Intracoronary delivery of Gd-DTPA and Gadophrin-2 for determination of myocardial viability with MR imaging.

The aim of this study was to compare intracoronary (i.c.) administration of Gadophrin-2, a necrosis-avid contrast agent (NACA), and nonspecific agent Gd-DTPA for determination of myocardial viability (MV) in acute myocardial infarction (AMI) with MRI. Reperfused AMI was induced in 12 dogs by transcatheter balloon occlusion of coronary artery. In 6 dogs each, Gd-DTPA at 0.1 mmol/kg or Gadophrin-2 at 0.005 mmol/kg was administered into coronary artery by fast bolus (n = 3) or slow infusion (n = 3). Serial ECG-triggered cardiac MRI of T1-weighted segmented turbo fast low-angle shot (FLASH) sequence was conducted and compared with triphenyltetrazolium chloride (TTC) histochemical staining. The contrast ratio and infarct size were quantified and analysed statistically. No cardiovascular side effects were found with local delivery of both agents. After i.c. administration, Gadophrin-2 induced a strong (CR > or = 1.78) and persistent (> or = 10 h) contrast enhancement of infarcted region. The infarct size defined with Gadophrin-2 was almost identical to that with TTC staining throughout the postcontrast period. With a dose 20 times higher, Gd-DTPA also strongly enhanced infarct-to-normal contrast; however, the enhancement diminished with time, i.e. from early strong to later faint enhancement and eventual loss of contrast. The delineated infarct size was also unstable, i.e. from early overestimation to later underestimation and eventual disappearance of the enhanced infarct. In combination with PTCA procedure, i.c. administration of MRI contrast agents may prove useful for post-procedure verification of diagnosis. The NACA-enhanced MRI may serve as an in vivo surrogate of postmortem histochemical staining for determination of MV. Although applicable in clinical setting, cardiac MRI with nonspecific Gd-DTPA is less reliable and should be performed within less than 1 h after contrast.

A novel "cooled-wet" electrode for radiofrequency ablation.

In the light of growing demands for improved applicability of radiofrequency ablation (RFA), recently we have developed a novel "cooled-wet" electrode by taking the advantages of both internally cooled and saline-enhanced electrodes. The efficacy of the electrode was evaluated in both ex vivo and in vivo liver RFA under both low and high power output levels. The ablation volume created with the "cooled-wet" electrode appeared to be much larger than that reported up to now with the use of other monopolar electrodes. The mechanisms on how this device optimizes the RF energy delivery are also discussed.

Three-dimensional imaging of acetabular dysplasia: diagnostic value and impact on surgical type classification.

OBJECTIVE: To investigate the diagnostic value and the impact on surgical type classification of three-dimensional (3D) images for pre-surgical evaluation of dysplastic hips. MATERIALS AND METHODS: Three children with a different surgical type of hip dysplasia were investigated with helical computed tomography. For each patient, two-dimensional (2D) images, 3D, and a stereolithographic model of the dysplastic hip were generated. In two separate sessions, 40 medical observers independently analyzed the 2D images (session 1), the 2D and 3D images (session 2), and tried to identify the corresponding stereolithographic hip model. The influence of both image presentation (2D versus 3D images) and observer (degree of experience, radiologist versus orthopedic surgeon) were statistically analyzed. The SL model choice reflected the impact on surgical type classification. RESULTS: Image presentation was a significant factor whereas the individual observer was not. Three-dimensional images scored significantly better than 2D images (P=0.0003). Three-dimensional imaging increased the correct surgical type classification by 35%. CONCLUSION: Three-dimensional images significantly improve the pre-surgical diagnostic assessment and surgical type classification of dysplastic hips.

Treatment of VX2 liver tumor in rabbits with "wet" electrode mediated radio-frequency ablation.

Radio-frequency ablation (RFA) has been considered as an alternative therapy for liver tumors. A "wet" electrode with interstitial infusion of hypertonic saline was tested for the RFA of liver tumor in rabbits. Seventy-eight liver tumors ( 1.5 to 3.0 cm) were induced in 41 rabbits by VX2 carcinoma implantation. Fifty-one tumors in 27 rabbits were treated with RFA. Under laparotomy, the RF energy was delivered while 5 % saline was infused through the electrode into the tumor at 1 ml/min. Six rabbits with 12 tumors were treated with only intratumoral 5 % saline infusion without RFA. Another 8 rabbits with 15 tumors received sham operation as untreated controls. The efficacy of the therapy was evaluated with survival rate, MRI, microangiography, and histopathology. In the RFA group, 6 rabbits survived longer than 6 months (absolute eradication rate 22.2 %); 12 rabbits were found free of viable tumor at the moment when they were sacrificed (relative eradication rate 44.4 %); 9 rabbits showed local tumor relapse and/or lung metastasis 2-10 weeks after ablation (recurrent rate 33.3 %). In control groups of saline infusion and sham operation, all 14 rabbits died within 3 months (mortality rate 100 %). Three-month survival rates between RFA group and control groups were significantly different (p < 0.05). Findings of MRI, microangiography, and histology supported these outcomes. Radical treatment of liver malignancy in rabbits is possible with the present modified RFA technique. Its clinical usefulness has to be further proven.

