Gadolinium-enhanced magnetic resonance angiography, colour duplex and digital subtraction angiography of the lower limb arteries from the aorta to the tibio-peroneal trunk in patients with intermittent claudication.

OBJECTIVES: To evaluate the sensitivity, specificity, positive and negative predictive value of contrast-enhanced (gadolinium) magnetic resonance imaging (CE-MRA) and colour duplex ultrasound (CDU) of lower limb arteries. DESIGN: Prospective, single centre study. MATERIAL AND METHODS: A consecutive series of 58 patients with intermittent claudication (IC) were examined with CE-MRA and CDU from the infrarenal aorta to the tibio-peroneal trunk with digital subtraction angiography (DSA) as reference. The arterial tree was divided into 15 segments, pooled into three regions; suprainguinal, thigh and knee. Sensitivity, specificity, positive and negative predictive values for significant obstructions were calculated. Cohen Kappa statistics was used to establish agreement between the three methods. RESULTS: The sensitivity (specificity in parentheses) for significant obstructions in the suprainguinal region were 96% (94%) for CE-MRA and 91% (96%) for CDU, in the thigh region 92% (95%) for CE-MRA and 76% (99%) for CDU, and in the knee region 93% (96%) for CE-MRA and 33% (98%) for CDU. CDU failed to visualize 10% of suprainguinal, 2% of thigh and 13% of knee-region arterial segments. CONCLUSIONS: Both CE-MRA and CDU are good alternatives to DSA in the suprainguinal- and thigh-region. In the knee region only CE-MRA can be relied upon as an alternative to DSA. Imaging by CDU is not suited to situations were evaluation of runoff vessels is important.

Anastomotic leak following mesorectal excision for rectal cancer: true incidence and diagnostic challenges.

OBJECTIVE: Anastomotic leakage is a potentially serious complication of low anterior resection which may be accompanied by clinical symptoms (clinical leak) or may be silent (subclinical leak). In this study the true incidence of the complication was evaluated, and the diagnostic accuracy of clinical symptoms, conventional rectal radiography (CRR) and computed tomography (CT) was compared. PATIENTS AND METHODS: Fifty-six consecutive patients were included in a prospective trial. Clinical parameters were recorded and CRR and CT performed 6-10 days postoperatively or earlier if a leak was suspected. Endoscopy was performed three months postoperatively. RESULTS: Based on all available information including late endoscopy, 5 (9%) patients had clinical leak and five a leak that was asymptomatic during the hospital stay. Clinical assessment, CRR and CT during the hospital stay had an accuracy of 82%, 93% and 94%, respectively, and a sensitivity of 50%, 60% and 57%, respectively. The specificity of clinical assessment was 89%, whereas both CRR and CT had a specificity of 100%. CONCLUSION: The incidence of anastomotic leakage seemed acceptable when compared with other series. Fifty per cent of the leaks were silent. CRR and CT may be false negative and immediate treatment should be started if clinical signs are highly suggestive of leak, irrespective of radiological findings CT was not more accurate than CRR in detecting anastomotic leak.

Conventional and diffusion-weighted MRI in the evaluation of methanol poisoning.

Cerebral lesions were studied in 2 methanol-poisoned patients using conventional magnetic resonance imaging (MRI). In 1 patient, diffusion-weighted MRI (DWI) was also performed. In this patient, conventional MRI showed symmetrical, bilateral increased signal in the lentiform nuclei, involving predominantly putamina, but also extending into the corona radiata, centrum semiovale and subcortical white matter. DWI showed decreased diffusion, which most probably reflects cytotoxic edema. In the other patient, fluid attenuated-inversion recovery (FLAIR) and T2-weighted images showed hyperintensity in the putamina, characteristic of post-necrotic changes.

MR imaging of ventriculus terminalis of the conus medullaris. A report of two operated patients and a review of the literature.

We report on 2 patients in whom a cystic dilation of the conus medullaris was incidentally found at MR imaging carried out in the work-up for sciatica. The cysts were well circumscribed and had signal intensity identical to the CSF on both T1- and T2-weighted images. There was no evidence of contrast enhancement. None of the patients had specific symptoms related to the spinal cord. At surgery, no evidence of malignancy was seen in any of the patients. A benign cystic dilation, also called dilated ventriculus terminalis, occasionally can be seen in the conus medullaris as an incidental finding at thoracolumbar MR imaging. Unless the expansion per se indicates cyst drainage, these patients may be monitored by clinical and MR follow-up, avoiding surgery in a substantial number of cases.

