Knee replacement and Diagnosis-Related Groups (DRGs): patient classification and hospital reimbursement in 11 European countries

Purpose

Researchers from 11 countries (Austria, England, Estonia, Finland, France, Germany, Ireland, Netherlands, Poland, Spain, and Sweden) compared how their Diagnosis-Related Group (DRG) systems deal with knee replacement cases. The study aims to assist knee surgeons and national authorities to optimize the grouping algorithm of their DRG systems.

Methods

National or regional databases were used to identify hospital cases treated with a procedure of knee replacement. DRG classification algorithms and indicators of resource consumption were compared for those DRGs that together comprised at least 97 % of cases. Five standardized case scenarios were defined and quasi-prices according to national DRG-based hospital payment systems ascertained.

Results

Grouping algorithms for knee replacement vary widely across countries: they classify cases according to different variables (between one and five classification variables) into diverging numbers of DRGs (between one and five DRGs). Even the most expensive DRGs generally have a cost index below 2.00, implying that grouping algorithms do not adequately account for cases that are more than twice as costly as the index DRG. Quasi-prices for the most complex case vary between €4,920 in Estonia and €14,081 in Spain.

Conclusions

Most European DRG systems were observed to insufficiently consider the most important determinants of resource consumption. Several countries’ DRG system might be improved through the introduction of classification variables for revision of knee replacement or for the presence of complications or comorbidities. Ultimately, this would contribute to assuring adequate performance comparisons and fair hospital reimbursement on the basis of DRGs.

Level of evidence

Retrospective comparative study, Level III.     

Hip imaging of avascular necrosis at 7 Tesla compared with 3 Tesla

Objectives

To compare ultra-high field, high-resolution bilateral magnetic resonance imaging (MRI) of the hips at 7 Tesla (T) with 3 T MRI in patients with avascular necrosis (AVN) of the femoral head by subjective image evaluations, contrast measurements, and evaluation of the appearance of imaging abnormalities.

Materials and Methods

Thirteen subjects with avascular necrosis treated using advanced core decompression underwent MRI at both 7 T and 3 T. Sequence parameters as well as resolution were kept identical for both field strengths. All MR images (MEDIC, DESS, PD/T2w TSE, T1w TSE, and STIR) were evaluated by two radiologists with regard to subjective image quality, soft tissue contrasts, B1 homogeneity (four-point scale, higher values indicating better image quality) and depiction of imaging abnormalities of the femoral heads (three-point scale, higher values indicating the superiority of 7 T). Contrast ratios of soft tissues were calculated and compared with subjective data.

Results

7-T imaging of the femoral joints, as well as 3-T imaging, achieved “good” to “very good” quality in all sequences. 7 T showed significantly higher soft tissue contrasts for T2w and MEDIC compared with 3 T (cartilage/fluid: 2.9 vs 2.2 and 3.6 vs 2.6), better detailed resolution for cartilage defects (PDw, T2w, T1w, MEDIC, DESS?>?2.5) and better visibility of joint effusions (MEDIC 2.6; PDw/T2w 2.4; DESS 2.2). Image homogeneity compared with 3 T (3.9–4.0 for all sequences) was degraded, especially in TSE sequences at 7 T through signal variations (7 T: 2.1–2.9); to a lesser extent also GRE sequences (7 T: 2.9–3.5). Imaging findings related to untreated or treated AVN were better delineated at 3 T (≤1.8), while joint effusions (2.2–2.6) and cartilage defects (2.5–3.0) were better visualized at 7 T. STIR performed much more poorly at 7 T, generating large contrast variations (1.5).

Conclusions

7-T hip MRI showed comparable results in hip joint imaging compared with 3 T with slight advantages in contrast detail (cartilage defects) and fluid detection at 7 T when accepting image degradation medially.     

Bilateral hip imaging at 7 Tesla using a multi-channel transmit technology: initial results presenting anatomical detail in healthy volunteers and pathological changes in patients with avascular necrosis of the femoral head

Objective

To evaluate 7-T MRI of both hips using a multi-channel transmit technology to compensate for inherent B1 inhomogeneities in volunteers and patients with avascular necrosis of the femoral head.

