Monitoring In-Vivo the Mammary Gland Microstructure during Morphogenesis from Lactation to Post-Weaning Using Diffusion Tensor MRI.

Lactation and the return to the pre-conception state during post-weaning are regulated by hormonal induced processes that modify the microstructure of the mammary gland, leading to changes in the features of the ductal / glandular tissue, the stroma and the fat tissue. These changes create a challenge in the radiological workup of breast disorder during lactation and early post-weaning. Here we present non-invasive MRI protocols designed to record in vivo high spatial resolution, T2-weighted images and diffusion tensor images of the entire mammary gland. Advanced imaging processing tools enabled tracking the changes in the anatomical and microstructural features of the mammary gland from the time of lactation to post-weaning. Specifically, by using diffusion tensor imaging (DTI) it was possible to quantitatively distinguish between the ductal / glandular tissue distention during lactation and the post-weaning involution. The application of the T2-weighted imaging and DTI is completely safe, non-invasive and uses intrinsic contrast based on differences in transverse relaxation rates and water diffusion rates in various directions, respectively. This study provides a basis for further in-vivo monitoring of changes during the mammary developmental stages, as well as identifying changes due to malignant transformation in patients with pregnancy associated breast cancer (PABC).

Can diffusion tensor anisotropy indices assist in breast cancer detection?

PURPOSE: To evaluate whether the various anisotropy indices derived from breast diffusion tensor imaging (DTI) can characterize the healthy breast structure and differentiate cancer from normal breast tissue. MATERIALS AND METHODS: Six healthy volunteers and retrospectively selected 24 breast cancer patients were imaged at 3T. DTI included two b-values 0 and 700 sec/mm2 with 20-64 gradient directions and TE of 120 or 90 msec. The normalized anisotropy indices: fractional anisotropy (FA), relative anisotropy (RA), and 1-volume ratio (1-VR), as well as the absolute maximal anisotropy index (λ1 -λ3 ) were compared. RESULTS: The spatial distribution of the various anisotropy indices in healthy volunteers exhibited a high congruence (Pearson correlation coefficients range: 0.79-1.0). All indices showed a statistically significant reduction (P < 0.001) following shortening of the diffusion time. Significantly lower λ1 -λ3 values were found in cancers as compared to normal breast tissue (P < 6.0 × 10-7 ), while the values of the normalized indices in cancers were not significantly different from those in normal breast tissue (P < 0.65 for FA, P < 0.6 for RA, and P < 0.2 for 1-VR). The contrast-to-noise ratio of λ1 -λ3 was significantly higher (P < 0.001) than those of the normalized anisotropy indices, and the area under the curve in a receiver operating characteristic analysis exhibited the highest value for λ1 -λ3 (0.89 ± 0.04 vs. 0.51-0.54 for the other anisotropy indices). CONCLUSION: Water diffusion anisotropy in the healthy breast can be similarly mapped by the normalized indices and by λ1 -λ3 . However, the normalized anisotropy indices fail to differentiate cancer from normal breast tissue, whereas λ1 -λ3 can assist in differentiating cancer from normal breast tissue. J. Magn. Reson. Imaging 2016;44:1624-1632.

Overcoming limitations in diffusion-weighted MRI of breast by spatio-temporal encoding.

PURPOSE: Evaluating the usefulness of diffusion-weighted spatio-temporal encoding (SPEN) methods to provide quantitative apparent diffusion coefficient (ADC)-based characterizations of healthy and malignant human breast tissues, in comparison with results obtained using techniques based on spin-echo echo planar imaging (SE-EPI). METHODS: Twelve healthy volunteers and six breast cancer patients were scanned at 3T using scanner-supplied diffusion-weighted imaging EPI sequences, as well as two fully refocused SPEN variants programmed in-house. Suitable codes were written to process the data, including calculations of the actual b-values and retrieval of the ADC maps. RESULTS: Systematically better images were afforded by the SPEN scans, with negligible geometrical distortions and markedly weaker ghosting artifacts arising from either fat tissues or from strongly emitting areas such as cysts. SPEN-derived images provided improved characterizations of the fibroglandular tissues and of the lesions' contours. When translated into the calculation of the ADC maps, there were no significant differences between the mean ADCs derived from SPEN and SE-EPI: if reliable images were available, both techniques showed that ADCs decreased by nearly two-fold in the malignant lesion areas. CONCLUSION: SPEN-based sequences yielded diffusion-weighted breast images with minimal artifacts and distortions, enabling the calculation of improved ADC maps and the identification of decreased ADCs in malignant regions.

Diffusion-tensor MR imaging of the breast: hormonal regulation.

