Postoperative transient reduced diffusion in the ipsilateral striatum and thalamus.

BACKGROUND AND PURPOSE: Restriction of diffusion has been reported in the early phase of secondary neuronal degeneration, such as wallerian degeneration. The purpose of this study was to investigate postoperative transient reduced diffusion in the ipsilateral striatum and thalamus as a remote effect of surgery. MATERIALS AND METHODS: Six hundred two postoperative MR imaging examinations in 125 patients after cerebral surgery were retrospectively reviewed, focusing on the presence of reduced diffusion in the striatum and/or thalamus. The distribution of reduced diffusion in the striatum was classified into 3 groups: anterior, central, and posterior. Reduced diffusion in the thalamus was also classified on the basis of the anatomic locations of the thalamic nuclei. Further follow-up MRI was available in all patients with postoperative reduced diffusion, and acute infarctions were excluded. The patient medical records were reviewed to evaluate neurologic status. RESULTS: Restriction of diffusion was observed in the striatum and/or thalamus ipsilateral to the surgical site in 17 patients (13.6%). The distribution of signal abnormality correlated with the location of the operation, in concordance with the architecture of the striatocortical and thalamocortical connections. Reduced diffusion was observed from days 7 to 46 after the operation, especially during days 8-21. The signal abnormalities completely resolved on follow-up examinations. The median follow-up period was 202 days (interquartile range, 76-487 days). CONCLUSIONS: Postoperative transient reduced diffusion in the ipsilateral striatum and/or thalamus likely represents an early phase of secondary neuronal degeneration based on its characteristic distribution and time course. Clinically, this reduced diffusion should not be mistaken for postoperative ischemic injury.

Radiation therapy combined with cis-diammine-glycolatoplatinum (nedaplatin) and 5-fluorouracil for Japanese stage II-IV esophageal cancer compared with cisplatin plus 5-fluorouracil regimen: a retrospective study.

To evaluate the treatment outcome of radiotherapy combined with cis-diammine-glycolatoplatinum (nedaplatin) plus 5-fluorouracil (5-FU) for esophageal cancer. From January 2000 to December 2004, a total of 12 esophageal cancer patients with locally advanced and metastatic esophageal cancer (stages II-IVB) were treated with radiation therapy (50.4 Gy) combined with nedaplatin (80 mg/m(2), bolus infusion) and 5-FU (800 mg/m(2)/24 h, continuous infusion for 4 days) (NDP group). We compared the data with those of patients during the same period receiving a different chemotherapy regimen consisting of cisplatin (75 mg/m(2), bolus infusion) and 5-FU (1000 mg/m(2)/24 h, continuous infusion for 4 days) (n = 29, CDDP group) combined with the same radiation therapy. The median survival period was 11.5 months in the NDP group and 13.1 months in the CDDP group. The overall survival rates at 1-, 2-, and 3-years were 40%, 13%, and 13% in the NDP group and 56%, 42%, and 8% in the CDDP group (P = 0.2472), respectively. Grade III and IV leukocytopenia was observed in six (50%) and none of the patients in the NDP group and 14 (48%) and seven (24%) in the CDDP group, respectively. Grade III thrombocytopenia was observed in three (25%) in the NDP group and four (14%) in the CDDP group. Radiation combined with nedaplatin and 5-FU is a safe and effective method for treating esophageal cancer. We recommend that NDP should be used rather than dose-reduction of CDDP combined with 5-FU in patients with impaired renal function as indicated by low creatinine clearance value (40-60 mL/min).

MR imaging of postischemic neuronal death in the substantia nigra and thalamus following middle cerebral artery occlusion in rats.

The goal of this study was to investigate apparent diffusion coefficient (ADC) and T(2) relaxation time (T(2)) in the substantia nigra and thalamus after middle cerebral artery occlusion in rats. In the substantia nigra ipsilateral to infarct, ADC was significantly lower and T(2) was significantly higher on the third and fourth days, but they did not change significantly on the first, second, eighth and 15th days. In the ipsilateral thalamus, ADC and T(2) did not change significantly between the first and fourth days, but were significantly lower on the eighth and 15th days. This combination of MR findings suggested that secondary degeneration in the thalamus was different from that in the substantia nigra.

Accurate preoperative evaluation of liver mass lesions without fine-needle biopsy.