Materials and methods

A self-built, eight-channel transmit-receive coil was utilized for B1 modification at 7 T. Two shim modes (individual shim vs. CP2+ mode) were initially compared and the best shim result was used for all further imaging. Robustness of sequences against B1 inhomogeneities, appearance of anatomic and pathologic changes of the femoral heads of MEDIC, DESS, PD/T2w TSE, T1w TSE, and STIR sequences at 7 T were evaluated in 12 subjects on a four-point scale (1–4): four male volunteers and eight patients (seven males, one female) suffering from avascular necrosis treated by advanced core decompression.

Results

Successful MRI of both femoral heads was achieved in all 12 subjects. CP2+ mode proved superior in ten of 12 cases. DESS proved most robust against B1 inhomogeneity. Anatomical details (labrum, articular cartilage) were best depicted in PDw, MEDIC, and DESS, while for depiction of pathological changes PDw, DESS (0.76 mm³) and T1w were superior.

Conclusions

Our initial results of ultra-high-field hip joint imaging demonstrate high-resolution, high-contrast images with a good depiction of anatomic and pathologic changes. However, shifting areas of signal dropout from the femoral heads to the center of the pelvis makes these areas not assessable. For clinical workflow CP2+ mode is most practical. Seven-Tesla MRI of the hip joints may become a valuable complement to clinical field strengths.     

Diffusion-weighted magnetic resonance imaging of symptomatic nerve root of patients with lumbar disk herniation

Introduction

Diffusion-weighted imaging (DWI) can provide valuable structural information that may be useful for evaluating pathological changes of the lumbar nerve root. Diffusion-weighted magnetic resonance (MR) neurography has recently been introduced as an alternative way to visualize nerves, but to date, quantitative DWI and MR neurography have not been applied to evaluate the pathology of lumbar nerve roots.

Methods

Our purpose was to visualize lumbar nerve roots and to analyze their morphology by MR neurography, and to measure the apparent diffusion coefficient (ADC) of lumbar nerve roots compressed by herniated disks using 1.5-T MR imaging. Ten consecutive patients (median age, 48.0 and range, 20?C72?years) with monoradicular symptoms caused by a lumbar herniated disk and 14 healthy volunteers were studied. Regions of interests were placed on the lumbar roots at dorsal root ganglia (DRG) and distal spinal nerves on DWI to quantify mean ADC values. The spinal nerve roots were also visualized by MR neurography.

Results

In the patients, mean ADC values were significantly greater in the compressed DRG and distal spinal nerves than in intact nerves. MR neurography also showed abnormalities such as nerve swelling at and below the compression in the symptomatic nerve root. Increased ADC values were considered to be because of edema and Wallerian degeneration of compressed nerve roots.

Conclusion

DWI is a potential tool for analysis of the pathophysiology of lumbar nerve roots compressed by herniated disks.     

MRI in the assessment of muscular pathology: a comparison between limb-girdle muscular dystrophies, hyaline body myopathies and myotonic dystrophies

Purpose

The continuous discovery of new subtypes of neuromuscular disorders demands more accurate imaging analyses. We set out to establish the specific patterns of muscular involution using magnetic resonance imaging (MRI).

Materials and methods

A systematic clinical evaluation based on the Medical Research Council scale and MRI was completed in ten patients with calpainopathy [limb-girdle muscular dystrophy (LGMD)-2A], 16 with dysferlinopathy (LGMD-2B), ten with hyaline body myopathy (HBM), six with myotonic dystrophy (MD) types 1 and 5 with MD type 2. Severity of fibroadipose degeneration was specifically staged using T1-weighted sequences. Turbo inversion recovery magnitude (TIRM) sequences were used to assess oedema-like changes.

Results

T1 scans showed recurrent patterns of fibroadipose replacement, whereas TIRM images revealed differences in oedema-like changes between the various diseases. In LGMD, the posterior compartments are more vulnerable to degeneration. In HBM, fatty muscle degeneration and oedema are allocated to muscles of the posterior compartments of the leg. In MD, fatty muscle degeneration and oedematous changes are allocated to muscles of the anterior thigh and posterior lower leg.

