Increased Contrast Enhancement Research Articles

Surgical management of unilateral restrictive strabismus in an 8-month-old dog

ABSTRACT Case history An 8-month-old male, entire, mixed-breed dog was presented with a 1-month history of left exophthalmos and green mucopurulent ocular discharge. Subsequently, exophthalmos resolved but esotropia (medial strabismus) developed in the left eye, prompting referral to an ophthalmologist. Clinical findings At the initial referral consultation, enophthalmos and esotropia of the left eye were identified. The patient showed mild improvement after a 3-week tapering course of oral prednisolone and doxycycline. MRI was performed and showed left medial rectus muscle atrophy with increased contrast enhancement which was consistent with chronic extraocular muscle myositis (EOM). A forced duction test was performed to confirm the diagnosis of fibrosing esotropia, which is likely a sequela of chronic EOM. Diagnosis Fibrosing esotropia presumably caused by untreated EOM. Treatment and outcome One month later, esotropia progressed to a marked ventro-medial strabismus resulting in visual deprivation. Surgical release of the ventral oblique, medial and ventral recti muscles was performed, resulting in immediate resolution of the enophthalmos. Despite a tapering post-operative course of oral prednisolone, mild esotropia was present 4 weeks later. In an effort to stabilise the globe position, the low dose of prednisolone was increased to a higher anti-inflammatory dose before slowly tapering over 2 months. The vision in the left eye was improved after surgery and has been maintained since without further treatment. Clinical relevance This is the first documented case of fibrosing esotropia in a young dog with prior signs of acute exophthalmos. Fibrosing esotropia has been documented in certain breeds or as a sequela to chronic EOM. In this patient, it was presumably caused by EOM, which was strongly supported by the case history, progression and MRI findings. Most historical reports of EOM described it as a bilateral condition that resolves with systemic corticosteroids at an anti-inflammatory dose. EOM has been shown to also present unilaterally and it can progress to strabismus if not promptly recognised and treated with systemic steroids. Surgical management can restore vision when severe strabismus results in visual deprivation.

AN UNUSUAL “BLACKBERRY SHAPED” MASS OF DUBIOUS INTERPRETATION (OUT OR IN THE JUGULAR VEIN?) IN A PATIENT WITH METASTATIC MELANOMA. A SPECIAL IMAGING CLINICAL CASE

Abstract A 43 y–o woman, without cardiovascular risk factors, was diagnosed with BRAF+ IIIC melanoma of unknown origin with bilateral axillary lymph node metastases. She started a combined treatment with vemurafenib, cobimetinib (braf/mek inhibitors) and atezolizumab (PDL1 inhibitor) as neoadjuvant therapy, followed after 6 weeks by surgical treatment (that showed pathological complete response) and adjuvant immunotherapy with atezolizumab hitherto ongoing. A serial CT–scan revealed a 0.9x1.3 cm mass (Fig.1) close to the right jugular vein (RJV) with increased contrast enhancement susceptible of vessel ectasia by the radiologist who expressed uncertainty about its site (intra or extravascular?) and asked for further imaging assessment. Therefore, a duplex ultrasound (DU) was performed with the detection of a 0.6x1.2 cm endovascular mobile “blackberry shaped” mass in the RJV and the indication for a vascular surgery evaluation. The patient started enoxaparin 1 mg/Kgx2/die s.c. according to “ex iuvantibus therapy”. However, the vascular surgeon diagnosis confirmed the undetermined site of the mass. The patient decided for a second DU opinion and reached our Cancer Angiology Lab, where a novel DU detected a deep vein thrombosis (DVT) of the RJV (Fig.2–Fig.3). Enoxaparin was replaced with edoxaban 60 mg 1 cp/die since the patient preferred a more manageable root of administration for the requested long–term anticoagulant treatment. After 2 months a DU follow up showed no regression of the mass. Accordingly, the patient proceeded with edoxaban 60 mg/die without any side effects, whereas still in treatment with immunotherapy. Conclusions Thromboembolism is the second leading cause of death in malignancy. Overall, biomarkers and thrombotic risk factors related to patient, tumor and anticancer regimens favor the development of cancer associated thrombosis. Delay in DVT diagnosis and, mostly, in the initiation of a full and long–term anticoagulant treatment, like in this case, enables a chronic evolution of the clot which makes its timely regression more challenging.

Contrast enhancement early after renal malignancy cryoablation: imaging findings associated with benignity.

