Exploration of tumor size measurement methods in preoperative breast cancer assessment using whole-body silicon photomultiplier PET: feasibility and first results.

PURPOSE: Whole-body silicon photomultiplier positron emission tomography (WB SiPM PET) could be used to diagnose breast cancer spread before lumpectomy. We aimed to investigate the method of measuring the tumor size by WB SiPM PET as a basis for diagnosing breast cancer spread in the breast. MATERIALS AND METHODS: We retrospectively reviewed 35 breast cancer lesions in 32 patients who underwent WB SiPM PET/CT in the prone position as preoperative breast cancer examinations from September 2020 to March 2022. In all cases, a 20-mm spherical VOI was placed in the normal mammary gland to measure the mean standardised uptake value (SUVmean) and the standard deviation (SD) of 18F-fluorodeoxyglucose (FDG) uptake. We prepared four types of candidates (SUVmean + 2 SD, SUVmean + 3 SD, 1.5 SUVmean + 2 SD, 1.5 SUVmean + 3 SD) for thresholds for delineating tumor contours on PET images. On the semiautomatic viewer soft, the maximum tumor sizes were measured at each of the four thresholds and compared with the pathological tumor sizes, including the extensive intraductal component (EIC). RESULTS: The lesion detection sensitivity was 97% for WB SiPM PET. PET detected 34 lesions, excluding 4-mm ductal carcinomas in situ (DCIS). PET measurements at the '1.5 SUVmean + 2 SD' threshold demonstrated values closest to the pathological tumor sizes, including EIC. Moreover, '1.5 SUVmean + 2 SD' had the highest concordance (63%). CONCLUSIONS: The study demonstrated that among various PET thresholds, the '1.5 SUVmean + 2 SD' threshold exhibited the best performance. However, even with this threshold, the concordance rate was limited to only 63%.

Liver regeneration after portal vein embolization: comparison between absolute ethanol and N-butyl-cyanoacrylate in an in vivo rat model.

PURPOSE: To compare the effects of absolute ethanol (ethanol) and N-butyl-cyanoacrylate (NBCA) on non-embolized liver lobe regeneration in a rat model. METHODS: Twenty-seven Sprague-Dawley rats underwent portal vein embolization (PVE) using ethanol:lipiodol, 1:1 (ethanol group, n = 11, 40.74%), NBCA:lipiodol, 1:1 (NBCA group, n = 11, 40.74%), or sham treatment (sham group, n = 5, 18.52%). The non-embolized and embolized lobe-to-whole liver weight ratios 14 days after PVE were compared among the groups (n = 5, 18.52%). The expressions of CD68 and Ki-67 and embolized-lobe necrotic area percentages one day after PVE were compared between the ethanol (n = 3, 11.11%) and NBCA (n = 3, 11.11%) groups. RESULTS: The non-embolized lobe-to-whole liver weight ratio after PVE was significantly higher in the NBCA group (n = 5, 33.33%) than in the ethanol group (n = 5, 33.33%) (84.28% ± 1.53% vs. 76.88% ± 4.12%, P = 0.029). The embolized lobe-to-whole liver weight ratio after PVE was significantly lower in the NBCA group than in the ethanol group (15.72% ± 1.53% vs. 23.12% ± 4.12%, P = 0.029). The proportions of CD68- and Ki-67-positive cells in the non-embolized lobe after PVE were significantly higher in the NBCA group (n = 30, 50%) than in the ethanol group (n = 30, 50%) [60 (48-79) vs. 55 (37-70), P = 0.003; 1 (0-2) vs. 1 (0-2), P = 0.004]. The embolized-lobe necrotic area percentage after PVE was significantly larger in the NBCA group (n = 30, 50%) than in the ethanol group (n = 30, 50%) [29.46 (12.56-83.90%) vs. 16.34 (3.22-32.0%), P < 0.001]. CONCLUSION: PVE with NBCA induced a larger necrotic area in the embolized lobe and promoted greater non-embolized liver lobe regeneration compared with PVE with ethanol.