Conclusions

Imaging examination suggests a characteristic pattern of muscle involvement. MRI represents an important diagnostic technique useful in differential diagnosis, thanks to the distinctive patterns observed in the distribution of muscular changes between the different muscular diseases.     

Clinical validation of semi-automated software for volumetric and dynamic contrast enhancement analysis of soft tissue venous malformations on Magnetic Resonance Imaging examination

Objectives

To evaluate venous malformation (VM) volume and contrast-enhancement analysis on magnetic resonance imaging (MRI) compared with diameter evaluation.

Methods

Baseline MRI was undertaken in 44 patients, 20 of whom were followed by MRI after sclerotherapy. All patients underwent short-tau inversion recovery (STIR) acquisitions and dynamic contrast assessment. VM diameters in three orthogonal directions were measured to obtain the largest and mean diameters. Volumetric reconstruction of VM was generated from two orthogonal STIR sequences and fused with acquisitions after contrast medium injection. Reproducibility (interclass correlation coefficients [ICCs]) of diameter and volume measurements was estimated. VM size variations in diameter and volume after sclerotherapy and contrast enhancement before sclerotherapy were compared in patients with clinical success or failure.

Results

Inter-observer ICCs were similar for diameter and volume measurements at baseline and follow-up (range 0.87–0.99). Higher percentages of size reduction after sclerotherapy were observed with volume (32.6?±?30.7 %) than with diameter measurements (14.4?±?21.4 %; P?=?0.037). Contrast enhancement values were estimated at 65.3?±?27.5 % and 84?±?13 % in patients with clinical failure and success respectively (P?=?0.056).

Conclusions

Venous malformation volume was as reproducible as diameter measurement and more sensitive in detecting therapeutic responses. Patients with better clinical outcome tend to have stronger malformation enhancement.

Key points

? Magnetic resonance imaging readily demonstrates diameters and volumes of venous malformations ? MRI diameter calculations are reproducible in estimating the size of venous malformations ? But volumetric models of malformations are more sensitive in detecting therapeutic response ? Dynamic enhancement is also better assessed with automated volumetric software ? Volumetric analysis of malformations offers promise to guide therapy and assess response     

Magnetic resonance 4D flow characteristics of cerebrospinal fluid at the craniocervical junction and the cervical spinal canal

Objectives

To evaluate the applicability of 4D phase contrast (4D PC) MR imaging in the assessment of cerebrospinal fluid dynamics in healthy volunteers and patients with lesions at the craniocervical junction or the cervical spinal canal.

Methods

Ten healthy volunteers and four patients with lesions including Chiari I malformation and cervical canal stenoses were examined by a cardiac-gated 4D PC imaging sequence on 1.5T MRI. Phase contrast images were postprocessed allowing for flow quantification and flow pathline visualisation. Velocity data were compared with conventional axial 2D phase contrast images.

Results

The 4D PC sequence allowed for flow quantification and visualisation in all individuals. Bland-Altman analysis showed good agreement of 2D and 4D PC velocity data. In healthy volunteers, CSF flow was homogeneously distributed in the anterior and anterolateral subarachnoid space with the flow directed caudally during systole and cranially during diastole. Flow velocities were closely related to the width of the subarachnoid space. Patients showed grossly altered CSF flow patterns with formation of flow jets with increased flow velocities.

Conclusions

4D PC MR imaging allows for a detailed assessment of CSF flow dynamics helping to distinguish physiological from complex pathological flow patterns at the craniocervical junction and the cervical spine.     

Size, shape and age-related changes of the mandibular condyle during childhood

Objective

To determine age-related differences in the size and shape of the mandibular condyle in children to establish anatomical reference values.

Methods

A total of 420 mandibular condyles in 210 children (mean age, 7 years) were retrospectively analysed by using computed tomography (CT) imaging. The greatest left–right (LRD) and anterior–posterior (APD) diameters and the anteversion angles (AA) were measured by two readers. An APD/LRD ratio was calculated. The shape of the condyles was graded into three types on sagittal images. Correlations of parameters with the children’s age were assessed by using Pearson’s correlation analyses.

