; 95% confidence interval (CI) 0.84-0.96 and 0.99; 95% CI 0.98-1.00, respectively. CONCLUSIONS: Objective information about wrist joint inflammation can be obtained with contrast-enhanced dynamic MRI and quantitative 99Tcm-labelled NC scintigraphy. MRI also allows visualization and semiquantitative scoring of bone oedema and erosions of the wrist. Dynamic MRI and NC scintigraphy are safe and easy to perform, and they can be used in a long-term follow-up of rheumatoid patients.