Contrast enhancement by MRI done early after cryoablation for renal malignancies may suggest residual tumor (RT). However, we have observed MRI enhancement within 48 h of cryoablation in patients who had no contrast enhancement 6weeks later. Our purpose was to identify features of 48-h contrast enhancement in patients without RT. This single-center retrospective study included consecutive patients who underwent percutaneous cryoablation of renal malignancies in 2013-2020, exhibited cryoablation-zone MRI contrast enhancement 48h later, and had available 6-week MRI scans. Persistent or growing CE at 6weeks vs. 48 h was classified as RT. A washout index was calculated for each 48-h MRI, and its performance for predicting RT was assessed by receiver operating characteristic curve analysis. We included 60 patients with 72 cryoablation procedures and 83 cryoablation zones exhibiting 48-h contrast enhancement; mean age was 66 ± 17years. Clear-cell renal cell carcinoma accounted for 95% of tumors. Of the 83 48-h enhancement zones, RT was observed in eight while 75 were benign. The 48-h enhancement was consistently visible at the arterial phase. Washout was significantly associated with RT (p < 0.001) and gradually increasing contrast enhancement with benignity (p < 0.009). A washout index below - 1.1 predicted RT with 88% sensitivity and 84% specificity. MRI contrast enhancement 48 h after cryoablation of renal malignancies was usually benign. Washout was associated with residual tumor, with a washout index value below - 1.1 exhibiting good performance in predicting residual tumor. These findings may help to guide decisions about repeat cryoablation. Magnetic resonance imaging contrast enhancement 48h after cryoablation of renal malignancies rarely indicates residual tumor, which is characterized by washout with a washout index lower than - 1.1. • Contrast enhancement at the arterial phase of magnetic resonance imaging done 48h after cryoablation of a renal malignancy is usually benign. • Residual tumor manifesting as contrast enhancement at the arterial phase is characterized by subsequent marked washout. • A washout index below - 1.1 has 88% sensitivity and 84% specificity for residual tumor.

Leptomeningeal metastasis from neuroendocrine carcinoma of the cervix: illustrative case.

Leptomeningeal carcinomatosis is a rare feature of metastasis that is characterized by thickening and increased contrast enhancement throughout the meninges of the central nervous system (CNS). Leptomeningeal disease (LMD) can occur as spread from primary CNS tumors or as a manifestation of metastasis to the CNS from primary tumor sites outside the CNS. Leptomeningeal disease is, however, rare in cervical cancer, in which metastasis occurs typically from local invasion. The authors discuss the case of CNS metastasis with LMD from the rare neuroendocrine carcinoma of the cervix (NECC). Cervical cancer infrequently metastasizes to the CNS, but NECC is an aggressive variant with greater metastatic potential. Many of these patients will have previously received pelvic radiation, limiting their candidacy for craniospinal radiation for LMD treatment due to field overlap. This illustrative case documents the first known case of NECC CNS metastasis accompanied by LMD treated with intrathecal chemotherapy. Reported is the first known case of NECC with CNS metastasis accompanied by LMD. The authors highlight the potentially critical role of intrathecal chemotherapy, in addition to radiotherapy, in treating leptomeningeal metastasis from cervical cancer.

Early transmural healing and its predictors assessed by magnetic resonance enterography in patients with Crohn's disease receiving ustekinumab.

Transmural healing (TH) is a potential therapeutic goal of Crohn's disease (CD) and is associated with better clinical outcomes. However, few studies have described early TH and its predictors. We aimed to evaluate early TH and its predictors using magnetic resonance enterography (MRE) in patients with CD receiving ustekinumab (UST). This was a retrospective observational study. Patients with active CD treated with UST and their intestinal segments with bowel wall thickness (BWT) ⩽ 3 mm at baseline were included. Clinical characteristics, laboratory indicators, endoscopic manifestations, and MRE indices were evaluated at baseline and week 26 (W26) of the therapy. The following MRE parameters were assessed: BWT, edema, apparent diffusion coefficient (ADC), Clermont score, Magnetic Resonance Index of Activity score, fat stranding, comb sign, and stricture. TH was defined as BWT ⩽ 3 mm without any signs of inflammation (i.e., ulceration, edema, diffusion-weighted hyperintensity, and increased contrast enhancement) at W26. The study included 37 patients with 106 intestinal segments (including 15 proximal small intestines, 33 terminal ilea, and 58 colons). Clinical features, laboratory indicators, endoscopic results, and MRE parameters at W26 were significantly improved after UST treatment in both patient-based and intestinal segment-based analysis. Seven (18.9%) patients and 26 (24.5%) intestinal segments achieved TH at W26. Baseline BWT [odds ratio (OR) = 0.287, 95% confidence interval (CI), 0.090-0.918, p = 0.035] and ADC (OR = 2.997, 95% CI, 1.009-8.908, p = 0.048) predict TH of patients at W26. Baseline ADC (OR = 2.857, 95% CI, 1.285-6.349, p = 0.010) and presence of stenosis (OR = 0.196, 95% CI, 0.052-0.735, p = 0.016) were associated with TH of segments at W26. Early TH assessed by MRE was observed in nearly one-fifth of patients with CD and intestinal segments after UST treatment for 26 weeks. Baseline MRE indices such as BWT and presence of stenosis might negatively predict TH, while ADC might positively predict early TH.

