Spencer C. Behr

Imaging of Müllerian Duct Anomalies

The müllerian ducts are paired embryologic structures that undergo fusion and resorption in utero to give rise to the uterus, fallopian tubes, cervix, and upper two-thirds of the vagina. Interruption of normal development of the müllerian ducts can result in formation of müllerian duct anomalies (MDAs). MDAs are a broad and complex spectrum of abnormalities that are often associated with primary amenorrhea, infertility, obstetric complications, and endometriosis. MDAs are commonly associated with renal and other anomalies; thus, identification of both kidneys is important. However, MDAs are not associated with ovarian anomalies. Hysterosalpingography (HSG) is routinely used in evaluation of infertility. Because a key component of MDA characterization is the external uterine fundal contour, HSG is limited for this purpose. Patients suspected of having an MDA are often initially referred for pelvic ultrasonography (US). Magnetic resonance (MR) imaging is typically reserved for complex or indeterminate cases. MR imaging is the imaging standard of reference because it is noninvasive, does not involve ionizing radiation, has multiplanar capability, allows excellent soft-tissue characterization, and permits a greater field of interrogation than does US. Use of MR imaging for evaluation of MDAs reduces the number of invasive procedures and related costs by guiding management decisions.

Detection of small pulmonary nodules with ultrashort echo time sequences in oncology patients by using a PET/MR system

PURPOSE To investigate the utility of a free-breathing ultrashort echo time (UTE) sequence for the evaluation of small pulmonary nodules in oncology patients by using a hybrid positron emission tomography (PET)/magnetic resonance (MR) imaging system and to compare the nodule detection rate between UTE and a conventional three-dimensional gradient-recalled-echo (GRE) technique. MATERIALS AND METHODS In this HIPAA-compliant, institutional review board-approved prospective study, 82 pulmonary nodules were identified in eight patients with extrathoracic malignancies. Patients underwent free-breathing UTE and dual-echo three-dimensional GRE imaging of the lungs in a hybrid PET/MR imaging unit immediately after clinical PET/computed tomography (CT). CT was considered the reference standard for nodule detection. Two reviewers identified nodules and obtained measurements on MR images. The McNemar test was used to evaluate differences in nodule detection rate between MR techniques, and interrater agreement was assessed by using Bland-Altman plots. RESULTS Mean nodule diameter ± standard deviation was 6.2 mm ± 2.7 (range, 3-17 mm). The detection rate was higher for UTE imaging than for dual-echo GRE imaging for nodules of at least 4 mm (82% vs 34%, respectively; P < .001), with the largest difference in detection noted in the 4-8-mm nodule group (79% vs 21%, P < .001). UTE imaging displayed a higher detection rate than dual-echo GRE imaging for nodules without fluorodeoxyglucose avidity (68% vs 22%, respectively; P < .001). Interrater reliability of nodule detection with MR imaging was high (κ = 0.90 for UTE imaging and κ = 0.92 for dual-echo GRE imaging). CONCLUSION A free-breathing UTE sequence has high sensitivity for the detection of small pulmonary nodules (4-8 mm) and outperformed a three-dimensional dual-echo GRE technique for the detection of small, non-fluorodeoxyglucose-avid nodules.

CT Findings in Adult Celiac Disease

Celiac disease is now recognized as a common disease, occurring in about one in every 200 Americans. However, less than 10% of cases are currently diagnosed, with a diagnostic delay of more than 10 years from onset of symptoms. In the past, barium examination of the small bowel demonstrated a pattern of abnormal findings caused by the pathophysiologic changes induced by malabsorption, thus leading to diagnosis of celiac disease and other diseases of malabsorption. Although not specific, that pattern prompted further patient evaluation. The number of barium examinations performed and the skill necessary to interpret their results are both in decline. Abdominal pain in celiac disease is a common early complaint that often leads to computed tomography (CT). Improved CT resolution now permits better depiction of the small bowel, colon, and mesenteric lymph nodes, all of which are affected by celiac disease. Detection of celiac disease with CT will allow treatment to be initiated to prevent the significant morbidity and increased mortality associated with a delay in diagnosis. The abnormal CT findings seen over the past decade during review of more than 200 cases of celiac disease demonstrate that CT depicts more features of celiac disease than did barium examination. Pattern recognition for the diagnosis of small bowel diseases that create structural changes in the bowel wall is well accepted. Because it demonstrates features of celiac disease not detected with barium examination, CT may be more sensitive than barium examination for diagnosis of this disease.