PURPOSE: To investigate the parameters obtained with magnetic resonance (MR) diffusion-tensor imaging (DTI) of the breast throughout the menstrual cycle phases, during lactation, and after menopause, with and without hormone replacement therapy (HRT). MATERIALS AND METHODS: All protocols were approved by the internal review board, and signed informed consent was obtained from all participants. Forty-five healthy volunteers underwent imaging by using T2-weighted and DTI MR sequences at 3 T. Premenopausal volunteers (n = 16) underwent imaging weekly, four times during one menstrual cycle. Postmenopausal volunteers (n = 19) and lactating volunteers (n = 10) underwent imaging once. The principal diffusion coefficients (λ1, λ2, and λ3), apparent diffusion coefficient (ADC), fractional anisotropy (FA), and maximal anisotropy (λ1-λ3) were calculated pixel by pixel for the fibroglandular tissue in the entire breast. RESULTS: In all premenopausal volunteers, the DTI parameters exhibited high repeatability, remaining almost equal along the menstrual cycle, with a low mean within-subject coefficient of variance of λ1, λ2, λ3, and ADC (1%-2% for all) and FA (5%), as well as a high intraclass correlation of 0.92-0.98. The diffusion coefficients were significantly lower (a) in the group without HRT use as compared with the group with HRT use (P < .01) and premenopausal volunteers (P < .01) and (b) in the lactating volunteers as compared with the premenopausal volunteers (P < .005). No significant differences in DTI parameters were found between premenopausal volunteers free of oral contraceptives and those who used oral contraceptives (P = .28-0.82) and between premenopausal volunteers and postmenopausal volunteers who used HRT (P = .31-0.93). CONCLUSION: DTI parameters are not sensitive to menstrual cycle changes, while menopause, long-term HRT, and presence of milk in lactating women affected the DTI parameters. Therefore, the timing for performing breast DTI is not restricted throughout the menstrual cycle, whereas the modulations in diffusion parameters due to HRT and lactation should be taken into account in DTI evaluation.

A novel functional infrared imaging system coupled with multiparametric computerised analysis for risk assessment of breast cancer.

OBJECTIVE: We evaluated a functional three-dimensional (3D) infrared imaging system (3DIRI) coupled with multiparametric computer analysis for risk assessment of breast cancer. The technique provides objective risk assessment for the presence of a malignant tumour based on automated parameters derived from a clinically known training set. METHODS: Following institutional review board approval, we recruited 434 women for this prospective multicentre trial, including 256 healthy woman undergoing routine screening mammography with BI-RADS-1 results and 178 women with newly diagnosed breast cancer. This was a two-phase study: an initial training and calibration phase, followed by a two-armed blinded evaluation phase (52 healthy and 66 with breast cancer). 3DIRI data sets were acquired using a non-contact, no radiation system. RESULTS: The sensitivity and specificity of functional infrared imaging in providing the correct risk for the presence of breast cancer were 90.9 % and 72.5 %, respectively. The area under the ROC curve was 86 %. Forty-two of the 60 (70 %) cancers in women correctly classified by the system as suspicious were smaller than 20 mm in size. CONCLUSION: The preliminary blinded results of this novel technology show sufficient performance of functional infrared imaging in providing risk assessment for breast cancer to warrant further clinical studies. KEY POINTS: • 3D functional infrared imaging (3DIRI) provides new metabolic signatures from breast lesions. • 3DIRI offers high sensitivity for risk assessment of breast cancer. • It also has reasonable specificity. • This initial experience warrants further evaluation in larger clinical trials.

Parametric diffusion tensor imaging of the breast.

OBJECTIVES: To investigate the ability of parametric diffusion tensor imaging (DTI), applied at 3 Tesla, to dissect breast tissue architecture and evaluate breast lesions. MATERIALS AND METHODS: All protocols were approved and a signed informed consent was obtained from all subjects. The study included 21 healthy women, 26 women with 33 malignant lesions, and 14 women with 20 benign lesions. Images were recorded at 3 Tesla with a protocol optimized for breast DTI at a spatial resolution of 1.9 × 1.9 × (2-2.5) mm3. Image processing algorithms and software, applied at pixel resolution, yielded vector maps of prime diffusion direction and parametric maps of the 3 orthogonal diffusion coefficients and of the fractional anisotropy and maximal anisotropy. RESULTS: The DTI-derived vector maps and parametric maps revealed the architecture of the entire mammary fibroglandular tissue and allowed a reliable detection of malignant lesions. Cancer lesions exhibited significantly lower values of the orthogonal diffusion coefficients, λ1, λ2, λ3, and of the maximal anisotropy index λ1-λ3 as compared with normal breast tissue (P < 0.0001) and to benign breast lesions (P < 0.0009 and 0.004, respectively). Maps of λ1 exhibited the highest contrast-to-noise ratio enabling delineation of the cancer lesions. These maps also provided high sensitivity/specificity of 95.6%/97.7% for differentiating cancers from benign lesions, which were similar to the sensitivity/specificity of dynamic contrast-enhanced magnetic resonance imaging of 94.8%/92.9%. Maps of λ1-λ3 provided a secondary independent diagnostic parameter with high sensitivity of 92.3%, but low specificity of 69.5% for differentiating cancers from benign lesions. CONCLUSION: Mapping the diffusion tensor parameters at high spatial resolution provides a potential novel means for dissecting breast architecture. Parametric maps of λ1 and λ1-λ3 facilitate the detection and diagnosis of breast cancer.