NIMG-32. POSTPROGRESSION SURVIVAL AND MRI FEATURES AT PROGRESSION IN MGMT-METHYLATED GLIOBLASTOMA FOLLOWING TEMOZOLOMIDE (TMZ) OR CCNU/TMZ THERAPY - AN ANALYSIS OF THE CETEG/NOA-09-TRIAL

Abstract INTRODUCTION In the randomized CeTeG/NOA-09 trial, combined CCNU/TMZ was superior to TMZ therapy regarding overall survival (OS) in newly diagnosed patients with MGMT-methylated glioblastoma. Using modified RANO criteria, however, progression-free survival (PFS) and pseudoprogression rates were similar in both arms. Exploring the hypothesis of undetected pseudoprogressions being accountable for this discrepancy, we analyzed patterns of postprogression survival (PPS) and MRI features at RANO-defined progression. METHODS 86 CeTeG/NOA-09 patients with progression (modified RANO criteria) and MRI evaluable for standardized T1 and FLAIR volumetry at baseline and progression were included. Patients were further subdivided to short PPS (&amp;lt; 24 months) or long PPS (&amp;gt; 24 months) and a PPS/PFS ratio was calculated. RESULTS In the CCNU/TMZ arm, long PPS patients (n=10) tended to a shorter PFS (median 7.3 months) than short PPS patients in the same arm (n=33, 14 months, p=0.089, logrank test) and long PPS patients in the TMZ arm (n=9, 12.7 months, p=0.21). The mean PPS/PFS ratio in the long PPS group was markedly higher in the CCNU/TMZ arm (5.8) compared to the TMZ arm (3.3, p=0.043, Mann-Whitney test). Patients with long PPS of the CCNU/TMZ arm showed a nonsignificant tendency to a stronger volumetric increase in T1 enhancement (mean delta 6184,86 vs. 697.5 mm³) and FLAIR–T1-enhancement (mean delta 42671 vs 16860 mm³) at progression as compared to long PPS patients of the TMZ arm. CONCLUSION Combining a substantially increased PPS/PFS ratio (long OS despite particularly short PFS according to RANO) with indications for increased contrast enhancement and FLAIR volume at progression, the patients with long PPS in the CCNU/TMZ arm appear to differ from those in the TMZ arm. These observations support the hypothesis that this group (~25% of CCNU/TMZ-treated patients) contained patients with pseudoprogression undetected by modified RANO criteria.

Gastrointestinal stromal tumors in the duodenum show increased contrast enhancement compared with those in the stomach on computed tomography.

Duodenal gastrointestinal stromal tumors (D-GISTs) are a rare and relatively small subset of GISTs whose imaging features are not well known. The present study aimed to evaluate the enhancement pattern of D-GISTs compared with that of gastric GISTs (G-GISTs) using dynamic computed tomography. This single-center, retrospective, clinicopathological analysis was conducted on 10 patients with D-GISTs who underwent surgery between June 2006 and October 2018. In the same period, 25 patients with G-GISTs underwent surgery and were enrolled. The contrast ratio was defined as the ratio between Hounsfield units in contrast enhanced and unenhanced images in different phases, and these ratios were compared between the D-GIST and G-GIST groups. Furthermore, microvessel density, analyzed by immunohistochemical staining for CD31, was compared between the D-GIST and G-GIST groups. The contrast ratio of D-GIST was significantly higher than that of G-GIST in the arterial, portal and delayed phases (P<0.01, P<0.01 and P=0.02, respectively). The microvessel density of the D-GISTs was significantly higher than that of the G-GISTs (P<0.0001). D-GISTs were more hypervascular than G-GISTs on both imaging and pathological analyses.

