Intra and peritumoral PET radiomics analysis to predict the pathological response in breast cancer patients receiving neoadjuvant chemotherapy.

OBJECTIVE: The aim of our study was to evaluate the contribution of 18Fluorine-Fluorodeoxyglucose Positron Emission Tomography (18F-FDG PET) radiomic data obtained from both the tumoral and peritumoral area in predicting pathological complete response (pCR) in patients with locally advanced breast cancer receiving neoadjuvant chemotherapy (NAC). METHODS: Female patients with a diagnosis of invasive ductal carcinoma who received NAC were evaluated retrospectively. The volume of interest (VOI) of the primary tumor (VOI-T) was manually segmented, then a voxel-thick VOI was added around VOI-T to define the peritumoral area (VOI-PT). Morphological, intensity-based, histogram and texture parameters were obtained from VOIs. The patients were divided into two groups as pCR and non-complete pathological response (npCR). A "radiomic model" was created with only radiomic features, and a "patho-radiomic model" was created using radiomic features and immunohistochemical data. RESULTS: Of the 66 patients included in the study, 21 were in the pCR group. The only statistically significant feature from the primary tumor among patients with pCR and npCR was Morphological_Compacity-T (AUC: 0.666). Between response groups, a significant difference was detected in 2 morphological, 1 intensity, 4 texture features from VOI-PT; no correlation was found between Morphological_Compacity-PT and NGTDM_contrast-PT. The obtained radiomic model's sensitivity and accuracy values were calculated as 61.9% and 75.8%, respectively (AUC: 0.786). When HER2 status was added, sensitivity and accuracy values of the patho-radiomic model increased to 85.7% and 81.8%, respectively (AUC: 0.903). CONCLUSIONS: Evaluation of PET peritumoral radiomic features together with the primary tumor, rather than just the primary tumor, provides a better prediction of the pCR to NAC in patients with breast cancer.

A different perspective on PET/CT before treatment in patients with Hodgkin lymphoma: importance of volumetric and dissemination parameters.

The aim of this study is to investigate the role of the combination of volumetric and dissemination parameters obtained from pretreatment 18-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) in predicting the interim response and progression status in patients with Hodgkin lymphoma (HL). Pretreatment PET/CT images of HL patients were analyzed with LIFEx software, and volumes of interest (VOIs) were drawn with a fixed SUV 4.0 threshold. MTV, SUVmax, and TLG values were obtained from each VOI. Total MTV (tMTV) was calculated by summing the MTV values in all VOIs, and similarly, total TLG (tTLG) was obtained by summing the TLG values. The distance between the centers of the lesions was noted as Dmax, and the distance between the outermost voxels of the lesions as DmaxVox. tMTV/DmaxVox was calculated by dividing the tMTV value by the DmaxVox value, and tTLG/DmaxVox was calculated by dividing the tTLG value by the DmaxVox value. The correlation of pretreatment PET parameters with response groups (complete/poor) and relapse/progression status (stable/progressive) was statistically evaluated. A total of 52 patients were included in the study. Bulky disease, tMTV, tTLG, and tMTV/DmaxVox values were found to be significantly higher in the poor response group. tMTV > 190.60 ml was found to be the only prognostic factor predicting interim PET response. The tMTV/DmaxVox and tTLG/DmaxVox showed statistically significant differences between the groups with and without progression. tMTV/DmaxVox > 7.70 was found to be the only prognostic factor in predicting relapse/progression. The evaluation of tumor burden and dissemination together in 18F-FDG PET/CT before treatment in patients with HL can help us to predict the results of the patients.

Can pretreatment hepatic artery perfusion scintigraphy in patients with liver malignancies predict the treatment response of the selective internal radiation therapy with 90Y resin microspheres?

