Endorectal diffusion-weighted imaging in prostate cancer to differentiate malignant and benign peripheral zone tissue

PURPOSE: To determine if the apparent diffusion coefficient (ADC) can discriminate benign from malignant peripheral zone (PZ) tissue in patients with biopsy-proven prostate cancer that have undergone endorectal diffusion-weighted imaging (DWI) of the prostate. MATERIALS AND METHODS: Ten patients with prostate cancer underwent endorectal magnetic resonance imaging (MRI) in addition to DWI. A two-dimensional grid was placed over the axial images, and each voxel was graded by a 4-point rating scale to discriminate nonmalignant from malignant PZ tissue based on MR images alone. ADC was then determined for each voxel and plotted for nonmalignant and malignant voxels for the entire patient set. Second, with the radiologist aware of biopsy locations, any previously assigned voxel grade that was inconsistent with biopsy data was regrouped and ADCs were replotted. RESULTS: For the entire patient set, without and with knowledge of the biopsy data, the mean ADCs for nonmalignant and malignant tissue were 1.61 +/- 0.27 and 1.34 +/- 0.38 x 10(-3) mm2/second (P = 0.002) and 1.61 +/- 0.26 and 1.27 +/- 0.37 x 10(-3) mm2/second (P = 0.0005), respectively. CONCLUSION: DWI of the prostate is possible with an endorectal coil. The mean ADC for malignant PZ tissue is less than nonmalignant tissue, although there is overlap in individual values.     

Stroke patients' evolving symptoms assessed by tractography

PURPOSE: To test the hypothesis that an interval evolution in the location of the depicted sensorimotor tract relative to the infarct (the "tract-infarct relationship") may be related to stroke victims' symptom progression. MATERIALS AND METHODS: Patients (N = 7) who underwent multiple diffusion-tensor imaging (DTI) studies during symptomatic progression were included in this study. DTI was performed using a single-shot echo-planar imaging (EPI) technique with a motion-probing gradient in six orientations, a b-value of 800 seconds/mm2, and six image averages. The total scan time was four minutes and 24 seconds. Fiber-tracking of the sensorimotor pathways was performed, and the locations of these tracts were retrospectively assessed in relation to the evolution of the symptoms. RESULTS: Five of the seven patients showed an interval enlargement of the infarct on diffusion-weighted (DW) images. In two of these cases the lesion enlarged to involve the sensorimotor tracts, while in three cases the lesion enlarged only so far to come into close proximity to the sensorimotor tract. In the remaining two cases there was no interval enlargement of the infarct, and therefore the tract-infarct relationship could not account for the evolution of the symptoms in these cases. CONCLUSION: A tract-infarct relationship can be observed with the use of a fiber-tracking technique, and the results may improve our understanding of the symptom progression seen in stroke victims.     

Factors affecting increasing radiation dose for mammography in North Carolina from 1997 through 2001: an analysis of Food and Drug Administration annual surveys

RATIONALE AND OBJECTIVES: To determine which factors affected the increase in average glandular dose recorded at the annual US Food and Drug Administration Mammography Quality Standards Act inspections of mammography equipment in North Carolina from 1997 to 2001. MATERIALS AND METHODS: Average glandular dose, HVL, kVp, ambient light, luminance, equipment age, processing speed, and system speed for every mammography unit at all facilities in the state were collected by state inspectors. A mixed-effect model was used to assess the average changes of glandular dose over time and to identify the factors associated with these changes. RESULTS: There was a statistically significant increase in the average glandular dose in North Carolina in 1999, 2000, and 2001 when compared with the baseline year of 1997. Factors that were statistically significantly linked to this effect were changes in kVp, processing speed, and system speed. CONCLUSION: Average glandular dose for mammography has recently increased in North Carolina. This change is likely caused by changes in screen-film products and processing techniques.     

Randomized prospective study comparing high-dose-rate intraluminal brachytherapy (HDRILBT) alone with HDRILBT and external beam radiotherapy in the palliation of advanced esophageal cancer