Bilateral Optic Neuritis Caused by Meningococcal Meningoencephalitis

AbstractIn this article, we described a case of pathogen-induced bilateral optic neuritis accompanying meningococcal meningoencephalitis in an adolescent male. A 15-year-old boy presented to our emergency room due to progressive severe headache, stiff neck, diffuse extremity pain, fever, and nausea concerning meningoencephalitis. Intravenous ceftriaxone, metamizole, and ondansetron were started immediately. Due to acute autonomic dysregulation and development of petechiae, he was transferred to the pediatric intensive care unit. Next morning, the patient developed severe visual impairment. Investigations revealed elevated C-reactive protein, procalcitonin and leucocyte count, decreased platelet count, and clotting activation. Cerebrospinal fluid (CSF) analysis revealed increased leucocyte count, protein, and decreased glucose concentration with pathological CSF cytology. Brain magnetic resonance imaging revealed an increased contrast enhancement in the optic nerve sheath, consistent with acute bilateral optic neuritis. He was started on high-dose intravenous pulse methylprednisolone therapy. After treatment with ceftriaxone und pulse steroids, the patient was discharged in good condition without any visual sequel.

Prediction of Malignant Transformation of WHO II Astrocytoma Using Mathematical Models Incorporating Apparent Diffusion Coefficient and Contrast Enhancement.

Using only increasing contrast enhancement as a marker of malignant transformation (MT) in gliomas has low specificity and may affect interpretation of clinical outcomes. Therefore we developed a mathematical model to predict MT of low-grade gliomas (LGGs) by considering areas of reduced apparent diffusion coefficient (ADC) with increased contrast enhancement. Patients with contrast-enhancing LGGs who had contemporaneous ADC and histopathology were retrospectively analyzed. Multiple clinical factors and imaging factors (contrast-enhancement size, whole-tumor size, and ADC) were assessed for association with MT. Patients were split into training and validation groups for the development of a predictive model using logistic regression which was assessed with receiver operating characteristic analysis. Among 132 patients, (median age 46.5 years), 106 patients (64 MT) were assigned to the training group and 26 (20 MT) to the validation group. The predictive model comprised age (P = 0.110), radiotherapy (P = 0.168), contrast-enhancement size (P = 0.015), and ADC (P < 0.001). The predictive model (area-under-the-curve [AUC] 0.87) outperformed ADC (AUC 0.85) and contrast-enhancement size (AUC 0.67). The model had an accuracy of 84% for the training group and 85% respectively for the validation group. Our model incorporating ADC and contrast-enhancement size predicted MT in contrast-enhancing LGGs.

Preoperative findings on non-specific CT in patients with primary acute intestinal ischemia: a case-control study.

Primary acute intestinal ischaemia (AII) is an abdominal catastrophe caused by intravascular obstruction of blood supply. It is difficult to diagnose. Computerized tomography (CT) scan is the modality of choice for diagnostic evaluation. Majority of previous studies have evaluated CT findings in patients where AII was suspected. However, unveiling the unique radiological findings also in not initially suspected AII patients, might lead to the timely management of AII patients, and is the aim of this study. In a single-center, retrospective case-control study, preoperative radiological findings from abdominal CT scans in 48 patients with primary AII were compared with 80 non-ischemic controls. Radiological findings were analyzed using multivariable logistical regression with adjustment for age and gender and reported as odds ratios (OR) with 95% confidence intervals (CI) and p values. Thirty-nine (81%) cases with AII were referred to an abdominal CT scan without a specific clinical suspicion of AII. Three main radiological categories (intestinal wall pathology [OR 7.4, CI 2.3-24.0, p value < 0.001], gastrointestinal vessel pathology [OR 19.3, CI 4.6-80.5, p value < 0.001) and intestinal diameter [OR 4.7, CI 1.6-13.4, p value 0.004]) were significantly different in AII patients. Subgroup analysis implied that pneumatosis intestinalis, increased contrast enhancement in the bowel wall, inferior mesenteric artery arteriosclerosis and colonic contraction were predictors of AII. Radiological changes within the intestinal wall, luminal diameter and gastrointestinal vessels are independent predictors of AII. Awareness of these radiological findings, therefore, plays a central role in patients with an indistinct clinical picture in early recognition and treatment of a life-threatening AII. NCT04361110 (April 24, 2020), retrospectively registered.

