The impact of FDG-PET/CT in the management of patients with vulvar and vaginal cancer.

OBJECTIVES: To evaluate the changes in prognostic impression and patient management following PET/CT in patients with vulvar and vaginal carcinoma; and to compare PET/CT findings with those of conventional imaging modalities. METHODS: We summarized prospectively and retrospectively collected data for 50 consecutive patients from our institution that enrolled in the National Oncologic PET Registry and underwent FDG-PET/CT for a suspected or known primary or recurrent vulvar/vaginal cancer. RESULTS: 54/83 (65%) studies included had a diagnosis of vulvar cancer, and the remaining 29/83 (35%), a diagnosis of vaginal cancer. Following FDG-PET/CT, the physician's prognostic impression changed in 51% of cases. A change in patient management, defined as a change to/from a non-interventional strategy (observation or additional imaging), to/from an interventional strategy (biopsy or treatment), was documented in 36% of studies. The electronic records demonstrated that 95% of the management strategies recorded in the physician questionnaires were implemented as planned. MRI and/or CT were performed within one month of the FDG-PET/CT in 20/83 (24%) and 28/83 (34%) cases, respectively. FDG-PET/CT detected nodes suspicious for metastases on 29/83 (35%) studies performed. MRI and CT detected positive nodes on 6 and 11 studies respectively. Distant metastases were identified in 10 cases imaged with FDG-PET and 5 cases that had additional conventional CT imaging. All suspicious lesions seen on CT were positively identified on PET/CT. In 4 cases, an abnormality identified on PET/CT, was not seen on diagnostic CT. CONCLUSIONS: FDG-PET/CT may play an important role in the management of vulvar and vaginal carcinoma.

Updated prostate imaging reporting and data system (PIRADS v2) recommendations for the detection of clinically significant prostate cancer using multiparametric MRI: critical evaluation using whole-mount pathology as standard of reference.

OBJECTIVES: To evaluate the recommendations for multiparametric prostate MRI (mp-MRI) interpretation introduced in the recently updated Prostate Imaging Reporting and Data System version 2 (PI-RADSv2), and investigate the impact of pathologic tumour volume on prostate cancer (PCa) detectability on mpMRI. METHODS: This was an institutional review board (IRB)-approved, retrospective study of 150 PCa patients who underwent mp-MRI before prostatectomy; 169 tumours ≥0.5-mL (any Gleason Score [GS]) and 37 tumours <0.5-mL (GS ≥4+3) identified on whole-mount pathology maps were located on mp-MRI consisting of T2-weighted imaging (T2WI), diffusion-weighted (DW)-MRI, and dynamic contrast-enhanced (DCE)-MRI. Corresponding PI-RADSv2 scores were assigned on each sequence and combined as recommended by PI-RADSv2. We calculated the proportion of PCa foci on whole-mount pathology correctly identified with PI-RADSv2 (dichotomized scores 1-3 vs. 4-5), stratified by pathologic tumour volume. RESULTS: PI-RADSv2 allowed correct identification of 118/125 (94 %; 95 %CI: 90-99 %) peripheral zone (PZ) and 42/44 (95 %; 95 %CI: 89-100 %) transition zone (TZ) tumours ≥0.5 mL, but only 7/27 (26 %; 95 %CI: 10-42 %) PZ and 2/10 (20 %; 95 %CI: 0-52 %) TZ tumours with a GS ≥4+3, but <0.5 mL. DCE-MRI aided detection of 4/125 PZ tumours ≥0.5 mL and 0/27 PZ tumours <0.5 mL. CONCLUSIONS: PI-RADSv2 correctly identified 94-95 % of PCa foci ≥0.5 mL, but was limited for the assessment of GS ≥4+3 tumours ≤0.5 mL. DCE-MRI offered limited added value to T2WI+DW-MRI. KEY POINTS: • PI-RADSv2 correctly identified 95 % of PCa foci ≥0.5 mL • PI-RADSv2 was limited for the assessment of GS ≥4+3 tumours ≤0.5 mL • DCE-MRI offered limited added value to T2WI+DW-MRI.

Volume-based quantitative FDG PET/CT metrics and their association with optimal debulking and progression-free survival in patients with recurrent ovarian cancer undergoing secondary cytoreductive surgery.