Results

The LRD (mean, 14.1?±?2.4 mm), APD (mean, 7.3?±?1.0 mm) and LRD/APD ratio (mean, 1.9?±?0.3) increased (r _LRD?=?0.70, p?<?0.01; r _APD?=?0.56, p?<?0.01; r _rat?=?0.28, p?<?0.01) while the AA (mean, 27?±?7°) decreased significantly (r _antang?=??0.26, p?<?0.001) with age. The condylar shape as determined on sagittal images correlated significantly with age (r?=?0.69, p?<?0.05). Boys had significantly higher anteversion angles (p?<?0.01), greater LRDs (p?<?0.05) and greater mean ratios (p?<?0.05).

Conclusion

The mandibular condyle is subject to significant age-related changes in size and shape during childhood. As the size of the condyles increases with age, the anteversion angles decrease and the shape of the condyle turns from round to oval.     

Assessment of left main coronary artery atherosclerotic burden using 64-slice CT coronary angiography: correlation between dimensions and presence of plaques

Purpose

The aim of this study was to correlate left main (LM) coronary artery dimensions with the presence of atherosclerosis by multidetector-row computed tomography (MDCT) coronary angiography (CA) and to assess coronary atherosclerotic plaques with a semiquantitative method.

Materials and methods

Sixty-two consecutive patients (41 men, mean age 60±11) with suspected coronary artery disease underwent 64-MDCT coronary angiography. LM dimensions (length, ostial and bifurcation diameters), quantitative [location, Hounsfield unit (HU) attenuation] and qualitative (composition, shape) analysis of plaques within the LM were performed. All patients underwent conventional CA.

Results

Thirty patients (mean age 55±10) without plaques in the LM presented the following average dimensions: length 10.6±6.1 mm, ostial diameter 5.5±0.7 mm, bifurcation diameter 4.9±0.9 mm. LM plaques (n=36) were detected in 32 patients (mean age 64±10) with the following LM average dimensions: length 11.3±4.0 mm, ostial diameter 6.0±1.2 mm and bifurcation diameter 6.0±1.2 mm. Plaques were calcified (40%, mean attenuation 742±191 HU), mixed (43%, mean attenuation 387±94 HU) or noncalcified (17%, mean attenuation 56±14 HU) and were frequently eccentric (77%). Age was significantly different in the two groups (p<0.05). LM diameters of patients with plaques were improved (p<0.05). A moderate correlation was found between the LM bifurcation diameter and the corresponding plaque area (r=0.56). Significant conventional CA lesions of the LM were present in just three patients (5%).

Conclusions

Increased LM diameters are associated with the presence of atherosclerosis. MDCT CA indicates relevant features of LM atherosclerotic burden, as rupture and subsequent thrombosis of vulnerable plaques may develop from lesions characterised as nonsignificant at conventional CA.     

Role of multislice computed tomography in the diagnosis of gene-mutation-associated pancreatitis (GMAP)

Purpose

The aim of this study was to review the computed tomography (CT) features of the pancreatic parenchyma and ducts in patients with gene-mutation-associated pancreatitis (GMAP).

Materials and methods

Twenty-five patients with GMAP were included in this retrospective study. Patients were divided into two groups according to the time interval between the onset of symptoms and the first CT examination (group A ≤24 months and group B >25 months).

Results

On qualitative image assessment, in group A patients, pancreatic duct stones were detected in 2/13 with GMAP. All stones were calcified and homogenous. Enhancement of the pancreatic parenchyma was hypovascular in 7/13 patients. In group B patients, pancreatic duct stones were detected in 12/12 with GMAP. Stones were calcified in 10/12 cases and noncalcified (protein plugs) in 2/12; in 5/10 cases, the calcified stones were heterogeneous with noncalcified central core (bull’s-eye appearance). Enhancement of the pancreatic parenchyma was hypovascular in 12/12 patients. On quantitative image assessment, in group A patients, the mean diameter of duct stones was 0.6 mm (range 0–5 mm). Mean diameter of the main duct in the pancreatic head and body/tail was 4.8 mm and 4.9 mm, respectively. In group B patients, the mean diameter of duct stones was 21.9 mm (range 2–50 mm). Mean diameter of the main duct in the pancreatic head and body/tail was 18.8 mm and 13.9 mm, respectively.