PET measured hypoxia and MRI parameters in re-irradiated head and neck squamous cell carcinomas: findings of a prospective pilot study

Background: Tumor hypoxia measured by dedicated tracers like [ 18F]fluoromisonidazole (FMISO) is a well-established prognostic factor in head and neck squamous cell carcinomas (HNSCC) treated with definitive chemoradiation (CRT). However, prevalence and characteristics of positron emission tomography (PET) measured hypoxia in patients with relapse after previous irradiation is missing. Here we report imaging findings of a prospective pilot study in HNSCC patients treated with re-irradiation. Methods: In 8 patients with recurrent HNSCC, diagnosed at a median of 18 months after initial radiotherapy/CRT, [ 18F]fluorodeoxyglucose (FDG)-PET/CT (n=8) and FMISO-PET/MRI (n=7) or FMISO-PET/CT (n=1) were performed. Static FMISO-PET was performed after 180 min. MRI sequences in PET/MRI included diffusion-weighted imaging with apparent diffusion coefficient (ADC) values and contrast enhanced T1w imaging (StarVIBE). Lesions (primary tumor recurrence, 4; cervical lymph node, 1; both, 3) were delineated on FDG-PET and FMISO-PET data using a background-adapted threshold-based method. SUV max and SUV mean in FDG- and FMISO-PET were derived, as well as maximum tumor-to-muscle ratio (TMR max) and hypoxic volume with 1.6-fold muscle SUV mean (HV 1.6) in FMISO-PET. Intensity of lesional contrast enhancement was rated relative to contralateral normal tissue. Average ADC values were derived from a 2D region of interest in the tumor. Results: In FMISO-PET, median TMR max was 1.7 (range: 1.1-1.8). Median HV 1.6 was 0.05 ml (range: 0-7.3 ml). Only in 2/8 patients, HV 1.6 was ≥1.0 ml. In FDG-PET, median SUV max was 9.3 (range: 5.0-20.1). On contrast enhanced imaging four lesions showed decreased and four lesions increased contrast enhancement compared to non-pathologic reference tissue. Median average ADC was 1,060 ×10 6 mm 2/s (range: 840-1,400 ×10 6 mm 2/s). Conclusions: This pilot study implies that hypoxia detectable by FMISO-PET may not be as prevalent as expected among loco-regional recurrent, HPV negative HNSCC. ADC values were only mildly reduced, and contrast enhancement was variable. The results require confirmation in larger sample sizes.

PET measured hypoxia and MRI parameters in re-irradiated head and neck squamous cell carcinomas: findings of a prospective pilot study

Background: Tumor hypoxia measured by dedicated tracers like [ 18F]fluoromisonidazole (FMISO) is a well-established prognostic factor in head and neck squamous cell carcinomas (HNSCC) treated with definitive chemoradiation (CRT). However, prevalence and characteristics of positron emission tomography (PET) measured hypoxia in patients with relapse after previous irradiation is missing. Here we report imaging findings of a prospective pilot study in HNSCC patients treated with re-irradiation. Methods: In 8 patients with recurrent HNSCC, diagnosed at a median of 18 months after initial radiotherapy/CRT, [ 18F]fluorodeoxyglucose (FDG)-PET/CT (n=8) and FMISO-PET/MRI (n=7) or FMISO-PET/CT (n=1) were performed. Static FMISO-PET was performed after 180 min. MRI sequences in PET/MRI included diffusion-weighted imaging with apparent diffusion coefficient (ADC) values and contrast enhanced T1w imaging (StarVIBE). Lesions (primary tumor recurrence, 4; cervical lymph node, 1; both, 3) were delineated on FDG-PET and FMISO-PET data using a background-adapted threshold-based method. SUV max and SUV mean in FDG- and FMISO-PET were derived, as well as maximum tumor-to-muscle ratio (TMR max) and hypoxic volume with 1.6-fold muscle SUV mean (HV 1.6) in FMISO-PET. Intensity of lesional contrast enhancement was rated relative to contralateral normal tissue. Average ADC values were derived from a 2D region of interest in the tumor. Results: In FMISO-PET, median TMR max was 1.7 (range: 1.1-1.8). Median HV 1.6 was 0.05 ml (range: 0-7.3 ml). Only in 2/8 patients, HV 1.6 was ≥1.0 ml. In FDG-PET, median SUV max was 9.3 (range: 5.0-20.1). On contrast enhanced imaging four lesions showed decreased and four lesions increased contrast enhancement compared to non-pathologic reference tissue. Median average ADC was 1,060 ×10 6 mm 2/s (range: 840-1,400 ×10 6 mm 2/s). Conclusions: This pilot study implies that hypoxia detectable by FMISO-PET may not be as prevalent as expected among loco-regional recurrent, HPV negative HNSCC. ADC values were only mildly reduced, and contrast enhancement was variable. The results require confirmation in larger sample sizes.