OBJECTIVE: Our aim was to evaluate the associations between quantitative (18)F-fluorodeoxyglucose positron-emission tomography (FDG-PET) uptake metrics, optimal debulking (OD) and progression-free survival (PFS) in patients with recurrent ovarian cancer undergoing secondary cytoreductive surgery. METHODS: Fifty-five patients with recurrent ovarian cancer underwent FDG-PET/CT within 90 days prior to surgery. Standardized uptake values (SUVmax), metabolically active tumour volumes (MTV), and total lesion glycolysis (TLG) were measured on PET. Exact logistic regression, Kaplan-Meier curves and the log-rank test were used to assess associations between imaging metrics, OD and PFS. RESULTS: MTV (p = 0.0025) and TLG (p = 0.0043) were associated with OD; however, there was no significant association between SUVmax and debulking status (p = 0.83). Patients with an MTV above 7.52 mL and/or a TLG above 35.94 g had significantly shorter PFS (p = 0.0191 for MTV and p = 0.0069 for TLG). SUVmax was not significantly related to PFS (p = 0.10). PFS estimates at 3.5 years after surgery were 0.42 for patients with an MTV ≤ 7.52 mL and 0.19 for patients with an MTV > 7.52 mL; 0.46 for patients with a TLG ≤ 35.94 g and 0.15 for patients with a TLG > 35.94 g. CONCLUSION: FDG-PET metrics that reflect metabolic tumour burden are associated with optimal secondary cytoreductive surgery and progression-free survival in patients with recurrent ovarian cancer. KEY POINTS: • Both TLG and MTV were associated with optimal tumour debulking. • There was no significant association between SUVmax and tumour debulking status. • Patients with higher MTV and/or TLG had significantly shorter PFS. • SUVmax was not significantly related to PFS.

Volume and landmark analysis: comparison of MRI measurements obtained with an endorectal coil and with a phased-array coil.

AIM: To compare prostate volumes and distances between anatomical landmarks on MRI images obtained with a phased-array coil (PAC) only and with a PAC and an endorectal coil (ERC). MATERIALS AND METHODS: Informed consent was waived for this Health Insurance Portability and Accountability Act-compliant study. Fifty-nine men underwent PAC-MRI and ERC-MRI at 1.5 (n = 3) or 3 T (n = 56). On MRI images, two radiologists independently measured prostate volume and distances between the anterior rectal wall (ARW) and symphysis pubis at the level of the verumontanum; ARW and symphysis pubis at the level of the mid-symphysis pubis; and bladder neck and mid-symphysis pubis. Differences between measurements from PAC-MRI and ERC-MRI were assessed with the Wilcoxon RANK SUM test. Inter-reader agreement was assessed using the concordance correlation coefficient (CCC). RESULTS: Differences in prostate volume between PAC-MRI and ERC-MRI [median: -0.75 mm(3) (p = 0.10) and median: -0.84 mm(3) (p = 0.06) for readers 1 and 2, respectively] were not significant. For readers 1 and 2, median differences between distances were as follows: -10.20 and -12.75 mm, respectively, ARW to symphysis pubis at the level of the verumontanum; -6.60 and -6.08 mm, respectively, ARW to symphysis pubis at the level of the mid-symphysis pubis; -3 and -3 mm respectively, bladder neck to mid-symphysis pubis. All differences in distance were significant for both readers (p ≤ 0.0005). Distances were larger on PAC-MRI (p ≤ 0.0005). Inter-reader agreement regarding prostate volume was almost perfect on PAC-MRI (CCC: 0.99; 95% CI: 0.98-1.00) and ERC-MRI (CCC: 0.99; 95% CI: 0.99-1.00); inter-reader agreement for distance measurements varied (CCCs: 0.54-0.86). CONCLUSION: Measurements of distances between anatomical landmarks differed significantly between ERC-MRI and PAC-MRI, although prostate volume measurements did not.

Integrated diagnostics: proceedings from the 9th biennial symposium of the International Society for Strategic Studies in Radiology.