Conclusions|

In patients with GMAP and time interval between symptom onset and first CT scan ≤24 months (group A), CT identified normal or slightly increased parenchymal thickness and a main pancreatic duct of normal calibre and without duct stones. In contrast, in patients with GMAP and time interval between symptom onset and first CT scan >25 months (group B), it identified large-calibre duct stones with bull’s-eye appearance.     

Laparoscopic sentinel lymph node (SLN) versus extensive pelvic dissection for clinically localized prostate carcinoma

Purpose

Lymph node metastasis is an important prognostic factor in prostate cancer (PC). The aim of this prospective study was to evaluate the accuracy of sentinel lymph node (SLN) biopsy by laparoscopy in staging locoregional patients with clinically localized PC.

Methods

A transrectal ultrasound-guided injection of 0.3?ml/100?MBq ^99mTc-sulphur rhenium colloid in each prostatic lobe was performed the day before surgery. Detection was performed intraoperatively with a laparoscopic probe (Gamma Sup CLERAD?) followed by extensive resection. SLN counts were performed in vivo and confirmed ex vivo. Histological analysis was performed by haematoxylin-phloxine-saffron staining, followed by immunohistochemistry (IHC) if the SLN was free of metastasis.

Results

The study included 93 patients with PC at intermediate or high risk of lymph node metastases. The intraoperative detection rate was 93.5% (87/93). Nineteen patients had lymph node metastases, nine only in SLN. The false-negative rate was 10.5% (2/19). The internal iliac region was the primary metastatic site (43.3%). Metastatic sentinel nodes in the common iliac region beyond the ureteral junction were present in 13.3%. Limited or standard lymph node resection would have ignored 73.2 and 56.6% of lymph node metastases, respectively.

Conclusion

Laparoscopy is suitable for broad identification of SLN metastasis, and targeted resection of these lymph nodes significantly limits the risk of extended surgical resection whilst maintaining the accuracy of the information.     

Multifocal branch-duct intraductal papillary mucinous neoplasms (IPMNs) of the pancreas: magnetic resonance (MR) imaging pattern and evolution over time

Purpose

The aim of our study was to follow the evolution over time of multifocal intraductal papillary mucinous neoplasms (IPMN) of the pancreatic duct side branches by means of magnetic resonance imaging (MRI).

Materials and methods

A total of 155 patients with multifocal IPMN of the side branches were examined with MRI and MR cholangiopancreatography (MRI/MRCP). Inclusion criteria were patients with ≥2 dilated side branches involving any site of the parenchyma; presence of communication with the main pancreatic duct and previous investigations by MRI/MRCP within at least six months. Median follow-up was 25.8 months (range, 12–217). Patients with a follow-up period shorter than 12 months (n=33) and those with a diagnosis of multifocal IPMN of the side branches without any follow-up (n=14) were excluded from the study. The final study population thus comprised 108 patients. A double, quantitative and qualitative, analysis was carried out. The quantitative image analysis included: number of dilated side branches in the head-uncinate process and body-tail; maximum diameter of lesions in the head-uncinate process; maximum diameter in the body-tail; maximum diameter of the main pancreatic duct in the head and body-tail. The qualitative image analysis included: presence of malformations or anatomical variants of the pancreatic ductal system; site of the lesions (head-uncinate process, body-tail, ubiquitous, bridge morphology); presence of gravity-dependent intraluminal filling defects; presence of enhancing mural nodules.

Results

At diagnosis, the mean number of cystic lesions of the side branches was 7.09. The mean diameter of the cystic lesions was 13.7 mm. The mean diameter of the main pancreatic duct was 3.6 mm. At follow-up, the mean number of cystic lesions was 7.76. The mean diameter of the cystic lesions was 13.9 mm. The mean diameter of the main pancreatic duct was 3.7 mm. Intraluminal filling defects in the side branches were seen in 18/108 patients (16.6%); enhancing mural nodules were seen in 3/108 patients (2.7%).

Conclusions

Multifocal IPMN of the branch ducts shows a very slow growth and evolution over time. In our study, only 3/108 patients showed mural nodules which, however, did not require any surgical procedure, indicating that careful nonoperative management may be safe and effective in asymptomatic patients.     