Accuracy of CT scan measurements of the medial temporal lobe in routine dementia diagnostics.

BACKGROUND: Atrophy of the medial part of the temporal lobe is seen in Alzheimer's disease (AD). We studied the usefulness of CT scan measurements of the medial temporal lobe (MTL) in elderly with suspected dementia. METHODS: MTL measurements were done with callipers by three raters, blinded to the diagnosis and to each other, on scans from 110 subjects with suspected dementia from a memory clinic in Oslo, Norway and 36 participants included in the OPTIMA study, Oxford, England. RESULTS: The correlation between the MTL and the Mini-Mental State Examination (MMSE) was very low, and there was a marked overlap between Alzheimer and cognitively unimpaired subjects. The inter-rater reliability was lower on the Norwegian than on the OPTIMA scans (R = 0.48 vs R = 0.68), but this was partly explained by larger MTL readings (4.5 mm after adjustment for age, gender and MMSE sumscore) on the OPTIMA scans as the reliability was confounded by MTL width and was higher at larger MTLs. A wider scan width (3 mm vs 2 mm in the OPTIMA scans) can also contribute to differences in reliability. CONCLUSIONS: The published threshold values regarding the CT scan MTL measurements for the diagnosis of AD may be invalid when applied by other radiology departments without a local standardisation and validation.

Post-traumatic cerebral infarction. Neuroimaging findings, etiology and outcome.

PURPOSE: To assess the radiological characteristics of post-traumatic cerebral infarctions (PTCIs), the etiology and site of infarction, and to provide neuroimaging indicators of a poor clinical outcome. MATERIAL AND METHODS: A retrospective study of 16 patients with the neuroimaging-based diagnosis of PTCI was carried out. All CT, MR examinations, cerebral angiograms and medical records of the patients were reviewed. RESULTS: Infarcts were diagnosed in the territory of the posterior cerebral artery in 9 patients, in the middle cerebral artery in 5, in the anterior cerebral artery in 3, lenticulostriate-thalamoperforating in 2, vertebrobasilar in 3, and cortical infarcts in 2 patients. Neuroimaging studies suggested focal mass effect and/or acquired intracranial herniations as the cause of infarction in 13/16 patients (81.2%). In 3/16 patients (18.8%), PTCI was due to vascular injury of which 2 were angiographically documented (carotid artery dissection). Eight of the 16 patients in this study died or were left in a persistent vegetative state. Patients with associated subdural hematoma, brain swelling/edema and traumatic subarachnoid hemorrhage (tSAH) exhibited the worst outcome. CONCLUSION: Gross mechanical shift of the brain and herniation across the falx and/or tentorium accounted for infarction in a majority of cases in our study. The overall death rate was 43.8% and this result suggests that PTCI is an indication of a poor clinical outcome, especially among patients with associated subdural hematoma, brain swelling/edema and tSAH.

Unawareness of illness in chronic schizophrenia and its relationship to structural brain measures and neuropsychological tests.

The present study seeks to elucidate the relationship between unawareness of illness in schizophrenia and frontal lobe dysfunction, in addition to investigating the relationship between lack of insight and sociodemographic and clinical variables. Twenty-one medicated schizophrenic patients, recruited from in- and out-patient wards at Ullevâl Hospital, underwent the Scale to Assess Unawareness of Mental Disorder (SUMD), neuropsychological testing, psychiatric symptom ratings and neuroimaging procedures (CT). Also, 21 matched normal controls were neuropsychologically tested. CT data were assessed blindly by two experienced neuroradiologists, according to the degree of ventricular enlargement and/or sulcal widening, and an assessment of localisation of atrophy was made. Unawareness of illness was correlated with neuropsychological measures related to executive functioning, but not with other neuropsychological measures. Five patients showed slight frontal atrophy, while two showed moderate frontal atrophy. The remaining 13 patients did not show signs of frontal lobe atrophy. Frontal lobe atrophy documented by structural brain measures was associated with poor insight in schizophrenia. Furthermore, Anergia (BPRS), GAF score and 'undifferentiated' sub-diagnosis correlated with SUMD scores. Unawareness of illness in schizophrenia may be related to frontal lobe deficit. Also, awareness of illness may not be related to general psychopathology, but rather to specific aspects.

Postoperative nerve root displacement and scar tissue. A prospective cohort study with contrast-enhanced MR imaging one year after microdiscectomy.