Clinical Experience of Percutaneous Radiofrequency Ablation Using an arfa RF ABLATION SYSTEMⓇ in Various Organs.

Purpose: To evaluate the feasibility, safety, and efficacy of radiofrequency (RF) ablation using an ablation system (arfa RF ABLATION SYSTEMⓇ; Japan Lifeline Co. Ltd.) for treating solid tumors in various organs. Material and Methods: Between October 2019 and August 2021, 80 patients (29 women, 51 men; median age, 70.0 yr) underwent 107 RF ablation sessions using the ablation system to treat 151 tumors in the liver (n = 86), lung (n = 51), adrenal gland (n = 4), pleura (n = 4), bone (n = 3), lymph node (n = 2), and kidney (n = 1). The maximum tumor diameter was 2-40 mm (median, 11 mm). This study evaluated technical success (defined as the completion of planned RF ablation), technique efficacy (defined as the complete tumor ablation on follow-up images), and adverse events. Local tumor progression in 146 curatively treated malignant tumors was evaluated. Results: The technical success rate was 100% (107/107). Ablation zones in two tumors were insufficient. Therefore, the primary technique efficacy rate was 98.1% (105/107). Grade 3 hepatic infarction (1.6%, 1/64) and grade 4 pleuritis (3.4%, 1/29) occurred respectively after liver and lung RF ablation. During the median follow-up period of 10.2 months (Interquartile range, 4.2 and 16.4 months), local tumor progression developed in two tumors (1.4%, 2/146). Conclusions: The arfa RF ABLATION SYSTEMⓇ is a feasible, safe, and effective RF ablation device for managing solid tumors in various organs.

Use of Microballoon Catheter in Transarterial Ethanol Embolization of Renal Angiomyolipoma: A Retrospective Comparative Study with Historical Control?

Purpose: To clarify the utility of microballoon catheter in renal arterial ethanol embolization of renal angiomyolipoma (AML). Material and Methods: A total of 20 patients (15 women, 5 men) with median age of 45 years (39-60 years) underwent embolization to treat 22 AMLs. A mixture of ethanol and iodized oil was injected into the feeding arteries of 13 tumors using balloon occlusion (the balloon embolization group) with a microballoon catheter and 9 tumors without using balloon occlusion (the non-balloon embolization group). Changes in the maximum tumor diameter, tumor volume, and adverse events were evaluated. Result: The median baseline maximum tumor diameters and volumes were 6.3 cm and 61.4 cm3 in the balloon embolization group, and 4.6 cm and 40.1 cm3 in the non-balloon embolization group, respectively. Tumor enhancement disappeared on postembolization angiography in all cases. All tumors shrunk after embolization. There were no statistically significant differences in the percent decrease in the maximum tumor diameter and volume at 10-12 month between balloon occlusion group (31.5% and 67.9%) and control group (34.8% and 62.6%). Fever was significantly more frequent when balloon occlusion was used: 38% vs. 0% (p = 0.03). No major complication was observed in either patient group. Conclusions: Balloon occlusion may not affect tumor shrinkage when embolizing AMLs with a mixture of ethanol and lipiodol.

Coil volume embolization ratio for preventing recanalization after portal vein embolization.