Follow-up CT and MR findings of osteoblastic spinal metastatic lesions after stereotactic radiotherapy

Purpose

We retrospectively analyzed pre and post-stereotactic radiotherapy CT and MRI findings and volume changes for osteoblastic spinal metastatic lesions.

Materials and methods

Of 114 lesions in 72 patients, 11 were osteoblastic. CT and MR images were reviewed to determine tumor volume, CT attenuation, T2 signal intensities, and contrast enhancement.

Results

Tumor volume did not change for 10 lesions and increased for 1 lesion. CT attenuation increased for 8 lesions with heterogeneous T2 signal intensities. Of these 8 lesions, 4 had patterns of dark signal foci and the other 4 had patterns of both dark and bright signal foci. T2 signal intensity became heterogenous, with dark and bright foci, for 2 of 3 lesions for which CT attenuation decreased, and normalized for the third lesion. The degree of contrast enhancement decreased for 6 lesions and did not change for 5 lesions.

Conclusion

There were no changes in volume except for one case. On CT images, sclerotic changes were more common than loss of sclerotic foci. On T2-weighted images, dark signal intensities with or without bright signal foci developed and the degree of enhancement decreased for more than half of the cases.     

MRI of the ankle joint in healthy non-athletes and in marathon runners: image quality issues at 7.0 T compared to 1.5 T

Objective

To present imaging characteristics of the ankle at 7.0 T and to investigate the appearance and image quality of presumed pathologies of ankles without physical strain as well as of ankles after a marathon run in comparison to 1.5 T.

Materials and methods

Appearance of presumed pathologic findings and image quality of TSE (PD, T2, and STIR) and GRE sequences (MEDIC, DESS, and/or CISS) at 7.0 T and 1.5 T MRI were compared by two senior radiologists in consensus in two healthy controls without strain and in six marathon runners after a full-length marathon (eight males, mean age 49.1 years).

Results

Overall, 7.0 T MRI allowed for higher resolution images for most of the sequences while requiring comparable acquisition times and achieving high contrast images mainly in gradient echo sequences. Bursal or presumed peritendineal fluid and/or edematous tissue, which were found in seven of eight subjects, could be best appreciated with 7.0 T MEDIC. Other findings with sharper delineation at 7.0 T included cartilage defects (best: CISS), osseous avulsions, and osteophytes (best: DESS). Nevertheless, 1.5 T STIR imaging enabled assessment of a tibiotalar bone edema-like lesion in two runners, which was barely visible at 7.0 T using STIR, but not with any other sequence at 7.0 T including MEDIC (with frequency selective fat suppression). 7.0 T showed larger image quality variations with challenges especially in the TSE sequences.

Conclusion

Our initial results of ultra-high-field ankle joint imaging demonstrate the improved depiction of ankle anatomy, fluid depositions, and cartilage defects. However imaging of edema-like bone lesions remains challenging at ultra-high magnetic field strength, and TSE coverage in particular is limited by the specific absorption rate.     

Factors predicting hamstring tendon autograft diameters and resulting failure rates after anterior cruciate ligament reconstruction

Purpose

The purposes of this study are to confirm factors that affect the diameter of hamstring tendon autograft and to compare failure rates between the factors after anterior cruciate ligament (ACL) reconstruction.

Methods

A total of 296 patients that underwent reconstruction using hamstring tendon autograft at our clinics for ACL injury between September 2005 and June 2008 were enrolled for this study. The diameters of gracilis and semitendinosus tendons (harvested from the affected knee) and four-strand graft tendon made by folding the gracilis and semitendinosus tendons in two layers were measured. Before operating, we recorded the age, height, weight, Body Mass Index (BMI), gender and athlete versus non-athlete identity of the subjects and checked their correlations with graft diameters. Patients that recorded a grade C or D on the International Knee Documentation Committee Knee Examination Form, as well as patients that underwent revision, were defined as failures and analysed by related factors.

Results

The mean diameter was 1.5 mm ± 0.2 for gracilis tendon, 2.2 mm ± 0.3 for semitendinosus tendon and 7.2 mm ± 0.7 for graft tendon. Except for age, factors including height, weight, BMI, gender and athlete versus non-athlete identity were found to be significantly related to graft diameter. Correlation was strongest with height (p < 0.001). With respect to failure rates after ACL reconstruction, patients with a graft diameter of 8.0 mm or more demonstrated statistically better results than patients with a diameter of below 8.0 mm (p = 0.043). However, failure rates did not differ significantly with respect to other factors.

