Using PET to Characterize Equivocal Brain MRI Findings in a Patient With Treated High-Grade Glioma.

Addition of CT to Improve the Diagnostic Confidence for the Detection of Sacroiliac Joint Erosions in Patients with Equivocal MRI Findings.

<div>AbstractPurpose:<p>The CeTeG/NOA-09 phase III trial demonstrated a significant survival benefit of lomustine–temozolomide chemoradiation in patients with newly diagnosed glioblastoma with methylated O<sup>6</sup>-methylguanine-DNA methyltransferase (MGMT) promoter. Following lomustine–temozolomide chemoradiation, late and prolonged pseudoprogression may occur. We here evaluated the value of amino acid PET using O-(2-[<sup>18</sup>F]fluoroethyl)-l-tyrosine (FET) for differentiating pseudoprogression from tumor progression.</p>Experimental Design:<p>We retrospectively identified patients (i) who were treated off-study according to the CeTeG/NOA-09 protocol, (ii) had equivocal MRI findings after radiotherapy, and (iii) underwent additional FET-PET imaging for diagnostic evaluation (number of scans, 1–3). Maximum and mean tumor-to-brain ratios (TBR<sub>max</sub>, TBR<sub>mean</sub>) and dynamic FET uptake parameters (e.g., time-to-peak) were calculated. In patients with more than one FET-PET scan, relative changes of TBR values were evaluated, that is, an increase or decrease of >10% compared with the reference scan was considered as tumor progression or pseudoprogression. Diagnostic performances were evaluated using ROC curve analyses and Fisher exact test. Diagnoses were confirmed histologically or clinicoradiologically.</p>Results:<p>We identified 23 patients with 32 FET-PET scans. Within 5–25 weeks after radiotherapy (median time, 9 weeks), pseudoprogression occurred in 11 patients (48%). The parameter TBR<sub>mean</sub> calculated from the FET-PET performed 10 ± 7 days after the equivocal MRI showed the highest accuracy (87%) to identify pseudoprogression (threshold, <1.95; <i>P</i> = 0.029). The integration of relative changes of TBR<sub>mean</sub> further improved the accuracy (91%; <i>P</i> < 0.001). Moreover, the combination of static and dynamic parameters increased the specificity to 100% (<i>P</i> = 0.005).</p>Conclusions:<p>The data suggest that FET-PET parameters are of significant clinical value to diagnose pseudoprogression related to lomustine–temozolomide chemoradiation.</p></div>

The CeTeG/NOA-09 phase III trial demonstrated a significant survival benefit of lomustine-temozolomide chemoradiation in patients with newly diagnosed glioblastoma with methylated O6-methylguanine-DNA methyltransferase (MGMT) promoter. Following lomustine-temozolomide chemoradiation, late and prolonged pseudoprogression may occur. We here evaluated the value of amino acid PET using O-(2-[18F]fluoroethyl)-l-tyrosine (FET) for differentiating pseudoprogression from tumor progression. We retrospectively identified patients (i) who were treated off-study according to the CeTeG/NOA-09 protocol, (ii) had equivocal MRI findings after radiotherapy, and (iii) underwent additional FET-PET imaging for diagnostic evaluation (number of scans, 1-3). Maximum and mean tumor-to-brain ratios (TBRmax, TBRmean) and dynamic FET uptake parameters (e.g., time-to-peak) were calculated. In patients with more than one FET-PET scan, relative changes of TBR values were evaluated, that is, an increase or decrease of >10% compared with the reference scan was considered as tumor progression or pseudoprogression. Diagnostic performances were evaluated using ROC curve analyses and Fisher exact test. Diagnoses were confirmed histologically or clinicoradiologically. We identified 23 patients with 32 FET-PET scans. Within 5-25 weeks after radiotherapy (median time, 9 weeks), pseudoprogression occurred in 11 patients (48%). The parameter TBRmean calculated from the FET-PET performed 10 ± 7 days after the equivocal MRI showed the highest accuracy (87%) to identify pseudoprogression (threshold, <1.95; P = 0.029). The integration of relative changes of TBRmean further improved the accuracy (91%; P < 0.001). Moreover, the combination of static and dynamic parameters increased the specificity to 100% (P = 0.005). The data suggest that FET-PET parameters are of significant clinical value to diagnose pseudoprogression related to lomustine-temozolomide chemoradiation.