PURPOSE: The purpose of this study was to evaluate the optimum volume embolization ratio (VER) for the prevention of recanalization after portal vein embolization (PVE) and the influence of recanalization on future liver remnant (FLR) function using technetium-99m galactosyl human serum albumin single-photon emission computed tomography (99mTc-GSA SPECT/CT) fusion imaging. METHODS: We analyzed procedural data of 18 patients who underwent PVE from 2015 to 2018. A total of 29 portal branches were embolized (12 anterior branch, 11 posterior branch, 4 left branch, 2 right branch) with absolute ethanol and coils. Portal vein recanalization was evaluated three weeks after PVE by contrast-enhanced CT. We classified the treated portal branches as non-recanalized and recanalized. VER was compared between the groups. In addition, for each patient, we calculated and evaluated the ratio of FLR volume to total liver volume (volumetric %FLR), FLR count to total liver count on 99mTc-GSA SPECT/CT fusion imaging (functional %FLR), and functional-volumetric ratio (functional %FLR/ volumetric %FLR). RESULTS: Twenty-six portal branches showed no recanalization (non-recanalized group, n=26, 89.7%), while three portal branches showed recanalization (recanalized group, n=3, 10.3%). The median VER was 4.94% (3.12%-11.1%) in the non-recanalized group and 3.49% (2.76%-4.32%) in the recanalized group, which was significantly different between the groups (p = 0.045, Mann-Whitney U test). The median functional-volumetric ratio was 1.16 (1.03-1.50) in non-recanalized patients (n=15, 83.3%) and 1.01 (0.96-1.13) in recanalized patients (n=3, 16.7%), and it was significantly higher in the non-recanalized patients (p = 0.021, Mann-Whitney U test). CONCLUSION: The VER for preventing recanalization after PVE was approximately 5% (> 4.94%). 99mTc-GSA SPECT/CT fusion imaging revealed a decrease in FLR function due to recanalization after PVE.

Response to Immune Checkpoint Inhibitor Therapy in Patients with Unresectable Recurrent Malignant Pleural Mesothelioma Shown by FDG-PET and CT.

BACKGROUND: To compare three FDG-PET criteria (EORTC, PERCIST, imPERCIST) with CT criteria (combined modified RECIST and RECIST 1.1) for response evaluation and prognosis prediction in patients with recurrent MPM treated with ICI monotherapy. METHODS: Thirty MPM patients underwent FDG-PET/CT and contrast-enhanced CT at the baseline and during nivolumab therapy (median 10 cycles). Therapeutic response was evaluated according to EORTC, PERCIST, imPERCIST, and CT criteria. PFS and OS were examined using log-rank and Cox methods. RESULTS: CMR/PMR/SMD/PMD numbered 5/3/4/18 for EORTC, 5/1/7/17 for PERCIST, and 5/3/9/13 for imPERCIST. With CT, CR/PR/SD/PD numbered 0/6/10/14. There was high concordance between EORTC and PERCIST (κ = 0.911), and PERCIST and imPERCIST (κ = 0.826), while that between EORTC and imPERCIST (κ = 0.746) was substantial, and between CT and the three PET criteria moderate (κ = 0.516-0.544). After median 14.9 months, 26 patients showed progression and nine died. According to both PET and CT findings, patients with no progression (CMR/PMR/SMD or CR/PR/SD) showed significantly longer PFS and somewhat longer OS than PMD and PD patients (EORTC p = 0.0004 and p = 0.055, respectively; PERCIST p = 0.0003 and p = 0.052; imPERCIST p < 0.0001 and p = 0.089; CT criteria p = 0.0015 and p = 0.056). CONCLUSIONS: Both FDG-PET and CT criteria are accurate for response evaluation of ICI therapy and prediction of MPM prognosis. In comparison with CT, all three FDG-PET/CT criteria judged a greater percentage of patients (16.7%) as CMR, while two (EORTC, PERCIST) judged a greater percentage (10-13.3%) as PMD. For predicting PFS, the three FDG-PET criteria were superior to the CT criteria, and imPERCIST demonstrated the highest rate of accurate prediction.

Pelvic MRI, FDG-PET/CT, and Somatostatin Receptor Scintigraphy Findings of Treatment-Related Neuroendocrine-Differentiated Prostate Cancer.

Treatment-related neuroendocrine-differentiated prostate cancer (NEPC) is a rare tumor entity that transdifferentiates from adenocarcinoma as an adaptive response to androgen receptor pathway inhibition. We report a 79-year-old male with treatment-related NEPC, presenting as rectal bleeding after hormonal therapy. MRI showed a 51 × 52 × 65 mm tumor occupying almost the whole prostate gland and invading the seminal vesicle and rectum as moderately heterogeneous hypointensity on T2-weighted image, restricted diffusion on apparent diffusion coefficient map and diffusion-weighted imaging, and heterogeneous enhancement on Gd-enhanced T1-weighted image. FDG-PET/CT showed strong FDG uptake of the prostate tumor, and somatostatin receptor scintigraphy (SRS) showed mild uptake of the prostate tumor. The surgically resected specimen revealed NEPC. If prostate cancer worsens despite conventional therapy, treatment-related NEPC should be considered, and the benefit of imaging examinations including prostate MRI, FDG-PET/CT, and SRS is in localizing lesions with neuroendocrine differentiation.