Value of computed tomography as outcome predictor of supraglottic squamous cell carcinoma treated by definitive radiation therapy.

PURPOSE: To investigate the value of several CT-derived tumor parameters as predictors of local outcome of supraglottic squamous cell carcinoma treated by definitive radiation therapy. METHODS AND MATERIALS: The pretreatment CT studies of 103 patients with supraglottic squamous cell carcinoma were reviewed for tumoral involvement of specific laryngeal anatomic subsites and extralaryngeal tumor spread. After redigitizing the films, tumor volume was calculated with the summation-of-areas technique. Mean follow-up time was 3.4 years. Actuarial statistical analysis of local and locoregional outcome was done for each of the covariates; multivariate analysis was performed using Cox's proportional hazards model. RESULTS: In the actuarial analysis CT-determined primary tumor volume was significantly correlated with local recurrence rate (p < 0.001). Degree of involvement of the paraglottic space at the level of the true vocal cord (p < 0.05) and subglottic extension (p < 0.001) were also significantly correlated with local recurrence rate. In the multivariate analysis, only degree of involvement of the preepiglottic space (p < 0.01) and subglottic extension (p < 0.01) were found to be independent predictors of local recurrence. Total tumor volume was the strongest independent predictor of locoregional failure (p < 0.01). CONCLUSIONS: CT-determined tumor parameters are strong predictors of local and locoregional outcome of supraglottic carcinoma treated by definitive irradiation.

Predicting the local outcome of glottic squamous cell carcinoma after definitive radiation therapy: value of computed tomography-determined tumour parameters.

BACKGROUND AND PURPOSE: The T-classification has shortcomings in the prediction of local outcome of glottic squamous cell carcinoma (SCC) treated by definitive radiation therapy. In this regard, the value of several CT-derived tumour parameters as predictors of local outcome was investigated. MATERIALS AND METHODS: The pretreatment CT studies of 119 patients with glottic SCC (T1, n=61; T2, n=40; T3, n=14; T4, n=4) treated with curative intent by radiation therapy were reviewed for tumoral involvement of specific laryngeal anatomic subsites (including laryngeal cartilages). Tumour volume was calculated with the summation-of-areas technique. Actuarial (life-table) statistical analysis was done for each of the covariates; multivariate analysis was performed using the Cox proportional hazards model. RESULTS: In the actuarial analysis tumour volume was significantly correlated with local recurrence rate (P=0.0062). Involvement of the cricoid cartilage (P=0.0052), anterior commissure (P=0.0203), subglottis (P=0.0481) and preepiglottic space (P=0.0134) and degree of involvement of the true vocal cord (P=0.0441) and paraglottic space at the level of the true vocal cord (P=0.0002) were also significantly correlated with local recurrence rate. In the multivariate analysis, only degree of involvement of the paraglottic space (at the level of the true vocal cord) (P=0.0001) and preepiglottic space (P=0.02) were found to be independent predictors of local recurrence. The T-category was significantly correlated with local outcome in the actuarial analysis (P=0.0001), but not in the multivariate analysis (P=0.5915). CONCLUSIONS: Several CT-derived parameters are powerful predictors of local outcome in glottic cancer treated with radiation therapy; some of these parameters are stronger linked to the local control rate than the T-classification.

Solitary true cyst of the pancreas.

We report a case of a woman diagnosed with a solitary true cyst of the pancreas. CT and especially MRI guided us in the diagnosis of this benign lesion. The cyst has been surgically removed because of secondary bile-duct obstruction causing painless jaundice. Clinical history, laboratory, imaging, and histological findings are reported.

Langerhans cell histiocytosis of the clavicle: a case report.

A case of Langerhans cell histiocytosis in a 47-year-old male presenting as an aggressive appearing lesion of the clavicle is reported. It illustrates the difficulties of the radiological diagnosis of a solitary bone lesion.