&lt;div&gt;AbstractPurpose:&lt;p&gt;The CeTeG/NOA-09 phase III trial demonstrated a significant survival benefit of lomustine–temozolomide chemoradiation in patients with newly diagnosed glioblastoma with methylated O&lt;sup&gt;6&lt;/sup&gt;-methylguanine-DNA methyltransferase (MGMT) promoter. Following lomustine–temozolomide chemoradiation, late and prolonged pseudoprogression may occur. We here evaluated the value of amino acid PET using O-(2-[&lt;sup&gt;18&lt;/sup&gt;F]fluoroethyl)-l-tyrosine (FET) for differentiating pseudoprogression from tumor progression.&lt;/p&gt;Experimental Design:&lt;p&gt;We retrospectively identified patients (i) who were treated off-study according to the CeTeG/NOA-09 protocol, (ii) had equivocal MRI findings after radiotherapy, and (iii) underwent additional FET-PET imaging for diagnostic evaluation (number of scans, 1–3). Maximum and mean tumor-to-brain ratios (TBR&lt;sub&gt;max&lt;/sub&gt;, TBR&lt;sub&gt;mean&lt;/sub&gt;) and dynamic FET uptake parameters (e.g., time-to-peak) were calculated. In patients with more than one FET-PET scan, relative changes of TBR values were evaluated, that is, an increase or decrease of &gt;10% compared with the reference scan was considered as tumor progression or pseudoprogression. Diagnostic performances were evaluated using ROC curve analyses and Fisher exact test. Diagnoses were confirmed histologically or clinicoradiologically.&lt;/p&gt;Results:&lt;p&gt;We identified 23 patients with 32 FET-PET scans. Within 5–25 weeks after radiotherapy (median time, 9 weeks), pseudoprogression occurred in 11 patients (48%). The parameter TBR&lt;sub&gt;mean&lt;/sub&gt; calculated from the FET-PET performed 10 ± 7 days after the equivocal MRI showed the highest accuracy (87%) to identify pseudoprogression (threshold, &lt;1.95; &lt;i&gt;P&lt;/i&gt; = 0.029). The integration of relative changes of TBR&lt;sub&gt;mean&lt;/sub&gt; further improved the accuracy (91%; &lt;i&gt;P&lt;/i&gt; &lt; 0.001). Moreover, the combination of static and dynamic parameters increased the specificity to 100% (&lt;i&gt;P&lt;/i&gt; = 0.005).&lt;/p&gt;Conclusions:&lt;p&gt;The data suggest that FET-PET parameters are of significant clinical value to diagnose pseudoprogression related to lomustine–temozolomide chemoradiation.&lt;/p&gt;&lt;/div&gt;

Purpose: The CeTeG/NOA-09 phase III trial demonstrated a significant survival benefit of lomustine–temozolomide chemoradiation in patients with newly diagnosed glioblastoma with methylated O6-methylguanine-DNA methyltransferase (MGMT) promoter. Following lomustine–temozolomide chemoradiation, late and prolonged pseudoprogression may occur. We here evaluated the value of amino acid PET using O-(2-[18F]fluoroethyl)-l-tyrosine (FET) for differentiating pseudoprogression from tumor progression. Experimental Design: We retrospectively identified patients (i) who were treated off-study according to the CeTeG/NOA-09 protocol, (ii) had equivocal MRI findings after radiotherapy, and (iii) underwent additional FET-PET imaging for diagnostic evaluation (number of scans, 1–3). Maximum and mean tumor-to-brain ratios (TBRmax, TBRmean) and dynamic FET uptake parameters (e.g., time-to-peak) were calculated. In patients with more than one FET-PET scan, relative changes of TBR values were evaluated, that is, an increase or decrease of >10% compared with the reference scan was considered as tumor progression or pseudoprogression. Diagnostic performances were evaluated using ROC curve analyses and Fisher exact test. Diagnoses were confirmed histologically or clinicoradiologically. Results: We identified 23 patients with 32 FET-PET scans. Within 5–25 weeks after radiotherapy (median time, 9 weeks), pseudoprogression occurred in 11 patients (48%). The parameter TBRmean calculated from the FET-PET performed 10 ± 7 days after the equivocal MRI showed the highest accuracy (87%) to identify pseudoprogression (threshold, Conclusions: The data suggest that FET-PET parameters are of significant clinical value to diagnose pseudoprogression related to lomustine–temozolomide chemoradiation.

