Acta Radiologica

Purpose: To perform Doppler US in patients with insulin-dependent diabetes mellitus (IDDM) as a predictive method in diabetic nephropathy (DN).

Material and Methods: Twenty-five patients with type I diabetes mellitus underwent renal Doppler US examination. Children were divided into three age groups: group I, 3–7 years; group II, 8–10 years; and group III, 11–18 years. the age-matched control group consisted of 56 healthy children who underwent renal Doppler US only.

Results: the mean values of the resistive index (RI) were, respectively, 0.64 ± 0.03, 0.59 ± 0.04, 0.59± 0.02 in age groups I, II, and III for healthy children and 0.68 ± 0.03, 0.62 ± 0.04, 0.59 ± 0.04 in age groups I, II, and III of the diabetic patients. There were no significant differences between the diabetic and healthy subjects. the mean RI value was not different in the patients with glomerular hyperfiltration compared to patients with normal filtration rate. Additionally, there were no significant differences between the mean RI value in patients with or without microalbuminuria.

Conclusion: Renal Doppler US is not useful for prediction or for early diagnosis of DN.

Purpose: To evaluate the potential usefulness of dynamic MR with echo-planar imaging (EPI) in assessing the renal function in patients with renal allografts.

Material and Methods: Using a T1-weighted sequence, EPI was performed after injection of a Gd-chelate in 17 patients with normally functioning renal allografts. Time-intensity curves were plotted from the signal intensity (SI) measurements of the cortex and the medulla.

Results: the pattern of corticomedullar differentiation (CMD) observed after contrast enhancement was divided into four phases using the T1-EPI. After a rapid decrease in the SI of cortical structures, and a subsequent return to precontrast levels, a gradual fall in the SI of the medulla was observed. the average time between the two periods of signal loss was 60 s.

Conclusion: This study illustrated the potential use of dynamic T1-EPI to demonstrate contrast-induced CMD in renal allografts.

Purpose: To compare conventional MR imaging, echo-planar diffusion-weighted imaging (EP-DWI) and spin-echo diffusion-weighted imaging (SE)-DWI at radiological diagnosis of acute stroke.

Material and Methods: Twenty-seven patients (30–85 years old) were examined. Clinical examination was performed before MR imaging. All MR examinations were assessed by an experienced neuroradiologist blinded to clinical findings.

Results: In EP-DWI, every patient had a lesion corresponding to the clinical findings. EP-DWI was used as the gold standard. In conventional PD + T2 imaging, 23/59 focal lesions were interpreted as acute, which was false in 11 lesions, and 36/59 lesions were considered to be old, 6 were in fact acute. Nine acute lesions were only detected retrospectively and 12 acute lesions were not detected at all on PD + T2. SE-DWI including the apparent diffusion coefficient correlated fairly well with EP-DWI but the procedure was impractical.

Conclusion: EP-DWI is reliable for diagnosis of early ischemic stroke, while SE-DWI performs reasonably well. Conventional PD + T2 imaging is not reliable for diagnosis of early ischemia.

Purpose: the aim of this study was to evaluate any possible effects of brain motion, CSF pulsations and other possible sources of physiological motion in electrocardiographic (ECG) triggered and non-triggered single-shot echo-planar imaging (EPI) measurements of diffusion.

Material and Methods: Three different triggering protocols were evaluated in 6 healthy volunteers: 1) ECG triggering with time delay (TD) 100 ms; 2) ECG triggering with TD 400 ms; and 3) no triggering at all.

Results: the results obtained showed that white matter mean apparent diffusion coefficient (ADC) values were similar for all triggering protocols and that the reproducibility in ADC measurements using diffusion-weighted (DW) EPI was good. the average standard deviation of the ADC values was, however, higher for ADC maps obtained without ECG triggering.

Conclusion: the use of prospective diastolic ECG triggering significantly improves the accuracy of quantitative diffusion measurements but for routine clinical diffusion imaging, where quantitative data is of less importance, the accuracy obtained without ECG triggering can be considered adequate.

Purpose: To examine how an internal carotid artery (ICA) stenosis influences the orbital blood velocity and to determine which velocity parameters are most useful.

Material and Methods: the study group comprised 94 randomly selected patients examined with orbital US; most of the patients had a carotid artery stenosis. There were 58 men and 36 women, ranging in age from 22 to 88 years with a mean age of 63.1 years. the ICA stenosis grade was determined with carotid US. Peak systolic (Vp) and end-diastolic blood velocities, systolic acceleration, mean velocity, pulsatile index (PI) and resistance index (RI) were measured within the central retinal artery (CRA) and the ophthalmic artery (OA), and peak velocity was measured within the central retinal vein (CRV). the area under the ROC curve was used to compare the outcome of diagnostic tests.