Di- and tri-component spinel ferrite nanocubes: synthesis and their comparative characterization for theranostic applications.

Spinel ferrite nanocubes (NCs), consisting of pure iron oxide or mixed ferrites, are largely acknowledged for their outstanding performance in magnetic hyperthermia treatment (MHT) or magnetic resonance imaging (MRI) applications while their magnetic particle imaging (MPI) properties, particularly for this peculiar shape different from the conventional spherical nanoparticles (NPs), are relatively less investigated. In this work, we report on a non-hydrolytic synthesis approach to prepare mixed transition metal ferrite NCs. A series of NCs of mixed zinc-cobalt-ferrite were prepared and their magnetic theranostic properties were compared to those of cobalt ferrite or zinc ferrite NCs of similar sizes. For each of the nanomaterials, the synthesis parameters were adjusted to obtain NCs in the size range from 8 up to 15 nm. The chemical and structural nature of the different NCs was correlated to their magnetic properties. In particular, to evaluate magnetic losses, we compared the data obtained from calorimetric measurements to the data measured by dynamic magnetic hysteresis obtained under alternating magnetic field (AMF) excitation. Cobalt-ferrite and zinc-cobalt ferrite NCs showed high specific adsorption rate (SAR) values in aqueous solutions but their heating ability was drastically suppressed once in viscous media even for NCs as small as 12 nm. On the other hand, non-stoichiometric zinc-ferrite NCs showed significant but lower SAR values than the other ferrites, but these zinc-ferrite NCs preserved almost unaltered their heating trend in viscous environments. Also, the presence of zinc in the crystal lattice of zinc–cobalt ferrite NCs showed increased contrast enhancement for MRI with the highest T2 relaxation time and in the MPI signal with the best point spread function and signal-to-noise ratio in comparison to the analogue cobalt-ferrite NC. Among the different compositions investigated, non-stoichiometric zinc-ferrite NCs can be considered the most promising material as a multifunctional theranostic platform for MHT, MPI and MRI regardless of the media viscosity in which they will be applied, while ensuring the best biocompatibility with respect to the cobalt ferrite NCs.

PET measured hypoxia and MRI parameters in re-irradiated head and neck squamous cell carcinomas: findings of a prospective pilot study.

Background: Tumor hypoxia measured by dedicated tracers like [ 18F]fluoromisonidazole (FMISO) is a well-established prognostic factor in head and neck squamous cell carcinomas (HNSCC) treated with definitive chemoradiation (CRT). However, prevalence and characteristics of positron emission tomography (PET) measured hypoxia in patients with relapse after previous irradiation is missing. Here we report imaging findings of a prospective pilot study in HNSCC patients treated with re-irradiation. Methods: In 8 patients with recurrent HNSCC, diagnosed at a median of 18 months after initial radiotherapy/CRT, [ 18F]fluorodeoxyglucose (FDG)-PET/CT (n=8) and FMISO-PET/MRI (n=7) or FMISO-PET/CT (n=1) were performed. Static FMISO-PET was performed after 180 min. MRI sequences in PET/MRI included diffusion-weighted imaging with apparent diffusion coefficient (ADC) values and contrast enhanced T1w imaging (StarVIBE). Lesions (primary tumor recurrence, 4; cervical lymph node, 1; both, 3) were delineated on FDG-PET and FMISO-PET data using a background-adapted threshold-based method. SUV max and SUV mean in FDG- and FMISO-PET were derived, as well as maximum tumor-to-muscle ratio (TMR max) and hypoxic volume with 1.6-fold muscle SUV mean (HV 1.6) in FMISO-PET. Intensity of lesional contrast enhancement was rated relative to contralateral normal tissue. Average ADC values were derived from a 2D region of interest in the tumor. Results: In FMISO-PET, median TMR max was 1.7 (range: 1.1-1.8). Median HV 1.6 was 0.05 ml (range: 0-7.3 ml). Only in 2/8 patients, HV 1.6 was ≥1.0 ml. In FDG-PET, median SUV max was 9.3 (range: 5.0-20.1). On contrast enhanced imaging four lesions showed decreased and four lesions increased contrast enhancement compared to non-pathologic reference tissue. Median average ADC was 1,060 ×10 6 mm 2/s (range: 840-1,400 ×10 6 mm 2/s). Conclusions: This pilot study implies that hypoxia detectable by FMISO-PET may not be as prevalent as expected among loco-regional recurrent HNSCC. ADC values were only mildly reduced, and contrast enhancement was variable. The results require confirmation in larger sample sizes.

