Volume estimation of multicellular colon carcinoma spheroids using Cavalieri's principle

Distant infusion of saline may enlarge coagulation volume during radiofrequency ablation of liver tissue using cool-tip electrodes without impairing predictability

OBJECTIVE

Our aim was to evaluate the capability of a Cool-tip electrode to create larger coagulation volumes combined with a low-flow (0.1 mL/min) perfusion of hypertonic saline at a distance of 2 mm (hybrid applicator) without reducing either predictability or sphericity of the coagulation zone.

MATERIALS AND METHODS

A total of 48 radiofrequency ablations were performed on a total of 12 adult pigs: 24 with the Cool-tip (group 1) and 24 with the hybrid applicator (group 2). Volumes and diameters were assessed both macroscopically and with imaging techniques (ultrasound and MRI). Digital reconstruction techniques were also used. Reproducibility of the coagulations was assessed by means of the coefficient of variation.

RESULTS

The macroscopic assessment showed a significantly larger coagulation zone in group 2 than in group 1, both with (19.40 ± 11.38 cm(3) vs 9.16 ± 5.62 cm(3); p < 0.001) and without (19.54 ± 11.39 cm(3) vs 9.21 ± 5.74 cm(3); p < 0.001) digital reconstruction. Differences were also significant in the MRI assessment. The minimum transverse diameter was also significantly (p < 0.01) larger in group 2 than group 1: 2.46 ± 0.61 versus 1.86 ± 0.55 cm for macroscopic assessment, 2.33 ± 0.96 versus 1.69 ± 0.53 cm for ultrasound, and 2.41 ± 0.58 versus 1.8 ± 0.52 cm for MRI. The coefficient of variation was similar in both groups.

CONCLUSION

The results suggest that low-flow perfusion of hypertonic saline at 2 mm from a Cool-tip electrode could increase coagulation zone volume without reducing predictability.

Retrospective measurement of different size parameters of non-radiated rectal cancer on MR images and pathology slides and their comparison

There are no non-invasive methods to assess the real tumor size in rectal cancer prior to surgery, especially following radio/chemotherapy. Magnetic resonance imaging is gaining increasing acceptance as the primary modality at many centers for evaluation of pelvic malignancies including rectal cancers. The aim of this study was to evaluate if the tumor size as assessed by stereological or metric means on MRI correlates to the corresponding pathologic findings. To our knowledge, no such previous work has been reported in the literature. From the Cancer Register Center, 18 patients in the age range of 39-90 years with rectal cancer who had complete preoperative MR with subsequent giant section pathological examinations of the resected bowel were included. The tumor size was measured on MR and histopathologic specimen using both a stereologic and a metric mode. The measured parameters included the maximum transverse area occupied by the tumor, thickness, width, and the length of tumor and the volume of the tumor measured in two different fashions by the product of area and length (al) or the product of thickness, width, and length (twl). The depth of tumor infiltration (T) and presence of local lymph node metastases (N) were also separately evaluated on the histopathologic specimen. There were 1, 4, 12, and 1 patients with tumor stages T1, T2, T3, and T4, respectively. The mean thickness, width, length, area, and volumes, al and twl, were 1.62, 2.8, and 4.78 cm, and 4.72 cm2, 26.29 cm3, and 20.07 cm3, respectively. Regression curves were drawn for above-mentioned parameters. They showed some correlation with square correlation coefficient measuring between 0.38 and 0.82. The best correlation was seen for area (0.75) and volume measured by the product of area and length of the tumor (0.82). With the formula proposed from this material, we assume that rectal tumors can be measured on MR images using a metric model, especially area and the volume (the product of area and length), and then extrapolated to what we would expect from pathology, hence providing us with a tool where we could measure tumor response after neoadjuvant therapy.

A strikingly constant ratio exists between Langerhans cells and other epidermal cells in human skin. A stereologic study using the optical disector method and the confocal laser scanning microscope

Langerhans cells play an important part in the immune surveillance of the human epidermis. Therefore, a certain distribution and numerical relationship to other epidermal cells can be expected. To quantify epidermal Langerhans cells population extensive studies have been performed using two-dimensional quantification methods on vertical sections or epidermal sheet preparations. Whereas methods using vertical sections were complicated considerably by the sampling procedure, the dendritic shape, and the suprabasal, nonrandom distribution of Langerhans cells, epidermal sheet preparations have their limitations regarding the numerical relationship of Langerhans cells to total epidermal cells and the epidermal morphology as such. In order to improve the validity of data the three-dimensional dissector method combined with confocal laser scanning microscopy has been applied to quantify the number of Langerhans cells and other epidermal cell nuclei per volume unit in cryosections of 24 punch biopsies of normal breast skin of eight women. Furthermore, the ratio of Langerhans cells to other epidermal cells, their number per biopsy, and per skin surface area were calculated. To minimize the bias by shrinkage the reference volume was estimated using Cavalieri's principle. A constant ratio of one Langerhans cells to 53 other epidermal cells was identified in breast skin (interindividual correlation coefficient: 0.952, p < 0.0001). Thus, Langerhans cells represent 1.86% of all epidermal cells; however, a wide interindividual range was found for the number of Langerhans cells per mm2 (912-1806; mean +/- SD 1394 +/- 321) and other epidermal cells per mm2 (47,315-104,588; mean +/- SD 73,952 +/- 19,426). This explains the conflicting results achieved by conventional morphometric assessments relating cell numbers to skin surface area, ignoring the varying thickness of the epidermis. The surprisingly constant relationship of Langerhans cells to other epidermal cells stresses the hypothesis of an epidermal Langerhans cells unit where one Langerhans cells seems to be responsible for the immune surveillance of 53 epidermal cells.