Successful Embolization of Collaterals from the Round Ligament Artery during Uterine Artery Embolization for Traumatic Uterine Leiomyoma Rupture: A Case Report.

We describe the case of a 48-year-old woman who presented with traumatic rupture of a giant leiomyoma and massive hemoperitoneum caused by slipping and falling in the bathroom. She was in shock on arrival, and resuscitation was performed. Contrast-enhanced computed tomography showed massive intra-abdominal hematoma and extravasation from the subserous leiomyoma. Uterine artery embolization was performed, but she went into shock again after 6 h. The second contrast-enhanced computed tomography revealed persistence of extravasation. During 2nd UAE, an angiogram revealed extravasation originating from left round ligament artery. After the embolization of the left round ligament and bilateral uterine arteries, the patient recovered from shock. Total abdominal hysterectomy was performed on day 2 of admission to prevent re-bleeding and infection, then she discharged on day 19 of admission.

Comparison of modified Response Evaluation Criteria in Solid Tumors, European Organization for Research and Treatment of Cancer criteria, and PET Response Criteria in Solid Tumors for evaluation of tumor response to chemotherapy and prognosis prediction in patients with unresectable malignant pleural mesothelioma.

OBJECTIVE: To compare modified RECIST (mRECIST), EORTC criteria, and PERCIST for response evaluation and prognosis prediction in advanced malignant pleural mesothelioma (MPM) patients treated with chemotherapy. METHODS: Patients with MPM and not curative surgery candidates (n = 75) underwent standard chemotherapy with cisplatin and pemetrexed. CT and [F]fluorodeoxyglucose PET/CT scans were performed at baseline and after three chemotherapy cycles. Chemotherapeutic response was evaluated according to mRECIST, EORTC, and PERCIST, then concordance among those was assessed using Cohen's κ coefficient. PFS and OS were examined using log-rank and Cox methods. RESULTS: With EORTC, 27 patients had PMD, 23 SMD, 17 PMR, and eight CMR, while with PERCIST those were 28, 22, 11, and 14, respectively. Using mRECIST, 28 had PD, 29 SD, 18 PR, and 0 CR. Although there was high concordance between EORTC and PERCIST (82.7% of patients; κ = 0.83), that between mRECIST and EORTC (38.7%; κ = 0.27) and mRECIST and PERCIST (36.0%; κ = 0.26) was low. According to both EORTC and PERCIST, patients with no progression (CMR/PMR/SMD) showed significantly longer PFS and OS than PMD patients (EORTC: P = 0.0024 and P = 0.039, respectively, PERCIST: P = 0.0012 and P = 0.024, respectively), while according to mRECIST, those who achieved no progression (PR/SD) showed significantly longer PFS than PD patients (P = 0.011), but not significantly longer OS (P = 0.11). CONCLUSION: EORTC and PERCIST are more accurate than mRECIST for evaluation of tumor response to chemotherapy and predicting prognosis in unresectable MPM patients.

Future Liver Remnant Indocyanine Green Plasma Clearance Rate as a Predictor of Post-hepatectomy Liver Failure After Portal Vein Embolization.