Expiratory CT in cigarette smokers: correlation between areas of decreased lung attenuation, pulmonary function tests and smoking history.

The aim of this study was to determine the correlation between cigarette-smoke-related bronchial disease and air trapping as assessed by expiratory high-resolution CT (HRCT) scans. Thirty healthy subjects (11 non-smokers, 7 ex-smokers for > 2 years, 12 current smokers; age range 35-55 years) with a smoking history between 0 and 28.5 pack-years underwent pulmonary function tests (PFT) and HRCT in inspiration and expiration in supine and prone position. The extent of air trapping was scored in ventral and dorsal aspects of the upper, middle and lower lung portions. In 24 subjects (7 non-smokers, 7 ex-smokers, 10 current smokers) areas of focal air trapping were found, and were present significantly more often in dependent lung portions (p < 0.05) compared with non-dependent portions. No significant differences were found between apical and basal lung zones. Scores of focal air trapping were not significantly different between smokers and ex-smokers, but were significantly lower (p < 0.05) in non-smokers and showed a significant (p < 0.0005) correlation with pack-years. The degree of air trapping was also associated with several lung function tests, especially RV, DLCO, FRC, FEV1 and FEV1/VC. Air trapping is seen in smokers with normal PFT and correlates with the severity of the smoking history, independently of current smoking status.

Acute obstruction of the renal collecting system: the intrarenal resistive index is a useful yet time-dependent parameter for diagnosis.

The aim of this study was to determine whether the intrarenal resistive index (RI) can be used for the diagnosis of acute obstruction in patients with renal colic and to determine whether the index is time-related. Seventy patients referred to the Emergency Department with acute renal colic and without known associated renal disease underwent duplex Doppler ultrasonography to determine the intrarenal RI at the symptomatic and asymptomatic side. The age range of the patients was 18-72 years. An RI greater than 0.68 and/or an interrenal difference in RI greater than 0.06 and/or an increase in RI of more than 11% compared with the normal side proved reliable cut-off values to diagnose acute renal obstruction. In addition, time dependency of the increase in RI was noted. No significant differences were observed within the first 6 h after the onset of symptoms. From 6 to 48 h, however, the mean RI in the affected kidney (0.70 +/- 0.06; mean +/- SD) was significantly different from that in the normal kidney (0.59 +/- 0.04) (P < 0.001). In the same period the mean difference in RI was 0.08-0.13 (P < 0.001). After 48 h the sensitivity of RI dropped substantially. It is concluded that renal duplex Doppler ultrasonography is useful for diagnosing acute renal obstruction between 6 and 48 h after the onset of symptoms.

Cranial CT revisited: do we really need contrast enhancement?

The aim of this study was to define guidelines for intravenous contrast administration in cranial CT, as currently there are no recent guidelines based on a large series of patients. In 1900 consecutive patients (1480 adults and 420 children) pre- and post-contrast scan was analysed in order to assess the contribution of contrast enhancement to the diagnosis. The findings were grouped according to whether abnormalities were seen on the pre- and/or post-contrast scan, or whether no abnormalities were seen at all. Sensitivity, specificity, positive predictive value, negative predictive value and accuracy of a pre-contrast scan were used to determine validity. Intravenous contrast enhancement only contributes to the diagnosis if a suspicious abnormality is seen on the unenhanced scan or in the appropriate clinical setting (33.6%). In the remaining patients (65.6%) there is no diagnostic contribution, except for a small number of abnormalities (0.8%). These are often anatomical variants and have no therapeutic impact. The number of contrast-enhanced cranial CT examinations can significantly be reduced by using four general guidelines for contrast administration resulting in considerable cost savings without affecting the quality of service to the patient. These guidelines are defined by the clinical findings/presentation or by the findings on the unenhanced scan. The number of contrast-related complications will be reduced, which may have medicolegal implications. These guidelines can be applied in any radiology department.

Computed tomography of laryngeal carcinoma: technique, imaging findings and implications for radiation therapy.

Optimal radiological visualisation of laryngeal carcinoma demands for a tailored imaging technique. The technique for computed tomography of the larynx is reviewed, and imaging findings in laryngeal carcinoma are described. The application of CT-findings for selection of patients into the favourable group for radiation therapy is discussed. The use of CT in the follow-up of irradiated laryngeal carcinoma is reviewed.

Langerhans cell histiocytosis of the cervical spine: case report of an unusual location.

