False-negative Imaging Research Articles

8737 Primary Hyperparathyroidism (PHPT) “Phenotypes” and the Results of Parathyroid [99mTc]Tc-Sestamibi SPECT/CT Scintigraphy: Minimizing the Risk of Negative Imaging Results

Abstract Disclosure: K. Kucharczyk: None. A. Drynda: None. J. Podlewski: None. M. Trofimiuk-Muldner: None. A. Hubalewska-Dydejczyk: None. Introduction. Primary hyperparathyroidism (PHPT) is a prevalent endocrinopathy typically identified through biochemical testing. PHPT is characterized by hypercalcemia accompanied by increased or inappropriately normal plasma parathyroid hormone (PTH) concentrations. Preoperative imaging is conducted when surgery is indicated to pinpoint parathyroid adenomas. [99mTc]Tc-Sestamibi scintigraphy is highly specific and sensitive in diagnosing PHPT, with a higher adenoma detection rate demonstrated for patients with larger lesions or higher blood calcium concentrations. The study aimed to investigate the relationship between the results of biochemical tests and clinical manifestations (PHPT “phenotype”) and the rate of positive results of parathyroid [99mTc]Tc-Sestamibi scintigraphy. Materials and methods. This was a retrospective study of patients suspected of PHPT who underwent parathyroid [99mTc]Tc-Sestamibi SPECT/CT scintigraphy between 2010 and 2022. Patients’ cluster analysis was conducted based on PTH, serum calcium (Ca), and phosphate (Pi) concentrations to find distinct patterns in these parameters. Furthermore, we compared the distributions of additional patients’ attributes, including gender, lesion size, serum vitamin D, ALP concentrations, urinary calcium, urolithiasis prevalence, as well as parathyroid scintigraphy results. Results. 513 patients were divided into 5 clusters using different algorithms. Finally, clusters from K-means methods were selected based on statistical metrics and expert interpretation. Those were organized in ascending order of positive scintigraphy results, with Cluster 5 reaching a 79.5% positivity rate and median values of PTH - 315.5 pmol/L, Ca - 2.96 mmol/L, and Pi - 0.7 mmol/L. As the proportion of positive imaging outcomes declined, median PTH and calcium concentrations decreased while phosphate concentrations increased. In Cluster 1, with 30% of positive imaging results, medians were as follows: PTH - 79.06 pmol/L, Ca - 2.55 mmol/L and Pi - 1.1 mmol/L. A comparative analysis of various clinical and biochemical parameters revealed statistically significant differences between clusters. Patients from Clusters with a higher frequency of positive scintigraphy were significantly more likely to be males, vitamin D deficient, with higher ALP concentrations, diagnosed with urolithiasis, and harbouring larger lesions. Conclusions. PHPT “phenotypes” correlated with disease severity are evidently linked to parathyroid scintigraphy detection rate. Therefore, it is crucial to know that false-negative imaging is more likely in PHPT patients with minor deviations in laboratory tests. Judicious assessment of biochemical and clinical features may limit the number of redundant parathyroid scintigraphies and, in consequence, reduce healthcare costs and unnecessary radiation exposure. Presentation: 6/2/2024

False negative breast cancers on imaging and associated risk factors: a single institution six-year analysis.

Mitigating false negative imaging studies remains an important issue given its association with worse morbidity and mortality in patients with breast cancer. We aimed to identify risk factors that predispose to false negative breast imaging exams. In an IRB-approved, HIPAA compliant retrospective study, we identified all patients who were diagnosed with breast cancer within 365days of a negative imaging study assessed as BI-RADS 1-3 between January 1, 2014 and January 31, 2020. A matched cohort based on mammographic breast density was created from randomly selected studies with BI-RADS 4-5 designation that yielded breast cancer at pathology within the same time frame. Patient and cancer characteristics, prior personal history of breast cancer and gene mutation status were collected from patient charts. Pearson chi-squared and Student's t-test on two independent groups with significance at < 0.05 was used for statistical analysis. We identified 155 false negative studies of 129 missed cancers and 128 breast density matched true positive cancers. False negative studies were screening mammograms in 57.42% (89/155), diagnostic mammograms in 29.68% (46/155), ultrasounds in 6.45% (10/155) and MRIs in 6.45% (10/155). Rates of personal (41.09% vs. 18.75%, p < 0.001) and family history of breast cancer (68.22% vs. 49.21%, p = 0.002) were higher in the false negative cohort and remained significant when asymptomatic MRI-detected cancers were removed. Our findings suggest that supplemental screening may be useful in breast cancer survivors.

Concordant GRADE-3 Truncal Ataxia and Ocular Laterodeviation in Acute Medullary Stroke.