PURPOSE: To evaluate the utility of future liver remnant plasma clearance rate of indocyanine green (ICGK-F) for predicting post-hepatectomy liver failure (PHLF) compared with percentage future liver remnant volume-to-total liver volume ratio (%FLR) after portal vein embolization (PVE). MATERIALS AND METHODS: PVE procedures in 20 patients (15 patients underwent PVE with absolute ethanol; 5 patients with gelatin particles) from 2010 to 2017 were analyzed. %FLR = future liver remnant volume (ml)/[total liver volume (ml) - tumor volume (ml)] × 100; ICGK-F = plasma clearance rate of indocyanine green (ICGK) × %FLR/100 were calculated before and after PVE. PHLF was categorized according to the criteria of the International Study Group of Liver Surgery. For predicting PHLF, we compared the ICGK-F and %FLR after PVE between the grade A PHLF group and the non-grade A PHLF (grades B and C) group. RESULTS: All PVE procedures were successful. While the ICGK-F of the grade A PHLF group (median 0.073, n = 16) was about twice that of the non-grade A PHLF group (median 0.043, n = 4), showing a significant difference (Mann-Whitney U test: P = 0.002), there was no significant difference in %FLR between the grade A PHLF group and the non-grade A PHLF group (Mann-Whitney U test: P = 0.335). CONCLUSION: ICGK-F was significantly higher in the grade A PHLF group than in the non-grade A PHLF group (grades B and C), and ICGK-F was more useful for predicting PHLF than %FLR.

Nonfatal air embolism complicating percutaneous CT-guided lung biopsy and VATS marking: Four cases from a single institution.

Systemic air emboli occur as a rare complication of percutaneous needle biopsy of the lung and video-assisted thoracoscopic surgery (VATS) marking. Here we present four cases of systemic air emboli from single institution and the imaging findings and embolism' kinetics using contrast-enhanced media during VATS color marking with indocyanine green. We suggest that early detection using routine whole-lung CT is required for asymptomatic patients with abnormal air. If abnormal air is found, we should keep the patient to the appropriate posture in order to prevent moving the air until it dissipates. Early detection of abnormal air can prevent severe complications.

Effect of the forward-projected model-based iterative reconstruction solution algorithm on image quality and radiation dose in pediatric cardiac computed tomography.

BACKGROUND: Some iterative reconstruction algorithms are useful for reducing the radiation dose in pediatric cardiac CT. A new iterative reconstruction algorithm (forward-projected model-based iterative reconstruction solution) has been developed, but its usefulness for radiation dose reduction in pediatric cardiac CT is unknown. OBJECTIVE: To investigate the effect of the new algorithm on CT image quality and on radiation dose in pediatric cardiac CT. MATERIALS AND METHODS: We obtained phantom data at six dose levels, as well as pediatric cardiac CT data, and reconstructed CT images using filtered back projection, adaptive iterative dose reduction 3-D (AIDR 3-D) and the new algorithm. We evaluated phantom image quality using physical assessment. Four radiologists performed visual evaluation of cardiac CT image quality. RESULTS: In the phantom study, the new algorithm effectively suppressed noise in the low-dose range and moderately generated modulation transfer function, yielding a higher signal-to-noise ratio compared with filtered back projection or AIDR 3-D. When clinical cardiac CT was performed, images obtained by the new method had less perceived image noise and better tissue contrast at similar resolution compared with AIDR 3-D images. CONCLUSION: The new algorithm reduced image noise at moderate resolution in low-dose CT scans and improved the perceived quality of cardiac CT images to some extent. This new algorithm might be superior to AIDR 3-D for radiation dose reduction in pediatric cardiac CT.

Initial Experience with Balloon-Occluded Trans-catheter Arterial Chemoembolization (B-TACE) for Hepatocellular Carcinoma.