The International Society for Strategic Studies in Radiology held its 9th biennial meeting in August 2011. The focus of the programme was integrated diagnostics and massive computing. Participants discussed the opportunities, challenges, and consequences for the discipline of radiology that will likely arise from the integration of diagnostic technologies. Diagnostic technologies are increasing in scope, including advanced imaging techniques, new molecular imaging agents, and sophisticated point-of-use devices. Advanced information technology (IT), which is increasingly influencing the practice of medicine, will aid clinical communication and the development of "population images" that represent the phenotype of particular diseases, which will aid the development of diagnostic algorithms. Integrated diagnostics offer increased operational efficiency and benefits to patients through quicker and more accurate diagnoses. As physicians with the most expertise in IT, radiologists are well placed to take the lead in introducing IT solutions and cloud computing to promote integrated diagnostics. To achieve this, radiologists must adapt to include quantitative data on biomarkers in their reports. Radiologists must also increase their role as participating physicians, collaborating with other medical specialties, not only to avoid being sidelined by other specialties but also to better prepare as leaders in the selection and sequence of diagnostic procedures. Key Points • New diagnostic technologies are yielding unprecedented amounts of diagnostic information.• Advanced IT/cloud computing will aid integration and analysis of diagnostic data.• Better diagnostic algorithms will lead to faster diagnosis and more rapid treatment.

Prostate cancer imaging.

As prostate cancer is a biologically heterogeneous disease for which a variety of treatment options are available, the major objective of prostate cancer imaging is to achieve more precise disease characterization. Magnetic resonance imaging (MRI) may enhance the staging of prostate cancer compared with clinical evaluation, transrectal ultrasound, or computed tomography (CT), and allows concurrent evaluation of prostatic, periprostatic, and pelvic anatomy. In clinical practice, the fusion of MRI or dynamic contrast-enhanced MRI (DCE-MRI) with MR spectroscopic imaging (MRSI) is improving the evaluation of cancer location, size, and extent, while providing an indication of tumor aggressiveness. Pretreatment knowledge of these prognostic variables is essential for achieving minimally invasive, patient-specific therapy.

MR imaging and MR spectroscopic imaging in the pre-treatment evaluation of prostate cancer.

Magnetic resonance imaging (MRI) and proton magnetic resonance spectroscopy (1H MRSI) are emerging as the most sensitive tools for the non-invasive, anatomic and metabolic evaluation of prostate cancer. This article reviews the current applications of MRI and 1H MRSI in clinical practice and discusses the promise of these modalities for improving prostate cancer management. MRI demonstrates zonal anatomy with excellent contrast resolution and can reveal tumours in areas not routinely sampled on biopsy and not palpable on digital rectal examination. In addition, MR images allow assessment of local extent (including extracapsular extension and seminal vesicle invasion) and thus can assist in local staging while providing surgeons and radiation therapists with a visual road-map for treatment planning. The addition of 1H MRSI to MRI can improve prostate cancer detection and assessment of tumour volume; it also contributes indirectly to improved local staging. In addition, 1H MRSI metabolic and volumetric data correlate with pathological Gleason grade and thus may offer a non-invasive means to better predict prostate cancer aggressiveness. Combined MRI/1H MRSI is currently of greatest value for high-risk patients. With greater understanding of the relationship between spectroscopic data and tumour biology, it may become possible to use MRI/1H MRSI to achieve more precise stratification of patients in clinical trials, to monitor the progress of patients who select watchful waiting or minimally aggressive cancer therapies, and to guide and assess emerging local prostate cancer therapies.

Combined PET/MR: The Real Work Has Just Started. Summary Report of the Third International Workshop on PET/MR Imaging; February 17-21, 2014, Tübingen, Germany.

This paper summarises the proceedings and discussions at the third annual workshop held in Tübingen, Germany, dedicated to the advancement of the technical, scientific and clinical applications of combined PET/MRI systems in humans. Two days of basic scientific and technical instructions with "hands-on" tutorials were followed by 3 days of invited presentations from active researchers in this and associated fields augmented by round-table discussions and dialogue boards with specific themes. These included the use of PET/MRI in paediatric oncology and in adult neurology, oncology and cardiology, the development of multi-parametric analyses, and efforts to standardise PET/MRI examinations to allow pooling of data for evaluating the technology. A poll taken on the final day demonstrated that over 50 % of those present felt that while PET/MRI technology underwent an inevitable slump after its much-anticipated initial launch, it was now entering a period of slow, progressive development, with new key applications emerging. In particular, researchers are focusing on exploiting the complementary nature of the physiological (PET) and biochemical (MRI/MRS) data within the morphological framework (MRI) that these devices can provide. Much of the discussion was summed up on the final day when one speaker commented on the state of PET/MRI: "the real work has just started".