Conclusions

The diameter of hamstring tendon autograft may be different depending on height, weight, BMI and gender of the patient, as well as whether or not the patient is an athlete. Although we did not find statistically significant differences in failure rates after ACL reconstruction, this study demonstrated relatively better results in patients with a graft diameter of 8.0 mm or more.

Level of evidence

Case series, Level IV.     

Prognostic value of MDCT in malignant large-bowel obstructions

Purpose

This study aimed to correlate multidetector-row computed tomography (MDCT) findings and postoperative prognosis in malignant large-bowel obstructions.

Materials and methods

Twenty-seven patients affected by malignant colonic obstruction underwent MDCT examination and were analysed for obstruction site, colon-wall morphology, intestinal content alterations and transverse diameter of ascending colon.

Results

Obstruction site was recognised in all cases (5/27 ascending colon; 1/27 transverse colon; 11/27 descending colon; 10/27 sigma-rectum). Intestinal content consisted of mainly air in 3/27 patients, mainly fluid in 11/27 and air-fluid levels in 13/27. In 9/27 cases, pneumatosis intestinalis was found. Mean maximum diameter of the ascending colon was 8.2 cm. Overall mortality rate was 37%. An intestinal content mainly consisting of air (3/3 living patients) or fluid (7/11 living patients) were indicative of good prognosis. Air-fluid level detection indicated poor prognosis in 7/13 cases. Pneumatosis intestinalis (7/9 deceased patients) and ascending colon diameter values ≥10 cm (7/7 deceased patients) were indicative of poor prognosis.

Conclusions

MDCT can identify the presence and site of malignant large-bowel obstructions and may provide useful prognostic information.     

Magnetic resonance imaging features of the spinal cord in pediatric multiple sclerosis: a preliminary study

Introduction

Spinal cord lesions in adults with multiple sclerosis (MS) are thought to contribute to disability. The magnetic resonance imaging (MRI) appearance and clinical correlates of spinal cord lesions in children with MS have not been reported.

Methods

T1-weighted pre- and post-gadolinium and T2-weighted TSE/FSE spine MR images of 36 children (age, 14.3?±?3.3) with relapsing–remitting MS (annualized relapse rate, 0.7; disease duration, 7.5?±?3.3 years) were analyzed for total lesion count, lesion location and length, intramedullary extent, and gadolinium enhancement. Clinical, demographic, laboratory, and MRI data were correlated.

Results

Lesions preferentially involved the cervical region, were predominantly focal, and involved only a portion of the transverse cord diameter. However, ten of 36 patients demonstrated longitudinally extensive lesions. Children with the highest clinical relapse rate also tended to have more spinal cord lesions and were more likely to accrue new lesions on serial spinal scans.

Conclusion

These preliminary data suggest that MS lesions of the spinal cord in children are radiographically similar to that of adult-onset MS—supporting a common biology of pediatric- and adult-onset disease. However, children with relapsing–remitting MS can also develop longitudinally extensive lesions, suggesting that such lesions may be less specific for diseases such as neuromyelitis optica in pediatric patients. All patients recovered well from spinal cord attacks, and the presence of spinal cord lesions in the first few years of disease did not correlate with physical disability. Measures of spinal cord atrophy and longer periods of observation are required to determine the impact of spinal cord involvement in pediatric-onset MS.     

CT angiography after carotid artery stenting: assessment of the utility of adaptive statistical iterative reconstruction and model-based iterative reconstruction

Introduction

Follow-up CT angiography (CTA) is routinely performed for post-procedure management after carotid artery stenting (CAS). However, the stent lumen tends to be underestimated because of stent artifacts on CTA reconstructed with the filtered back projection (FBP) technique. We assessed the utility of new iterative reconstruction techniques, such as adaptive statistical iterative reconstruction (ASIR) and model-based iterative reconstruction (MBIR), for CTA after CAS in comparison with FBP.