MRS as an Aid to Diagnose Malignant Transformation in Low-Grade Gliomas with Increasing Contrast Enhancement.

Increased contrast enhancement has been used as a marker of malignant transformation in low-grade gliomas. This marker has been found to have limited accuracy because many low-grade gliomas with increased contrast enhancement remain grade II. We aimed to investigate whether MR spectroscopy can contribute to the diagnosis of malignant transformation in low-grade gliomas with increased contrast enhancement. Patients with low-grade gliomas who had contemporaneous MR spectroscopy and histopathology for tumor regions with increased contrast enhancement between 2004 and 2015 were retrospectively reviewed. Clinical data collected were sex and age, Karnofsky Performance Scale, histologic subtypes, isocitrate dehydrogenase 1 mutation status, disease duration, adjuvant therapy, and post-radiation therapy duration. Imaging data collected were contrast-enhancement size, whole-tumor size, MR spectroscopy metabolite ratios, and tumor grades of regions with increased contrast enhancement. Diagnostic values of these factors on malignant transformation of low-grade gliomas were statistically analyzed. A total of 86 patients with 96 MR spectroscopy studies were included. Tumor grades associated with increased contrast enhancement were grade II (n = 42), grade III (n = 27), and grade IV (n = 27). On multivariate analysis, the NAA/Cho ratio was the only significant factor (P < .001; OR, 7.1; 95% CI, 3.2-16.1) diagnostic of malignant transformation. With 0.222 as the cutoff value, the sensitivity, specificity, and accuracy of NAA/Cho for diagnosing malignant transformation were 94.4%, 83.3%, and 89.6%, respectively. MR spectroscopy complements conventional MR imaging in the diagnosis of malignant transformation in a subgroup of low-grade gliomas with increased contrast enhancement.

Onset of ulcerative colitis during SARS-CoV-2 infection

A 19-year-old, non-smoker woman with a recent history of fever, nausea, vomiting, bloody diarrhea and loss of taste and smell was admitted to the Tor Vergata Hospital. A nasofaringeal swab resulted positive for SARS-CoV-2. At entry, she had a body temperature of 38 °C, pulse of 110 beats/min, and 99% oxygen saturation. She had severe anemia but no shortness of breath or chest pain. C-reactive protein, platelets, fibrinogen and d-dimer were elevated. A chest and abdominal CT scan showed no pneumonia but increased contrast enhancement in the ileum and colon.

Increased contrast enhancement of the parent vessel of unruptured intracranial aneurysms in 7T MR imaging

BackgroundInflammation of the arterial wall may lead to aneurysm formation. The presence of aneurysm enhancement on high-resolution vessel wall imaging (HR-VWI) is a marker of wall inflammation and instability. We...

Decreased contrast enhancement on high-resolution vessel wall imaging of unruptured intracranial aneurysms in patients taking aspirin.

Inflammation plays an integral role in the formation, growth, and progression to rupture of unruptured intracranial aneurysms (UIAs). Animal and human studies have suggested that, due to its antiinflammatory effect, aspirin (ASA) may decrease the risks of growth and rupture of UIAs. High-resolution vessel wall imaging (HR-VWI) has emerged as a noninvasive method to assess vessel wall inflammation and UIA instability. To the authors' knowledge, to date no studies have found a significant correlation between patient use of ASA and contrast enhancement of UIAs on HR-VWI. The University of Iowa HR-VWI Project database was analyzed. This database is a compilation of data on patients with UIAs who prospectively underwent HR-VWI on a 3T Siemens MRI scanner. The presence of aneurysmal wall enhancement was objectively defined using the aneurysm-to-pituitary stalk contrast ratio (CRstalk). This ratio was calculated by measuring the maximal signal intensity in the aneurysmal wall and the pituitary stalk on postcontrast T1-weighted images. Data on aneurysm size, morphology, and location and patient demographics and comorbidities were collected. Use of ASA was defined as daily intake of ≥ 81 mg during the previous 6 months or longer. Univariate and multivariate logistic regression analyses were performed to determine factors independently associated with increased contrast enhancement of UIAs on HR-VWI. In total, 74 patients harboring 96 UIAs were included in the study. The mean patient age was 64.7 ± 12.4 years, and 60 patients (81%) were women. Multivariate analysis showed that age (OR 1.12, 95% CI 1.05-1.19), aneurysm size ≥ 7 mm (OR 21.3, 95% CI 4.88-92.8), and location in the anterior communicating, posterior communicating, and basilar arteries (OR 10.7, 95% CI 2.45-46.5) were significantly associated with increased wall enhancement on HR-VWI. On the other hand, use of ASA was significantly associated with decreased aneurysmal wall enhancement on HR-VWI (OR 0.22, 95% CI 0.06-0.83, p = 0.026). The study results establish a correlation between use of ASA daily for ≥ 6 months and significant decreases in wall enhancement of UIAs on HR-VWI. The findings also demonstrate that detection of wall enhancement using HR-MRI may be a valuable noninvasive method for assessing aneurysmal wall inflammation and UIA instability.

