Oncologic PET/CT Imaging : Interpretation and Report Staff Lecture 전남대학교병원 핵의학과 권성영

Backgrounds  No standardization : reference lesion, structure (impression)  Not established terminology : shape, intensity, assessments of response, etc.  Variably from reader to reader 1)Communication gap with referring physician (critical to the continued success of PET/CT in the medical community) 2) Potential risk for legal problem

J Nucl Med 2010;51:158–163

J Nucl Med 2013;54:756–761  The written report - Communication between the physician interpreting an imaging study and the referring physician  patient management and clinical outcomes - legal documentation - justification of medical necessity, etc  PET/CT report - complexity of this hybrid imaging modality  more challenging than other imaging studies

J Nucl Med 2013;54:756–761

Outlines  Findings - Anatomic localization/extent and shape/intensity of FDG uptake - Interpretation of hybrid imaging (PET/CT)  Impression - Stratification of probability - Arrangement of imaging findings (e.g., redundancy, illogical conclusion, etc.)  Assessment of treatment response - Standardization of reporting

Findings

(F/49) For staging breast malignancy Small bowel?Sigmoid colon CT: negative Colonoscopy: not performed Anatomic localization

For restaging ovarian malignancy

Anatomic localization  Accurate localization : e.g., mesentery, mesocolon > RUQ abdomen 의 upper portion  Correct anatomy : e.g., hilar or interlobar area Lung lobe

Metabolic extent and shape Focal Diffuse Linear ??

Metabolic pattern: MIP !!!  mass like or focal: malignancy, recurred lesion, polyp, etc.  heterogeneous, irregular: 종양이나 염증 내부 morphology 기술  linear: esophagitis, colitis, SCM muscle  ill-defined: anastomotic site, benign lesion 의 경우처럼 주변과 경계 가 불분명한 경우  tubular (> segmental): colon cancer 에서 원통형으로 보일때 등

J Nucl Med 2013;54:756–761, modified Intensity  Qualitative terminology - mild, moderate, or intense - Variably from reader to reader  Semiquantitative terminology: SUV - Potential pitfall  Abnormal FDG uptake be compared with uptake in a normal reference region (e.g., normal liver) “mild” less intense than normal liver uptake “moderate” similar in intensity to normal liver uptake “intense” substantially higher than normal liver uptake  Lesion SUV can also be compared with SUV within a reference region of interest in the liver or mediastinal blood-pool activity.

CLINICAL IMPRESSION: For staging of PREVIOUS STUDY: none RADIOPHARMACEUTICAL: F-18 FDG SUVmean: liver (), mediastinum () FINDINGS: ( 괄호안은 maxSUV 값임 ) HEAD and NECK: no abnormal uptake CHEST, LUNG and MEDIASTINUM: no abnormal uptake ABDOMEN and PELVIS: no abnormal uptake MUSCULOSKELETON: no abnormal uptake CONCLUSION

Metabolic activity 기술시 유의사항  Partial volume effect 고려 - 평가를 할 수 있는 것과 평가 자체가 안 되는 경우 구분 - Lung nodule 에서 5-10 mm 이하의 경우 FDG 섭취 저명하지 않다고 benign lesion 으로 주면 안됨 (  uncharacterized nodule)  주변보다 높은 경우 metabolic activity 가 있다고 판단하되 그 정도는 앞의 기준에 맞춰서 적용

Interpretation of hybrid imaging (PET/CT)

PET (+)PET (-) CT (+) Main or significant lesions related with purpose of study Enlarged but non FDG-avid LN; pneumothorax, and nonavid lung nodules; vascular abnormalities such as aortic dilation or aneurysm; adrenal nodules; renal masses or stones; and gallstones CT (-) BAT, arthritis, pituitary adenoma, Warthin tumor, suspected colon polyp, or thyroiditis cyst, fibrosis J Nucl Med 2013;54:756–761, modified -*Consistency: independent of reader - Not diagnostic CT - Other imaging modalities (e.g., CT or MRI) performed concurrently - etc. (e.g., workload)

Impression

J Nucl Med 2013;54:756–761, modified Impression: requirement  Be a brief and concise interpretation of findings, not simply a restatement of findings !!  Be clear and unambiguous as possible  Be cautious to recommend additional imaging