PURPOSE: HDRILBT is one of the best methods of palliation for advanced esophageal cancer (AEC) by improving dysphagia-free survival (DFS) and overall survival (OS). This study examines if the addition of EBRT would further improve the outcome by improving DFS in AEC. METHODS AND MATERIALS: Patients with inoperable AEC were entered into a randomized prospective study. HDRILBT of 16 Gy/2 fractions/3 days was given initially to all patients. Following treatment, patients were randomized to receive no further treatment (Group A) or additional EBRT of 30 Gy/10 fractions/2 weeks (Group B) and were followed for 1 year. Statistical analysis of the data was done using the SAS statistical software package (SAS Institute, Cary, NC). Prognostic variables were analyzed using the chi(2) and log-rank tests and survival curves were drawn using the Kaplan-Meier method. Multivariate survival analysis was done using the Cox proportional hazards model. RESULTS: Sixty patients were entered into the study. Patient and tumor characteristics were comparable among the groups. Of 30 patients in Group B, 2 refused additional EBRT (no dysphagia). At 6 months, >50% had DFS in both groups and this was comparable. There was no difference statistically (p >0.05) in the DFS and OS between the two groups at the end of 12 months. Median survival for Group A was 7.23 months and 7.5 months for Group B. Additional EBRT did not improve DFS or OS. Eleven patients developed strictures related to radiotherapy and were dilated successfully (Group A, 7; Group B, 4; p >0.05). Four patients had progressive luminal disease which progressed to fistula (Group A, 3; Group B, 1; p >0.05). There was no effect of any patient or treatment parameter on DFS. Presenting weight and ECOG score had an impact on OS. CONCLUSIONS: From the preliminary analysis, additional EBRT to HDRILBT does not improve DFS or outcomes in inoperable AEC.     

Preliminary results of transarterial rhenium-188 HDD lipiodol in the treatment of inoperable primary hepatocellular carcinoma

A multicentre study was sponsored by the International Atomic Energy Agency (Vienna) to assess the safety and efficacy of trans-arterial rhenium-188 HDD conjugated lipiodol (radioconjugate) in the treatment of patients with inoperable hepatocellular carcinoma (HCC). The radioconjugate was prepared by using an HDD (4-hexadecyl 1-2,9,9-tetramethyl-4,7-diaza-1,10-decanethiol) kit developed in Korea, and lipiodol. Over a period of 18 months, 70 patients received at least one treatment of radioconjugate. Some patients were re-treated if there was no evidence of disease progression. The level of radioconjugate administered was based on radiation-absorbed dose to critical normal organs, calculated following a scout dose of radioconjugate. The organs at greatest risk for radiation toxicity are the normal liver, the lung and the bone marrow. An Excel spreadsheet was used to determine maximum tolerated activity (MTA), defined as the amount of radioactivity calculated to deliver no more than 12 Gy to lungs, or 30 Gy to liver, or 1.5 Gy to bone marrow. These doses have been found to be safe in multiple trials using external beam therapy, but this has not been confirmed for systemically administered radiopharmaceuticals. Patients were followed for at least 12 weeks after therapy, until recovery from all toxicity. The clinical parameters evaluated included toxicity, response as determined by contrast-enhanced computed tomography, palliation of symptoms, overall survival, performance status (Karnofsky) and hepatic function (Childs classification). Liver function tests, serum -fetoprotein (AFP) levels and complete blood counts were done at each follow-up visit. In the majority of patients, the scout dose studies indicated the radiation absorbed dose to normal liver to be the limiting factor to the treatment dose, while in a few patients dose to lung was the limiting factor. Radiation dose to bone marrow was negligible and was thus not a factor for the MTA calculations. Side-effects were minimal and usually presented as loss of appetite, right hypochondrial discomfort and low-grade fever, even at high levels of administered radioactivity. The symptoms resolved with simple supportive therapy within 3 days of onset. Liver function tests at 24 and 72 h showed no significant changes and complete blood counts at 1 week, 4 weeks and 12 weeks showed no changes (no bone marrow suppression). Sixteen patients were treated in the dose escalation phase of the study, when the activities administered started at 1.8 GBq (50 mCi) and rose to 7.7 GBq (206 mCi). In the efficacy phase of the study a further 54 patients were treated. Both groups of patients are included in this paper. The treatment activity of ¹⁸⁸Re-lipiodol administered transarterially ranged from 1.8 to 9.8 GBq (50–265 mCi), with a mean activity of 4.6 GBq (124 mCi). Survival at 3 months was 90%, and at 6 months, 60%; 19% survived for 1 year. Mean survival after treatment in the total treated group of 70 patients was 9.5 months, with a range of 1–18 months. The results of this multicentre study show that ¹⁸⁸Re-lipiodol is a safe and cost-effective method to treat primary HCC via the transarterial route. In terms of efficacy, it is potentially a new therapeutic approach for further evaluation by treatment of larger numbers of patients.     