PURPOSE: To investigate the association between postoperative nerve root displacement and epidural scar tissue. MATERIAL AND METHODS: One hundred patients who had undergone lumbar microdiscectomy were included in a prospective cohort study with a 1-year follow-up. The patients were classified as failures or successes at the 12-month follow-up according to a clinical score. Patients with signs of recurrent disc herniation on MR were excluded from the study. All the 13 patients classified as failures were investigated with MR at the 1-year follow-up, and 40 patients classified as successes were picked at random for MR imaging; thus MR was performed in 53 patients. The MR images were independently evaluated by two neuroradiologists. The images were rated according to the presence or absence of nerve root displacement at the surgically treated disc interspace. Scar formation was rated according to two different classification systems. RESULTS: Nerve root displacement was observed in 13 patients. No evidence of scar formation was found in 4 patients, a small amount in 11, intermediate in 37 and extensive scar formation in 1 patient. No association between nerve root displacement and the amount of scar tissue was found. CONCLUSION: Postoperative nerve root displacement seems to be an independent clinical entity not associated to postoperative scar tissue.

[Diagnostic imaging in lumbago and sciatica]. / Bildediagnostikk ved lumbago og isjias.

Low back pain and sciatica are among the most common medical problems in Western countries, affecting up to 80% of the population at some time during their lives. Plain radiography is still a sensitive method in degenerative spinal disease and for the identification of spondylolysis and destructions as well as transitional vertebra and other anomalies in the lumbosacral region. In lumbar disk herniation, CT and MR have higher sensitivity than lumbar myelography, and should be used as the primary imaging methods. Myelography is still the method of choice in lumbar spinal stenosis. Myelography should also be considered in patients with poor consistency between CT or MR findings and the clinical presentation. Postoperatively, MR is superior to CT and myelography for distinguishing between scar tissue and recurrent disk herniation.

[Magnetic resonance tomography of biliary and pancreatic ducts]. / Magnetisk resonanstomografi av galle- og pancreasgang.

Magnetic resonance imaging of the biliary and pancreatic ducts, MRCP, is a technique developed over the last few years. Using strongly T2-weighted sequences, images of the biliary and pancreatic ducts similar to ERCP can be obtained within one single inhalation. No contrast media or medication is required. In 23 patients 25 MRCP examinations were retrospectively compared with ERCP or PTC. One patient had normal findings; three had gallbladder stones. Eight out of nine common bile-duct stones were shown. MRCP after papillotomy in one patient showed a common bile-duct stone; ERCP seven days later was normal. MRCP correctly showed obstruction and dilatation of the bileducts in ten patients with tumor and in one patient with chronic pancreatitis. Two of these were erroneously interpreted as caused by stone. 21 of 25 MRCPs were consistent with the final diagnosis. We consider MRCP a promising method which may replace diagnostic ERCP in majority of patients. Stones in the gallbladder and bile-ducts can be diagnosed. The method also shows obstructions and other lesions affecting pancreatobiliary ducts.

[Radiological imaging in lumbago and sciatica]. / Bildediagnostikk ved lumbago og isjias.

Low back pain and sciatica are among the most common medical problems in Western countries, affecting up to 80% of the population at some time during their lives. Plain radiography is still a sensitive method in degenerative spinal disease and for the identification of spondylolysis and destructions as well as transitional vertebra and other anomalies in the lumbosacral region. In lumbar disk herniation, CT and MR have higher sensitivity than lumbar myelography, and should be used as the primary imaging methods. Myelography is still the method of choice in lumbar spinal stenosis. Myelography should also be considered in patients with poor consistency between CT or MR findings and the clinical presentation. Postoperatively, MR is superior to CT and myelography for distinguishing between scar tissue and recurrent disk herniation.

Nerve root signs on postoperative lumbar MR imaging. A prospective cohort study with contrast enhanced MRI in symptomatic and asymptomatic patients one year after microdiscectomy.

The association between postoperative nerve root signs and outcome was investigated in 54 out of one hundred patients operated on by lumbar microdiscectomy in a prospective cohort study with one year follow up. The patients were classified as failures or successes at the 12 month follow up according to a clinical overall score. All the 14 failures were investigated with MRI at the one year follow up, and 40 patients classified as successes were picked at random for MRI. Three patients with signs of recurrent disc herniation on MRI were excluded from the study. The MRI scans were independently read by two neuroradiologists who were ignorant of treatment outcome. No association between nerve root thickening, nerve root enhancement or nerve root displacement and the clinical outcome was found when patients with recurrent disc herniation were excluded.

Cost-effectiveness of percutaneous automated lumbar nucleotomy. Comparison with traditional macro-procedure discectomy.