Triple-Negative and Non–Triple-Negative Invasive Breast Cancer: Association between MR and Fluorine 18 Fluorodeoxyglucose PET Imaging

PURPOSE To assess the relationship between parameters measured on dynamic contrast material-enhanced (DCE) magnetic resonance (MR) imaging and fluorine 18 fluorodeoxyglucose (FDG) positron emission tomography (PET)/computed tomography (CT) in primary invasive breast cancer. MATERIALS AND METHODS This HIPAA-compliant study was a retrospective review of medical records and therefore approved by the institutional review board without the requirement for informed consent. Patients with a diagnosis of invasive breast cancer from January 2005 through December 2009 who underwent both DCE MR imaging and FDG PET/CT before treatment initiation were retrospectively identified. Fractional volumes were measured for ranges of signal enhancement ratio (SER) values from DCE MR imaging data and compared with maximum standardized uptake values (SUVmax) from FDG PET/CT data. Linear regression analysis was performed to clarify the relationship between SER and SUVmax, adjusting for tumor size, pathologic grade, and receptor status. RESULTS Analyzed were 117 invasive breast cancers in 117 patients. Overall, a higher percentage of high washout kinetics was positively associated with SUVmax (1.57% increase in SUVmax per 1% increase in high washout; P = .020), and a higher percentage of low plateau kinetics was negatively associated with SUVmax (1.19% decrease in SUVmax per 1% increase in low plateau; P = .003). These relationships were strongest among triple-negative (TN) tumors (4.34% increase in SUVmax per 1% increase in high washout and 2.65% decrease in SUVmax per 1% increase in low plateau; P = .018 and .004, respectively). CONCLUSION In invasive breast carcinoma, there is a positive relationship between the percentage of high washout and SUVmax and a negative relationship between the percentage of low plateau and SUVmax. These results are stronger in TN tumors. SUPPLEMENTAL MATERIAL http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.13130058/-/DC1.

Intramural Fat in the Duodenum and Proximal Small Intestine in Patients with Celiac Disease

OBJECTIVE The purpose of this article is to describe and illustrate intramural fat in the duodenum and jejunum, to our knowledge a previously undescribed finding in celiac disease. CONCLUSION Celiac disease is known to produce inflammation of the duodenum and jejunum. We propose that postinflammatory intramural fat deposition occurs in a distribution likely unique for celiac disease. CT scans of the chest and abdomen obtained for many indications include these portions of the bowel. Celiac disease is now recognized as a common disease, and the recognition of intramural fat in the duodenum and jejunum on CT may allow earlier diagnosis.

The combination of axitinib followed by paclitaxel/carboplatin yields extended survival in advanced BRAF wild-type melanoma: results of a clinical/correlative prospective phase II clinical trial

Background:Simultaneous chemotherapy with vascular endothelial growth factor (VEGF) inhibition has not shown additional benefit over chemotherapy alone in advanced melanoma. We tested administration of the potent VEGF inhibitor axitinib followed by paclitaxel/carboplatin to determine whether enhanced tumour proliferation during axitinib withdrawal leads to sustained chemosensitivity.Methods:We conducted a prospective phase II trial in metastatic melanoma patients with ECOG performance status 0–1 and normal organ function. Axitinib 5 mg PO b.i.d. was taken on days 1–14 of each 21-day treatment cycle, and carboplatin (AUC=5) with paclitaxel (175 mg m−2) was administered on day 1 starting with cycle 2. 3′-Deoxy-3′-18F-fluorothymidine (18F-FLT)-PET scans were performed in five patients to assess tumour proliferation on days 1, 14, 17, and 20 of cycle 1. Molecular profiling for BRAF was performed for all patients with cutaneous, acral, or mucosal melanoma.Results:The treatment was well tolerated. The most common grade 3 AEs were hypertension, neutropenia, and anaemia. Grade 4 non-haematologic AEs were not observed. Four of five patients completing 18F-FLT-PET scans showed increases (23–92%) in SUV values during the axitinib holiday. Of 36 evaluable patients, there were 8 confirmed PRs by Response Evaluation Criteria in Solid Tumors. Overall, 20 patients had SD and 8 had PD as the best response. The median PFS was 8.7 months and the median overall survival was 14.0 months. Five BRAFV600E/K patients had significantly worse PFS than patients without these mutations.Conclusions:Axitinib followed by carboplatin and paclitaxel was well tolerated and effective in BRAF wild-type metastatic melanoma. 3′-Deoxy-3′-18F-fluorothymidine-PET scans showed increased proliferation during axitinib withdrawal.

Radiological Evaluation of Bowel Ischemia

Intestinal ischemia, which refers to insufficient blood flow to the bowel, is a potentially catastrophic entity that may require emergent intervention or surgery in the acute setting. Although the clinical signs and symptoms of intestinal ischemia are nonspecific, computed tomography (CT) findings can be highly suggestive in the correct clinical setting. In our article, we review the CT diagnosis of arterial, venous, and nonocclusive intestinal ischemia. We discuss the vascular anatomy, pathophysiology of intestinal ischemia, CT techniques for optimal imaging, key and ancillary radiological findings, and differential diagnosis.

Focal Colonic FDG Activity with PET/CT: Guidelines for Recommendation of Colonoscopy.

