Cellular Density Evaluation for Malignant Lymphoma Using Equivalent Cross-Relaxation Rate Imaging - Initial Experience

OBJECTIVE: Equivalent cross-relaxation rate (ECR) imaging is an MRI technique used to evaluate quantitatively a change in the protein-water interaction. We aimed to evaluate retrospectively the usefulness of ECR imaging for the histologic classification of malignant lymphoma (ML). MATERIALS AND METHODS: Institutional Review Board approval was obtained and all patients provided informed consent. The study subjects included 15 patients with untreated ML who were histologically diagnosed with follicular lymphoma (FL; n = 8) or diffuse large B-cell lymphoma (DLBCL; n = 7). All patients underwent ECR imaging and the offset frequency was set at 7 ppm. RESULTS: The median ECR values were 71% (range; 60.7 to 75.5) in FL and 54% (50.8 to 59.4) in DLBCL (p = 0.001). The median cellular density was 1.5 +/- 0.17 x 10(6) / mm2 in FL and 1.0 +/- 0.70 x 10(6) / mm2 in DLBCL (p = 0.001). The correlation coefficient between the ECR values and cellular density in ML was 0.88 (p = 0.001). In FL and DLBCL, assuming ECR value cut-off points of 60%, both sensitivity and specificity were 100%. CONCLUSION: A strong correlation between ECR and cellular density in ML is demonstrated and the ECR may be a useful technique to differentiate between FL and DLBCL.

Detectability of Various Sizes of Honeycombing Cysts in an Inflated and Fixed Lung Specimen: the Effect of CT Section Thickness

OBJECTIVE: We wanted to clarify the relationship between the visibility of air cysts on CT images, the CT slice thickness and the size of the air cysts, with contact radiographs as the gold standard, for the accurate evaluation of honeycomb cysts. MATERIALS AND METHODS: An inflated and fixed autopsied lung having idiopathic interstitial pneumonia was evaluated. The corresponding air cysts were identified on the contact radiographs of a 0.5 mm-thick-section specimen and also on the CT images of three different kinds of section thickness: 0.5, 1.0 and 2.5 mm. The maximal diameters of the air cysts were measured under a stereomicroscope. RESULTS: A total of 341 air cysts were identified on the contact radiograph, and they were then evaluated. Sixty-six percent of air cysts 1 to 2 mm in diameter were detected by 0.5 mm slice thickness CT, while only 34% and 8% were detected by 1.0 and 2.5 mm slice thickness CT, respectively. Only 28% and 22% of air cysts less than 1 mm in diameter were detected by 0.5 and 1.0 mm slice thickness CT, respectively. CT with a 2.5 mm slice thickness could not demonstrate air cysts less than 1 mm in diameter. CONCLUSION: The CT detection rate of honeycombing is significantly influenced both by the slice thickness and the size of the air cysts.