SUMMARY: This study was conducted in order to evaluate the cost-effectiveness of percutaneous automated lumbar nucleotomy in comparison with traditional macro-procedure discectomy in the treatment of herniated discs. Sixty-eight patients undergoing surgical procedures and 90 treated with nucleotomy were consecutively included. Both cohorts were assessed pre-operatively and at regular intervals for one year or more after treatment by independent observers, using a clinical overall scoring system (COS) with 0 being the best attainable result and 1000 the poorest conceivable status of the patients. There were better clinical results after surgery with 78% successes after one year compared to 62% after nucleotomy. By including subsequent operations and re-operations after failure to respond to the primary treatment, the success rates rose to 79% and 77%, respectively. The cost of surgical treatment was calculated to USD 6.119 per patient and the cost of a nucleotomy procedure was USD 1.252. Owing to an almost five times higher price of surgery than nucleotomy, the latter turned out to be 2.7 to 3.9 times more cost-effective, depending on whether secondary treatment was included or not. Due to the minimal difference in final outcome between the groups, however, the marginal cost per extra success in patients primarily treated with surgery was as high as USD 205.850. The study concludes that nucleotomy, as a mini-invasive procedure with low complication rates and the potential of a quick recovery, is more cost-effective than traditional surgical treatment for lumbar disc herniation.

Pressure measurements in herniated lumbar disks: association with radiologic and clinical data.

This prospective observational study of 85 herniated disks was conducted to investigate the relationship between diskomanometry and radiologic and clinical parameters. The mean injection pressure (P0) was 282 kPa, the residual pressure after 60 s (P60) was 181 kPa, and the loss of pressure (LOP) was 34%. P0 and P60 were moderately intercorrelated (r = 0.51). The following associations were significant: low P0 and P60 in advanced annular degeneration and disruption; low P60 and great LOP in large hernias and narrow disks. P0 and P60 were not associated with the pain response at diskography, magnetic resonance signal intensity, or patient age, sex, weight, body mass index, type of occupation, or duration of symptoms. Diskomanometric data seem to be influenced by the level of annular degeneration and disruption, size of herniation and height of the disk space.

Influence of fibrinolytic factors on scar formation after lumbar discectomy. A magnetic resonance imaging follow-up study with clinical correlation performed 7 years after surgery.

STUDY DESIGN: Prospective cohort study. OBJECTIVES: To assess the amount of scar tissue by viewing magnetic resonance images, and to evaluate the correlation between the amount of scar tissue and clinical outcome, surgical technique, and fibrinolytic factors. SUMMARY OF BACKGROUND DATA: The influence of fibrinolytic factors on magnetic resonance images has not been investigated previously. The relation between clinical outcome and findings on magnetic resonance imaging remains uncertain. METHODS: Magnetic resonance imaging at 0.5 Tesla was performed to produce sagittal and axial spin-echo T1-weighted images before and after contrast enhancement on 78 patients 7 years after traditional lumbar discectomy with partial or full laminectomy. Before surgery all patients had been tested for fibrinolytic factors. RESULTS: The overall clinical success rate of the surgery was 73%. No evidence of scar formation was seen in 19 patients, a small amount was seen in 36 patients, a moderate amount in 17 patients, and a large amount was observed in 6 patients. Ten patients who had undergone surgery at two disc levels and 18 who had been treated with full laminectomy exhibited more scar tissue than those patients who had undergone surgery on a single level (P = 0.033) and those who had undergone a partial laminectomy, respectively (P = 0.017). The amount of scar formation also was associated with a poor outcome (P = 0.017) and with low preoperative values of tissue plasminogen activator antigen (P = 0.003) and tissue plasminogen activity (P = 0.048) in samples collected after venous occlusion. The intensity of contrast enhancement, however, was not influenced by these or any other parameters. CONCLUSION: The amount of scar formation after lumbar discectomy seems to be related to the clinical outcome, the size of the surgical exposure, and some fibrinolytic factors.

[Computer tomography of pathological neck lesions]. / Computertomografi av patologiske tilstander på halsen.

The introduction of high resolution computed tomography (CT) has significantly improved the quality of imaging of neck masses. Incremental dynamic scanning immediately after a quick bolus injection of contrast medium is essential in a majority of patients in order to obtain an optimum of information. This is especially true in the identification, mapping and staging of malignant lesions, which is the main indication for the examination. CT is also very sensitive, and yields detailed information about the location and extent of cystic and other benign lesions. Owing to the low attenuation of fat, the examination is very specific with respect to lipomas. CT has low specificity in the differentiation between benign and malignant lesions, and between cysts and solid tumours of the thyroid gland. In thyroid and parathyroid imaging other modalities such as ultrasound and scintigraphy are often more specific.