Fine-needle biopsy (FNB) is associated with problems, such as tumor seeding, which are probably underestimated. The aim of this study was to validate prospectively the accuracy of our diagnostic work-up without FNB, for defining indications for surgery in a cohort of patients with focal liver lesions (FLLs). Between January 1997 and December 1998, 160 consecutive patients carrying 225 FLLs admitted to our department were evaluated prospectively. Preoperative diagnoses were established by means of clinical histories, serum tumor marker levels, ultrasonography, and spiral computed tomography (CT). Angiography, magnetic resonance imaging (MRI), and Lipiodol-CT were performed when it was considered necessary to plan the surgical strategy. All the patients underwent surgery and results of pathological examinations were obtained for all of them. The preoperative diagnoses of 221 of the 225 lesions (98.2%) were confirmed, and the indications for liver resection in 156 of the 160 patients (97.5%) were correct. The respective accuracy, sensitivity, specificity, and positive and negative predictive values were 99.6%, 100%, 98.9%, 99.3%, and 100% for diagnosis of hepatocellular carcinoma (HCC); 99.1%, 100%, 98.8%, 96.9%, and 100% for metastases; 99.6%, 100%, 99.5%, 91%, and 100% for cholangiocellular carcinomas (CCCs); all 100% for mixed HCC-CCCs; and 98.7%, 57.1%, 100%, 100%, and 98.6% for benign tumors. In view of these results, the fact that the real risks of FNB have yet to be established and the possibility that tumor seeding has a major impact on patient prognosis, the use of FNB should be drastically limited.

Amyotrophic lateral sclerosis: T2 shortening in motor cortex at MR imaging.

PURPOSE: To determine whether decreased signal intensity of the motor cortex (T2 shortening) at magnetic resonance (MR) imaging is a useful finding for supporting the diagnosis of amyotrophic lateral sclerosis (ALS). MATERIALS AND METHODS: High-field-strength (1.5-T) MR images of 15 patients (seven men and eight women, aged 28-80 years) and 49 neurologically normal age-matched control patients were examined for T2 shortening in the motor cortex. In addition, brains of patients with ALS were examined at autopsy. RESULTS: The MR images of 14 of the 15 patients showed T2 shortening in precentral cortices, while the images of all but one of the control patients showed no such finding. In three of eight brains at autopsy, sections from the precentral cortex showed sparsely distributed, intensely stained astrocytes and macrophages. CONCLUSION: Abnormal iron deposition associated with the degenerative process could be the source of T2 shortening, which is a useful MR imaging finding in the diagnosis of ALS.

[MR imaging of amyotrophic lateral sclerosis].

Magnetic resonance imaging (MR imaging) provides a sensitive method for mapping the normal and pathological distribution of iron in the brain. High field strength MR imaging (1.5 T) was used to evaluate eight patients with amyotrophic lateral sclerosis (ALS) and 49 neurological normal control patients. All eight ALS patients showed decreased signal intensity in the motor cortex on T2-weighted images, while only one of the normal control patients showed this finding. The results suggested that the decreased signal intensity in the motor cortex in ALS was caused by the deposition of iron in this area.

MR differentiation of hepatic haemangioma and hepatocellular carcinoma: value of delayed-phase Gd-DTPA enhanced images.

The efficacy of three different approaches (precontrast and delayed-phase postcontrast T1-weighted (T1-W) images, measurement of T2 value, and dynamic FLASH imaging) for differentiation between hepatic haemangiomas and hepatocellular carcinomas, was compared. Most haemangiomas (89%) showed iso- or hypointensity on precontrast T1-W images and hyperintensity on delayed-phase postcontrast T1-W images. By using both pre/postcontrast T1-W images and T2 measurement, 30 out of 32 lesions (94%) were correctly differentiated. The dynamic FLASH imaging did not significantly improve the overall accuracy although it played a critical role in a few problematic cases. It is concluded that the combination of pre/postcontrast T1-W images is a promising approach for differentiation of small hepatic tumours, and plays a complementary role with T2 measurement.

Hepatic cavernous hemangioma in patients at high risk for liver cancer.

Cavernous hemangioma of the liver occurring in patients at high risk for liver cancer has been reviewed. Twenty-four patients with hemangioma were encountered during the past 4 years. Five lesions over 3 cm in diameter were correctly diagnosed with enhanced CT alone. Definite CT findings were however obtained in only 6 out of 19 lesions smaller than 3 cm in diameter. Ultrasonography was the most sensitive method for picking up small liver tumors even when compared with angiography, but the findings were non-specific (an echogenic mass was noted in 14 of the 19 lesions). Magnetic resonance imaging (MRI) had almost the same sensitivity as ultrasound in detecting small hemangiomas, and a prolonged T2 was highly suggestive of the diagnosis (T2 over 80 ms in 8 of 11 lesions). The results suggest that combined use of non-invasive diagnostic modalities has sufficient reliability to make a diagnosis of cavernous hemangioma even in small hepatic lesions, in patients at high risk for liver cancer.