PURPOSE We aimed to evaluate whether the perfusion pattern from pretreatment hepatic artery perfusion scintigraphy (HAPS) in patients with liver malignancies can predict response to selective internal radiation therapy (SIRT). METHODS This retrospective study analyzed 152 consecutive patients treated with yttrium-90 (90Y) resin microspheres between April 2015 and July 2017. HAPS using single-photon emission computed tomography/computed tomography (SPECT/CT) with 99mtechnetium macroaggregated albumin (99mTc-MAA) was performed before SIRT. Investigators visually classified perfusion patterns of tumors as heterogeneous or diffuse in HAPS. Between diffuse and heterogeneous pattern group, positron emission tomography/computed tomography (PET/CT) and magnetic resonance imaging (MRI) were performed in third and sixth month after SIRT, and tumor response assessed and compared by using RECIST 1.1 or mRECIST. Overall survival (OS) and progression-free survival (PFS) were also compared with Kaplan-Meier/log-rank analyses. RESULTS Of 216 SIRT procedures, 172 were classified as heterogeneous and 44 as diffuse. Diffuse 99mTc- MAA uptake was associated with longer median OS than heterogeneous (22.2 vs. 14.4 months, respectively; P = .047). Subsegmental infusion was associated with longer OS than either lobar or segmental infusion (P = .090). Mean estimated OS was longer in patients with hepatocellular carcinoma (HCC) (34.2 months) than with colorectal carcinoma (CRC) (16.4 months) (P = .044). Patients with both diffuse and heterogeneous patterns were able to show complete response after SIRT. No statistically significant differences were observed between perfusion patterns and PFS or response rates to SIRT. CONCLUSION Although tumor perfusion patterns from preplanning HAPS analyses are useful for estimating tumor uptake of 90Y, they may not reliably predict hepatic treatment response, as patients with different perfusion patterns can show clinical response to SIRT.

The importance of anatomical localization of non-small cell lung carcinoma in predicting mediastinal lymph node metastasis.

Bronchopulmonary segmental location of non-small lung carcinomas is closely related to metastatic lymph node foci in the mediastinum. Our aim was to investigate the relationship between the anatomical locations of pulmonary masses on the bronchopulmonary segmental base and metastatic lymph node regions in non-small cell lung cancer using preoperative 18F-FDG PET/CT images. Ninety patients newly diagnosed with non-small cell lung carcinoma and referred to PET/CT imaging for staging were included in the study. Tumoral masses that could be evaluated visually and mediastinal node metastases were identified in 18F-FDG PET/CT images, then the relationship between them was investigated statistically. The diagnostic power of 18F-FDG PET/CT of mediastinal nodes was also revealed. Seventy-four males (82.2%) and sixteen females (17.8%) were enrolled in the study. Half of the patients were diagnosed as adenocarcinoma (50%). Investigation of the tumor location and mediastinal metastatic nodes revealed a statistically significant relationship between the apicoposterior segment of the left superior lobe and the left upper and lower paratracheal, subaortic, paraaortic, and left hilar regions according to the IASLC map. The sensitivity, specificity and accuracy of 18F-FDG PET/CT in the mediastinal nodes were 69.2%, 66.6%, and 68%, respectively. There was no statistically significant relationship between tumor location and 8th TNM Stage. Anatomical locations of non-small cell lung carcinomas can affect the disease stage and prognosis because of their tendency to metastasize to some mediastinal regions. However, this relationship needs to be investigated in larger study groups.

A prospective comparative study of ultrasonography, contrast-enhanced MRI and 18F-FDG PET/CT for preoperative detection of axillary lymph node metastasis in breast cancer patients.

AIM: We aimed to evaluate; (i) the accuracy of ultrasonography (US), contrast-enhanced magnetic resonance imaging (cMRI) and 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) for detection of axillary lymph node metastases (ALNMs), (ii) the role of late prone imaging, and (iii) the effect of PET/CT on preoperative staging of breast cancer. MATERIAL AND METHODS: From June 2015 to January 2019, 236 breast cancer patients were preoperatively exam ined using US, cMRI, and PET/CT and whom underwent pathological evaluations of axillary lymph nodes were analyzed. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy (ACC) of US, cMRI, and PET/CT for ALNMs were determined. RESULTS: There were 235 female and one male in our study. The mean age was 55,6±11,3 years. Of 158 patients who were histopathologically evaluated, 85 patients (36%) were negative and 73 patients (30.9%) were positive for ALNMs. The remaining 78 patients who were only radiologically evaluated with US and/or cMRI, 24 patients (10.2%) were negative and 54 patients (22.9%) were positive for ALNMs. The sensitivity, specificity, PPV, NPV, and ACC of PET/CT were 80.0%, 92.2%, 92.0%, 80.3%, and 85.7%, re spectively. The axillary lymph node, which was suspicious in supine imaging, remained in the suspicious group again in prone imaging in PET/CT. CONCLUSIONS: There is no single absolute modality for de tecting ALNMs in breast cancers to replace sentinel lymph node biopsy or axillary lymph node dissection. If ALNM is suspected based on PET/CT, axillary lymph node dissection without sentinel lymph node biopsy might be a better option because it is related to high possibilities of ALNM. KEY WORDS: Axillary lymph node metastasis, Magnetic resonance imaging, Ultrasonography, 18F-FDG PET/CT.

A prospective comparative study of contrast-enhanced CT, contrast-enhanced MRI and 18F-FDG PET/CT in the preoperative staging of colorectal cancer patients.