Background: Severe truncal ataxia associated with an inability to sit up without assistance (STA grade 3) is frequent in patients with central acute vestibular syndrome (AVS) involving the brainstem or cerebellum. When these patients have nystagmus, central HINTS excludes peripheral lesions; however, additional localization and lateralization signs are helpful, not only to resolve the peripheral versus central vestibular lesion dilemma, but to zero in on a precise lesion localization/lateralization to the lateral medulla, the most common ischemic lesion localization associated with an initially false-negative stroke MRI. Methods: This is a study of AVS patients with additional inclusion criteria: grades 2 or 3 ataxia with an eventual diagnosis of medullary stroke (MS), either involving the lateral medulla (LMS) or the medial medulla (MMS), and horizontal (h) gaze paralysis was the main exclusion criteria. All patients sat on the side of the bed or stretcher, with assistance if needed. A general neurologic examination followed in the sitting position, the testing protocol included the head impulse, spontaneous nystagmus, and skew deviation (HINTS) tests, followed by observation of the effect of brief 3-5 sec eyelid closure on ocular position, and saccade and pursuit eye movement tests. If they could sit, the protocol included the ability to stand with a wide base, then a narrow base, the Romberg test, and tandem gait. Radiographic lesion localization and horizontal gaze deviation concluded the protocol. Results: A total of 34 patients met the entry criteria, 34 MS (13 in the lateral medulla, 12 previously described, and 1 new patient), and 1 new MMS. Among them, n = 10/12 had grade 3 ataxia, and 3 (1 new patient) had grade 2 ataxia. In addition, overt ocular laterodeviation (OLD) was present in thirteen of them (35.3%). All OLD patients had gaze deviation and ipsilateral saccade and truncal lateropulsion, 1 medial medulla stroke patient had grade 3 truncal contrapulsion and contralateral hemiparesis without OLD, n = 20/21 patients with LMS without OLD had grade 3 truncal ataxia, and 1 had grade 2 truncal ataxia. Discussion: AVS patients with severe truncal ataxia (inability to sit without assistance) potentially have brainstem, cerebellum, or subcortical lesions. All patients had central HINTS; however, simultaneous direction-concordant STA 3 and OLD provided greater lateral medulla localization specificity, affecting the ipsilateral medulla. Future work to explore a practical posterior circulation stroke scale that includes HINTS, STA, and OLD will potentially select cases for thrombolysis even in the event of initially false-negative imaging.

SAT193 Double Trouble: A Case of Ipsilateral Double Parathyroid Adenoma

Abstract Disclosure: J.P. Suelto: None. G.D. Wassmer: None. Background: Eighty percent of the cases of Primary Hyperparathyroidism is caused by a single adenoma and only about 15% are multiglandular adenoma. Parathyroid imaging like Sestamibi is less sensitive in detecting multiglandular disease. Clinical Case: A 63 year-old female presented with intermittent left lower back pain for 7 years. There was no joint pain, weakness, urinary symptoms, constipation and abdominal pain. In 2019, due to persistence of left back pain, abdominal ultrasound done showed a right non-obstructing nephrolithiasis. Ionized and total calcium were elevated at 1.53 meq/L (NV 1.12-1.32 meq/L) and 11.35 ng/dl (NV 8.42-10.23 ng/dl) respectively with normal creatinine, phosphorus and albumin. PTH was elevated at 116.6 pg/ml (NV 10-65 pg/ml). Primary Hyperparathyroidism probably secondary to parathyroid adenoma was considered. Thyroid ultrasound showed right thyroid cyst but no enlarged parathyroid gland. Parathyroid imaging using Dual Isotope Subtraction Method neither showed evidence of adenoma. Patient was advised parathyroidectomy but did not consent hence started on Cinacalcet. In 2021, ionized calcium was still elevated to 1.58 meq/L with elevated PTH 151 pg/ml and low Vitamin D level 22.76 ng/ml (&amp;gt;30 ng/mL). Patient was given Vitamin D3 2000 IU daily and Cinacalcet was up-titrated to 60mg daily. Sestamibi/SPECT CT showed faint focus of radioactivity in the right thyroidal bed area suspicious for parathyroid adenoma or hyperplasia. She then agreed to have parathyroidectomy. There was no decrease in PTH after removal of the right inferior parathyroid gland (measuring 1.8x0.6x0.6cm, weighs 500mg), hence re-exploration was done. It was only after the removal of the right superior parathyroid gland (measuring 2.8x0.9x0.7cm, weighs 1 gram) when the 5 and 10 minute post excision PTH decreased to 123.91 and 76.01 pg/ml respectively from preincision PTH of 407.19 pg/ml. Histopathology showed Parathyroid adenoma of right inferior and superior parathyroid glands. No further evidence of hypercalcemia was noted at 6-month follow-up. Conclusion: Double adenoma is reported in 2% to 12% of patients with primary hyperparathyroidism. This occurs predominantly as bilateral superior in 45% and on same side of the neck in 18%. Sestamibi scanning is poor in the presence of multiglandular disease. It was observed that the presence of oxyphil cells may cause longer sestamibi retention in parathyroid tissues. Given the same amount of oxyphil cells in ipsilateral adenomas, the tracer may be distributed hence faintly seen on imaging. Addition of SPECT/CT/4D CT may improve the anatomical localization. Another reason for false negative imaging in this patient can be due to use of Cinacalcet which may decrease scintigraphy uptake of parathyroid adenoma. The combination of preoperative imaging localization and intraoperative PTH monitoring permits successful surgical outcome. Presentation: Saturday, June 17, 2023

Adult patients with allied disorders of Hirschsprung's disease in emergency department: An 11-year retrospective study.

