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To retrospectively identify risk factors that may impede a favorable clinical outcome after thermocoagulation for osteoid osteoma.Informed consent (permission for the procedure and permission to use patient data for analysis) was obtained from all patients who met study criteria, and institutional review board did not require approval. Analysis included age, sex, size and location of osteoid osteoma, presence of calcified nidus, number of needle positions used for coagulation, coagulation time, accuracy of needle position, learning curve of radiologist, and previous treatment in 95 consecutive patients with osteoid osteoma treated with thermocoagulation. With chi(2) analysis, Fisher exact test, or unpaired Student t test and logistic regression analysis, 23 unsuccessfully treated patients were compared with 72 successfully (pain-free) treated patients.Parameters associated with decreased risk for treatment failure were advanced age (mean age, 24 years in treatment success group vs 20 years in treatment failure group) and increased number of needle positions during thermocoagulation. Estimated odds ratios were, respectively, 0.93 (95% confidence interval: 0.88, 0.99) and 0.10 (95% confidence interval: 0.02, 0.41). Patients with a lesion of 10 mm or larger seemed at risk for treatment failure (odds ratio = 2.68), but the 95% confidence interval of 0.84 to 8.52 included the 1.00 value. Needle position was inaccurate in nine of 23 patients with treatment failure; only one needle position was used in eight of these nine patients. Lesion location, calcification, sex, coagulation time, radiologist's learning curve, and previous treatment were not risk factors.Multiple needle positions reduce the risk of treatment failure in all patients and should especially, but not exclusively, be used in large (or =10-mm) lesions or lesions that are difficult to engage to reduce the risk for unsuccessful treatment.

To determine the relationship between the size of hepatic metastases, the standard of reference, and the reported detection rate in patients with colorectal cancer.With use of a MEDLINE search (January 1994 to January 2001), articles were selected that contained original results on detection of hepatic metastases of colorectal cancer, categorized for size in at least two categories, with use of helical computed tomography (CT), helical CT at arterial portography, or magnetic resonance imaging. Results were compared with the size distribution of hepatic metastases in 47 consecutive patients with colorectal carcinoma, which were detected by using a combination of intraoperative ultrasonography (US) and palpation.Seven studies met all predefined criteria. Four studies involved intraoperative US in all patients and demonstrated a significant negative correlation (-0.988) between detection rate and fraction of small metastases. These studies had a higher fraction and lower detection rate of small metastases and a lower overall detection rate. A majority (58% [145 of 252]) of metastases in the study population were smaller than 20 mm.Few articles adequately describe the standard of reference and size distribution of hepatic lesions. Hepatic metastases of colorectal cancer are frequently smaller than 20 mm. When the standard of reference is suboptimal, many small metastases are excluded from analysis, and detection rates are therefore inflated.

To retrospectively compare different magnetic resonance (MR) imaging techniques and pulse sequences for the depiction of brain injury in neonatal hypoxic-ischemic encephalopathy.The institutional review board approved this retrospective study and waived informed consent. Term-born neonates underwent MR imaging within 10 days after birth because of perinatal asphyxia. Two investigators separately and retrospectively evaluated T1-weighted, T2-weighted, fluid-attenuated inversion recovery (FLAIR), diffusion-weighted, and T1-weighted contrast material-enhanced MR images for presence of hypoxic-ischemic injury patterns. Interobserver agreement between the raters for visualizing abnormalities on images obtained with the individual pulse sequences was analyzed. Individual assessments were compared with the consensus reading (reference standard) to determine which techniques were best for visualizing hypoxic-ischemic damage. Last, which combination of pulse sequences had the best performance for visualizing certain injury patterns was evaluated. All analyses were repeated for infants imaged within 4 days after birth and those imaged between 4 and 10 days after birth.Forty term-born neonates (22 boys; gestational age, 37 weeks to 42 weeks 2 days) were included. Interobserver agreement was moderate for all pulse sequences (intraclass correlation coefficient [ICC], 0.52-0.73). As compared with the reference standard, T1-weighted imaging performed best in both groups (infants imagedor = 4 days and those imaged4 days after birth) for lesions in the basal ganglia, thalamus, and posterior limb of the internal capsule (ICC, 0.93), as well as for punctate white matter lesions (ICC, 0.88). For infarction, diffusion-weighted images were scored best in both groups (ICC, 0.86). For nonpunctate white matter lesions, T2-weighted images were scored as good in both groups (ICC, 0.59). Adding FLAIR and contrast-enhanced imaging to the combination of T1- and T2-weighted imaging and diffusion-weighted imaging did not contribute to detection of hypoxic-ischemic brain damage.The combination of T1- and T2-weighted MR imaging and diffusion-weighted imaging is best for detecting hypoxic-ischemic brain lesions in the early neonatal period in term-born infants.