Treatment response of colorectal cancer liver metastases to neoadjuvant or conversion therapy: a prospective multicentre follow-up study using MRI, diffusion-weighted imaging and 1H-MR spectroscopy compared with histology (subgroup in the RAXO trial)

BACKGROUND

Colorectal cancer liver metastases respond to chemotherapy and targeted agents not only by shrinking, but also by morphologic and metabolic changes. The aim of this study was to evaluate the value of advanced magnetic resonance imaging (MRI) methods in predicting treatment response and survival.

PATIENTS AND METHODS

We investigated contrast-enhanced MRI, apparent diffusion coefficient (ADC) in diffusion-weighted imaging and 1H-magnetic resonance spectroscopy (1H-MRS) in detecting early morphologic and metabolic changes in borderline or resectable liver metastases, as a response to first-line neoadjuvant or conversion therapy in a prospective substudy of the RAXO trial (NCT01531621, EudraCT2011-003158-24). MRI findings were compared with histology of resected liver metastases and Kaplan-Meier estimates of overall survival (OS).

RESULTS

In 2012-2018, 52 patients at four Finnish university hospitals were recruited. Forty-seven patients received neoadjuvant or conversion chemotherapy and 40 liver resections were carried out. Low ADC values (below median) of the representative liver metastases, at baseline and after systemic therapy, were associated with partial response according to RECIST criteria, but not with morphologic MRI changes or histology. Decreasing ADC values following systemic therapy were associated with improved OS compared to unchanged or increasing ADC, both in the liver resected subgroup (5-year OS rate 100% and 34%, respectively, P = 0.022) and systemic therapy subgroup (5-year OS rate 62% and 23%, P = 0.049). 1H-MRS revealed steatohepatosis induced by systemic therapy.

CONCLUSIONS

Low ADC values at baseline or during systemic therapy were associated with treatment response by RECIST but not with histology, morphologic or detectable metabolic changes. A decreasing ADC during systemic therapy is associated with improved OS both in all patients receiving systemic therapy and in the resected subgroup.

Correlation between apparent diffusion coefficient value on diffusion-weighted MR imaging and Gleason score in prostate cancer

OBJECTIVES

To investigate whether diffusion-weighted imaging (DWI) apparent diffusion coefficient (ADC) correlates with prostate cancer aggressiveness and further to compare the diagnostic performance of ADC and normalized ADC (nADC: normalized to non-tumor tissue).

PATIENTS AND METHODS

Thirty pre-treatment patients (mean age, 69years; range: 59-78years) with prostate cancer underwent magnetic resonance imaging (MRI) examination, including DWI with three b values: 50, 400, and 800s/mm². Both ADC and nADC were correlated with the Gleason score obtained through transrectal ultrasound-guided biopsy.

RESULTS

The tumor minimum ADC (ADC_min: the lowest ADC value within tumor) had an inverse correlation with the Gleason score (r=-0.43, P<0.05), and it was lower in patients with Gleason score 3+4 than in those with Gleason score 3+3 (0.54±0.11×10³mm²/s vs. 0.64±0.12×10^-3mm²/s, P<0.05). Both the nADC_min and nADC_mean correlated with the Gleason score (r=-0.52 and r=-0.55, P<0.01; respectively), and they were lower in patients with Gleason score 3+4 than those with Gleason score 3+3 (P<0.01; respectively). Receiver operating characteristic (ROC) analysis showed that the area under the ROC curve was 0.765, 0.818, or 0.833 for the ADC_min, nADC_min, or nADC_mean; respectively, in differentiating between Gleason score 3+4 and 3+3 tumors.

CONCLUSION

Tumor ADC_min, nADC_min, and nADC_mean are useful markers to predict the aggressiveness of prostate cancer.

Magnetic Resonance Imaging of Acute Scrotum

Background and Aims:

The aim of the pilot study was to evaluate the feasibility of dynamic contrast enhanced (CE)-magnetic resonance imaging (MRI) in the detection of testicular ischemia and its ability to differentiate testicle torsion from other causes of acute scrotum.

Material and Methods:

Seventeen boys or young men with an acute scrotum were included in the prospective study during the time period from October 2001 to December 2005. The median age of the patients was 16,4 (7–44) years. The duration of the symptoms preceding the MRI study varied from six hours to 30 days. The study protocol included physical examination by a surgeon, laboratory tests and Doppler ultrasound (DUS) and finally testicles were imaged by using a 1,5 T MRI scanner; T1-weighted and diffusion weighted images were produced. The gadolinium uptake, reported as the region of interest (ROI) perfusion values and presented as curves, was compared between the affected and contralateral testicle. In testicles with normal blood circulation the ROI values increased during the imaging time. Nine patients were operated on, because the spermatic cord torsion could not be excluded by clinical or DUS findings.