AIM: In patients with colorectal cancer an accurate diagnostic work-up is mandatory in order to perform the most specific treatment. In this study, we aimed to evaluate the accuracy of computed tomography (CT), magnetic resonance imaging (MRI) and 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) for detection of regional lymph node metastases (RLNMs) and the additional value of PET/CT in the preoperative staging of colorectal cancer. MATERIAL AND METHODS: From June 2015 to May 2018, 72 colorectal cancer patients were preoperatively examined using CT, MRI, and PET/CT. Histopathological examination of regional lymph nodes were performed in 53 patients who underwent colorectal surgery. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy (ACC) of CT, MRI, and PET/CT for RLNMs, and the additional value of PET/CT in distant metastases were determined. RESULTS: There were 44 male and 28 female in our study. The mean age was 61±11 years. Histopathologically, 27 patients (51%) were negative and 26 patients (49%) were positive for RLNMs. The sensitivity, specificity, PPV, NPV, and ACC of PET/CT were 88.5%, 59.3%, 67.6%, 84.2%, and 73.6%, respectively. PET/CT changed the patient management with diagnostic contribution to the suspicious lesions identified by radiological imaging modalities. CONCLUSION: PET/CT is a useful tool in the evaluation of colorectal cancer, and it allows to metabolically characterize undetermined lesions suspected for recurrence of disease, to perform a complete pre-surgical staging and to identify occult metastatic disease. PET/CT should be considered an essential diagnostic tool in the management of patients with colorectal cancer, especially in the preoperative staging. KEY WORDS: Colorectal Cancer, Computed tomography, Magnetic resonance imaging, Positron emission tomography.

The role and effect of FDG-PET/CT on patient management and restaging of bladder carcinoma.

OBJECTIVE: To compare the diagnostic role of Florine-18 2-fluoro-2-deoxy-D-glucose-Positron emission tomography/computed tomography (FDG-PET/CT) in the restaging of bladder cancer with other radiological methods and to determine its effect on the treatment management of patients with bladder cancer. MATERIAL AND METHODS: A total of 83 patients who showed suspicious lesions with radiologic methods and FDG-PET/CT images were enrolled in the study. Positive lesion sites were detected and compared in all imaging modalities. Positive lesions were confirmed by biopsy or serial radiological imaging. Furthermore, the rate of change of the management and treatment modalities of patients after FDG-PET/CT were noted. RESULTS: The most frequent metastasis was observed in lymphatic localizations in all imaging methods. Lymph node metastases was detected with FDG-PET/CT in 37/83 patients, with computed tomography in 28/80 patients, and with magnetic resonance imaging in 6/19 patients. Lymph node metastasis was detected most commonly in the pelvic region with all modalities. Following lymphatic localization in FDG-PET/CT and CT, metastases were found most frequently in the lung and bone regions. FDG-PET/CT also revealed 8 of the 12 local lesions that were detected by radiological methods and showed additional lesions in four patients that could not be demonstrated by radiological methods. FDG-PET/CT changed the treatment approaches in 34.9% (29/83) of patients. In 16 patients, it caused upstaging and commencement of advanced treatment methods. In 13 patients, malignancy was excluded in suspicious lesions and unnecessary advanced examination and treatment were avoided. FDG-PET/CT also caused three radical cystectomies, one partial cystectomy, and one urethrectomy in patients who had not undergone any operational procedure previously. CONCLUSION: Despite physiological urinary tract uptake, FDG-PET/CT is superior to other imaging modalities not only in distant localizations but also in evaluating pelvic lesions and lymph nodes. In addition, the use of FDG-PET/CT during the restaging process contributes to the management of maximum number of patients.

Unexpected Hepatic Uptake of Tc-99m-MAA in Lung Perfusion Scintigraphy in a Patient with End-stage Renal Disease

Extra-pulmonary accumulation of Tc-99m-macroaggregated albumin (MAA) is described as uptake areas out of the lung in perfusion scintigraphy. If the particles spread throughout the body before reaching the lung via venous collaterals or due to right-to-left shunt, or if the particles are too small to occlude the pulmonary capillaries, then the agent can be seen at different locations of the body. Extra-pulmonary accumulation of Tc-99m-MAA can be detected mostly in the liver as well as in the brain, kidney, thyroid, myocardium, spleen and vertebra. Herein, we present lung scanning images with unexpected hepatic accumulation of Tc-99m-MAA. This pulmonary perfusion scintigraphy was performed in a patient with end-stage renal disease due to dyspnea in the post-operative period of kidney transplantation