BACKGROUNDIn the past years, only a few studies with a limited number of adult patients analyzed clinical features of allied disorders of Hirschsprung’s disease (ADHD), most of which were individual case reports or lacked detailed clinical information. Although many studies have reported patients presenting to the emergency department (ED) with recurrent abdominal symptoms for a number of disorders, there are few data involving ADHD. However, owing to a lack of awareness of the disease, misdiagnoses and mistreatments are common. Severe complications such as perforation, bleeding, malabsorption, and even death in ADHD had been reported by many studies.AIMTo assist ED clinicians in having a more comprehensive understanding of this disease and making an early suspected diagnosis of ADHD more effectively.METHODSWe enrolled 53 patients who visited the ED and were eventually diagnosed with ADHD over the past 11 years in our hospital. Their basic information, clinical manifestations, and imaging findings were analyzed. Blood indices were compared between the ADHD and irritable bowel syndrome (IBS) groups.RESULTSAdult patients with ADHD had a mean age of 48.8 ± 14.3 years, and 77.4% had been treated before admission. The transverse colon was the most common dilated part (73.6%), and constipation (67.9%) was the most common symptom. ADHD patients can present with uncommon symptoms and false-negative imaging findings. Logistic regression analysis indicated that body mass index (BMI) [odds ratio (OR) = 0.786, P = 0.013], cholinesterase (per 1000 units; OR = 0.693, P = 0.008), and blood chlorine (OR = 0.816, P = 0.022) were determined to be independent related factors between the ADHD and IBS groups. The area under the receiver operating characteristics curve of these three indices combined was 0.812 (P < 0.001).CONCLUSIONEmergency physicians should be vigilant regarding patients with chronic constipation, abdominal pain, or abdominal distension, and consider the possibility of ADHD despite its rarity. Abdominal computed tomography examination is recommended as a useful tool in the suspected diagnosis of ADHD. BMI, cholinesterase, and blood chlorine have good discriminative abilities between ADHD and IBS. The nutritional status of adult patients with ADHD is worthy of further attention. Surgical treatment for adult patients with ADHD is important and inevitable.

Outcomes of pregnancies at high-risk for placenta accreta spectrum following negative diagnostic imaging.

To assess the pretest and negative post-test probability for placenta accreta spectrum (PAS) in a group of patients with high-risk clinical factors. We included patients with suspected and/or confirmed PAS at our institution over 8 years. Sonography performed by maternal-fetal medicine specialists, and selected patients underwent MRI. Imaging was considered positive if either sonography or MRI suggested PAS. Histopathology was the gold standard for diagnosis of PAS. We assessed the pretest and negative imaging-test probability, and resources required. We identified 82 high-risk patients with the following: (1) a history of≥1 cesarean section and/or intrauterine gynecologic procedure and placenta previa in the index pregnancy; (2) a history of >3 cesarean deliveries and/or gynecologic procedures regardless of placental location; (3) prior PAS disorder, or retained placenta requiring manual extraction and/or curettage, complicated by postpartum hemorrhage; and (4) suspected cesarean section scar pregnancy. Histopathology confirmed PAS in 52 patients, with pretest probability of 63%. Imaging correctly identified 44/50 cases with PAS, and excluded this condition in 24/30 cases. Thus, the positive and negative post-test probability for PAS following negative imaging was 88 and 20%, respectively. Of the six patients with false-negative imaging, all had either surgical complications or required care beyond that for routine cesarean section. Although diagnostic imaging is sensitive, the negative posttest probability remains high in women with high pretest probability for PAS. Therefore, women at high risk for PAS should be managed in experienced centers by a multidisciplinary team even if imaging is negative.

Frequency and Causes of False Negative Diffusion-Weighted Imaging in Acute Ischemic Stroke