Developments in nuclear magnetic resonance imaging and spectroscopy: application to radiation oncology.

Nuclear magnetic resonance techniques have advanced to the point where functional, physiologic, and biochemical information may be obtained from patients. Magnetic resonance imaging of tissue water can be used to measure perfusion and diffusion with submillimeter resolution. Magnetic resonance spectroscopy may be applied to the assessment of tissue metabolites that contain protons, phosphorus, fluorine, or other nuclei. The combination of imaging and spectroscopy technologies has lead to spectroscopic imaging techniques that are capable of mapping proton metabolites at resolutions as small as 0.25 cm(3) within the time constraints of a clinical imaging study. This article provides a brief review of magnetic resonance techniques for imaging of tissue physiological function and addresses possible applications in the realm of radiation oncology.

Cancer of the uterus: the value of MRI pre- and post-irradiation.

In cancer of the uterus, the morphologic factors influencing the choice of therapy and patient prognosis are tumor size, depth of invasion, presence of lymph node metastasis, and stage. Clinical staging is often inaccurate with resultant suboptimal therapy, thereby invalidating comparison between treatment options. The available cross-sectional imaging modalities of ultrasound (US), computed tomography (CT) and magnetic resonance imaging (MRI), have significantly improved the staging of malignant disease. In the pelvis, MRI offers several advantages over the other imaging modalities. In particular, MRI has excellent soft tissue contrast resolution, allowing direct multiplanar imaging with evaluation of tumor extension in all three directions, and has variable imaging parameters (TR/TE)--characteristics of the echo patterns--to facilitate optimal tumor detection. It is a non-invasive technique with an ability to visualize blood vessels without the need for contrast injection and is independent of body habitus. However, MRI is not tissue-specific and a histological diagnosis is required in all cases. In the post-radiotherapy patient, MRI has the ability to demonstrate radiation tissue change and the potential to differentiate radiation fibrosis from recurrent/residual tumor. Its non-invasive nature and lack of ionizing radiation make it suitable for assessing treatment response and as an adjunct for patient monitoring.

Prostate volumes defined by magnetic resonance imaging and computerized tomographic scans for three-dimensional conformal radiotherapy.

PURPOSE: To compare the prostate volumes defined on magnetic resonance imaging (MRI), and noncontrast computerized tomographic (CT) scans used for three-dimensional (3D) treatment planning. METHODS AND MATERIALS: Ten patients were simulated for treatment using immobilization and a retrograde urethrogram. 3D images were used to compare prostate volumes defined by MRI (4-6 mm thick slices) and CT images (5 mm thick slices). Prostate volumes were calculated in cm(3) using the Scanditronix 3D planning system. MRI/CT images were merged using bony anatomy to define the regions of discrepancy in prostate volumes. RESULTS: The mean prostate volume was 32% larger (range-5-63%) when defined by noncontrast CT compared to MRI. The areas of nonagreement tended to occur in four distinct regions of discrepancy: (a) the posterior portion of the prostate, (b) the posterior-inferior-apical portion of the prostate, (c) the apex due to disagreement between a urethrogram based definition and the location defined by MRI, (d) regions corresponding to the neurovascular bundle. CONCLUSION: There is a tendency to overestimate the prostate volume by noncontrast CT compared to MRI. Awareness of this tendency should allow us to be to more accurately define the prostate during 3-D treatment planning.

Carcinoma of the cervix: predictive value of clinical and magnetic resonance (MR) imaging assessment of prognostic factors.