An immunoconjugate of the whole antibody, B72.3, has been approved by the FDA. It is labeled with indium-111, which allows imaging studies intended for the diagnosis and staging of colorectal and recurrent ovarian carcinoma. The new diagnostic imaging agent (CYT-103), Oncoscint CR/OV, has found particular use in evaluating patients with recurrent carcinoma. The three major indications for the study are: 1) occult disease--unexplained rise in serum tumor markers (e.g. CEA), with negative work-up including CT; 2) known local recurrence (e.g. liver or rectal area)--surgery is planned, but there is a need to rule out other areas of involvement; 3) clarify equivocal CT or MRI finding--to distinguish whether an abnormality is due to recurrent tumor or scar tissue, fibrosis, or unopacified bowel loop. Oncoscint has proven to be more sensitive than CT in the detection of disease in the pelvis and extrahepatic abdomen. CT remains the modality of choice for the detection of liver metastases. The combined sensitivity of the two modalities is 88% on a per-patient basis.

BACKGROUND In the present study, we characterized the long-term metabolic changes of brain metastases irradiated with stereotactic radiosurgery (SRS) by sequential dynamic PET imaging using the radiolabeled amino acid O-(2-[18F]-fluoroethyl)-L-tyrosine (FET). We hypothesized that this approach is of considerable clinical value to diagnose delayed radiation-induced changes. MATERIAL AND METHODS From 2010–2021, we retrospectively identified patients with brain metastases from solid extracranial primary tumors who (i) were treated with SRS with or without concurrent immunotherapy using checkpoint inhibitors, (ii) had equivocal or progressive MRI findings after SRS, and (iii) subsequently underwent at least two additional dynamic FET PET scans during follow-up for long-term evaluation. Mean tumor-to-brain ratios (TBR) and the dynamic FET PET parameter time-to-peak were obtained. Diagnostic performances were calculated using receiver operating characteristic curve analyses. Diagnoses were confirmed histologically or clinicoradiologically. RESULTS We identified 36 patients with 98 FET PET scans (median number, 3; range, 2–6). Concurrent to SRS, 8 patients (22%) were treated with checkpoint inhibitors. Following SRS, suspicious MRI findings occurred after a median time of 11 months (range, 2–64 months). Subsequently, FET PET scans were acquired over a median period of 13 months (range, 5–60 months). The overall median follow-up time was 26 months (range, 8–101 months). Twenty-one patients (58%) had delayed radiation-induced changes. TBRs calculated from the last available FET PET scan showed the highest accuracy (92%) to identify delayed radiation-induced changes (threshold, 1.95; P&amp;lt;0.001). CONCLUSION FET PET has a high diagnostic accuracy for characterizing the long-term changes of irradiated brain metastases.

Introduction: 22-year-old female being followed for idiopathic recurrent pancreatitis with negative genetic testing, HIDA scan, and image findings status post elective cholecystectomy was found to have pancreaticobiliary junction anomaly with pancreatic duct emanating from common bile duct. Case Description: Patient was seen in July 2017 for chronic abdominal pain and idiopathic pancreatitis with negative HIDA scan and equivocal CT and MRI findings. Genetic workup of PRSSI, CFTR, and SPINK were negative. No family history of pancreatitis. No alcohol consumption. EUS done in July 2017 showed hyperechoic material consistent with sludge in the gallbladder along with thickened gall bladder walls. Pancreatic duct had an irregular contour along with parenchymal abnormalities consistent of hyperechoic foci and the pancreatic duct appeared to disappear into the common bile dict. Patient underwent cholecystectomy in December 2017 without much relief. Patient was again seen in May 2018 at which EUS was again performed along with ERCP. ERCP showed a filling defect on the pancreatogram that consisted of a common channel whereby the pancreatic duct emanates from the common bile duct approximately 2 cm proximal to the sphincter of Oddi (figure 1). A biliary sphincterotomy was performed and temporary stent was placed into the common bile duct. This has so far controlled the patients' symptoms. Discussion: Abnormal pancreaticobiliary junction (APBJ) is a rare disorder that has been associated with high incidence of gallbladder cancer especially in Asian population. This congenital disorder causes the junction of biliary and pancreatic duct to be located outside the duodenal wall forming a common channel. Since the junction doesn't involve the duodenal wall, it's functions is not under the influence of sphincter of Oddi causing pancreatic biliary reflux (PBR). This reflux is associated with likely hyperplasia and carcinoma of the biliary system. APBJ is almost always seen in patients with choledochal cyst. There have been studies that have shown acute and chronic pancreatitis in setting of choledochal cyst but to our knowledge pancreatitis without choledochal cyst in a setting of APBJ has not been described. Clinician and researchers should be aware of APBJ with pancreatic duct emanating from common bile duct as a cause of recurrent pancreatitis.1430.tif Figure 1: A filling defect as seen on the pancreatogram that consist of a common channel whereby the pancreatic duct emanates from the common bile duct approximately 2 cm proximal to the sphincter of Oddi.