Atypical infectious spondylitis with reduced bone marrow enhancement: "black vertebra sign".

A few patients suspected of having infectious spondylitis exhibited a reduced enhancement pattern on postcontrast T1-weighted (T1W) magnetic resonance imaging (MRI). To investigate the characteristics of infectious spondylitis patients who exhibited reduced vertebral enhancement. From January 2010 to November 2017, 456 patients with findings suspicious for infectious spondylitis on 706 postcontrast T1W imaging were retrospectively evaluated. When an affected vertebra exhibited markedly reduced enhancement compared to normal bone marrow (BM), the vertebra was termed a "black vertebra." MRI and computed tomography (CT) imaging findings within two-week intervals and the patients' clinical characteristics were reviewed. Ten patients (5 men, 5 women; mean age 66.4 years) whose MRI scans revealed the black vertebra sign were included. Among the 10 patients with black vertebrae, six patients exhibited signal voids in or around the affected vertebral bodies on T2-weighted (T2W) images. Eight patients showed air bubbles on CT images, suggestive of emphysematous infection. However, the typical image findings of infectious spondylitis were uncommon, namely, low BM signal intensity (SI) on T1W images (n=1) and intradiscal fluid-equivalent SI on T2W images (n=5) at an early stage. On follow-up MRI (average interval 7.2 weeks from initial MRI), available for five patients, marked progression of infection was evidenced by increased numbers of affected segments (n=3), low T1 SIs of the affected vertebrae (n=5), and increased contrast enhancement (n=3). Five patients underwent surgery to treat infections not controlled by antibiotics. A black vertebra sign on postcontrast T1W imaging seems to reflect an early emphysematous infection.

Abstract 48: High-Resolution Vessel Wall Imaging of Cryptogenic Stroke: A 7T MRI Study

Background: High-resolution vessel wall imaging (HR-VWI) has emerged as a useful tool for characterization of intracranial vasculopathic processes. HR-VWI allows better characterization of the arterial wall and may aid in the identification of atherosclerotic plaques, intra-arterial hemorrhages such as in the case of dissections and/or increased contrast enhancement such as in vasculitis. 7T HR-VWI may provide additional information in the identification of stroke mechanism in patients with cryptogenic stroke. Methods: Patients with cryptogenic stroke were prospectively imaged with a 7T scan. Strokes were determined to be cryptogenic after an extensive diagnostic work-up was completed. T1-weighted (pre- and post-contrast), T2-weighted, TOF and SWAN sequences were obtained. Demographic and clinical information was gathered from electronic medical charts. Results: Seventeen patients were included. Mean age was 57.8 ± 16.3 years-old, and 10 (58.8%) were women. HR-VWI determined the etiology of AIS in all subjects: 12 (70.6%) intracranial atherosclerotic disease (ICAD), 3 small-vessel disease and 2 arterial dissections. Inter-observer agreement was κ = 0.92. Plaque enhancement was identified in 14 cases, and intraplaque hemorrhage in 1 case of arterial dissection. In a patient with angiography suggestive of Moyamoya disease, HR-VWI determined the presence of diffuse ICAD as the underlying cause of stroke. Conclusion: HR-VWI may be used in patients with cryptogenic stroke to identify the etiologic mechanism and guide treatment. Figure: Axial-DWI (A) shows an acute right-medullary infarct (arrow). (B) Right-VA stenosis (arrow) on CTA. 7T axial-SWAN (C) reveals focal-susceptibility (arrowhead) and intra-vessel hemosiderin (arrow) suggestive of IPH. Axial-T1 pre-contrast (D), post-contrast (E) and sagittal MPR (F) images show eccentric thickening/enhancement of right-VA (arrowheads), compared to normal-appearing left-VA (arrows D-E).