Objective: The high sensitivity of diffusion-weighted magnetic resonance imaging (DWI MRI) has led to its frequent use in the diagnosis of acute ischemic stroke (AIS). However, false negative DWI MRI results have been obtained for some patients diagnosed with stroke, which led us to initiate this study. Our aim was to determine the prevalence of false negative DWI MRI scans and prevent the clinician from making a late diagnosis or misdiagnosis by relying on MRI results only.Methods: In a retrospective file screening conducted between February 2017- February 2019, after the patients hospitalized with a diagnosis of ischemic stroke who couldn't have an MRI or who were diagnosed with transient ischemic attack were excluded, the frequency of patients with a normal initial cranial DW MRI scan whose follow up scans revealed acute diffusion restriction was identified, and vascular anatomical localization of stroke was classified according to OCSP (Oxfordshire Community Stroke Project).Results: Of 235 patients admitted to our clinic with a diagnosis of ischemic stroke, 21 couldn't have a DWI MRI, and of 214 stroke patients who had a DWI MRI, 23 were admitted with a transient ischemic stroke attack. Of the remaining 191 patients, 14 had initially negative DWI MRI images but their clinical findings lasted longer than 24 hrs so they had a follow up MRI, which revealed an ischemic lesion in brain diffusion. In our clinic, the percentage of false negative diffusion MR images was 7.3% (14/191). The distribution of ischemia in the aforementioned 14 patients was as follows: 6 patients with posterior circulation ischemia (POCI), including 4 in brain stem and 2 in cerebellum, 2 patients with lacunar stroke (LACI), 5 patients with partial anterior circulation ischemia (PACI) and 1 patient with total anterior circulation ischemia (TACI).When the time of symptom onset was questioned, data could be derived from only 8 patients' files, and DWI MR images were obtained within the first 6 hours according to the onset of the symptoms.Conclusion: In acute stroke patients, if symptoms of the patient are consistent with stroke during physical examination, the diagnosis of stroke should not be automatically ruled out even if brain DWI MRI is negative. The decision of urgent thrombolytic or endovascular intervention that can be taken for eligible patients should not be overlooked based on false negative DWI MRI findings. With this study, we aim to help clinicians avoid misdiagnosis or delays in diagnosis.

Factors That Affect the Sensitivity of Imaging Modalities in Primary Hyperparathyroidism.

Background Cervical ultrasound, 99mTc-sestamibi single-photon emission computed tomography/computed tomography (99mTc-MIBI SPECT/CT), and cervical CT are routinely used in preoperative localization of primary hyperparathyroidism (PHPT). However, false-negative imaging results are also frequently encountered in clinical practice. Exploring the factors that affect the sensitivity of these imaging modalities is important for the surgical management of PHPT patients. Methods Clinical data of 352 PHPT patients hospitalized in our center from January 2011 to December 2015 were retrospectively collected to evaluate the sensitivity of 3 imaging modalities in the preoperative localization of parathyroid lesions. The ROC curve analysis was used to explore the clinical factors affecting the sensitivity of localization, and the cut-point(s) of related factors were determined. Results 99mTc-MIBI SPECT/CT has the highest sensitivity among the localization modalities commonly used, reaching 91.1% (86.0%–94.8%). When the lengths of parathyroid lesions were ≤1.3 cm, the sensitivity of neck ultrasonography significantly decreased, while the sensitivity of 99mTc-MIBI SPECT/CT decreased with parathyroid lesions ≤1.3 cm or serum PTH≤252 pg/ml. 99mTc-MIBI SPECT/CT was less effective in localizing the hyperplasia lesions. Neck ultrasonography combined with 99mTc-MIBI SPECT/CT can effectively improve the accuracy of preoperative localization of parathyroid lesions to 96.2% (92.7%–98.1%). Conclusions Small parathyroid lesion and mild elevation of serum PTH would reduce the accuracy of parathyroid localization in PHPT patients.

Tumor de células de Leydig puro de ovario en mujer premenopáusica

Los tumores de células de Leydig del ovario son un tipo raro de tumores del estroma del cordón sexual, con menos de 0,1% de todos los tumores de ovario. Representan un desafío diagnóstico, no solo por su incidencia esporádica sino también por presentar imágenes aparentemente normales. Aunque son más comunes en las mujeres menopaúsicas, también se ha descrito casos en mujeres premenopáusicas. La característica clínica más común es la aparición de virilización rápida y progresiva; más de 75% de las pacientes muestra signos de virilización debido a la sobreproducción de testosterona. La concentración sérica de testosterona representa el marcador más útil en el diagnóstico del tumor ovárico secretor de andrógenos. El tumor de células de Leydig ovárico siempre debe ser considerado en mujer en edad reproductiva con síntomas de virilización. Se presenta un caso de tumor de células de Leydig puro de ovario en mujer premenopáusica.

Accuracy of sentinel lymph node biopsy in invasive lobular carcinoma of the breast.