An unusual location for Langerhans cell histiocytosis of the cervical spine is presented. The osteolytic lesion, instead of being located in the vertebral body, was visualised in the left lateral mass of the fifth cervical vertebra, extending into the vertebral body and through the interapophyseal joint into the lateral mass of the fourth cervical vertebra.

Fast FLAIR MRI in childhood white-matter abnormalities.

We compared a fast fluid-attenuated inversion recovery (FLAIR) pulse sequence with a dual-echo short tau fast inversion-recovery (DESTTIR) sequence in 20 children with white matter abnormalities. Although the overall image quality of DESTTIR images was better, the lesion-to-background contrast was significantly higher with the fast FLAIR pulse sequence and lesion detection was more accurate.

Transitional cell carcinoma in a renal allograft.

A large urothelial tumor was detected by ultrasonography in the dilated collecting system of a well-functioning renal allograft 15 years after transplantation. The tumor was confirmed at computed tomography. Nephrectomy showed a transitional cell carcinoma. The occurrence of malignant tumors in renal allografts is a well known but rare complication.

Chondroblastoma of the patella with a secondary aneurysmal bone cyst.

A case of chondroblastoma of the patella combined with an aneurysmal bone cyst is presented. Chondroblastoma of the patella is an uncommon, benign neoplasm. On the other hand, secondary aneurysmal bone cyst is frequently associated with giant cell tumour of chondroblastoma.

T2-weighted MR imaging of the uterus: comparison of optimized fast spin-echo and HASTE sequences with conventional fast spin-echo sequences.

OBJECTIVE: Our objective was to compare the value of a half-Fourier acquisition single-shot turbo spin-echo (HASTE) sequence with optimized fast spin-echo and conventional fast spin-echo techniques in evaluation of the uterus. SUBJECTS AND METHODS: Optimized fast spin-echo imaging was compared with fast spin-echo and HASTE imaging, for both image quality and ability to assess the zonal anatomy of the uterus, in 40 volunteers. In optimized fast spin-echo imaging, the imaging time was reduced using partial-Fourier reconstruction, reducing the echo spacing, and increasing the echo train length. RESULTS: HASTE imaging offered the least motion artifact of all techniques. On optimized fast spin-echo imaging, motion artifacts were moderate to severe in 10% of patients. On fast spin-echo imaging, motion artifacts were moderate to severe in 40% of patients. Optimized fast spin-echo imaging was superior to the other two techniques in terms of anatomic sharpness and overall image quality. CONCLUSION: Although HASTE imaging offers the unique feature of providing images free of motion artifacts, optimized fast spin-echo imaging appears to be the preferred technique for T2-weighted imaging of the uterus.

Normal Vaterian sphincter complex: evaluation of morphology and contractility with dynamic single-shot MR cholangiopancreatography.

OBJECTIVE: The objective of this study was to assess the usefulness of dynamic single-shot MR cholangiopancreatography in the evaluation of the morphology and contractility of the normal Vaterian sphincter complex and to assess whether i.v. injection of glucagon can improve visualization. SUBJECTS AND METHODS: Sixty patients without signs of Vaterian sphincter complex dysfunction were studied. A fast single-shot MR imaging sequence was used to obtain 20 consecutive images of the Vaterian sphincter complex during successive episodes of breathholding. In patients of group A (n = 30), 10 images were obtained before and 10 after i.v. administration of a sphincter-relaxing agent (glucagon). In the patients of group B (n = 30), no glucagon was administered. The degree of visualization of the Vaterian sphincter complex was assessed. RESULTS: Overall, the morphology and contractility of the Vaterian sphincter complex was adequately assessed in 57 patients (95%). However, the number of repetitions required to obtain this result varied greatly (mean, seven; range, two to 18). Glucagon had no apparent effect on the visibility of the most distal portion of the common bile duct. CONCLUSION: Nonvisualization of the most distal portion of the common bile duct on MR cholangiopancreatography studies is a normal variant that can simulate disease. Obtaining serial breath-hold images using a single-shot technique is helpful to avoid diagnostic errors.

MR of cerebellar cortical dysplasia.

MR imaging findings are described in four patients with cerebellar cortical dysplasia. Typically, cerebellar disorganized folia were seen as an irregular bumpy gray-white matter interface. In addition, cystlike cortical abnormalities were observed in two patients and associated supratentorial developmental abnormalities were seen in three patients. To our knowledge, cerebellar cortical dysplasia without supratentorial abnormalities, as seen in one patient, has not been reported before. We suggest that cerebellar cortical dysplasia represents a spectrum of abnormalities ranging from mild to extensive in severity.