Results: Only a severe (>80%) ICA stenosis decreased orbital blood velocity significantly, while milder stenoses did not cause significant flow decrease or side differences. According to ROC curve analysis, the threshold values giving the highest accuracy in detecting a >80% ICA stenosis were Vp <0.08 cm/s for the CRA and Vp <0.14 cm/s for the OA. the sensitivities for detecting a >80% ICA stenosis were 45% for Vp CRA and 60% for Vp OA. Systolic acceleration also decreased in severe stenoses, but RI, PI and velocity in the CRV did not correlate with ICA pathology. Reversal of OA flow was seen in 92% of ICA occlusion and in 47% of severe ICA stenosis.

Conclusion: Orbital Doppler combined with carotid Doppler can be helpful in the diagnosis of the ocular ischaemic syndrome and in the evaluation of whether the symptoms are related to occlusion of the ophthalmic or central retinal vessels or are a consequence of carotid artery stenosis.

Purpose: To determine the diagnostic value of MR imaging for tumors of the floor of the mouth and the effects of the tumors on the sublingual and submandibular glands.

Material and Methods: Thirty-seven patients with proven squamous cell carcinoma of the floor of the mouth underwent MR imaging, including unenhanced T1-weighted, T2-weighted, dynamic, and contrast-enhanced T1-weighted images. the appearance of the tumor and the sublingual and submandibular glands was assessed qualitatively and quantitatively.

Results: All tumors demonstrated replacement of the normal signal intensity in the adjacent sublingual gland. Twenty-one patients (57%) had abnormal signal intensity of the submandibular gland without tumor invasion, presumably secondary to submandibular duct obstruction by the tumor. Unenhanced T1-weighted images provided high contrast between tumor and sublingual gland. Tumors limited within the gland were well detected on unenhanced T1-weighted images. Large tumors extending beyond the gland were well delineated on dynamic images, but no better than on T2-weighted images.

Conclusion: At MR imaging for tumor of the floor of the mouth, one must carefully evaluate the appearance of the sublingual and submandibular glands. Contrast-enhanced studies are unnecessary when the tumor is limited within the sublingual gland on precontrast MR images.

Purpose: NC100150 is a new type of ultra-small iron oxide (USPIO) blood pool agent. the aim of this study was to compare NC100150-enhanced MR angiography (MRA) to time-of-flight (TOF) MRA, phase-contrast (PC) MRA, and digital subtraction angiography (DSA) in experimental stenoses in pigs, and furthermore to determine the optimal dose of the contrast agent.

Material and Methods: An experimental stenosis of the right and left common carotid artery (CCA) was applied surgically in 6 Yorkshire pigs. DSA was performed as the gold standard, followed by 3D-TOE 3D-PC, and NC100150-enhanced MRA.

Results: Eleven stenoses of the CCA were successfully applied. the degree of the stenosis, determined by NC100150-enhanced MRA, did not differ significantly from DSA, whereas TOF and PC MRA underestimated it. the image quality of the NC100150-enhanced MRA was superior to both TOF and PC MRA. the optimal dose of NC100150 was 5–6 mg Fe/kg, since higher doses did not further increase signal-to-noise ratio or contrast-to-noise ratio. There was a linear relationship between blood relaxation rate and contrast dose.

Conclusion: NCl00150-enhanced MRA has the potential for quantification of carotid stenoses and provides an alternative to DSA. the optimal dose of NC100150 was 5–6 mg Fe/kg.

Purpose: To compare iodixanol 270 mg I/ml with iohexol 300 mg I/ml in infrapopliteal arteriography by measuring digital densitometric vessel opacification and by visually assessing angiographic enhancement.

Material and Methods: In a double-blind, dual-balanced, 4-sequence crossover design, 50 claudicant patients received two contrast media injections (10 min interval) in the superficial femoral artery. Digital angiography was performed at 8 frames/s and time-density curves with a circular region of interest over a distal calf artery were generated. A mixed, linear model was used to identify effects influencing the density measurements. Subjective evaluation of the image quality was made independently by two observers.

Results: No statistically significant difference between the contrast media was revealed in the analysis of the densitometric measurements (p = 0.14) nor in the subjective visual evaluation (p = 0.74). However, the mean density at the time of maximum opacification was higher after the first injection than that after the second injection (p = 0.02). There was a tendency towards lower intensity of warmth during injection of iodixanol 270 than during injection of iohexol 300.

