Diffusion-Weighted MRI as a Quantitative Imaging Biomarker in Colon Tumors

PURPOSE

To assess the use of quantitative diffusion-weighted MRI (DW-MRI) as a diagnostic imaging biomarker in differentiating between benign colon adenoma, early, and advanced cancer of the colon, as well as predicting lymph node involvement, and finally comparing mucinous-producing colon cancer with adenomas and non-mucinous colon cancer.

METHOD

Patients with a confirmed tumor on colonoscopy were eligible for inclusion in this study. Using a 3.0 Tesla MRI machine, the main tumor mean apparent diffusion coefficient (mADC) was obtained. Surgically resected tumor specimens served as an endpoint, except in mucinous colon cancers, which were classified based on T2 images.

RESULTS

A total of 152 patients were included in the study population. The mean age was 71 years. A statistically significant mADC mean difference of -282 × 10-6 mm2/s [-419--144 95% CI, p < 0.001] was found between colon adenomas and early colon cancer, with an AUC of 0.80 [0.68-0.93 95% CI] and an optimal cut off value of 1018 × 10-6 mm2/s. Only a small statistically significant difference (p = 0.039) in mADC was found between benign tumors and mucinous colon cancer. We found no statistical difference in mADC mean values between early and advanced colon cancer, and between colon cancer with and without lymph node involvement.

CONCLUSION

Quantitative DW-MRI is potentially useful for determining whether a colonic tumor is benign or malignant. Mucinous colon cancer shows less diffusion restriction when compared to non-mucinous colon cancer, a potential pitfall.

Ultrasound assessment of testicular volume - An interobserver variability study

BACKGROUND

Ultrasonography measurement of the testicles and subsequent calculation of the testicular volume is recommended as a part of a standard scrotal ultrasound examination. The interobserver variability of testicular volume measurement has implications for surgical recommendations. Therefore, this study aimed to investigate the interobserver variability in the measurement of testicular volume.

METHODS

Interobserver variability was established by comparing testicular measurements performed by two observers on the same patient during the same clinical appointment. The observers were blinded to each other's measurements. Testicular volume was calculated using the Lambert formula: length x width x height x 0.71. A total of three observers, A, B and C, participated in the study. The observers had between 4 to 20 years' experience with scrotal ultrasound examinations.

RESULTS

In total, 24 patients' were included (48 testicles). The patient´s mean age was 43 years (range 19-75 years). The overall mean right testicular volume was 19.8 ml (range 7.3-31.6 ml), and the left was 20.1 ml (range 7.1-36.1 ml). The interclass correlation coefficient (ICC) between observer A and B was excellent (ICC= 0.98, CI:0.92-0.99), between observer A and C, was excellent (ICC=0.91, CI: 0.77-0.97) and between B and C good (ICC=0.82, CI:0.51-0.93).

CONCLUSION

Variability in estimating testicular volume is low, with interobserver agreement ranging from good to excellent. Ultrasound provides a highly reproducible tool to determine testicular volume.

Diffusion-Weighted MRI in Patients with Testicular Tumors—Intra- and Interobserver Variability

In general, magnetic resonance (MR) diffusion-weighted imaging (DWI) has shown potential in clinical settings. In testicles parenchyma, the DW imaging helps differentiate and characterize benign from malignant lesions. Placement and size of the region of interest (ROI) may affect the ADC value. Therefore, the aim of this study was to investigate the intra- and interobserver variability in testicular tumors when measuring ADC using various types of regions of interest (ROI). Two observers performed the ADC measurements in testicular lesions based on three ROI methods: (1) whole volume, (2) round, and (3) small sample groups. Intra- and interobserver variability was analyzed for all ROI methods using intraclass correlation coefficients (ICC) and bland-altman plots. The two observers performed the measurements twice, three months apart. A total of 26 malignant testicle tumors were included. Interobserver agreement was excellent in tumor length (ICC = 0.98) and tumor width (ICC = 0.98). In addition, intraobserver agreement was excellent in tumor length (ICC = 0.98) and tumor width (ICC = 0.99). The whole volume interobserver agreement in the first reading was excellent (ICC = 0.93). Round ADC had an excellent (ICC = 0.93) and fair (ICC = 0.58) interobserver agreement, in the first and second reading, respectively. Interobserver agreement in ADC small ROIs was good (ICC = 0.87), and good (ICC = 0.78), in the first and second reading, respectively. Intraobserver agreement varied from fair, good to excellent agreement. The ROI method showed varying inter- and intraobserver agreement in ADC measurement. Using multiple small ROI conceded the highest interobserver variability, and, thus, the whole volume or round seem to be the preferable methods.

Intra- and Interobserver Variability in Magnetic Resonance Imaging Measurements in Rectal Cancer Patients

Colorectal cancer is the second most common cancer in Europe, and accurate lymph node staging in rectal cancer patients is essential for the selection of their treatment. MRI lymph node staging is complex, and few studies have been published regarding its reproducibility. This study assesses the inter- and intraobserver variability in lymph node size, apparent diffusion coefficient (ADC) measurements, and morphological characterization among inexperienced and experienced radiologists. Four radiologists with different levels of experience in MRI rectal cancer staging analyzed 36 MRI scans of 36 patients with rectal adenocarcinoma. Inter- and intraobserver variation was calculated using interclass correlation coefficients and Cohens-kappa statistics, respectively. Inter- and intraobserver agreement for the length and width measurements was good to excellent, and for that of ADC it was fair to good. Interobserver agreement for the assessment of irregular border was moderate, heterogeneous signal was fair, round shape was fair to moderate, and extramesorectal lymph node location was moderate to almost perfect. Intraobserver agreement for the assessment of irregular border was fair to substantial, heterogeneous signal was fair to moderate, round shape was fair to moderate, and extramesorectal lymph node location was substantial to almost perfect. Our data indicate that subjective variables such as morphological characteristics are less reproducible than numerical variables, regardless of the level of experience of the observers.

Spontaneous dissolution of a cyst located within the septum pellucidum in a patient with sarcoidosis: a case report

Sarcoidosis is a granulomatous multisystem disease of unknown etiology. Typically, the disease affects the lungs, causing enlargement of the mediastinal lymph nodes, but other organs can be affected. Neurosarcoidosis is reported in 5-10% of the patients. This case represents a 39-year-old male patient diagnosed with lung sarcoidosis. Due to neurological symptoms, a contrast-enhanced cerebral magnetic resonance imaging was performed. Neurosarcoidosis was presented with meningeal enhancement adjacent to a cyst located within the cavum septum pellucidum. The cyst dissolved spontaneously within six months. The finding of a cyst located within the septum pellucidum is rare.