Results and Conclusions:

All the normal testicles gave increasing ROI values meanwhile all three testicles with torsion gave constantly low values referring to no perfusion. Other causes of acute scrotum, such as epididymitis and torsion of testicular appendage seemed to be related with normal perfusion. Dynamic CE-MRI seems to show reliably ischemia of testicle and thus it may be helpful in selecting patients with acute scrotum for urgent operation.

Magnetic resonance renography findings and their clinical associations in nephropathia epidemica

PURPOSE

To evaluate, with magnetic resonance renography (MRR), the dynamics of renal function in patients with nephropathia epidemica (NE) and to correlate the findings with the clinical course of NE.

MATERIAL AND METHODS

MRR was performed on 20 hospitalized NE patients during the acute phase of the disease. A repeat MRR study was done 5-8 months later. Primary and repeat MRR studies were compared and functional findings evaluated.

RESULTS

The uptake slope of the contrast enhancement curve was abnormal in the primary study in 14 patients, maximum level of enhancement in 11, decreasing slope of contrast enhancement curve in 14, and signal drop at time in 10 patients when the primary and repeat studies were compared. The greater change in the uptake slope of contrast enhancement, maximum level of enhancement, decreasing slope of enhancement, and signal drop at time between primary and repeat MRR studies evinced a mild association with the severity of clinical renal insufficiency and fluid volume overload.

CONCLUSION

Measurable functional MRR findings were recorded in 14/20 NE patients. The severity of the findings was mildly associated with the degree of clinical renal insufficiency and fluid volume overload.

Magnetic resonance imaging of experimental testicular torsion

We investigated the feasibility of contrast enhanced (CE)-dynamic magnetic resonance imaging (MRI) for the detection of testicular torsion induced hypoperfusion in an experimental rat model. Adult Sprague-Dawley rats were subjected to unilateral testicular torsion of 360 or 720 degrees. After 1 h, the tail veins of the anaesthetized rats were cannulated and T2 -, diffusion-weighted and T1-weighted CE-dynamic MRI were subsequently performed by a 1.5 T MRI scanner. On apparent diffusion coefficient (ADC) images, the region of interest values of the ischaemic and control testes was compared. From CE-dynamic MR images, the maximal slopes of contrast enhancement were calculated and compared. In testicular torsion of 360 degrees, the maximal slope of contrast enhancement was 0.072%/s vs. 0.47%/s in the contralateral control testis (p < 0.001). A torsion of 720 degrees diminished the slope of contrast enhancement to 0.046%/s vs. 0.37%/s in the contralateral testis (p < 0.001). Diminished blood flow during torsion also followed in decreased ADC values in both 360 degrees (12.4% decrease; p < 0.05) and 720 degrees (10.8% decrease; p < 0.001) of torsion. Torsion of the testis causes ipsilateral hypoperfusion and decreased gadolinium uptake in a rat model that can be easily detected and quantified by CE-dynamic MRI. In diffusion-weighted MRI images, acute hypoperfusion results in a slight decrease of ADC values. Our results suggest that CE-dynamic MRI in combination with diffusion-weighted MRI can be used to detect compromised blood flow due to acute testicular torsion.

Renal MRI findings and their clinical associations in nephropathia epidemica: analysis of quantitative findings

Morphologic renal magnetic resonance imaging (MRI) findings in patients with nephropathia epidemica (NE) were evaluated, and these findings were correlated with the clinical course of NE. Renal MRI was performed in 20 hospitalized NE patients during the acute phase of their disease. A repeat MRI study was made 5-8 months later. Renal parenchymal volume, renal length and parenchymal thickness were decreased in all patients in the repeat study. Edema/fluid collections were found bilaterally in 16 patients in the primary MRI study. Greater change in parenchymal volume, renal length and parenchymal thickness between the primary and the repeat MRI study as well as the presence of edema/fluid collections in the primary study evinced mild association with clinical fluid volume overload, high blood pressure level, inflammation, thrombocytopenia and severe clinical renal insufficiency. Change in parenchymal volume was associated with a severe clinical course more markedly than the other MRI findings. Measurable renal MRI changes occurred in every NE patient. The severity of the findings in MRI evinced mild association with clinical fluid volume overload, high blood pressure level, inflammation, thrombocytopenia and severe clinical renal insufficiency. Based on this study and our previous ultrasound (US) findings, we prefer US as the primary examination mode in NE patients.