BACKGROUND Following brachytherapy, the differentiation of radiation-induced changes (e.g., radiation necrosis) from actual tumor progression using MRI is challenging. To overcome this diagnostic uncertainty, we evaluated the diagnostic value of O-(2-[18F]-fluoroethyl)-L-tyrosine (FET) PET in glioma patients treated with brachytherapy. MATERIAL AND METHODS From 2006-2019, we retrospectively identified WHO grade II or III glioma patients (i) treated with brachytherapy using Iodine-125 seeds, (ii) equivocal or progressive MRI findings inside the radiation field, and (iii) additional FET PET imaging for diagnostic evaluation. Static FET PET parameters such as maximum and mean tumor-to-brain ratios (TBR) and dynamic FET PET parameters (i.e., time-to-peak, slope) were obtained. Diagnostic performances were calculated using receiver operating characteristic curve analyses and Fisher’s exact test. Diagnoses were confirmed histologically or clinicoradiologically. RESULTS Following brachytherapy, suspect MRI findings occurred after a median time of 33 months (range, 5-111 months). In 10 of 21 patients (WHO grade II, n=5; WHO grade III, n=16), treatment-related changes were diagnosed. The best diagnostic performance for identification of treatment-related changes was obtained using maximum TBRs (threshold &amp;lt; 3.20;accuracy, 86%; sensitivity, 100%; specificity, 73%; P=0.007). Mean TBRs reached an accuracy of 76% (threshold &amp;lt; 2.05; sensitivity, 89%; specificity, 64%; P=0.010). Dynamic PET parameters did not reach statistically significant results. CONCLUSION Our data suggest that static FET PET parameters add valuable diagnostic information to diagnose radiation-induced changes in glioma patients treated with brachytherapy.

BACKGROUND Following brachytherapy, the differentiation of radiation-induced changes (e.g., radiation necrosis) from actual tumor progression using MRI is challenging. To overcome this diagnostic uncertainty, we evaluated the diagnostic value of O-(2-[18F]-fluoroethyl)-L-tyrosine (FET) PET in glioma patients treated with brachytherapy. MATERIAL AND METHODS From 2006–2019, we retrospectively identified WHO grade II or III glioma patients (i) treated with brachytherapy using Iodine-125 seeds, (ii) equivocal or progressive MRI findings inside the radiation field, and (iii) additional FET PET imaging for diagnostic evaluation. Static FET PET parameters such as maximum and mean tumor-to-brain ratios (TBR) and dynamic FET PET parameters (i.e., time-to-peak, slope) were obtained. Diagnostic performances were calculated using receiver operating characteristic curve analyses and Fisher’s exact test. Diagnoses were confirmed histologically or clinicoradiologically. RESULTS Following brachytherapy, suspect MRI findings occurred after a median time of 33 months (range, 5–111 months). In 10 of 21 patients (WHO grade II, n=5; WHO grade III, n=16), treatment-related changes were diagnosed. The best diagnostic performance for identification of treatment-related changes was obtained using maximum TBRs (threshold &amp;lt;3.20; accuracy, 86%; sensitivity, 100%; specificity, 73%; P=0.007). Mean TBRs reached an accuracy of 76% (threshold &amp;lt;2.05; sensitivity, 89%; specificity, 64%; P=0.010). Dynamic PET parameters did not reach statistically significant results. CONCLUSION Our data suggest that static FET PET parameters add valuable diagnostic information to diagnose radiation-induced changes in glioma patients treated with brachytherapy.

Background and purposeSpinal cord infarction (SCI) is difficult to diagnosis using MRI findings. We aimed to suggest the optimal timing of MRI studies for diagnosing SCI.Materials and methodsThis retrospective study was approved by our institutional review board. The requirement for informed consent was waived. MRI scans of SCI patients diagnosed between January 2015 and August 2019 were enrolled in the SCI group and subdivided according to the interval between symptom onset and time of MRI scan (A, within 6 h; B, 6–12 hours; C, 12–24 hours; D, 24–72 hours; E, 3–7 days). Three radiologists analyzed the T2WI scans and evaluated the confidence level of diagnosing SCI using a five-point Likert scale: 1, certainly not; 2, probably not; 3, equivocal; 4, probably yes; 5, certainly yes. Scores of 4 and 5 were defined as “T2WI-positive SCI” and scores of 1–3 were defined as “T2WI-negative SCI”.ResultsThe SCI group included 58 MRI scans of 34 patients (mean age, 60.6 ± 14.0 years; 18 women). The T2WI positivity rate was 72.4% (42/58). In contrast to the other subgroups, subgroup A included fewer cases of T2WI-positive SCI (1/4, 25%) than T2WI-negative SCI. A confidence score of 5 was the most common in subgroup D (4/27, 14.8%). Among the 12 patients who underwent MRI studies more than twice, confidence scores increased with time.ConclusionIn patients with suspected SCI showing equivocal initial MRI findings, follow-up MRI studies are helpful, especially when performed between 24 and 72 hours after symptom onset.