e12604 Background: The safety of the sentinel lymph node biopsy procedure (SLNB) in the surgical management of breast cancer relies upon a false negative rate (FNR) being less than 10%. The accuracy of SLNB in invasive lobular carcinoma (ILC), the second most common type of breast cancer, has not been evaluated. Because of high rates of false negative imaging and the diffuse growth pattern in ILC, less accurate pre-operative staging and a potentially unreliable lymphatic drainage pattern may impact the accuracy of SLNB in this tumor type. We therefore sought to characterize the accuracy of SLNB in a cohort of patients with ILC. Methods: We queried an institutional database of 707 patients with ILC and identified 196 patients who underwent SLN mapping with excision of both sentinel and non-sentinel nodes. A false negative was defined as having negative sentinel lymph nodes and a positive non-sentinel node. We calculated the FNR and sensitivity of SLNB and evaluated clinicopathologic variables. Results: Of 196 cases, 183 were clinically node-negative, 9 were clinically node-positive, and 4 had unknown clinical node status. Of the 183 clinically node-negative patients, 69 (37.7%) patients had node-positive disease at surgery. Overall, 7 of 196 cases had false negative SLNB, yielding an FNR of 8.97%. The sensitivity of SLNB was 91%. Patients with a false negative SLNB were significantly older than patients without (mean age 63 versus 54.7 years, p = 0.041). Significantly fewer sentinel and non-sentinel nodes were removed in women aged 50 years or older compared to those under 50 (1.9 vs. 2.5 sentinel nodes, p = 0.0158; 4.7 vs. 7.9 non-sentinel nodes, p = 0.0077). There were no differences in tumor receptor subtype, grade, stage, presence of lymphovascular invasion, or receipt of neoadjuvant therapy in those with a false negative SLNB compared to those without. Conclusions: The high rate of nodal positivity in clinically node negative patients highlights the challenges of clinical nodal assessment in ILC. Despite this, the SLNB procedure had a FNR that fell within the acceptable range, supporting its use in ILC. The relationship between number of sentinel nodes removed and FNR deserves further study, particularly in older women where extent of nodal surgery continues to decline.

MP79-02 PERFORMANCE CHARACTERISTICS OF PET/CT SCAN IN MEN TREATED WITH SALVAGE LYMPH NODE DISSECTION FOR RECURRENT PROSTATE CANCER: A PER PATIENT ANALYSIS WITH PATHOLOGICAL CONFIRMATION ACCORDING TO EACH AREA OF DISSECTION

MP79-02 PERFORMANCE CHARACTERISTICS OF PET/CT SCAN IN MEN TREATED WITH SALVAGE LYMPH NODE DISSECTION FOR RECURRENT PROSTATE CANCER: A PER PATIENT ANALYSIS WITH PATHOLOGICAL CONFIRMATION ACCORDING TO EACH AREA OF DISSECTION

Small bowel perforation following blunt abdominal trauma caused by an accidental hammer blow: A case report

Introduction. Trauma is among the leading causes of death. Undetected and untreated adequately and on time, traumatic small bowel injuries can be lethal. Case Report. We present a case of a small bowel perforation after a blunt abdominal injury, caused by an accidental self-inflicted hammer blow to the abdomen. The initial abdominal and chest x-rays and abdominal ultrasound did not indicate an injury to the abdominal organs. Due to the impaired clinical picture and the fact that the patient was hemodynamically stable, multi-detector computed tomography of the abdomen and small pelvis was performed, showing intraperitoneal free fluid and pneumoperitoneum, not seen by other imaging methods. A decision for surgical treatment was made. The intraoperative finding confirmed a small bowel perforation. Conclusion. Due to the possible false-negative imaging findings, clinical follow-up of patients with abdominal trauma is mandatory when making the decision for surgical treatment.

P5019Derivation and validation of a new probability score in pulmonary embolism suspicion allowing safely reduction of imaging testing: PEPS (Pulmonary Embolism Probability Score)

Abstract Background In pulmonary embolism (PE) suspicion, several strategies based on clinical criteria and D-dimer (Dd) measurement have been developed in order to reduce resource utilization. However, they used different clinical probability (CP) assessment methods limiting their combination. Purpose To develop and validate a unique probability score integrating most of previous proposals to allow safely reduction of imaging testing. Methods 4 CP levels were previously defined in order to obtain a false negative rate &lt;1.9%: 1) without Dd test: very low CP (PE prevalence &lt;1.9%), 2) with Dd &lt;1000 μg/L: low CP (&lt;15%), 3) with Dd &lt;500 or age x10μg/L: moderate CP (&lt;60%) and 4) precluding PE exclusion on Dd: high CP. We used individual data from 4 prospective cohorts of suspected PE patients in Europe and America (n=11 066) for derivation and internal validation. The variables significantly associated with PE in univariate analysis were included in a multivariate logistic regression model. Points were assigned according to the regression coefficients. The score was validated in two external independent cohorts (n=1554, n=1669). Results PEPS comprised 13 variables: age &lt;50 years (−2), age 50–64 years (−1), heart rate &lt;80 beats/min (−1), chronic lung disease (−1), chest pain and recent dyspnea (+1), syncope (+1), male sex (+1), previous venous thromboembolism (+2), medical or orthopaedic immobilization (+2), estrogenic treatment (+2), oxygen saturation &lt;95% (+3), unilateral lower limb pain (+3) and PE is the most likely diagnosis (+ 5). The rates of false negative and avoidable imaging tests if the PEPS strategy would have been applied were 0.6% [95% CI: 0.3–1.1] and 22.7% [20.2–25.3] in the first external validation cohort, and 0.85 [0.5–1.45] and 26.6% [23.5–29.9] in the second one. Applied retrospectively, PEPS strategy compared favourably with other strategies and combinations. Derivation Int. validation Ext. validation 1 Ext. validation 2 nPE/N % [95% CI] nPE/N % [95% CI] nPE/N % [95% CI] nPE/N % [95% CI] TOTAL 615/5588: 11.0% [10.2–11.9] 432/3726: 11.6% [10.6–12.7] 327/1546: 21.2% [19.2–23.2] 196/1669: 11.7% [10.3–13.4] Very low CP PEPS&lt;0 16/1445: 1.1% [0.7–1.8] 16/946: 1.7% [1.0–2.7] 3/118: 2.5% [0.7–6.8] 5/347: 1.4% [0.6–3.3] Low CP 0≤PEPS&lt;5 127/2620: 4.9% [4.1–5.7] 106/1805: 5.9% [4.9–7.1] 49/611: 8.0% [6.1–10.4] 61/647: 7.2% [5.7–9.1] Moderate CP 5≤PEPS&lt;12 347/1334: 26.0% [23.7–28.4] 243/867: 28.0% [25.1–31.1] 206/715: 28.8% [25.6–32.2] 107/430: 24.9% [21.0–29.2] High CP 12≤PEPS 125/179:69.8% [62.8–76.1] 67/108: 62.0% [52.6–70.6] 69/102: 67.7% [58.1–76.2] 23/45: 51.1% [37.0–65.0] AUC 0.84 [0.83–0.86] 0.82 [0.80–0.84] 0.79 [0.76–0.82] 0.77 [0.74–0.80] CP: Clinical probability; PEPS: Pulmonary Embolism Probability Score. Conclusions A strategy based on the proposed score may lead to a safely substantial reduction of imaging testing. It should now be tested in an outcome interventional study.