PURPOSE: This retrospective study assesses the predictive value of magnetic resonance imaging (MRI) to identify high risk cervical cancer patients. METHODS AND MATERIALS: The MRI evaluation of morphologic risk factors in patients with invasive cervical carcinoma treated with definitive radiation therapy were correlated with clinical factors and with complete tumor regression (CTR) at 6 months, tumor local control (TLC), and patient outcome at 12 months after irradiation. Sixty-six patients, median age 44.5 years, with bulky Stage I or greater disease were included in the study. RESULTS: In univariate analysis, clinical International Federation of Gynecology and Obstetrics (FIGO) stage had significant correlation with patient outcome, but it correlated poorly with complete tumor regression and tumor local control. In contrast, MRI stage showed significant correlation with complete tumor regression, tumor local control, and disease-free survival at 12 months. When each stage was analyzed separately, the greatest difference was demonstrated between clinical and MRI assignment of stage Ib disease. MRI Stage Ib disease significantly correlated with all three categories analyzed, while clinical Stage Ib did not. Superiority of MRI assessment of low stage disease was also evident in the detection of lymph node metastasis. Significant risk for nodal metastasis was related to tumor size greater than 4 cm, invasion of the parametria and urinary bladder, and stage of the disease. CONCLUSION: The multivariate analysis demonstrated that the most related variables in order of significance were the presence of juxta-regional and paraaortic lymph nodes, patient age, tumor size, and MRI tumor stage. This study demonstrates the value of MR imaging as an adjunct to clinical assessment of bulky invasive cervical cancer, rendering more complete assessment of morphologic risk factors important in patient prognosis.

Spermatic cord torsion: diagnostic limitations.

To distinguish spermatic cord torsion from other intrascrotal pathology, scrotal ultrasound and radionuclide scanning have been highly recommended on the basis of both clinical and experimental studies. We review the data from six patients in whom ultrasound or nuclear medicine examination was misleading. We emphasize that history, physical examination, and urinalysis remain the cornerstones of the diagnosis of spermatic cord torsion. Scrotal ultrasound and nuclear medicine scans are useful adjuncts and are reassuring when in agreement with the clinical picture. However, they are not 100% sensitive or specific, and a negative study should not prevent emergency operative exploration of a clinically suspicious lesion.

Clinical nuclear magnetic resonance imaging of the body.

NMR promises great advances in diagnosis and has delivered so much already that it is expected that in the future it will replace many applications of the currently used imaging modalities. Although x-ray computed tomography is continuing to advance in speed of scanning and resolving power, NMR will most likely soon eliminate its use in many studies of the central nervous system and also in many other areas of the body. The promise of combining topical spectroscopy with imaging is also exciting and should provide further information about metabolic processes of various organs. Progress in NMR is so rapid and the future is so bright that one of the great problems will be to develop a new breed of radiologists who are versatile in biochemistry, mathematics, and computers, as well as competent in morphologic anatomy and pathologic physiology. As time goes on, advances in NMR will be achieved only by teams of clinical and basic scientists encompassing multiple disciplines.

Phosphorus-31 MRS of the kidney.

Phosphorus-31 (31P) magnetic resonance spectroscopy of the kidneys promises to provide metabolic information leading to better assessment of renal physiology. However, the problems of studying the metabolism of the heterogeneous renal architecture by precisely localizing the origin of the signal obtained from small voxels and eliminating motion artifacts have not been solved as yet. The normal 31P MRS spectra show a characteristic fingerprint of six peaks including phosphomonoesters, phosphodiesters, inorganic phosphorus, and gamma, alpha, beta adenosine triphosphate (ATP). Renal failure, regardless of its etiology and mechanism of inducement (hypoxia, ischemia, acidosis, or obstruction) produces a loss of ATP with a progressive increase of inorganic phosphorus and a decline in intracellular pH. The severity of renal failure correlates with the severity of the metabolic disturbance. The potential use of 31P MRS in the assessment of renal viability has been applied to the study of renal preservation methods and prediction of renal function following transplantation.

Phosphorus-31 MRS of human testicular function and viability.

The current clinical use of magnetic resonance spectroscopy (MRS) is explored with attention to testicular function and pathology. Magnetic resonance spectroscopy provides insights into metabolic processes that are occurring in vivo. Information on these processes were, until now, only obtained through the use of invasive procedures such as biopsy, with the attendant undesired side effects. Phosphorus-31 (31P) MRS of the testes can provide unique metabolic information noninvasively and may provide clinicians with an alternative to the invasive procedures. The practical applicability of 31P MRS to the study of human infertility and testicular pathologies is described in some very preliminary studies.