Side effects and complications of automated percutaneous lumbar nucleotomy.

We reviewed the records of 243 patients treated at 271 disc levels to determine the incidence of side effects and complications of percutaneous nucleotomy. In our early experience there were 7 technical failures (2.5% of all attempts), of which 6 were at the 5th disc level. The success rate dropped from 67% at 3 months to 60% 1 year after treatment due to recurrences in 16 patients (6.6%). Extruded or sequestered fragments were found in 6 patients (2.4%), and may have been caused by nucleotomy. However, only one was accompanied by aggravation of symptoms. Discitis was seen in 2 patients (0.8%), both treated at two separate disc levels. About half the patients experienced increased low back pain, mean duration 9 days, after treatment, and 3 (1.2%), of whom 2 also had nonorganic disorders, needed admission to hospital because of severe pain. Mild spasm and a sensation of instability were noted by 9.6% and 25% of the patients respectively. Injury to nerves, bowels, vessels or ureters or a dural leak never occurred. The study confirms earlier reports that the rate of serious complications is low.

No association between peridural scar and outcome after lumbar microdiscectomy.

The association between postoperative scar formation on MRI and outcome was investigated in 54 out of one hundred patients operated on with microdiscectomy in a prospective cohort study with a one year follow up. The patients were classified as failures or successes at the 12 months follow up according to a clinical overall score. All the 14 failures were investigated with MRI, and 40 patients classified as successes were picked at random for MRI. Patients with signs of recurrent disc herniation on MRI were excluded. The MRI scans were rated according to the presence or absence of scar formation within the spinal canal and the degree of scar enhancement by two independent neuroradiologists ignorant of treatment outcome. No evidence of scar formation was found in 4 patients, a small amount in 11, intermediate in 38 and extensive scar tissue in 1 patient. Slightly enhancing scar tissue was found in 18 patients, intermediate in 27 patients and strong enhancement in 5 patients. No association between the amount or enhancement of peridural scar formation and clinical outcome was found. Both the total clinical score and the difference between pre- and post-operative clinical score were used in the calculations. Testing the different subsets in the clinical overall score, as well as the patient satisfaction VAS score, did not reveal any association.

Post-Procedure CT Follow-up after Percutaneous Automated Lumbar Nucleotomy.

SUMMARY: In order to evaluate the incidence of soft tissue changes after automated lumbar nucleotomy, a prospective cohort study was performed with follow-up CT within four to six hours after treatment of 97 discs in 88 patients. The CT scans were normal at 47 levels and abnormal at 50. At 11 levels traces of blood were seen along the trajectory, of which nine were located in the subcutaneous fat, one in the extensor and one in the psoas muscle. Small gas collections were observed at 42 levels. Twenty-one of them were located in the extensor and two in the psoas muscle, seven in the subcutaneous fat, two in the epidural space and ten in multiple locations. The abnormal scans were not associated with clinical symptoms different from those with normal scans. The results support previous reports indicating that this procedure is associated with low morbidity and complication rates.

Anatomic variations and pathologic conditions as risk factors of complications in percutaneous lumbar nucleotomy.

SUMMARY: This study was carried out to assess anatomic variations and pathologic changes associated with a potentially increased risk of complications during percutaneous nucleotomy. The MRI and CT examinations of 88 patients were reviewed with regard to the positional relationship between the trajectory to the disc and the bowel and iliac vessels respectively at the L4-L5 and L5-S1 levels. Pathologic conditions involving the anterior part of the annulus were assessed both by MRI and by CT-discography of 97 discs. The shortest distance from the needle course to the bowels was 29 mm. At ten other disc levels this distance was less than 40 mm. The position of the bowels is influenced by the size of the patient, the size and course of the psoas muscles and the amount of retroperitoneal fat. The bowels are at greaten distance from the trajectory at the L5-S1 than at the L4-L5 level. The risk of bowel puncture seems to be minimal. The iliac vessels were positioned behind the midportion of the disc in three patients. There was greater variation and a shorter distance to the trajectory at the L5-S1 than at the L4-L5 level. Anterior disc hernias, and particularly severe annular degeneration involving the anterior part of the annulus are frequently seen. These conditions include a weakening of the annulus and may increase the risk of anterior perforation during nucleotomy.