PURPOSE: This study was performed to evaluate the accumulation of lipiodol emulsion (LE) and adverse events during our initial experience of balloon-occluded trans-catheter arterial chemoembolization (B-TACE) for hepatocellular carcinoma (HCC) compared with conventional TACE (C-TACE). METHODS: B-TACE group (50 cases) was compared with C-TACE group (50 cases). The ratio of the LE concentration in the tumor to that in the surrounding embolized liver parenchyma (LE ratio) was calculated after each treatment. Adverse events were evaluated according to the Common Terminology Criteria for Adverse Effects (CTCAE) version 4.0. RESULTS: The LE ratio at the level of subsegmental showed a statistically significant difference between the groups (t test: P < 0.05). Only elevation of alanine aminotransferase was more frequent in the B-TACE group, showing a statistically significant difference (Mann-Whitney test: P < 0.05). While B-TACE caused severe adverse events (liver abscess and infarction) in patients with bile duct dilatation, there was no statistically significant difference in incidence between the groups. Multivariate logistic regression analysis suggested that the significant risk factor for liver abscess/infarction was bile duct dilatation (P < 0.05). CONCLUSION: The LE ratio at the level of subsegmental showed a statistically significant difference between the groups (t test: P < 0.05). B-TACE caused severe adverse events (liver abscess and infarction) in patients with bile duct dilatation.

The relation between apparent diffusion coefficient and clinical stage of clear-cell renal cell carcinoma.

PURPOSE: The utility of the apparent diffusion coefficient (ADC) in patients with clear-cell renal cell carcinoma (RCC) for distinguishing between the four clinical stages was assessed. METHODS: Forty-nine patients with pathologically proven RCCs (I, II, III, IV; 27, 5, 10, 7) were included. The ADC was compared between each stage. RESULTS: The difference of ADC between stage I and the more advanced stages (III and IV) was statistically significant. CONCLUSIONS: When ADC in primary tumor site of clear-cell RCC would be higher than the cutoff level, the stage might not be an advanced stage (III or IV).

Comparison of utility of tumor size and apparent diffusion coefficient for differentiation of low- and high-grade clear-cell renal cell carcinoma.

BACKGROUND: There is a significant correlation between tumor size and tumor grade for clear-cell renal cell carcinoma (RCC) in pathology. Thus, apparent diffusion coefficient (ADC) of clear-cell RCC might be influenced by tumor size. PURPOSE: To compare the utility of tumor size and ADC for distinguishing low-grade from high-grade clear-cell RCC. MATERIAL AND METHODS: Forty-nine patients undergoing preoperative magnetic resonance imaging were retrospectively assessed. ADC values were calculated using b-value combinations of 0 and 800 s/mm(2) at 1.5 T. Two radiologists in consensus measured ADC values via small region of interest (ROI) (mean ROI area, 88.8 mm(2); range, 80-108 mm(2)) placement on an area of solid tumor on a single slice. Maximum tumor diameter was measured at the maximum tumor area. A single pathologist reviewed all pathological slides to determine the nuclear grade according to the Fuhrman classification. The utility of ADC, tumor size, and ADC/size ratio for distinguishing low-grade from high-grade tumors was assessed. Receiver-operating characteristic (ROC) analysis and regression analysis of the each index were performed. The correlation between ADC and tumor size was also investigated. RESULTS: The 49 clear-cell RCC included 34 low-grade and 15 high-grade tumors. The differences of ADC, tumor size, and ADC/size ratio between high-grade and low-grade tumors were statistically significant (P <0.05). The area under the ROC curve of ADC, tumor size, and ADC/size ratio were 0.802, 0.763, and 0.804 respectively. However, using regression analysis, only ADC (P <0.05) was statistically significant index as independent risk factors for high-grade clear-cell RCC. Moreover, weak significant correlation was observed between tumor size and ADC (R(2) = 0.3865, P <0.01). CONCLUSION: There was a weak significant correlation between tumor size and ADC value of clear-cell RCC. Using ROC and regression analysis, ADC was statistically significant index for distinguishing low-grade from high-grade clear-cell RCC more than tumor size and ADC/size ratio.

Magnetic resonance imaging features of angiomyofibroblastoma-like tumor of the scrotum with pathologic correlates.

Various tumors can occur in the scrotum. Among them, angiomyofibroblastoma-like tumors are very rare mesenchymal tumors. We report a case of an angiomyofibroblastoma-like tumor that arose in the right half of the scrotum in a 72-year-old man. It is difficult to separate angiomyofibroblastoma-like tumors from other malignant tumors invading the male genital tract on the basis of clinical characteristics and magnetic resonance imaging findings.