BACKGROUND In the present study, we characterized the long-term metabolic changes of brain metastases irradiated with stereotactic radiosurgery (SRS) by sequential dynamic PET imaging using the radiolabeled amino acid O-(2-[18F]-fluoroethyl)-L-tyrosine (FET). We hypothesized that this approach is of considerable clinical value to diagnose delayed radiation-induced changes. PATIENTS AND METHODS From 2010-2021, we retrospectively identified patients with brain metastases from solid extracranial primary tumors who (i) were treated with SRS with or without concurrent immunotherapy using checkpoint inhibitors, (ii) had equivocal or progressive MRI findings after SRS, and (iii) subsequently underwent at least two additional dynamic FET PET scans during follow-up for long-term evaluation. Mean tumor-to-brain ratios (TBR) and the dynamic FET PET parameter time-to-peak were obtained. Diagnostic performances were calculated using receiver operating characteristic curve analyses. Diagnoses were confirmed histologically or clinicoradiologically. RESULTS We identified 36 patients with 98 FET PET scans (median number, 3; range, 2-6). Concurrent to SRS, 8 patients (22%) were treated with checkpoint inhibitors. Following SRS, suspicious MRI findings occurred after a median time of 11 months (range, 2-64 months). Subsequently, FET PET scans were acquired over a median period of 13 months (range, 5-60 months). The overall median follow-up time was 26 months (range, 8-101 months). Twenty-one patients (58%) had delayed radiation-induced changes. TBRs calculated from the last available FET PET scan showed the highest accuracy (92%) to identify delayed radiation-induced changes (threshold, 1.95; P&amp;lt; 0.001). CONCLUSIONS FET PET has a high diagnostic accuracy for characterizing the long-term changes of irradiated brain metastases.

Contrast-enhanced ultrasound in the diagnosis of infiltrative hepatocellular carcinoma: A report of three cases.

Purpose:We evaluated the utility of arterial spin labeling (ASL) imaging of tumor blood flow (TBF) for grading non-enhancing astrocytic tumors.Materials and Methods:Thirteen non-enhancing astrocytomas were divided into high-grade (n = 7) and low-grade (n = 6) groups. Both ASL and conventional sequences were acquired using the same magnetic resonance machine. Intratumoral absolute maximum TBF (TBFmax), absolute mean TBF (TBFmean), and corresponding values normalized to cerebral blood flow (TBFmax and TBFmean ratios) were measured. The Mann-Whitney U test and receiver operating characteristic (ROC) curve analysis were used to assess the accuracy of TBF variables for tumor grading.Results:Compared with low-grade astrocytoma, high-grade astrocytoma exhibited significantly greater absolute TBFmax (90.93 ± 24.96 vs 46.94 ± 20.97 ml/100 g/min, P < 0.001), TBFmean (58.75 ± 19.89 vs 31.16 ± 17.63 ml/100 g/min, P < 0.001), TBFmax ratio (3.34 ± 1.22 vs 1.35 ± 0.5, P < 0.001), and TBFmean ratio (2.15 ± 0.94 vs 0.88 ± 0.41, P < 0.001). The TBFmax ratio yielded the highest diagnostic accuracy (sensitivity 100%, specificity 86.3%), while absolute TBFmean yielded the lowest accuracy (sensitivity 85.7%, specificity 70.1%) by ROC analysis.Conclusion:Parameters from ASL perfusion imaging, particularly TBFmax ratio, may be useful for distinguishing high-grade from low-grade astrocytoma in cases with equivocal conventional MRI findings.

A clinically evident radiculopathy without correlation in the imaging studies represents a serious problem regarding the indication, planning and execution of an operative procedure for its treatment. Both the diagnosis and treatment of such cases are deemed to be difficult without clear morphological correlation. Moreover, the surgeon lacks an important basis for the adequate planning and above all the justification of surgical treatment. Although discography with post-discographic computer tomography (CT discography) is still controversially discussed as an invasive diagnostic measure, the literature shows that this method is not only useful but also indispensable in certain cases. Based on these findings and our own empirical data, we recommend CT discography to be considered for imaging in patients suffering from lumbar radiculopathy with equivocal or insufficient MRI findings. The technique allows an accurate diagnosis and precise planning of a targeted surgical intervention such as endoscopic sequestrotomy or decompression.