The impact of distinct triple-negative breast cancer subtypes on misdiagnosis and diagnostic delay.

Triple-negative breast cancer (TNBC) includes mostly aggressive types of breast cancer with poor prognosis. Due to its growth pattern, misinterpretation in clinical imaging is more frequent than in non-TNBC. As the group of TNBC contains heterogeneous types of tumors, marker expression-based subtypes have recently been established. We analyzed clinical features and false-negative imaging findings that could potentially lead to diagnostic delay within the subtypes. An exploratory analysis compared the imaging features across the a priori defined subtypes and related these findings to molecular subtype, disease stage, potential diagnostic delay, and patient outcome. TNBC cases were categorized into basal-like (BL; 38.6%), mesenchymal-like (ML; 19.9%), luminal androgen receptor (LAR; 28.3%), and immunomodulatory (IM; 13.3%) subtype. In almost every third patient, malignant classification was missed in at least one imaging method. Misclassification in mammogram was more frequent in ML, while benign ultrasound features were reported more often in the BL subtype. Diagnostic delay due to misclassification in imaging led to tumor growth and/or upgrading of the tumor stage in 8.9% of BL tumors, which had the lowest overall survivals. Despite misclassification rate was higher in the ML subtype it showed better outcomes. Misdiagnosis of axillary lymph node metastasis was higher in LAR; however, this subtype showed a higher percentage of affected axillary lymph nodes. TNBC subtypes have different clinical features, benign appearances, and diagnostic delay, which can lead to tumor stage upgrade. Future clinical studies on TNBC outcomes might consider the confounder of clinical delay in the subtypes.

Para-aortic plus pelvic lymphadenectomy in locally advanced cervical cancer: A single institutional experience

ObjectiveThe aim of the study is to assess the safety and efficacy of transperitoneal laparoscopic para-aortic and pelvic lymphadenectomy in the setting of surgical staging of patients with locally advanced cervical cancer (LACC), and to analyse the prognostic value and impact of this staging on the survival prognosis of this condition. Study DesignData from 67 patients with LACC who underwent transperitoneal laparoscopic para-aortic and pelvic lymphadenectomy and who received chemo-radiation therapy were retrospectively analysed. ResultsMetastatic lymph nodes (LN) were identified in 32 patients (47.7%), 20 (29.8%) had metastatic LN in the pelvic area and 12 (17.9%) had metastatic LN in the pelvic and para-aortic area. There were no skip metastases in the para-aortic area.After a median follow-up of 54.6 months (5–122.2 months), the 5-year local control and disease-free survival (DFS) rates for the whole group were 91.1% and 60.5% respectively. The five-year DFS for patients without LN metastasis was 86.4%, while for patients with pelvic LN metastases or pelvic and para-aortic metastases was 34.2% and 24.2% respectively (p < 0.001).The five-year overall survival (OS) for the whole group was 67.3%. The mortality rate in patients with para-aortic nodal metastases was increased compared to patients with negative nodes (5-year OS 21.3% vs 81.6% respectively, p = 0.005), but the OS rate was similar in patients with negative nodes and those with only pelvic nodes affected (5-year OS 81.6% vs 70.8% respectively, p = 0.380).This approach allowed the modification of the initial treatment plan in the para-aortic area in 13.4% of patients and in the pelvic area in 28.3%.The overall intraoperative morbidity rate was 5.9%, while the postoperative morbidity rate was 10.4%, with only 3 patients presenting grade 3 morbidity. ConclusionsTransperitoneal para-aortic and pelvic lymphadenectomy provides precise information about nodal state and allows personalized treatment planning in patients with LACC, avoiding false negative (FN) and false positive (FP) imaging results. In 17.9% of patients, the external beam radiotherapy (EBRT) field had to include the aortic area, whilst 47.7% received pelvic boost to the involved nodes.