Edema and the lack of blood perfusion produce opposite effects on the magnetic resonance characteristics of acutely ischemic rat kidneys.

Both kidneys of 28 rats were studied with magnetic resonance imaging (0.35 tesla, double spin-echo technique with echo-delay times [TEs] of 28 and 56 ms and repetition times [TRs] of 0.5 and 2.0 seconds). Kidneys were studied before and up to 4 hours after ligation of the abdominal aorta above the origin of the left renal artery (20 rats) or after ligation of the left renal artery (eight rats). Any changes in the relaxation times of cortex and medulla and in the cortex-to-medulla contrast (CMC) were correlated to histologic data and renal water content. After the first hour following ligation of either the abdominal aorta or the left renal artery, the cortex of the left kidneys showed a 20% shortening of the mean T2 relaxation time (P less than .001), a 16% shortening of the mean T1 relaxation time (P less than .001), a 73% increase in mean CMC on T2-weighted images (P less than .001) and a 42% decrease in mean CMC on T1-weighted images (P less than .001). There were no significant changes either in relaxation times of the medulla of the left kidneys or in relaxation times and CMC of the right kidneys. During the next three hours, relaxation times of cortex and CMC remained unchanged in the rats with ligated abdominal aorta. In the rats with ligated renal artery, relaxation times of cortex and CMC returned to normal values.(ABSTRACT TRUNCATED AT 250 WORDS)

Magnetic resonance imaging evaluation of radiation-induced changes in experimentally implanted renal cell carcinoma.

The effect of radiation on the magnetic resonance imaging appearance and relaxation parameters of human renal cell tumors implanted in male white-Swiss athymic nude mice was evaluated. Twenty-three mice were treated with external beam radiation, receiving a total dose of 2,500 rads administered in a single treatment limited to subcutaneous tumor. Twenty-two tumor-bearing mice served as control animals. Experimental and control mice were studied with MRI at four (n = 9), seven (n = 20), 14 (n = 8), and 28 (n = 8) days following experimental radiotherapy. A 0.35 tesla superconductive MRI system was employed. Images were generated using spin-echo technique with repetition times (TR) of 500 and 2,000 ms and echo-delay times (TE) of 28 to 30 and 56 to 60. Relaxation time calculations were made on the basis of tumor signal-intensity measurements in assigned regions of interest. The MRI appearances and relaxation times of irradiated tumors that decreased in size following treatment, irradiated tumors that grew, and control tumors were similar, as were their histologic features. No statistically significant differences could be detected in relaxation times of the four experimental and four control groups. Statistical evaluation was performed using analysis of variance. Further investigation of MRIs potential in tissue characterization following radiotherapy is warranted, but evaluation of change in tumor dimensions remains the most reliable indicator of therapeutic response.

Noncontrast and contrast enhanced MR imaging in the evaluation of partial ureteral obstruction: an experimental study in the micropig.

Twelve Yucatan micropigs (3 controls; 3 sham-operated; 6 with unilateral obstruction) were studied to assess the value of noncontrast and contrast-enhanced (Gadolinium-DTPA) magnetic resonance (MR) imaging in the evaluation of partial ureteral obstruction. MR findings were correlated with findings of quantitative (Tc-99m-DMSA) scintigraphy, and histology. On noncontrast T1-weighted images, the normal porcine kidney demonstrated good corticomedullary contrast (CMC = 16.8% +/- 5.0). Five minutes after administration of Gd-DTPA, there was enhancement of the renal cortex (+24.4% and medulla (+46.2%), and CMC was no longer discernible. Enhancement of the urine within the collecting system (+119.1%) was also observed. The obstructed kidneys demonstrated marked thinning of the renal parenchyma and decreased signal intensity on noncontrast T1- and T2-weighted images (P less than 0.01). Urine in the dilated collecting system did not differ significantly from urine in controls except in the three animals with urinary tract infection (P less than 0.05). Five minutes following injection of Gd-DTPA, there was enhancement of the renal parenchyma in all kidneys. Excretion was seen in three pigs and no excretion in two. Thus, useful information can be obtained in partial ureteral obstruction from both pre-contrast and Gd-DTPA-enhanced MR images of the kidney.