The feasibility of low-dose CT for pulmonary metastasis in patients with primary gynecologic malignancy

PURPOSE: To assess the feasibility of low-dose CT (LDCT) in the detection of pulmonary metastases in patients with primary gynecologic malignancies and also to compare the performance of chest digital radiography (DR) and LDCT for their delectability of pulmonary metastases, with use of standard-dose CT (SDCT) as the reference standard. MATERIALS AND METHODS: Thirty female patients with primary gynecologic malignancies (age range, 20-76 years; mean age, 50 years) underwent DR, noncontrast LDCT and contrast-enhanced SDCT, which were performed within an interval of 2 weeks. We used lung nodule, mediastinal lymphadenopathy (>10 mm in the short axis) and pleural changes (including effusion, irregular thickening, or nodularity) as the cardinal imaging findings of lung metastases. A five-point scoring system was designed to indicate the probability of lung metastasis from primary gynecologic malignancies. The five-point scores of DR, LDCT, and SDCT were analyzed by receiver operating characteristic (ROC) curve. RESULTS: SDCT probability scores of +2 and -2 were set to indicate true positive and true negative for pulmonary nodule, mediastinal lymphadenopathy, and pleural effusion, respectively. All the areas under the ROC curve of LDCT appeared to be larger than those of DR[pulmonary nodule: 0.96 [95% confidence interval (CI): 0.92-1.01] vs. 0.74 [95% CI: 0.57-0.91], 0.82 [95% CI: 0.70-0.95] vs. 0.61 [95% CI: 0.50-0.77]; mediastinal lymphadenopathy: 0.98 [95% CI: 0.93-1.03] vs. 0.90 [95% CI: 0.79-1.01], 0.94 [95% CI: 0.82-1.06] vs. 0.66 [95% CI: 0.44-0.88]; and pleural effusion: 0.98 [95% CI: 0.93-1.03] vs. 0.56 [95% CI: 0.29-0.82], 0.90 [95% CI: 0.74-1.05] vs. 0.46 [95% CI: 0.23-0.68]]. CONCLUSION: The performance of LDCT were comparable to those of SDCT and superior to those of DR for detection of pulmonary nodule, mediastinal lymphadenopathy, and pleural effusion. By using LDCT, there was no need of intravenous contrast injection and less radiation exposure. We propose a protocol including standard-dose abdominal CT and low-dose chest CT for the initial and follow-up stagings of primary gynecologic malignancy. The use of chest DR is unnecessary.     

Dose and image quality in the comparison of analogue and digital techniques in paediatric urology examinations

In paediatric radiology it has been recognised that children have a higher risk of developing cancer from the irradiation than adults (two to three times); therefore, increased attention has been directed towards the dose to the patient. In this study the effect on patient dose and image quality in replacing the exposure in micturating cystourethrography (MCUG) examinations with the stored fluoroscopy image has been investigated. In the intravenous urography (IVU) examination we compared analogue and digital image quality, but the dose measurements were performed on a phantom. Standard clinical X-ray equipment was used. Sixty-eight patients in each of two centres were studied for the MCUG. Doses were measured with a dose-area product (DAP) meter and the image quality was scored. A non-parametric statistical analysis was performed. For the IVU, a phantom was used in the dose measurements but clinical images were scored in the comparison between analogue and digital images. For the MCUG, replacing the exposure with stored fluoroscopy images lowered the DAP value from 0.77 to 0.50 Gy cm². The image quality did not show any difference between the techniques; however, if reflux was to be graded, exposure was needed. For the IVU, the doses could be lowered by a factor of 3 using digital techniques. The image quality showed no statistical difference between the two techniques. There is a potential for a substantial dose reduction in both MUCG and IVU examinations using digital techniques.     

Maximum recommended doses of local anesthetics: a multifactorial concept

The current recommendations regarding maximum doses of local anesthetics presented in textbooks, or by the responsible pharmaceutical companies, are not evidence based (ie, determined by randomized and controlled studies). Rather, decisions on recommending certain maximum local anesthetic doses have been made in part by extrapolations from animal experiments, clinical experiences from the use of various doses and measurement of blood concentrations, case reports of local anesthetic toxicity, and pharmacokinetic results. The common occurrence of central nervous system toxicity symptoms when large lidocaine doses were used in infiltration anesthesia led to the recommendation of just 200 mg as the maximum dose, which has remained unchanged for more than 50 years. In most cases, there is no scientific justification for presenting exact milligram doses or mg/kg doses as maximum dose recommendations. Instead, only clinically adequate and safe doses (ranges) that are block specific are justified, taking into consideration the site of local anesthetic injection and patient-related factors such as age, organ dysfunctions, and pregnancy, which may influence the effect and the pharmacokinetics of the local anesthetic. Epinephrine in concentrations of 2.5 to 5 microg/mL should be added to the local anesthetic solution when large doses are administered, providing there are no contraindications for the use of epinephrine. As a rule, conditions (eg, end-stage pregnancy, high age in epidural, or spinal block) or diseases (uremia) that may increase the rate of the initial uptake of the local anesthetic are indications to reduce the dose in comparison to one normally used for young, healthy, and nonpregnant adults. On the other hand, the reduced clearance of local anesthetics associated with renal, hepatic, and cardiac diseases is the most important reason to reduce the dose for repeated or continuous administration. The magnitude of the reduction should be related to the expected influence of the pharmacodynamic or pharmacokinetic change.