Conclusion: In patients with severe occlusive atherosclerotic disease, iodixanol yielded the same image quality as iohexol in infrapopliteal arteriography, in spite of the 30 mg I/ml lower iodine concentration.

Purpose: To evaluate the effect of MR arthrography of the shoulder on diagnostic thinking and therapeutic decisions by orthopedic shoulder surgeons.

Material and Methods: Orthopedic surgeons completed a questionnaire before and after MR arthrography for 73 consecutive patients. the main indications were suspected rotator cuff abnormalities. the clinical diagnosis, the degree of confidence in this diagnosis, and the therapeutic decision were noted before and after MR imaging. Surgical reports were available for 34 patients.

Results: Thirty-four percent of the pre-MR imaging diagnoses were withdrawn after MR imaging, and new diagnoses were made after MR imaging in 13% of the case & Confidence in the diagnosis increased significantly after MR imaging for supraspinatus and infraspinatus lesions (p < 0.05). Changes of therapeutic decision after MR imaging were noted in 36 of the 73 patients (49%). In 23 patients, more invasive therapeutic procedures were initiated after MR imaging, and a more conservative treatment was implemented for 13 patients. Agreement of MR diagnoses with surgery was 94% for supraspinatus tears, 87% for infraspinatus tears, 77% for subscapularis tears, and 81% for biceps tendon lesions. Agreement of clinical diagnoses with surgery was 56%, 83%, 50%, and 64%, respectively.

Conclusion: MR arthrography of the shoulder has a major effect on diagnostic thinking and therapeutic decisions by orthopedic shoulder surgeons.

Purpose: To investigate the value of MR imaging using a low-field imaging unit (0.2 T) for the evaluation of ligaments and tendons of the ankle.

Material and Methods: Twelve ankle specimens were studied using low-field MR imaging (0.2 T). the Achilles tendon, the tibialis posterior tendon, and the lateral collateral ligaments were evaluated for the presence of degenerative changes and partial and complete tears. Visibility and overall image quality were analyzed by qualitative evaluation.

Results: Low-field MR images of the 24 tendons were interpreted as normal in 11 cases, showing degenerative changes in 9 cases and a partial tear in 1 case. Visualization was regarded as not sufficient for a diagnosis in 3 cases. of the 36 ligaments, 14 were regarded as normal while degenerative changes were seen in 5 cases and a tear in 2 cases. In 13 cases, no diagnosis could be established, and in 2 cases only a probable diagnosis was established. the best overall quality was obtained with the use of T1 spin-echo (680/20/4) and T2 multi-echo (3000/40/1) images.

Conclusion: Optimized protocols for examination of the ankle using low-field MR imaging may allow evaluation of the Achilles and tibialis posterior tendons, but these protocols may not be as useful for diagnosing ligamentous changes.

Objective: the uptake of bone-seeking radiopharmaceuticals depends on the blood flow, which is influenced by the sympathetic nervous system. Our aim was to study the effect of sympathomimetic drugs on the distribution of bone-seeking agents.

Material and Methods: Various sympathomimetic and β-blocking drugs were injected in mice at different times in relation to the administration of ^99mTc-HDP Three hours after this, venous blood and various organs were removed and their activities were related to the administered activity. A kinetic study of the whole-body activity retention after administration of terbutaline was also made.

Results: the biodistribution of ^99mTc-HDP was similar after the administration of sympathomimetics and of β-antagonists. All drugs gave rise to an increased soft tissue activity and a decreased bone activity, corresponding to a lowered quality of the potential bone scan. Terbutaline gave rise to an increased excretion of ^99mTc-HDP. the mechanisms behind the findings cannot be entirely explained.

Conclusion: Drug interference with the sympathetic nervous system causes undesirable effects on the biodistribution of ^99mTc-HDP in the mouse. Studies in humans are necessary to evaluate whether clinical treatment with sympathotropic drugs affects the bone scintigram.

Purpose: To evaluate MR imaging for tissue volume measurements.

Material and Methods: Imaging was done with a spoiled gradient echo technique using the human lower leg as a simple model and CT as the reference technique. Areas of adipose tissue, muscle plus skin and bone tissue were evaluated in 5 volunteers using signal intervals (MR) and attenuation intervals (CT) defined by histograms. Volumes were determined from 7 images (MR-7, CT-7), from 70 contiguous images (MR-70), and also from a commercially-available 3D program based on a seeding technique applied according to the operators' judgment (MR-op).