Methods

In a phantom study, we evaluated the differences among the three reconstruction techniques with regard to the relationship between the stent luminal diameter and the degree of underestimation of stent luminal diameter. In a clinical study, 34 patients who underwent follow-up CTA after CAS were included. We compared the stent luminal diameters among FBP, ASIR, and MBIR, and performed visual assessment of low attenuation area (LAA) in the stent lumen using a three-point scale.

Results

In the phantom study, stent luminal diameter was increasingly underestimated as luminal diameter became smaller in all CTA images. Stent luminal diameter was larger with MBIR than with the other reconstruction techniques. Similarly, in the clinical study, stent luminal diameter was larger with MBIR than with the other reconstruction techniques. LAA detectability scores of MBIR were greater than or equal to those of FBP and ASIR in all cases.

Conclusion

MBIR improved the accuracy of assessment of stent luminal diameter and LAA detectability in the stent lumen when compared with FBP and ASIR. We conclude that MBIR is a useful reconstruction technique for CTA after CAS.     

The use of axial diameters and CT obstruction scores for determining echocardiographic right ventricular dysfunction in patients with acute pulmonary embolism

Purpose

To evaluate the accuracy of cardiac computed tomography (CT) parameters and pulmonary artery (PA) obstruction (OS) scores in determining the echocardiographic right ventricular dysfunction (RVD) in hemodynamically stable patients with acute pulmonary embolism (PE).

Materials and methods

A total of 120 patients with acute PE were included in the study. Right ventricle/left ventricle ratio (RV/LV); PA axial diameter; superior vena cava (SVC) axial diameter; and Ghanima, Miller, Qanadli, and Mastora obstruction scores were obtained using CT. RVD was assessed by echocardiography. The patients were divided into two groups based on the presence or absence of RVD.

Results

RV/LV ratio, SVC axial diameter, PA axial diameter, and Miller, Qanadli, and Mastora scores were significantly increased in the RVD group. Multivariate logistic regression analysis showed that RV/LV ratio [OR 6.36 (2.02–279.46 95 % CI), p = 0.01] and PA axial diameter [OR 5.02 (1.02–1.26 95 % CI), p = 0.03] were independent predictors of echocardiographic RVD. Predictive values of these parameters were improved when combined with other intragroup cutoff values. A cutoff value for the RV/LV ratio of >1.08 had 81.43 % sensitivity, 52.08 % specificity, 71.3 PPV, and 65.8 NPV for prediction of RVD.

Conclusion

Tomographic axial diameters enable more accurate predictions of RVD than OS scores do.     

Maximum Diameter Measurements of Aortic Aneurysms on Axial CT Images After Endovascular Aneurysm Repair: Sufficient for Follow-up?

Purpose

To assess the accuracy of maximum diameter measurements of aortic aneurysms after endovascular aneurysm repair (EVAR) on axial computed tomographic (CT) images in comparison to maximum diameter measurements perpendicular to the intravascular centerline for follow-up by using three-dimensional (3D) volume measurements as the reference standard.

Materials and Methods

Forty-nine consecutive patients (73?±?7.5?years, range 51?C88?years), who underwent EVAR of an infrarenal aortic aneurysm were retrospectively included. Two blinded readers twice independently measured the maximum aneurysm diameter on axial CT images performed at discharge, and at 1 and 2?years after intervention. The maximum diameter perpendicular to the centerline was automatically measured. Volumes of the aortic aneurysms were calculated by dedicated semiautomated 3D segmentation software (3surgery, 3mensio, the Netherlands). Changes in diameter of 0.5?cm and in volume of 10% were considered clinically significant. Intra- and interobserver agreements were calculated by intraclass correlations (ICC) in a random effects analysis of variance. The two unidimensional measurement methods were correlated to the reference standard.

Results

Intra- and interobserver agreements for maximum aneurysm diameter measurements were excellent (ICC?=?0.98 and ICC?=?0.96, respectively). There was an excellent correlation between maximum aneurysm diameters measured on axial CT images and 3D volume measurements (r?=?0.93, P?r?=?0.93, P?Conclusion Measurements of maximum aneurysm diameters on axial CT images are an accurate, reliable, and robust method for follow-up after EVAR and can be used in daily routine.