Abstract P1-15-15: Accuracy of MRI after neoadjuvant therapy for invasive lobular carcinoma of the breast

Abstract Background: Invasive lobular carcinoma of the breast (ILC) has higher rates of false negative imaging than invasive ductal carcinoma, and lower rates of neoadjuvant therapy (NAT) use. We evaluated the accuracy of Breast Imaging Reporting And Data System (BIRADS) findings on magnetic resonance imaging (MRI) after either neoadjuvant chemotherapy or endocrine therapy, and determined whether imaging change correlates with disease free survival. Methods: We queried a database of 674 ILC cases treated at UCSF from 1981-2017 and identified all patients treated with NAT. We reviewed MRI reports and recorded BIRADS descriptors of findings, maximal tumor diameter for mass or non-mass enhancement (NME), and subjective radiologist comments on progression or improvement. We used the t-test, chi-squared test, Pearson's correlation, and Kaplan Meier survival estimates to evaluate the accuracy of MRI after NAT compared to true tumor size on pathology, and the relationship between imaging change and disease free interval in Stata 14.2. Results: Of 136 patients with ILC treated with NAT, we included 101 women who had a post-treatment breast MRI report available. Of these, 58.4% received neoadjuvant chemotherapy, and 41.6% neoadjuvant endocrine therapy. After NAT, MRI findings were mass only in 43%, both mass/NME in 33%, NME only in 18%, and neither in 5%. Maximal diameter of mass on post-treatment MRI underestimated true size by a mean of 3.3 cm (range -3.6 to 15.3 cm). NME size on post-treatment MRI underestimated true size by a mean of 1.87 cm (range -7.2 to 9.7 cm). Mass size on MRI underestimated true size by ≥1 cm in 61.5% of cases; this size discrepancy was associated with increased positive margins (46.4% versus 20%, p=0.011). NME size on MRI underestimated true size by at ≥1 cm in 65.6%. The correlation coefficient between mass size on MRI and true size was 0.34 (p=0.0041), which increased to 0.67 (p&amp;lt;0.0001) when excluding those with associated NME. The correlation coefficient between NME size on MRI and true size was 0.28 (p=0.1239). Subjective progression on post-treatment MRI was associated with increased recurrence rates (80% versus 18.3%, p=0.001). In those with subjective improvement on MRI, there was a trend towards longer disease free interval (89% versus 73% disease free at 4 years, p=0.13). Table 1.Patient and tumor characteristics. Neoadjuvant chemotherapy (n=59)Neoadjuvant endocrine therapy (n=42)P valueMean age (yrs, 95% CI)53.6 (50.9-56.3)61.3 (58.4-64.1)0.0002Subtype 0.105ER+ PR+ HER2-29 (53.7%)23 (62.16%) ER+ PR- HER2-14 (25.9%)13 (35.14%) ER- PR- HER2-1 (1.85%)0 HER2+10 (18.5%)1 (2.7%) Grade 0.076114 (25%)16 (38.1%) 237 (66.1%)26 (61.9%) 35 (8.93%)0 Surgical stage &amp;lt;0.001I17 (28.81%)28 (66.67%) II26 (44.07%)6 (14.29%) III16 (27.12%)8 (19.1%) Mean follow-up time (yrs, 95% CI)5.6 (4.53-6.75)5.1 (3.84-6.27)0.48 Conclusions: Maximal tumor diameter on MRI after NAT in ILC vastly underestimates true tumor size. While these findings suggest using caution when using an MRI for surgical planning in patients with ILC, particularly if there is associated NME, the trend towards improved disease free survival in those with a subjective improvement is intriguing and suggests that MRI changes could become an early predictor of outcomes. Citation Format: Fahrner-Scott KE, Wong JM, Piper M, Ewing C, Alvarado M, Esserman LJ, Hylton N, Mukhtar RA. Accuracy of MRI after neoadjuvant therapy for invasive lobular carcinoma of the breast [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P1-15-15.

Computed tomography in suspected anastomotic leakage after colorectal surgery: evaluating mortality rates after false-negative imaging.