Incisional endometriomas: CT findings.

We report a woman with two painful abdominal-wall masses within the scar of a previous cesarian section. The CT findings and the differential diagnosis are presented.

Isolated severe renal injuries after minimal blunt trauma to the upper abdomen and flank: CT findings.

Renal injuries caused by blunt abdominal trauma are common in children. Serious renal trauma is associated with insult to other organs, whereas isolated renal injuries are usually minor. We present the cases of six male children (aged 7-17 years) with major isolated renal injuries due to minimal blunt trauma to the upper adbomen and/or the flank, out of a total of 21 children admitted with renal trauma in a 5-years period. On physical examination all patients had a painful, tender abdomen and/or flank with ipsilateral bruises and ecchymosis. Hematuria, either macro ( n=4) or micro ( n=2), was found in all. The injuries were left-sided in five and were of a variable severity (grade III: n=2; grade IV: n=3; grade V: n=1 according to the kidney injury scale of the American Association for the Surgery of Trauma). Four children underwent nephrectomy. This small series underlines that major kidney insult can occur after a minimal blunt trauma localized to the flank or upper abdomen. Abdominal CT should be performed when clinical or laboratory findings or the mechanism of trauma suggest renal injury.

CT findings in patients with small bowel obstruction due to phytobezoar.

The role of CT in evaluating patients with small bowel obstruction (SBO) has been extensively described in the current literature. We present the CT findings of SBO due to a phytobezoar, afterwards surgically confirmed, in 5 men and 1 woman (aged 32-89 years) out of 95 patients diagnosed by CT as having SBO in a 44-month period. These six patients underwent abdominal CT prior to operation and the CT findings were retrospectively reviewed. All six patients presented with clinical symptoms and signs of SBO; three of them had undergone gastric surgery 13, 17, and 22 years earlier, respectively. In all six cases, CT showed an ovoid intraluminal mass, 3 x 5 cm in size and of a mottled appearance, at the transition zone between dilated and collapsed small bowel loops. This was in contrast to feces-like material (the "small bowel feces sign"), seen within dilated small bowel loops in nine patients with SBO, and was typically longer. As CT is frequently performed for suspected SBO, an ovoid, short intraluminal mottled mass seen at the site of an obstruction may be regarded as a pathognomonic preoperative sign of an obstructing phytobezoar.

Computed tomographic features of intraperitoneal fat-containing lesions: pictorial essay.

Abdominal CT, which is a common imaging modality performed for a variety of clinical indications, provides an important tool in the diagnosis and evaluation of various lesions with fatty components affecting the peritoneal cavity and its contents.

Fasting hypoglycemia in solitary fibrous tumor of the peritoneum: a diagnostic clue for an emergent situation.

Solitary fibrous tumors are rare fibrous tumors found in various anatomic sites. Extrathoracic neoplasms are often symptomatic at presentation, with paraneoplastic hypoglycemia being reported as one of the associated clinical features of such slow-growing tumors. As hypoglycemia can be an emergent clinical situation, we describe a patient with a giant abdominal tumor who presented with a symptomatic hypoglycemia, which might be regarded as a diagnostic clue.

Acute epiploic appendagitis: CT findings in 33 cases.

Acute epiploic appendagitis (AEA) is a benign self-limiting process presenting with acute abdominal pain often misdiagnosed clinically as either diverticulitis or appendicitis, but which has a pathognomonic CT appearance. The CT findings in 33 adult patients diagnosed by CT over a 33-month period as having AEA were retrospectively reviewed. The study group included 24 men and 9 women, with a mean age of 44.6 years. The mean age of the male patients was lower than that of the female patients, 40.9 vs 54.7 years. All patients presented with acute abdominal pain, mainly in the left ( n=21) and right ( n=9) lower quadrants, with localized tenderness in all patients and peritoneal irritation in 15 of them. Low-grade fever was found in 8 patients and mild leukocytosis in 16. Characteristic CT findings of an oval fatty mass with central streaky densities and surrounded by mesenteric stranding adjacent to the serosal surface of the colon were seen in all cases. Additional findings included mural thickening of the juxtaposed colon in 16 patients and peritoneal fluid in 7. One patient underwent surgery on the basis of an erroneous diagnosis of acute appendicitis. As CT is often used nowadays to evaluate various acute abdominal complaints, it may be the first imaging modality by which AEA is diagnosed. AEA should be included in the differential diagnosis in young male patients with localized left lower abdominal pain and tenderness.