Stratification of probability (draft)  R/O  desensitization in referring physician TerminologyStrength or impact High probability of ~ malignancy >95% ( 그 이외에 변수 없을 때 ) D/Dx 1 개 이상의 감별진단 필요시 most likely/least likely80-90:10-20 more likely/less likely60-70:30-40 no50:50 rather than Benign lesion 의 가능성이 높을 때 R/OUnexpected or undetermined lesion

Lung malignancy (SQC) with peritoneal metastasis maxSUV: 21.0maxSUV: Arrangement of imaging findings

Synchronous quadruple primary tumor

Distribution pattern

Difference of metabolic activity maxSUV: 12.3 maxSUV: 5.2 maxSUV: 3.7

Assessment of treatment response

Criteria of PERCIST 1.0  Complete metabolic response (complete resolution of FDG uptake) - less than mean liver activity - indistinguishable from surrounding background blood-pool  Partial metabolic response - more than a 30% decline (and drop of 0.8 unit) in SUL peak  Progressive metabolic disease - more than a 30% and 0.8 unit increase in SUL peak - new lesions  Stable metabolic disease - not meet other criteria

Assessment of tumor response (draft)  Complete metabolic response  Marked or significant improvement and no metabolic evidence of remained lesion  Partial metabolic response (30%)  Significant improvement but still remained state  Progressive metabolic disease  Significant aggravation of …  Stable metabolic disease  No significantly interval change

 PMR, SMD 사이 / SMD, PMD 사이  Somewhat (slightly) improving … / Somewhat aggravating  Mixed response (Wax and wane pattern) - newly developed lesion (  additional Tx) - aggravation (  additional Tx) - no change (  additional Tx or observation) - Improvement (  observation)

Further discussion  PET/CT as a follow-up study to anatomic imaging (e.g., CT alone) ?  Discordance of imaging findings between metabolic and anatomic imaging ?

Conclusion  Standardization of the structure and language of reports, taking into consideration the essential elements The accuracy of image interpretation and the quality of the diagnostic report are critical to the continued success of PET/CT in the medical community.

Take-home message  Understanding and recognition about reporting  F/U, F/U, F/U…  Active communication with referring physicians  Self-criticism (term, drawing a conclusion, etc)

Thank you for your attention !!

증례별 판독양식 붙임

PET/CT 판독 방향 (1)  검사 목적에 부합하는가 ? - Staging, restaging, MCUP 등의 목적에 맞게 결론이 합당하게 도 출되었는가  복수의 검사에서 진단성적 연속성을 유지할 수 있는가 ? - 모든 검사는 나름의 진단성적이 있음 (Abd. CT 에서 stomach, colon ca. 놓쳐도 소견상 말할 수 없으면 없는 것임 ) - anatomic location 의 일관성 - intra or interobserver variability (?? 검사가 많다고 안써주고 검사 가 없다고 더 써주는 것이 없어야 함 )

PET/CT 판독 방향 (2)  Nuclear Medicine 또는 functioning imaging 의 identity 를 반영하고 있는가 ? - 가능하면 metabolic status 로만 기술할 것 - Functionging imformation 을 제시하고 있는가 ? - PVE, image protocol 에 따른 제한점을 합리적으로 기술  Fusion imaging 의 판독방향을 제시하고 있는가 ? - PET 정보 CT 정보을 어떠한 방향으로 조합 ?  판독문 자체가 논리적인 방향으로 기술되어 있는가 ? - finding 에서 conclusion 이 합리적인 근거에 입각해서 제시되어 있는가 ?

PET/CT 영상 보는 순서  MIP 한번 돌려서 개략적인 위치 확인  Intensity 를 줄여서 brain parenchyme 판독 : cerebrovascular disease, hidden metastasis, low-FDG avid brain tumor, etc  Wholebody image 판독  CT 에서 liver, kidney contour 확인  Lung setting 에서 nodule 여부 확인  다시 MIP 한번 돌려서 병변 여부확인 ( 제일 중요 !!)