Focal 18 F-fluorodeoxyglucose (FDG) colonic activity can be incidentally seen in positron emission tomography/computed tomography (PET/CT) scans. Its clinical significance is still unclear. The purpose of this study was to assess the significance of focal FDG activity in PET/CT scans by correlating the imaging findings to colonoscopy results, and come up with some guidelines for recommendation of follow-up colonoscopy. A total of 133 patients who underwent both 18 F-FDG PET/CT for different oncological indications and colonoscopy within 3 months were retrospectively studied. Imaging, colonoscopy and pathology results were analyzed. Of the 133 FDG-PET/CT scans, 109/133 (82%) did not show focal colonic FDG activity, and 24/133 (18%) did. Of the 109/133 PET/CTs without focal colonic FDG activity, 109/109 (100%) did not have evidence of colon cancer after colonoscopy and histology. Of the 24/133 PET/CTs with focal colonic FDG activity, 10/24 (42%) had pathologic confirmation of colon cancer and 14/24 (58%) did not have evidence of colon cancer after colonoscopy and histological analysis. Sensitivity was 10/10 (100%), specificity 109/123 (89%), positive predictive value (PPV) 10/24 (42%) and negative predictive value (NPV) 109/109 (100%). Incidental focal 18 FDG activity in PET/CT imaging shows a high sensitivity, specificity and NPV for malignancy, with a not so high PPV of 42%. Although some people would argue that a 42% chance of malignancy justifies colonoscopy, this maybe is not possible in all cases. However, the high sensitivity of the test does not allow these studies to be overlooked. We provide our recommendations as per when to send patients with focal FDG colonic activity to have further characterization with colonoscopy.

18F Fluorocholine Dynamic Time-of-Flight PET/MR Imaging in Patients with Newly Diagnosed Intermediate- to High-Risk Prostate Cancer: Initial Clinical-Pathologic Comparisons

Purpose To investigate the initial clinical value of fluorine 18 (18F) fluorocholine (FCH) dynamic positron emission tomography (PET)/magnetic resonance (MR) imaging by comparing its parameters with clinical-pathologic findings in patients with newly diagnosed intermediate- to high-risk prostate cancer (PCa) who plan to undergo radical prostatectomy. Materials and Methods The institutional review board approved the study protocol, and informed written consent was obtained from all subjects for this HIPAA-compliant study. Twelve men (mean age ± standard deviation, 61.7 years ± 8.4; range, 46-74 years) with untreated intermediate- to high-risk PCa characterized according to Cancer of the Prostate Risk Assessment (CAPRA) underwent preoperative FCH dynamic PET/MR imaging followed by radical prostatectomy between April and November 2015. PET/MR imaging parameters including average and maximum K1 (delivery rate constant) and standardized uptake values (SUVs) and Prostate Imaging Reporting and Data System (PI-RADS) version 2 scores were measured and compared with clinical-pathologic characteristics. For statistical analysis, the Spearman rank correlation and Mann-Whitney U tests were performed. Results Of the PET parameters, maximum SUV of primary tumors showed significant correlations with several clinical-pathologic parameters including serum prostate-specific antigen level (ρ = 0.71, P = .01), pathologic stage (ρ = 0.59, P = .043), and postsurgical CAPRA score (ρ = 0.72, P = .008). The overall PI-RADS score showed significant correlations with pathologic tumor volume (ρ = 0.81, P < .001), percentage of tumor cells with Gleason scores greater than 3 (ρ = 0.59, P = .02), and postsurgical CAPRA score (ρ = 0.58, P = .046). The high-risk postsurgical CAPRA score patient group had a significantly higher maximum SUV than did the intermediate-risk group. Combined PET and MR imaging showed improved sensitivity (88%) for prediction of pathologic extraprostatic extension compared with that with MR imaging (50%) and PET (75%) performed separately. Conclusion Maximum SUVs and PI-RADS scores from FCH PET/MR imaging show good correlation with clinical-pathologic characteristics, such as postsurgical CAPRA score, which are related to prognosis in patients with newly diagnosed intermediate- to high-risk PCa.

Assessing Biological Response to Bevacizumab Using 18F-Fluoromisonidazole PET/MR Imaging in a Patient with Recurrent Anaplastic Astrocytoma

We present our initial experience in using single modality fluoromisonidazole (FMISO) PET/MR imaging to noninvasively evaluate the biological effects induced by bevacizumab therapy in a patient treated for recurrent high grade glioma. In this index patient, bevacizumab therapy resulted in the development of nonenhancing tumor characterized by reduced diffusion and markedly decreased FMISO uptake in the setting of maintained CBF and CBV. These observations suggest that the dynamic biological interplay between tissue hypoxia and vascular normalization occurring within treated recurrent high grade glioma can be captured utilizing FMISO PET/MR imaging.