We sought to investigate the accuracy of abdominal CT scanning for anastomotic leakage and the effect of false-negative scans on the delay in therapeutic intervention and clinical outcome. Data from a prospectively bi-institutionally maintained database of all patients who underwent elective colorectal surgery with primary anastomosis for malignant or benign disease between 2010 and 2017 were reviewed. Patients with confirmed anastomotic dehiscence at reintervention who underwent a postoperative CT scan for suspected leakage were identified and radiological reports were retrieved. Seventy-six patients with anastomotic dehiscence were included in the study. American Society of Anesthesiologists score, sex, type of surgical procedure, malignancy, and type of anastomosis do not correlate with postoperative false-negative CT imaging. Postoperative false-negative CT scan, however, led to delayed reintervention (3 vs. 6h, p = 0.023) and increased mortality (five deaths vs. no deaths, p = 0.043). Free abdominal air (p = 0.001) and extraluminal contrast extravasation (p = 0.001) were found to be predictive of accuracy in anastomotic leakage diagnosis. The suboptimal specificity of a postoperative CT scan in suspected anastomotic leakage after colorectal surgery can delay reintervention and increase mortality.

False-negative diffusion-weighted imaging in large vessel territory infarct

False-negative diffusion-weighted imaging in large vessel territory infarct

1828P - Role of SPECT-CT somatostatin-receptor scintigraphy in the management of medullary thyroid cancer (MTC)

Background: The MTC arises from the parafollicular, calcitonin-secreting malignant transformed thyroid C-cells who express on the surface somatostatin SSTR receptors. The most of aggressive locally advanced/metastatic MTC tumors, found to be positive for RET proto-oncogene mutation, are treated with Vandetanib. SPECT-CT somatostatin-receptor scintigraphy with 99mTc-Tektrotyd should be considered for MTC imaging before and after therapy for exact staging and follow-up of the disease due to its highly sensitivity and specificity for detection of neuroendocrine tumors, expressed SSTR. The aim of this study was to evaluate clinical role of SPECT-CT scintigraphy with 99mTc-Tektrotyd in the management of patients with MTC. Methods: 25pts (7M;18F) with MTC were studied; whole body somatostatin scintigraphy followed by target SPECT-CT studies were performed 2-4 hrs post i.v.inj. of 740 MBq 99mTc-Tektrotyd (Polatom). SPECT-CT camera Symbia T2, Siemens was used. Three of them were studied for initial pre-operative N/M-staging, 17 were follow-up after surgery. In 5 patients with metastatic disease SPECT-CT with 99mTc-Tektrotyd were performed before and after target therapy with Caprelsa (Vandetanib), 300mg/d orally. Results: Initial pre-operative staging showed 3 positive results for the primary tumor and metastatic lymph nodes and 2 false negative imaging of small 1-4 mm lung metastases. True negative results were obtained in 5 cases after thyroidectomy. True positive results were obtained in 17 cases with local recurrence in the thyroid bed, lymphadenopathy, osteolytic bone metastases, lung and subcutaneous lesions. False positive result was in 1 case with benign ovary cyst. Plasma levels of calcitonin vary from 94 to 5496 pg/ml in all 17 patients with local recurrence and/or metastatic lesions. In 5/17 cases SPECT-CT studies were used to evaluate effect of target therapy, respectively: partial response – in 2 cases, stable disease – in 2 cases and progressive disease – in 1 cases. Conclusions: SPECT-CT somatostatin-receptor scintigraphy with 99mTc-Tektrotyd is very useful functional imaging modality in patients with MTC in order to determinate personalized therapeutic disease approach. Legal entity responsible for the study: Sonya Sergieva. Funding: Has not received any funding. Disclosure: All authors have declared no conflicts of interest.

Laparoscopic paraaortic surgical staging in locally advanced cervical cancer: a single-center experience.

One aim of this study was to assess the efficacy and safety of laparoscopic paraaortic lymphadenectomy for paraaortic lymph node staging in locally advanced cervical carcinoma. The second aim was to identify prognostic factors in the evolution of this disease and to evaluate how the results of the surgery modify the oncological treatment of patients. We analyzed 59 patients diagnosed with locally advanced cervical cancer International Federation of Gynecology and Obstetrics stage IB2-IVA who underwent laparoscopic paraaortic lymphadenectomy at our hospital between 2009 and 2015. Depending on the results of the paraaortic lymphadenectomy, treatment consisted of pelvic- or extended-field chemoradiotherapy. The mean age at diagnosis was 52.3years. The median operative time was 180min. The mean hospital stay was 1.7days. The mean number of paraaortic lymph nodes excised was 16.4. Eight patients (13.5%) had positive paraaortic lymph nodes. Thirteen patients (22%) underwent surgery via the transperitoneal route, and 46 (78%) underwent surgery via the retroperitoneal route. The sensitivity and specificity of computerized axial tomography (CT) scanning for detecting paraaortic lymph node involvement was 75 and 86%, respectively. The statistically significant prognostic factors that affected survival were surgical paraaortic lymph node involvement, radiological pelvic lymph node involvement, and radiological tumor size as assessed with nuclear magnetic resonance. The rate of serious complications was 1.7%. Pretherapeutic laparoscopic paraaortic lymphadenectomy for locally advanced cervical carcinoma allows the adaption of radiotherapy fields to avoid false-positive and false-negative imaging results.