Staging

CLINICAL IMPRESSION: For staging of lung malignancy (lobe 위치, 조직형 ADC, SQC…) PREVIOUS STUDY: none RADIOPHARMACEUTICAL: F-18 FDG SUVmean: liver (), mediastinum () FINDINGS: ( 괄호안은 maxSUV 값임 ) HEAD and NECK: no abnormal uptake CHEST, LUNG and MEDIASTINUM: - ( ) lobe ( ) segment 에 약 cm sized hypermetabolic lesion 이 관찰됨 (). ( 필요시 주변 구조물 invasion 여부 기술 T staging) - Mediastinum and interlobar area 의 metastasis 여부 기술. - Both lung parenchyme 에 이상여부 기술 - pleura, effusion 여부 기술 ABDOMEN and PELVIS: no abnormal uptake MUSCULOSKELETON: no abnormal uptake CONCLUSION 1. Lung malignancy involving lobe (e.g., RUL, LUL) (T staging) : T staging 에 필요한 부가내용 기술 (satellite nodule, invasion 여부 ) 2. Multiple (or several) metastatic LAPs in … (N staging) 3. Metastatic lesions in … (M staging, 없으면 아예 쓰지 말것 )

CLINICAL IMPRESSION: For staging of lymphoma (biopsy site, 조직형 ) PREVIOUS STUDY: none RADIOPHARMACEUTICAL: F-18 FDG SUVmean: liver (), mediastinum () FINDINGS: ( 괄호안은 maxSUV 값임 ) HEAD and NECK: no abnormal uptake CHEST, LUNG and MEDIASTINUM: no abnormal uptake ABDOMEN and PELVIS: no abnormal uptake MUSCULOSKELETON: no abnormal uptake CONCLUSION 1. Lymphomatous involvements in …. 2. High probability of lymphomatous involvements 3. R/O Lymphomatous involvements 4. D/Dx 1) more likely 2) less likely 5. Benign …. rather than tumoral uptake in

CLINICAL IMPRESSION: For staging of breast malignancy, left/right PREVIOUS STUDY: none RADIOPHARMACEUTICAL: F-18 FDG SUVmean: liver (), mediastinum () FINDINGS: ( 괄호안은 maxSUV 값임 ) HEAD and NECK: no abnormal uptake CHEST, LUNG and MEDIASTINUM: - Left upper central breast 에 focal/ill-defined/mass like hypermetabolic lesion 이 관찰 됨 (). - Both axillary space 를 포함한 다른부위에 의의있는 FDG uptake 는 관찰되지 않음. ABDOMEN and PELVIS: no abnormal uptake MUSCULOSKELETON: no abnormal uptake CONCLUSION 1. Left breast malignancy 2. No metabolic evidence of metastasis

CLINICAL IMPRESSION: For staging of rectal/colonic malignancy PREVIOUS STUDY: none RADIOPHARMACEUTICAL: F-18 FDG SUVmean: liver (), mediastinum () FINDINGS: ( 괄호안은 maxSUV 값임 ) HEAD and NECK: no abnormal uptake CHEST, LUNG and MEDIASTINUM: no abnormal uptake ABDOMEN and PELVIS: - 에 약 cm length, hypermetabolic lesion () 이 관찰됨. - Ascending/Descending/Transeverse/Hepatic flexure/Splenic flexure colon 에 약 cm sized, focal/tubular/mass like/ill-defined hypermetabolic lesion 이 관찰됨. - 상기병변 주변으로 의의있는 FDG uptake 는 관찰되지 않음. - Pericolic space, 등 MUSCULOSKELETON: no abnormal uptake CONCLUSION 1. Colonic malignancy involving 2. No metabolic evidence of metastasis

Restaging

CLINICAL IMPRESSION: For restaging of malignancy PREVIOUS STUDY: RADIOPHARMACEUTICAL: F-18 FDG SUVmean: liver (), mediastinum () FINDINGS: ( 괄호안은 maxSUV 값임 ) HEAD and NECK: no abnormal uptake CHEST, LUNG and MEDIASTINUM: no abnormal uptake ABDOMEN and PELVIS: no abnormal uptake MUSCULOSKELETON: no abnormal uptake Compared with previous study(1 년 이내만 ), : No metabolic evidence of recurrence or metastasis