Vertebral epidural arteriovenous fistula and radicular pain in neurofibromatosis type I

A minor trauma caused opening of an arteriovenous fistula between the right vertebral artery and cervical spinal epidural venous plexus in a patient with neurofibromatosis Type I. Subsequent dilation of the plexus caused compression of the spinal cord and radicular symptomology of the right upper extremity. The single-hole fistula and its arterial feeder were filled with electrodetachable coils via an intra-arterial approach. This lead into shrinkage of the plexus, reformation of the cord caliber and full and stable clinical recovery. The achieved endovascular occlusion of the fistula proved to be permanent on follow-up.

Magnetic resonance imaging compared to ultrasonography in fetal weight and volume estimation in diabetic and normal pregnancy

OBJECTIVE

To estimate fetal volume and weight in diabetic and normal pregnancy using high-resolution magnetic resonance imaging.

METHODS

T1-weighted magnetic resonance imaging was combined with semiautomatic segmentation technique. The accuracy of fetal volume estimations thus obtained was compared with conventional ultrasound-based weight estimations in ten pregnant women with insulin-dependent diabetes mellitus and ten women with normal pregnancy. Examinations were made within 48 hours before delivery.

RESULTS

Ultrasound-based estimations of fetal weight showed a correlation rate of r=0.77 with the actual birth weights in the whole material, while volume determinations based on magnetic resonance imaging showed a significantly better correlation rate of r=0.95. Diabetic women did not differ from the normal pregnancy group with regard to birth weight or the accuracy of weight estimations.

CONCLUSIONS

High-resolution magnetic resonance imaging combined with semiautomatic segmentation software was found to be accurate in determining fetal volume and, consequently, better than conventional ultrasound-based techniques in estimating fetal weight. The use of magnetic resonance imaging in fetal weight estimation may be recommended for clinical situations where an accurate weight estimate is considered essential.

Nasal airway volumetric measurement using segmented HRCT images and acoustic rhinometry

Semiautomatic segmentation methods using High Resolution Computed Tomography (HRCT) or Magnetic Resonance Imaging give accurate and reproducible volumetric measurements in various intracranial diseases. In this prospective study, for the first time in literature, with the help of a new semiautomatic segmentation technique and coronal HRCT, we correlated the volumes and cross-sectional areas of the nasal cavity with those obtained by clinical acoustic rhinometry in 14 patients with chronic sinusitis. The measurements obtained by both techniques showed statistically significant correlations between volumes in the anterior and middle parts, but statistically poor correlations between the volumes in the posterior part of the nasal cavity. Coronal HRCT and our new microcomputer applicable semiautomatic segmentation software proved compatible with daily clinical practice. Based on the promising results of our study, we recommend the use of this technique in the validation studies of acoustic rhinometry and in complicated cases as a complementary examination in the evaluation of nasal cavity.

Applicability of semi-automatic segmentation for volumetric analysis of brain lesions

This project involves the development of a fast semi-automatic segmentation procedure to make an accurate volumetric estimation of brain lesions. This method has been applied in the segmentation of demyelination plaques in Multiple Sclerosis (MS) and right cerebral hemispheric infarctions in patients with neglect. The developed segmentation method includes several image processing techniques, such as image enhancement, amplitude segmentation, and region growing. The entire program operates on a PC-based computer and applies graphical user interfaces. Twenty three patients with MS and 43 patients with right cerebral hemisphere infarctions were studied on a 0.5 T MRI unit. The MS plaques and cerebral infarctions were thereafter segmented. The volumetric accuracy of the program was demonstrated by segmenting Magnetic Resonance (MR) images of fluid filled syringes. The relative error of the total volume measurement based on the MR images of syringes was 1.5%. Also the repeatability test was carried out as inter-and intra-observer study in which MS plaques of six randomly selected patients were segmented. These tests indicated 7% variability in the inter-observer study and 4% variability in the intra-observer study. Average time used to segment and calculate the total plaque volumes for one patient was 10 min. This simple segmentation method can be utilized in the quantitation of anatomical structures, such as air cells in the sinonasal and temporal bone area, as well as in different pathological conditions, such as brain tumours, intracerebral haematomas and bony destructions.