Results: the sum of bone tissue, muscle plus skin and adipose tissue were similar for CT and MR. Compared to CT-7, MR-7 and MR-70 overestimated adipose tissue (0–8%) and muscle plus skin (11–15%), while bone tissue was underestimated (61–78%). Determinations based on the contiguous images or the 7 images were similar (standard error 2–5%). MR-op resulted in pronounced underestimation of muscle plus skin and bone tissue and a minor underestimation of adipose tissue.

Conclusion: Valid determinations of adipose tissue volume are possible with MR but further technical development is required for other tissue volumes. the technique applied according to the operators' judgement, as used for 3D surface rendition, is unreliable for tissue volume determinations.

Purpose: To compare a 3D echo planar imaging (EPI) sequence with four other T1-weighted sequences for imaging of the liver at 1 T.

Material and Methods: Twenty volunteers were included in our imaging protocol. Spin-echo (SE), turbo SE (TSE), turbo field echo (TFE) in 2D and 3D acquisition mode, fast field echo (T1-FFE) and 3D EPI sequences were applied. Signal-to-noise (S/N) ratio of the liver, contrast-to-noise (C/N) ratio and relative contrast (ReCon) between the liver and the spleen, scanning time per slice and artifact levels were evaluated.

Results: 3D EPI provided a statistically equivalent S/N ratio of the liver with SE and T1-FFE sequences (p > 0.05), while it provided a statistically higher S/N ratio of the liver compared to TFE sequences (p < 0.05). The TSE technique provided a statistically higher S/N ratio of the liver compared to 3D EPI (p < 0.05). With regard to the liver-spleen C/N ratio, 3D EPI provided statistically equivalent results compared to all sequences except T1-FFE, where 3D EPI was superior. With regard to liver-spleen ReCon, 3D EPI was statistically equivalent to SE, TSE and T1-FFE, while it provided significantly higher liver-spleen ReCon than 3D TFE and significantly lower than 2D TFE.

Conclusion: 3D EPI provided sufficient ReCon and C/N ratio and produced motion-free images in one breath-hold period. Further clinical studies are required to estimate the sensitivity, specificity and accuracy of the sequence.

Alveolar echinococcosis is a rare parasitic disease caused by Echinococcus multilocularis and most commonly involves the liver. Early diagnosis and precise evaluation of the localisation and the extent of the lesions are essential for treatment. In this report, we present US and CT findings in a patient with hepatic alveolar echinococcosis.

The case of a 4-year-old patient with a diaphragmatic haemangioma is reported. There were no symptoms and the only clinical finding was prominent subcutaneous vessels on the abdominal wall. the lesion was revealed by imaging and was excised. the findings and the differential diagnosis are discussed.

Purpose: The aim of this study was to obtain more accurate data on the electron density of the lungs in healthy subjects and to determine the factors that influence this value.

Material and Methods: Single kVp quantitative CT was applied in 130 normal adults (61 men and 69 women) to study the electron density of the lung.

Results: The electron density of the lung in men was lower than that in women. In contrast, the area designated as lung in men was larger than that in women. The mean electron density decreased with increasing age in men, but not in women. The following parameters were not found to influence lung electron density: body mass, body height, smoking habits, and right or left lung. The electron density of the lung medial to the thoracic wall and close to the breast was lower than the density in the entire lung parenchyma.

Conclusion: Quantitative CT provided the means to study noninvasively the electron density of the lung and the factors that influence this value.

Monte Carlo Calculations in Nuclear Medicine. Applications in Diagnostic Imaging. Edited by M. Ljungberg et al. Medical Science Series, IOP Publishing Ltd 1998. ISBN 0 7503 0479 0. Reviewed by Bo Jung.

Encyclopaedia of Medical Imaging. I. Physics, Techniques and Procedures. Edited by H. Pettersson et al. Nicer, Oslo. ISBN 82 91942 013. Reviewed by Peter Aspelin.

Posttherapeutic Neurodiagnostic Imaging. Edited by J. R. Jinkins. Lippincott-Raven Publ., Philadelphia 1997. ISBN 0 397 58406 7. Price: Hardbound USD 143.75. Reviewed by Raili Raininko.

Ultrasound Review of the Abdomen, Male Pelvis and Small Parts. By J. Hickey & E Goldberg. Lippincott 1998. ISBN 0 397 51691 6. Price: Softbound USD 54.50. Reviewed by Terry Bärlin.